JP6009878B2 - Ink jet recording ink, ink cartridge, ink jet recording ink manufacturing method, ink cartridge manufacturing method, recording method - Google Patents

Description

  The present invention relates to an ink for ink jet recording, a method for manufacturing ink for ink jet recording, an ink cartridge, and a method for manufacturing an ink cartridge. In particular, the present invention relates to a fluorescent ink jet recording ink containing an organic fluorescent pigment using an organic solvent as a main solvent, a method for producing the same, and a recording method using the ink.

  Inkjet recording apparatuses are popular because they can be printed from a small number of copies, can be printed at low cost, and are easy to perform color printing. The ink used in the ink jet recording apparatus includes a water-based ink using water as a main solvent, an organic solvent-based ink using an organic solvent as a main solvent, a dye ink using a dye as a color material, and a pigment as a color material. Various things, such as the pigment ink used, are known. In addition to color inks such as black, cyan, magenta, and yellow, fluorescent color inks are also known.

  The fluorescent ink has higher visibility than the non-fluorescent ink. This is because the fluorescent dye radiates a part of the absorbed light energy together with the reflected light of the incident light source while changing the wavelength. High visibility makes it easy for humans to recognize and is widely used for advertising purposes and for warning signs.

  Further, from the viewpoint of cost, the inkjet recording apparatus is required to increase the printing speed and to quickly dry the printed matter. For that purpose, the ink for inkjet recording needs to be excellent in drying property. Furthermore, the safety of ink for inkjet recording, storage stability, stable ejection performance from the recording head, and the like are also required. In order to satisfy such performance, an organic solvent ink containing an inorganic pigment as a coloring material and an organic solvent as a main component as a solvent is used.

  Ink for ink jet recording using an organic solvent can be recorded on various recording media. For example, plain paper, synthetic paper, acrylic board, polyethylene terephthalate, polycarbonate, polyvinyl chloride base material (polyvinyl chloride base material is hereinafter referred to as a PVC base material), and the like. However, when used outdoors, a recording substrate having excellent water resistance is required. For example, synthetic paper, an acrylic board, a polyethylene terephthalate, a polycarbonate, a PVC base material is mentioned.

  As a fluorescent color ink, for example, an ink using an inorganic fluorescent pigment is disclosed in Patent Document 1. This technique discloses an ink-jet recording ink technique in which an inorganic fluorescent pigment is used as a fluorescent dye and an amine group-containing alcohol is added to prevent nozzle clogging of the recording head.

JP 2009-209316 A

  However, the ink for inkjet recording of Patent Document 1 uses an inorganic pigment that easily settles on a fluorescent pigment. Although it is described that the precipitation of the inorganic fluorescent pigment can be prevented by adding an amine group-containing alcohol, the storage stability at a low temperature at which the precipitation of the pigment is more remarkable has not been evaluated. Under low temperature, the Brownian motion of the inorganic fluorescent pigment is weakened, and it is considered that the particles tend to settle due to the bonding and aggregation of the particles. Therefore, there is a possibility that the inorganic fluorescent pigment in the ink settles at a low temperature. Therefore, it can be considered that the storage stability of the ink is poor at low temperatures. Therefore, there is a problem that stable ink ejection performance cannot be obtained.

  Therefore, an object of the present invention is to solve the above-described problems, and is excellent in drying property, safety, storage stability, water resistance, adhesion to a recording medium, and stable from a recording head. Provided are inks for fluorescent ink jet recording, ink cartridges, and methods for producing them.

  The ink for ink jet recording of the present invention is an ink for ink jet recording containing an organic fluorescent pigment, a pigment dispersant, an organic solvent, and a binder resin, and the organic fluorescent pigment is a synthetic resin dyed with a dye. The binder resin contains a vinyl chloride resin and an acrylic resin, and the ratio of the vinyl chloride resin and the acrylic resin in the ink for ink jet recording is 0.1 ≦ ((weight of the vinyl chloride resin) %) / (Weight% of the acrylic resin)) ≦ 3.0 and the content of the binder resin in the ink for ink jet recording is 1% by weight or more and 20% by weight or less. It is characterized by that.

  An ink cartridge according to the present invention includes the ink for ink jet recording described above, a pouch for storing the ink for ink jet recording, and a case for storing the pouch.

  An ink jet recording ink production method of the present invention is an ink jet recording ink production method comprising an organic fluorescent pigment, a pigment dispersant, an organic solvent, and a binder resin, wherein the organic fluorescent pigment is a dye. A dyed synthetic resin, wherein the binder resin includes a vinyl acetate resin and an acrylic resin, the organic fluorescent pigment and the pigment dispersant are dissolved in the organic solvent to obtain a pigment dispersion, and the salt The ratio of the vinyl acetate resin and the acrylic resin in the ink for inkjet recording is 0.1 ≦ ((wt% of the vinyl chloride resin) / (wt% of the acrylic resin)) ≦ 3.0 The pigment dispersion, the binder resin, and the organic solvent so that the content of the binder resin in the inkjet recording ink is 1 wt% or more and 20 wt% or less. A step of engagement, and having a.

  The ink cartridge manufacturing method of the present invention includes a step of storing the above-described ink for ink jet recording in a pouch and a step of storing the pouch in a case.

  The recording method of the present invention is a recording method of an ink jet recording apparatus that ejects ink for ink jet recording while a recording head having a plurality of nozzles is scanned in the main scanning direction of the recording substrate. The inkjet recording ink according to claim 7, wherein the inkjet recording ink is ejected onto a recording substrate by a first scan, and the recording substrate is transported in a sub-scanning direction. And the second scan after the first scan, the ink jet recording ink is ejected onto the recording substrate by the first scan by a nozzle other than the nozzle used in the first scan. And a step of discharging the ink for ink jet recording at a position.

  ADVANTAGE OF THE INVENTION According to this invention, the ink for fluorescent inkjet recording which is excellent in drying property, safety | security, storage stability, water resistance, and adhesiveness with a recording medium, and can discharge stably from a recording head can be provided.

FIG. 1 is an exploded perspective view of an ink cartridge according to a preferred embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described.
The ink for ink jet recording needs to contain an organic fluorescent pigment, a pigment dispersant, a binder resin, and an organic solvent.
Organic fluorescent pigments are manufactured by dyeing one or more synthetic resins of polyamide resin, formaldehyde polycondensate, ketone resin, and vinyl copolymer, and an oily dye or basic dye as a colorant. It has been done.

For example, organic fluorescent pigments include FM-11, 12, 13, 14, 15, 16, 17, 27, 34N, 35N, 47, 103, 105, 107, and 109 manufactured by Sinlohi.
There are organic solvents that can dissolve such organic fluorescent pigments. By dissolving the organic fluorescent pigment in the organic solvent, it is not necessary to control the pigment particle diameter, the adjustment can be easily performed, and the synthetic resin constituting the organic fluorescent pigment has a binder function. Becomes a small amount.
Furthermore, the organic fluorescent pigment dissolves in the ink for ink jet recording, so there is no risk of sedimentation due to aggregation of the pigment, so the storage stability of the ink for ink jet recording is improved and the stable ejection performance from the recording head is maintained. There is an advantage that it becomes possible to do.

  The content of the organic fluorescent pigment in the ink is 8% by weight or more and 30% by weight or less, and preferably 8% by weight or more and 20% by weight or less. In general, when a pigment is used, the content of the pigment in the ink is about 5% by weight to 10% by weight. When an organic fluorescent pigment is used, the amount is larger than that. For this reason, the fluorescence ink has a higher viscosity than the color ink due to the difference in pigment content, and the amount of binder resin added is limited, making it difficult to obtain sufficient adhesion to the recording substrate. There is a problem of becoming. However, such a problem can be solved by using a vinyl chloride resin and an acrylic resin as a binder resin. When the content of the organic fluorescent pigment in the ink for inkjet recording is less than 8% by weight, sufficient visibility cannot be obtained on the printed matter. On the other hand, if it exceeds 30% by weight, the viscosity of the ink for ink jet recording becomes high, and not only the stable ejection performance from the recording head cannot be maintained, but also a sufficient binder resin cannot be added to the recording medium. Ink adhesion is insufficient, which is not preferable.

As a pigment dispersing agent, a phthalocyanine ammonium salt-based, polyester-amines, fatty amines, polyalkylene down imine, and the like can be used polyester polyamide, basic dispersant.

In particular, the amine value of the pigment dispersing agent is polyalkylene down imine or basic dispersant for the range 10 mgKOH / g or higher 50 mg KOH / g are preferred. This is because the organic fluorescent pigment is suitably dissolved. The reason is not clear, but it is considered that the presence of the pigment dispersant in the ink causes the solubility of the pigment dispersant and the organic fluorescent pigment, which have high dispersion solubility in the organic solvent, to be increased.

The content of the pigment dispersant in the ink is preferably in the range of 1% by weight to 5% by weight. More preferably, it is 3% by weight or less. When the content of the pigment dispersant in the ink for ink jet recording is less than 1% by weight, the storage stability of the ink for ink jet recording cannot be maintained, which is not preferable. When it exceeds 5% by weight, the blocking property and chemical resistance of the printed matter are insufficient, which is not preferable.
As the binder resin, a vinyl acetate resin and an acrylic resin having methyl methacrylate and butyl methacrylate as constituent monomers are used in combination.

  The average molecular weight A of the vinyl chloride resin is preferably in the range of 20000 ≦ A ≦ 30000. When the average molecular weight A is less than 20000, the adhesion to the recording substrate and the stable ejection performance from the recording head are impaired, which is not preferable. When the average molecular weight A exceeds 30000, the adhesion to the recording substrate, the stable ejection performance from the recording head, and the drying property of the printed matter are impaired, which is not preferable.

  The average molecular weight B of the acrylic resin having methyl methacrylate and butyl methacrylate as constituent monomers is preferably in the range of 45000 ≦ B ≦ 75000. If the average molecular weight B is less than 45,000, not only the adhesion of the printed matter is impaired, but also the solid content concentration in the ink is increased, and the stable ejection performance from the recording head is impaired, which is not preferable. When the average molecular weight B exceeds 75,000, the viscosity of the ink becomes high even when added in a small amount, and it becomes difficult to obtain stable ejection performance from the recording head.

  Furthermore, the ratio of the resin weight% of the vinyl chloride resin of the binder resin and the acrylic resin having methyl methacrylate and butyl methacrylate as constituent monomers is 0.1 ≦ ((resin weight% of the vinyl chloride resin) / (Resin weight% of acrylic resin having methyl methacrylate and butyl methacrylate as constituent monomers)) ≦ 3.0, preferably within a range of 0.1 ≦ ((resin weight% of vinyl chloride resin) / ( A range of the ratio of the resin weight% of the acrylic resin having methyl methacrylate and butyl methacrylate as constituent monomers)) ≦ 2.0 is particularly preferred. When the ratio of the resin weight% of the vinyl chloride resin and the resin weight% of the acrylic resin containing methyl methacrylate and butyl methacrylate as the constituent monomer is less than 0.1, the adhesion to the recording substrate, from the recording head This is not preferable because the stable discharge performance is impaired. When the ratio of the resin weight% of the vinyl chloride resin and the resin weight% of the acrylic resin exceeds 3.0, the drying property of the printed matter and the stable ejection performance from the recording head are impaired, which is not preferable.

  The content of the binder resin in the ink is preferably in the range of 1% by weight to 20% by weight, and more preferably 2% by weight to 10% by weight. When the content of the binder resin in the ink for ink jet recording is less than 1% by weight, the adhesion with the recording substrate becomes insufficient. When it exceeds 20% by weight, the viscosity of the ink for ink jet recording becomes high, and it is not preferable because stable ejection performance from the recording head cannot be maintained. However, if more fluorescent ink can be fixed on the recording substrate, the visibility is better. When recording is performed by discharging fluorescent ink from a recording head, the more fluorescent fluorescent pigment on the recording substrate, the stronger the fluorescent color. For example, double the amount of ink is fixed by discharging the fluorescent ink in the same position on the recording substrate. By scanning the recording substrate at least twice and ejecting the fluorescent ink at the same position, twice the amount of the organic fluorescent color pigment can be fixed at the same position. Visibility can be further increased by using such a recording method.

  The organic solvent which is the solvent for the ink for ink jet recording is used as a main solvent having a ratio of 50% by weight or more in the solvent, at least one selected from glycol monoacetates and glycol ethers alone or in combination. When this organic solvent is used, it can be satisfactorily discharged from the recording head.

  For example, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate, Ethylene glycol monomethyl ether propionate, ethylene glycol monoethyl ether propionate, ethylene glycol monobutyl ether propionate, diethyl diglycol, diethylene glycol dialkyl ether, tetraethylene glycol dialkyl ether, Ethylene glycol monomethyl ether propionate, diethylene glycol monoethyl ether propionate, diethylene glycol monobutyl ether propionate, propylene glycol monomethyl ether propionate, dipropylene glycol monomethyl ether propionate, ethylene glycol monomethyl ether butyrate, ethylene glycol mono Ethyl ether butyrate, ethylene glycol monobutyl ether butyrate, diethylene glycol monomethyl ether butyrate, diethylene glycol monoethyl ether butyrate, diethylene glycol monobutyl ether butyrate, propylene glycol monomethyl ether butyrate, dipropylene glycol monomethyl ether butyrate Which glycol monoacetates, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol diethyl ether, ethylene glycol dimethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol ethyl methyl ether, diethylene glycol Dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene Glycol monoethyl ether, propylene glycol dimethyl ether, dipropylene glycol dimethyl ether, propylene glycol diethyl ether, dipropylene glycol diethyl ether, ethylene glycol monomethyl acetate, ethylene glycol monoethyl acetate, ethylene glycol monobutyl acetate, diethylene glycol monomethyl acetate, ethylene glycol monomethyl Ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, diethylene glycol monoethyl acetate, diethylene glycol monobutyl Seteto, triethylene glycol monobutyl ether, glycol ethers such as tetraethylene glycol dimethyl ether. Among these, ethylene glycol monobutyl ether acetate (ethylene glycol monobutyl ether acetate is hereinafter referred to as BGAc) is particularly preferable from the viewpoint of solubility of the binder resin and the organic fluorescent pigment.

  As co-solvents, aromatic compounds such as toluene and xylene, γ-butyrolactone (γ-butyrolactone is hereinafter referred to as GBL), lactone solvents such as γ-valerolactone, N-methyl-2-pyrrolidone, N-ethyl And nitrogen-containing compounds such as -2-pyrrolidone and acetonitrile. These can be used in combination with a plurality of solvents as required. These sub-solvents are preferably less in consideration of the influence on the base material of the recording medium, and the content in the ink is preferably 10% by weight or less.

As the additive, a plasticizer, a surface conditioner, an ultraviolet ray inhibitor, a light stabilizer, an antioxidant and the like can be used.
The ink for inkjet recording is manufactured by adding a binder resin and an organic solvent to a pigment dispersion obtained by dissolving an organic fluorescent pigment and a pigment dispersant in an organic solvent in advance, and stirring the mixture using a stirrer.
Ink jet recording ink is used in an ink jet recording apparatus while being stored in an ink cartridge. The ink cartridge will be described with reference to FIG.

FIG. 1 is an exploded perspective view of an ink cartridge according to a preferred embodiment of the present invention.
The ink cartridge 1 includes a flexible pouch (ink bag) 2 in which ink for ink jet recording is accommodated, and an upper case 3 and a lower case 4 in which the pouch 2 is accommodated. In the pouch 2, ink for ink jet recording is stored. The case 4 which is the upper case 3 is fitted, and the pouch 2 is stored inside. Pouch 2 has two layers of aluminum foil to improve gas barrier properties, for example, two aluminum laminate films sandwiched between nylon film on the outside and polyethylene film on the inside, and the periphery is joined by thermal welding or the like Is made up of. One end of the pouch 2 is provided with an ink outlet 5 for discharging the ink contained therein to the outside. In order to supply the ink in the pouch 2 to the outside, the lower case 4 is provided with a hole through which the ink outlet 5 is exposed. This ink cartridge is manufactured by a process including a step of filling and storing the ink for ink jet recording in the pouch 2 and a step of storing the pouch 2 in the case 4 having the upper case 3 as the pouch 2. Further, the ink filling preferably includes a step of putting ink in an opening of the pouch 2 in a vacuum chamber, degassing, and sealing the opening. The ink cartridge shown in FIG. 1 that accommodates ink for ink jet recording is a preferred embodiment of the ink cartridge of the present invention, but the ink cartridge of the present invention is not limited to this form of ink cartridge.

Hereinafter, an example is given and it demonstrates concretely. In the examples, “part” represents “part by weight”.
The composition of the ink for inkjet recording is summarized in Table 1. For the ink for inkjet recording, an organic fluorescent pigment, a pigment dispersant, an organic solvent, and a binder resin were prepared so that the total amount was 100 parts. A binder resin and an organic solvent are added to a pigment dispersion in which an organic fluorescent pigment and a pigment dispersant are dissolved in an organic solvent in advance, and the binder resin is stirred for 4 hours at a rotational speed of 1200 rpm while being heated to 60 ° C. Was dissolved to obtain an ink for inkjet recording.

Example 1
The organic solvent is 77.5 parts BGAc, 3.8 parts GBL, 12.0 parts organic fluorescent pigment, 2.4 parts pigment dispersant, and vinyl acetate resin (average molecular weight 25000) is 1. An ink using 7 parts and 2.6 parts of an acrylic resin (average molecular weight 50000) was prepared.
(Example 2)
The organic solvent is 78.2 parts of BGAc, 3.8 parts of GBL, 10.0 parts of the organic fluorescent pigment, 2.0 parts of the pigment dispersant, and the vinyl chloride resin (average molecular weight 25000) is 1. An ink was prepared using 0 part and 5.0 parts of an acrylic resin (average molecular weight 50000).
(Example 3)
The organic solvent is 79.2 parts of BGAc, 3.8 parts of GBL, 10.0 parts of the organic fluorescent pigment, 2.0 parts of the pigment dispersant, and the binder resin is a vinyl acetate resin (average molecular weight 25000). An ink was prepared using 5 parts and 2.5 parts of an acrylic resin (average molecular weight 50000).
Example 4
The organic solvent is 74.4 parts of BGAc, 3.8 parts of GBL, 14.0 parts of organic fluorescent pigment, 2.8 parts of pigment dispersant, and the vinyl chloride resin (average molecular weight 25000) is 1. An ink was prepared using 0 part and 4.0 parts acrylic resin (average molecular weight 70000).

(Comparative Example 1)
The organic solvent is 84.0 parts of BGAc, 3.8 parts of GBL, 7.0 parts of organic fluorescent pigment, 0.9 part of the pigment dispersant, and the vinyl chloride resin (average molecular weight 25000) is 1. An ink using 7 parts and 2.6 parts of an acrylic resin (average molecular weight 50000) was prepared.
(Comparative Example 2)
The organic solvent is 59.5 parts of BGAc, 3.8 parts of GBL, 30.5 parts of organic fluorescent pigment, 5.2 parts of pigment dispersant, and the binder resin is 0.1% of vinyl chloride resin (average molecular weight 25000). An ink was prepared using 5 parts of acrylic resin (average molecular weight 50000).
(Comparative Example 3)
The organic solvent is 77.8 parts BGAc, 3.8 parts GBL, 12.0 parts organic fluorescent pigment, 2.4 parts pigment dispersant, and vinyl acetate resin (average molecular weight 25000) is 4. binder resin. Ink was used for 0 parts.
(Comparative Example 4)
The organic solvent is 76.8 parts BGAc, 3.8 parts GBL, 12.0 parts organic fluorescent pigment, 2.4 parts pigment dispersant, 5.0 parts acrylic resin (average molecular weight 50000) as binder resin. The ink used was created.

(Comparative Example 5)
The organic solvent is 77.8 parts of BGAc, 3.8 parts of GBL, 12.0 parts of organic fluorescent pigment, 2.4 parts of pigment dispersant, and 4.0 parts of acrylic resin (average molecular weight 70000) as the binder resin. The ink used was created.
(Comparative Example 6)
The organic solvent is 78.2 parts of BGAc, 3.8 parts of GBL, 10.0 parts of the organic fluorescent pigment, 2.0 parts of the pigment dispersant, and the binder resin is 0.1% of vinyl chloride resin (average molecular weight 25000). An ink was prepared using 5.5 parts of 5 parts acrylic resin (average molecular weight 50000).
(Comparative Example 7)
The organic solvent is 79.7 parts of BGAc, 3.8 parts of GBL, 10.0 parts of the organic fluorescent pigment, 2.0 parts of the pigment dispersant, and the binder resin is 3. vinyl chloride resin (average molecular weight 25000). An ink was prepared using 5 parts and 1.0 part of an acrylic resin (average molecular weight 50000).
(Comparative Example 8)
The organic solvent is 76.8 parts BGAc, 3.8 parts GBL, 12.0 parts organic fluorescent pigment, 2.4 parts pigment dispersant, 2.5 parts binder resin is acrylic resin (average molecular weight 50000) An ink using 2.5 parts of acrylic resin (average molecular weight 70000) was prepared.

  The inks for inkjet recording obtained in Examples 1 to 4 and Comparative Examples 1 to 8 described above were subjected to a visibility test, a blocking test, a chemical resistance test, a physical resistance test, a gloss test, and an ink storage stability. A test and a continuous discharge performance test were conducted. The test results were evaluated according to the following criteria. The evaluation results are as shown in Table 2.

<Visibility test>
The inkjet recording ink was applied to a PVC substrate using a No. 6 Mayer bar (manufactured by RD Specialties) and dried at 25 ° C. for 2 days. Visibility of the dried coated surface was visually evaluated using a 3M Scotchcal fluorescent film series (manufactured by Sumitomo 3M) as a comparative control. The results are classified as follows and shown in the table.
○: Visibility equivalent to or better than that of the comparative control product was obtained.
X: Visibility equivalent to that of the comparative control product could not be obtained.

<Blocking test>
The inkjet recording ink was applied to a PVC substrate using a No. 6 Mayer bar (manufactured by RD Specialties) and dried at 25 ° C. for 2 days. The dried coated surfaces were cut into squares of 1 square centimeter, the coated surfaces were overlapped, and allowed to stand for 1 day under a weight of 500 g. After being allowed to stand, the overlapped coated surface was peeled off, and the presence or absence of peeling of the coated surface was evaluated. The results are classified as follows and shown in the table.
○: No peeling of the coated surface was observed.
X: Peeling of the coated surface was observed.

<Chemical resistance test>
The inkjet recording ink was applied to a PVC substrate using a No. 6 Mayer bar (manufactured by RD Specialties) and dried at 25 ° C. for 2 days. The dried coated surface was rubbed 20 times with a cloth soaked with the following chemicals, and the coated surface was visually evaluated. The chemicals used for resistance evaluation are 50% ethanol aqueous solution, neutral detergent, alkaline detergent, oxygen bleach, and chlorine bleach. The results are classified as follows and shown in the table.
○: No abnormality in the coated surface was confirmed for all chemicals.
(Triangle | delta): The abnormality of the coating surface was confirmed with some chemicals.
X: Abnormality of the coated surface was confirmed for all chemicals.

<Physical resistance test>
The inkjet recording ink was applied to a PVC substrate using a No. 6 Mayer bar (manufactured by RD Specialties) and dried at 25 ° C. for 2 days. Resistance of the dried coated surface was evaluated by the following test method. The test methods used were a rubbing test in which the coated surfaces were rubbed 50 times with a test cloth piece (for JIS dyeing fastness test), a cross-cut test on the coated surface, a bending resistance test for bending the coated surfaces, and 50 times between coated surfaces. This is a rubbing resistance test. The results are classified as follows and shown in the table.
○: The coated surface did not peel off by any method.
Δ: The coated surface was peeled off by several methods.
X: The coated surface was peeled off by all methods.

<Glossiness test>
The inkjet recording ink was applied to a PVC substrate using a No. 6 Mayer bar (manufactured by RD Specialties) and dried at 25 ° C. for 2 days. The dried coated surface was measured for gloss at a measurement angle of 60 ° using a gloss meter micro-TRI-gloss manufactured by BYK-Gardner. The results are classified as follows and shown in the table.
○: The glossiness was 60 or more.
Δ: Glossiness was 20 or more and less than 60.
X: The glossiness was less than 20.

<Ink storage stability test>
The ink for inkjet recording was stored at 60 ° C. for 4 weeks and at −15 ° C. for 4 weeks, and the viscosity before and after storage was measured to calculate the rate of change. The viscosity of the ink for inkjet recording was measured with a viscometer VISCOMETER TV-33 manufactured by Toki Sangyo Co., Ltd. The results are classified as follows and shown in the table.
A: Viscosity change rate before and after storage at 60 ° C. and −15 ° C. was less than ± 5%.
Δ: One of the rate of change in viscosity before and after storage at 60 ° C. and −15 ° C. was less than ± 5%.
X: Viscosity change rate before and after storage at 60 ° C. and −15 ° C. was ± 5% or more.

<Continuous printability test>
The ink for inkjet recording was evaluated for continuous printing performance using an inkjet recording apparatus IP-5620 (manufactured by Seiko I Infotech). An evaluation image of 6.0 meters was continuously printed in the normal density normal mode and the normal density and high density high-quality modes, and the nozzle omission (presence of non-ejection nozzles) before and after printing was measured. The measurement environment was evaluated under three environments of room temperature 15 ° C. and humidity 30%, room temperature 23 ° C. and humidity 50%, and room temperature 30 ° C. and humidity 70%. The results are classified as follows and shown in the table.
○: No missing nozzle was observed before and after printing under each environment.
Δ: Nozzle missing was observed before and after printing under some circumstances.
X: Nozzle omission was observed before and after printing under all circumstances.

Here, an Example and a comparative example are compared.
It can be seen that Comparative Example 1 has poor visibility because the organic fluorescent pigment concentration in the ink is less than 8% by weight. Furthermore, since the pigment dispersant concentration in the ink is less than 1% by weight, it can be seen that the storage stability of the ink is poor.

In Comparative Example 2, since the concentration of the organic fluorescent pigment in the ink exceeds 30% by weight, the amount of the binder resin added is suppressed when prepared and used in a viscosity that can be ejected from the recording head. It can be seen that the ink storage stability and the continuous printability test are poor. Further, since the concentration of the pigment dispersant in the ink exceeds 5% by weight, it can be seen that the printed matter has poor blocking properties and chemical resistance.
Since the comparative example 3 does not use together the acrylic resin which used methyl methacrylate and butyl methacrylate as a structural monomer for binder resin, it turns out that blocking property is unsatisfactory.
Since the comparative example 4 does not use vinyl chloride resin together with binder resin, it turns out that chemical resistance, physical resistance, and continuous printability are unsatisfactory.

Since Comparative Example 5 does not use a vinyl acetate resin in combination with the binder resin, it can be seen that the chemical resistance, physical resistance, and continuous printability are poor.
It can be seen that Comparative Example 6 has poor chemical resistance, physical resistance, and continuous printability because the ratio of vinyl chloride resin and acrylic resin, which is a binder resin, is less than 0.1.
Since the ratio of the vinyl chloride resin which is binder resin and an acrylic resin exceeds 3.0, the comparative example 7 turns out that blocking property is unsatisfactory.
Since Comparative Example 8 does not use a vinyl acetate resin in combination with the binder resin, it can be seen that the chemical resistance, physical resistance, and continuous printability are poor.

  In Example 1, the content of the organic fluorescent pigment is 12.0% by weight, and the binder resin is used in combination with a vinyl acetate resin, an acrylic resin having methyl methacrylate and butyl methacrylate as constituent monomers, Since the ratio of the acrylic resin is 0.65, it can be seen that good results are obtained in all the tests of visibility, blocking property, chemical resistance, physical resistance, glossiness, ink storage stability, and continuous printability.

  In Example 2, the content of the organic fluorescent pigment is 10.0% by weight, and the binder resin is used in combination with a vinyl acetate resin, an acrylic resin having methyl methacrylate and butyl methacrylate as constituent monomers, Since the ratio of the acrylic resin is 0.2, it can be seen that good results are obtained in all tests of visibility, blocking property, chemical resistance, physical resistance, glossiness, ink storage stability, and continuous printability.

  In Example 3, the content of the organic fluorescent pigment was 14.0% by weight, and the binder resin was used in combination with a vinyl acetate resin, an acrylic resin having methyl methacrylate and butyl methacrylate as constituent monomers, Since the ratio of the acrylic resin is 0.25, it can be seen that good results are obtained in all tests of visibility, blocking property, chemical resistance, physical resistance, glossiness, ink storage stability, and continuous printability.

  In Example 4, the content of the organic fluorescent pigment was 12.0% by weight, and the binder resin was used in combination with a vinyl chloride resin, an acrylic resin having methyl methacrylate and butyl methacrylate as constituent monomers, Since the ratio of the acrylic resin is 0.25, it can be seen that good results are obtained in all tests of visibility, blocking property, chemical resistance, physical resistance, glossiness, ink storage stability, and continuous printability.

From the above, it can be seen that the content of the organic fluorescent pigment is preferably 8 or more and 30% by weight or less.
Furthermore, when only a vinyl chloride resin is used as the binder resin, the concentration of the organic fluorescent pigment in the ink is high, and therefore, when the necessary binder resin is added to ensure sufficient adhesion with the recording base, It can be seen that the viscosity of the recording ink increases and it is difficult to obtain a stable ejection performance from the recording head. Further, when the viscosity is adjusted so as to be ejected from the recording head, it is understood that a sufficient amount of the binder resin cannot be added to the ink, and the adhesion to the recording substrate becomes insufficient.

Furthermore, when only an acrylic resin having methyl methacrylate and butyl methacrylate as constituent monomers is used, not only the adhesion to the recording substrate and the chemical resistance cannot be sufficiently obtained, but also the solid content concentration in the ink is low. It becomes high and it becomes difficult to obtain the stable discharge performance from a recording head.
Furthermore, it turns out that it is preferable to use together a vinyl chloride resin and the acrylic resin which used methyl methacrylate and butyl methacrylate as a structural monomer for binder resin.

  By comparing the results shown in Table 2, the organic fluorescent pigment is dissolved in the ink for inkjet recording, and the binder resin is a combination of vinyl chloride resin and acrylic resin having methyl methacrylate and butyl methacrylate as constituent monomers. By doing so, it can be seen that an inkjet recording ink and an ink cartridge having the safety, storage stability, stable ejection performance from the recording head, and drying of printed matter can be provided.

  Here, a recording method by the ink jet recording apparatus will be described. A shuttle type ink jet recording apparatus is used in which a recording head is mounted on a carriage that reciprocates in the main scanning direction over the recording substrate, and recording is performed by a plurality of scans. For example, when recording is performed by four scans, the recording base is transported in the sub-scanning direction for each quarter width of the recording head, and after each transport, ink is ejected, so that the nozzle is located at the same position on the recording base. Can be discharged four times.

  First, ink is ejected onto the recording substrate while the carriage is scanned in the main scanning direction. Next, the recording substrate is moved in the sub-scanning direction by a quarter width of the recording head, and ink is ejected onto the recording substrate while scanning the carriage in the main scanning direction. Ink can be ejected to the same position up to four times in one scan. That is, recording can be performed at a high density, the visibility is excellent, and the organic fluorescent pigment is fixed thickly, so that the light resistance is also increased.

  The present invention can be suitably applied to ink for inkjet recording.

1 Ink cartridge 2 Pouch 3 Upper case 4 Lower case 5 Ink outlet

Claims (10)

  An inkjet recording ink comprising an organic fluorescent pigment, a pigment dispersant, an organic solvent, and a binder resin, wherein the organic fluorescent pigment is a synthetic resin dyed with a dye, and the binder resin is a salt vinegar The ratio of the vinyl chloride resin and the acrylic resin in the inkjet recording ink is 0.1 ≦ ((weight% of the vinyl chloride resin) / (weight of the acrylic resin). %)) ≦ 3.0 and the content of the binder resin in the inkjet recording ink is 1% by weight or more and 20% by weight or less. .   2. The ink for ink jet recording according to claim 1, wherein the content of the organic fluorescent pigment in the ink for ink jet recording is 8 wt% or more and 30 wt% or less.   3. The ink for ink jet recording according to claim 1, wherein the content of the pigment dispersant in the ink for ink jet recording is 1 wt% or more and 5 wt% or less.   The ink for ink jet recording according to any one of claims 1 to 3, wherein the acrylic resin is an acrylic resin having methyl methacrylate and butyl methacrylate as constituent monomers. The organic fluorescent pigment includes at least one of a polyamide resin, a formaldehyde polycondensate, a ketone resin, and a vinyl copolymer as the synthetic resin, and at least one of an oily dye and a basic dye as a colorant for the synthetic resin. The ink for ink-jet recording according to any one of claims 1 to 4, characterized by comprising 6. The pigment dispersant according to claim 1, wherein the pigment dispersant contains a polyalkyleneimine dispersant or a basic dispersant having an amine value of 10 mgKOH / g or more and 50 mgKOH / g or less. The ink for inkjet recording as described. An ink for inkjet recording according to any one of claims 1 to 6,
An ink cartridge comprising: a pouch for storing the ink for ink jet recording; and a case for storing the pouch. An inkjet recording ink manufacturing method comprising an organic fluorescent pigment, a pigment dispersant, an organic solvent, and a binder resin, wherein the organic fluorescent pigment is a synthetic resin dyed with a dye, and the binder resin Contains vinyl chloride resin and acrylic resin,
Dissolving the organic fluorescent pigment and the pigment dispersant in the organic solvent to obtain a pigment dispersion;
The ratio of the vinyl chloride resin and the acrylic resin in the ink for ink jet recording is 0.1 ≦ ((wt% of the vinyl chloride resin) / (wt% of the acrylic resin)) ≦ 3.0 The pigment dispersion, the binder resin, and the organic solvent are mixed so that the content of the binder resin in the inkjet recording ink is within the range represented by the formula, and is 1 wt% or more and 20 wt% or less. And a process for producing an ink for ink-jet recording, comprising the step of: Storing the ink for inkjet recording according to any one of claims 1 to 6 in a pouch;
And a step of storing the pouch in a case. In a recording method of an ink jet recording apparatus that ejects ink for ink jet recording while scanning a recording head having a plurality of nozzles in the main scanning direction of the recording substrate,
The inkjet recording ink is the inkjet recording ink according to any one of claims 1 to 6,
A step of discharging the ink for ink jet recording onto a recording substrate by a first scan, a step of conveying the recording substrate in a sub-scanning direction,
In the second scan after the first scan, the inkjet recording ink is ejected onto the recording substrate by the first scan by a nozzle other than the nozzle used in the first scan. And a step of discharging ink for inkjet recording.

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