JPH03200883A - Ink composition for ink jet recording - Google Patents

Abstract

PURPOSE:To obtain the title composition improved in storage stability, delivery stability, delivery response, definition of an image, water resistance, and light resistance by compounding a specified dye mixture, a water-soluble organic solvent, and water as principal components. CONSTITUTION:A dye of formula I [wherein CuPc is a copper phthalocyanine skeleton; (n) is 2 to 4; M is H, an alkali metal or (organic) ammonium] is mixed with a dye of formula II (wherein (p) is 1 to 2, and (q) is 1 to 3, provided that 2<=p+q<=4) so as to provide a mixture shown by formula III, wherein the average number (l) of sulfonamide groups per molecule is 0.1 to 0.95 and the average number (m) of sulfo groups per molecule is 2 to 3.5, provided that 2.4<=l+m<=4, thus giving a dye mixture. 0.5-15wt.% dye mixture thus obtained and 4-50wt.% water-soluble organic solvent (e.g. ethylene glycol) are dissolved in water to give the title composition having a viscosity of 1.2-7.0cPs, a surface tension of 30-60dyne/cm, and a pH of 4 to 11.

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to an ink composition for inkjet recording.

More specifically, the present invention relates to an ink composition for inkjet recording that has excellent storage stability, ejection stability, ejection response, image clarity, light resistance, etc. in inkjet recording.

<Prior Art> Usually, an aqueous inkjet recording ink composition is basically composed of a dye, an organic solvent, and water, but in order to perform good inkjet recording, it is necessary to Various conditions are required.

First, the physical properties of ink depending on the droplet generation method and droplet flight direction control method include ink viscosity, surface tension, specific conductivity,
It is necessary that specific gravity, pH, etc. are within appropriate ranges.

Furthermore, during long-term storage, long-term use, or recording suspension, no precipitates should be generated due to chemical or physical changes, and the physical properties of the ink should not change. The ejection nozzle of a recording device generally has a diameter of about 10 to 60 μm, and if the nozzle is completely clogged with deposits, droplets cannot be ejected. Even if the nozzle is not completely clogged, if solid matter or sticky matter adheres to the vicinity of the nozzle, or if the physical properties of the ink that were adjusted to desired values during ink formulation change, recording performance, ejection stability, and ejection response may deteriorate. descend.

The recorded image has sufficiently high contrast,
Of course, it is also required that the image is clear and has water resistance, light resistance, etc.

<Problems to be Solved by the Invention> Conventionally, copper phthalocyanine derivatives, which are relatively excellent in light fastness, color tone, water resistance, etc., have been used as blue dyes for water-based inks. For example, C,1,direct
Blue 86, -199, C0! , acid blue 24
9 and the dyes described in JP-A-62-190273 are known.

However, when these copper phthalocyanine derivatives are used as inkjet inks, for example, the dye may coagulate and precipitate during storage or use, causing nozzle clogging, or water may evaporate at the nozzle tip when left for a long period of time.
There are disadvantages such as dye precipitation and nozzle clogging.

In other words, when these copper phthalocyanine derivatives are used as inkjet inks, they have some drawbacks in terms of storage stability, ejection stability, ejection response, image clarity, light resistance, etc., and cannot meet all conditions as inkjet inks. The reality is that nothing that satisfies these requirements has yet been found.

The present inventors have completed the present invention as a result of intensive studies to improve these conventional problems.

Means for Solving the Problems> In an inkjet recording ink composition containing a dye, a water-soluble organic solvent, and water as main components, the general formula (I) Cu P c-(S Os M) n (
I) (CuPc represents a copper phthalocyanine skeleton, n represents an integer of 2 to 4, and M represents a hydrogen atom, an alkali metal, ammonium or organic ammonium.

) and the general formula (I[) (where CuPc represents a copper phthalocyanine skeleton, M
represents a hydrogen atom, an alkali metal, ammonium or organic ammonium, p represents an integer of 1 to 2, and q represents 1
Represents an integer from ~3. However, it is a mixture of dyes expressed as 2≦1)+(1≦4), where the average number of sulfonamide groups per molecule is l, and the average number of sulfonic acid groups is When expressed as m, - general formula (I[) (where CuPc represents a steel phthalocyanine skeleton, M
represents a hydrogen atom, an alkali metal, ammonium or organic ammonium), l is a real number from 0.1 to 0.95, and m
is a real number from 2 to 3.5, and the relational expression between l and m is 2.
The present invention is an inkjet recording ink composition characterized by using a mixed dye satisfying 4≦l+m<4.

The dye used in the present invention is a mixture of the dye represented by the general formula (I) and the dye represented by the general formula (II), and when expressed as the general formula (I[), 1 It is characterized in that m represents a predetermined number. Therefore, if this condition is not met, there will be some drawbacks in the storage stability, ejection stability, ejection response, image clarity, light resistance, etc. that are the objectives of the present invention. For example, when a mixed dye is expressed as -mona (III), l
If it is less than 0.1, the water resistance, light resistance, and image density will be poor, and the stability of the ink will be reduced. On the other hand, l is 0.
If it exceeds 95, the water resistance, light resistance and image density are good, but the solubility of the dye becomes poor and the storage stability of the ink deteriorates.

Specific examples of the dye represented by the general formula (I) used in the present invention include the following.

1 1 CuPc-(-3OsNa)tl
2CuPc-+SOsNa)2CuPc
−←5O1 Na) CuPc−←5O3 H) CuPC−+503NH(CHtCHtOH)s)Cu
Pc-(S0xNH.

) CuPc-+SO! Hs ) CuPc-←sow NH.

) Further, specific examples of the dye represented by the general formula (n) used in the present invention include the following.

CuPc-←5O2 H) Cu P c -+S, O5 H) CuPc-←5O3 Cu P c -(S O2 CuPc-←S Oa CuPc-←5O3 K) CuPc-←S O5 K) CuPc-←S O5 CuPC -G-3O! NH(CHtCHtOH)i)C
uPC+SO! NH(CHtCHtOH)*) Table-1 The dyes represented by the general formula (II[) of the present invention include:
The mixed dye obtained by mixing the dyes represented by the general formula (I) and the general formula (n) may be any dye as long as it is included in the general formula (III), but particularly preferably 1 m is 0.3 to 0.6, m is 2.0 to 3.0, and specific examples include the mixed dyes shown in Table 1 below.

The dye represented by the general formula (1) used in the present invention can be easily produced by a method known per se.

Furthermore, the dye represented by the general formula (n) used in the present invention can be obtained by, for example, chlorosulfonating copper phthalocyanine using thionyl chloride in chlorosulfonic acid, then amidating it with ammonia, and reacting it with amines if necessary. Therefore, it can be easily manufactured.

In addition, when these dyes are obtained as a mixture, they are fractionated using a column or the like, if necessary. Further, these dyes can be identified by means known per se, such as NMR and IR.

The content of the above-mentioned mixed dye in the ink composition is determined depending on the type of liquid medium component, the properties required of the ink, etc., but is generally 0.5% by weight based on the total weight of the ink. It is used in a range of 15% to 15%, preferably 2 to 10%. In addition to this dye as an essential component, various dyes such as other direct dyes and acid dyes can be used in combination.

Examples of water-soluble organic solvents used in the present invention include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, 1,4-butylene glycol, and 2.3-butylene glycol. , glycerin,
Diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol isopropyl ether, propylene glycol-n-butyl ether, dipropylene glycol monomethyl ether, dipropylene Glycol-n-butyl ether, dipropylene glycol isopropyl ether, tripropylene glycol monomethyl ether,
Examples include tribropylene glycol monoethyl ether, tripropylene glycol-n-butyl ether, glycerin-α, γ-dimethyl ether, and glycerin α-mono-butyl ether, and one or more of these may be appropriately selected and used. The amount added is generally 4 to 50%. Also, generally the viscosity of the ink is 1.2 to 7.0.
cps, surface tension is 30-60 dyne/cm,
The pH is adjusted to 4-11.

In addition, the ink according to the present invention may contain monoethanolamine, jetanolamine, etc. to an extent that does not impair its properties.
Alkanolamines such as triethanolamine, di-1sO-propertoolamine; methanol, ethanol, n-propertool, n-butanol, 1sO-butanol, 5ec-butanol, te
rt-butanol, n-amyl alcohol, 1so-amyl alcohol, 2-methyl-1-butanol 2-pentanol, 3-pentanol, 2-methyl-2-butanol, amylcarbinol, methylisobutylcarbinol, ethylbutanol , heptatool, methylamylcarbinol, alcohols such as ethylbutyl alcohol; sodium dehydroacetate, 4-chloro-3-ethylphenol, hexahydro-1,3,5-)lis(2-
A fungicide such as (hydroxyethyl)-1,3,5-triazine can be used.

Effects> The inkjet recording ink composition according to the present invention has excellent storage stability, ejection stability, ejection response, image clarity, light resistance, and the like.

<Examples> Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples in any way.

Example! Mixed dye (1) 5 parts by weight Polyethylene glycol 200 10 parts by weight Diethylene glycol 15 parts by weight Ion exchange water
70 parts by weight 4-chloro-3-ethylphenol 0.02 parts by weight The above components were thoroughly mixed and stirred in a container, and filtered through a 0.degree. 2.mu. membrane filter to prepare an ink.

Using the obtained ink, print an inkjet printer (
The following studies (a) to (d) were conducted using a model IJK-112 (manufactured by Chinon Co., Ltd.), and good results were obtained in all cases.

(a) Clogging at the tip of the nozzle The nozzle head was filled with ink and left at 60° C. for one week, and then the ejection condition was observed. There was no clogging, and stable and uniform recording was achieved.

(b) Storage stability of recording liquid Even after the recording liquid was sealed in a glass container and stored at 0°C and 60°C for one month, no precipitation of insoluble matter was observed, and there was no change in the physical properties or color tone of the liquid. .

Continuous ejection was performed for 24 hours in an atmosphere of room temperature, 5° C., and 40° C., and stable high-quality recording was possible from beginning to end under all conditions.

(d) Ejection responsiveness After the ejection was completed, the state of re-ejection after being left for one month was investigated, and the recording was stable and uniform with no clogging at the tip of the orifice.

Examples 2 to 13, Comparative Examples 1 to 10 According to the method of Example 1, a recording liquid having the composition shown in Table 1 below was prepared, and (a) to (d) described in Example 1 were prepared.
The results of the evaluation according to the method are shown in Table 2.
All of the samples according to Examples were good.

(Margin below) (c) Discharge stability

Claims (1)

[Claims] In an inkjet recording ink composition containing a dye, a water-soluble organic solvent, and water as main components, the general formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (However, CuPc Represents a copper phthalocyanine skeleton, n
represents an integer from 2 to 4, and M represents a hydrogen atom, an alkali metal, ammonium or organic ammonium. ) Dye represented by the general formula (II) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(II) (However, CuPc represents a copper phthalocyanine skeleton, and M
represents a hydrogen atom, an alkali metal, ammonium or organic ammonium, p represents an integer of 1 to 2, and q represents 1
Represents an integer from ~3. However, 2≦p+q≦4. ), where the average number of sulfonamide groups per molecule is l and the average number of sulfonic acid groups is m, the general formula (III) ▲ Formula , chemical formulas, tables, etc.▼(III) (However, CuPc represents a copper phthalocyanine skeleton, and M
represents a hydrogen atom, an alkali metal, ammonium or organic ammonium), l is a real number from 0.1 to 0.95, and m
is a real number from 2 to 3.5, and the relational expression between l and m is 2.
An inkjet recording ink composition characterized in that it uses a mixed dye satisfying 4≦l+m<4.