JPH05214261A - Water-soluble organic dye and ink jet for ink jet printer - Google Patents

Abstract

PURPOSE: To provide a dye and ink not reduced in its color intensity for an ink jet printer using such dye and having water solubility and excellent water- resistant fastness.

CONSTITUTION: A water-soluble dye is selected from respective dyes of azo, triphenylmethane, anthraquinone, methine, xanthine, azine, oxazine, thiazine, thiazole, quinoline, aminoketone, nitro, nitroso, phthalocyanine, acridine, indamine and indophenol and has at least one boric acid group on an aryl radical. Ink for an ink jet printer consists of about 0.05-10% of the above mentioned dye (a), a pH controller (b) holding the pH of a compd. to about 6-9 and the remainder of water (c).

COPYRIGHT: (C)1993,JPO

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention is in the field of water-soluble dyes such as azo dyes, where at least one on the aryl ring.
It relates to novel dyes having two boric acid groups. The invention also relates to the use of these dyes in inks for inkjet printers.

[0002]

BACKGROUND OF THE INVENTION The use of inkjet printers and the formulation of special inks for printing on paper or similar materials are
It has been the subject of intensive research over the last few years. Dyes have often provided the coloring component in such inks.
Water-soluble dyes have been used because these inks are usually water-based. Examples of these dyes include azo dyes, anthraquinone dyes, methine dyes, xanthine dyes, oxazine dyes and thiazine dyes. Water solubility has been provided by sulfonic acid groups or salts thereof attached to at least one aryl component of the dye. However, when the sulfonic acid group is attached to the aromatic ring, the resonance also induces an inductive interaction.
ration) is also close to zero. Further, when the sulfonic acid group is arranged adjacent to the azo group, the color intensity is slightly reduced due to the steric interaction with the azo group. Furthermore, the sulfonate groups contribute to solubility but not to waterfastness. For this reason, research into other dyes that can be used in inkjet printers continues.

[0003]

OBJECT OF THE INVENTION The present invention is directed to at least one aryl ring.
Novel water-soluble organic dye having two boric acid groups, and
It is an object of the present invention to provide an ink for an inkjet printer, which is free from reduction in color strength, is water-soluble, and is excellent in water fastness using these dyes.

[0004]

SUMMARY OF THE INVENTION The present inventors have discovered a new class of dyes, including azo dyes, which are specifically utilized in ink jet printing inks. These new dyes have at least one boric acid moiety on the aryl ring and are represented by the formula

[0005]

[Chemical 2]

In the formula of formula 2, D is an organic dye moiety, X is hydrogen, or a cation in a basic solution, such as Na, K, Li or NH _y (CH ₃ ) _z ,
y and z each range from 0 to 4, and the sum of y and z equals 4. The boric acid group is a reactive group for imparting water solubility to the dye and binding the dye to the substrate.

[0007]

EXAMPLES The present invention includes azo dye, triphenylmethane dye, anthraquinone dye, methine dye, xanthene dye, azine dye, oxazine dye, thiazine dye, thiazole dye, quinolinone dye, aminoketone dye, nitro dye, nitroso dye, phthalocyanine. Includes dyes, acridine dyes, indamine dyes and indophenol dyes. Next, as a representative, an azo dye will be described as a reference.

The novel monoazo compounds of the present invention can be prepared according to the formula: In this formula, A
r and Ar ₁ are arylene or substituted arylene, and n is an integer of 1-2.

[0009]

[Chemical 3]

The polyazo dye is prepared as shown below. In this formula, the electron-donating group of Ar ₂ facilitates the coupling reaction. Ar ₂ is diazotizable NH ₂
A new azo compound may be added as long as it has a substituent.

[0011]

[Chemical 4]

The polyazo dye corresponds to the structure of Chemical formula 5.
In this formula, m is an integer from 1 to about 4.

[0013]

[Chemical 5]

The coupling reaction produces a mixture of ortho and para isomers in the phenylene system. In the naphthalene system, a mixture of α and β isomers is obtained. The ratio of α isomer to β isomer is p
It can be adjusted by controlling H.

There are several published methods for preparing aromatic boric acid compounds used as starting materials for preparing the dyes of this invention. These methods are not very complicated. For example, arylboronic acids are readily synthesized from several types of organometallic compounds including aryllithium compounds and Grignard reagents. Regarding the latter, Organometallic Chemistry, Vol. 259, 1983, No.
George W., p. 3, 269-274. See the paper by Kabarka and others.

The dye of the present invention has a plurality of boric acid groups. Boric acid groups on both ends of the molecule are particularly useful.

Boric acid compounds are generally considered to be hydrolytically unstable in aliphatic compounds, but when used directly in aryl groups for use in ink jet dyes. It has sufficient stability.
These compounds also have excellent water solubility and color, and the inks containing these compounds can print well on paper.

The dye of the present invention is preferably represented by the formula (6).

[0019]

[Chemical 6]

In this formula, Ar is a phenylene group or a substituted phenylene group, and Ar ₁ is hydroxyphenylene, aminophenylene, N, N-di- (lower alkyl) -aminophenylene, bromophenylene, chlorophenylene, lower alkylphenylene. , Nitrophenylene, naphthalene, hydroxynaphthalene, chloronaphthalene, bromonaphthalene, nitronaphthalene, aminonaphthalene, N, N-di- (lower alkyl) -aminonaphthalene, methoxyphenylene and lower alkylnaphthalene. or a substituted arylene group, Ar ₂ is hydroxyphenyl, aminophenyl, hydrido alkoxy aminophenyl, N, N-di (lower alkyl) - amino phenyl, N, N-di (lower alkyl) - Aminoka Voxyphenyl, bromophenyl, chlorophenyl, lower alkylphenyl, nitrophenyl, hydroxynitrophenyl, hydroxycarboxylphenyl, carboxyl acrylamidophenyl, succinimidophenyl, tetrahydrocarboxymethylphthalimidophenyl, naphthyl, hydroxynaphthyl, chloronaphthyl, bromonaphthyl, nitronaphthyl, hydroxy. Nitronaphthyl, aminonaphthyl,
Aryl selected from the group consisting of N, N-di (lower alkyl) aminonaphthyl, lower alkylnaphthyl, hydroxyaminonaphthyl, dihydroxyaminonaphthyl, hydroxydiaminonaphthyl, hydroxycarboxynaphthyl, hydroxyaminoquinolyl and aminomethoxydibenzofuranyl. A group or a substituted aryl group, m
Is 0 or an integer of 1 to about 4, and n is an integer of 1 to 2.
The substituents on the naphthyl ring include one or both of the α and β positions. It is desirable that Ar ₁ and Ar ₂ have no sulfonate group.

In the chemical formula 6, (a) n is 1, (b) m is 0, 1 or 2.
(C) Ar ₂ is 2 B _(HO) ^- be substituted by,
(D) Ar is a phenylene group, Ar ₂ is hydroxyphenyl, m is 0 and n is 1, (e) Ar is a phenylene group, Ar ₂ is aminohydroxyphenyl,
m is 0 and n is 1, (f) Ar is a phenylene group, Ar ₁ is naphthalene, Ar ₂ is 2-aminophenyl-4-boric acid, m is 1 and n is 1 Is preferred.

The dye of the present invention is excellent for inkjet printing for the following reasons.

(1) Due to the low acidity of the boric acid groups, ie the low pKa value, these dyes are protonated to undissociated acids at neutral pH, which when printed on paper naturally. Solubility decreases due to neutralization.

(2) The boric acid group forms a strong permanent bond with cis-diols such as are present in sugar, starch and cellulose. For example, since paper contains starch and cellulose, these dyes produce strong permanent bonds to the paper. Also, these dyes are used to dye cellulosic fibers such as cotton.

(3) In the presence of alcohol, the aryl boric acid group forms an ester and reduces the solubility of the boric acid group. Upon the disappearance of water when the ink starts to dry immediately after being printed on paper, the boric acid group condenses with the alcohol group, and (a) a polyol group bonded to the other end of the dye molecule, or ( b) There is the possibility of developing a reaction which forms a polymerizable ester bond with the polyol added to the ink solution. The at least one boric acid dye then binds to the polyol to form a dye-polyol polymer with reduced solubility on paper. When these dyes are fed to the paper from an inkjet printer, the dyes are completely waterfast. This kind of reaction
Arylboric acid and cis-1,2 and cis-1,3-
Spontaneous with cis-diols such as diols to the extent that they immediately form reaction products in solution.

One method of practicing the present invention is to use a diol or alcohol mixture, in which the functionality of the aryl boric acid is not preferred for ester formation which occurs in dilute solutions such as inks. It causes the insolubilization of ester bonds in a highly concentrated solution that occurs upon evaporation of the ink on the paper. The slightly basic ink, which has undergone natural neutralization on the paper surface, is also the driving force for this condensation or polymerization reaction. Although in theory the reaction is reversible, the short time involved in events such as print smearing and raindrops on the printing surface does not provide enough time and concentration to reverse the reaction. Therefore, the printing on paper appears to be stain resistant and waterfast.

Usually, cis-diols form a highly sterically preferred five-membered ring with aryl boric acid groups. The method of the present invention is to include an aryl borate group in the less preferred 6-membered or 7-membered diol ester ring by using 1,3-diol even in the case of an open chain ester. Larger thermodynamically less favorable cyclic esters have an unfavorable equilibrium in dilute solutions but form when the ink is dried and concentrated. Natural neutralization and possible printer dryer heat are the new driving forces for condensation or polymerization.

(4) A major significant advantage for arylboronic acid as a dye solubilizing group is the ability of the boron atom to interact with the chromophore. Boron has an empty p-orbital of suitable size and shape to maximize the interaction of the dye molecule with the aryl ring. The borate group acts as an electron-withdrawing group to stabilize the charge transfer excited state and stabilizes the resonance contribution of the electron-donating group in other parts of the chromophore. All of these contribute to the bathochromic migration within the dye molecule.

For example, a simple aryl monoazo compound itself is slightly colored, and the presence of electron donating and accepting groups causes strong dark and deep chromophore migration to the arylazo compound. Bring The boric acid groups are strong accepting groups and therefore a very significant advantage for these groups in arylazo dyes is an increase in color strength or color strength (also blackness), and of simple azo compounds. This is a contribution to the ability to move the wavelength to the longer wavelength absorption side.

The significance of this advantage can be better understood when the aryl sulfonate group realizes that the resonance and inductive interactions are close to zero when directly attached to the aromatic ring. Furthermore, due to the large size of the aryl sulfonate group, when adjacent to the azo group in the same ring, the strength of the dye is slightly impaired due to steric interaction with the azo group. Result. For example, aryl boric acid dyes offer significant advantages over the current selection of sulfonated dyes, especially sulfonated azo dyes.

The boric acid dyes of the present invention can generally be used in ink formulations for ink jet printers in place of the currently used sulfonate azo dyes.

The preferred ink formulation is (a) about 0.0.
It contains 5-10% dye, (b) sufficient pH adjuster to maintain the formulation at a pH of about 6 to about 9, and (c) residual water.

Ink formulations generally contain up to about 20% organic solvent for the dye. Typical solvents are glycol, pyrrolidone, formamide, 2- (2-butoxyethoxy) ethanol (n-butylcarbitol), 1,5-pentanediol, 1,4-butanediol, and glycols and diglycols. Butoxy,
Ethoxy and methoxy half ether.

Buffering agents such as borates, ammonium salts, acetates, phosphates or tris (hydroxymethyl) aminomethane are used to adjust the pH of the ink. Additives normally found in thermal inkjet inks may be added to the inks of this invention. These additives include microbial poisons, wetting agents, surfactants and the like.

When the polyol or polyamine is mixed with an equimolar volume of dye, the hydroxyl or amine groups react with the boric acid groups of the dye. If the dye has at least two boric acid groups, a polymeric product can be formed.

The ink formulation of the present invention was prepared by
When used with Packard'DeskJet 'inkjet printers to print on paper, a sharp, permanent image is obtained.

The polyamine added to the boric acid dye is a unique compounding complex in that the boric acid dye forms a complex with the amine. The first set of boric acid dyes are overly soluble in dilute solutions, but the addition of polyamines to them significantly improves waterfastness. The complex is probably a simple salt formation.

Furthermore, when it is desired to avoid the addition of sulfonate groups, the addition of polyamines is a simple way to increase the solubility of boric acid dyes and the addition of multiple boric acid groups is too expensive.

The novel boric acid dyes and inks containing these dyes are expected to find use in ink jet printers.

[0040]

EXAMPLES The following examples are utilized to illustrate the present invention. Example 1 0.1 mol of 3-aminophenyl boric acid was added to the acid and 1.0
Diazotization with 5 mol sodium nitrite produced the diazonium intermediate. Then, this intermediate is
Coupling with 14 g of phenol at H8.5, the product obtained was a mixture corresponding to the formula In this formula, the hydroxyl group is in the ortho or para position to the azo bond. The main products obtained are:
It can be separated by high-performance liquid chromatography on a separation scale.

[0041]

[Chemical 7]

Example 2 The diazonium intermediate of Example 1 was coupled with N, N-dimethylaniline to produce the compound of formula The procedure of Example 1 was repeated.

[0043]

[Chemical 8]

Example 3 The diazonium intermediate of Example 1 was coupled with 2-naphthol to produce the compound of formula The procedure of Example 1 was adopted. The para isomer was the predominant product and the ortho isomer was the predominant product.

[0045]

[Chemical 9]

Example 4 The diazonium intermediate of Example 1 was coupled with 3-hydroxyaniline to produce a compound of formula The procedure of Example 1 was repeated.

[0047]

[Chemical 10]

Example 5 The diazonium salt of 3-aminophenylboronic acid was coupled with 1-aminonaphthalene. The product of this reaction was diazotized and coupled with 3-aminophenyl boric acid. The resulting dye corresponded to the formula

[0049]

[Chemical 11]

Example 6 A new dye can be made using standard diazotization procedures, in which Ar ₁ is a naphthyl group and Ar ₂ is a hydroxynaphthyl group. The hydroxyl group may be at the α position or the β position, and as long as the coupling occurs adjacent to the hydroxyl group, a good red dye is produced.

Example 7 The following experiment was conducted to compare the waterfastness of borated dyes with sulfonated dyes. An ink was made according to the formulation of Table 1 from two types of dyes having the structure of Chemical formula 12 except that one is X and the other is X, and X is sulfonic acid.

[0052]

[Chemical 12]

[0053]

[Table 1]

These inks were used in conventional ink jet printers to fill the pen of the printer and produce a print sample. Water resistance is
It measured as follows.

The checkerboard pattern of 1 inch square is
Alternately print 100% solid area and blank area,
Samples were obtained having a first row of blank-solid-blank squares, a second row of solid-blank-solid squares, and a third row of blank-solid-blank squares. One pattern was set aside as a standard. The other pattern was a 5 minute wash in deionized water with vigorous stirring. After the washed pattern had dried, the L *, a * and b * coordinates were measured for the standard and washed patterns and at least 4 patterns were averaged. ΔE was calculated as the color difference between the standard sample and the washed sample.

All color measurements were made with a 10 degree observer, D6
5 Illuminant, ASTM method D2
244 to 85, and the results shown in Table 2 were obtained.

[0057]

[Table 2]

The ΔE of the borated dye is in the order of magnitude better than the ΔE of the sulfonated dye. ΔE is
Better in the DEG system than in the 2-P system, a factor of 5.

Examples 8 to 26 The boric acid dyes shown in Tables 3 to 8 were prepared, in which m was 0 and n was 1.

[0060]

[Table 3]

[0061]

[Table 4]

[0062]

[Table 5]

[0063]

[Table 6]

[0064]

[Table 7]

[0065]

[Table 8]

Inks prepared from the dyes of Examples 1-6 and 8-26 are expected to exhibit the same type of behavior observed for the inks discussed in Example 7.

As described above, at least 1 is contained in the aryl group.
Water-soluble organic dyes with two boric acid groups have been disclosed. Various modifications and alterations of the obvious nature can be made without departing from the spirit of the invention, and all such modifications and alterations fall within the scope of the invention as defined by the claims. It will be obvious to a person skilled in the art.

[0068]

As described in detail above, the dye of the present invention is
Since it is sulfonate-free, it does not reduce the color strength, and it is also water-soluble and has excellent waterfastness. Further, according to the ink for an inkjet printer of the present invention using such a dye of the present invention, it is possible to provide printing of excellent quality.

Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location C09D 11/00 PSZ 7415-4J

Claims (3)

[Claims] 1. An azo dye, a triphenylmethane dye, an anthraquinone dye, a methine dye, a xanthene dye, an azine dye, an oxazine dye, a thiazine dye, a thiazole dye, a quinolinone dye, an aminoketone dye, a nitro dye,
Nitroso dye, phthalocyanine dye, acridine dye,
A water-soluble organic dye having at least one boric acid group on an aryl radical selected from the group consisting of indamine dyes and indophenol dyes. 2. An azo dye having the formula: [Chemical 1] In this formula, Ar is a phenylene group or a substituted phenylene group, Ar ₁ is an arylene group or a substituted arylene group without a sulfonate group, Ar ₂ is an aryl group or a substituted aryl group without a sulfonate group, and m is 0 or 1 to about 4 An integer and n is an integer of 1 to 2. 3. (a) about 0.05-10% of a water-soluble organic dye having at least one boric acid group on the aryl radical, (b) a pH for maintaining the formulation at a pH of about 6-9. An inkjet ink for an inkjet printer, comprising an adjusting agent and (c) residual water.