JPH10310732A - Ink-jet recording ink - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject ink that has satisfactory nozzle jetting stability on printing and ink drying behavior by admixing a specific water-soluble polyether-modified silicone compound to an ink for ink-jet recording. SOLUTION: This ink mainly comprises (A) a pigment, (B) a water-based resin, (C) a basic compound, (D) a water-soluble polyether-modified silicone, preferably having the structure of the formula (X, Y are each polyalkylene oxide chain containing at least one of ethylene oxide unit; R<1> and R<2> are each alkylene; m is an integer of 1 or more), (E) an aqueous medium. The amount of the component D is preferably 0.01-2.0 wt.% per 100 wt.% of this ink. Further, the component A is 1-30 wt.%, the component B is preferably 0.1-20 wt.% based on 100 wt.% of the ink thereby providing the objective ink that can simultaneously satisfy conflicting properties.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording method in which ink is ejected from an ejection port of a recording head and is ejected as droplets to perform recording. The present invention relates to an ink jet recording ink which is excellent in printing quality such as sharpness and sharpness, and nozzle ejection stability.

[0002]

2. Description of the Related Art An image is formed by an ink jet method in which ink is ejected by using an electrostatic suction method, a pneumatic feeding method, a method utilizing pressure during heating and foaming, a method utilizing electric deformation of a piezoelectric element, or the like. Conventionally, the ink used at the time of forming an image on a recording sheet has an irregular ink flow along the fibers of the recording sheet and an irregular ink permeation between the fibers (hereinafter referred to as bleeding). ), Fast drying when an image is formed on recording paper, no clogging of nozzles during long-term storage, that is, good nozzle ejection stability, and good water resistance of the image. It is required to satisfy certain properties such as certain things, but these are mutually contradictory.

[0003] In particular, in recent years, there has been a demand for an ink which has a fast drying property, has no bleeding, and has a good nozzle discharge stability, and various techniques have been proposed for the purpose of achieving both of these contradictory characteristics. .

[0004] For example, Japanese Patent Application Laid-Open No. 55-16042,
JP-A-55-29546 discloses that the use of a dye, a specific high-boiling water-soluble solvent and water as main components for improving the ejection stability of the nozzle, and the use of various surfactants for improving the quick drying property. Has been proposed. However, in this method, since the ink penetrates too much into the paper, bleeding and sharpening of the outline are not performed.
However, there was a problem that the print quality such as image quality and sharpness was deteriorated, which was not satisfactory.

Further, when a water-soluble dye is used, a dye having high solubility in water is often used due to the stability of the ink, and the water resistance of an ink-jet recorded matter is lowered, and the recorded matter is exposed to water. There is a problem in water resistance and weather resistance, such as easy bleeding, and in this regard, it is better to use a pigment as a coloring material.

However, pigment-based inks for ink-jet recording are compared with dye-based inks for ink-jet recording due to the low dispersibility of the pigment and the aqueous resin added to enhance the dispersibility of the pigment in aqueous media. Therefore, problems such as slow drying property and poor nozzle discharge stability occur. Therefore, it is difficult to simultaneously satisfy conflicting properties such as print quality such as bleeding, nozzle ejection stability during printing, drying properties, water resistance of recorded matter, and weather resistance. This has not been achieved with the prior art.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has excellent water resistance and weather resistance of a recorded matter which is an advantage of a pigment-based ink for inkjet recording. To provide an ink jet recording ink which is excellent in print quality such as bleeding, contour sharpness, sharpness, etc., which is equal to or higher than that of dyes, nozzle ejection stability during printing, drying property, etc. It is intended for.

[0008]

Means for Solving the Problems As a result of repeated studies to solve the above-mentioned problems, the present inventors have found that a water-soluble polyether having a polyalkylene oxide structure introduced at the terminal of dimethylpolysiloxane is added to an ink jet recording ink. -It has been found that these problems can be solved by including a tellurium-modified silicon-based compound, and the present invention has been completed.

That is, the present invention has the following constitutions: (1) In an ink jet recording ink mainly composed of a pigment, an aqueous resin, a basic compound, a silicon compound and an aqueous medium, a silicon compound An ink jet recording ink comprising a water-soluble polyether-modified silicon-based compound having a polyalkylene oxide structure introduced into a terminal of dimethylpolysiloxane. (2) The inkjet according to (1), which contains 0.01 to 2.0% by weight of a water-soluble polyether-modified silicon-based compound having a polyalkylene oxide structure introduced into a terminal of dimethylpolysiloxane. Recording ink. (3) The ink for inkjet recording according to (1) or (2), wherein the polyalkylene oxide structure at the terminal of the polyether-modified silicon-based compound contains at least one ethylene oxide group. (4) The inkjet according to any one of (1) to (3), wherein the polyether-modified silicone compound is represented by the following general formula (1) and / or general formula (2). Recording ink. (Wherein X and Y may be the same or different,
A polyalkylene oxide chain containing at least one ethylene oxide group, R ₁ and R ₂ may be the same or different alkylene groups, and m represents an integer of 1 or more. ) (In the formula, Z is a polyalkylene oxide chain containing at least one ethylene oxide group, and n is an integer of 1 or more.)

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. The silicon compound used in the ink jet recording ink of the present invention is a water-soluble polyether-modified silicon compound having a polyalkylene oxide structure introduced into the terminal of dimethylpolysiloxane.

In the present invention, the polyalkylene oxide structure is a linear or branched polyalkyl ether having an alkylene oxide group as a structural unit.

The polyalkylene oxide structure in the water-soluble polyether-modified silicon compound used in the present invention preferably has an alkylene oxide group having 2 to 4 carbon atoms as a structural unit. The alkylene oxide group as a structural unit may be one type or two or more types.
In the present invention, it is more preferable that the polyalkylene oxide structure contains at least one ethylene oxide group, and the others are arbitrarily composed of one or more alkylene oxide groups having 3 or 4 carbon atoms. Particularly preferably, the polyalkylene oxide structure is a polyethylene oxide structure. When the polyalkylene oxide structure is a polyethylene oxide structure, the solubility of the polyether-modified silicon-based compound in water is improved.

When two or more alkylene oxide groups are used as structural units in the alkylene oxide structure, each structural unit may be randomly polymerized or block polymerized.

The number of the alkylene oxide groups in the alkylene oxide structure and the molecular weight of the water-soluble polyether-modified silicon compound used in the present invention may be appropriately set according to the required properties of the ink for inkjet recording. .

The water-soluble polyether-modified silicon-based compound used in the present invention is not particularly limited as long as it satisfies the above-mentioned conditions, and one kind may be used alone or two or more kinds may be used. You may use together.

Preferred examples of the water-soluble polyether-modified silicon compound used in the present invention include those represented by the following general formulas (1) and / or (2). (Wherein X and Y may be the same or different,
A polyalkylene oxide chain containing at least one ethylene oxide group, R ₁ and R ₂ may be the same or different alkylene groups, and m represents an integer of 1 or more. ) (In the formula, Z is a polyalkylene oxide chain containing at least one ethylene oxide group, and n is an integer of 1 or more.)

The water-soluble polyether-modified silicon-based compound used in the present invention can be obtained as a commercial product. For example, as the compound represented by the general formula (1), trade names: SF8427, BY16-004 ( As those represented by the general formula (2) such as Toray Dow Corning Silicone Co., Ltd., trade names: SILWET L-72
0 (manufactured by Nippon Unicar Co., Ltd.) and the like, but are not limited thereto.

In the present invention, the amount of the water-soluble polyether-modified silicon compound may be appropriately set according to the characteristics of the intended ink for ink jet recording.
Preferably, 100% by weight of ink for inkjet recording
To 0.01 to 2.0% by weight,
More preferably, the content is 0.1 to 1.0% by weight. If the compounding amount is small, the drying property is reduced, while if it is large, the printing suitability such as bleeding is reduced.

The ink for ink-jet recording of the present invention comprises:
Surface tension (25 ° C.) is preferably 20 to 35 dyne /
cm ² , more preferably 23 to 33
dyne / cm ² is good. Surface tension is 35d
When it is larger than yne / cm ² , the drying property is reduced. On the other hand, when it is smaller than ²⁰ dyne / cm ² , printability such as bleeding is reduced.

The pigment used in the ink jet recording ink of the present invention is not particularly limited, and known inorganic and organic pigments that can be dispersed in an aqueous medium can be used. Is preferable. For example, as inorganic pigments, titanium oxide, red iron oxide, antimony red, cadmium red, cadmium yellow, cobalt blue, navy blue, ultramarine, carbon black, graphite, etc., as organic pigments, soluble azo pigments, insoluble azo pigments Azo pigments, condensed azo pigments, copper phthalocyanine pigments, condensed polycyclic pigments, and the like.

The amount of the pigment is preferably 1 to 3 with respect to 100% by weight of the ink for ink jet recording.
0% by weight, more preferably 2 to 10%.
% By weight is good. When the amount is less than this range, the color density is reduced. On the other hand, when the amount is more than this range, it becomes difficult to use the ink in terms of viscosity and fluidity.

The aqueous medium used in the ink jet recording ink of the present invention is not particularly limited, and water or a mixture of water and a water-miscible solvent, which is conventionally generally used in the art, is used. be able to.

The water-miscible solvent is not particularly limited as long as it does not hinder the operation of the present invention and does not damage the printing apparatus. For example, lower alcohols, polyhydric alcohols And their derivatives, nitrogen-containing cyclic compounds, and the like.

Specifically, lower alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol and isopropyl alcohol, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, glycerin, polyglycol Polyhydric alcohols such as glycerin, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol acetate, diethylene glycol monomethyl ether , Polypropylene alcohol derivatives such as dipropylene glycol monomethyl ether, nitrogen-containing cyclic compounds such as N-methyl-2-pyrrolidone and N-ethyl-2-pyrrolidone, and ethylene oxide addition of polyglycerin Etc. can be used. Among them,
From the viewpoint of ejection stability, an ethylene oxide adduct of polyglycerin is preferred. In particular, those obtained by adding 5-90 mol of ethylene oxide to 1 mol of polyglycerin are preferable. The water-miscible solvents may be used alone or in combination of two or more.

The mixing ratio of water and the water-miscible solvent may be set as appropriate in accordance with the desired characteristics of the ink for inkjet recording.

The aqueous resin used in the ink jet recording ink of the present invention is not particularly limited, and those generally used in the art can be used. Specifically, the weight average molecular weight is 5,000 to 30,0
Patent Application No. 7 related to the applicant's application in the range of 00
-255233, water-based resin, alkyl acrylate- (meth) acrylic acid-based copolymer, styrene-acrylic acid copolymer, styrene-acrylic acid-
Acrylic acid alkyl ester copolymer, styrene-maleic acid copolymer, styrene-maleic acid-alkyl acrylate copolymer, styrene-methacrylic acid copolymer, styrene-methacrylic acid-alkyl acrylate copolymer, Styrene-maleic acid half ester copolymer and the like can be mentioned. These may be used alone or in combination of two or more.

The aqueous resin is preferably used in an amount of 0.1 to 20% by weight, more preferably 0.2 to 10% by weight, based on 100% by weight of the ink for ink jet recording.
It is good to mix in the range of weight%.

The basic compound used in the ink for ink-jet recording of the present invention is not particularly limited as long as it can dissolve the above-mentioned aqueous resin in the above-mentioned aqueous medium by its compounding. Basic compounds that have been used to dissolve in aqueous media can be used.

Examples include alkylamines such as butylamine and triethylamine, alkanolamines such as monoethanolamine, diethanolamine, and triethanolamine, morpholine, aqueous ammonia, sodium hydroxide, and the like. Among them, clogging of the discharge orifice. It is desirable to use a fast-volatile basic compound and a slow-volatile basic compound in combination from the viewpoint of reducing the concentration. These may be used alone or in combination of two or more.

The ink jet recording ink of the present invention may further contain a surfactant, a pigment dispersant,
Various additives such as a viscosity modifier, an antifoaming agent, a fungicide, a preservative, and a rust inhibitor may be added.

The ink for ink-jet recording of the present invention can be produced by a method generally used in the art. For example, a pigment, an aqueous resin, a basic compound, an aqueous medium, if necessary, a surfactant, a pigment dispersion Mixing agent, viscosity modifier, antifoaming agent, etc., various dispersion / stirring machines, for example,
Bead mill, ball mill, sand mill, attritor,
Dispersed using a roll mill, agitator, Henschel mixer, colloid mill, ultrasonic homogenizer, ultra-high pressure homogenizer, par mill, etc., and further the remaining material, the polyether-modified silicon-based compound And the like are added and mixed. The polyether-modified silicon-based compound may be mixed before being dispersed.

In the present invention, as a method for obtaining a pigment dispersion having a desired particle size distribution as an ink for ink jet recording, the size of the pulverized media of the disperser is reduced, the filling rate of the pulverized media is increased, and the processing time is reduced. Means such as lengthening, slowing the discharge speed, and classifying with a filter or a centrifugal separator after pulverization can be used alone or in combination. Hereinafter, the present invention will be described more specifically with reference to Test Examples and Examples, but the present invention is not limited thereto.

Test Examples With respect to the ink jet recording inks of Examples 1 to 7 and Comparative Examples 1 to 3, the surface tension, drying property, bleeding, and print density were evaluated by the following methods.

(1) Test method Test example 1 Surface tension The surface tension at a temperature of 25 ° C. was measured using a surface tensiometer (HLV-
ST type, manufactured by Kyowa Interface Science Co., Ltd.).

Test Example 2 Dryness On-demand for applying the thermal energy to the recording liquid in the recording head to generate droplets by applying the ink jet recording inks of Examples 1 to 7 and Comparative Examples 1 to 3 to perform recording. PPC paper (manufactured by KOKUYO Co., Ltd., neutral paper; hereinafter, referred to as paper A), PPC paper (Matsushita Electric Industrial Co., Ltd., acid paper, hereinafter paper B) ) Was printed, and the time after printing was measured until the ink did not adhere to the finger by touch.

Test Example 3 Degree of bleeding Printing was performed in the same manner as in the drying property of Test Example 2, and bleeding was visually observed and evaluated based on the following criteria. A: Bleeding is not observed with the naked eye B: Bleeding is seen but characters can be recognized C: Bleeding occurs and characters cannot be recognized

Test Example 4 Print Density Printing was performed in the same manner as in the dryness of Test Example 2, and the optical density was measured for the solid portion of the print using an optical densitometer (RD-914, manufactured by Macbeth Co., Ltd.). Was measured.

(2) Test Results Table 1 shows the results of Test Examples 1 to 4.

[Table 1] From the above results, it can be seen that the ink jet recording inks of the examples are superior to the comparative examples in well-balanced dryness, bleeding, and print density characteristics.

[0039]

【Example】

[Adjustment of ink for inkjet recording] ion exchange water,
Ammonia water, carbon black (Prentex 35,
A compound obtained by adding 20 mol of ethylene oxide to 1 mol of polyglycerin (degree of polymerization: 4), diethylene glycol, acrylic copolymer resin [acid value 6
8, average molecular weight (Mw) 11,000, monomer composition;
Methacrylic acid / methyl methacrylate / stearyl methacrylate = 15.3 / 74.7 / 10] and a compound (pigment dispersant) obtained by adding 14 mol of ethylene oxide to p-hydroxyphenyl (see Table 2). ), Premixed for 1 hour, kneaded using a circulating bead mill, and further added ion-exchanged water according to the composition shown in Table 2 to obtain an ink jet recording ink.

[0040]

[Table 2]

Examples 1 to 7 and Comparative Examples 1 to 3 In addition to the above-mentioned ink for ink jet recording, SILWET L which is a polyether-modified silicon compound was used as an example.
-720 (manufactured by Nippon Unicar Co., Ltd.) or SF842
7 (manufactured by Dow Corning Toray Silicone Co., Ltd.) and sodium dioctylsulfosuccinate at a ratio shown in Table 1 as a comparative example to prepare an ink for inkjet recording, which was used as an example or a comparative example.

[0042]

The ink for ink jet recording according to the present invention, by blending a water-soluble polyether-modified silicon compound having a specific structure, has excellent water resistance and weather resistance of the recorded matter, which is an advantage of the pigment ink. It is excellent in print quality such as bleeding, sharpness of contour, sharpness, etc., and at the same time, in good balance with various characteristics such as nozzle discharge stability during printing and drying property. Excellent quality printing can also be performed on plain paper such as paper by inkjet recording.

Claims (4)

[Claims] 1. An ink jet recording ink mainly comprising a pigment, an aqueous resin, a basic compound, a silicon-based compound and an aqueous medium, wherein the silicon-based compound has a polyalkylene oxide structure introduced at the terminal of dimethylpolysiloxane. An ink for ink-jet recording, characterized by containing a polyether-modified silicon compound having a hydrophilic property. 2. The method according to claim 1, wherein a water-soluble polyether-modified silicon compound having a polyalkylene oxide structure introduced at the terminal of dimethylpolysiloxane is contained in an amount of 0.01 to 2.0% by weight. Ink for inkjet recording. 3. The ink for ink-jet recording according to claim 1, wherein the polyalkylene oxide structure at the terminal of the polyether-modified silicon compound contains at least one ethylene oxide group. 4. The ink jet recording apparatus according to claim 1, wherein the polyether-modified silicon compound is represented by the following general formula (1) and / or general formula (2). ink. (Wherein X and Y may be the same or different,
A polyalkylene oxide chain containing at least one ethylene oxide group, R ₁ and R ₂ may be the same or different alkylene groups, and m represents an integer of 1 or more. ) (In the formula, Z is a polyalkylene oxide chain containing at least one ethylene oxide group, and n is an integer of 1 or more.)