JPH07292299A - Recording fluid and its production - Google Patents

Abstract

PURPOSE:To obtain a water-base recording fluid which is used for ink jet recording and gives a water-resistant recorded material by dissolving an oil-soluble dye in an organic solvent to form an aqueous emulsion and then distilling off the organic solvent. CONSTITUTION:A solution of an oil-soluble dye in an organic solvent is mixed with water in the presence of a dispersion stabilizer to form an emulsion, and the solvent is then distilled off. The solvent is selected in respect of the capability of dissolving the dye; however, methyl ethyl ketone, acetone, methanol, toluene, etc., are suitable in particular. It is desirable to incorporate the dispersion stabilizer into the solution of the dye beforehand preferably at a weight ratio of the dye to the dispersion stabilizer of (5:1) to (1:5). As the dispersion stabilizer, e.g. a surfactant is used; however, the use of at least two kinds is desirable to improve the water resistance of a printed material. The distillation of the organic solvent from the emulsion is performed under a reduced pressure and, if necessary, by heating to thereby effect the phase inversion of the emulsion. Unlike the one based on a water-soluble dye, this recording fluid gives a recorded material free from blotting of the ink when the material becomes wet with water.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a recording liquid having excellent water resistance. More specifically, the present invention relates to a recording liquid having excellent water resistance while being water-based, and a method for producing the recording liquid.

[0002]

2. Description of the Related Art Conventionally, as an ink jet recording liquid, a water-soluble dye such as an acid dye, a direct dye or a basic dye dissolved in a glycol solvent and water is often used. However, as the water-soluble dye, those having high solubility in water are generally used in order to obtain stability of the recording liquid. Therefore, the ink jet recorded matter generally has poor water resistance, and there is a problem that spillage of water easily causes bleeding of the dye in the recorded portion.

In order to improve such poor water resistance,
Attempts have been made to change the structure of the dye or to prepare a recording liquid with strong basicity. In addition, the water resistance is also improved by making good use of the reaction between the recording paper and the recording liquid. Although these methods have a remarkable effect on a certain kind of recording paper, various recording papers are used in the recording by the ink jet method, and therefore the recording liquid containing a water-soluble dye has sufficient water resistance. Is often not obtained.

Recording liquids having good water resistance include those in which an oil-soluble dye is dispersed or dissolved in a high boiling point solvent and those in which an oil-soluble dye is dissolved in a volatile solvent. May be environmentally disliked by the emission of
The need for solvent recovery may be a problem when recording a large amount of data or depending on the installation location of the device. Further, JP-A-62-207375 discloses a method of obtaining an aqueous ink by dissolving an oil-soluble dye in an organic solvent and then dispersing it in water. According to this method, a recording liquid which is water-soluble and has good water resistance can be obtained. However, it cannot be said that the solubility of the oil-soluble dye in an organic solvent is necessarily sufficient, and the dye concentration becomes high when dispersed in water. It was difficult to do. In addition, since the recording liquid contains a large amount of organic solvent, there was a problem of odor and discharge of the solvent.

Therefore, in order to improve the water resistance of the recorded matter, a recording solution in which a pigment is dispersed in an aqueous medium has been developed. However, in order to obtain the dispersion stability of the pigment, it is necessary to sufficiently miniaturize the pigment, and in this production, a technique capable of finely dispersing the pigment by an easy operation is required. A disperser having a large dispersive energy is also required for dispersion for making the pigment fine.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide an aqueous recording liquid capable of obtaining a recorded product having good water resistance on any paper and a method for easily producing the same.

[0007]

That is, according to the present invention, a solution obtained by dissolving an oil-soluble dye in an organic solvent is mixed with water in the presence of a dispersion stabilizer, and then the organic solvent is distilled off. Provided is a method for producing a recording liquid, and a recording liquid produced by the method.

The oil-soluble dye of the present invention is a dye which is soluble in an organic solvent such as alcohol, ketone, ether, ester, aromatic or aliphatic and is not soluble in water. Examples of oil-soluble dyes include “CI Solvent Yellow 2,6,1
4,15,19,21,33,56,61,80,149 "," CI Solvent Orange 1,2,6,14,37,40,44,45 "," CI Solvent Red 1,3,8,23, " 24,25,27,30,49,81,82,83,84,100,109,121,
132,218 ", CI Disperse Red 9", "CI Solvent Blue 2,11,12,25,35,36,55,73", "CI Solvent Black 3,5,7,22,23,27", "CI Solvent violet 8, 13, 14, 21, 27 "and the like can be exemplified.

The organic solvent that dissolves the oil-soluble dye can be appropriately selected based on the solubility of the oil-soluble dye.
Methyl ethyl ketone, acetone, methanol, ethanol, isopropyl alcohol, toluene and the like are suitable for producing the recording liquid of the present invention. These organic solvents have good solubility of the dye and do not adversely affect the properties of the recording liquid even if they partially remain in the recording liquid.

A solution prepared by dissolving an oil-soluble dye in an organic solvent is mixed with water in the presence of a dispersion stabilizer. The dispersion stabilizer is preferably contained in the solution of the oil-soluble dye in advance. The weight ratio of the oil-soluble dye / dispersion stabilizer is 9/1 to 1/9, more preferably 5/1 to 1 in order to obtain sufficient dispersion stability of the oil-soluble dye after distilling the organic solvent. /
Set to 5. If the amount of the dispersion stabilizer is less than this amount, the effect on the dispersion stability of the oil-soluble dye cannot be sufficiently obtained. On the other hand, if the amount is larger than this, the viscosity becomes high, which is not preferable in terms of the drying property as a recording liquid and the printing quality. As the dispersion stabilizer, a surfactant, a water-soluble or water-dispersible low-molecular compound, an oligomer, a high-molecular compound or the like is used.

As the surfactant, anionic, nonionic, cationic or amphoteric surfactant can be used. Examples of the anionic activator include fatty acid salt, alkyl sulfate ester salt, alkyl aryl sulfonate, alkyl naphthalene sulfonate, dialkyl sulfonate, dialkyl sulfosuccinate, alkyl diaryl ether disulfonate, alkyl phosphate, poly Examples thereof include oxyethylene alkyl ether sulfate, polyoxyethylene alkylaryl ether sulfate, naphthalene sulfonic acid formalin condensate, polyoxyethylene alkyl phosphate ester salt, glycerol borate fatty acid ester, and polyoxyethylene glycerol fatty acid ester.

As the nonionic activator, polyoxyethylene alkyl ether, polyoxyethylene alkylaryl ether, polyoxyethylene oxypropylene block copolymer, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester, Examples thereof include glycerin fatty acid ester, polyoxyethylene fatty acid ester, polyoxyethylene alkylamine, fluorine-based and silicon-based nonionic activators. Examples of the cationic activator include alkylamine salts, quaternary ammonium salts, alkylpyridinium salts, alkylimidazolium salts and the like. Examples of the zwitterionic activator include alkylbetaine, alkylamine oxide, phosphadylcholine and the like.

Further, water-soluble or water-dispersible low molecular weight compounds, oligomers and high molecular weight compounds are dissolved in an organic solvent, and after distilling the organic solvent, a carboxyl group, a sulfonic acid group and a phosphoric acid group which are also soluble in water. , Having a hydrophilic functional group such as a hydroxyl group and a polyoxyalkylene group. These are polyolefins, acrylics, epoxies with anionic, nonionic or cationic hydrophilic groups,
It is a compound of urethane type, polyester type, silicon type, fluorine type and the like.

As the compound having an anionic hydrophilic group, maleinized polyolefin resin, α-olefin-
Examples include maleic anhydride resins, styrene-maleic anhydride resins, acrylic resins having acid groups such as carboxyl groups, sulfonic acid groups, phosphoric acid groups, silicone resins, fluorine resins, etc., neutralized with alkaline compounds such as amines. it can. Among them, the amine neutralized product of the compound having a carboxyl group acts as an excellent dispersion stabilizer in water, and after printing, the amine volatilizes to decrease the hydrophilicity and improve the water resistance of the recorded matter, which is preferable. The acid value of the compound having a carboxyl group is preferably 10 to 300. Such compounds include lauric acid, myristic acid, palmitic acid,
Examples include stearic acid, oleic acid, maleated polyolefin resin, styrene acrylic resin, styrene acrylic acid resin, and the like.

As the compound having a nonionic hydrophilic group, polyethylene glycol, polyvinyl alcohol,
Examples include cellulose derivatives and acrylic resins having a polyoxyalkylene group. Examples of the compound having a cationic hydrophilic group include those obtained by neutralizing an acrylic resin having an amino group with an acid, chitosan, polyethyleneimine, polyacrylic acid hydrazide and the like.

The above dispersion stabilizer can be used in an optional ratio so as to improve the dispersion stability of the oil-soluble dye in the recording liquid and the water resistance of the recorded matter. The dispersion stabilizer which is preferably used in combination is two or more kinds of surfactants,
When an anionic surfactant and a nonionic surfactant are used in combination, and when a nonionic surfactant having a different HLB is used in combination, a recording liquid with particularly good dispersibility is obtained. Also, when a resin having an anionic hydrophilic group is used in combination with a nonionic surfactant, a recording liquid having good dispersibility can be obtained.

When a highly hydrophobic nonionic activator having an HLB of 10 or less and a highly hydrophilic nonionic activator having an HLB of more than 10 are combined, the hydrophilic component remaining on the recorded material is reduced as much as possible. As a result, the oil-soluble dye can be stably dispersed in water, which is also effective for further improving the water resistance of the recorded matter. Specifically, especially HLB is 9.5 to 10.0
It is preferable to use those having a HLB of 12.5 to 13.5 in combination.

When a solution prepared by dissolving an oil-soluble dye in an organic solvent is mixed with water, it is also preferable to add an antifoaming agent to prevent foaming. A silicon emulsion type defoaming agent is suitable as the defoaming agent. Further, a neutralizing agent may be added to adjust the pH of the recording liquid or to obtain solubility of a compound having a carboxyl group as a dispersion stabilizer. As the neutralizing agent, amine and inorganic alkali are used. Examples of the amine include triethanolamine, diethanolamine, dimethylethanolamine and the like. Examples of the inorganic alkaline compound include ammonia and sodium hydroxide. The neutralizing agent may be added in a slightly excessive amount up to the alkali side. The preferred pH of the recording liquid is 7.5-10.5.

The recording liquid of the present invention using water as a medium is prepared by preparing a W / O emulsion by mixing and stirring a solution prepared by dissolving an oil-soluble dye in an organic solvent with water in the presence of a dispersion stabilizer. It is manufactured by distilling an organic solvent by a method such as drying under reduced pressure and phase conversion. Mixing and stirring can be performed by a high-speed dispersing machine, an emulsifying machine, etc., in addition to the usual stirring using a stirrer using blades. The organic solvent is distilled off by depressurizing with an evaporator or the like and heating if necessary. Before or after distilling the organic solvent, water or a high-boiling hydrophilic organic solvent can be added to adjust the viscosity and concentration of the recording liquid. The end point of the distillation of the organic solvent can be observed by the boiling point of the distillate and the boiling point of the distillate.

The recording liquid produced according to the present invention is suitable for use as an inkjet recording liquid because it is water-based but has extremely good water resistance, and is suitable for use in the preparation of documents in offices, addressing of postal matter, cardboard, etc. It can be used in the fields of marking, numbering, bar code, etc.

[0021]

EXAMPLES The present invention will be described in more detail based on the following examples. In the examples, parts and% represent parts by weight and% by weight, respectively. [Example 1] The following raw materials were mixed to prepare an organic solvent solution of an oil-soluble dye. Methyl ethyl ketone (hereinafter referred to as MEK) 175 parts Nonionic surfactant (HLB = 9.7) 1.25 parts Nonionic surfactant (HLB = 13.3) 5.00 parts Oil-soluble dye solution 135 parts ("Zeneca" PRO JET BLACK MEK Liquid ”, dye concentration 10%) While stirring the organic solvent solution of oil-soluble dye, the following raw materials were added dropwise. Dimethylethanolamine 1.30 parts Silicone emulsion type water-based antifoaming agent 1.25 parts (Kao's "Anti-Home E20") Purified water 475 parts After dropping, MEK is distilled off with an evaporator to perform phase conversion, An aqueous recording liquid was obtained. This recording liquid was filtered through a 0.8 μ filter to remove coarse particles, and an inkjet ink was prepared. When this ink was put in a cartridge of "thinkjet" manufactured by Hewlett-Packard Co., and recording was performed, a good recorded matter was obtained. When water was dripped on the recording surface and ink bleeding was examined, there was no ink bleeding or runoff, and it had sufficient water resistance.

[Example 2] 1.05 parts of a nonionic surfactant (HLB = 9.9) and a nonionic surfactant (H
LB = 13.1) 4.50 parts, dimethyl ethanolamine 1.30
An aqueous recording liquid was obtained in the same manner as in Example 1 except that the part was removed. This recording liquid was filtered through a 0.45μ filter to remove coarse particles, and an inkjet ink was prepared. Using this ink, recording was carried out in the same manner as in Example 1, and good printed matter was obtained. When water was dripped on the recording surface and ink bleeding was examined, there was no ink bleeding or runoff, and it had sufficient water resistance.

[Example 3] 1.05 parts of a nonionic surfactant (HLB = 9.7) and a nonionic surfactant (H
LB = 13.5) 4.50 parts, 135 parts of the oil-soluble dye solution was replaced with 145 parts, and 1.30 parts of dimethylethanolamine was replaced with 1.25 parts to obtain an aqueous recording liquid in the same manner as in Example 1.
This recording liquid was filtered with a 1.0 μ filter to remove coarse particles, and an inkjet ink was prepared. Using this ink, recording was carried out in the same manner as in Example 1, and good printed matter was obtained. When water was dripped on the recording surface and ink bleeding was examined, there was no ink bleeding or runoff, and it had sufficient water resistance.

[Example 4] 1.0 part of a nonionic surfactant (HLB = 9.8) and a nonionic surfactant (H
LB = 12.8) An organic solvent solution of an oil-soluble dye was prepared in the same manner as in Example 1 except that 4.5 parts were used. Then, while stirring the organic solvent solution of the oil-soluble dye, a solution prepared by dissolving 1.25 parts of silicon emulsion type water-based defoaming agent "Antihome E20" in 475 parts of purified water was sequentially added dropwise. After dropping, the organic solvent was distilled off with an evaporator to convert the phase,
An aqueous recording liquid was obtained. This recording liquid was filtered with a 1.0 μ filter to remove coarse particles, and an inkjet ink was prepared. Using this ink, recording was carried out in the same manner as in Example 1, and good printed matter was obtained. When water was dripped on the recording surface and ink bleeding was examined, there was no ink bleeding or runoff, and it had sufficient water resistance.

[Example 5] The surfactant was 1.0 part of a nonionic surfactant (HLB = 9.5) and a nonionic surfactant (H).
LB = 13.3) An organic solvent solution of an oil-soluble dye was prepared in the same manner as in Example 1 except that 5 parts of butyl cellosolve was added instead of 4.5 parts. Then, an inkjet ink was prepared in the same manner as in Example 4. Using this ink, recording was carried out in the same manner as in Example 1, and good printed matter was obtained. When water was dripped on the recording surface and ink bleeding was examined, there was no ink bleeding or runoff, and it had sufficient water resistance.

[Example 6] 1.0 part of a nonionic surfactant (HLB = 9.8) and a nonionic surfactant (H
LB = 13.0) An organic solvent solution of an oil-soluble dye was prepared in the same manner as in Example 1 except that 5 parts of isopropyl alcohol was added instead of 4.5 parts. Then, an inkjet ink was prepared in the same manner as in Example 4. Using this ink, recording was carried out in the same manner as in Example 1, and good printed matter was obtained. When water was dripped on the recording surface and ink bleeding was examined, there was no ink bleeding or runoff, and it had sufficient water resistance.

Examples 7 to 12 Ink jet inks were prepared in the same manner as in Example 1 except that the oil-soluble dye solution was replaced with the following dye solution. Using this ink, recording was carried out in the same manner as in Example 1, and good printed matter was obtained. When water was dripped on the recording surface and ink bleeding was examined, there was no ink bleeding or runoff, and it had sufficient water resistance. Example 7: "Oil Black BY" manufactured by Orient Chemical Co., Ltd. 1
3.5 parts of MEK dissolved in 300 parts. Example 8: "Oil Blue BOS" manufactured by Orient Chemical Co., Ltd. 1
3.5 parts of MEK dissolved in 300 parts. Example 9: 13.5 parts of "Oil Red" manufactured by Orient Chemical Co., Ltd. dissolved in 300 parts of MEK. Example 10: A solution prepared by dissolving 14.5 parts of "FAT BLACK HB-01" manufactured by Hoechst Co. in 300 parts of MEK. Example 11: "PRO JET BLACK ALC POWDER" manufactured by Zeneca 1
4.5 parts dissolved in 300 parts ethanol. Example 12: "PRO JET BLACK ETOH Liquid" manufactured by Zeneca
(Dye concentration 10%)

An aqueous sodium hydroxide solution was added to the ink jet inks obtained in Examples 1 to 12 to adjust the conductivity.
Adjusted to 0.8 mS or more. This ink can perform stable printing from the 35μ nozzle of a continuous jet type (suite type) inkjet printer, and the recorded characters do not run or bleed even if water is dripped, and good water resistance. showed that. Further, the ink jet inks obtained in Examples 1 to 12 can perform stable printing from a 40 μ nozzle of an on-demand type ink jet printer, and the recorded characters run out or bleed even if water is dripped. And showed good water resistance.

Example 13 The following raw materials were mixed to prepare a solution of an oil-soluble dye in an organic solvent. Anionic surfactant (Kao's "Perex OTP") 10 parts Oil-soluble dye solution 100 parts (Zeneca's "PRO JET BLACK ETOH Liquid", dye concentration 10%) Butyl carbitol 10 parts Isopropyl alcohol 100 parts Oil-soluble The following raw materials were sequentially added dropwise while stirring the organic solvent solution of the dye. Silicone emulsion type water-based defoaming agent "Antihome E20" 3 parts Purified water 170 parts After dropping, ethanol and isopropyl alcohol were distilled off with an evaporator to perform phase conversion to obtain an aqueous recording liquid. Purified water (150 parts) was added to this recording liquid to adjust the concentration, and then filtered through a 1.0 μ filter to remove coarse particles to prepare an inkjet ink. Using this ink, recording was carried out in the same manner as in Example 1, and good printed matter was obtained. When water was dripped on the recording surface and ink bleeding was examined, there was no ink bleeding or runoff, and it had sufficient water resistance.

Example 14 The following raw materials were mixed to prepare a solution of an oil-soluble dye in an organic solvent. MEK 175 parts Anionic surfactant (Kao's "Perex OTP") 10 parts Nonionic surfactant (HLB = 13.3) 4.50 parts Oil-soluble dye solution 145 parts (Zeneca "PRO JET BLACK MEK Liquid , Dye concentration 10%) Butyl carbitol 10 parts While stirring a solution of an oil-soluble dye in an organic solvent, the following raw materials were sequentially added dropwise. Silicone emulsion type water-based defoaming agent "Anti-Home E20" 3 parts Purified water 170 parts After dropping, MEK was distilled off with an evaporator to change the phase to obtain an aqueous recording liquid. Purify water with this recording liquid 1
After adjusting the concentration by adding 80 parts, filtration was performed with a 1.0 μ filter to remove coarse particles to prepare an inkjet ink. Using this ink, recording was carried out in the same manner as in Example 1, and good printed matter was obtained. When water was dripped on the recording surface and ink bleeding was examined, there was no ink bleeding or runoff, and it had sufficient water resistance.

Example 15 The nonionic surfactant was replaced with 6.50 parts of styrene acrylic resin ("Johncryl 68" manufactured by Johnson Polymer Co., acid number 195) and 1.8 parts of dimethylethanolamine, and 10 parts of butyl carbitol was used. An aqueous recording liquid was obtained in the same manner as in Example 16 except that 8 parts were used. After 170 parts of purified water was added to this recording liquid to adjust the concentration, it was filtered with a 1.0 μ filter to remove coarse particles and prepare an inkjet ink. Using this ink, recording was carried out in the same manner as in Example 1, and good printed matter was obtained. When water was dripped on the recording surface and ink bleeding was examined, there was no ink bleeding or runoff, and it had sufficient water resistance.

Example 16 The following raw materials were mixed to prepare a solution of an oil-soluble dye in an organic solvent. MEK 100 parts Anionic surfactant (Kao's "Perex OTP") 10 parts Styrene acrylic resin 10 parts (Gifu shellac "GSM-505", acid value 176) Ammonia water 2 parts Oil-soluble dye solution 100 parts (“PRO JET BLACK MEK Liquid” manufactured by Zeneca Co., dye concentration 10%) While stirring an organic solvent solution of an oil-soluble dye, the following raw materials were sequentially added dropwise. Silicone emulsion type water-based defoaming agent "Antihome E20" 1 part Purified water 180 parts After dropping, MEK was distilled off with an evaporator to perform phase conversion to obtain an aqueous recording liquid. Add 20 parts of purified water to this recording liquid.
After adjusting the concentration by adding a part of the mixture, the mixture was filtered through a 1.0 μ filter to remove coarse particles to prepare an inkjet ink. Using this ink, recording was carried out in the same manner as in Example 1, and good printed matter was obtained. When water was dripped on the recording surface and ink bleeding was examined, there was no ink bleeding or runoff, and it had sufficient water resistance.

Example 17 The following raw materials were mixed to prepare a solution of an oil-soluble dye in an organic solvent. Cationic surfactant (Kaomin "Potamin 24P") 10 parts Oil soluble dye 100 parts (Zeneca "PRO JET BLACK ETOH Liquid", dye concentration 10%) Isopropyl alcohol 100 parts Organic solvent solution of oil soluble dye The following raw materials were sequentially added dropwise while stirring. Silicone emulsion type water-based defoamer "Antihome E20" 1 part Purified water 180 parts After dropping, ethanol and isopropyl alcohol were distilled off with an evaporator to change the phase to obtain an aqueous recording liquid. 20 parts of purified water was added to this recording liquid to adjust the concentration, and then filtered with a 1.0 μ filter to remove coarse particles to prepare an inkjet ink. Using this ink, recording was carried out in the same manner as in Example 1, and good printed matter was obtained. When water was dripped on the recording surface and ink bleeding was examined, there was no ink bleeding or runoff, and it had sufficient water resistance.

Comparative Example 1 The oil-soluble dye solution of Example 1 and water were stirred at high speed to prepare an emulsion ink. The ink had a strong solvent odor during recording.

Table 1 shows the results of evaluation of the reflection density and water resistance of the recorded materials obtained in the examples and comparative examples. The reflection density was measured with "RD-918" manufactured by Macbeth, and the water resistance was evaluated by the decrease in reflection density when the recorded matter was immersed in water for 24 hours (○: decrease in reflection density was less than 5%, × : Decrease in reflection density was 5% or more).

[0036]

[Table 1]

[0037]

According to the present invention, it is possible to obtain a recording liquid which gives a recorded product having good water resistance while using water as a medium. This greatly reduces the restrictions on the recording medium,
In the past, it is expected that the applications of aqueous recording liquids, which have often been deficient in water resistance due to the influence of the recording medium, will be expanded.

Claims (4)

[Claims] 1. A method for producing a recording liquid, characterized in that a solution obtained by dissolving an oil-soluble dye in an organic solvent is mixed with water in the presence of a dispersion stabilizer, and then the organic solvent is distilled off. . 2. A W / O emulsion is prepared by mixing a solution obtained by dissolving an oil-soluble dye in an organic solvent with water in the presence of a dispersion stabilizer, and then distilling the organic solvent to carry out phase conversion. A method for producing a recording liquid, which comprises: 3. A recording liquid produced by the method according to claim 1. 4. The recording liquid according to claim 3, which is used for inkjet.