JPH0433309B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to an ink composition for an inkjet, and particularly relates to an ink composition for an inkjet that has excellent ink drying prevention ability and dispersion stability, and can also exhibit an excellent bleeding prevention effect. . (Prior Art) With the progress of color inkjet printing technology in recent years, attempts have been made to utilize it for textile printing on fabrics, as shown in, for example, Japanese Patent Application Laid-Open No. 1897-1897. When trying to use this on fabrics, there are many different types of fabrics to be dyed compared to when printing on paper, so inkjet inks use not only water-soluble dyes but also disperse dyes to accommodate these types of fabrics. , it is necessary to develop inks using water-insoluble dyes and pigments. When water-insoluble dyes are used as inkjet inks, various problems arise compared to water-soluble dye inks. For example, since water-soluble dye inks contain water-insoluble components, dye solidification is more likely to occur than in water-soluble dye inks, which causes clogging. Therefore, an extremely high ability to prevent drying is required. Therefore, if a water-soluble wetting agent is added to increase the drying prevention ability, some wetting agents may cause dye aggregation and inhibit dispersibility, or even if the dispersibility is good, the high boiling point may cause the dye to coagulate. Bleeding occurs when dyes and pigments are fixed, resulting in a disadvantage that bleeding cannot be prevented. According to the studies of the present inventors, the main properties that an inkjet ink composition using water-insoluble dyes and pigments should have are: (1) Extremely high anti-drying properties; (2) High dispersion stability. , (3) Does not impede bleeding prevention properties, etc. In the case of water-soluble dye inks, it is known to include humectants to minimize drying of the ink, especially at the nozzle. As wetting agents, alkyl glycols and alkylene groups containing 2 to 6 carbon atoms and in which the alkyl group contains 1 to 6 carbon atoms are disclosed in U.S. Pat. Nos. 3,705,043 and 3,846,141. Alkyl ethers of glycol, N-methyl-2-pyrrolidone, substituted pyrrolidone, etc. which also serve as dye solubilizers are known. In addition, JP-A-1986-
Polyalkylene glycols, amides, and nitrogen-containing heteroketones disclosed in No. 33145 are also known, and diethylene glycol and triethylene glycol are particularly preferred. If the wetting agents for water-soluble dye inks known so far are applied as they are to water-insoluble dyes and pigments, various problems arise. For example, ethylene glycol and diethylene glycol, which are conventionally considered to be the most effective in water-soluble dye inks, have no drying prevention ability at all, and can clog the nozzle if left in the nozzle for even a few minutes. A problem arises. It is extremely difficult to find a wetting agent for water-insoluble dyes and pigments, and no suitable wetting agent has yet been found. (Problems to be Solved by the Invention) An object of the present invention is to provide a water-insoluble dye and pigment ink composition for inkjet that has excellent drying prevention ability and can also provide dispersion stability and bleeding prevention properties. (Means for Solving the Problems) The present invention provides 10 to 50% by weight of C ₄ to _{C 6} to a water-based ink containing finely dispersed water-insoluble dyes and pigments having an average particle size of 1 μm or less. An ink composition for an inkjet, which contains a diol and has a viscosity of 2 to 10 cps at 35°C. The present invention will be explained in detail below. In the present invention, water-insoluble dyes and pigments include disperse dyes, oil-soluble dyes, pigments, and vat dyes. Among them, disperse dyes are particularly preferred. The concentration of the water-insoluble dye and pigment is usually 0.1 to 20% by weight, and the ink is prepared by finely dispersing the dye and pigment in a water-based medium together with a dispersant using a ball mill, colloid mill, sand grinder, or the like. The average particle size of water-insoluble dyes and pigments is
The particle size is 1μ or less, preferably 0.5μ or less, and the smaller the particle size, the better the dispersion stability of the dye and pigment. In the present invention, a compound represented by the following general formula is used as a dispersant. Q is a benzene nucleus or a naphthalene nucleus, R ₁ is a group containing a benzene nucleus or a naphthalene nucleus, m is 2 to 5, R ₂ is a non-aromatic group such as lower alkyl or halogen, n is 0 to 3, and Z is A divalent substituent, M represents ammonia, an amine, or a monovalent metal. The amount of dispersant used is 5% for the water-insoluble dye and pigment.
~100% by weight, preferably 10-50% by weight. The finely dispersed ink provides anti-drying ability to prevent nozzle clogging without impairing its dispersibility and anti-bleeding function. A feature of the present invention is that a dispersant represented by the general formula described above is used in the ink, and 10 to 50% by weight of C ₄ to _{C 6} diol is blended in the ink. According to studies conducted by the present inventors, most of the wetting agents that have been most commonly used in the past cannot be applied to water-insoluble dye and pigment inks for various reasons. For example, alkyl glycols with few carbon atoms, such as ethylene glycol, diethylene glycol, propylene glycol, and triethylene glycol, which are conventionally considered to be most effective in water-insoluble dye and pigment inks, and glycerin have no anti-drying ability at all, and even after a few minutes the nozzle If left unattended, the nozzle would become clogged. Alkyl ethers cause aggregation with dyes and pigments, resulting in significant dispersion destruction and thus losing their function as inks. Furthermore, since polyalkylene glycols have a high boiling point, they remain in large quantities in the fabric, which causes bleeding of the dye and pigment during color development and fixation, impairing the bleeding prevention function. In addition, solubilizing agents such as nitrogen-containing multiple ketones such as pyrrolidone and amides partially dissolve dyes and pigments, so the solvent in which dyes and pigments are dissolved may bleed on the fabric after inkjet. As expected, the anti-bleeding function was impaired. In addition, the re-ejectability of an inkjet after being left for a long time is not just due to dryness prevention or evaporation suppression, but there are other factors that ensure smooth and prompt ejection.Although the reason is not clear, it is highly hydrophobic. We have found that glycol, which has a high affinity with disperse dyes, is effective against this factor. The present inventors found that only _C4 - _C6 diols do not cause clogging even after leaving the nozzle for a long time, exhibit excellent anti-drying ability, have dispersion stability, and have relatively low Because it has a boiling point, it evaporates when the dye and pigment develop and fix color, and does not remain on the fabric. Therefore, it has been found that it does not impair the bleeding prevention function and has a high affinity with highly hydrophobic disperse dyes and the like. Examples of C ₄ to C ₆ diols include 1,3 butanediol, 1,4 butanediol, 2,3 butanediol, 1,5 pentanediol, 2,2 dimethyl 1,3 propanediol (neopentyl glycol), 1 , 6-hexylene diol, hexylene glycol, and other alkanediols.
Among these, 1,3-butanediol, 1,4-butanediol, and 2,2-dimethyl-1,3-propanediol are preferred. Additionally, these wetting agents have a boiling point of 250°C.
It is preferable that it is below. The amount of wetting agent used is 10 to 50% by weight based on the total ink. If it is less than 10%, there is almost no anti-drying ability, and 50%
% or more, the ink viscosity increases and it becomes difficult to eject the ink from the nozzle. In the present invention, the composition of the inkjet ink containing water-insoluble dyes and pigments includes, as ink components, the above-mentioned water-insoluble dyes and pigments, dispersibility, water, and wetting agents, as well as physical property modifiers (viscosity, PH, surface tension, electrical conductivity), It can contain preservatives, binders, etc. Furthermore, a chelating agent may be included to prevent aggregation of dyes and pigments in the ink. Further, for the purpose of preventing bleeding, the ink composition may contain a bleeding preventive agent, such as a water-dispersible polymer resin (for example, a water-dispersible polyester resin), which causes a small increase in viscosity and does not inhibit the dispersion stability of the ink. The physical properties of ink include viscosity and surface tension.
From the viewpoint of inkjet ejection properties, the viscosity should be 2 to 2.
It requires a surface tension of 10 cps (35° C.), and preferably a surface tension of 40 to 70 dyn/cm is used. The ink composition of the present invention shows its effect in ink sheet dyeing of fabrics, and examples of fabrics include knitted fabrics, woven fabrics, and nonwoven fabrics. There are no particular limitations on the material. The fabric may be pretreated with a cationic compound and/or a metal salt that exhibits an aggregation reaction with an anionic dispersant in order to prevent bleeding and obtain a high-quality pattern. The amount of these applied is usually about 0.2 to 10% by weight based on the fabric. When dyeing a pretreated fabric using an inkjet method, any inkjet method may be used, such as (1) a pressure vibration type, (2) a pressure pulse type, and (3) an electrostatic acceleration type. can give. Inkjet droplets usually have a diameter of 20 μm or more.
150μ, and the resolution is preferably about 2 to 16 lines/mm. If the droplets are spread about 1.5 to 4.0 times on the fabric, a high-quality pattern can be obtained. After inkjet dyeing, the dyed product can be obtained by developing and fixing the color using conventional methods under dry heat or moist heat, and washing as required. (Example) Hereinafter, the present invention will be specifically illustrated in Examples. Example 1 Using a satin fabric made of polyester fibers,
30 g of neofix RX-100 (polyamine type) (manufactured by NICCA Chemical Co., Ltd.), which is a cationic compound, was padded (squeezing ratio: 40%) and dried (100°C). Next, as a disperse dye, 20% of CIDisperse Blue 87 was added as a dispersant shown in formula 1 to the dye.
%, ion-exchanged water was added to bring the total volume to 200 c.c., and then 200 c.c. of glass beads (1 mmφ) were added, followed by dispersion treatment in a sandcliner for 30 hours. For comparison, the same dispersion treatment was carried out without adding a dispersant and using naphthalene sulfonic acid soda formalin condensate ("Demol N" manufactured by Kao Corporation) as a dispersant at 50% and 150% of the dye. The average viscosity determined by centrifugal sedimentation was 0.2μ. Next, a wetting agent shown in Table 1 was added to this liquid at the following composition ratio to prepare a disperse dye ink. For comparison, disperse dye inks were similarly prepared using wetting agents other than those of the present invention (shown in Table 1). CIDisperse Blue 87 (20%) 50% Wetting agent 20% EDTA/2Na salt 0.2% Ion exchange water 29.8%

【table】

【table】

[Formula] These ink viscosity (EMD viscometer, rotation speed
150 rpm, temperature 35℃) are shown in cps, and in order from the top (1,3 butanediol),
2.9.3.2.3.2.2.8.2.8.2.9.3.5 and 3.4. Filter this ink with a 5 μ cut filter,
The dispersibility was determined from the residue. Here, the dispersibility is an evaluation method in which the dye dispersion rate T (%) determined from the following formula is evaluated in five stages as shown in Table 2. T: Dye dispersion rate T=M-m/M×100 M: Weight of dye in original ink m: Weight of dye on filter paper

[Table] After being allowed to stand for another 3 weeks (35°C), it was similarly filtered using the above filter to determine the dispersibility. The results are shown in Table 3. After degassing under reduced pressure using this ink, printing was carried out under the following ink jet conditions. Method: On-demand Nozzle diameter: 60μ Applied voltage: 50V Distance between nozzle and fabric: 1mm To check the dryness and clogging of ink at the nozzle tip of an inkjet printer, the nozzle is left without a cap and ink can be ejected. The standing time was measured. The results are shown in Table 3. The ink was applied with an inkjet, and then fixed at 180°C with moist heat and steam for 10 minutes.
Made it color. The dot diameter of the dyed product was also measured. The results are shown in Table 3.

[Table] As shown in Table 3, the wetting agent of the present invention has good ink dispersibility even after being left for three weeks, and the ink does not become clogged even if the nozzle is left without a cap for more than 60 minutes. It was possible to dispense. Furthermore, there was no effect on the prevention of bleeding, and dyed products with clear and high-quality designs were obtained. On the other hand, diethylene glycol and glycerin, both of which have a small number of carbon atoms, as comparative examples, have low anti-drying ability, and the ink clogs after leaving the nozzle for just a few minutes. Furthermore, inks containing ethylene diglycol and butyl diglycol, which are alkyl ethers of alkylene glycol, caused significant aggregation of the dye and could not be used as inks. In addition, polyalkylene glycol PEG #400, solubilizing agent N-methyl-2
- The ink containing pyrrolidone also caused bleeding, which hindered the prevention of bleeding. That is, only the inkjet method of the present invention using an ink composition containing a C ₄ to _{C 6} diol was able to obtain a good dyed product. In addition, those that do not use a dispersant cannot be filtered, and anionic dispersants other than the present invention (Demol N)
When 50% was used, the dispersibility was poor, and when 150% was used, the dispersibility improved, but there was an issue where the nozzle dried easily due to insufficient standing time, and the dots were large in diameter on the cloth. Example 2 As a disperse dye, 20% of MiketonPoly Red BLSF (manufactured by Mitsui Toatsu) was dispersed using a sand grinder under the same conditions as in Example 1 for 30 hours. The average particle size determined by centrifugal sedimentation was 0.3μ. Next, 2.2 dimethyl 1.3 propanediol (neopentyl glycol) was added to this liquid in the proportions shown in Table 4 to prepare three types of disperse dye inks.

[Table] After this ink was filtered through a 5μ cut filter, the viscosity was measured under the following conditions. Viscometer EMD viscometer (manufactured by Tokyo Keiki) Rotation speed: 100 rpm Measurement temperature: 35° C. Using this ink, inkjet dyeing was carried out under the same conditions as in Example 1, and the time the ink could be allowed to stand was measured. The results are shown in Table 5.

[Table] As shown in Table 5, ink containing a small amount of wetting agent had almost no ability to prevent drying, and clogging of the ink occurred when left for 5 minutes or more. In addition, the viscosity of the ink increased, making it impossible to eject the ink. Example 3 Dispersion treatment was carried out in the same manner as in Example 1 using CI Despers Blue 87 as a disperse dye and the following three types of dispersants as dispersants. Dispersion treatment composition CI Despers, Blue 87 20 parts Dispersant 10 parts Antifoaming agent (acetylene glycol type) 0.1 part Ion exchange water
69.9 Partial dispersant A Dispersant B Dispersant C Next, a disperse dye ink having the following composition was prepared using this dispersion. Dispersion liquid (containing 20% dye) 40% Wetting agent (1,4 butanediol) 20% Ion-exchanged water 40% Using this ink, dispersibility and
The ink leaving time, ink viscosity, and dot diameter were measured.

[Table] All dispersant inks had good dispersibility and a good standing time of 60 minutes or more. (Effects of the Invention) The ink composition for ink jets of the present invention has no fear of causing troubles due to ink clogging, and can provide clear printed patterns and plain dyeing with a high-class feel, and has great practical value. It's big.

Claims (1)

[Claims] General formula as a dispersant Q is a benzene nucleus or a naphthalene nucleus, R ₁ is a group containing a benzene nucleus or a naphthalene nucleus, m is 2 to 5, R ₂ is a non-aromatic group such as lower alkyl or halogen, n is 0 to 3, and Z is A water-based medium ink containing finely dispersed water-insoluble dyes and pigments with an average particle size of 1μ or less using a compound represented by a divalent substituent, M represents ammonia, amine, or a monovalent metal. Contains 10-50% by weight of _C4 - _C6 diol and has a viscosity of 2-2 at 35°C.
An ink composition for an inkjet, characterized in that it has an inkjet density of 10 cps.