JP3053925B2 - Inkjet printing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for printing textiles (woven or non-woven fabric) by an ink jet system utilizing thermal energy, and relates to a method of printing a clear and delicate pattern when using a textile containing cellulosic fibers. The present invention relates to an ink-jet printing method to be expressed.

[0002]

2. Description of the Related Art At present, the mainstream of printing is screen printing,
Roller printing. These methods are unsuitable for high-mix low-volume production, and it is difficult to respond quickly to fashion trends. Recently, it has been demanded to establish a plateless electronic printing system. In response to this demand, a number of printing methods using ink jet recording have been proposed, and expectations from various fields have increased.

[0003] The problems of ink-jet printing include:
(1) To give a sufficient density for color development, (2) To not clog the nozzles of the head, (3) To dry the ink quickly on the fabric, and (4) To reduce irregular bleeding on the fabric. (5) that the ink does not change its physical properties or precipitate solids during storage, and (6) that there is no change in ejection characteristics even during long-term durability.
In the method of ejecting ink using a volume change due to heat energy described in Japanese Patent Application Laid-Open No. 4-59936, there is no deposition of foreign matter on a heater that applies heat energy, and the heater is destroyed by cavitation at the time of defoaming. Does not occur, (7) the process is simpler,
And the like.

In order to satisfy these problems, the following measures have been conventionally taken. First, for (1), a general means is to give a sufficient density by increasing the density of the dye in the ink.
This is an indispensable technique when using small droplets of 0 pl or less or for fabrics having strong absorption power. However, when such an ink is used, the ink is thickened due to evaporation of the ink from the nozzle tip, or a solid dye is deposited to cause the problem (2). For this reason, measures such as adding a polyhydric alcohol such as glycerin to the ink have been taken for (2). However, when the dye concentration exceeds 5%, a solution that can be said to be particularly complete is used. There is no solution and no satisfactory results can be obtained except for a very specific combination of dye and solvent.
Regarding (3), the effect of the water repellency of the fabric is large, but no particular problem occurs when, for example, a water-based ink is used for a fabric mainly composed of cellulose fibers. Regarding (4), many proposals have already been made for inks. For example, in JP-A-61-231289, tannin is added, and in JP-A-62-283174, addition of a carboxylic acid group-containing polymer to the ink is mentioned. However, in each case, the problem (2) cannot be avoided. Regarding (5) and (6), there are cases where the problems are caused by the structure of the dye or the influence of the pH of the ink. However, detailed studies have not been made and the problem has not been sufficiently solved. The method (7) is much simpler than the conventional method because of no plate-making, but there is room for contrivance as to in which step the alkali treatment is performed.

As described above, in the prior art, means for individually satisfying individual performances can be found, but an ink-jet printing method which simultaneously satisfies these performances and solves a series of such problems has been hitherto known. There is no present.

[0006]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to limit the fabric to be dyed to a fabric mainly composed of cellulose fibers, and to solve the problems of the conventional general ink jet printing as described above, namely, To provide a printing method that simultaneously satisfies the dyeing problem of obtaining a clear and high-concentration dyed product and the discharge performance problem that enables stable and reliable printing over a short or long period of time. It is. The object of the present invention is achieved by the following present invention.

[0007]

That is, the present invention provides (a) a step in which small droplets of a printing ink are caused to fly by applying thermal energy to a fabric mainly composed of cellulose fibers, and (b) a process in which the fabric is heat-treated. An ink jet printing method comprising at least three steps of dyeing the dye in the ink thereon and (c) washing the undyed dye, wherein the printing ink is 5 to 30% by weight of dichlor. A reactive dye having no triazine group, an alkaline substance and an aqueous liquid medium, wherein at least 5
An ink jet printing method characterized by using an ink having a pH of 9 or more containing チ オ 50% by weight of thiodiglycol.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, in the present invention, in ink-jet printing,
Focusing on the ink having a large influence, the ink was improved to simultaneously satisfy the various required performances as described above. As a result, a certain amount of thiodiglycol was added to the high-concentration aqueous ink using 5 to 30% by weight of the reactive dye. It has been found that the coloring properties such as leveling property and dyeing rate can be remarkably improved by adding. This phenomenon is thought to be due to the fact that thiodiglycol has some effect to maximize the reaction characteristics of the dye at the molecular level.

Further, it has been found that by incorporating thiodiglycol, this dye system can provide a long-term stable discharge characteristic which could not be considered with conventional solvents. This effect is particularly remarkable when an inkjet head using thermal energy is used. The reason for this is that the interaction between the reactive dye and thiodiglycol suppresses the formation of deposits on the head. It is conceivable that the ink thickening at the nozzle tip portion is specifically suppressed in this combination.

[0010] In addition, even when the pH of the ink is 9 or more except for a specific reactive group, the hydrolysis of the dye is slight at the practical use level in a factory, and no decrease in the dyeing rate of the ink is observed. did.

[0011]

The ink jet printing ink used in the present invention comprises at least 5 to 30% by weight of a reactive dye having no dichlorotriazine group and an aqueous liquid medium, and contains an alkali substance and a certain amount of thiodiglycol. It is characterized by containing.

The substance which primarily characterizes the ink used in the present invention is thiodiglycol, and its content in the ink is 5 to 50%, preferably 7 to 45%, and more preferably 10 to 45%. It is in the range of 40%. When the content of thiodiglycol is 5% or less, not only the effect of improving the coloring property is insufficient, but also deterioration of the storage stability of the ink and non-ejection due to thickening due to ink evaporation near the nozzle tip are caused. . If the content exceeds 50%, the storage stability of the ink deteriorates similarly to the case of 5% or less, in addition to the problem of the color development. Regarding the ejection characteristics, the response to the frequency is extremely deteriorated. In addition, a problem of non-discharge in a short-term leaving state also occurs with an increase in initial viscosity of the ink. As the dye to be used, almost any type can be used as long as it is a reactive dye having no dichlorotriazine group, but a dye having a monochlorotriazine and a vinylsulfone group is particularly preferable.

Specific examples include, but are not limited to, these dyes. I. Reactive Yellow 2,1
5, 37, 42, 76, 95 C.I. I. Reactive Red 21, 22, 24, 33, 45, 111, 112,
114, 180, 218, 226 C.I. I. Reactive Blue 15,19,21,38,49,72,7
7, 176, 203, 220 C.I. I. Reactive blacks 5, 8, 31, 39 and the like. The amount of these dyes used is generally 5 to the total amount of the ink.
-30% by weight, preferably 6-25% by weight, more preferably 8-20% by weight.

Water, which is an essential component of the ink, is 30 to 95% by weight, preferably 40 to 9% by weight, based on the total amount of the ink.
0% by weight, more preferably 50 to 85% by weight. Although the above are essential components of the ink used in the present invention, a common organic solvent can be used in combination with thiodiglycol. For example, ketone or keto alcohols such as acetone and diacetone alcohol; tetrahydrofuran,
Ethers such as dioxane; oxyethylene or oxypropylene addition polymers such as diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, polyethylene glycol and polypropylene glycol; ethylene glycol, propylene glycol, trimethylene glycol; Alkylene glycols having an alkylene group containing 2 to 6 carbon atoms, such as butylene glycol, 1,2,6-hexanetriol and hexylene glycol; glycerin; ethylene glycol monomethyl (or ethyl) ether, diethylene glycol monomethyl (or ethyl) Lower alkyl ethers of polyhydric alcohols such as ether and triethylene glycol monomethyl (or ethyl) ether Triethylene glycol dimethyl (or ethyl) ether, tetraethylene glycol dimethyl (or ethyl) lower dialkyl ethers of polyhydric alcohols such as ether; sulfolane, N- methyl -
2-pyrrolidone, 2-pyrrolidone, 1,3-dimethyl-
2-imidazolidinone and the like.

The content of the water-soluble organic solvent is generally in the range of 0 to 50%, preferably 2 to 45% by weight based on the total weight of the ink.

When the above-mentioned media are used in combination, they can be used alone or as a mixture. The most preferred liquid medium composition is one in which the solvent contains at least one polyhydric alcohol and its derivative. Among them, diethylene glycol, triethylene glycol, triethylene glycol monomethyl ether and tetraethylene glycol dimethyl ether are particularly preferable.

As for the other contained substances, it is preferable to add 1 to 30 ppm of calcium and / or magnesium within a range that does not cause clogging, because the coloring properties such as leveling property and dyeing rate can be further improved. Further, by containing a substance of the group consisting of silicon, iron, nickel and zinc in an amount of 0.3 to 10 ppm, more stable ejection characteristics can be obtained for a long period of time. It is also good to add a small amount as necessary. This effect is particularly remarkable when an ink jet head utilizing thermal energy, which is a feature of the present invention, is used. The reason for this is that excessive inclusion of these substances causes a decrease in foaming power due to deposits on the head, but formation of deposits by moderate addition causes cavitation during defoaming without causing a decrease in foaming power. Relaxing and preventing disconnection. The main components of the ink used in the present invention are as described above, but other various dispersants, surfactants, viscosity adjusters, surface tension adjusters, fluorescent brighteners, etc. are required as long as clogging does not occur. It can be added according to.

For example, viscosity modifiers such as polyvinyl alcohol, celluloses and water-soluble resins; various anionic, cationic or nonionic surfactants; surface tension modifiers such as diethanolamine and triethanolamine; buffers; And the like.

The outline of the constitution of the ink used in the present invention is as follows.
As mentioned above, the pH is adjusted to 9 or more, preferably 9.5 or more, more preferably 10 or more by adding an alkali agent such as sodium hydroxide, lithium hydroxide, or sodium hydrogen carbonate at the end of the ink adjustment. . The ink is preferably used within 24 hours after production, more preferably within 8 hours.

If the ink used in the present invention is used, the use of an alkali-treated fabric and the treatment with an alkali pad are unnecessary, so that the printing process can be greatly simplified.

The ink-jet printing method of the present invention is a method using the above-mentioned ink, and the ink-jet recording method is, for example, a method described in JP-A-54-59936. In this method, the volume of the ink that has undergone the action of thermal energy changes abruptly, and the ink is ejected from the nozzles by the action force caused by the change in the state. By using the above-mentioned ink in such a system, even if recording is performed continuously for a long time, deposition of foreign matter and disconnection at the heat generating head do not occur, and stable printing is possible.

This method is considered to be the most suitable method for ink-jet printing, although the restrictions on the ink are particularly severe, since it is easy to form multiple nozzles and it is possible to perform high-speed printing with a wide width.

In particular, the conditions under which the above ink is used and a particularly effective printing method can be obtained are as follows:
It is preferable that the range is 200 pl, the ink ejection amount is 4 to 40 nl / mm ² , the driving frequency is 1.5 KHz or more, and the head temperature is 35 to 60 ° C.

The fabric used in the present invention is limited to those mainly composed of cellulose fibers.

With the above structure, the printing ink is applied onto the cloth, but in this state, the dyeing is insufficient. Therefore, a step of heat-fixing the dye to the fiber by heat treatment and a step of removing the dye are essential. Such a method of fixing the reaction and removing the unreacted dye may be a conventionally known method.
After the treatment by the steaming method, the HT steaming method, the thermofix method or the like, the washing can be performed according to a conventionally known method of washing.

[0026]

Next, the present invention will be described more specifically with reference to examples and comparative examples. First, the ink used in the present invention will be described. The parts in the text and% are based on weight. Ink example 1

[0027]

[Table 1] Mix all the above components and adjust the pH of the mixture with sodium hydroxide.
After adjusting to 10.3 and stirring for 2 hours, the mixture was filtered with a Fluoropore Filter FP-100 (trade name, manufactured by Sumitomo Electric Industries, Ltd.) to obtain an aqueous ink (A).

Ink Example 2

[0029]

[Table 2] A water-based ink (B) was obtained in the same manner as in Ink Example 1 except that all the above components were used.

Ink Example 3

[0031]

[Table 3] A water-based ink (C) was obtained in the same manner as in Ink Example 1 except that all the above components were used.

Ink Example 4

[0033]

[Table 4] A water-based ink (D) was obtained in the same manner as in Ink Example 1, except that all the above components were used.

Ink Example 5

[0035]

[Table 5] A water-based ink (E) was obtained in the same manner as in Ink Example 1 except that all the above components were used.

Ink Example 6

[0037]

[Table 6] A water-based ink (F) was obtained in the same manner as in Ink Example 1 except that all the above components were used.

Ink Example 7

[0039]

[Table 7] A water-based ink (G) was obtained in the same manner as in Ink Example 1 except that all the above components were used.

Examples and Comparative Examples Each of the aqueous inks (A to G) of Examples 1 to 7 was prepared according to JP-A-54-5.
No. 9936, a head for a color bubble jet copier Pixel pro (trade name, manufactured by Canon) which is an ink jet head by the action of heat energy (number of nozzles: 256, flying droplets: 20 to 40 pl) is used. When continuous printing of 5 × 10 ⁸ pulses was performed with the number of nozzles, it was examined whether or not the nozzles were clogged, the amount of ejected droplets, the decrease in ejection speed, and the like. Also, after printing alphanumeric characters continuously for 3 minutes with the same head, stop printing, leave it for 3 minutes without the cap, print the alphanumeric characters again, and check for any character blurring or chipping. Examined. Further, after printing the alphanumeric characters continuously for 3 minutes with the same head, the printing was stopped, and the system was allowed to stand for 1 day without the cap, and clogging due to the adhesion of solid matter near the tip of the nozzle was examined.
(Each head was heated to a temperature in the range of 45 to 60 ° C.) Further, 100 cc of each aqueous ink (A to G) was placed in a glass bottle and stored at 40 ° C. for 1 day, and the storage stability of the ink was examined. Was. Table 1 shows the evaluation results of the inks.

Further, the aqueous inks (A to G) of Examples 1 to 7 were mounted on a color bubble jet copier Pixel pro (trade name, manufactured by Canon Inc.), and printed on a georgette fabric made of 100% cotton. Fixing was performed by steaming for 2 minutes, followed by washing with a neutral detergent, and the clarity and bleeding of the dyed product were evaluated. Table 2 shows the results. (The print was made of a 2 × 10 cm solid sample under the conditions of an ink ejection amount of 16 nl / mm ^2. )

[0042]

[Table 8] * 1: Number of nozzles that did not cause clogging of the nozzles, decrease in the amount of ejected droplets, or decrease in the ejection speed when continuous printing of 5 × 10 ⁸ pulses was performed with 10 nozzles. 〇: 10 lines Δ: 6 to 9 lines ×: 5 lines or less * 2: After continuous printing for 3 minutes, left for 3 minutes without capping and reprinted. 〇: No defective part from the first character. Δ: Part of the first character is blurred or chipped. X: Printing cannot be performed at all from the first character. * 3: After continuous printing for 3 minutes, clogging due to solid matter adhering near the nozzle tip when left for 1 day without capping. 〇: No clogging. Δ: Clogged, but recovered by suction. X: The clogging is not recovered by suction. * 4: After storing the ink at 40 ° C. for 1 day, it was visually determined whether or not foreign matter was generated in the glass bottle. 〇: No foreign matter △: Small foreign matter generated ×: Large foreign matter generated

[0043]

[Table 9] * 1: Judgment was made based on the sharpness of the pattern when observed with the naked eye. ：: good Δ: slightly poor ×: poor * 2: Observed with the naked eye. ：: good △: slightly poor ×: poor

[0044]

As described above, according to the ink jet printing method of the present invention, a clear and high-density dyeing product without bleeding can be obtained with respect to a fabric mainly composed of cellulose fibers. It becomes possible. Further, according to the ink of the present invention, in ink-jet printing, it is possible to perform printing with high reliability of ejection performance without causing clogging or the like in a head nozzle. In particular, in recording of a type in which the ink is ejected by a bubbling phenomenon of the ink due to thermal energy, it is remarkably excellent.

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinichi Sato 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (56) References JP-A-54-18975 (JP, A) JP-A-63 -68680 (JP, A) JP-A-1-213376 (JP, A) JP-A-1-263169 (JP, A) JP-A-1-263166 (JP, A) (58) Fields investigated (Int. . ^7, DB name) D06P 5/00 111 B41M 5/00 C09D 11/02

Claims (1)

(57) [Claims] 1. A process in which small droplets of printing ink are caused to fly by applying thermal energy to a fabric mainly composed of cellulose fibers, and (b) a dye in the ink is dyed on the fabric by heat treatment. And (c) a step of washing the undyed dye.
0% by weight of reactive dyes without dichlorotriazine groups,
An ink-jet printing method comprising using an ink composed of an alkaline substance and an aqueous liquid medium and containing at least 5 to 50% by weight of thiodiglycol in the liquid medium and having a pH of 9 or more.