JPH0253976A - Dyeing of cloth - Google Patents

Abstract

PURPOSE:To improve the mixing of pigments on a cloth and increase the level- dyeing property and the adsorption of the pigment on the cloth in the ink-jet printing of a cloth by pretreating the cloth with a hydrotropic agent. CONSTITUTION:A cloth is pretreated with a treatment bath containing (A) a hydrotropic agent (e.g., urea, its derivative, thiourea or its derivative) and preferably (B) a non-dyeing polymeric substance (e.g., gum arabic, shellac gum or sodium alginate) and the treated cloth containing the hydrotropic agent is subjected to ink-jet printing. The adsorption of pigment to the cloth can be improved by this process to obtain a dyed cloth having uniform and dense color.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to fabric foil dyeing using the inkjet printing principle. Specifically, the present invention relates to improvements in so-called fixation, which improves the absorption of dyes onto the fabric during dyeing, and improvement in level dyeing properties, which improves the mixing of dyes on the fabric.

(Prior art and problems) Today, as fashion is diversifying, there is an extremely strong demand for high-mix, low-volume production. Conventional textile printing methods have complicated processes and require a great deal of cost and time, so it has become increasingly difficult to adapt to the demands of high-mix, low-volume production. In other words, the so-called printing method for dyeing patterns on cloth has come to be distinguished from screen printing, roller printing, and transfer printing over a long history.

Screen printing uses a thin fabric with a small grain called gauze (which includes silk, nylon, polyester, etc.) stretched over a frame similar to that seen in so-called mimeograph printing. This is called flat screen printing.

On the other hand, instead of gauze, a metal film with small holes is used in a cylindrical shape. This is called rotary screen printing. What they have in common is that they use a screen with uniform holes, and this single hole is the smallest unit of the design through which the printing paste passes. Therefore, if dotted prints are connected in a line, they form a line, and if they are connected in a plane, they form a field.

In this system, only one color of printing paste can be used on one (or one) screen, and if eight-color representation is desired, eight (or eight) screens are required.

Roller printing is based on the principle of etching a pattern onto a copper roll, filling it with printing paste, and transferring it onto a cloth. This method also allows only one color of printing paste to be used in one roll, and requires rolls for the number of colors desired.

Transfer printing is not a method in which the printing paste is directly transferred onto the cloth through a screen or roll, but a pattern containing the printing paste is transferred onto a paper called transfer paper using a printing method or a textile printing method, and then this is transferred onto the cloth. The principle is the so-called copying power test method in which the copying is done again.

Although this method appears to be simple as a textile printing method, the transfer paper manufacturing process still requires a long process compared to the conventional method.

In this way, textile printing is a technique for producing patterns that are created by combining ■design ■carving■printing paste■fabric, etc.
It takes too much money and time to prepare one.

In addition, the printed designs have strong artistic and craft elements, and before actual production, it is common to reproduce them on the same fabric in a small piece test and consider the design and color scheme. be. Therefore, even if it is undecided whether it will go into full production, the four preparations listed above must be done once. If the designer determines that the product does not match the concept at the stage of small piece testing, production will be halted and all preparations will be carried out.

In order to improve these problems, attention is being paid to the application of a technology that combines image processing and inkjet printing, known as computer graphics.

This method was developed in the field of paper recording and printing.
Many attempts have been made to apply this concept to fabrics, and many proposals have already been made to replace conventional printing methods.

However, these proposals do not go beyond the superficial imitation of conventional, established textile printing technology using inkjet inks and inkjet devices that have been established for paper, and from the perspective of those who are familiar with textile printing technology, All of these proposed techniques have many problems, and it can be said that no technique has been proposed that suits the characteristics of cloth foil.

The purpose of the present invention is to clarify the difference between textile printing technology and inkjet printing technology, and to propose an inkjet printing technology that exhibits a remarkable effect on textile printing. To this end, it is necessary to clarify the difference between paper/printing and cloth/printing.

1) Both tissue paper and cloth have in common that the smallest unit is a fine fibrous substance, but the former is characterized by its disordered structure because it is made by randomly intertwining these substances. be. The latter is made by intertwining or converging the fibers in a certain order (in the so-called longitudinal direction), and then weaving these as warp and weft yarns according to the weaving structure, or knitting them according to the knitting structure, resulting in structural is characterized by its orderliness.

2) Surface shape The surface of paper is generally smooth with no irregularities and no blank spaces for the purpose of writing letters or printing designs. On the other hand, as mentioned above, cloth foil is made using various threads according to a certain weaving and knitting structure, so its surface is generally uneven and uneven with gaps. 3) Wrapping method Various pigments are used on paper to print letters and designs, but these pigments are attached to the surface of the paper and held in place with a vehicle. Cloth foil uses various pigments to add colors and designs, but these pigments are used depending on the chemical structure of the cloth foil, and this method allows them to penetrate into the inside of the fibers that make up the cloth foil and become fixed. Take. The difference between the two is that paper is not supposed to get wet, while cloth foil is supposed to get wet. Although the molecular structure of each pigment has been elucidated, when these pigments are in a monomolecular state, they have true hue, but when they are in an aggregated state, the color becomes dull. If the dye is simply deposited, as in the case of paper, if the dye concentration is increased too much, this aggregation will occur and the color will become dull.

Therefore, the dye concentration cannot be set higher than the aggregate state.

On the other hand, in the case of cloth foil, high temperatures are applied to fix the pigments.
Using high pressure and chemical reactions, even if used in an aggregated state, it is finally made into a single molecule. Therefore, it is possible to use the dye at a high concentration, ignoring the aggregation state, as long as the solubility of the dye allows.

Looking more closely at the coloring method, in the case of paper, it is 100% effective when it is applied to the surface of the paper, but in the case of cloth foil, dry heat is the method used to dye it after it is applied to the surface of the cloth. ~ There is no wet heat treatment and cleaning. Only the dye that is strongly dyed on the surface and inside of the parenchymal fibers remains, and the rest falls off from the fibers.

In this way, in cloth, the pigment moves inside the fibers.
This results in a low concentration that is difficult to compare with paper due to the residual rate distributed throughout the focusing system.

In this way, I learned that there is a difference between printing/texturing on paper and cloth, but I am not satisfied with the level of inkjet printing on paper, and the level of inkjet printing on cloth is the same as that of conventional textile printing. Needless to say, it is far from satisfactory. Next, I will give an overview of inkjet printing on cloth and highlight its problems.

Inkjet printing on cloth uses a liquid containing pigment,
That is, the ink is made into granules and sprayed onto the fabric to be printed to temporarily fix the pigment. At this time, one particle is the smallest printing unit, and if this particle is considered spherical, its diameter is 10
The size should be from micron to 300 micron. Naturally, if this diameter is small, the area covered on the object to be dyed is small and many dots must be applied. However, it has the advantage of producing a pattern of thin lines and dots. On the other hand, if it gets bigger, the opposite will happen. If the particle liquid is considered to be a water droplet, one particle weighs 4.19 x 109 g at a diameter of 20 microns, and 1.13 x 10-7 g at a diameter of 60 microns. A dye is dissolved in the particles and has a concentration proportional to the weight of the particles.

For example, if dots are uniformly distributed over the entire surface, 20 points per 1σ2
Micron requires 62,000 grains, and 60 micron requires 16,000 grains. These particles are 7,000 to 150,000 particles/
It is launched at a speed of 1 minute. Therefore, the amount of application is given by the particle size x the number of dots, and the dye concentration on the object to be dyed is determined by three conditions: the concentration of the dye contained in one particle, the particle size, and the number of dots. It's obvious.

It has been explained that the smallest printing unit in inkjet printing is one small particle. These inks are stored in ink pots of at least four colors (in this case, yellow, red, blue and black), and each is applied via a nozzle.

For example, when expressing green, yellow ink and blue ink are counted at a ratio of 1:2 and dotted. These dots may overlap or be separated. Particularly in the latter case, if the dotted particles have a large area on the cloth and are separated, they will not be seen as a mixed color. This dot method applies the visual phenomenon of the human eye, and such color mixing is called juxtaposed additive color mixing.

Since inkjet printing uses this color mixing method to express colors, it is natural that when the pigment concentration in the ink pot is increased, the number of dots will be extremely reduced and the dots will become separated in order to express pale hues. It is necessary to adjust the pigment density of the ink fountain to suit the required hue and density.

The above is an explanation of one of the problems when expressing colors by mixing them, but the inventors of the present invention believe that dye density is the most important point when replacing inksheet printing with conventional cloth printing. Therefore, we considered this point.

Even if the required hue is obtained, it is not worth it if the density is 1/10 to 1/5. It is necessary to be able to reproduce all required concentrations.

On the other hand, if the amount of dissolved dye in one particle is large, the amount of ink to be dotted will be smaller than the density required for the dyed object, which is expected to improve printing speed and reduce bleeding. It is clear that At this point, I should add an explanation about stains on cloth. Bleeding is the biggest quality checkpoint for paper, but the same is true for cloth.

However, the bleeding on cloth is not as severe as on paper. As mentioned above, cloth foil has disadvantages compared to paper in terms of texture and surface elements, but as seen in conventional textile printing technology, countermeasures against bleeding are based on each fiber,
Considering that appropriate measures are being taken by each organization, smearing is not a problem that should be emphasized as much. However, in the case of bleeding, the cause of the bleeding should be identified and improvements can be made from the ink side, from the dyed object side, printing, etc.
Needless to say, appropriate measures such as improvement from the stuck side are necessary.

As mentioned earlier, since ink with a low concentration is used, it is natural that increasing the particle size and the number of dots will increase the amount of liquid and cause bleeding, but this is not the case when using ink with a high concentration. If so, it can be resolved immediately. Therefore, the most important point in inkjet printing for fabrics is how to increase the pigment concentration in the ink, but it is also important how to increase the residual rate.

(Means for Solving the Problems) The purpose of the present invention is to provide a method for effectively fixing the dye applied when inkjet printing the cloth foil, that is, to improve the so-called dye fixation rate, and to improve the so-called dye fixation rate on the cloth foil. It is an object of the present invention to provide a dyeing method that improves dye mixing and so-called level dyeing.

In the present invention, a hydrotrope is applied to an inkjet ink containing a water-soluble pigment or a water-insoluble pigment and/or a fabric to be dyed, and the pigment is applied to the fiber side by dry heat or warm heat treatment as a fixing process. This method smoothes the transition and ultimately improves the dye fixation rate.

With this dyeing method, mixing of pigments progresses during the printing to heat treatment process, and level dyeing properties are also improved.

By the method of the present invention, it is possible to improve printing speed, prevent blurring, save materials, and improve quality in inkjet printing on cloth. The cloth used here is made of cotton, linen, various types of rayon, silk, wool, polyamide fibers, various types of acetate fibers, and polyester fibers. Pigments include various acetates and polyester fibers, which are pigment components present in disperse dyes that are classified according to conventional dyeing science, and other fibers include reactive dyes, direct dyes, acid dyes, basic dyes, and fluorescent dyes. A pigment component present in dyes. Pigments used for general dyeing, so-called dyes, contain large amounts of impurities and additives from the manufacturing process, but this has hardly been considered a problem with conventional dyeing and printing methods. However, in inkjet printing, ink characteristic items such as specific electrical conductivity, surface tension, viscosity, and specific gravity, as well as their associated characteristics such as foaming, cohesiveness, wettability (penetration), and temperature stability, are important. The composition of the ink is important because of its phenomenal characteristics such as its properties. For this reason, it is necessary to first increase the purity of the dye, that is, to purify it. Addition of various chemicals to ink is severely restricted. This constraint must be compensated for by the subject.

The hydrotropic agent used in the present invention is commonly used in conventional printing methods, and its action is said to help dissolve dyes and prevent dye aggregation, which is known to lead to uniform printing and improved color yield. It is being These were generally used by being added to colored paste. However, the present invention does not mainly add it to the ink, which is comparable to colored paste, but
It is applied to the object to be dyed and is done as follows.

Examples of the hydrotrope include urea, monomethylurea, dimethylurea, thiourea, monomethylthiourea, dimethylthiourea, formamide, dimethylformamide, acetamide, and dimethylacetamide.

In addition to this, there is alcohol. Among these, urea is the most preferred in terms of economy. When using these hydrotropes, it is preferable to use a non-staining polymeric substance together.

A non-staining polymer substance does not mean that it does not stain the dye used at all, but it does not mean that it does not dye the dye used at all, but it does not mean that it does not dye the dye used at all. If one condition is satisfied, and furthermore, the dye transferred to the non-staining polymer substance does not have an adverse effect in the next step of color development, washing, etc., then the second condition is satisfied, and furthermore, if the loss of dye is economically worth it. This means that the third condition is satisfied.

Non-staining polymeric substances used in the present invention include gum arabic, guar gum, siraccum, locust bean gum,
There are sodium alginate, ammonium alginate, carboxymethyl cellulose, carboxymethyl starch, etc., and these are dissolved in water and applied to the object to be dyed by means of vat method, coating method, or screen method under appropriate viscosity and drying and fixing. When preparing the formulation using the pat method as a standard, it is preferable that the number of parts of the polymer substance (X) and the number of parts of the hydrotrope (y) do not fall within the indicated ranges.

Polymer substance 0.1≦X≦5 And the dry solid amount on the object to be dyed is 300% of the weight of the object to be dyed.
It is preferable to keep the amount below the weight percent.

The dyed object treated in this manner is stored without any creases to prevent it from absorbing moisture.

It is preferable that the hydrotrope is also applied to the ink. The amount should be kept below 20% by weight of the ink liquid weight. However, the effect obtained does not depend on the addition of ions to the ink unless the solubility of the dye is small.

A third substance may be added to the ink or/and fabric stocking agent for the following purposes.

Preservative: To prevent the glue used from spoiling.

Anti-reducing agent: To prevent the reduction phenomenon that occurs when various pigments are exposed to high-temperature dry heat or high-temperature moist heat. For example, MS powder fixation aid: To prevent the transfer of various pigments onto fibers and to improve fixation. For example, neutral salt fixation reactants such as table salt and sulfur salt: To promote fixation of various pigments on fibers.

For example, acid, alkali fixation promoter: A chemical with high fiber swelling ability that enhances the fixation of various dyes to fibers (Example) Further explanation will be given below with reference to Examples. The inkjet device uses an on-demand recording method and has a nozzle diameter of 60 mm.
μm1 applied voltage 107 volts, resolution 180 dots/
It is 1n. The printing method is a 4×4 matrix.

Example 1 A 60 count mercerized cotton cloth is prepared. Duck algin M
(Kamogawa Chemicals) 1 part, reagent sodium carbonate 3 parts, urea 5 parts
A treatment solution was prepared with 91 parts of water and 91 parts of water, vatted at 3 kg/cr/, and then dried at room temperature. The dry solid content was 15%.

CI Reactive Red 24 was dissolved in ion-exchanged water to give an ink with an optical density of 10,000. After making dots with an inkjet printer, it was treated with saturated steam at 103°C for 20 minutes, washed with a soaping liquid containing an anionic activator at 80°C for 10 minutes, and dried.

As a comparative product, a processing solution was prepared in which urea was omitted from the above-mentioned bat solution and treated in exactly the same way as a comparison material.

The dyed fabric obtained through this process is even and deep,
The reflectance was 6.00% at an absorption wavelength of 520 mμ. The comparative product was dyed with less uniformity and depth than the inventive product, and had a reflectance of 8.50%.

Example 2 65g/inylon taffeta was prepared. Make a treatment solution with 2 parts of Duck Algin M (Kamogawa Kasei), 3 parts of ammonium sulfate reagent, 3 parts of urea, and 92 parts of water to produce 3 kg/c rt.
Pad under and dry at room temperature. The dry solid content was 4%.

CI Ac1d Yellow 110 was dissolved in ion exchange water to give an ink optical density of 0.13 million. The following treatment was carried out in the same manner as in Example 1.

The dyed fabric obtained by this treatment was uniform and deep, and had a reflectance of 4.50% at an absorption wavelength of 420 mμ. The comparative product was dyed with less uniformity and depth than the inventive product, and had a reflectance of 5.81%.

Example 3 A 124 g/m' polyester interlock is prepared. Methylhydroxyethylcellulose (Daiichi Kogyo Seiyaku)
A coating solution was prepared using 4 parts of acetic acid, 0.05 parts of acetic acid, 10 parts of urea, and 85.95 parts of water, and after printing with a 1500 mesh screen, it was dried at room temperature. The dry solid content was 13%.

CI D 1sperse Red 127 CI
Risperse Yellow 160 was adjusted to an ink optical density of 0.63 million, 0.005 part of glycerin, 0.01 part of sodium alginate,
1 part of sodium nitrohenzenesulfonic acid and 98 parts of water were used as an added ink.

Red: Yellow with inkjet printing machine
=2: ] (16 strokes, 16 parts) After making a point, it was treated with superheated steam at 175°C for 10 minutes, and reduced cleaning containing hydrosulfide, soda ash, and anionic activator was performed at 80°C.
for 10 minutes, then washed with water and dried.

As a comparative product, a sample was prepared by omitting urea from the above-mentioned coating solution, and was treated in exactly the same manner for comparison.

The dyed fabric obtained through this process is even and deep,
The reflectance was 6.82% at an absorption wavelength of 520 mμ.

The comparison product had a reflectance of <7.77%, which was the same as the dyed fabric lacking uniformity and depth compared to the product of the present invention.

As shown in the main text and examples, the present invention can solve the problem of insufficient density and level dyeing of colored products caused by the principle of inkjet printing, and contributes to the expansion of fabric foil dyeing.

Claims (5)

[Claims] (1) When performing inkjet printing on cloth foil,
A method for dyeing cloth foil, characterized by applying a hydrotrope to the cloth foil in advance and performing a printing process. (2) The method according to claim 1, wherein the hydrotrope is one or more of urea or its derivatives, or thiourea or its derivatives. (3) The method according to claim 1, wherein the hydrotrope is one or more of formamide or a derivative thereof, or acetamide or a derivative thereof. (4) The method according to claim 1, in which the hydrotrope according to claim 2 and the hydrotrope according to claim 3 are used together. (5) The method according to any one of claims 1 to 4, wherein the cloth is also coated with a hydrotrope agent in advance.