JPH055953B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Field of Application) The present invention relates to fabric dyeing using the inkjet printing principle. More specifically, the present invention relates to a method for increasing the residual rate of ink on the fabric sheet and improving dye fixation on the cloth sheet when fabric dyeing is performed using the principle of inkjet printing. (Prior art and problems) Today, with the diversification of fabrics, there is an extremely strong demand for high-mix, low-volume production. Conventional textile printing methods involve complicated processes and require a great deal of cost and time, making it difficult to produce high-mix, low-volume production. It is becoming increasingly difficult to adapt to the demands of the world. 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 (this 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 method, only one color printing paste can be used on one screen (or one screen), and if eight colors are desired, eight (or eight) screens can be used.
) 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 the fabric. 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 a method in which the printing paste is not directly transferred onto the cloth through a screen or roll, but rather a pattern containing the printing paste is transferred onto paper called transfer paper using a printing method or a textile printing method, and this is transferred onto the cloth again. The principle is the so-called Utsugi-e method of copying. Although this method appears to be simple as a textile printing method, the transfer paper manufacturing process still requires completely conventional processes. In this way, textile printing is a pattern manufacturing technique that is created by combining design engravings, printing paste, fabric, etc., and the preparation of these four elements requires an enormous amount of money and time. In addition, printed designs have strong artistic and craft elements, and it is common practice to reproduce them on the same fabric in a small piece test before actual production, and to consider what design and color scheme should be used. 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 design does not match the concept during the small piece testing stage, production will be halted and all preparations will be carried out. In order to solve these problems, attention is being paid to the application of computer graphics, a technology that combines image processing and inkjet printing. This method was developed in the fields of paper recording and printing, and many attempts have been made to apply this concept to textile printing, and many proposals have already been made to replace traditional printing methods. ing. However, these proposals use inkjet inks and inkjet devices that have been established for paper, and do not go beyond the superficial imitation of established textile printing techniques. As can be seen, 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 remarkable effects on textile printing. To this end, it is necessary to clarify the differences between paper/printing and cloth/printing. (1) Structure Both paper and cloth have in common that the smallest unit is a fine fibrous substance, but the former is made by randomly intertwining these substances, so it is structurally disordered. It is a characteristic. The latter is made by intertwining or converging the fibers in a certain order (in the so-called longitudinal direction), and then weaving them as warp and weft yarns according to the weave structure, or knitting them according to the knitting structure. It is characterized by its structural order. (2) Surface shape The surface of paper is generally smooth with no irregularities and no blank spaces for the purpose of writing characters or printing designs. On the other hand, as shown above, cloth foil is made using various threads according to a certain weaving and knitting structure, so its surface is generally uneven, has voids, and is not smooth. 3) Coloring method Various pigments are used to print letters and designs on paper, but these pigments are attached to the surface of the paper and fixed with a vehicle. Various pigments are used to add colors and patterns to cloth foil, but these pigments are used depending on the chemical structure of the cloth foil, and are used to penetrate into the fibers that make up the cloth foil and become fixed. Take a method. 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 their true hue, but when they are in an aggregated state, the color becomes dull. If the dye concentration is increased too much when the dye is simply deposited as in the case of paper, this aggregation will occur and the color will become dull. For this reason, the dye concentration cannot be set higher than the aggregate state. On the other hand, in the case of cloth foil, high temperatures and high pressures are used to fix the pigments, and chemical reactions are also used, so that even if the pigments are used in an aggregated state, they are ultimately made into monomolecular forms. 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. If we take a deeper look at the coloring method, in the case of paper, it is 100% effective if it is applied to the surface of the paper, but in the case of cloth foil, it is applied to the surface of the cloth and then dyed. Due to the dry heat to wet heat treatment and washing, only the dye that is firmly dyed on the surface and inside of the actual fiber remains and falls off from other fibers. Thus, in fabrics, the pigment is distributed throughout the converging threads, which migrate into the interior of the fibers. This results in a low density that is difficult to compare with paper due to the residual rate and other reasons. In this way, it has been clarified that there is a difference between printing/textile printing on paper and cloth, but inkjet printing on cloth cannot meet the inkjet printing level of paper, and does not meet the same level as conventional textile printing. Needless to say, it should be done in a way that satisfies the requirements. Next, I will provide an overview of inkjet printing on cloth and highlight its problems. In inkjet printing on cloth, a liquid containing a pigment, ie, ink, is granulated and sprayed onto the cloth, which is the printing material, to temporarily fix the pigment. At this time, one particle is the smallest printing unit, and if this particle is considered to be spherical, its diameter is from 10 microns to 300 microns.
Make it micron. If this diameter is small,
Naturally, the area covered on the object to be dyed must be small and many dots must be applied. However, it has the advantage of producing thin line and dot patterns. On the other hand, if it gets bigger, the opposite will happen. Now, if we consider the particle liquid as a water droplet, one particle has a diameter of 4.19×10 ^-9 at a diameter of 20 microns.
g, 60 micron diameter is 1.13×10 ^-7 g. A dye is dissolved in the particles and has a concentration proportional to the particle weight. For example, if dots are uniformly distributed over the ^entire surface, 62,000 grains are required for 20 microns per square centimeter, and 16,000 grains are required for 60 microns per square centimeter. These particles are ejected at a speed of 7,000 to 150,000 particles/min. Therefore, the amount applied is given by the particle size x the number of dots, and the dye density on the dyed object is 1.
The concentration of pigment contained in each particle, the size of the particle,
It is clear that the decision will be made by three factors: number of runs batted in. It has been explained that the smallest printing unit in inkjet printing is one small particle. These inks have at least four colors (in this case yellow,
Red, blue, black, etc.) are stored in ink pots, and dots are applied to each via a nozzle. For example, when expressing green, yellow ink and blue ink are counted and printed at a ratio of 1:2. 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 dotting method applies the visual development of the human eye, and such color mixing is called juxtaposed additive color mixing. Since inkjet printing uses such a color mixing method to express colors, it is natural that the number of dots will be extremely reduced and the dots will be separated in order to express Usui's pale hue when checking the pigment concentration of the ink fountain. It is necessary to adjust the pigment density of the ink fountain to suit the required hue and density. The above describes one of the problems when expressing colors by mixing them, but when applying inkjet printing to fabrics to replace conventional textile printing, dye density is the most important point. This is because the key to color expression is the hue mentioned above and the density mentioned here. Even if the requested hue is obtained, the density is 1/10 or more
1/5 isn't worth it. All required concentrations should be reproducible. On the other hand, it is obvious that if the amount of dissolved dye in one particle is large, the amount of ink applied to the dyed object will be smaller than the required density, and it is expected that bleeding will be reduced. be. At this point, I should add an explanation about the bleeding in cloth. Smearing is the biggest quality check point 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 over paper in terms of structure and surface elements, but as seen in conventional printing technology, proper measures are taken for each fiber and each structure to prevent bleeding. From this point of view, bleeding is not a problem that should be emphasized as much. However, in the case of bleeding, it goes without saying that it is necessary to identify the cause of the bleeding and take appropriate measures such as improvements from the ink side, the dyed object side, printing, and fixing side. As mentioned earlier, since ink with a low concentration is used, the liquid volume can be reduced by increasing the particle size and the number of dots.
It goes without saying that as the amount of ink increases, bleeding becomes more likely to occur, but this can be quickly resolved by using ink with a high density. Therefore, the most important point in fabric inkjet printing is how to increase the pigment concentration in the ink.
It is also important to consider how to increase the residual rate. When inkjet printing is applied to paper, it is customary to specify and use paper with particular consideration for its structure, thickness, additives, surface coating agents, etc. in order to avoid bleeding. As mentioned above, cloth foil is different from paper in many respects. When performing inkjet printing on cloth foil, the cloth foil is fixed in advance onto a rubber plate, resin plate, film, paper, etc., but at this time, the ink passes through the cloth foil and reaches these supports. It's coming to an end. This is, of course, ink loss, which reduces the residual rate of ink on the cloth, and furthermore, the movement of ink across the support will appear as smearing, and the movement of ink on the support will appear as moire. This will encourage the phenomenon. SUMMARY OF THE INVENTION An object of the present invention is to provide a method for dyeing cloth by inkjet printing to maximize the residual rate of ink on the cloth. (Means for Solving the Problems) The present invention, when performing inkjet printing on a cloth sheet, coats the entire cloth sheet or the surface to be printed with a non-dyeable polymer compound to form a film. The non-printing surface of the cloth, which is opposite to the surface to be printed, is coated with a polymer compound to form a film to prevent ink from flowing to the non-printing surface. This is a cloth foil dyeing method in which the cloth foil is subjected to a printing process. First, the procedure for dyeing cloth foil using the inkjet printing method will be explained. (1) Design A computer graphic device reads the desired design source, such as a pattern on paper, a pattern on cloth, a pattern on film, or a plain color, and then layouts and modifies the pattern to give color instructions. . (2) Cloth foil The desired cloth foil is processed under appropriate scouring and setting conditions, and then pre-treated to improve printing and prevent smearing in the form of a spread cloth, with no wrinkles or curling. Dry as desired. (3) Ink Fill the device with the type of ink that is compatible with the desired fabric. (4) Printing Printing is performed according to the instructions of the computer graphics device. (5) Post-processing Perform fixation processing determined by the cloth and ink used. Next, cleaning is performed to remove unfixed and pretreated substances. Furthermore, as necessary, treatments to improve fastness (e.g., various fastness properties such as washing, friction, and light resistance), adjusting the texture of the fabric, and adding functionality (e.g., water repellency, static electricity, wrinkle resistance, etc.) Complete the finishing process. The cloth foil used in the present invention may be any of vegetable fibers, animal fibers, and artificial fibers. Each of these materials may be used alone or in the form of a blend, a mixed fiber, or a mixed weave of two or more types. The forms of cloth foil include woven fabric, knitted fabric, braided fabric, lace, net, and non-woven fabric. The dye used is
Using the names classified in conventional staining, the following apply: These include direct dyes, acid dyes, basic dyes, fluorescent dyes, disperse dyes, and reactive dyes.
These dyes are prepared for conventional dyeing and textile printing, and these dyes are used as main components in inkjet printing inks. Processing involves improving the dullness of the pigment, such as purification by removing by-products, impurities, additives, etc., and improving performance as an ink, such as adjusting particle size, viscosity, surface tension, specific conductivity, and PH. Pretreatment plays an important role in fabric dyeing using inkjet printing. This preprocessing has two main roles. One is to make the surface of the cloth as smooth as possible, and the other is to absorb and retain as much of the solvent present in the ink as possible. The ink supplied onto the fabric foil is retained within the fabric itself and the polymer compound used for this pretreatment, but if the amount of ink supplied exceeds this retention limit, a phenomenon of smearing occurs. On the other hand, the inkjet device tries to improve ink penetration by increasing the applied voltage to improve ink supply. This ensures that the ink passes through to the opposite side of the fabric foil to the printed side and deposits the ink on the support. The present invention performs preprocessing using two processing means. That is, a film is made with a non-dyeable polymer compound so as to cover the entire object to be dyed or to uniformly cover the printing surface, and the pretreatment portion will be explained in detail below. The non-dyeing compounds used here include gum arabic, guar gum, locust sting gum, shiratsu gum, sodium alginate, carboxymethyl cellulose, carboxymethyl starch, sodium polyacrylate, etc., which are most suitable depending on the fabric used and the pigment used. are selected, and it may be preferable to use a mixture of two or more types. Here, a non-staining polymer compound does not mean that it does not stain at all with the dye used, but it does not mean that it does not dye at all with the dye used, but if the desired density is obtained when dyeing the object with the dye concentration used. If the first condition is met, and the dye transferred to the non-staining polymer compound does not have an adverse effect in the next step of color development, washing, etc., then the second condition is met, and if the loss of dye is economically justified, then the second condition is satisfied. This means that the third condition is met. Water is mainly used as a solvent to dissolve this non-staining polymer compound, but in special cases
An organic solvent having a boiling point of 40° C. to 130° C. and a surface tension of 30 to 65 dynes/cm at room temperature is used. The following substances are optimally added. Preservative; Anti-reducing agent to prevent spoilage of the polymer processed materials used; For example, sodium metanitrobenzenesulfonate fixation aid to prevent various pigments from drying at high temperatures and reductive development that occurs during high-temperature and moist heat; fixation aid for various pigments on fibers. Prevents movement and promotes fixation. For example, neutral salt fixation reactants such as sulfur salt, common salt, and calcium chloride; promotes the fixation of various dyes on fibers; promotes the fixation of acidic substances such as acetic acid and ammonium sulfate; and alkali substances such as sodium bicarbonate and sodium hydroxide. Agents: Hydrotropes such as urea and thiourea, which increase the fixation of various dyes to the fibers, and moisturizing agents such as chlorobenzene and amikoic acid. It is applied so as to cover it, or it is applied so as to cover the surface of the object to be printed. Application methods for covering the entire object to be dyed include a pad method and spray method, and application methods for covering the printing side surface of the object to be dyed include a screen method, coating method, and spray method. Non-dyeable polymer compounds can be used on materials, the surface of single yarns,
The length of the single yarn, the number of single yarns, the thickness of the yarn, the processing of the yarn (e.g. twisting), the composition of the warp and warp, the density of the warp and warp, the voids in the structure caused by the balance of the warp and warp length of the final product, the unevenness of the structure, The amount applied depends on the thickness and other factors. Of course, the viscosity of the non-staining polymer compound in a dissolved state also influences the amount applied. The pad method consists of a dipping operation and a squeezing operation, but dipping and squeezing may be repeated multiple times to ensure uniform distribution inside the fabric. The padded cloth foil is handled in an expanded form and dried. The spray method is a method that applies pressure, and the viscosity used is smaller than that of the pad method, and is applied to one or both sides of a cloth. Post-processing to improve smoothness, such as calendering based on the press principle, is also added due to the unevenness and thickness of the tissue surface. Both the weight of the object to be dyed and the weight of the film were measured under absolutely dry conditions to eliminate the influence of moisture absorption by the film of the object to be dyed. In reality, the thickness of the film should be considered, but due to the special nature of using cloth, the gravimetric method was used instead. When the film produced by the above method is formed on the single threads or yarns constituting the object to be dyed, it may reach into the tissue voids. Naturally, the latter is the aim of the present invention, but it is desirable that the thickness of the film made of the non-dyeable polymer compound satisfies 1/100 to 1/2 times the thickness of the object to be dyed. At this time, the weight of the film is equal to the weight of the dyed product.
It is in the range of 1/200 to 1/4. For this purpose, for example, in the padding method, the viscosity of the solution to be padded is adjusted to 1 CPS to 100,000 CPS, and the squeezing rate is
Made under 50-130%. Application of the polymer compound to the non-printing side is done as follows. As the polymer compound used for this, the non-staining polymer compound used previously can of course be used, but the following polymer compounds can also be used. These include methyl cellulose, hydroxyethyl cellulose, acetyl cellulose, hydroxyethyl starch, acetyl starch, soybean starch, alginate propylene glycol ester, tamarind seed, polyvinyl acetate, polyvinyl alcohol, and the like. The reason why the polymer compound is expanded in this way is that the effect on dyeing is small because it reinforces the non-dyeable polymer compound on the film, and the viscosity restrictions are greatly expanded due to the method of applying it. It is from. Application methods include screen method, coating method, and spray method. In the case of the screen method, for example 15~
40 denier monofilament or multifilament warp density 30-400/in;
A plain woven fabric with a weft density of 36 to 370 threads/in is used as gauze. The viscosity of the polymer compound solution is 500CPS ~
At 100,000 CPS, the amount granted will be increased by squeezing once to several times. The coating method includes a knife floating method, a pipe coater method, a reverse slow coater method, and an over-knife coater method, and it is possible to obtain the same amount of coating as the screen method. The thickness of the film made of this polymer compound is preferably 1/2 to 20 times the thickness of the film on the printing surface. The weight of the coating at this time is in the range of 1/10 to 20 times the weight of the printing surface coating. After coating both, carefully dry in a dryer at a temperature of 100 to 150°C while adjusting the tissue density to avoid wrinkles or creases. Examples will be shown below. The inkjet printing device was an on-demand type with a nozzle diameter of 60 μm, an applied voltage of 107 volts, and a resolution of 180 dots/in4×4 matrix. For printing, all three ink pots in the printing device are filled with the same ink, and 16 dots are printed.
I made it possible to make 32 RBIs and 48 RBIs in the same place at the same time. The ink used was CI Reactive Red 24 dissolved in ion-exchanged water to give an ink optical density of 100,000. Here, the ink optical density is the value measured in a 10 mm sample cell of a spectrophotometer.
It is the value obtained by multiplying the concentration of the ink stock solution by the dilution factor to the concentration at the time of measurement, and is expressed at the maximum absorption wavelength value. Example 1 A rayon plain fabric that had been scoured and widened was prepared.
The density of this fabric is 130 diameter yarns/in and 86 weft yarns/in, and its weight is 56 g/ ^m2 , which is thin and has extremely poor ink absorption and retention. The fabric foil was padded with an aqueous solution consisting of 1% sodium alginate, 5% sodium bicarbonate, and 92% water and dried. The reduction rate was 64%.
This is a comparative product. Next, a coating solution of 21,000 cps was prepared with the same 3% sodium alginate and 97 parts of water, and coated and dried on one side of the pad-treated fabric using a 700 mesh screen. The weight of the film formed by padding was 1/10 times the weight of the dyed material, and the weight of the film formed by screen coating was three times the weight of the above film. Double-sided adhesive tape was placed around both items and they were fixed to the paper to avoid wrinkles. After printing
Steam for 10 minutes in a saturated steamer at 103°C, then wash in alkanesulfonate 0.2g/L soaping liquid.
It was treated at 70°C for 20 minutes, washed with water and dried. The results were as follows.

[Table] As seen in the examples according to the present invention, fabric dyeing based on the inkjet principle printing allows the jetted ink to remain on the dyed object side and provide high fixation. Since defects caused by leakage can be eliminated, high-quality fabric foil dyeing can be achieved.

Claims (1)

[Scope of Claims] 1. When performing inkjet printing on a cloth sheet, the entire cloth sheet or the surface to be printed is coated with a non-dyeable polymer compound to form a film, and the cloth sheet is further coated with a non-dyeable polymer compound. A fabric foil characterized in that the non-printing surface of the foil opposite to the surface to be printed is coated with a polymer compound to form a film, and then the fabric foil is subjected to a printing process. Dyeing method. 2 The weight of the film made of the non-staining polymer compound is
The method according to claim 1, wherein the amount is 1/200 to 1/4 times the weight of the dyed material. 3. The method according to claim 1, wherein the weight of the coating made of the polymer compound on the non-printing surface side satisfies 1/10 to 20 times the weight of the coating on the printing surface.