Process for procuding an Ink-jet printing cloth

Abstract: Disclosed herein is an ink-jet printing cloth which is dyed with inks containing a reactive dye and is composed mainly of silk fibers, wherein the cloth contains an alkaline substance in an amount of 0.01 to 0.8 % by weight based on the dry weight of the cloth.

Description: The present invention relates to ink-jet printing processes for producing an ink-jet printing cloth and an ink-set printed both. In particular, this invention relates to a process for producing an ink-jet printing cloth which is composed mainly of silk fibers having good stability with time, and is good in stability to coloring in high-temperature fixing and capable of providing highly colored, bright and fine patterns with high color yield upon formation of a print image by an ink-jet system, and a production process of a print using such a cloth. Related Background Art At present, textile printing is principally conducted by screen printing or roller printing. Both methods requires to form a plate, and are hence unfit for multi-kind small-quantity production and difficult to quickly cope with the fashion of the day. Therefore, there has recently been a demand for development of an electronic printing system making no use of any plate. In compliance with this demand, many textile printing processes according to ink-jet recording have been proposed. Various fields expect much from such textile printing processes even in dyeing on cloths composed mainly of silk. Ink-jet printing cloths composed mainly of silk and used in such a system are required to have the following performance characteristics: (1) being colored with an ink to a sufficient color depth; (2) being high in color yield of ink; (3) having no influence on mechanical properties and coloring properties during storage after a pretreatment; (4) causing little irregular bleeding of inks on the cloth; (5) being excellent in feedability in apparatus; and (6) being good in stability to coloring in high-temperature fixing. In ink-jet printing on cloths composed mainly of silk fibers, a system using inks containing an acid dye as a dye has heretofore been a mainstream. However, textile printing with reactive dyes is also required in a dyeing field of which high concentration and wet color fastness are required. An alkaline substance is indispensable for the use of the reactive dyes. When the silk fibers are brought into contact with an alkali for a long period of time, their mechanical strength is lowered, and problems of deteriorated hand and coloring irregularity are offered. It is therefore essential to minutely control the conditions of the application of the alkali. Any measure for solving these problems has not been yet disclosed to date. Detailed investigations have also been made on the influence of heating means. More specifically, fixing conditions of 80°C to 102°C or so do not offer a very serious problem. If a fixing temperature is preset to conditions exceeding 103°C to enhance dyeing efficiency, however, silk fibers offers a problem of their own that the color yield is rapidly lowered unlike the case of other reactive dye-dyeable fibers typified by cellulose fibers. Against this problem of lowered color yield, a measure on cellulose fiber that an antireductant is added together with an alkaline substance with a view toward preventing coloring ability from lowering due to the reductive decomposition of dyes upon steaming is disclosed in Japanese Patent Application Laid-Open No. 62-299588. The cause of deteriorating the coloring ability in the silk fibers is different from that in the cellulose fibers and considered to be attributable to hydrolysis attendant upon change in coloring temperature rather than the reductive decomposition of dyes. It is therefore necessary to propose a measure for overcoming this problem by an absolutely different idea. As described above, means capable of satisfying the above individual performance characteristics to some extent have been able to be found in the prior art. However, there have not been yet known under the circumstances any ink-jet printing cloth composed mainly of silk and any ink-jet printing process, which can satisfy all the above-mentioned performance characteristics at the same time, solve such a series of problems and provide the highest-quality image. EP-A-0,558,914 discloses an ink-jet textile printing process wherein a silk cloth is pre-treated to contain from 0.01 to 5% by weight of an alkaline material. Such a pre-treated cloth may be used for printing thereon with an ink-jet printing ink. JP-A-62-299588 discloses an ink-jet printing cloth composed of cellulosic fibres which is impregnated with 0 to 10% by weight of an alkaline substance. Such a cloth may be used for ink-jet printing with an ink containing a reactive dye. EP-A-0,621,367, a document according to Art. 54(3) EPC, discloses an ink-jet printing process, wherein a pre-treatment of the cloth with an alkaline substance is conducted so that the cloth contains 0.01 to 5% by weight of an alkaline substance. Such a pre-treated cloth may be used for printing thereon with an ink-jet printing ink. SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an ink-jet printing process and a thus produced ink-jet printing cloth, which satisfies, at the same time, the above-described general problems involved in the conventional ink-jet printing cloths, i.e., a problem of image that a bright print free of ink bleeding and high in color depth is provided, a problem of quality that coloring ability in high-temperature fixing is stable, a problem of cost that the color yield of ink is good, a problem of operating characteristics or properties such as storage stability and feedability in apparatus of treated cloth, etc. The above object can be achieved by the present invention described below. According to the present invention, there is also provided a process for producing an ink-jet printing cloth suitable fordyeing with inks containing a reactive dye and is composed mainly of silk fibers, wherein the cloth contains an alkaline substance in an amount not less than 0.8 % by weight based on the dry weight of the cloth, and the surface pH of the cloth is adjusted to 8.2 or lower, the process being defined in claim 1. According to the present invention, there is further provided an ink-jet printing process comprising applying inks containing a reactive dye to the above cloth, the process being defined in claim 3. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a longitudinal cross-sectional view of a head of an ink-jet recording apparatus. Fig. 2 is a transverse cross-sectional view of the head of the ink-jet recording apparatus. Fig. 3 is a perspective view of the appearance of a multi-head which is an array of such heads as shown in Fig. 1. Fig. 4 is a perspective view of an illustrative ink-jet recording apparatus. DESCRIPTION OF THE PREFERRED EMBODIMENTS An ink-jet printing process, in which an ink markedly low in viscosity compared with the conventional printing pastes is used, and an image is formed by dot expression of this ink, has extremely many limitations on pretreatment conditions of cloth compared with other textile printing processes. That influence is particularly great in the case where a cloth composed mainly of silk fibers is dyed with inks containing a reactive dye. In the case of the dyeing with inks containing a reactive dye, an alkaline agent is an essential component as a catalyst. However, the silk fibers undergo a chemical change by the alkaline agent. Therefore, they may bring about changes in properties with time after their treatment according to the conditions of the treatment. It is thus necessary to strictly limit the conditions of the pretreatment. Besides, if a steaming treatment is conducted at such a high temperature as exceeds 103°C, a ratio of a reaction rate between the reactive dye and the silk fibers to a rate of hydrolysis of the dye markedly changes, and so a proportion of hydrolysis rapidly increases. For this reason, color yield is lowered to a great extent and stability to coloring is deteriorated. This phenomenon is considered as a phenomenon characteristic of the silk fibers because it is extremely rare in cellulose fibers compared with the silk fibers, which thus causes no problem in actual use. The present inventors have carried out improvement in ink-jet printing cloths composed mainly of silk fibers with a view toward allowing them to satisfy the various performance characteristics as described above at the same time. As a result, it has been found that when the absolute weight of an alkaline substance based on the cloth is controlled to a certain range, and the surface pH of the cloth is controlled to a specific range with an organic acid, the above characteristics or properties are improved to a marked extent, thus leading to completion of the present invention. The present invention will hereinafter be described in more detail by the following preferred embodiments. The term "printing cloth" as used herein means a woven fabric, nonwoven fabric, knitted fabric, felted fabric or the like composed principally of silk yarn. It goes without saying that the cloth is preferably formed of silk fibers alone. However, blended woven fabrics or nonwoven fabrics of silk fibers and one or more other materials may also be used as ink-jet printing cloths in the present invention so far as they contain silk fibers at a blending ratio of at least 70 %, preferably at least 80 %. With respect to the silk cloth mainly constituting the ink-jet printing cloth, the average thickness of the fibers is controlled to 2.2 to 3.5 deniers, preferably 2.5 to 3.3 deniers. The average thickness of the silk yarn formed of the silk fibers is controlled to 14 to 147 deniers, preferably 14 to 126 deniers, more preferably 14 to 105 deniers. The silk yarn may preferably be formed into a cloth by any conventional method to use it in the present invention. With respect to the measurement of the average thickness of the fibers, their Micronaire fineness is determined by the Micronaire method, and the value is converted into the weight per 9000 m to express it in terms of a denier unit. If average thicknesses of the silk fibers and silk yarn are thinner than the lower limits or thicker than the upper limits of the above described ranges, the entanglement of the silk fibers may become improper, thus resulting in a cloth poor in dyeing properties, color yield, resistance to bleeding and fixing ability as to inks, and its feedability in apparatus. Examples of the alkaline substances used in the present invention include alkali metal carbonates and bicarbonates such as sodium carbonate, potassium carbonate and sodium bicarbonate. Sodium carbonate and sodium bicarbonate are particularly preferred alkaline substances. The object of the present invention is achieved when the alkaline substance is applied in an amount not less than 0.8 % by weight based on the dry weight of the cloth, and the surface pH of the cloth is adjusted to a range of from 6 to 8.2. In this case, the surface pH is more preferably adjusted to 6 to 8, most preferably 6.5 to 8. In order to achieve the above surface pH, an organic acid is used, thereby adjusting the pH of the alkaline substance. Although any organic acid may be used in this case, it is preferable to use any of the below organic acids, or a salt thereof (according to the pH intended). It is more preferable to use an organic carboxylic acid, organic sulfonic acid or a salt thereof. The adjustment of the pH may be performed either by adjusting the pH of a pretreatment solution containing the alkaline substance in advance or by subjecting the cloth after the pretreatment with the alkaline substance to an after-treatment with the acid so as to adjust the surface pH. The term "surface pH" as used herein means a value measured by the same means as "Surface pH Measurement of Paper" prescribed by Japan Technical Association of the Pulp and Paper Industry. A moisture regain suitable for the ink-jet printing cloths according to the present invention is within a range of from 17 to 112 %, preferably from 18 to 92 %, more preferably from 19 to 72 %. If the moisture regain is lower than 17 %, disadvantages may arise from the viewpoints of coloring ability and color yield. On the other hand, any moisture regain exceeding 112 % tends to offer problems from the viewpoints of feedability and particularly, resistance to bleeding. Incidentally, the official moisture regain of raw silk is 12 %. The measurement of the moisture regain in the cloth was conducted by reference to JIS L 1019. More specifically, 100 g of a sample was precisely weighed and placed in an oven at 105 ± 2°C, thereby drying the sample to a constant weight. Thereafter, the cloth was washed with water and then dried again to a constant weight to measure the weight of fibers alone after the drying. The moisture regain was then determined in accordance with the following equation: Moisture regain (%) = ((W - W')/W''} x 100 wherein W is a weight before the drying, W' is a weight after the drying, and W'' is a weight of fibers after the water washing and drying. The ink-jet printing cloths according to the present invention may be subjected to any pretreatment routinely used as needed. In particular, cloths containing at least one substance selected from the group consisting of water-soluble metal salts, water-soluble polymers, urea and thiourea in an amount of 0.01 to 20 % by weight may be more preferred in some cases. Examples of the water-soluble polymers include natural water-soluble polymers such as starches from corn, wheat and the like, cellulosic substances such as carboxymethylcellulose, methylcellulose and hydroxyethylcellulose, polysaccharides such as sodium alginate, gum arabic, locust bean gum, tragacanth gum, guar gum and tamarind seed, proteins such as gelatin and casein, tannin and derivatives thereof, and lignin and derivatives thereof. Examples of synthetic polymers include polyvinyl alcohol type compounds, polyethylene oxide type compounds, water-soluble acrylic polymers, water-soluble maleic anhydride polymers and the like. Of these, the polysaccharide polymers and cellulosic polymers are preferred. Examples of the water-soluble metal salts include compounds such as halides of alkali metals and alkaline earth metals, which form typical ionic crystals. As representative examples of such compounds, may be mentioned NaCl, Na 2 SO 4 and KCl for alkali metals, and CaCl 2 and MgCl 2 for alkaline earth metals. Of these, salts of Na, K and Ca are preferred. As inks used for the ink-jet printing cloths according to the present invention, it is essential to use ink-jet printing inks comprising a reactive dye and an aqueous liquid medium. Among others, substitution reaction type dyes are reactive dyes which can manifest the effects to a marked extent in the process of the present invention. In particular, reactive dyes having a monochlorotriazine group are effective. Specific examples of these dyes include those typified by C.I. Reactive Yellow 2, 85 and 95; C.I. Reactive Red 24, 31, 218 and 226; C.I. Reactive Blue 13, 15, 49, 71 and 72; and C.I. Reactive Orange 5 and 13. These dyes may be contained in an ink either singly or in any combination with dyes of the same or different hues. The total amount of the dyes to be used is generally within a range of from 0.5 to 30 % by weight, preferably from 1 to 25 % by weight, more preferably from 2 to 20 % by weight based on the total weight of the ink. It is also preferred embodiments to add a chloride ion and/or a sulfate ion to the ink used in the process of the present invention in a proportion of about 10 to 20,000 ppm based on the reactive dye(s) contained in the ink, and to add at least one substance selected from the group consisting of silicon, iron, nickel and zinc to the ink in a proportion of about 0.1 to 30 ppm in total. As a result, when ink-jet printing is conducted with such inks on the ink-jet printing cloth according to the present invention, a bright print high in color yield, free of any bleeding and higher in color depth can be obtained. Further, calcium and/or magnesium may preferably be contained in the ink in a total amount ranging from 0.1 to 30 ppm, preferably from 0.2 to 20 ppm, more preferably from 0.3 to 10 ppm in combination with the metal salts mentioned above because the color yield can be more enhanced. Water which is a principal component of the liquid medium making up the ink used in the ink-jet printing process of the present invention is used within a range of from 30 to 90 % by weight, preferably from 40 to 90 % by weight, more preferably from 50 to 85 % by weight based on the total weight of the ink. The above components are principal components of the ink-jet printing inks used in the process of the present invention. However, general organic solvents may also be used in combination with water as other components of the liquid medium for the inks. Examples thereof include ketones and keto-alcohols such as acetone and diacetone alcohol; ethers such as tetrahydrofuran and dioxane; addition polymers of oxyethylene or oxypropylene with diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, polyethylene glycol, polypropylene glycol and the like; alkylene glycols the alkylene moiety of which has 2 to 6 carbon atoms, such as ethylene glycol, propylene glycol, trimethylene glycol, butylene glycol and hexylene glycol; thiodiglycol; triols such as 1,2,6-hexanetriol and glycerol; lower alkyl ethers of polyhydric alcohols, such as ethylene glycol monomethyl (or monoethyl) ether, diethylene glycol monomethyl (or monoethyl) ether and triethylene glycol monomethyl (or monoethyl) ether; lower dialkyl ethers of polyhydric alcohols, such as triethylene glycol dimethyl (or diethyl) ether and tetraethylene glycol dimethyl (or diethyl) ether; sulfolane; N-methyl-2-pyrrolidone; and 1,3-dimethyl-2-imidazolidinone. The content of the water-soluble organic solvent as described above is generally within a range of from 3 to 60 % by weight, preferably from 5 to 50 % by weight based on the total weight of the ink. The liquid medium components as described above may be used either singly or in any combination thereof if used in combination with water. However, the most preferred composition of the liquid medium is that comprising at least one polyhydric alcohol as such a solvent. Among others, a single solvent of thiodiglycol or a mixed solvent system of diethylene glycol and thiodiglycol is particularly preferred. Although the principal components of the inks used in the process of the present invention are as described above, a variety of other additives such as a dispersant, a surfactant, a viscosity modifier, a surface tension modifier and an optical whitening agent may be added to the inks as needed. Examples of such additives may include viscosity modifiers such as polyvinyl alcohol and water-soluble resins; various anionic or nonionic surfactants; surface tension modifiers such as diethanolamine and triethanolamine; pH adjustors comprising a buffer solution; mildewproofing agents; and the like. The ink-jet printing process of the present invention is a process in which the printing inks as described above are used to conduct textile printing on the ink-jet printing cloth according to the present invention. An ink-jet printing system used may be any conventionally-known ink-jet recording system. However, the method described in Japanese Patent Application Laid-Open No. 54-59936, i.e., a system in which thermal energy is applied to an ink so as to undergo rapid volume change, and the ink is ejected from an orifice by action force caused by this change of state is the most effective method. When printing is conducted on the ink-jet printing cloth according to the present invention by such a system, stable printing is feasible. As conditions under which a print particularly high in effect can be obtained, it is preferred that an ejected ink droplet be within a range of from 20 to 200 pl, a shot-in ink quantity be within a range of from 4 to 40 nl/mm 2 , and an adhered amount of dye be within a range of from 0.025 to 1 mg/cm 2 . As an illustrative example of an apparatus, which is suitable for use in conducting textile printing using the ink-jet printing cloths according to the present invention, may be mentioned an apparatus in which thermal energy corresponding to recording signals is applied to an ink within a recording head, and ink droplets are generated in accordance with the thermal energy. Examples of the construction of an head, which is a main component of such an apparatus, are illustrated in Figs. 1, 2 and 3. A head 13 is formed by bonding a glass, ceramic or plastic plate or the like having a groove 14 through which an ink is passed, to a heating head 15, which is used for thermal recording (the drawing shows a head to which, however, is not limited). The heating head 15 is composed of a protective film 16 made of silicon oxide or the like, aluminum electrodes 17-1 and 17-2, a heating resistor layer 18 made of nichrome or the like, a heat accumulating layer 19, and a substrate 20 made of alumina or the like having a good heat radiating property. An ink 21 comes up to an ejection orifice (a minute opening) 22 and forms a meniscus 23 owing to a pressure P. Now, upon application of electric signals to the electrodes 17-1, 17-2, the heating head 15 rapidly generates heat at the region shown by n to form bubbles in the ink 21 which is in contact with this region. The meniscus 23 of the ink is projected by the action of the pressure thus produced, and the ink 21 is ejected from the orifice 22 to a cloth 25 of the present invention composed mainly of silk fibers in the form of recording droplets 24. Fig. 3 illustrates an appearance of a multi-head composed of an array of a number of heads as shown in Fig. 1. The multi-head is formed by closely bonding a glass plate 27 having a number of channels 26 to a heating head 28 similar to the head as illustrated in Fig. 1. Incidentally, Fig. 1 is a cross-sectional view of the head 13 taken along the flow path of the ink, and Fig. 2 is a cross-sectional view taken along line 2-2 in Fig. 1. Fig. 4 illustrates an example of an ink-jet recording apparatus in which such a head has been incorporated. In Fig. 4, reference numeral 61 designates a blade serving as a wiping member, one end of which is a stationary end held by a blade-holding member to form a cantilever. The blade 61 is provided at the position adjacent to the region in which a recording head operates, and in this embodiment, is held in such a form that it protrudes to the course through which the recording head is moved. Reference numeral 62 indicates a cap, which is provided at the home position adjacent to the blade 61, and is so constituted that it moves in the direction perpendicular to the direction in which the recording head is moved and comes into contact with the face of ejection openings to cap it. Reference numeral 63 denotes an absorbing member provided adjoiningly to the blade 61 and, similar to the blade 61, held in such a form that it protrudes to the course through which the recording head is moved. The above-described blade 61, cap 62 and absorbing member 63 constitute an ejection-recovery portion 64, where the blade 61 and absorbing member 63 remove water, dust and/or the like from the face of the ink-ejecting openings. Reference numeral 65 designates the recording head having an ejection-energy-generating means and serving to eject the ink onto the silk fiber-containing cloth set in an opposing relation with the ejection opening face provided with ejection openings to conduct recording. Reference numeral 66 indicates a carriage on which the recording head 65 is mounted so that the recording head 65 can be moved. The carriage 66 is slidably interlocked with a guide rod 67 and is connected (not illustrated) at its part to a belt 69 driven by a motor 68. Thus, the carriage 66 can be moved along the guide rod 67 and hence, the recording head 65 can be moved from a recording region to a region adjacent thereto. Reference numerals 51 and 52 denote a cloth feeding part from which the cloths of the present invention composed mainly of silk fibers are separately inserted, and cloth feed rollers driven by a motor (not illustrated), respectively. With such construction, the cloth according to the present invention is fed to the position opposite to the ejection opening face of the recording head, and discharged from a cloth discharge section provided with cloth discharge rollers 53 with the progress of recording. In the above constitution, the cap 62 in the head recovery portion 64 is receded from the moving course of the recording head 65 when the recording head 65 is returned to its home position, for example, after completion of recording, and the blade 61 remains protruded to the moving course. As a result, the ejection opening face of the recording head 65 is wiped. When the cap 62 comes into contact with the ejection opening face of the recording head 65 to cap it, the cap 62 is moved so as to protrude to the moving course of the recording head. When the recording head 65 is moved from its home position to the position at which recording is started, the cap 62 and the blade 61 are at the same positions as the positions upon the wiping as described above. As a result, the ejection opening face of the recording head 65 is also wiped at the time of this movement. The above movement of the recording head to its home position is made not only when the recording is completed or the recording head is recovered for ejection, but also when the recording head is moved between recording regions for the purpose of recording, during which it is moved to the home position adjacent to each recording region at given intervals, where the ejection opening face is wiped in accordance with this movement. The printing inks applied onto the ink-jet printing cloth of this invention in accordance with the process of the present invention in the above-described manner only adhere to the cloth in this state. Accordingly, it is preferable to subsequently subject the cloth to a process for reactively fixing the dyes in the inks to the fibers and a process for removing unfixed dyes. A steaming process is a fixing process by which the effects of the present invention are particularly markedly exhibited. Among others, a high-temperature printing process using an HT steamer is preferred. Conditions of at least 103°C, or at least 105°C according to dyes to be used are temperature conditions which can have a marked effect on stability to coloring compared with the conventional cloths. The washing may be conducted in accordance with any conventionally known method. The present invention will hereinafter be described more specifically by the following Examples and Comparative Examples. Incidentally, all designations of "part" or "parts" and "%" as will be used in the following examples mean part or parts by weight and % by weight unless expressly noted. Preparation of Ink (A): Reactive dye (C.I. Reactive Yellow 95) 10 parts Thiodiglycol 24 parts Diethylene glycol 11 parts Potassium chloride 0.004 part Sodium sulfate 0.002 part Sodium metasilicate 0.001 part Iron chloride 0.0005 part Water 55 parts. All the above components were mixed, and the liquid mixture was adjusted to pH 8.4 with sodium hydroxide. After stirring the mixture for 2 hours, it was filtered through a "Fluoropore Filter FP-100" (trade name; product of Sumitomo Electric Industries, Ltd.), thereby obtaining Ink-Jet Printing Ink (A). Preparation of Ink (B): Reactive dye (C.I. Reactive Red 266) 10 parts Thiodiglycol 15 parts Diethylene glycol 10 parts Tetraethylene glycol dimethyl ether 5 parts Potassium chloride 0.04 part Sodium sulfate 0.01 part Sodium metasilicate 0.001 part Iron chloride 0.0005 part Nickel chloride 0.0002 part Water 60 parts. All the above components were mixed, and the liquid mixture was adjusted to pH 7.9 with sodium hydroxide. After stirring the mixture for 2 hours, it was filtered through a "Fluoropore Filter FP-100" (trade name; product of Sumitomo Electric Industries, Ltd.), thereby obtaining Ink-Jet Printing Ink (B). Preparation of Ink (C): Reactive dye (C.I. Reactive Blue 15) 13 parts Thiodiglycol 23 parts Triethylene glycol monomethyl ether 6 parts Potassium chloride 0.05 part Sodium metasilicate 0.001 part Iron chloride 0.0005 part zinc chloride 0.0003 part Water 58 parts. All the above components were mixed, and the liquid mixture was adjusted to pH 8.3 with sodium hydroxide. After stirring the mixture for 2 hours, it was filtered through a "Fluoropore Filter FP-100" (trade name; product of Sumitomo Electric Industries, Ltd.), thereby obtaining Ink-Jet Printing Ink (C). Preparation of Ink (D): Reactive dye (C.I. Reactive Brown 11) 2 parts Reactive dye (C.I. Reactive Orange 12) 1.5 parts Reactive dye (C.I. Reactive Black 39) 6.5 parts Thiodiglycol 23 parts Diethylene glycol 5 parts Isopropyl alcohol 3 parts Potassium sulfate 0.01 part Sodium metasilicate 0.001 part Iron sulfate 0.0005 part Nickel sulfate 0.0003 part Zinc sulfate 0.0003 part Water 59 parts. All the above components were mixed, and the liquid mixture was adjusted to pH 8.2 with sodium hydroxide. After stirring the mixture for 2 hours, it was filtered through a "Fluoropore Filter FP-100" (trade name; product of Sumitomo Electric Industries, Ltd.), thereby obtaining Ink-Jet Printing Ink (D). Reference Example 1 : A 100 % silk woven fabric formed of silk yarn having an average thickness of 22 deniers, which was composed of silk fibers having an average thickness of 3 deniers, was immersed in an aqueous solution containing 1 % of sodium hydrogencarbonate, 10 % of urea and 1 % of sodium alginate, squeezed to a pickup of 60 % and then dried to adjust the moisture regain of the fabric to 20 %. Ink-Jet Printing Inks (A through D) obtained in the above-described manner were charged in a "Color Bubble Jet Printer BJC-820J" (trade name, manufactured by Canon Inc.) to print solid print samples of 2 x 10 cm on the thus-pretreated woven fabric under conditions of a shot-in ink quantity of 16 nl/mm 2 . The solid print samples of each color were fixed by steaming treatments for 8 minutes at 102°C, 103°C, 105°C and 110°C, respectively. Thereafter, these print samples were washed to evaluate the resulting prints in color depth. The results are shown in Table 1. At each steaming temperature, all the prints of the individual colors were good in resistance to bleeding and brightness. Upon elapsed time of 1 month after the treatment of the fabric, the same test was conducted. As a result, the storage stability of the fabric was also good. Reference Example 2 : The same woven fabric as that used in Reference Example 1 was immersed in an aqueous solution containing 0.1 % of sodium hydroxide, 10 % of urea and 1 % of sodium alginate, squeezed to a pickup of 60 % and then dried to adjust the moisture regain of the fabric to 20 %. Using this woven fabric, printing, fixing and washing were conducted in the same manner as in Reference Example 1 to evaluate the resulting prints in color depth. The results are shown in Table 1. At each steaming temperature, all the prints of the individual colors were good in resistance to bleeding and brightness. Reference Example 3 : A 100 % silk woven fabric formed of silk yarn having an average thickness of 30 deniers, which was composed of silk fibers having an average thickness of 2.7 deniers, was immersed in an aqueous solution containing 0.5 % of sodium carbonate, 10 % of urea and 1 % of sodium alginate, squeezed to a pickup of 60 % and then dried to adjust the moisture regain of the fabric to 20 %. Using this woven fabric, printing, fixing and washing were conducted in the same manner as in Reference Example 1 to evaluate the resulting prints in color depth. The results are shown in Table 1. At each steaming temperature, all the prints of the individual colors were good in resistance to bleeding and brightness. Example 4 : A 100 % silk woven fabric formed of silk yarn having an average thickness of 22 deniers, which was composed of silk fibers having an average thickness of 3 deniers, was immersed in an aqueous solution containing 2 % of sodium hydrogencarbonate, 10 % of urea and 1 % of sodium alginate (the pH of which was adjusted to 8.1 with sodium m-nitrobenzenesulfonate), squeezed to a pickup of 60 % and then dried to adjust the moisture regain of the fabric to 20 %. The surface pH of this fabric was measured and found to be 8.0. Using this woven fabric, printing, fixing and washing were conducted in the same manner as in Reference Example 1 to evaluate the resulting prints in color depth. The results are shown in Table 1. At each steaming temperature, all the prints of the individual colors were good in resistance to bleeding and brightness. Example 5 : The same woven fabric as that used in Example 4 was immersed in an aqueous solution containing 2 % of sodium carbonate, 10 % of urea and 1 % of sodium alginate (the pH of which was adjusted to 7.0 with acetic acid), squeezed to a pickup of 60 % and then dried to adjust the moisture regain of the fabric to 20 %. The surface pH of this fabric was measured and found to be 6.8. Using this woven fabric, printing, fixing and washing were conducted in the same manner as in Reference Example 1 to evaluate the resulting prints in color depth. The results are shown in Table 1. At each steaming temperature, all the prints of the individual colors were good in resistance to bleeding and brightness. Example 6 : A 100 % silk woven fabric formed of silk yarn having an average thickness of 30 deniers, which was composed of silk fibers having an average thickness of 2.7 deniers, was immersed in an aqueous solution containing 3 % of sodium carbonate, 10 % of urea and 1 % of sodium alginate (the pH of which was adjusted to 7.5 with sodium m-nitrobenzenesulfonate), squeezed to a pickup of 60 % and then dried to adjust the moisture regain of the fabric to 20 %. The surface pH of this fabric was measured and found to be 7.5. Using this woven fabric, printing, fixing and washing were conducted in the same manner as in Reference Example 1 to evaluate the resulting prints in color depth. The results are shown in Table 1. At each steaming temperature, all the prints of the individual colors were good in resistance to bleeding and brightness. Example 7: The same woven fabric as that used in Example 6 was immersed in an aqueous solution containing 5 % of sodium hydrogencarbonate, 10 % of urea and 1 % of sodium alginate (the pH of which was adjusted to 6.0 with acetic acid), squeezed to a pickup of 60 % and then dried to adjust the moisture regain of the fabric to 20 %. The surface pH of this fabric was measured and found to be 6.1. Using this woven fabric, printing, fixing and washing were conducted in the same manner as in Reference Example 1 to evaluate the resulting prints in color depth. The results are shown in Table 1. At each steaming temperature, all the prints of the individual colors were good in resistance to bleeding and brightness. Comparative Example 1 : The same woven fabric as that used in Reference Example 1 was immersed in an aqueous solution containing 2.5 % of sodium hydrogencarbonate, 10 % of urea and 1 % of sodium alginate, squeezed to a pickup of 60 % and then dried to adjust the moisture regain of the fabric to 20 %. The surface pH of this fabric was measured and found to be 9.2. Using this woven fabric, printing, fixing and washing were conducted in the same manner as in Reference Example 1 to evaluate the resulting prints in color depth. As shown in Table 1, the results revealed that this fabric was poor in coloring ability upon high-temperature steaming as to some of the inks compared with the fabric of Reference Example 1. Comparative Example 2 : The same woven fabric as that used in Reference Example 1 was immersed in an aqueous solution containing 1.5 % of sodium carbonate, 10 % of urea and 1 % of sodium alginate, squeezed to a pickup of 60 % and then dried to adjust the moisture regain of the fabric to 20 %. The surface pH of this fabric was measured and found to be 10.0 Using this woven fabric, printing, fixing and washing were conducted in the same manner as in Reference Example 1 to evaluate the resulting prints in color depth. As shown in Table 1, the results revealed that this fabric was poor in coloring ability upon high-temperature steaming as to all the inks compared with the fabric of Reference Example 1. Comparative Example 3 : The same woven fabric as that used in Reference Example 1 was immersed in an aqueous solution containing 0.01 % of sodium carbonate, 10 % of urea and 1 % of sodium alginate, squeezed to a pickup of 60 % and then dried to adjust the moisture regain of the fabric to 20 %. Using this woven fabric, printing, fixing and washing were conducted in the same manner as in Reference Example 1 to evaluate the resulting prints in color depth. As a result, it was revealed that dyeing itself was insufficient, and the color depth of the prints was hence lower. As shown in Table 1, the relative color depth was also poor. Comparative Example 4: The same woven fabric as that used in Example 4 was immersed in an aqueous solution containing 2 % of sodium hydrogencarbonate, 10 % of urea and 1 % of sodium alginate (the pH of which was adjusted to 8.5 with sodium m-nitrobenzenesulfonate), squeezed to a pickup of 60 % and then dried to adjust the moisture regain of the fabric to 20 %. The surface pH of this fabric was measured and found to be 8.4. Using this woven fabric, printing, fixing and washing were conducted in the same manner as in Reference Example 1 to evaluate the resulting prints in color depth. As shown in Table 1, the results revealed that this fabric was poor in coloring ability upon high-temperature steaming as to some of the inks compared with the fabric of Reference Example 1. Comparative Example 5 : The same woven fabric as that used in Example 4 was immersed in an aqueous solution containing 2 % of sodium carbonate, 10 % of urea and 1 % of sodium alginate (the pH of which was not adjusted), squeezed to a pickup of 60 % and then dried to adjust the moisture regain of the fabric to 20 %. The surface pH of this fabric was measured and found to be 9.0. Using this woven fabric, printing, fixing and washing were conducted in the same manner as in Reference Example 1 to evaluate the resulting prints in color depth. As shown in Table 1, the results revealed that this fabric was poor in coloring ability upon high-temperature steaming as to all the inks compared with the fabric of Reference Example 1. Comparative Example 6 : The same woven fabric as that used in Example 6 was immersed in an aqueous solution containing 3 % of sodium carbonate, 10 % of urea and 1 % of sodium alginate (the pH of which was adjusted to 9 with acetic acid), squeezed to a pickup of 60 % and then dried to adjust the moisture regain of the fabric to 20 %. The surface pH of this fabric was measured and found to be 9.1. Using this woven fabric, printing, fixing and washing were conducted in the same manner as in Reference Example 1 to evaluate the resulting prints in color depth. As shown in Table 1, the results revealed that this fabric was poor in coloring ability upon high-temperature steaming as to all the inks compared with the fabric of Reference Example 1. Evaluated item Example Comparative Example 1 2 3 4 5 6 7 1 2 3 4 5 6 Color depth at 103°C A A A A A A A A B B A B B Color depth at 105°C A A A A A A A B C B B C B Color depth at 110°C A A A A A A A C C B C C C wherein K/S value = (1 - R) 2 /2R (R: reflectance at a maximum absorption wavelength). A: Relative color depth was at least 0.95 in all the colors; B: Relative color depth was reduced to 0.94 down to 0.5 in some of the inks; C: Relative color depth was reduced to 0.49 or lower in some of the inks. According to the textile printing cloths of the present invention, as described above, there can be solved the problem of image that a bright print free of ink bleeding and high in color depth is provided, the problem of quality that coloring ability in high-temperature fixing is stable, the problem of cost that the color yield of ink is good, the problem of operating characteristics or properties such as storage stability and feedability in apparatus of treated cloth, etc. at the same time. While the present invention has been described with respect to the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments.

Claims: A process for producing an ink-jet printing cloth suitable for dyeing with an ink comprising a reactive dye, the cloth mainly composed of silk fibers, comprising the steps of: (i) providing an alkali solution containing an alkaline substance selected from the group consisting of alkali metal carbonates and bicarbonates; (ii) applying the alkali solution to a cloth composed of silk fibers such that the cloth contains the alkaline substance in an amount of not less than 0.8% by weight based on the dry weight of the cloth and the process further comprises subjecting the cloth resulting from the step (ii) to measured by the same means as (iii) a treatment with an organic acid so that the surface pH of the cloth "Surface pH Measurement of Paper and Paperboard" prescribed by Japan Technical Association of the Pulp and Paper Industry ranges from 6 to 8.2. The process according to claim 1, wherein the step (iii) includes adding the organic acid to the alkaline solution which is to be used in the step (i) so that the cloth resulting from the step (ii) has a surface pH of 6 to 8.2. A process for preparing a printed cloth comprising the steps of producing an ink-jet printing cloth according to claim 1, further comprising: (iv) applying an ink containing a reactive dye to the cloth resulting from the step (iii); (v) heating the cloth resulting from the step (iv) at a temperature of 103°C or higher; and (vi) washing the cloth resulting from the step (v). The process according to any one of claims 1 to 3, wherein the cloth is formed of silk yarn having an average thickness of 14 to 147 deniers, which is composed of silk fibers having an average thickness of 2.2 to 3.5 deniers. The process according to any one of claims 1 to 4, wherein the moisture regain of the cloth is in a range of from 17 to 112% by weight based on the dry weight of the cloth. The process according to any one of claims 1 to 5, wherein the pH of the surface of the cloth is in a range of from 6 to 8. The process according to claim 6, wherein the pH of the surface of the cloth is in a range of from 6.5 to 8. The process according to any one of claims 3 to 7, wherein the ink contains reactive dyes in an amount of 0.5 to 30% by weight of the ink.

Inventors: HARUTA MASAHIRO, KOIKE SHOJI, MIURA YASUSHI, MIYASHITA YOSHIKO, SHIROTA KOROMO, SUZUKI MARIKO, TAKAIDE AYA, YAMAMOTO TOMOYA, HARUTA, MASAHIRO, KOIKE, SHOJI, MIURA, YASUSHI, MIYASHITA, YOSHIKO, SHIROTA, KOROMO, SUZUKI, MARIKO, TAKAIDE, AYA, YAMAMOTO, TOMOYA, HARUTA, MASAHIRO, C/O CANON K.K., KOIKE, SHOJI, C/O CANON K.K., MIURA, YASUSHI, C/O CANON K.K., MIYASHITA, YOSHIKO, C/O CANON K.K., SHIROTA, KOROMO, C/O CANON K.K., SUZUKI, MARIKO C/O CANON K.K., TAKAIDE, AYA, C/O CANON K.K., YAMAMOTO, TOMOYA, C/O CANON K.K.
Applicants: CANON KK, CANON KABUSHIKI KAISHA
Application year: 1995
Main classification: D06P1
IPC codes: D06P1, B41J2, D06P5, D06P3