Method of photocatalytic white discharge printing for achieving patterns on textiles

Abstract

A method for photocatalytic white discharge printing for achieving patterns on textiles includes closely integrating substrates with patterned printing plates or fixing patterned printing plates on one or both sides of a substrate, placing them in a reactor equipped with a light source and containing the photocatalytic white discharging formulation. The method has the characteristics of a simple process, short processing, easy controlling and wide adaptability. The process eliminates the need for printing plates and expensive printing apparatus used in complicated conventional printing methods. Additionally, the photocatalytic solution can be reused which avoids generous application of chemical agents and waste discharges that are present in conventional printing methods. The method is beneficial for cutting costs, saving energy, reducing emissions and has cleaner production.

Claims

1. A method of photocatalytic white discharge printing for achieving patterns on textiles consisting of the following steps: a) dye the textiles with dyes to obtain dyed textiles; b) form hollow-outs decorative patterns according to required patterns with materials which are opaque and thin or thick films plates by a physical or chemical method, so patterned printing plates are obtained; c) closely integrate the patterned printing plates and the dyed textiles or fix the patterned printing plates on one or both sides of the dyed textiles, then put the dyed textiles in a reactor equipped with a light source and occupied by a photocatalytic white discharge formulation, pump air or oxygen into the reactor, open the light source, directly expose the dyed textiles through the hollow-outs in the patterned printing plates, and treat the dyed textiles for about 1-90 minutes at temperatures ranging from 5° C. to 70° C., wherein the photocatalytic white discharge formulation contains potassium persulfate at a concentration of 0.10 g/L-10.00 g/L and the formulation has a pH value of 2-12; d) wash and dry the dyed textiles removed from the photocatalytic white discharging bath at room temperature.

2. A method of photocatalytic white discharge printing for achieving patterns on textiles as recited in claim 1, wherein the dyes are one of C.I. Reactive Red 2, C.I. Reactive Red 195 and C.I. Reactive Blue 222, or any combination thereof.

3. A method of photocatalytic white discharge printing for achieving patterns on textiles as recited in claim 1, wherein the patterned printing plates are produced by mechanical or manual engraving, or laser etching.

4. A method of photocatalytic white discharge printing for achieving patterns on textiles as recited in claim 1, wherein the light source is ultraviolet or visible light, whose power is 5˜500 w.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 of the drawings is the schematic of a reactor provided by present invention, and it is used for achieving patterns on textiles adopting the method of white discharge batch printing.

(2) FIG. 2 of the drawings is the whiteness of cottons discharged by different kinds of discharging agents as example 1 recited.

(3) FIG. 3 of the drawings presents the effect of white discharge printing process as example 2 recited.

(4) FIG. 4 of the drawings illustrates the effect of white discharge printing as example 3 recited.

(5) FIG. 5 of the drawings illustrates the effect of white discharge printing as example 4 recited.

(6) FIG. 6 of the drawings illustrates the effect of white discharge printing with cottons that combination dyed as example 5 recited.

(7) In the FIG. 1: 1. Power supply wiring (omitting the power); 2. Batch process unit; 3. Tube of quartz; 4. Low-pressure mercury violet lamp; 5. Dyed textiles; 6. Device of Aeration; 7. Patterned printing plate.

Concrete Instance

(8) Combined with the appended drawings and specific examples, make a further illustration for this invention, and the concrete chemicals involved are as follows:

(9) Ground shade dyes: Reactive Red X-3B, Reactive Red M-3BE and Reactive Blue222BF are commonly commercial products.

(10) Photocatalytic white discharging agent: potassium persulfate (K.sub.2S.sub.2O.sub.8), hydrogen peroxide (H.sub.2O.sub.2), sodium sulfite (Na.sub.2SO.sub.3), sodium hyposulfite (Na.sub.2S.sub.2O.sub.3), sodium hydrosulfite (Na.sub.2S.sub.2O.sub.4), nano TiO.sub.2 and doping nano TiO.sub.2 are also commonly commercial products.

EXAMPLE 1

(11) A method of photocatalytic white discharge printing for achieving patterns on textiles provided by this example includes the following steps:

(12) 1. Textiles are dyed with selected dyes by conventional dyeing method. The substrate is cotton fabric (dimension of 8 cm×20 cm), and the processing conditions are as common as: Reactive Red X-3B (dosage of 3.0% o.m.f), sodium sulfate (24.0 g/L), sodium carbonate (15.0 g/L), pH value of fixing formulation is 10.5, and the liquor ratio is 1 to 30; after 15 minutes dyeing at room temperature, salt is added to promote dyeing, and then for the sake of fixation, alkali is added into the bath at the time of 30 minutes. After 30 minutes' fixing, soap boiling is attempted for 2 times, whose processing conditions are employed as: soap power is 2.0 g/L, liquor ratio is 1 to 50 and the temperature and treating time is 85° C. and 15 minutes respectively.

(13) 2. Form hollow-outs decorative patterns with selected materials which are opaque and thin or thick films by physical or chemical method, so the patterned printing plates are obtained.

(14) Refer to FIG. 1, it is the schematic of a reactor provided by present example, and it is used for achieving patterns on textiles adopting the method of white discharge batch printing. At the bottom of unit of batch processing reactor 2, there is installing an aeration device 6 which continuously passing air into the white discharging bath; In the middle of the reactor, there are installing a tube of quartz 3 and a low-pressure mercury violet lamp 4; the power supply wiring (omitting the power) is connected with the low-pressure mercury lamp which is considered as the ultraviolet light source, and the power of lamp is 8 w.

(15) Closely integrate the hollow-outs patterned printing plates 7 and substrates 5, or the patterned printing plates 7 are fixed in one side or both sides of substrates 5; then put them in a reactor equipped with a light source and make a fine irradiation to the dyed textiles through hollow-outs of the printing-plates' patterns. With the liquor ratio of 1 to 50, the reactor employs the aqueous of potassium persulfate (K.sub.2S.sub.2O.sub.8) whose concentration is 2 g/L as the photocatalytic discharge formulation. After adjusting the pH value to 7, turn on the lamp and hold the temperature of 25° C., then the dyed cotton fabrics are discharged as long as 30 minutes.

(16) Wash and dry the textiles removed from the photocatalytic white discharging bath at room temperature or dry it, then the coloured products with white patterns are obtained.

(17) Instead of potassium persulfate (K.sub.2S.sub.2O.sub.8) used in step 3, form white patterns on textiles with other discharging agents such as hydrogen peroxide (H.sub.2O.sub.2), sodium sulfite (Na.sub.2SO.sub.3), sodium hyposulfite (Na.sub.2S.sub.2O.sub.3), sodium hydrosulfite (Na.sub.2S.sub.2O.sub.4), nano TiO.sub.2 and doping nano TiO.sub.2.

(18) With reference to the processing steps above, regard the experiment of cotton fabrics treated by pure water (i.e. no addition of photocatalytic white discharging agent) as the blank controlled trial, and make a comparison of measurements of whiteness and strength on cottons fabrics treated by photocatalytic discharging agents and the blank sample. The results are as follows.

(19) Measurement of Whiteness

(20) The whiteness of white patterns on the fabrics are measured by Intelligent Digital Whiteness Measurer WSB-3A, choosing three different positions and taking the average value as the fabric whiteness value (R457).

(21) Refer to FIG. 2, it is the schematic of effect of white discharge printing using different white discharging agents with cotton fabrics dyed by Reactive Red X-3B. In the figure: 1 is water (blank controlled trial); 2 is potassium persulfate; 3 is hydrogen peroxide; 4 is sodium sulfite; 5 is sodium hyposulfite; 6 is sodium hydrosulfite; 7 is nano TiO.sub.2; 8 is doping nano TiO.sub.2. From the view of FIG. 2, as the catalysis of ultraviolet light, the ground shade dyes on fabrics can be discharged by the seven different kinds of photocatalytic discharging agents, so as the water. However, there are obvious differences in the whiteness of white patterns. The effect of potassium persulfate, sodium hydrosulfite and sodium sulfite are better, that whiteness values can reach 60 or above.

(22) Measurement of Strength of Fabrics

(23) According to the standard of GB/T 3923.1-1997, the breaking strength of fabrics is measured by Electronic Fabric Strength Apparatus YG026B with the method of strip. Table 1 is the results of breaking strength of dyed fabrics discharged by diverse photocatalytic white discharging agents.

(24) TABLE-US-00001 TABLE 1 Warp-direction strength of dyed fabrics after photocatalytic white discharge printing photocatalytic white Strength of the fabric discharging agent (warp-direction, N) dyed cotton fabric 355.0 blank controlled trial (pure water) 330.0 potassium persulfate (K.sub.2S.sub.2O.sub.8) 324.5 hydrogen peroxide (H.sub.2O.sub.2) 329.0 sodium sulfite (Na.sub.2SO.sub.3) 345.0 sodium hyposulfite (Na.sub.2S.sub.2O.sub.3) 342.5 sodium hydrosulfite (Na.sub.2S.sub.2O.sub.4) 353.0 nano TiO.sub.2 325.5 doping nano TiO.sub.2 331.0

(25) Table 1 reveals a fact that, after the treatment with photocatalytic oxidants, the warp-direction strength of fabrics has been reduced to a certain degree, yet fabrics keep higher tensile breaking strength with the treatment of reducing agents. Due to the oxidizability of ultraviolet light itself accompanying with the effect of oxidants, the loss of fabrics' strength is larger; while the existence of reducing agents reducing the damage on fibers, effect on its strength is less.

(26) As the effect of white discharge printing with system of potassium persulfate is better than other systems, white discharge printing for achieving patterns on dyed cotton fabrics are attempted with the instance of potassium persulfate.

EXAMPLE 2

(27) Some steps are the same of example 1 of the method of photocatalytic white discharge printing for achieving patterns on textiles provided by this invention. In the step 1, the ground shade dye is Reactive Red X-3B; the patterns on printing-plate are lines with different widths or the diamonds (used for the measurement of sharpness of patterns) in step 2; the dyed cottons are white-discharged as long as 35 minutes by the aqueous of potassium persulfate whose concentration is 4.0 g/L and pH value is 10 in step 3. The result can be seen in FIG. 3, the ground shade is red, and the pattern is white lines and cuneate figures with high sharpness.

EXAMPLE 3

(28) Steps of the method of photocatalytic white discharge printing for achieving patterns on textiles provided by this invention can refer to example 1. The pattern on printing-plate is the logo of 2010 Shanghai World Expo in step 2; the dyed cottons are white-discharged as long as 35 minutes by the aqueous of potassium persulfate whose concentration is 4.0 g/L and pH value is 10 in step 3. The result can be seen in FIG. 4, the ground shade is red, and the pattern is a white logo of Shanghai World Expo.

EXAMPLE 4

(29) Steps of the method of photocatalytic white discharge printing for achieving patterns on textiles provided by this invention can refer to example 1. The pattern on printing-plate is a design for snow in step 2; the dyed cottons are white-discharged as long as 35 minutes by the aqueous of potassium persulfate whose concentration is 4.0 g/L and pH value is 10 in step 3. The result can be seen in FIG. 5, the ground shade is red, and the pattern is a white snow.

EXAMPLE 5

(30) Steps of the method of photocatalytic white discharge printing for achieving patterns on textiles provided by this invention can refer to example 1. In step 1, the ground shade dye (dosage of 3.0% o.m.f) is the combination of Reactive Red M-3BE and Reactive Blue 222BF whose mass ratio is 1 to 1, dyeing and fixing at the temperature of 60° C. and 80° C. respectively; the pattern on printing-plate is the logo of 2010 Shanghai World Expo in step 2; the dyed cottons are white-discharged as long as 35 minutes by the aqueous of potassium persulfate whose concentration is 4.0 g/L and pH value is 10 in step 3. The result can be seen in FIG. 6, the ground shade is navy blue, and the pattern is A white logo of Shanghai World Expo.

(31) As can be seen from FIG. 3, FIG. 4, FIG. 5 and FIG. 6, there is no denying that employing the system of UV/K.sub.2S.sub.2O.sub.8 can not only urge the cotton fabrics dyed with a single dye to be discharged, but also it is suitable for the cotton fabrics combination dyed. Furthermore, ideal decorative patterns on fabrics with higher sharpness, white ground noise-free, relaxed cloth and pure color are obtained, just as the same effect of conventional printing.

(32) The invention making a feature of photocatalytic white discharge printing technology, can be implemented on various types of textiles that ground dyed with all kinds of decorative patterns. At the same time, the invention belongs to the typical short and cleaner production process that it eliminates the need for printing pastes and expensive printing apparatuses as well as steaming and desizing, the conventional printing process. Besides, it has the characteristics of simple equipment and process, short processing, and effluent free. Thus, it has a very brilliant prospect of application.