Preface
Acid dyes are often used in the direct printing of nylon, which have the advantages of complete chromatogram and bright color. However, there are still some shortcomings, such as poor color fastness, the need for fixation, and the heavy tasks of soaping and washing in the post-treatment process. When soaping, the analysis of dyestuff will not only cause the color of printing area to be stained with each other, but also the white bottom of non printing area to be stained with color, resulting in poor whiteness of fabric white bottom. Binder has been widely used in pigment printing, and its properties determine the hand feeling and color fastness of pigment printing fabric. The modification of adhesives has always been a research hotspot, mainly including interpenetrating network adhesives of polyurethane and polyacrylate, acrylate adhesives modified by polyurethane, acrylate adhesives modified by silicone and core-shell structure adhesives, and acrylate adhesives modified by vinyl silicone oil and fluorosilicone for silk paint printing.
In order to improve the fixation rate of acid dyes and fibers, reduce the floating dyes on the fabric surface, and prevent the dye from staining the fabric when it is soaped or washed by water, based on the technical principle of polyester "micro printing" method, this paper puts forward the pretreatment of nylon fabric with fixing agent, so as to prevent or inhibit the re staining of the desorption dyes. At the same time, the adhesive is added to the printing medium to explore its application. Effect on dye fixation. In this paper, the effect of some binders on the printing performance of acid dyes was studied under the optimal steaming condition, and the effect of pretreatment of some fixers on the printing performance was compared. The principle of the optimal binders and fixers was also preliminarily investigated, which provided a feasibility for developing the printing process with low water consumption.
1. Test part
1.1 materials, reagents and instruments
Fabric 210t white spun nylon fabric (commercially available)
1.2 test method 1.2.1 fixation pretreatment
Technological process
Fabric → color fixing agent impregnation → centrifugal dehydration → drying
Process prescription
Fixing agent /% OMF x
Bath ratio 1:50
Immersion temperature room temperature
Immersion time / min 10
Drying temperature / ℃ 70
Drying time / min 5
1.2.2 printing
1) process flow a
Fabric → printing → drying → steaming → soaping → washing → drying → finished product
2) conventional process flow
Fabric → printing → drying → steaming → soaping → washing → drying → finished product
3) printing process prescription
Thickener ptf-a /% OMF 2
Adhesive /% OMF x
Acid red 315 /% OMF 0.3
Steam temperature / ℃ 100
Steam humidity /% 100
Steam time / min 20
4) soap washing process
Standard detergent / g · L - 14
Temperature / ℃ 50
Time / min 45
Bath ratio 1:50
5) fixation process
Fixing agent tfc-1 /% OMF 1
Temperature room temperature
Time / min 10
1.3 performance test 1.3.1 color fastness
The color fastness to rubbing shall be determined according to GB / t3920-2008 color fastness to rubbing test for textile products, and graded according to gb251-1995 grey sample card for assessment of staining. The color fastness to soaping shall be determined in accordance with GB / t3921-2008 color fastness to soaping test for textile products.
1.3.2K/S value
The K / s value was measured on the ultrascanxe computer colorimeter. The test conditions are D65 light source, 10 ° viewing angle, folding the sample into 4 layers, measuring 5 times, taking the average value. The relative fixation rate (RF) of dye is calculated according to formula (1), and the floating color of fabric surface is characterized.
1.3.3 whiteness
Measured on ultrascanxe computer colorimeter.
2. Results and discussion
2.1 effect of binder on printing performance of nylon
In section 1.2.2, process a is used to print the fabric. The effects of three adhesives with different mass fractions on the K / s value, dye relative fixation rate and color fastness of the printed fabric before and after soaping are studied. The results are shown in Table 1.
It can be seen from table 1 that binder has a great influence on K / s and dye relative fixation rate of nylon printed fabric. Compared with no binder, the K / s value and relative fixation rate of the three binders were significantly increased. Among them, binder S-6 has the most obvious effect on the improvement of K / s value and dye relative fixation. Adding three kinds of adhesives can improve the fastness to rubbing and soaping, and the difference is not significant. To sum up, choosing adhesive s-61% OMF can achieve better printing effect.
2.2 effect of fixing agent pretreatment on printing performance of nylon
The fabric was pretreated according to the fixation process in section 1.2.1, then printed in section 1.2.21, adhesive s-61% OMF. The effects of three kinds of fixation agents with different mass fractions on the K / s value, dye relative fixation rate, non printing area whiteness and color fastness of the fabric before and after soaping were studied. The results are shown in Table 2.
It can be seen from table 2 that after fix-3cmr pretreatment, the whiteness of the fabric decreases with the increase of the mass fraction of fixing agent, while tfc-1 has little effect on the whiteness of the fabric. The whiteness of the untreated fabric decreased obviously after soaping, which indicated that the dye absorbed during soaping had obvious contamination on the non printing area. Compared with the untreated fabric, the K / s of the fabric pretreated by three kinds of fixing agents before soaping decreased, while the K / s value of the fabric pretreated by tfc-1 after soaping increased. The dye fixation rate of fabric treated with tfc-1 is over 99%. After pretreatment with three kinds of fixing agents, the soaping fastness of the fabric can be improved by 0.5 grade. To sum up, when the mass fraction of fixing agent tfc-1 is 1%, the printed fabric can obtain higher K / s value and dye relative fixation rate, and has excellent dry wet rubbing fastness (grade 4-5).
2.3 function of fixing agent and adhesive in printing
The fabric was pretreated according to the fixation process in section 1.2.1, then printed in section 1.2.2 process a, and compared with the fabric treated by the conventional printing process in section 1.2.2. Tfc-11% OMF). Determine whether there is adhesive S-6 and the printing performance of the fabric before and after soaping. See Table 3 for the results.
It can be seen from table 3 that after the conventional printing process is soaped, the K / s and whiteness of the fabric decrease greatly, and the relative fixation rate of the dye is the lowest, which shows that the surface of the conventional printing fabric has more floating color, and the dye desorption is large during the soaping process, resulting in the lighter color of the fabric and the more serious white staining. In the conventional printing process, the whiteness of the fabric decreased after soaping with adhesive S-6, which indicated that there was still a significant phenomenon of white ground staining, but the K / s value and the relative fixation rate of the dye were significantly increased. After treated with tfc-1, the color fastness to soaping was improved by 0.5 grade, and the color fastness to dry rubbing before and after soaping was up to 4 grade, which indicated that adhesive S-6 could improve the interaction between dye and fiber and reduce the desorption of dye during soaping. After pretreatment with tfc-1, the whiteness of the fabric changed little after soaping, and the K / s value and dye relative fixation rate were higher. When the binder S-6 is added to the printing paste of the pretreated fabric, the whiteness of the fabric after soaping changes less, and the K / s value and dye fixation ratio are higher. At this time, the dry rubbing fastness, wet rubbing fastness and soaping fastness of the fabric before soaping reach 4-5, 4-5 and 4-5 respectively, and the influence of soaping on the rubbing fastness is less.
To sum up, the treatment of nylon printed fabric with fixing agent can not reduce the floating color on the surface of the fabric, nor improve the staining of the desorption dye on the fabric; while the printing fabric with fixing agent pretreatment and adding binder not only has high color fastness, but also can effectively prevent white staining, and improve the K / s value of the fabric and the relative fixation rate of the dye. Therefore, it can greatly reduce or even eliminate the conventional post printing soaping process, and only through simple water washing to remove the residual auxiliaries on the fabric surface, excellent printing effect can be obtained. This provides a possibility for black-and-white printing of nylon and a new processing method for post-treatment of printing with low water consumption.
3. Conclusion
1) the binder S-6 with 1% OMF) in printing paste can significantly improve the K / s value, dye relative fixation rate and color fastness of the fabric.
2) the pretreatment with 1% OMF fixing agent tfc-1 can improve the whiteness of printed fabric, which has obvious anti staining effect, and can also improve the relative fixation rate of dye, up to 99%, and the color fastness of printed fabric can reach 4-5 grades.
3) the pretreatment with fixing agent tfc-1 and the printing process with binder S-6 have little effect on the whiteness of nylon fabric during soaping, which can effectively prevent dye staining, improve the K / s value and dye relative fixation rate of the fabric, and obtain excellent color fastness. Compared with the conventional process, the new process can greatly reduce the floating color of the fabric surface, effectively reduce the burden of soap washing and water washing tasks after conventional printing, which is a low water consumption nylon printing method.