Dyeing and printing are surface decoration processes that add color and patterns to textiles. As a local dyeing, the main purpose of the printing is to use one or more non-colored art designs to produce a pattern with clear boundaries.
In ancient times, or before inventing synthetic dyes, only natural dyes extracted from plants, animals or minerals can be used for textile printing. Since 1856 W. After Perkin invented the synthetic pigments, the use of natural dyes as textile dyes was time-consuming and labor-consuming and could not be pre-manufactured. Therefore, it gradually lost its important position.
However, in 1996, Germany began to ban certain azo dyes. It has been found that these dyes are carcinogenic, teratogenic and sensitizing. Therefore, people turn their attention to “environmentally friendly†dyes. The re-introduction of natural environment-friendly dyes opens up new opportunities for the textile industry to use these dyes to open up new markets for natural dyeing products. The natural textile product market is a huge market to be fully developed. To make full use of these natural resources, we need to work together to develop corresponding technologies, processes and products. At present, most researches are focused on the dyeing of natural dyes and the improvement of the color fastness of dyeing products, but rarely on the application of printing. This study only involved the application of four natural dyes in printing, as well as products for the production of silk and cotton printed fabrics, including apparel, home textiles and handicrafts. The study provides another new way to produce high value-added products.
2 test content
Fabrics: Cotton and silk fabrics.
Dyes: The four natural dyes originate from Berberis Vulgaris, Juglans regia, Hamelia patens and Jatropha int garrinma, respectively. They are used for dyeing and printing on grey cloths. Among them, Rubiaceae shrub leaves and Jatropha curcas were collected from roadside shrubs on Pantnagar's university campus, while walnut bark and berberine roots were collected from the Kumaon hills.
Pharmaceutics: hydrochloric acid and sodium carbonate are used for the extraction of dyes, alum and copper sulphate and ferrous sulphate are used as mordants.
Paste: Long rubber.
2.1 Fabric Pretreatment
2.1.1 Pretreatment of Cotton Fabrics
Scouring and desizing: Soak the fabric in water overnight before dyeing and printing to remove the natural and added impurities that affect the printing. Then in a bath containing 2g/L soap and 1g/L NaOH for 45 minutes. Cherry Plum Treatment: Cherry plum (4% of fabric weight) is soaked in water overnight and then filtered. The fabric was treated in a filter solution at a bath ratio of 1:20 for 1 h and then dried in the sun.
2.1.2 Pretreatment of Silk Fabrics
Degumming: Silk fabrics were pretreated in a 0.5% (v/v) solution of gentee 1 at a temperature of 50°C for 30 minutes. The fabrics were manually kneaded, squeezed, and rinsed with water until the detergent was washed. The fabric should be ironed when it is dry and semi-wet.
2.2 Paste Preparation
The 250 g of dragon rubber was soaked in 1 L of water overnight, fully stirred after swelling, and filtered with a fine cloth to make a clarified slurry.
2.3 dye extraction
The dye is extracted from natural plants using the preferred extraction method (acid hydrazine concentration, optimum raw material concentration and extraction time) to achieve the best color yield and color fastness.
2.4 color concentrate preparation
The clarified extraction solution is heated and concentrated to obtain a dye concentrate. 100 mL of the extraction solution was concentrated to 5 mL.
3 Product Development
The product line includes: clothing, home textiles and handicrafts. The fabric is printed with a natural dye, preferably a printed formulation screen. The product can also be embroidered to add value. Development of apparel products include shirts, short-sleeved collarless shirts and sarees. Home textile products have bed sheets and cushion covers. Handicrafts have a diary cover and siding.
3.1 Clothing
The shirt is made of cotton, and the berberine root pigment is printed with a synchronous mordant method. The mordant is made of ferrous sulfate. The short-sleeved no collar shirt is made of pure silk. The walnut bark pigment is dyed with a synchronous mordant method, and the mordant is made of copper sulfate. Sari cotton sari is dyed with berberine root pigment and walnut bark pigment printing, using synchronous mordant method. Printing mordant with copper sulfate.
3.2 Home Textiles
Sheet cotton sheets are dyed with walnut bark pigment and jatropha anthocyanin. Synchronous mordant method is used. Alum and ferrous sulfate are used for the printing mordant.
Cushion cover silk was dyed with berberine root pigment and alum mordant. Printing Jatropha anthoflora and ferrous sulfate mordant, synchronous mordant printing.
3.3 Handicrafts
The cover of the diary was made of real silk dyed with berberine root pigment. The mordant was made of alum and printed with the zephyr anthocyanidin and ferrous sulfate mordant. The siding is made of pure silk and printed with jatropha, yucae shrub leaves, and berberine root pigments, and mordant with alum.
4 test results
The natural dye printing of textiles seems to have attractive prospects, but practical applications include printing on silk fabrics to evaluate the fastness of printed samples.
According to the above formula, different printing pastes are prepared, and the screen printing process is used for pre-mordant printing and synchronous mordant printing. After printing, dyestuffs are steamed and fixed, then thoroughly washed and floated, dried and evaluated for color fastness.
The color fastness of berberine root, walnut bark, jatropha, and alfalfa shrub leaf pigments on cotton fabrics range from acceptable to good, but the color fastness on silk is still good to good, using pre-mordant dyeing and Synchronous mordant results are the same.
Pre-mordant dyeing of cotton fabric samples showed good color fastness to washing. In the worst case, silk fabrics are still good, while the dyeing fastness of cotton fabrics using synchronous mordant dyeing is still good, and silk fabrics are still good. To good. Regardless of the pre-mordant dyeing method or the synchronous mordant dyeing method, no coloration was found on cotton fabrics and silk fabrics. Therefore, it can be considered that the water fastness of samples of the synchronous mordant method is better than that of the pre-mordant samples. Among all the natural dyes for printing, the washfastness of leaf pigments of berberine tree roots and sedge shrubs color fastness pigment pigments of bark bark and jatropha curcas.
The results of the rubbing fastness test on pre-mordant dyed samples of all dyes showed that the discoloration on the cotton and silk fabrics was slight to negligible. The wet-friction color fastness of the pre-dyed dyed cotton cloth samples of all dyes was slightly stained, and the dry-friction color fastness was non-staining. The wet rub fastness of berberine root pigment on the silk fabric was stainless, while the leaf pigments of walnut bark, jatropha curcuma and rubiaceae shrub were slightly stained on the silk fabric. None of the four dyed pre-printed silk samples were stained in the dry state. The color fastness to rubbing of the samples of the synchro- metric mor- phology showed that all the dyes had excellent color fastness. The color fastness to dry rubbing of cotton and silk synchro- metric samples was negligible, while the wet rubbing fastness was slight to negligible. Therefore, try
The test results showed that the frictional color fastness of synchronous mordant printing samples was better than that of pre-mordant dyeing printing samples.
The berberine root and jatropha anthocyanin were printed on cotton and silk fabrics using a synchronous mordant method. The perspiration fastness was better than that of the walnut bark and comfrey leaf pigments. Therefore, the following conclusions can be drawn: Synchronized media for cotton and silk printing
The dyeing method is better than the pre-mordant dyeing method.
5 Conclusion
Printing is one of the oldest ways to make fabrics colorful. This study shows that the natural dyes extracted from berberine root, walnut bark, jatropha, and velutinaceous shrub leaves have been used for dyeing textiles. These dyes can also be used for printing on cotton and silk fabrics. These natural dyes can form a variety of soft, light and crockfastness prints on cotton and silk that can meet general requirements.
Reprinted from: China Printing and Dyeing Chemicals Network