What is Resist Printing in Textile: Advantages and Disadvantages

What is Resist Printing in Textile?

Resist printing is a method where you prevent dye from reaching certain areas of the fabric to create patterns. In resist style of printing, the design portion in the fabric is blocked with some substances, which physically or chemically resist penetration of colors in those areas. After resisting selected portion of the fabric, it is quickly passed through dye liquor and the color is fixed by a suitable method. The resisted portion may be colorless (white resist) or colored (color resist) if suitable colors are applied along with the resisting agent. An example of resist printing is batik printing in which wax is used as a resisting agent.

Resist or reserve printing can be used to produce white or multicolor print. Instead of applying print paste in the design portions, as in case of direct style of printing, the design portions are printed with resisting agents or suitably covered, thereby block­ing or resisting physically or chemically the penetration of dyes in those portions. The remaining portions are then dyed quickly by short dipping or nip padding of the resisted fabric. The dyes in non-design portions are subsequently fixed by a suitable method, followed by washing to remove resisting agents and unfixed dyes.

Resist printing is related to discharge printing in that the end-results are often indistinguishable. In this method, the scoured and/or bleached fabric is first printed with a paste con­taining a resisting chemical (mechanical and/or chemical resist) like wax, china clay, acids, alkalis and so on that resists the penetration and fixation of dyes into the fabric. The printed fabric is then quickly dipped or padded in dye bath, so that the resisting agent remains unaffected and only the resist-free areas are dyed. After dyeing and fixation processes, the resist paste is removed, leaving white patterns on a dark back­ground; this style is called white resist. A second dye may be added in the resist paste which fixes in the resisted area giving colored patterns on a dark background. This style is called color resist (i.e., multi-color effect). Two most popular resist styles of printing are “Batik printing” and “tie and dye” style of printing.

Historically resist printing were practiced in printing methods like batik printing. These were physical resist printing where (hydrophobic) products or printing pastes were applied to the fabric to avoid contact and penetration when the fabric was subsequently immersed in the dyeing liquor. Now, main resist printing systems are chemical resist printing where pastes containing chemicals, which avoid fixation of background dyes (particularly for “reactives on reactives” applied on fabrics made of cellulose fibers). Examples of resisting chemicals include acids, alkalis, oxidising or reducing agents. These chemicals react with the dye, the fiber, or with the dyeing auxiliaries and prevent dye fixation. Resist printing style can give a discharge effect in a different way. It involves two steps.

1. The fabric is first printed with a resisting agent which function either mechanically or chemically or, sometimes, in both ways and resist the dye penetration to the substrate or dye fixation.
2. Piece dye the fabric with the ground shade by an appropriate ‘dyeing’ technique, such as dyeing, padding or overprinting where by the substrate gets dyed at the areas which is not covered with the prints.

Advantages of this style of print are that since there is no discharge is involved almost all dyes can be used, hence dyes of great chemical stability, which cannot be discharged can be resisted and prints of high fastness standards can be produced. Thus shade ranges become much broader and the end results of these prints are often indistinguishable.

Resist Printing Techniques:

Some of the resist printing techniques are detailed in the following:

Resist printing on covered background:

This refers to the removal of a dye previously mechanically applied to the fiber by the subsequent application of a printing paste. These may be viewed as chemically-enhanced “displacement prints”; it is not only a mechanical displacement which takes place, which at best gives rise to tone-in-tone brightening. Special chemicals or auxiliary agents, which possess dye or fiber affinity, given the relevant pH, may in addition prevent the fixation of the dye of the previously applied background dye. The background can hereby be applied using a nip pad or, using a blotch printing template if required. The process involves in a pad dye is applied and dried; the printing is carried out with printing pastes containing products avoiding the fixing of background color (but they do not avoid the fixing of any brightener used). The fabric is then dried, steamed and washed (this is the most diffused resist printing method).

1. Resist printing by overdyeing:

The operations of the resist printing method previously detailed are carried out in reverse sequence; therefore the fabric is first printed and then covered.

2. Resist printing by overprinting:

This method is similar to the previous one, but the covering operation is replaced with the roller printing of the background.

3. Printing on polyester:

Polyester printing must be carried out applying the resist-discharge printing method. Printing pastes containing both the discharge and resist products applied on covered background must be used.

4. Overprint/applied print resists:

The methods can be subdivided into single-stage wet-on-wet processes with or without intermediate dye fixing and two-stage processes, by which printing is carried out first, and the goods are subsequently continuously or batch process overdyed.

Since the print paste is printed of the fabric surface, and dried before the dyeing operation, the resist paste on the fabric surface must obviously be stable under the dyeing conditions. It is therefore preferable to use materials that are not too readily soluble in water and to modify the dyeing process.

Nip pad or over printing application of dye reduces the time of contact and therefore the bleeding of soluble resist agents. The dye liquor is padded on the fabric by relatively mild method. Nip-padding is one method of applying the ground color without large amounts of water being present. The fabric does not pass through the pad bath but directly between the pad rollers. The lower roller dips into the bath, picks up a somewhat thickened solution (some thickening of the pad liquor may be necessary to increase the volume of liquor carried on to the fabric) of the dyes and transfers it uniformly to the fabric. This avoids the fabric passing through long pad bath there by the print getting affected and distorted affecting the print pattern. Other precautions are also taken to avoid softening or bleeding of the print paste like temperature of the dye solution must also be kept low, and it is often necessary to dry the fabric immediately after application of the dye. Use of an engraved cover roller, known as overprinting roller or blotch printing using a rotary screen, provides an alternative to nip padding and one stage in the process may be eliminated if drying of the resist is not essential.

There are two different types, pre-printed and over-printed resists, depending on whether the resist print paste was applied before or after preparation of the fabric with dye solution. In both cases, the dyeing of printed areas is prevented. The resists used in resist or reserve printing can be broadly grouped in to three categories:

1. Mechanical resists (paste resists): Wax reserves (resin, wax, etc.) block dye access to the printed areas mechanically.
2. Chemical resists: Break down the chemicals required for dye-fixing on printed areas.
3. Chemical-mechanical resists: Combination of I and II.

As well as breaking down the dye-fixing chemicals, insoluble salts are usually formed as well as an extra layer of protection. Mechanical resists use resisting agents like waxes, fats, resins, thickeners and pigments, such as China clay, the oxides of zinc and titanium, and sulphates of lead and barium.

Such mechanical resisting agents simply form a physical barrier between the fabric and the colorant. They are mainly used for the older, coarser and, perhaps, more decorative styles in which breadth of effect and variety of tone in the resisted areas are of more importance than sharp definition of the pattern. A classical, and nowadays almost unique, example of a purely mechanical resist is to be found in the batik style, using wax applied in the molten state. In a true batik the wax is applied by hand, but the process has been developed and mechanised for the production of those styles which now come under the general heading of ‘Africa prints’. Since the wax cannot be mixed with dye colored resists by wax method is mostly impossible. But in a laborious process, the white resist is done with a wax resist and after removal of the wax, another color can be printed within the resisted area or dyed in a different color where by the white resisted area will have the color dyes and other portion will have mixed with. A mechanical resist is usually used in conjunction with a chemical resist, so improving the overall effect.

Wax resists consist mainly of natural resins (pine resin, colophony), beeswax, ceresin, stearin, spermaceti, tallow, etc. melted with turpentine oil or rectified petroleum. These waxes can be applied on the substrate by block printing or in some cases with heated rollers with deep engravings on a roller printing machine. The fabric can be sprinkled with kaolin, diatomaceous earth or fuller’s earth to avoid sticking and smearing. Where the crackling effect is required fabric is printed with a wax resist, then cooled down quickly in cold water and subjected to a mechanical breaking action in order to achieve the typical crackle effects (fine veining). It is subsequently dyed, usually with cold dyeing dyes like selected acid (silk) , reactive, basic, direct or mordant dyes as well as indigo. If the wax is removed by solvent (e.g., benzene), the dyes used should not soluble in it. Many times the wax is removed by dipping in hot water. After squeezing-off or centrifuging, the fabric is dried (steamed if necessary) and hung. Cationic dyes are dyed under neutral or weakly acidic (acetic acid) conditions in 2–4 h (and treated in cold tannin and tartar emetic baths if necessary). Acid dyes are dyed with 20% formic acid 90% based on the weight of dye for 30 min followed by another acid addition and dyeing for a further 30 min. For discharge batiks, dyed and batiked silk is allowed to lie in a cold bath containing 20–30 g sodium dithionite, removed after 30–45 min, 4–5 ml/l sulphuric acid 78.5% added, and the fabric treated for 15 min, after which it is rinsed and the cracked wax resists are dyed with another color in a fresh bath (using acid or substantive dyes).

Paste resists are also comes under mechanical resists where pre-printed resist made of many high solids thickeners, thickener containing a weighting agent (e.g. kaolin, zinc oxide, lead carbonate, etc.) used in dyeing with indigo and vat dyeing.

Chemical resists: Chemical-resisting agents include a wide variety of chemical compounds, such as acids, alkalis, various salts, and oxidising and reducing agents. They prevent fixation or development of the ground color by chemically reacting with the dye or with the reagents necessary for its fixation or formation.

Chemical-Mechanical Resists: a resist usually used for indigo resist can explained to illustrate a chemical – mechanical resists using indigo for the ground. Resist paste will contain high solid thickener like British Gum or gum Senegal, China clay and tallow (if necessary) together which acts as a mechanical resist together with a copper salt like copper sulphate which acts as an oxidising agent, which acts as a chemical resist. The resist paste is printed on an RFP fabric pre-treated with starch and calendered fabric to give a flat surface upon which the resist print would form a more perfect protective cover, and dried. On thorough drying the printed portion forms a resist barrier. The printed, dried fabric is dyes with indigo dye vat several times oxidising the dye in between to get the required depth. As indicated earlier the resist print acts in two ways: the mechanical part of the resist prevent the indigo leuco vat to reach the fabric at the same time the oxidising agent would convert the leuco form into an insoluble form which again deposit inside the resist print making the resist more effective than earlier. The fabric is oxidised for the indigo to fix on unprinted areas and then the resist is washed off from the fabric after soaking thickener well. Resist printing pastes usually have a high solids content. Because of this, they have a tendency to stick in fine engravings or block screens. It is common practice to strain the paste through a screen finer than the printing screen to avoid the latter problem. Stork (rotary screen manufacturer) suggests to use Penta 155 mesh screen in their range for blotch printing (Over print resist) and for discharge and resist printing.

Colored resists equivalent to colored discharges are possible by incorporating dyes or pigment and binder along with the resist paste. A colored resist with pigment dye on a reactive ground possible by adding pigment and binder in the print paste containing acid. After printing, the material is nip padded or overprinted with reactive dyes and bicarbonate solution or paste fabric steamed without drying. The acid in the printed portion prevents the fixation of reactive dyes at the printed patterns and at the same time the acid present in the print paste help the pigment and binder to form a resistant film while steaming the print. The alkali present in the unprinted portion help the reactive dye to react with the cotton and fixation while the printed areas have the color of the pigment held on the surface by the binder film.

The reaction of sodium bisulphite on vinyl sulphone dyes open the ways to resist print a reactive dye over a reactive dyes which otherwise appear to be impossible. The same reaction is not applicable to chlorotriazine dyes makes the above printing possible.

In practice, the print paste containing the chloro-triazine reactive dyes, sodium bicarbonate and sodium bisulphite is printed and dried. The material is over printed with a paste containing the vinyl sulphone dyes and alkali. The fabric is dried and steamed.

During the steaming the chlorotriazine dye reacts with the cotton aided by the sodium carbonate that is formed in the resist printed areas but the sodium bisulphite also present inhibits the reaction of the vinyl sulphone dye. The latter only colors the ground where bisulphite is absent.

Mechanism of Resist Printing in Textile:

Resist mechanisms may be chemical or physical, the maximum effectiveness being ensured by using a mixture of both types of resist agent. A physical resist inhibits absorption of dye, and a chemical resist inhibits fixation. Colored resists require the addition to the print paste of dyes or pigments that are satisfactorily fixed in the presence of the resist agent, either before the fixation of the ground color or during the process. If the ground color is not too dark, it may be that the required effect is obtainable by “overprinting”. This is simply direct printing onto a pre-dyed fabric. Tone-on-tone effects, which use colors of similar hue, are often produced in this way, but contrasting color combinations are also possible. For example, blue dyes may be printed on to a yellow fabric to obtain green areas. Overprinting requires no elaboration, but discharge and resist styles must be considered in more detail if the full range of possibilities and problems are to be appreciated and understood.

The mechanical resisting agents commonly used in resist printing are waxes, fats, resins, thickeners and pigments, such as china clay and the oxides of zinc and titanium. Such mechanical resisting agents simply form a physical barrier between the fabric and the colorant. They are mainly used for the older, coarser and, perhaps, more decora­tive styles in which breadth of effect and variety of tone in the resisted areas are of more importance than sharp definition of the pattern. A classic, and nowadays almost unique, example of a purely mechanical resist is batik printing, using wax applied in the molten state. In a true batik the wax is applied by hand brush, but the process has been developed and mechanized for the production of styles that now come under the general heading of “African prints”. It is not possible to apply an illuminating color with a wax resist but, after removal of the wax, another color can be printed within the resisted area by rewaxing and redyeing.

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Chemical-resisting agents include a wide variety of chemical compounds, such as acids, alkalis, various salts, and oxidizing and reducing agents. They prevent fixa­tion or development of the ground color by chemically reacting with the dye or with the reagents necessary for its fixation or formation. The actual choice of chemical-resisting agent depends, therefore, on the chemistry of the dye being used and its fixation mechanism. Consequently, as in discharge printing, a working knowledge of the relevant chemistry is necessary when choosing effective resisting agents.

Most reactive dyes can only be fixed on cellulosic fibers in the presence of alkali. Consequently, nonvolatile organic acids (such as tartaric or citric acid) and acid salts (such as monosodium phosphate) may be used as resist agents for preprint resists under such dyes. Hence, the thickeners used should be acid-resistant. Hydroxyethylated and methylhydroxyethylated cellulose ethers, locust bean gum and tragacanth are suit­able for this purpose. When printing with deeply engraved rollers the concentration of acid- or alkali-binding substance can be kept low, but an increase in the concentration may be required if sharp effects are to be obtained with shallow engravings. A typical preprint resist paste would have the composition as shown in the following recipe:

• Citric acid ————–50 g
• Thickener ————–600 g
• Water to —————1,000 g

The colorless resist print pastes may be made visible by tinting with a fugitive dye such as CI Acid Blue 1, or by adding a fluorescent brightener, which is detected with the help of an ultraviolet lamp.

After the material has been printed and dried, it is nip-padded, overprinted or padded with a solution of a high-reactivity reactive dye containing a minimum concentration of sodium bicarbonate. If the material is to be immersed in the dye liquor, it may be necessary to increase the acid concentration in the print paste to 80 g/kg paste. Immersion times should be short. Drying must follow immedi­ately; then an appropriate fixation step and washing. A typical padding liquor is as follows:

Certain alkali donors may be employed instead of sodium bicarbonate, in which case the steaming time should be increased to 7–10 minutes to allow for adequate breakdown of such compounds and subsequent fixation of the dye.

Colored resists under reactive dyes can be produced by pre-printing the fabric with a pigment print paste containing an acid to act as resist agent. The pigment binder should preferably be one that can be fixed by steaming. A typical stock paste will be made up as shown in the following recipe:

The actual print paste would be prepared from this stock paste by adding the requisite quantity of pigment emulsion. The sequence of resist printing operations would then be as follows:

1. Preprint with pigment paste containing acid
2. Pad with reactive dye, after intermediate drying, or overprint without drying
3. Steam for 2–10 min according to the reactivity of the dye used
4. Wash-off
5. Dry

The recipe uses an emulsion thickening system, but due to environmental legislation, restrictions as to the use of systems based on white spirit resulted in the promotion of further developments using aqueous systems based on synthetic thickeners. Prior to this, the synthetic thickeners used to prepare aqueous pigment thickeners were unacceptable as the acid required for the resist produced an unacceptable drop in viscosity.

Vat resists under vat-dyed grounds are not a widely used style, but it has been, and could be, used where the fastness properties associated with vat dyes are neces­sary. The material is first printed with a normal all-in vat print paste with addition of sodium thiosulfate. After steaming, to reduce the vat dye, the material is padded in a solution containing a vat leuco ester and sodium nitrite, followed by passage through a sulfuric acid solution. The alkali in the vat print neutralizes the acid and the sodium thiosulfate is preferentially oxidized, preventing development in the printed areas. The goods are finally after-treated in the normal manner prescribed for vats.

Advantages and Disadvantages of Resist Printing:

The advantages of resist printing are:

1. Multi-color effect can be obtained at lower costs.
2. The process is much simpler and cheaper than discharge printing.
3. Less stable dyes are used as ground color in discharge style of printing. On the other hand, in resist style of printing, even though stable dyes are used, the contact time of the fabric with dye solution is much less and hence, the wash fastness of colors is lower than those in case of direct styles of printing.

The disadvantages of resist printing are:

1. The performance of resisting agents is limited. Hence, ground colors may penetrate in some portions of the resisted or printed area thereby hampering printing perfections.
2. It is labor-intensive process, specially in hand-done techniques like Batik and Tie-Dye.
3. Requires skilled labor and specialized materials.
4. Difficult to achieve highly detailed or sharp patterns.
5. Improper resist application may lead to color spread.

Conclusion:

Resist printing is a versatile and artistic textile printing technique that allows for intricate, multicolored patterns by selectively blocking dye penetration. This method allows for unique, often handcrafted designs and is widely used in both artisanal and industrial textile production. Resist printing is widely used in Dresses, scarves, and bohemian-style clothing, curtains, bedspreads, tablecloths, custom wall hangings, tapestries, and DIY projects.

References:

[1] Kolanjikombil, M. (2024c). Printing of textile substrates: Machineries and Methods. CRC Press.

[2] Textile and Clothing Design Technology. (2017). In CRC Press eBooks. https://doi.org/10.1201/9781315156163

[3] Choudhury, A. K. R. (2022). Principles of Textile Printing. CRC Press.

[4] Miles, L. W. C. (2003a). Textile Printing. Amer Assn of Textile.

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