Grassing is one of the oldest methods of bleaching textile goods. The grassing method has been long been used in Europe to bleach linen and cotton based fabrics. [1]
Grassing is one of the oldest methods of bleaching textile goods. The grassing method has been long been used in Europe to bleach linen and cotton based fabrics. [1]
The linens were laid out on the grass for over seven days after boiling with the ''lyes of ashes and rinsing''. [2] The atmospheric oxygen and the oxygen left by the grass provide the whitening action. The cloth becomes whiter day by day until it attains the full whiteness. It was a slow process, but safer for the subjected material. Chemical bleaching may harm the cloth, but in the grassing it hardly affects the cloth's strength. [1] [3] [4]
The Bleachfield was an open area to spread cloth. It was a field near the watercourse used by a bleachery. Bleachfields were common in and around the mill towns during the British Industrial Revolution [5]
With the discovery of Chlorine in the late 18th century, chemical bleaching took over from grassing, as it was quicker and could be done indoors. [1] [5] [2]
It is the conjugated double bonds of the substrate that makes the substrate capable of absorbing visible light. The absorption of light makes the cloth look yellowish. Bleaching with oxygen removes the chromophoric sites and makes the cloths whiter. Oxygen is a degrading bleaching agent. Its bleaching action is based on ''destroying the phenolic groups and the carbon–carbon double bonds.''. [6] A major source of chemical bleaching is hydrogen peroxide (H
2O
2) that contains a single bond, (–O–O–). When the bond breaks, it gives rise to very reactive oxygen specie, which is the active agent of the bleach. Around sixty percent of the world's hydrogen peroxide is used in chemical bleaching of textiles and wood pulp. [7]
Hydrogen peroxide is a chemical compound with the formula H2O2. In its pure form, it is a very pale blue liquid that is slightly more viscous than water. It is used as an oxidizer, bleaching agent, and antiseptic, usually as a dilute solution in water for consumer use, and in higher concentrations for industrial use. Concentrated hydrogen peroxide, or "high-test peroxide", decomposes explosively when heated and has been used both as a monopropellant and an oxidizer in rocketry.
Tie-dye is a term used to describe a number of resist dyeing techniques and the resulting dyed products of these processes. The process of tie-dye typically consists of folding, twisting, pleating, or crumpling fabric or a garment, before binding with string or rubber bands, followed by the application of dye or dyes. The manipulations of the fabric before the application of dye are called resists, as they partially or completely prevent ('resist') the applied dye from coloring the fabric. More sophisticated tie-dye may involve additional steps, including an initial application of dye before the resist, multiple sequential dyeing and resist steps, and the use of other types of resists and discharge.
Dyeing is the application of dyes or pigments on textile materials such as fibers, yarns, and fabrics with the goal of achieving color with desired color fastness. Dyeing is normally done in a special solution containing dyes and particular chemical material. Dye molecules are fixed to the fiber by absorption, diffusion, or bonding with temperature and time being key controlling factors. The bond between dye molecule and fiber may be strong or weak, depending on the dye used. Dyeing and printing are different applications; in printing, color is applied to a localized area with desired patterns. In dyeing, it is applied to the entire textile.
Sodium peroxide is an inorganic compound with the formula Na2O2. This yellowish solid is the product of sodium ignited in excess oxygen. It is a strong base. This metal peroxide exists in several hydrates and peroxyhydrates including Na2O2·2H2O2·4H2O, Na2O2·2H2O, Na2O2·2H2O2, and Na2O2·8H2O. The octahydrate, which is simple to prepare, is white, in contrast to the anhydrous material.
Textile manufacturing is a major industry. It is largely based on the conversion of fibre into yarn, then yarn into fabric. These are then dyed or printed, fabricated into cloth which is then converted into useful goods such as clothing, household items, upholstery and various industrial products.
In organic chemistry, organic peroxides are organic compounds containing the peroxide functional group. If the R′ is hydrogen, the compounds are called hydroperoxides, which are discussed in that article. The O−O bond of peroxides easily breaks, producing free radicals of the form RO•. Thus, organic peroxides are useful as initiators for some types of polymerization, such as the acrylic, unsaturated polyester, and vinyl ester resins used in glass-reinforced plastics. MEKP and benzoyl peroxide are commonly used for this purpose. However, the same property also means that organic peroxides can explosively combust. Organic peroxides, like their inorganic counterparts, are often powerful bleaching agents.
Piranha solution, also known as piranha etch, is a mixture of sulfuric acid (H2SO4) and hydrogen peroxide (H2O2). The result of the mixture gives rise to a strong union of two acids called per-hexa-sulfuric acid (H4SO6) that is used to clean organic residues off substrates. Because the mixture is a strong oxidizing agent, it will decompose most organic matter, and it will also hydroxylate most surfaces (by adding –OH groups), making them highly hydrophilic (water-compatible). This means the solution can also easily dissolve fabric and skin, potentially causing severe damage and chemical burns in case of inadvertent contact.
Textile printing is the process of applying color to fabric in definite patterns or designs. In properly printed fabrics the colour is bonded with the fibre, so as to resist washing and friction. Textile printing is related to dyeing but in dyeing properly the whole fabric is uniformly covered with one colour, whereas in printing one or more colours are applied to it in certain parts only, and in sharply defined patterns.
The textile bleaching is one of the steps in the textile manufacturing process. The objective of bleaching is to remove the natural color for the following steps such as dyeing or printing or to achieve full white. All raw textile materials, when they are in natural form, are known as 'greige' material. They have their natural color, odor and impurities that are not suited to clothing materials. Not only the natural impurities will remain in the greige material, but also the add-ons that were made during its cultivation, growth and manufacture in the form of pesticides, fungicides, worm killers, sizes, lubricants, etc. The removal of these natural coloring matters and add-ons during the previous state of manufacturing is called scouring and bleaching.
Bleach is the generic name for any chemical product that is used industrially or domestically to remove colour (whitening) from fabric or fiber or to clean or to remove stains in a process called bleaching. It often refers specifically to a dilute solution of sodium hypochlorite, also called "liquid bleach".
Bleaching of wood pulp is the chemical processing of wood pulp to lighten its color and whiten the pulp. The primary product of wood pulp is paper, for which whiteness is an important characteristic. These processes and chemistry are also applicable to the bleaching of non-wood pulps, such as those made from bamboo or kenaf.
A bleachfield or bleaching green was an open area used for spreading cloth on the ground to be purified and whitened by the action of the sunlight. Bleaching fields were usually found in and around mill towns in Great Britain and were an integral part of textile manufacture during the Industrial Revolution.
In textile manufacturing, finishing refers to the processes that convert the woven or knitted cloth into a usable material and more specifically to any process performed after dyeing the yarn or fabric to improve the look, performance, or "hand" (feel) of the finish textile or clothing. The precise meaning depends on context.
Lightfastness is a property of a colourant such as dye or pigment that describes its resistance to fading when exposed to light. Dyes and pigments are used for example for dyeing of fabrics, plastics or other materials and manufacturing paints or printing inks.
Dimethylol ethyleneurea is an organic compound derived from formaldehyde and urea. It is a colourless solid that is used for treating cellulose-based heavy fabrics to inhibit wrinkle formation. Dimethylol ethylene urea (DMEU) bonds with the hydroxyl groups present in long cellulose chains and prevents the formation hydrogen bonding between the chains, the primary cause of wrinkling. This treatment produces permanently wrinkle-resistant fabrics and is different from the effects achieved from using fabric softeners. An additional names for DMEU includes 1,3-bis(hydroxymethyl)-tetrahydro-2-imidazolone.
Colour fastness is a term—used in the dyeing of textile materials—that characterizes a material's colour's resistance to fading or running. Colour fastness is the property of dyes and it is directly proportional to the binding force between photochromic dye and the fibre. The colour fastness may also be affected by processing techniques and choice of chemicals and axillaries.
Wet Processing Engineering is one of the major streams in Textile Engineering or Textile manufacturing which refers to the engineering of textile chemical processes and associated applied science. The other three streams in textile engineering are yarn engineering, fabric engineering, and apparel engineering. The processes of this stream are involved or carried out in an aqueous stage. Hence, it is called a wet process which usually covers pre-treatment, dyeing, printing, and finishing.
Green textiles are fabrics or fibres produced to replace environmentally harmful textiles and minimise the ecological impact. Green textiles are part of the sustainable fashion and eco-friendly trends, providing alternatives to the otherwise pollution-heavy products of conventional textile industry, which is deemed the most ecologically damaging industry.
A peroxide-based bleach or simply peroxide bleach is any bleach product that is based on the peroxide chemical group, namely two oxygen atoms connected by a single bond, (–O–O–). This bond is fairly weak and is often broken in chemical reactions of peroxides, giving rise to very reactive oxygen species, which are the active agents of the bleach.
Scouring is a preparatory treatment of certain textile materials. Scouring removes soluble and insoluble impurities found in textiles as natural, added and adventitious impurities, for example, oils, waxes, fats, vegetable matter, as well as dirt. Removing these contaminants through scouring prepares the textiles for subsequent processes such as bleaching and dyeing. Though a general term, "scouring" is most often used for wool. In cotton, it is synonymously called "boiling out," and in silk, and "boiling off."
Grassing . — The oldest bleaching method is that of " grassing , " still used to a certain extent in Europe for bleaching linens. The linen fabrics are laid on the grass or ground for weeks . The oxygen of the air and that given off by green plants