Stuff printing
The fabric printing (fabric printing) is a process to produce designs (colored patterns ) on fabrics by textile printing . Stuff is an ancient term for fabrics made of cotton or linen .
process
Stuff printing is based on the same principles as dyeing , but the patterns are produced in very different ways. In the simplest case, the square block of wood on which the pattern is applied as a relief is used to apply the paint or stain . You either cut the same directly into the hard wood of the so-called model , or give the outlines of the figures, as the wood wears off easily, by hammering in wire pins and metal strips and filling the areas between the outlines, which should also take on color, with felt or Cloth off. Often one also works with a cast of the woodcut in stereotype metal.
The appropriately prepared fabric is spread out on a table covered with cloth, the printing form is placed on the cloth in the paint box (chassis), which must always be evenly provided with color, and then applied to the stuff. Hitting the back of the block with a wooden hammer will cause the paint to transfer to the stuff. In order to achieve the correct connection of the pattern with repeated placement of the block, there are two small pins which pierce two holes in the stuff, and the printer inserts the pin on its left side into the hole which the pin was the last time the block was placed on his right side. The paint boxes are often designed in such a way that they can simultaneously pick up several separate colors and transfer them to the block.
Instead of the wooden block, wooden rollers are also used, on which the patterns are raised in a similar manner. The printing devices with such rollers (seals), which pick up the colors from a cloth, are set in motion by machines and therefore work much faster than manual printing. Later on the roller was given up and flat printing forms were used on the Perrotine. The printing forms made of metal alloy are attached to 3-4 wooden plates, which alternately hit the stuff with moderate spring pressure after they have been fed with paint by paint rollers, while the fabric advances each time by the width of a form.
At the present time, all printing devices with raised cut patterns have been replaced by the roller printing press, in whose copper rollers the pattern is pressed. The rollers are fed with paint by other, cloth-covered rollers and freed of all paint adhering to the surface of the rollers by elastic steel cutters (doctor blades), so that only the paint adhering to the depressions forming the pattern is removed Pressure is transferred to the stuff.
Such machines are built which print 3, 4, but also 20 colors with as many rollers; but the precise regulation of the movement of all parts of such machines, by which the appearance of all colors is ensured in the correct place, is connected with great difficulties. The colors and stains to be printed on must have a certain consistency so that they adhere adequately to the form and do not run on the fabric, and are therefore mixed with a thickener such as flour , starch , dextrin , gum , tragacanth , salep , glue , pipe earth , sulfuric acid Lead oxide, etc., added.
Colorants used
In the simplest case, body colors such as ultramarine , chrome yellow , chrome green , shear wool , metal powder etc. are printed on with a binding agent such as egg white , varnish etc., and the colors are therefore attached to the fiber completely mechanically. When using egg white, the printed fabric is steamed in order to cause the egg white to coagulate and thereby fix it on the fiber. When Argentindruck fine is tin powder with ammoniacal casein printed and provided to the trowel with silver-like shine after drying, the gray metal powder.
The body colors belong to the board or application colors (topical colors), all of which are already formed and printed on the stuff. In addition to the insoluble body colors, one also uses soluble ones, which become insoluble on the fiber and thereby bond firmly to the same, so that, like the printed body colors, they withstand washing. A tin preparation is added to a redwood decoction, from which tin oxide is deposited, which is fixed on the fiber and absorbs the dye. Often the blackboard paints are attached to the fabric by the action of steam.
The witnesses are stained as in the dye works, printed with the thickened colors and then steamed, or dye and stain are applied together and a body is added which contains the colored lacquer (which the dye forms with the stain) in dissolved form or the formation of this Lacquer up to the operation of steaming prevented. The fixation takes place z. B. in such a way that acetic acid is expelled by the steaming or tin chloride is decomposed with volatilization of hydrogen chloride and precipitation of tin oxide (with which the dye combines) on the fiber. Occasionally, an oxidizing body, such as potassium chromate, etc., is added in order to achieve fixation during steaming. For the purpose of steaming, the fabric is hung up in large closed spaces in such a way that the printed areas do not touch, and high-pressure steam is introduced because the damp steam would dissolve the colors.
A lot of colors are produced in the fabric printing shop by printing the white fabric with the stain, fixing it according to the principles of dyeing, drying and then bringing the fabric into the dye liquor. The dye only precipitates on the printed areas, while the ground remains white or absorbs so little dye that it can be completely cleaned again by a soap or bran bath or by light bleaching (color bleach) (kettle colors, madder colors). But you can also impregnate the entire surface of the fabric with stain on the padding or priming machine and, after it has dried, print different colors, or you can dye the entire fabric in order to obtain a colored base on which you can print by staining and dyeing or creating patterns in other ways (block printing). The logging machine consists of two brass rollers wrapped in thick layers of cotton fabric . The fabric passes twice through a trough which contains the stain and just as often goes through the rollers, between which it is very evenly impregnated with the stain and freed from excess liquid. It is then dried as quickly and evenly as possible using special devices.
Reserve technology
Reserve technique is called an indirect dyeing process , which is used for textiles and paper, among other things. The decoration is applied with hot wax or with various paste-like substances, whereby these substances prevent the absorption of color during dip dyeing and are then removed again. As a result, the original color is retained at the covered areas, as z. B. is the case with batik and textile blueprint .
