5.3. Thermoprinting of fibrous materials

1. Simplicity

We cannot repeat often enough the simplicity of the “sublistatic” process. The fabric to be printed needs the minimum of pre-treatment (only washing and thermofixing). Calendars are simple machines and can be manned by non-specialized personnel. Space can easily be found within the finishing depart­ment for these compact machines. Absolutely no special treatment is required after printing. “Sublistatic” is a truly 100% dry process which does not require water or steam as does conventional printing.

Nothing is easier than changing the design or colorway; all that has to be done is to change the roll of paper.

2. Quality

The helio-engraving used by “sublistatic” per­mits finesse, exactitude of printing, and the use of subtle half-tones and colors unequalled by any other printing process. No better printing carrier has yet been found to better paper (it does not even deform, except, of course, under the influence of water).

The quality control checks at various stages of the manufacturing process provide another guarantee of our quality. Moreover you have a personal control when transfer printing your fabric. Your calendar transfers all the colors intact onto the fabric at one and the same time.

3. Economy

One is not confronted with problems con­cerning the availability of water or processing effluents (the prices of which continue to increase). The investments in manpower, factory space and equipment are low. The price of a transfer paper printing installation is infi­nitely cheaper than that of conventional prin­ting equipment. But it is perhaps the service offered where the principal advantages lay.

In the textile industry the imagination of the fabric designer is very restricted, the technical limitations are considerable. He must take into consideration whether the material available to him will be woven or knitted; he is restricted by the availability of the yarn counts, etc. When the designer has to take into consideration dyed yarns he will also be confronted with problems of stock, in fact, it only needs one yarn to run out of stock for the whole production to be interrupted. With the Sublistatic process the fabric, the design and its colorways are each independent of one another; one weaves or knits the fabric for transfer printing. Since one only has to stock gray cloth one reduces very con­siderably the complications of stock. The fabric designer retains full liberty in select­ing his designs and colorways as a function of the finished products and market trends. The designs that “sublistatic” have available for the requirements of every stylist are immense. The designer can see immediately the effect of a chosen design on his fabric; if the colors are not suited to his needs our colorists can create new colorways providing him with a trial length (GMS trials).

Designers who want to have a design created especially for their exclusive needs can do this by providing Sublistatic with a sketch which is then engraved. One again our colorists are ready to supply every service, with GMS trials.

Another important economy results from the almost inexistence of seconds. Second quality prints for the traditional printer represent con­siderable losses. With transfer printing such losses are almost negligible; they never exceed 2 per cent.

Regarding stock; we have already said that one stocks paper and not printed fabrics. With Sublistatic printing one is not confronted with relatively large quantities of costly printed fabrics which have to be sold at low prices towards the end of the season. One stocks unprinted fabric which can always be used for other applications. Even during the same season one can quickly respond to the demand of a client through the versatility of the process itself which allows any design to be printed on almost any synthetic fabric.

With almost negligible investment the manu­facturer who formerly restricted himself to solid shades can now add the most complicated and finely printed fantasy designs to his collection without difficulty.

Thermoprinting of fibrous materials is based on ability of some dyes evaporate (sublimate) at the raised temperature. (Sublimation - transition from a firm condition in gaseous passing a liquid phase).

Technologically this process develops of two operations:

1. Printing drawings on a paper сублимирующимися dyes.

2. Transfer of drawings from a paper on a fibrous material.

To a paper used in thermoprinting, a number of specific requirements is shown: it should be smooth, have uniform density, to be enough strong in a wet condition, to keep as the smaller quantity of dye is possible, without interfering with its transition in a fibrous material while translating drawing.

Sublimatics properties many disperse dyes, and also some cationic, acid and cube possess.

Drawings are put on a paper or on polygraphic (use a way of a flexography, offset printing, a way of an intaglio printing), or on textile (apply the press by cars with cylindrical mesh templates) the enterprises. For the press on a paper printing paints prepare on special and usual thickeners.. Most often applied thickeners: white-spirit, solvitoza С-5, manutex RS, the dye maintenance in a printing paint of an order 200g/kg.

Transfer of drawings from a paper on a fibrous material is carried out on the equipment of two types: flat press and calendars. The last - more productive and widely used kind of the equipment.

Fig.5.1. The basic scheme translation calendar.

1 - heatable the cylinder; 2 - rollers with a paper; 3 - rollers with a printed fibrous material (a knitted cloth, Fabric, nonwoven material); 4 - infinite cloth.

While translating drawing there is a sublimation of dye from a paper surface, its transition through a gas phase (an air backlash between a paper and textile fiber a material), its condensation on a surface of a fibrous material, dye diffusion deep into fibers and its fixing in it. Necessity for the subsequent steam and washing disappears.

The paper with the put drawing is used for thermoprinting only once. A paper waste goes for repeated processing.

Thermoprinting of fibrous materials during the last years gets the increasing popularly in world practice. Order of performance of work.

1. Samples polyester and acetate knitted cloths are cut out, cotton fabrics and papers with the put drawing in the size 3x8 sm.

2. On samples of fibrous materials the paper is imposed.

3. Transfer of drawing from a paper on fibrous materials by means of a clip of an electric iron, нагретого to 210°C with within 2 minutes is made.

By results of work to draw a conclusion on suitability of the given way for the press of fabrics of various fibrous structure.

To put to the report the printed fibrous materials and samples of a paper after the press.