Method and machine for treating textile materials by ammonia or other liquids

Abstract

The machine comprises: a path for the textile article (T); along the path impregnation means (11, 13) to impregnate the textile article with said product; means (23, 25) to remove the product from said textile article. The impregnation means may comprise one or more cooled rollers (11, 13) on which the product condenses and around which the textile article to be treated is driven.

Description

TECHNICAL FIELD [0001] The present invention relates to a method for treating textile materials by ammonia, in particular bolts of fabric or yarns. This type of method is commonly known as mercerization. More generally, the invention relates to a method for treating textile articles or materials by liquids at low condensation temperature. [0002] The invention also relates to a machine for treating textile materials. STATE OF THE ART [0003] Mercerization is a typical treatment for fabrics and yarns made of all cellulosic fibers, particular for cotton, which allows the material to be given a series of advantages, such as: [0004] increase in luster and hydrophilicity, [0005] increased dimensional stability, [0006] increased yield of the dye, [0007] an improvement and intensification of subsequent finishing treatments (i.e. anti-crease treatments). [0008] Currently, the mercerization process is performed with the use of alkalies, generally caustic soda, which determines: [0009] shrinkag...

AI Technical Summary

Benefits of technology

[0020] The object of the present invention is to produce a method and a machine that overcomes the drawbacks described above. More specifically, according to a first aspect, the object of the present invention is to produce a method that makes the mercerization process with ammonia simpler and less expensive, as well as intrinsically safer, and more generally a method wherein a textile article is impregnated with products that at ambient pressure condense at low temperature.

[0026] In practice, the method according to the invention to obtain condensation of the gaseous ammonia on the fabric consists in rapidly cooling the fabric, immersed in an environment saturated with gaseous ammonia, placing it in contact with surfaces maintained suitably cold with a cooling system capable of controlling the temperature. The time for which the fabric remains in contact with the cold surface and the temperature thereof allow safe and repeatable control of the percentage of impregnation of the fabric. The pressure of the ammonia gas chosen to saturate the treatment chamber, which due to incompatibility with the environment must be isolated from the outside environment, will also determine the temperature range to which the fabric must be taken to obtain condensation of the ammonia. Tests performed on various samples of linen and cotton showed that the same results are obtained both by immersing the fabric in liquid ammonia, with a degree of impregnation between 100% and 300% according to the traditional technique, and with the condensation process according to the present invention regulated in order to release variable percentages, for example between 5% and 10%, of ammonia in the fabric.

[0032] 1) the quantity of ammonia utilized during the process is considerably lower, even by 10 to 20 times compared to traditional methods, with a consequent reduction in the dimensions and costs of the drying and ammonia recovery systems;

Problems solved by technology

There are very few machines in the world that use this technology, due to the difficulties linked to the use of liquid ammonia, which at atmospheric pressure evaporates at −33° C. This makes the machines complicated to construct and causes problems related to safety and to disposal of processing waste.

As a result, the machine is very complex and costly.

The high level of toxicity of ammonia makes procedures for its recovery and liquefaction particularly complicated and critical.

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