WO2002063094A1

WO2002063094A1 - Yarn dyeing process by inkjet system

Info

Publication number: WO2002063094A1
Application number: PCT/IT2002/000045
Authority: WO
Inventors: Pasquale Mario Rotonda
Original assignee: Linea Tessile Srl
Priority date: 2001-02-08
Filing date: 2002-01-30
Publication date: 2002-08-15
Also published as: EP1360368A1; ITMC20010012A1

Abstract

This invention refers to a polyvalent process for dyeing textile yarns of different nature, by means of a system which uses inkjet printing heads, appropriately modified and equipped by one or more holes, aligned longitudinally, with the yarn running along below them. With this process one obtains a very fine dispersion of pigments in liquid (the composition of these will vary according to the type of fibre), sufficient to dye the yarn. There are considerable advantages regarding energy-savings, installations, environment pollution, timing, storage in stock, etc.

Description

I

DESCRTPTTON

YARN DYEING PROCESS BY INKJET SYSTEM

Technical field:

This invention refers to the process of dyeing textile yarns, by means of a system, which uses inkjet printing heads, appropriately modified.

As it is known, sometimes the textile industry modifies the appearance of the yarn itself, colouring it as requested by the working in course. Background art:

The dyestuffs used during the dyeing process are very closely linked to the characteristics of the single fibres; initially dyestuffs of only animal and vegetal origin were used. Nowadays the dyestuffs used are prevailingly of artificial origin (for example obtained by synthesis of tar).

For the dyeing of yarns modern installations are able to execute the operation on the prime material made up in various ways, hanks, cones, spools. The dyeing process consists in a balance of the distribution of the dyestuff between fibre and dyeing-bath; it is executed in appropriate boilers in copper, iron or stainless steel, in which the dyeing liquid is put. In many cases the dyeing liquid is kept in forced circulation by pumps. At the beginning of the process the dyestuff is located in the bath, then it starts to migrate towards the fibre, spreading inside until the fibre enriched by the dyestuff, can start to return part of .it to the bath. The process is terminated when the dyeing molecules, which are migrating from the bath towards the fibre, are equivalent to the ones which are moving towards the bath. The remaining dyestuff left in the boilers is expelled and put into appropriate containers for purification. This process requires long production times, high costs of installation and management of the plants, being them of considerable dimensions, having an elevated energy-consumption, (the bath must be brought to high temperatures), but, above all, being extremely polluting. Given that high quantities of water are used during the dyeing processes in the textile industry, consequently the development of recycling or demolition of the emissions is appropriate. It is important for the textile industry to introduce dyeing processes, which are productive and integrated in a more efficient way, less expensive, less risky and more respectful of the environment, or processes for the treatment of the waste regarding the recycling of the water.

In fact, the waste waters of the textile industry can include many types of dyestuff, detergents, insecticides, pesticides, grease, oil, solvents, etc. in quantities depending upon the working conditions. The resistance and the bio-toxicity of many of these components of the waste waters and their variable concentration, show how existing treatment systems are very expensive and polluting. The working water has to respect very strict quality standards and this, together with the difficulties of treatment, makes the implementation of the process of re-utilization of the water very difficult. Although recently new dyestuffs have been developed, some of which with a high biodegradability, the textile industry is still one of the most important and heavy causes of pollution. Disclosure of invention:

The aim of the present invention is to define a polyvalent process for the dyeing of fibres of different nature, from cotton to linen, to viscose, to silk, to wool, to artificial fibres (like polyester and other), and with different types of colouring, exploiting rationally the use of the inkjet system.

Another aim is to define a process of colouring yarns, which can allow economic advantages, contributing to a higher competitiveness of the textile industry, decreasing this way the production costs, decreasing the pollution, avoiding the use of machines of enormous dimensions, of high costs and high energy waste.

Another aim is to define a process of colouring yarns, which disposes of suitable ways to avoid environment pollution.

Another aim is to define a process of colouring yarns, which disposes of suitable ways to allow a reduction of the time needed to obtain the goal of the process.

These and other aims will appear achieved by the reading of the following detailed description, explaining a new process of colouring yarns, applicable in the sector of dyeing houses for yarn colouring, having the peculiarity of applying . a colouring, similar to the one commonly used today for the so called inkjet printers, containing, instead of the normal ink, a suitable ink for yarn colouring. Best mode for carrying out the invention:

The implement will be made of a programmable printing head, equipped by one or more holes, aligned longitudinally, allowing a very fine dispersion of pigments in liquid, sufficient to dye the yarn.

Its composition will vary according to the type of yarn to colour. In series one could also foresee a fixation system of the colour. For the process, an instrument will be used which allows the yarn to run along continuously, placed directly under the holes, from where the

85 colour is issued. The printing head will be appropriately adapted to inject the colour onto the yarn. The process will be guided by a computer, which will make it possible to program the running speed of the yarn and the quantity of colour strictly necessary to dye the yarn. It will also be possible to vary the colouring of a yarn without

90 interrupting its running along or changing the hank.

The intimate essence of the invention is exactly to be able to inoculate dyestuff from a printing head made of one or more aligned holes, of variable, but anyway small, dimensions, onto a yarn running along longitudinally below it. In this way the drop of

95 dyestuff is wrapping the yarn and dyeing it quickly. For yarns with more filaments the process obtains better results because the attraction force between dyestuff and yarn increases. In fact, increasing the surface, the capillarity force increases too. The materials necessary for the process are textile inks, very similar

100 to the dyestuffs in use, but appropriately adapted and filtered in order to obtain a higher pureness to allow the printing heads to handle them.

The composition of the ink will have to be studied in order to adapt it to the characteristics of the single fibres, just like it happens

105 nowadays for the traditional baths.

The process of dyeing requires . in fact different dyestuffs depending on whether one is dyeing cotton, wool, artificial fibres, linen and hemp, silk, mixed yarns. In any case, the yarn will have to be treated by a purifying process,

1 10 being this different for each type of fibre. After dyeing, a quick system (for example heating) for the fixation of the ink onto the yarn will have to be studied anyhow. With this process it will be possible for example to eliminate the mechanisms of changing colour in embroidery and weaving machines.

Brief description of drawings:

The invention of the process is illustrated, in an exemplified, but not restrictive way, in the attached drawings, where:

- FIG. 1 illustrates the process seen from the front. - FIG. 2 is a view of the printing head in profile.

- FIG. 3 is a view of the process from above.

Referring to the mentioned drawings, the process indicated globally with reference number (1), is made up of an inkjet printing head (2) equipped by holes (3), which issue the dyeing liquid (4), which strikes the yarn (5).

Industrial applicability:

In practice it has been ascertained how the process accomplishes fully the pre-established task, because it doesn't require the use of costly and polluting machinery and can be adopted in order to obtain the colouring of yarns in a short time.

In practice, the used materials and their dimensions can be different, depending on the needs and the, status of the technique.

Claims

1) Yarn dyeing process by inkjet printing heads, characterised in 135 that it contains a printing head equipped by one or more holes, which inject the dyestuff and colour the yarn which is running along below them.

2) Yarn dyeing process by inkjet printing heads, as claimed in claim 1, characterised in that it is applicable to all types of yarn: cotton,

140 linen, silk, viscose, wool, artificial fibres, mixed yarns.

3) Yarn dyeing process by inkjet printing heads, as claimed in the preceding claims, characterised in that it allows advantages in terms of economy and time, which will contribute to increase the competitiveness of the textile industry.

145 4) Yarn dyeing process by inkjet printing heads, as claimed in the preceding claims, characterised in that it reduces the environmental pollution.

5) Yarn dyeing process by. inkjet printing heads, as claimed in the preceding claims, characterised . in that one can control, by a

150 computer connection, the issuing of the dyestuff, varying the quantity of liquid to inject and the type of colour, according to needs, by different holes with which the printing head can be equipped.

6) Yarn dyeing process by inkjet printing heads, as claimed in the 155 preceding claims, characterised in that the same yarn can be coloured with different colours, in a way that: a) a special fashion-effect can be given, b) the change of colour can be made without cutting the yarn, so to eliminate the tools which make the colour change,

160 c) big stocks of yarn in different colours can be avoided, because in this way the yarn is coloured when and where needed.