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Digital Processes for the Future       ( First patented 22.09.2003)

1024338 22.09.2003 NL PCT/NL03/00841 28.11.2003 NL Title: METHOD AND DEVICE FOR DIGITALLY COATING

Inventor: CRAAMER, J.,A. 

 

The textile industry is composed of a wide number of sub-sectors, covering the entire production chain from the production of raw materials (man-made fibres) to semi-processed (yarn, woven and knitting fabrics and their finishing processes) and the final products (carpets, home textile, clothing and industrial use (textiles). Within this production chain, the textile finishing processes have inevitably a significant impact on the environment. Dyeing, printing, coating and finishing processes involve one or more of the following unit operations: (wet) impregnation: applying chemicals into or onto the substrate; reaction/fixation: chemically binding the chemicals to the substrate;-washing/rinsing: removal of the excess chemicals with water; - drying: evaporation of water absorbed in the textile substrate.The sequence and the number of unit operations are very variable and dependent on the requirements of the final user of the finished substrate. All unit operations however have a significant environmental impact. Environmental issues are: consumption of (hazardous) chemicals and water;water discharge and chemical load it carries; energy consumption; air emissions; solid wastes and odours. Although a lot of effort has been made, the unit operations and the process equipment applied have not fundamentally been changed in the last 50 years or so. Main environmental benefits realised so far are in most cases the result of good anagement practices introduced, quality management of incoming fibre, smart selection and substitution of chemicals used and to a minor extend technological improvements in process equipment. In this project I will implement and demonstrate a high speed industrial digital finishing technology that can replace (a major) part of the traditional dyeing, coating and finishing operations as is, leading to a significant reduction of environmental impact and at same time an improved economical performance due to increased production flexibility, shorter runtimes and significantly less consumption of chemicals, water and energy. The process to be demonstrated is based upon the principle of an ink-jet system that has been made suitable for not only printing, but also dyeing, coating and finishing operations. Contrary to the current ink jet systems available, that are only suitable for printing, the technology to be demonstrated in this project can operate at high industrial production speeds, processing up to 20 meters of substrate each minute. Existing digital textile ink-jet printers operate at maximum performance speeds of about 100 -150 m2 an hour (that is approximately 2 -2.5 meters per minute). The relatively low achievable performance speeds of existing digital textile ink-jet printing machines limits the economic attractiveness of these machines to runs with maximum lengths of 100 to 200 meter (see also BREF for Textile Industries - chapter 4, page 372 - this document states that speeds are even limited to a maximum of 40 m2/h). Also the application of these existing machines is limited to printing only. The machine to be demonstrated in this project however will be utilized for dyeing , coating and finishing operations.

The traditional finishing process As mentioned above, the traditional finishing operations are involving a number of unit operations. As it is usually not possible to realise the desired result (colour intensity, waterproof effect, etc.) in/on the substrate by running it trough one series of unit operations the finishing operations are mostly performed in one or more cycles. These standard processes are not very selective and

overdoses of chemicals are required to bring about the wanted result. To transport these chemicals

to the fibre of the substrate, at which it should be reacting, water is used as a transport and dilution/dispersion medium. For batch as well as for (semi-)continuous operations this results in a significant production of hard to treat (often poor biodegradability) waste water and the consumption of significant amounts of energy for drying the substrate. In this case it should be noted that drying is not only a last step treatment, but often for different finishing steps drying is required (as dry substrate is required for the previous as well as following finishing operation). This means that a final finished cloth sometimes has undergone three or more washing and drying steps. The digital finishing process to be demonstrated The high speed digital finishing technology to be demonstrated consists of a series of sequential ink- jet beams located above a moving textile substrate to be finished. The fixed position of the ink-jet heads above the substrate, in stead of one head moving alongside the beam, offers the potential for a high speed continuous operation and substrate transport. A sequence of beams equipped with ink-jet heads offers the potential for dyeing, coating and finishing in case a number of sequential beams are running with digitally spray-able dyes, coatings or finishes. The number of beams utilized and the nozzle size, drop frequency (50 - 85 kHz) and speed of the substrate determines the amount of chemical that can be applied. In principle with an eight beam-machine dyeing (1-2 beams), coating (2-4 beams) and finishing (2-4 beams) operations can be performed in one machine run. The digital execution of the finish operations results in a significant reduction in the consumption of chemicals (almost no excess of chemical is required), water (no water bared chemical batches are required) and energy (reduced water load of substrate). This subsequently results in significantly less polluted water discharge. SUMMARY OF THE PROJECT Project title : Digital printing/dyeing, coating and finishing with Continuous High Speed Ink-Jet technology, significantly improving sustainability, flexibility and economic performance of textile finishing industry Objectives The objective of this project is to emonstrate the new (ink)jet based digital finishing technology and its associated environmental benefits and economic viability and to disseminate the project results and the potential of the technology to relevant target groups. It will be demonstrated that digital finishing of textile substrate: can be performed at industrial speeds approx. 20-100 m/min requires significantly less water, energy and chemicals to achieve desired finish-results results in significantly less spillage of fabric (no start-up meters) produces the same or better finish-quality as textiles produced with traditional methods is very flexible in its operation can replace approx. 50 - 70% of traditional finishing operations Actions and means involved In this project the continuous high speed ink-jet technology will be demonstrated full-scale, this will show that this new technology is suitable for industrial use and that it can replace 50-70% of the traditional finishing operations, with a significant improvement of the nvironmental impact. The fixed position of the ink-jet heads above the substrate, in stead of one head moving alongside the beam, enables high speed operation and substrate transport. The project will show that digital finishing technology is a good alternative for a major part of the traditional finishing ethods. Results will be isseminated to a broad audience.Expected results Demonstration of an innovative and economical viable solution that compared to traditional finishing technology: Improves environmental performance by reducing: water usage -70-80% energy usage -70-80% chemical usage -50% waste water -70-80% production solid waste -50-70%. Improves economical performance as a result of: industrial finishing speeds of 20-100 m/min and more high flexibility for substrates, run-lengths, type and order of finish operations, etc. With a typical annual production of 6.000.000 meters of substrate and a typical product mix for dyeing, coating and finishing (for operations that can be replaced) realistic reductions possible are: water usage: 16.800 m³/yr energy usage: 26.000 MWh/yr chemicals for dyeing: 47.000 kg/yr chemicals for coating/finishing: 69.000 kg/yr secondary chemicals: 57.000 kg/yr waste water: 12.000 m³/yr solid wastes: 90.000 kg/yr  Reproduction potential and transferability With a turnover in the EU of€ 198 billion created at 114.000 companies with about 2.2 million employees (year 2000 figures) the EU textile industry represents approximately 3.5% of EU manufacturing and 7% of industrial employment. The textile sector therefore is a sector of ajor importance to the socio-economic position of the EU. The re-production potential of the technology demonstrated in this project can be found within the textile finishing industry, a sub-sector of the textile industry. The total turnover of the textile finishing industry amounts in 2000 nearly €11 billion and this sub-sector employs more than 117.000 employees. The majority of the EU textile  finishing companies are SMEs. The share of the main type of fibres used in the textile finishing industry is :cotton 45% wool 8% polyester 14% acrylic 2% others 15% The technology will demonstrate in this project covers in principle all finishing operations where chemicals are applied to the textile substrate (that is dyeing, coating and finishing). These chemicals however have to be (made) jet-able for continuous jet-flow application before they can be applied in this digital process (this means right dilution or dispersion with specified particle size distribution and electrical chargeable -for this an extra agent might have to be applied). In this demonstration project the emphasis will be on digital finishing of polyester/cotton. These are the main fabric processes and they are considered to be most relevant (on the short term) for digital operation. Also for these fabric/chemical combinations.The polyester/cotton fabrics represent a major part (59%) of the fibres used within the EU finishing industry. Therefore the direct reproduction potential can be considered to be very significant.Not all substrate/chemical combinations can be processed with the digital finishing system. Some chemicals cannot be made jet-able, for instance due to particle size that result in blockage of the nozzles or due to crystallization of salts present in the chemical dilution. In this last situation an impregnation of the substrate with the salt up-front to digital processing will possibly be a good digital processing route. Research performed until now shows that a major part of chemicals used for finishing polyester/cotton substrate can be made jet-able. The textile finishing industry is a very capital intensive industry. For a broad range of finishing operations a broad range of installations are available that operate in batch, semi-continuous and continuous modes. Installations that are present in most finishing plants are for fabric in rope form: Winch beck, Jet, Overflow, Soft-flow and Airflow. For fabric in open-with one or more of the following machines are present: Beam, Jigger (both batch), Pad-batch, Pad-roll, Pad-jig, Pad-steam, Pad-dry and Thermosol. Due to its flexible operation (low system content and cip-system makes shift of operation easy and fast - no complex cleaning operations - no lead times and no product loss for run-in operation due to very good control of amount of chemical to be applied and distribution of dots over substrate surface) the digital finishing technology to be demonstrated in this project will be able to replace a major part of the utilization of these batch as well as (semi- )continuous machines and will lead to a significant reduction of the environmental impact associated to the use of these machines. Due to its high (industrial) speed of about 20-100 m/min and the ease and short times for shift in operation modes the digital finishing machine can economically process textiles substrate lengths between 50 m to virtually thousands of meters. The eight sequential jet beams each followed by a drying beam offers in potential the possibility to perform eight different finishing operations on a textile substrate in one machine-run. Intermediate drying (by means of infrared or other) supports drying and fixation in case "wet-in-wet" application is not feasible. However in most cases for the realisation of a good colour effect (in case of dyeing) or a significant layer thickness (in case of coating) two or more beams will be applying the same chemical. So in principle with an eight beam-machine dyeing (4 beams), coating (2-4 beams) and finishing (2-4 beams) operations can be performed in one machine run at speeds of 20-100 m/min.Environmental  problem Digitalizing the finishing process means that the dyeing, coating and finishjng can be applied with ink- jet technology with high precision, preventing "run-ins" that require a lot of substrate and chemical and lead to spillage, limiting the amount of chemical to be used due to the fact that almost all chemical will be applied to the substrate, limiting water consumption and waste water production due to fact that no baths are required and limiting energy consumption due to less water use and therefore less drying needs. Water consumption: in traditional finishing almost every operation where chemicals are applied to the substrate works with very watery chemical dilutions/dispersions. Water is the medium to transport the chemical to the fibre. In the digital process a concentrated chemical dilution is directly applied (jetted) on the substrate/fibre in the right dosage. Traditional finishing also involves a number of washing steps removing the excess of chemical. In digital finishing no or in some cases one washing step will be required. Energy consumption: between traditional processing cycles (mostly after washing but also after other wet applications) drying of the substrate takes place. In most cases the water is first mechanically forced out of the substrate, and then the substrate is thermally dried by evaporation of water. Also energy is consumed due to higher temperature application of chemicals (warm dye bath). Due to the low water content of the chemicals applied in digital operation and the fact that these chemicals are applied at room temperature significant energy consumption reductions will be realised. Also the less mechanical handling will reduce electricity consumption. Chemical usage: precise chemical dosage trough jetting of dots, no prepared baths with excess chemical to be used, lower pressure and less adsorption in the substrate-fibre all leads to less chemical consumption with digital operation compared to traditional (especially batch) operation. Not only primary chemicals will be saved, but also the utilization of secondary chemicals such as salts will be reduced. Waste water production: in traditional finishing operation most of the process water (from chemical baths, steam fixation and from washing and cleaning of equipment) will be discharged after application. These waste water streams will contain chemicals or residuals from chemicals. Since in digital finishing no baths are applied, the total water consumption is very low and the substrate is not saturated with water after treatment the waste water production is limited. The only significant discharge might be associated with the one washing step that sometimes is required after digital finishing. Due to very low system-content cleaning of the digital ink-jet system is water free and mostly the new chemical to be applied will be used leading to no or very low spillage. Solid waste production: due to high very good controllable quality (amounts to be applied) losses of finished substrate due to non-onformance will be almost zero. Also run-in operation to realise a table situation is not required. The traditional process route could be: dyeing - washing - drying - coating (two passages) - drying/curing - finishing (1 passage) and drying. In the digital process six jet-beams are utilized for dyeing (3 beams), coating (2 beams) and finishing (1beam) and after each treatment an integrated drying/fixation step (infrared drying with drying beams – chemicals within one finishing operation are applied "wet-in-wet"). Value for money: environmental cost/benefit ratio Value for money: With the new high speed digital finishing technology the full potential of digital operation from an economic as well as from an environmental point of view comes into reach. Relevant aspects determining the value for money of the proposed technology/solution are: - high speed digital ink-jet operation: for this "DSDS" will be used. This machine-lay out will enable speeds up to 20-100 m/min. - at these high speeds not only printing will be achieved (as in existing digital textile printers that operate at speeds up to 3 m/min) but also dyeing (full-font printing), coating and finishing will be possible. This is completely new and has only become feasible due to development of special chemical recipes (very fine and narrow defined particle size distributions and electrical chargeable solutions/dispersions) for digital processing and the adaptation of the nozzles size to the maximum

molecule size. - high speed drying and fixation: due to low water content of substrate (only water used to dilute

chemicals or to create a stable and jet-able dispersion needs to be evaporated) water evaporation during drying (possibly infra red or in the future ultraviolet with dedicated chemicals) is low, thus involves a very low energy consumption. - flexible operation: low system content and cip-system makes shift of operation easy and fast, no lead times and product loss for run-in operation (controlled distribution of dots over substrate 

surface). These aspects form the basis for the economical as well as the environmental potential of this

technology. When looking at the position of the textile industry and its development in the international arena it is clear that especially high tech textile applications are the future.High speed production with relatively low environmental impact can go alongside with small orders/runs for highly specialised textile products for advanced applications and just-in-time production/delivery.This is the future for the textile industry and for a major part of the textile finishing industry as figures over recent years show almost only growth in the technical/advanced textile segment. The technology certainly also has potential for the garment textile segment. When combined with currently ongoing technological developments in the garment textile industry

 the technology can contribute to a simplification of the production chain and a significant reduction of production times from raw textile substrate to ready to wear clothing. This opens potential for just-in-time production/delivery and flexible design/dessin on demand in this production chain, preventing over-production and over-stocking at trade and selling points. In this way the close location of the industry to its market again becomes a strength. From a value for money point of view digital finishing offers compared to traditional finishing techniques:  . 1. lower or equal capital cost (especially for future systems due to learning curve effects lower capital cost are expected) 2. significantly lower operational costs (due to utilization of less chemical, water and energy and expected reduction in substrate loss) 3. significantly increased production

flexibility 4. significantly decreased process times .Environmental cost/benefit ratio: for a production of 6 min meters of substrate and a given product-mix the environmental benefits and related financial savings have been calculated comparing traditional to digital finishing. The pay-back time of the investment on environment related savings is estimated to be 7 years. Other strengths, like increased production flexibility and reduced production times, will further improve economical pay-back. Added value of international approach and employment implications Employment implications It is expected that the implementation of the digital finishing technology in this project will directly and indirectly lead to the creation of employment. In the first place the implementation and investment will lead to extra employment for machine operators (at least 3 fte) and a process  engineer (1 fte). As a spin-off of this project and due to expected follow-up implementations of digital finishing process lines at other textile finishing companies it is expected that as a result of increasing orders the employment at subcontractors and other firms developing, building and marketing digital ink-jet machines for textile applications will grow. This new digital finishing technology will enable cheaper production of high-end textiles, more flexible production (planning), and faster logistics of the whole process. This can give the textile finishing industry competitive advantage in the global textile market. And last but not least the implementation and utilization of digital finishing technology can strengthen the position of textile (finishing) industry with conservation and possible creation of employment as a result. This is especially expected in the domain for high-tech textiles where this new technology can give companies a significant competitive advantage due to reduced production costs, improved production flexibility and reduced production times. Social benefits and acceptance. The project contributes to improvement of sustainability and indirectly also to an improved sustainability and awareness of the textile industry. This contributes positively to the social acceptance of the industry. The high tech digital finishing technology can also improve attractiveness of EU textile industry and therefore improve the possibility to attract new, young and highly qualified personnel (improve human capital). This might give an important and significant impulse to a sector that mainly consists of SMEs and has a relative old employee population. The digital revolution in the textile finishing sector starts now!                                                                                     {4 oktober 2007}

Imparting color to a textile is a process to decorate it. Color is the visible part of the Electromagnetic Spectrum (400 nm - 700 nm) The color can be created by colored or none colored chemical substances in a full plane or particial, visible or not visible on one side or both sides of the textile. There are also processes to improve the quality of textiles to make them appealing to the consumer. This improvement of quality can be created by chemical substances in a full plane or particial  visible or not visible on one side or both sides of the textile. Textile is any filament, fiber, or yarn that can be made into fabric or cloth, and the resulting material itself. <BR>The fabric  can be woven, knitted, tufted or non woven. The consumption of energy in the form of electricity and water is relatively high in the textile industry, specially in the pre-treatment, dyeing, coating and finishing divisions. Approx. 25 % of energy of the total textile production like, fiber production, spinning, twisting, weaving, knitting, clothing manufacturing etc. is used for dyeing. It is very important to advance energy and water  conservation in the pre-treatment, dyeing, printing, coating and finishing field. The dyeing and finishing process generally goes through repeated wet and dry operations. The development and utilization of process-specific techniques is very important. According to all known  process possibilities, we propose for example a modem factory  wherein all wet processes, like pre-treatment, dyeing, printing, coating and finishing are done continuous, in the full width up to 500 centimeters, with velocities up to 100 meters/minute. We will call it  DSDS-System. With the DSDS-System you can use the dyestuffs and chemicals which are used in the traditional textile pre-treatment, dyeing, printing, coating and finishing  processes.

The production rationalization, as time-saving, labor-saving, energy saving, water/waste water reduction, space saving with the DSDS-system could be between 70-90 %.

IPublication Number: WO/2005/028729 International Application No.: PCT/EP2004/010731 Publication Date: 31.03.2005 International Filing Date: 22.09.2004 Int. Class.: B41J 11/00 (2006.01), B41J 3/407 (2006.01), B41J 3/54 (2006.01), B41J 3/60 (2006.01), D06B 11/00 (2006.01) Applicants: TEN CATE ADVANCED TEXTILES B.V. [NL/NL]; Campbellweg 30, NL-7443 PV Nijverdal (NL) (All Except US). CRAAMER, J.,A. [NL/NL]; De Kampen 48, NL-6943 HE Meppel (NL) (US Only). Inventor: CRAAMER, J.,A. [NL/NL]; De Kampen 48, NL-6943 HE Meppel (NL). Agent: CLARKSON, Paul; Howrey Simon Arnold & White, CityPoint, One Ropemaker Street, London EC2Y 9HS (GB). Priority Data: 1024338 22.09.2003 NL PCT/NL03/00841 28.11.2003 NL Title: METHOD AND DEVICE FOR DIGITALLY COATING TEXTILE Abstract: A method is disclosed for digitally forming a coating on a fibrous textile (100) having mesh openings (106) between adjacent fibres (104). According to the method, textile (100) is fed continuously along a treatment path having a row of static coating nozzles (12) arranged generally transversely across the path. The coating nozzles (12) have outlet diameters of greater than about 70 microns and are supplied with a supply of a coating substance. By individually controlling the nozzles (12), a substantially continuous stream of droplets of the coating substance is produced and selectively directed onto the textile (100) to form a coating of pixels (102). Each pixel (102) covers at least four mesh openings (106) and has a diameter of more than 100 microns. Designated States: AE, AG, AL, AM, AT, AU, AZ, BA, BB, BG, BR, BW, BY, BZ, CA, CH, CN, CO, CR, CU, CZ, DE, DK, DM, DZ, EC, EE, EG, ES, FI, GB, GD, GE, GH, GM, HR, HU, ID, IL, IN, IS, JP, KE, KG, KP, KR, KZ, LC, LK, LR, LS, LT, LU, LV, MA, MD, MG, MK, MN, MW, MX, MZ, NA, NI, NO, NZ, OM, PG, PH, PL, PT, RO, RU, SC, SD, SE, SG, SK, SL, SY, TJ, TM, TN, TR, TT, TZ, UA, UG, US, UZ, VC, VN, YU, ZA, ZM, ZW. African Regional Intellectual Property Org. (ARIPO) (BW, GH, GM, KE, LS, MW, MZ, NA, SD, SL, SZ, TZ, UG, ZM, ZW) Eurasian Patent Organization (EAPO) (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM) European Patent Office (EPO) (AT, BE, BG, CH, CY, CZ, DE, DK, EE, ES, FI, FR, GB, GR, HU, IE, IT, LU, MC, NL, PL, PT, RO, SE, SI, SK, TR) African Intellectual Property Organization (OAPI) (BF, BJ, CF, CG, CI, CM, GA, GN, GQ, GW, ML, MR, NE, SN, TD, TG). Publication Language: English (EN) Filing Language: English (EN)

DESCRIPTION
METHOD AND DEVICE FOR DIGITALLY COATING TEXTILE The present application claims priority from Dutch application number 1024335 filed on 22nd September 2003 and also from PCT applicationNo PCT/NL03/00841 filed on 28th November 2003, the contents of which are hereby incorporated by reference in their entirety. The present invention relates to a device for digitally coating textile. In particular, it relates to a device for coating a textile using a continuous flow inkjet technique to provide accurate coating characteristics. It furthermore relates to a method of coating textiles using such a technique and to the textile produced thereby. Coating is one of the operations frequently performed during the production of textiles. Roughly five stages can be distinguished in such production; the fibre production; spinning of the fibres; the manufacture of cloth (for instance woven or knitted fabrics, tufted material or felt and non-woven materials); the upgrading of the cloth; and the production or manufacture of end products. Textile upgrading covers a number of operations such as preparing, bleaching, optically whitening, colouring (painting and/or printing), coating and finishing. These operations generally have the purpose of giving the textile the appearance and physical characteristics that are desired by the user. Coating of the textile is one of the more important techniques of upgrading and may be used to impart various specific characteristics to the resulting product. It may be used for making the substrate fireproof or flameproof, water-repellent and/or oil repellent, non-creasing, shrink-proof, rot-proof, non-sliding, fold-retaining and/or antistatic. Conventional processes for upgrading textile are composed of (figure 1) a number of part- processes or upgrading steps, i. e. pre-treating the textile article (also referred to as the substrate), painting the substrate, coating the substrate, finishing the substrate and the post-treatment of the substrate. The usual techniques for applying a coating on solvent or water basis are the so-called knife-over-roller, the dip and the reverse roller coaters. A dispersion of a polymer substance in water is usually applied to the cloth and excess coating is then scraped off with a doctor knife. Certain characteristics are difficult to achieve using such conventional coating techniques and must be attained by other techniques. In order to provide a full colour to the article, painting may take place by immersing the textile article in a paint bath, whereby the textile is provided on both sides with a coloured substance. For other effects, foularding. (impregnating and pressing) may be used. Each of the upgrading steps shown in figure 1 consists of a number of operations. Different treatments with different types of chemicals are required, depending on the nature of the substrate and desired end result. For the upgrading steps of printing, painting, coating and finishing four recurring steps can generally be distinguished which often take place in the same sequence. These treatments are referred to in the professional field as unit operations. These are the treatments of impregnation (i. e. application or introduction of chemicals), reaction/fixing (i. e. binding chemicals to the substrate), washing (i. e. removing excess chemicals and auxiliary chemicals) and drying. These unit operations may also need to be repeated a number of times for each upgrading step e. g. repeated washing cycles. Large quantities of chemical reagents and water are generally used which entails a relatively high environmental impact, a long throughput time and relatively high production costs. It is moreover usual at present to carry out the different upgrading steps of the textile in separate devices. This means that for instance the painting is performed in a number of paint baths specially suited for the purpose, the printing and coating are carried out in separate printing devices and coating machines, while finishing is carried out by yet another device. Because the different operations are carried out individually in separate devices, the treating of the textile requires a relatively large area, usually spread over different room areas. It is thus desirable to provide methods of upgrading, i. e. painting, coating and finishing, a substrate of textile where the above stated drawbacks and other drawbacks associated with conventional processes are reduced. Various attempts have been made to use inkjet printing techniques for performing. upgrading steps. In particular, inkjet printers have been suggested for printing an image onto a textile. Conventional inkjet techniques known for printing onto paper media have however been found difficult to implement for textile production where textile widths of more than 1 meter are standard and production speeds of 20 meters per minute or more are required in order for the process to be efficient. In particular, conventional inkjet printers comprise a printing head that moves backwards and forwards across the medium. The printing head has a number of nozzles through which streams of ink droplets may be fired. These print heads operate according to the dot-on-demand principle i. e. they are electronically controlled to deposit an ink droplet or not according to the image to be printed. The medium is fed forwards intermittently after each pass of the printing head. Both the intermittent feed and the drop-on-demand control cause the process to be too slow for practical use. Feed velocities of 2 meters per minute are currently achievable using such methods for textile printing. A process is known from United States patent No. US 4,702, 742 in which a conventional printing device is used to print onto white cloth sheets. A further process is suggested in German patent application No. DE 199 30 866 in which both ink and a fixing solution are applied to a textile using a conventional inkj et head. In particular, it has been found that conventional inkjet printing devices are unsuitable for the purpose of coating textiles. This is particularly the case when used on fibrous textiles in which gaps exists between the adjacent fibres, especially for coarsely woven or knitted textiles. Typical nozzle diameters used in conventional inkjet devices are relatively small in order to provide fine pixel definition. It has been found that the droplets produced by such nozzles tend to pass into or even through the gaps providing a less than adequate surface finish. It has also been found that despite the advantages of printing onto textile using inkjet techniques, pixel definition of images produced on coarse textiles is often deficient due to the coarseness of the fibre structure and other effects such as wicking which may not be homogenous in all directions. According to the invention there is provided a method of digitally forming a coating on a fibrous textile having mesh openings between adjacent fibres, wherein the method comprises continuously feeding the textile along a treatment path having a row of static coating nozzles arranged generally transversely across the path, the coating nozzles having outlet diameters of greater than about 70 microns, supplying the nozzles with a supply of a coating substance, individually controlling the nozzles to provide a substantially continuous stream of droplets of the coating substance and selectively directing the individual droplets to impinge on the textile to form a coating of pixels lying generally on the surface of the textile, each pixel covering at least four mesh openings and having a diameter of more than 100 microns. In this way, by using a larger nozzle and producing a droplet of sufficient size to cover four mesh openings, the droplet is adequately supported and spread or flattened across the textile surface. In the present context, the pixel formed by the droplet is considered to lie generally on the surface but may also enter the gaps between the fibres and may also partially surround the fibre at least on the side of the one surface in order to form an adequate bond therewith. The method is particularly applicable to woven or knitted textiles. Preferably, the method further comprises feeding the textile along a second row of static nozzles also arranged generally transversely across the path, supplying the second row of nozzles with a supply of a second substance and individually controlling the nozzles to provide a substantially continuous stream of droplets of the second substance to the textile. The second row of nozzles may be used for another distinct upgrading step. In particular they may be used for printing, painting or dying the fabric. In particular, the second row may comprise nozzles having outlet diameters of less than 50 microns to produce a finer pixel definition. In an exemplary embodiment, high definition inkjet printing may be performed onto the coating after the textile has passed the first row of nozzles. Alternatively, the second substance may be applied prior to the coating substance. In this case, it may e. g. be received and absorbed within the fibrous structure and the coating may form a protective layer thereover. In another embodiment of the invention, the second row of nozzles may be provided on the opposite side of the treatment path from the first row of nozzles. In this case, the second row may be substantially similar to the first row and the method may comprise applying the coating on both surfaces of the textile. Alternatively, the second row may be used to apply a different substance to the second surface of the textile whereby the finished textile exhibits different characteristics on each surface. Further rows of nozzles may be provided according to the treatments required. It has been found extremely advantageous to use nozzles of the continuous inkjet multi- level deflection type. The method may thus comprise electrically charging or discharging the droplets, applying an electric field, and varying the electric field so as to deflect droplets such that they are individual deposited at suitable positions on the textile. In this way the precise position of each pixel may be carefully controlled e. g. the degree of overlap or the spacing therebetween. Using such techniques, each nozzle may generate as many as 100,000 droplets per second. In the case of a plurality of rows of nozzles, some rows may be of the multi-level deflection type while other rows may be of the binary level type. Preferably, the nozzles are arranged over substantially a full width of the treatment path and the coating is applied substantially over a full width of the textile. This width may be in excess of 1 meter, however it is common to produce textiles having widths of up to 2.5 meters. In a preferred embodiment, the coating is a water-repellent coating and the coating substance may comprises a fluorocarbon or silicon based emulsion, an anti-foaming medium, an electrolyte and a thickener. By applying such a coating in an open structure with pores between adjacent pixels, a breathable structure may be achieved. Preferably, the coating substance has a viscosity of greater than 4 centipoise as measured with a Brookfield viscosimeter. It has been found that use of a such viscosities with nozzle diameters of 70 microns or more ensures that droplets are formed having adequate form stability on impact with the textile, whereby the desired form of pixel is achieved. Lower viscosities may lead to greater wicking of the coating substance along and around the fibre structure. According to an important feature of the present invention, the treatment path may comprise a conveyor and the textile may be affixed to the conveyor, whereby the position of the textile relative to the conveyor may be maintained. In this way, when the precise location of each pixel is important, shifting of the textile may be prevented. This is particularly important when the treatment includes printing using different colours applied by different rows of nozzles. The textile may be affixed to the conveyor by means of adhesive or the like. The present invention also relates to a device for digitally coating a textile, the device comprising a conveyor for substantially continuously feeding the textile along a treatment path, a row of static coating nozzles arranged generally transversely across the path, for applying a coating substance over substantially the complete width of the textile, wherein the coating nozzles have outlet diameters of greater than 70 microns and are individually controlled to provide a substantially continuous stream of droplets that can be selectively directed to impinge on the textile. In the present context, static is intended to denote that the nozzles do physically move across the treatment path from one side to the other. Furthermore, the term continuous is intended to denote that the stream of droplets is continuous during operation of the device whereby those droplets that are not required are diverted to a collection device. Such a definition is considered to be clearly distinguish over so-called drop-on-demand systems. According to an advantageous embodiment, the device may additionally comprise a second or further rows of nozzles arranged generally transversely across the path, for applying a further substance to the textile. For performing a different finishing step such as dying or printing, the second row of nozzles may have outlet diameters of less than 70 microns, preferably about 50 microns. They are preferably also individually controlled to provide a substantially continuous flow of droplets that can be selectively directed to impinge on the textile. According to a particular embodiment of the device, rows of nozzles may be arranged on both sides of the path for coating or otherwise applying substances to both surfaces of the textile. In order to adequately and accurately perform the operation across the full width of the textile, each row of nozzles is provide on a printing beam spanning the treatment path. Preferably, each beam comprises a plurality of heads, each head comprising a number of nozzles. By using separate heads, the pressure distribution between individual nozzles may be carefully controlled. In particular, using around eight nozzles per head, adequate pressure control to each nozzle is ensured. In such case, a total of between 10 and 100 heads may be provided on each beam. According to a preferred embodiment, the nozzles are of the multi-level deflection ink-jet type, whereby the position of a droplet on the textile may be controlled. Alternatively, some or all of the rows of nozzles may be of the binary deflection ink-jet type, whereby a droplet exiting the nozzle can be selectively directed onto the textile or into a collector. Whichever type of nozzle is used, it is desirable that they can be controlled to each generate at least 100,000 droplets per second in order to achieve the required process speed. Preferably, the conveyor is wide enough to accommodate textiles of more than 1 meter in width, more preferably up to about 2 meters in width. It should also be arranged to operate at a speed of more than 15 meters per minute, more preferably at more than 25 meters per minute. It may also be provided with adhesive or the like for preventing relative movement of the textile. The present invention further relates to a digitally coated fibrous textile having mesh openings between adjacent fibres, the fibres having an average spacing of greater than 40 microns, the textile being provided with a coating comprising a plurality of pixels of coating material lying substantially on the surface of the textile, each pixel covering at least four mesh openings and having a diameter of more than 100 microns. Preferably, the textile is a woven or knitted textile. According to further particular embodiments of the invention, the textile may have a width of greater than 1.5 meters. Furthermore, the coating may be provided in the form of a closed coating with overlapping pixels or in the form of an open coating with pores between adjacent pixels. The invention will now be described in further detail with reference to a number of exemplary embodiments according to the annexed figures, in which: Figure 1 shows a schematic block diagram of the process of upgrading a substrate ; Figure 2 shows a view in perspective of a textile upgrader including a coating device according to the present invention; Figure 3 is a schematic side view of the textile upgrader of figure 2; Figure 4 is a schematic front view of the textile upgrader of figure 2; Figure 5 is a cut-away schematic view of the textile upgrader of figure 2; Figure 6 is a schematic representation of a preferred sequence for performing the different treatment steps; Figure 7 is a schematic representation of an alternative preferred sequence for performing the upgrading steps; Figure 8 is a schematic representation of a further preferred sequence for performing the upgrading steps; Figure 9 shows a schematic view of a portion of woven textile coated according to the invention; Figure 10 is a cross section through the textile of Figure 9 along the line 10-10; and Figure 11 shows a similar view to Figure 10 through a coated textile in which smaller droplets have been used. Figures 2-5 show a textile upgrader 1 according to a preferred embodiment of the invention. Textile upgrader 1 is built up of an endless conveyor belt 2 driven using electric motors (not shown). On conveyor belt 2 can be arranged a textile article T which can be transported in the direction of arrow Pl along a housing 3 in which the textile undergoes a number of operations. The textile is physically affixed to the conveyor by . means of an adhesive to prevent shifting of the textile during the process. Finally, the textile is discharged in the direction of arrow P2 by release of the adhesive. A large number of nozzles 12 are arranged in housing 3. The nozzles are arranged on successively placed parallel beams 14. A first row 4, a second row 5, a third row 6 and so on are thus formed. The number of rows may vary (indicated in figure 5 with a dotted line) and depends on e. g. the desired number and nature of the operations. The number of nozzles per row is also variable and depends among other things on the desired resolution of the designs to be applied to the textile. In the illustrated embodiment, the effective width of the beams is about 1 m, and the beams are provided with about 29 fixedly disposed spray heads, each having about eight nozzles per head. Each of the nozzles 12 generates a stream of droplets of substance. In the preferred continuous inkjet method, pumps carry a constant flow of ink or other medium through one or more very small holes of the nozzles. In the following, although reference will be made to ink and inkjet, this is understood not to be limiting and that other substances may also be ejected from the nozzles. One or more jets of ink, inkjets, are ejected through these holes. Under the influence of an excitation mechanism such an inkjet breaks up into a constant flow of droplets of the same size. The most used excitator is a piezo-crystal although other forms of excitation or cavitation may be used. From the constant flow of droplets of the same size which are now generated must be selected those droplets which are to be applied to the substrate of the textile and those which should not be applied. For this purpose the droplets are electrically charged or discharged. There are two variations for arranging droplets on the textile. According to the one method an applied electric field deflects the charged droplets, wherein the charged droplets come to lie on the substrate. This method is also referred to as binary deflection. According to another preferred method, also known as the multi-level method, the electrically charged droplets are usually directed to the textile and the uncharged droplets are deflected. The droplets are herein subjected to an electric field which is varied between a plurality of levels such that the final position at which the different droplets come to lie on the substrate can hereby be adjusted. In figure 5 is indicated with dotted lines that the different nozzles 12 are connected electrically or wirelessly) by means of a network 15 to a central control unit 16, which comprises for instance a microcontroller or a computer. The drive of the conveyor belt 2 is also connected to the control unit via network 15'. The control unit can now actuate the drive and the individual nozzles as required. Also arranged per row of nozzles 4-11 is a double reservoir in which the substance to be applied is stored. The first row of nozzles 4 is provided with reservoirs 14a, 14b, the second row 5 is provided with reservoirs 15a, 1 5b, the third row 6 is provided with reservoirs 16a, 16b and so on. The appropriate substance is arranged in at least one of the two reservoirs of a row. The different reservoirs are filled with appropriate substances and the nozzles 12 disposed in different rows are directed such that the textile article undergoes the correct treatment. In the situation shown in figure 6, reservoir 14a of the first row 4 contains cyan-coloured ink, reservoir 15a of the second row 5 contains magenta-coloured ink, reservoir 16a of the third row 6 contains yellow-coloured ink and reservoir 17a of the fourth row 7 contains black coloured ink. The textile article is provided in rows 4-7 with patterns in a painting/printing treatment. The nozzles in these rows have outlet diameters of about 50 microns. The reservoirs of the three subsequent rows 8-10 contain one or more substances with which the treated textile can be coated in three passages for the purpose of coating the textile, the nozzles in rows 8-10 have outlet diameters of 70 microns. The eighth reservoir 11 contains a substance with which the printed and coated textile can be finished. In this embodiment the textile article T is preferably treated at the position of the fifth to the eighth row with infrared radiation coming from light sources 13 in order to influence the coating of the finishing. Figure 7 shows another situation in which the textile undergoes another treatment sequence. The textile article T is first of all painted by guiding the textile along the first row 4 and second row 5 of nozzles. These rows 4,5 have nozzles of 70 microns and apply a relatively smooth coloured coating onto the textile. In the third to fifth rows 6-8 the painted textile is then coated as above, whereafter the finishing step is carried out in the sixth and seventh rows 9,10. In the embodiment shown in figure 8, the textile article is first of all guided along the first row 4 of nozzles. The nozzles in row 4 are of about 70 microns and provide a smooth full background colour to the textile over the full width. The textile article is subsequently guided along the second row 5 and third row 6 by means of the conveyor belt, wherein patterns are printed onto the prepared surface. Good definition can be achieved in the printing steps at rows 5 and 6 using fine nozzles of between 30 and 50 microns. The textile is then guided along the fourth to sixth rows 7-9 to coat the painted and printed textile in three passages, whereafter a final finishing treatment step is performed in the seventh and eighth rows 10,11. It is possible to treat different successively transported textile articles in different ways, in some cases even without the transport of the textile therein having to be interrupted. It is for instance possible by means of computer control of nozzles 12 to provide successively supplied textile articles with designs which differ in each case. It is also possible to have different substances applied to the textile through an appropriate choice of the reservoirs. The first reservoirs 14a, 15a, 16a are for instance used in each case for a first type of textile, while the second reservoirs 14b, 15b, 16b are used for another type of textile. In order to determine the environmental advantages of the present invention, use can be made of an example of a representative upgrading process in which a substrate passes through four cycles of unit operations for the purpose of painting, followed by four cycles for the coating and finally two cycles for the finishing. The quantification is based on the production of a 1,800 metre long and about 1.6 metre wide substrate of bleached and dried cotton with a weight of 100 grams per square metre of substrate. The painting, coating and finishing are herein each performed in one process run, with the necessary post-treatments and/or pre-treatments between these process runs. If the treatments can be carried out in one process run, the environmental advantages will therefore be even greater. In the traditional upgrading process, practically every component (painting, coating and finishing) takes place in and/or with a highly aqueous solution. In the digital process according to the invention a highly concentrated solution is sprayed directly onto the substrate with a precisely controlled dosage. Less water is hereby used. For the purpose of rinsing/washing out excess chemicals and auxiliary chemicals, practically every cycle of unit operations comprises a rinsing step. The number of rinsing steps can be reduced from ten in the existing process (four times painting, four times coating and twice finishing) to three in the present digital process (i. e. once painting, once coating and once finishing). Seven fewer rinsing steps are therefore needed. This means that a considerable reduction in the water consumption can already be realized by curtailing the rinsing. The total reduction in the water consumption is in many cases more than 90%. The energy consumption can also be reduced considerably, since among other things forced drying is not necessary, or is only necessary to a very limited extent, rinsing with hot/warm rinsing water is not necessary, or only to a very limited extent, and the mechanical handling of the substrate is very greatly reduced. In the known upgrading process drying usually takes place between the different unit operations, and also within operations when a cycle has to be carried out a number of times. The substrate can contain up to several times its own weight of water. Drying generally takes place in two phases. In the first phase the greater part of the water is removed from the substrate mechanically. In the second phase there follows thermal drying, wherein the remaining water present in the substrate is evaporated. Because the present digital upgrading process is performed almost without water, no water, or practically no water, has to be evaporated, such as for instance by drying, between the different upgrading steps and after the final upgrading step. A very considerable energy-saving is hereby realized. The limited drying which is necessary in some cases can be realized in most cases by means of directional W driers. In general as little as 70 % water by weight may be required for the coating substance. In digital processes, because of the very limited washing of the substrate required it will also be possible to considerably reduce the number of mechanical operations, including transport of the substrate between the different upgrading operations, compared to the known upgrading process. The electrical energy consumption will hereby also decrease considerably. In total, a reduction in the energy consumption by more than 90% may be realized. With current production techniques about 150 grams of wet substances (chemicals) are applied per square metre. In digital printing, owing to more precise dispensing, lower pressure and less absorption in the textile, the quantity of chemical substances to be applied can be reduced to about 50 grams of wet substance per square metre. It is hereby possible to make a saving of about 66% in the chemicals. The saving relates not only to the primary chemicals but also to the additives, such as salts, with which the substrate is pre-treated in the digital process in order to facilitate the action, fixation and/or reactivity of the primary chemicals. It is expected that a saving of 66% can also be made on these additives. Finally, the waste water production and the contamination impact of the waste water can be reduced by more than 90%. Figure 9 shows a schematic view of a portion of woven textile 100 on which four pixels 102 of a coating material have been deposited. The textile 100 comprises fibres 104 arranged in a mesh with mesh openings 106 between the fibres 104. The fibre spacing is approximately 40 microns and the pixels 102 each have a diameter of approximately 100 microns. As can be seen from Figure 9, each pixel 102 effectively covers at least four complete openings 106. Additionally, it can be seen that the pixels 102 do not form a completely closed coating in that a pore 108 is formed between adjacent pixels 102. Figure 10 is a cross section through the textile 100 of Figure 9 along the line 10-10. It can be seen that the pixels 102 are generally located on the surface of the textile, spanning the openings 106 between adjacent fibres 104. Because of the viscose nature of the coating substance, each pixel 102 partially maintains its shape and although the pixels 102 flow together in the overlap region, the individual pixels are still discernable. It can furthermore be seen that the coating substance forming the pixel 102 partially envelopes the fibres 104 on the coated surface to form a good bond therewith. The viscosity of the coating substance is chosen to ensure the correct degree of impregnation of the material. Figure 11 shows a similar view to Figure 10 taken through a textile 100 in which smaller droplets 110 of a coating substance have been applied. The droplets 110 are of a similar size to the mesh opening 106 and tend to pass into and even through the openings. The resultant effect is less homogenous than in the case of Figure 10 and it is also more difficult to provide a different characteristic to the opposite facing surfaces of the textile. While Figures 9 and 10 illustrate the case of a textile weave of approximately 40 microns, it is also within the scope of the invention that even coarser weaves or structures may be used. Thus, for fibre spacing of 100 microns, a nozzle size of 200 microns could be contemplated. The invention is not limited to the above described preferred embodiments. In particular, the rights sought are rather defined by the following claims, within the scope of which many modifications can be envisaged.

CLAIMS 1. A method of digitally forming a coating on a fibrous textile having mesh openings between adjacent fibres, the method comprising: continuously feeding the textile along a treatment path having a row of static coating nozzles arranged generally transversely across the path, the coating nozzles having outlet diameters of greater than about 70 microns; supplying the nozzles with a supply of a coating substance; individually controlling the nozzles to provide a substantially continuous stream of droplets of the coating substance; selectively directing the individual droplets to impinge on the textile to form a coating of pixels lying generally on one surface of the textile, each pixel covering at least four mesh openings and having a diameter of more than 100 microns. 2. The method according to claim 1, further comprising feeding the textile along a second row of static nozzles also arranged generally transversely across the path, supplying the second row of nozzles with a supply of a second substance and individually controlling the nozzles to provide a substantially continuous stream of droplets of the second substance to the textile. 3. The method according to claim 2 wherein the second row of nozzles comprises nozzles having outlet diameters not greater than about 50 microns. 4. The method according to claim 2 or claim 3, wherein the second substance is applied prior to the coating substance and is received within the fibrous structure. 5. The method according to claim 2 or claim 3, wherein the second substance is applied after the coating substance and forms individual pixels on the coating. 6. The method according to any preceding claim, wherein the nozzles are of the continuous inkjet multi-level deflection type and the method comprises electrically charging or discharging the droplets, applying an electric field, and varying the electric field so as to deflect droplets such that they are individual deposited at suitable positions on the textile. 7. The method according to any preceding claim, wherein each nozzle generates at least 100,000 droplets per second. 8. The method according to any preceding claim, wherein the nozzles are arranged over substantially a full width of the treatment path and the coating is applied substantially over a full width of the textile. 9. The method according to any preceding claim, wherein nozzles are provided on both sides of the treatment path and the method further comprises applying the coating on both surfaces of the textile. 10. The method according to any preceding claim, wherein the coating is applied with an open structure comprising spaces between adjacent pixels. 11. The method according to any preceding claim, wherein the coating is a water- repellent coating. 12. The method according to any preceding claim, wherein the coating substance comprises a fluorocarbon or silicon based emulsion, an anti-foaming medium, an electrolyte and a thickener. 13. The method according to any preceding claim, wherein the coating substance has a viscosity of greater than 4 centipoise as measured with a Brookfield viscosimeter. 14. The method according to any preceding claim, wherein the treatment path comprises a conveyor and the textile is affixed to the conveyor to substantially prevent relative movement therebetween. 15. A device for digitally coating a textile, the device comprising : a conveyor for substantially continuously feeding the textile along a treatment path; a row of static coating nozzles arranged generally transversely across the path, for applying a coating substance over substantially the complete width of the textile, wherein the coating nozzles have outlet diameters of greater than 70 microns and are individually controlled to provide a substantially continuous stream of droplets that can be selectively directed to impinge on the textile. 16. The device according to claim 15, further comprising a second row of nozzles arranged generally transversely across the path, for applying a further substance to the textile. 17. The device according to claim 16, wherein the second row of nozzles have outlet diameters of less than 70 microns and are also individually controlled to provide a substantially continuous flow of droplets that can be selectively directed to impinge on the textile. 18. The device according to any of claims 15 to 17 in which rows of nozzles are arranged on both sides of the path for applying substances to both surfaces of the textile. 19. The device according to any of claims 15 to 18, wherein each row of nozzles is provided on a printing beam comprising a plurality of coating heads, each coating head comprising a plurality of nozzles. 20. The device according to any of claims 15 to 19, wherein the nozzles are of the multi-level deflection ink-jet type, whereby the position of a droplet on the textile may be controlled. 21. The device according to any of claims 15 to 19, wherein the nozzles are of the binary deflection ink-jet type, whereby a droplet exiting the nozzle may be selectively directed onto the textile or into a collector. 22. The device according to any of claims 15 to 21, wherein the nozzles are controlled to each generate at least 100,000 droplets per second. 23. The device according to any of claims 15 to 22, wherein the conveyor is arranged to operate at a speed of more than 15 meters per minute. 24. A digitally coated fibrous textile having mesh openings between adjacent fibres, the fibres having an average spacing of greater than 40 microns, the textile being provided with a coating comprising a plurality of pixels of coating material lying substantially on at least one surface of the textile, each pixel covering at least four mesh openings and having a diameter of more than 100 microns. 25. The digitally coated fibrous textile according to claim 24, wherein the textile is woven or knitted. 26. The digitally coated fibrous textile according to claim 24 or claim 25, wherein the textile has a width greater than 1.5 meters.
IPRP1 27.03.2006 International Preliminary Report on Patentability Chapter I 7 pages
WOSA 22.03.2006 Written Opinion of the International Search Authority 6 pages
Publication 12.05.2005 Later publication of international search report (A3 19/2005) 4 pages
DECLA 31.03.2005 Declaration 1 page
Pr. Doc. 31.03.2005 NL PCT/NL03/00841 28.11.2003 26 pages
Pr. Doc. 31.03.2005 NL 1024338 22.09.2003 26 pages
Publication 31.03.2005 Initial Publication without ISR (A2 13/2005) 25 pages

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