EP0695384B1 - Process for coating yarns and fibres in textile objects - Google Patents

Abstract

Textile bodies may be coated by physical or chemical vapour deposition in the gaseous phase. The layers deposited on the fibres or filaments have a high quality. It is thus possible to coat filaments or fibres without leaving any pores even with very thin layers, which cause however an imperceptible increase of the total volume of the textile object. Because of the high mobility of the coating material particles, even critical spots, such as the chaining spots in meshed or woven goods, are reliably coated. The same is valid also for complex designed, three-dimensional textile shaped bodies. Besides coatings by simple deposition, surface polymerisations may also be carried out, forming impenetrable layers on the textile material, which either protects it against the environment (allergy, sensitivity to air or light) or confer new properties to it (electric conductivity, antiadhesive coating). Coating in the gaseous phase also prevents in many cases the textile body to be processed from drying out.

Description

The present invention relates to the coating the surfaces of textile structures, especially threads, and fibrils in textile articles.

The common technique of surface treatment in The area of textile production is that the filaments or threads are coated before further processing or by a chemical or physical Processes are modified superficially. In limited These procedures are also applicable to intermediate or textile scope End products applicable. Chemical treatment and the usual methods of applying the coating the coating material or the chemical reagent by spreading, spraying, etc. onto the textile material or immersing the textile material in a liquid Treatment medium.

Problems have always arisen with these known methods then when there is a treatment of the threads before processing ban, e.g. B. when the treated threads are no longer could easily be spun or entangled and hence a textile object, be it a semi-finished product or an end product that needed to be treated. In particular, could it cannot be ensured that with the treatment methods mentioned also the individual threads without gaps and were reliably coated or treated. problem areas provided e.g. the crossing points of the threads in woven or knitted fabric. Similar problems posed with increased demands on the treatment of the filaments in multifilament yarns or twists.

With the increasing importance of ecological aspects the disadvantage of the known methods also came to the fore, that used treatment media because of that in it contained solvents or components other than Special waste had to be disposed of.

EP 496 117 A describes a method for producing a an equipment provided, especially synthetic fiber Sewing thread described. Here is right after spinning the sewing thread applied equipment. This is the equipment themselves or become monomers or oligomers on the yarn applied the radically / ionically oligomerizable / polymerizable are and form the equipment. The radicals and / or ion-producing treatment can be carried out by Low temperature plasma treatment can be formed. This method however, is very time consuming and affects the properties of the yarn in the subsequent production of the textile Structure.

EP 492 649 A 3 describes a method for changing the Properties of a textile substrate, being on the substrate an initiator is applied by physical treatment breaks down into radical and / or ions. Simultaneously or subsequently one carries out the physical treatment and brings the resulting radicals with the textile substrate or a substance applied thereon for reaction. This method has the disadvantage of being a chemical initiator is required, on the one hand, a greater outlay on chemical Aids required and secondly from the point of view environmental compatibility is not harmless. Because chemical initiators are usually relatively aggressive Substances whose disposal is only possible with considerable effort is.

It is therefore an object of the present invention to provide a method for the treatment of the surface of threads or textile structures indicate that a qualitatively improved surface treatment of the components by means of which the liability of the Treatment agent is increased on the surface and that is relatively environmentally friendly.

Such a method is specified in claim 1. preferred Designs and applications as well as products are Subject of the further claims. Under a textile structure is to understand everything that is made of textile material, especially from filaments or fibers or ribbons, by one of the processes common in the textile industry, especially weaving, knitting and knitting is produced, So everything from the thread to the textile end product as well for example nonwovens. Not considered a textile structure however, the fibers or filaments themselves. Threads or yarns are generally linear textile structures, in particular all made from fibers or filaments. Textiles Material is the material from which the textile structure is made can consist of fibers or filaments Natural or synthetic fiber also metal threads, stone fibers, Glass fibers etc.

The invention is based on the surprising finding that the coating processes known from the gas phase for coating solid objects made of plastic or metal can be applied to threads or filaments and fibers in a textile structure, and lead to products with properties which have not hitherto or were only available with disproportionately high expenditure. The treatment medium is generated in the process by chemical (CVD) (Römpp Chemie Lexikon, 9th edition (1990), volume 2) or physical (PVD) methods (Römpp Chemie Lexikon, 9th edition (1992), volume 5). Preliminary tests for modifying the chemical or physical properties of textile materials using a PVD process, the low-temperature plasma process, are known (Y. Rogister, J. Knott, L. Ruys, M. Van Lancker, Etude de l'Influence de Nouvelles Techniques de Traitement de Surface sur les Propriétés des Fibers, Techtextil Symposium 1992). In these experiments, a plant for the treatment of plastic films was used, which generated the plasma by electromagnetic excitation. A vacuum of up to 1.33 Pa (10 ^-2 Torr) was generated in this system during the treatment and the influence of the plasma on the textile was investigated, changes in the wettability, the surface structure and also the mechanical properties being observed and essentially abrasive effects were in the foreground. Surprisingly, it has now been found that such techniques can also be used to apply layers to textile material.

The high mobility of the reactive gas particles generated leads to the fact that every single thread in textile structures or each fiber reliably in its entirety superficial is applied and that in the treatment of The individual fibers are also twisted or multifilament be coated. With the method according to the invention produced coatings adhere much stronger than conventional layers and can be used as a non-porous coating of the textile material. It will possible to use threads made of materials whose mechanical Properties are desirable, however to react superficially with the environment. Examples are moisture sensitive or called allergy-causing materials.

The spectrum according to the invention is also the spectrum possible surface coatings greatly expanded.

It can e.g. B. metal layers are applied to a to maintain electrical conductivity or optical To influence impression. It can be right on the surface each fibril of the substrate was polymerized when treating with a gaseous Monomer is carried out. It is also possible to be in preparation the coating first with the same procedures intensive cleaning or preparation of the surfaces perform such. B. the dry removal of a Avivage, which is already compared to the known methods significantly better adhesion or treatment intensity can be increased again. It can vary depending on the process conditions continuous or discontinuous Layers are created.

With regard to the environmental problem, it should also be emphasized that the method according to the invention is not a solvent or other liquid carriers and no drying processes must be done, reducing energy consumption is significantly reduced. Because of the high quality converting it is also possible the total amount of the coating or reaction material, because the treatment from the gas phase is extremely uniform Effect on the surfaces to be treated guaranteed.

Even the treatment of sensitive materials with highly reactive Substances for chemical modification of the surface, which are usually high temperatures in the known processes presuppose or were not possible at all, can be carried out according to the inventive method, because the thermal load on the object to be treated reduced by setting suitable process parameters or can be avoided. In particular, the ions of Plasma in a low pressure plasma treatment at room temperature.

The present method is also very suitable for Impregnation of voluminous or three-dimensionally shaped Textile bodies such as B. spacer fabric, spacer fabric or non-woven fabrics. The impregnation or the layer structure also takes place in volume and coated inside construction all fibers.

A preferred embodiment of the method according to the invention consists of converting a textile body into a conventional one Chamber for PVD coating using the low-temperature plasma process bring to. To be even To get access to the treatment gas will the textile body by a support frame or a Tensioning frame held so that the surfaces as possible are freely accessible. The process parameters according to the planned coating are set, i.e. vacuum, Gas entry and temperature. For a superficial polymerization of a gaseous monomer becomes a permanent one Inflow of monomer gas set. To be evaporated Treatment agents are as usual in this procedure Solid or as a powder or granules in which Treatment chamber introduced. As a gas in the treatment atmosphere come noble gases, for example argon, but also Nitrogen and oxygen in question. The selection judges according to the properties of the respective coating Substrate and the coating material.

When applying a DC glow discharge hit plasma particles u. a. on the treatment agent in the solid form and lead to its evaporation. gaseous Treatment agents such as B. monomer gas, can either directly through the action of the excitation energy or activated indirectly by the plasma of the carrier gases, z. B. by formation of radicals.

An ionic interaction between the separating ones Particles and the surface, d. H. the substrate, leads to particularly firm and very stable layers. A particularly strong connection between layer and Substrate occurs when chemical Bonds formed between the substrate and the layer be, e.g. B. by grafting. Very stable layers will be obtained when crosslinking the polymerization, in particular three-dimensional networked structures. Often a cleaning process was observed before deposition, which is also enforced by appropriate process parameters or can be promoted, creating a deep cleaning the surfaces of the textile body to be treated and thus a high quality of the coating is achieved.

Advantageous of a coating due to superficial Polymerization according to the present invention is that the activated monomer particles despite their excitation, e.g. B. Ionization, have only a little elevated temperature and thus polymerization even on temperature-sensitive Materials such as thermoplastics can be made. It is also possible to be non-polymerizable in the usual chemical way Use substances such. B. alkanes, since under under the effect of a glow discharge such molecules Breakage of bonds or cleavage of fragments in ignore reactive forms.

With the method according to the invention, for example textile body made of polyethylene threads coated with PTFE, which makes the high tensile strength of the polyethylene with the The non-stick effect of the PTFE could be combined. carbon fibers can be counteracted by an appropriate coating protect the oxygen in the air. The secluded Layers can be cleaned, washed and even boiled and (steam) sterilization resistant.

It is also possible to treat webs of textile material. The textile material can be rolled into the treatment chamber introduced and in this during the treatment period be rolled over, or the textile material can be drawn through the chamber from air to air, for which the chamber have entrance and exit locks got to.

In summary, therefore, according to the method according to the invention on holistic textile body with new surface-related Properties. The surface treatment takes place intensively and because of the treatment the gas phase very evenly even in the already woven or meshed material, and the layers applied can be kept very thin because of the high quality, z. B. thinner than 1% of the fiber diameter or only a few hundred atomic or molecular layers thick, so that one noticeable increase in volume due to the coating avoided can be. Among other things, the following surface properties can be used by choosing the appropriate treatment agent (s) set: antibacterial equipment, wash and boil resistant; fungicidal properties; wettability; UV-IR absorption; Radiation, especially IR, UV, light reflection; lubricity; Wrinkle properties; flammability; Anti Pilling; electric conductivity; etc. The layers adhere very well to the surfaces of the textile material and are even in the finest gaps well trained. This is also advantageous for a penetrating one Treatment of voluminous textile structures possible, such as Spacer fabrics, knitted fabrics, fleeces and felt. With the invention Processes can also be encased with materials be carried out, their use according to the known Process came too expensive because the invention was only minor Quantities are necessary and thus the importance of the material cost factor is generally pushed back.

The provided by the invention Fiber sheathing is the existing process stage Systems and coating processes can be implemented.

The invention uses technology in the textile sector, previously only in other technical areas, e.g. in metal treatment for surface hardening and in PCBs for CFC-free reliable cleaning also in finest drill holes have been used. This Technology becomes accessible for flat and spatial textiles made. The molecules of the monomer are caused by collision with the high energy Particles, the electrons present in the gas discharge, stimulated and to a large extent also fragmented, i.e. smashed into pieces of molecules. This allows the monomers and fragments in the gas space react with each other on all surfaces. These reactions are the actual basis of plasma polymerization.

The plasma that stimulates these processes is an ionized gas, that of ions, electrons, light quanta, atoms and molecules consists. Due to the possibility of low temperature coating it is possible to coat in vacuum at room temperature. This means that even thermoplastics (e.g. polyethylene or polypropylene) be coated. The resulting layers are highly cross-linked in three dimensions and have excellent adhesion on the substrate.

With the same system, there are also abrasive processes possible. For example, by igniting an oxygen plasma a "cold combustion" can be generated. Here organic or greasy contaminants without environmentally harmful chemicals ablated. Only an ash-like residue remains left.

Both processes, the removal and application can be done by the corresponding Control of the parameters in one operation, i.e. at a reactor feed. This can ensure be that a coating matrix only on an absolutely clean Substrate is applied.

Another aspect of the application and ablation plasma technology is the 100% sterilizing effect of the plasma (destructive effect on organisms). Also through the packaging from e.g. All bacteria can be bandaged through reliably kill.

The coating process of plasma technology is a very economical and therefore also environmentally friendly technology. The electrical energy consumption is very low. These are all Advantages over the known wet processes, which are related the process steps are both time-consuming, energy-consuming and costly are because the liquor (water) is heated up and on Temperature must be maintained. Then again is a high energy consumption for drying necessary. These process steps fall away. Furthermore, the disposal of the Chemical residues usual in the wet process.

The layers that can be applied using plasma have completely new properties because of the high degree of networking fundamentally different from those of a conventional one from monomers manufactured polymer differ. The polymer is always a duromer, is very temperature-resistant and already in low Layer thickness free of pinholds (smallest uncovered areas) and is almost invulnerable to no solvent.

The energetic particles excited in the plasma therefore dissolve with the monomer (gas) intense and profound effects. The cold plasma represents high energies in chemically very effective Mold ready at room temperature. Similar reactions are e.g. not feasible in the hot flame. It can be practical all organic compounds are caused to form layers.

According to the invention, there is a special plasma within the textile surface each fibril covered by a thread. The discharge reached thus also very complicated shaped parts, undercuts and also covers the non-exposed contact areas of the fibers. The volume properties of the coated Textiles are not affected noticeably or visibly.

The textile is in a vacuum tank during the treatment. Any excess or waste gases that may arise are sucked off by a vacuum pump and can be easily collected or returned to the reaction as a cycle become. In principle, there is one in the plasma process uncontrolled distribution of questionable substances not too expect.

Because of the very thin layers, the material costs are very high low.

• Beeinflussung der Oberfläche durch Abtragung
• Beeinflussung der Oberfläche durch Beschichtung
• Einstellung der Benetzbarkeit (hydrophil)
• Steigerung/Verminderung der Haftbereitschaft (hierdurch problemlose Färbung)
• Erzeugung elektrisch isolierender/leitfähiger Schichten
• Einstellung der Permeationsdaten für Gase und Flüssigkeiten
• Steigerung der Abrasionsbeständigkeit
• Änderung des Reflexionsverhaltens (UV- und IR-Schutz)
• Änderung des Gleitverhaltens.

Finally, some effects that can be achieved with low-temperature plasma are listed:

• Influencing the surface by ablation
• Influencing the surface by coating
• Wettability adjustment (hydrophilic)
• Increase / decrease in the readiness for detention (thereby problem-free coloring)
• Generation of electrically insulating / conductive layers
• Setting the permeation data for gases and liquids
• Increased abrasion resistance
• Change in reflection behavior (UV and IR protection)
• Change in gliding behavior.

The reactor for coating the textile Substrate can either be designed as a bell reactor, where the monomer feed is from above. The substrate is located near the cathode or in the cathode drop area, because there the degree of ionization of the coating monomer is high. The flow form is a radial overflow of the Substrate.

A tubular reactor can also be used in which the Electrodes are arranged parallel to the tube axis. The substrate the monomer flows over here in parallel.

Plasma polymerization can be broken down into five steps, some of which run in parallel.

In the first step, initiation, monomers are in the gas phase activated or radicalized by electron impact. Moreover become monomers adsorbed on the substrate surface by electron, ion or photon bombardment to react with other monomers.

A second step, adsorption, describes adsorption of monomers and radical species on the substrate surface. Chain growth is described in a third step. Here, reactions between radicals can occur and monomers in the gas phase, adsorbed radicals and gaseous monomers, as well as adsorbed radicals and adsorbed Monomers.

The fourth step, termination, leads to the formation of polymer Structures. By reacting longer chain radicals in In the gas phase, polymers can be formed in the gas phase. By the reaction of radicals from the gas phase with adsorbed Radicals or adsorbed radicals with each other arise Polymers adsorbed on the substrate.

A fifth step, the reinitiation, describes on the one hand the repeated fragmentation of the polymer already formed in the gas phase by the action of the plasma and on the other the process of three-dimensional crosslinking of the polymer the surface of the substrate by the action of ions, electrons and photons.

The plasma polymerization is in a pressure range between 0.01 mbar and 10 mbar. At low pressures the achievable deposition rates are too low, while at higher ones No transparent continuous layers are expressed with the desired properties.

1) Adhäsive Funktionsschichten, die folgende Eigenschaften beeinflussen: Bedruckbarkeit, Lackierbarkeit, Metallisierbarkeit Klebbarkeit, Benetzbarkeit, Hydrophilisierung, Hydrophobisierung, Antiadhäsivierung, Schichtverbundfestigkeit, Teilchenverbundfestigkeit und Faserverbundfestigkeit.

2) Optische Funktionsschichten, die folgende Eigenschaften beeinflussen: Farbstabilität, Brechungsindex, Antireflexionswirkung, Antibeschlagwirkung, Entspiegelungswirkung, Adsorptionskoeffizient.

3) Textile Funktionsschichten, die folgende Eigenschaften beeinflussen: Festigkeit, Formbeständigkeit, Bedruckbarkeit, Färbbarkeit, Farbechtheit, Farbhaftung, Klebbarkeit, Flammfestigkeit, statische Aufladbarkeit, Schmutzempfindlichkeit, Wasseraufnahmevermögen, Antifilzwirkung.

4) Biomedizinische Funktionsschichten, die für Textilien im medizinischen Bereich eingesetzt werden können. Diese beeinflussen z.B. folgende Eigenschaften: Organofilierung, Biokompatibiltät, immunbiologisches Verhalten, Antitoxizität.

5) Elektrische Funktionsschichten, die die elektrischen Eigenschaften der Fasern beeinflussen: Dielektrizitätskonstante, Isolationswiderstand, antistatisches Verhalten, Leitfähigkeit.

6) Chemische Funktionsschichten zur Beeinflussung der folgenden Fasereigenschaften: Migrationsschutz, Diffusionsschutz, Korrosionsschutz, Lösungsmittelresistenz.

7) Mechanische Funktionsschichten zur Steuerung der folgenden Eigenschaften: Verschleißverhalten, Abrasionsschutz, Reibungskoeffizient.

8) Permeable Funktionsschichten zur Steuerung von z.B. Porosität und Permeabilität.

9) Thermische Funktionsschichten zur Beeinflussung der Formbeständigkeit, Haftfähigkeit und Wärmereflektion der textilen Fasern.

There are nine groups of functional layers applied to textiles by plasma technology:

1) Adhesive functional layers that influence the following properties: printability, paintability, metallizability, adhesiveness, wettability, hydrophilization, hydrophobization, anti-adhesion, layer strength, particle strength and fiber strength.

2) Optical functional layers that influence the following properties: color stability, refractive index, anti-reflective effect, anti-fog effect, anti-reflective effect, adsorption coefficient.

3) Textile functional layers that influence the following properties: strength, dimensional stability, printability, dyeability, color fastness, color adhesion, adhesiveness, flame resistance, static chargeability, sensitivity to dirt, water absorption, anti-felt effect.

4) Biomedical functional layers that can be used for textiles in the medical field. These influence, for example, the following properties: organofiltration, biocompatibility, immunobiological behavior, antitoxicity.

5) Electrical functional layers that influence the electrical properties of the fibers: dielectric constant, insulation resistance, antistatic behavior, conductivity.

6) Chemical functional layers to influence the following fiber properties: migration protection, diffusion protection, corrosion protection, solvent resistance.

7) Mechanical functional layers to control the following properties: wear behavior, abrasion protection, coefficient of friction.

8) Permeable functional layers for controlling, for example, porosity and permeability.

9) Thermal functional layers to influence the dimensional stability, adhesiveness and heat reflection of the textile fibers.

Every coating monomer has because of its chemical composition and structure as well as due to the required process parameters its own polymerization kinetics. The rate of polymerization and thus the rate of growth of layers of different monomers differ considerably. For example, the coating rates for monomers with high molecular weights usually higher, since larger low molecular weight ones Form and add fragmentation products. It can be used to achieve different desired properties several monomers at the same time or in succession by plasma technology be applied to the textile substrate.

Claims (13)

1. A method of treating the surface of threads, consisting of one or more filaments, and of threads in textile structures with a treatment agent comprising the step of activating said treatment agent in a plasma in which said treatment agent is translated into a gaseous or plasma state and deposited on the surface of said threads or filaments, said treatment agent being translated into a reactive form by the effect of glow discharge and in the course of the deposition chemical bonds being formed between said filament or thread and the coating of said treatment agent to be deposited.
2. The method as set forth in claim 1, characterized in that the treatment is implemented at a total gas pressure of maximally approx. 10 kPa.
3. The method as set forth in claim 1 or claim 2, characterized in that said treatment agent is made available by evaporating a solid body of a coating material.
4. The method as set forth in any of the claims 1 to 3, characterized in that said treatment agent in the gaseous state is translated into a chemically reactive state by an electric discharge or interaction with plasma particles of the environment generated by irradiation with energy, more particularly by electromagnetic fields.
5. The method as set forth in any of the claims 1 to 3, characterized in that said treatment agent is translated by the effect of radiation and/or heat into a state in which said treatment agent is capable of being deposited on the surface to be coated.
6. The method as set forth in claim 4 or 5, characterized in that said treatment agent is polymerizable and caused to polymerize indirectly, via energized or reactive particles in the atmosphere of the treatment space, or directly.
7. The method as set forth in any of claims 1 to 6, characterized in not the structure to be cooled or heated by micro waves.
8. The method as set forth in any of the claims 1 to 7 for coating textile material and structures consisting at least in part thereof, characterized in that said threads or filaments of said textile material are homogenously sheathed by a coating generated from said treatment agent by surface deposition or polymerization.
9. The method as set forth in any of the claims 1 to 7 for coating textile material, characterized in that the threads or filaments of said textile structure are homogenously provided with a surface comprising one or more of the following properties: electrically conductive, electrically insulating, metallic, gas-impermeable, radiation reflective, light-reflective, antibacterial, fungicidal, cleansing-compatible, sterilization-compatible.
10. The method as set forth in one of claims 1 to 7,
    characterized in that a plasma coating is effected at room temperature.
11. The method as set forth in claim 10,
    characterized in that the plasma coating is effected by PVD or CVD process.
12. The method as set forth in one of the preceding claims, characterized in that before the coating by the ignition of an oxygen plasma a cold burning is effected for removing organic impurities of the substrate.
13. The method of claim 12, characterized in that the ignition of the oxygen plasma and the subsequent coating are effected in one step.