WO2011086186A1

WO2011086186A1 - Plasma- or ion-based system for producing coatings on fluoropolymers, said coatings having good adhesion

Info

Publication number: WO2011086186A1
Application number: PCT/EP2011/050552
Authority: WO
Inventors: Markus Kahn; Juergen M. Lackner; Wolfgang Waldhauser; Paul Hartmann; Andreas Rudorfer; Stefan Koestler
Original assignee: Joanneum Research Forschungsgesellschaft Mbh
Priority date: 2010-01-18
Filing date: 2011-01-17
Publication date: 2011-07-21
Also published as: DE102010000983A1; EP2526218A1

Abstract

The invention relates to a method for depositing a coating on a fluoropolymer, which coating has a good adhesion. According to said method, a substrate comprising a fluoropolymer is coated with a carbon-containing layer by means of a plasma, and the plasma is composed of plasma particles having a mean energy ranging between 50 eV and 3000 eV.

Description

Plasma- or ion-based system for the production of adhesive coatings on fluoropolymers

The invention relates to a method for adherent deposition of a coating on fluoropolymers.

Moreover, the invention relates to a layer arrangement. Furthermore, the invention relates to a device or coating system for adherent deposition of a coating on fluoropolymers.

Fluoropolymers are plastics with strong carbon-fluorine bonds. In addition to PTFE (polytetrafluoroethylene, polytetrafluoroethene, Teflon®) belong to this group of polymers PFA (perfluoroalkoxylalkane), FEP (fluorinated ethylene-propylene), PVF (polyvinyl fluoride), PVDF

(Polyvinylidene fluoride), PCTFE (polychlorotrifluoroethylene), etc. From this group, PTFE is a fully fluorinated polymer and very inert.

Even aggressive acids such as aqua regia can not attack PTFE. The reason lies in the particularly strong bond between the

Carbon and fluorine atoms, since fluorine is the element with the strongest electronegativity. Thus, many substances (bases, alcohols, ketones, gasolines, oils) fail to break the bonds and react chemically with PTFE.

This leads to problems in the area of activation of general

Fluoropolymers and especially, as technically applied in the largest amount, of PTFE surfaces in preparation for bonding or

Coatings. Chemically, it can only be prepared by the possibility of formation of alkali fluorides from organically bonded fluorine atoms for a strong metallization. For this purpose, sodium is used industrially in liquid ammonia or naphthyl sodium in tetrahydrofuran. However, these chemical bonds have only one Very low proportion of the adhesion of metal layers to PTFE, which is much greater contribution in chemical etching by the

achieved mechanical anchoring due to cavitation. While chemical etching of PTFE occurs in environmentally benign baths, much more environmentally friendly processes are mechanical roughening for cavitation (e.g., sandblasting), laser radiation for surface conversion (US 5,635,243, US 5,643,641), superficial copolymerization of polymer layers (S.Wu et al. / Polymer 40 (1999) 6955-6964) or the use of

Plasmas. In the latter technique, the surface is attacked by ions and atoms with kinetic energy. The application of plasmas is carried out using process gases many times in coarse, fine or high vacuum (that is, process pressures <10 mbar), various

Technologies also work under atmospheric pressure.

It is known from the literature (eg Rother et al., Plasma coating process and hard coatings, Leipzig, Dt. Verl. Für Grundstoffindustrie, 1992) that the plasma effect (i.e., the

In the range of thermal particle energies (about 0, 1 eV), adsorption and condensation processes dominate more freely (gas particles on the surface of the solid, which for one

Surface activation does not bring any beneficial effects. Kinetic particle energies in the range of 1 eV to 10 eV correspond to the binding energies of single atoms in the solid state. The particles crowd into already existing atomic ones

Surface structures of the solid (incorporation), whereby only a few atoms can be changed in their position. With a Increasing to 10 eV and 1000 eV, the particles hitting the solid mass give their energy to an entire ensemble of atoms. As a result, the nuclear order is significantly changed. The dusting ("sputtering", detachment of individual atoms from the volume or from the surface of the solid to be treated) already firmly bound atoms of the solid surface is at

Particle energies of some 100 eV to 1000 eV found. As the particle energy continues to increase, the particles become solid

implanted. In a multitude of stochastic processes, the particles release their energy to individual solid atoms and are decelerated. However, until complete standstill, the particles have traversed distances of up to several tens of nanometers in the solid state (depending on the ion species, the material of the solid, etc.). The incorporation of the decelerated atoms leads to

Deformations of the original atomic structure or lattice of the

Solid. In addition, radicals in reactive plasmas can react with the solid surface and thus chemically chemically surface

change. Oxygen radicals purify the surface of organic contamination by oxidation, but can also introduce polar functional groups such as C = O, OH and CO ₂ H into the plastic surface (R. H. Hansen, JV Pacale, T. De Benedictis, P. M. Rentzepis, "Effect of Atomic Oxygen on Polymers," J. Polym., See, A3 (1965) 2205.).

For fluoropolymers, the use of plasmas has been demonstrated almost exclusively for PTFE: low-energy plasmas (so-called plasma treatment), for example S0 ₂ plasma treatment, partly with H ₂ plasma pretreatment (J.C. Caro et al. / European Polymer Journal 35 (FIG. 1999) 1149-1152; JC Caro et al., Surface and Coatings Technology 116-119 (1999) 792-795) reduce the high surface energy of PTFE prior to the application of electrochemical coating techniques clearly, which increases the layer adhesion. Another is also the

Pre-treatment of PTFE by means of microwave-excited argon plasma possible (Andreas Weber, Thorsten Matthee, final report:

Collaborative project: Environmentally friendly methods for adherence

Metallization of plastics and their use in

electronic / mechanical functional elements; VDI Dusseldorf; 1998). CF ₄ plasma prior to palladium electrochemical seeding results in similar adhesion results to the chemical activation methods described above.

The more intense effect of higher-energy plasmas (so-called.

Ion treatments) showed several authors for PTFE by means of increased surface energy: DE 2457694 discloses ion treatment of PTFE with oxygen and halogen compounds. WO 92/18320 discloses ion-treated, medical PTFE catheters. Kerezturi et al. (K.

Kereszturi et al. / Surface & Coatings Technology 202 (2008) 6034-6037) discloses the displacement of fluorine by carbon on the PTFE surface after treatment with a 1 keV saddle field fast atom source with hydrogen, helium and nitrogen. Nitrogen ion treatments with up to 20 keV energy were also reported by Zhang et al. (Zhang J. Z. et al., Surface & Coatings Technology 187 (2004) 250-256), where the otherwise very time-dependent, rapidly recovering activation effects for several months could be detected. When using conventional plasma treatments in a vacuum to activate plastic surfaces, a coating, usually a metal (Cu, Al, Ti, etc.) or a metal compound (metal nitrides, metal oxides, etc.) can subsequently be deposited on the activated surface by means of a vacuum coating method become . The

Vacuum coating methods are generally in Physical Vapor Deposition (Physical Vapor Deposition, PVD) and Chemical Vapor Deposition (CVD) are different. While in PVD processes the coating source is a solid (target) from which atoms are removed (vaporized), in CVD processes the process gas is the source of the atoms to be deposited. In the field of coating plastics, a variety of vacuum deposition techniques are used (thermal vapor deposition, magnetron sputtering, pulsed laser deposition, arc evaporation, plasma activated CVD (PACVD, PECVD), plasma polymerization, etc.). In addition to the process variant of

In many cases plasma pretreatment in vacuum also involves combinations of chemical pretreatment and (electro) chemical

Intermediate deposition (for example Cu-Ni-Cr multilayers) applied before vacuum coating.

For PTFE surfaces, sputtering treatments with Ar and Cu ions have been shown to cause defluorination and deoxidation of the surface, allowing for bonds between the copper and carbon atoms. Nitrogen, oxygen and hydrogen plasma treatments showed similar results before the copper metallization of PTFE. Again, however, the main mechanism of the layer adhesion of the mechanical anchoring is in microcracks

attributed. Technical applications of PTFE sputter metallization are for PCB metallization (DE 4216940) and for

medical implants (US 5,468,562). Methane plasmas have been used (US Pat. No. 6,057,414), inter alia, for the partial and partial adhesion of copper and gold layers to PTFE surfaces

To achieve deposition of thin carbon layers in the radio-frequency plasma. Sufficiently high adhesion of very thin coatings (~ 50 nm) applied by means of low-temperature CVD to PTFE could be achieved by Breme et al. for titanium carbonitride (F. Breme et al., Thin Solid Films 377, 378 (2000) 755-759) or for Ti, Ta, Nb, Zr, and Hf (DE 10026540). Similar results were reported by Schiller et al. (TL

Schiller et al. / Surface and Coatings Technology 177-178 (2004) 483-488), where very high energy (> 15 kV) pulsed

Carbon ion plasmas have been used in the plasma immersion ion implantation.

It is still not sufficiently reliable possible to coat fluoropolymers adherent.

It is an object of the present invention to provide a way to sufficiently coat fluoropolymers adherent. This object is achieved by a method for the adhesive deposition of a coating on fluoropolymers, a layer arrangement and a device for the adhesive deposition of a coating

Fluoropolymers having the features according to the independent

Claims solved.

According to one embodiment of the present invention, there is provided a method for adherently depositing a coating on a fluoropolymer, the method comprising a fluoropolymer-containing substrate having a carbonaceous (and

hydrogen-containing) layer by means of a plasma in one

Plasma-activated chemical vapor deposition process (PACVD, PECVD) is coated, and the plasma is formed from plasma particles having a mean (for example, kinetic or potential) energy in a range between about 50 eV and about 3000 eV by means of ion source (s). The half-width of the energy distribution can be between about 20 to 400 eV, rising with increasing average energy.

According to another embodiment of the present invention, there is provided an apparatus for adherently depositing a coating on a fluoropolymer, the apparatus comprising a

A coating chamber adapted for coating a fluoropolymer-containing substrate with a carbon-containing layer by means of a plasma, and a controller for forming the plasma from plasma particles having a mean energy in a range between about 50 eV and about 3000 eV

is set up.

According to yet another embodiment of the present invention, there is provided a layer assembly comprising a substrate comprising a fluoropolymer, a carbonaceous coupling layer on the substrate, and a functional layer on the substrate

Adhesive layer has. In the context of this description, the term "adherent-resistant" describes, in particular, a coating which is protected from undesired detachment from the substrate during normal use by a user, and an adhesive coating can therefore be used in particular if a layer arrangement is used as intended the functional layer is protected against unwanted detachment from the adhesion-promoting layer and / or the adhesion-promoting layer from undesired detachment from the fluoropolymer substrate. withstand. When testing the adhesion by crosshatching can be used to check a deposited layer on a

Fluoropolymer substrate a destructive test can be performed in which a grinder through the layer to the cutting device with a cutter

Base material is cut. Subsequently, a tape test is carried out by means of defined adhesive tapes in order to determine solubilizing layer particles.

In the context of this description, the term "fluoropolymer" is understood in particular to mean a polymer, in particular a plastic, which contains fluorine atoms, and a substrate containing a corresponding fluorine atom can be monosubstituted or polysubstituted.

In particular, the term "plasma" is understood to mean an aggregate state in which a gas consists partly or even completely of free charge carriers such as ions or electrons.A partially ionized plasma can be regarded as a mixture of neutral and charged particles, a completely ionized plasma denotes a state of aggregation in which only charged particles are present

PACVD / PECVD process according to an embodiment of the invention technical low-temperature or imbalance plasmas exist. The plasmas can consist of charged ions, neutral particles and energetically excited neutral particles (that is, with kinetic energy or with excited, at higher energy levels

Electrons). The proportion of ionized particles can be between about 5% and 20%. Higher process gas pressures can lead to increased transfer of ionized particles to energetically excited particles by recombination with electrons in the plasma. This process can be used mainly with gridless ion sources (eg, anode-layer-source and end-hall-source types) according to one embodiment of the invention, to achieve neutralized plasmas for material surface modification and coating.

A "plasma of plasma particles with a mean energy of a certain value" is understood in particular to mean a plasma which, at the designated energy value, is or is at its maximum in the

Plasma particle number distribution has. For example, as shown in Figure 2, for a plasma, the energy of plasma particles may be plotted against the number of plasma particles having a corresponding energy, such curve usually having a maximum. This maximum then defines the mean energy of the plasma particles of the plasma in this sense.

The plasma particles may be generated by a plasma source and impinge on the substrate over a large area, thus not focused on a small spot on the substrate. The plasma particles may be from different directions, i. not directed along one

predetermined axis, impinge on the substrate - especially at higher process gas pressures. In particular, a divergence of the plasma particle beam emerging from the plasma source may be +/- 25 ° (determined according to own measurements on anode-layer source ion sources based on the layer thickness distribution

Plasma treatment / coating in hydrocarbon atmosphere).

In particular, the plasma particles may be positively charged and accompanied by electrons, which on average charge the charges

Balancing plasma particles, or - as described above - from the ionized state already in a neutral, but energetic

excited state to have passed. This can be a charge of the (In particular, non-conductive) substrate can be drastically reduced, which for plasma treatment or coating of plastics with long exposure times of the plasma (ie generally> 1 second) may be essential. The plasma particles may exit from an extended region of the plasma source, such as an exit slit or exit slit, which extended region may, for example, have an extent of the order of magnitude of expansion of the substrate.

In particular, the plasma source may not have particle optics for focusing the plasma particles. The plasma source may generate a magnetic field to generate the plasma particles. In particular, the plasma particles may be generated in an anode layer of the plasma source and have energy dependent on a location of production. A half-width of the energy distribution of the plasma particles may be between 10 eV and 400 eV (depending on the average energy, see above). The plasma may in particular contain carbon ions, hydrocarbon ions and / or excited hydrocarbon molecules or carbon hydrogen radicals.

Under an "adhesion layer" is under this

Description particularly understood a layer whose subtask or its sole object is to be arranged between a substrate and an overlying functional layer and a detachment of a functional layer arranged above it from a substrate arranged thereunder by exercising a one-sided or

to avoid double-sided adhesion.

In contrast thereto, a "functional layer" is understood as meaning a layer which provides an actual useful function of a layer arrangement and can be securely fastened to the substrate by means of an adhesion-promoting layer, but does not necessarily have to Such a functional layer is determined by the intended use of the layer arrangement. This can, for example, when using the layer arrangement as a medical implant biocompatible property and an additional

Include property that promotes growth of the implant in the body when inserted into the human body. As a further example of the use of the layer arrangement, components of mechanical and plant engineering as well as parts subject to wear in general can be cited, the functional layer, for example, having low coefficients of friction and / or being highly resistant to wear.

According to one embodiment of the invention, a method for adherent deposition of a coating on fluoropolymers

created, wherein a carbon-containing coating of a

Plasma, generated by ion and / or plasma sources with, for example, about 50 V to about 5000 V potential difference between the cathode and anode (acceleration voltage) is formed. In this case, the plasma particles with, for example, about 50 eV (electron volts) to about 3000 eV of kinetic energy and / or ion energy can be deposited on the fluoropolymer.

According to one embodiment of the invention, a

Plasma pretreatment and a plasma-activated CVD-based

Vacuum coating (PACVD, PECVD) of fluoropolymers under

Application of ion sources for plasma generation with 50 V to 5000 V potential difference between anode and cathode

(Acceleration voltage) and / or average particle energies

(Maximum of the particle energy distribution) between 50 eV and 3000 eV are used to produce the adhesion-promoting layer. By decomposition (dissociation) of gaseous hydrocarbons, but Also of other precursor gases, which are gaseous or liquid at room temperature, but have sufficiently high vapor pressure to form a precursor vapor at the applied working pressure, it can for the deposition of highly adhesive carbonaceous

Coatings on the fluoropolymer surfaces come ("Direct Deposition").

Advantages by using coating processes according to an embodiment of the invention are:

- Simple, cost-effective process management with very simple, low-maintenance and easy-to-operate components (ion and plasma sources, for example anode-layer ion source or end-Hall source)

Very high adhesion, that is almost inseparable connection of the carbon adhesive layer with the fluoropolymer surface (preferably

PTFE)

- highly flexible carbon based coatings, too

Allow bending of films without damage

- High-adhesion coating of fluoropolymers in vacuum coating systems with a large number of inorganic compounds with high purity and low surface roughness

- refrain from any wet chemical pretreatment of

Fluoropolymers such as PTFE before coating, which reduces the associated environmental impact

When using the technique according to an embodiment of the invention, no disadvantages have occurred. Also are the

Investment costs for an ion / plasma source (in particular anode-layer ion sources) in the construction of vacuum coating systems (for example PVD, CVD) with <5-10% of the investment sum very low. By means of suitable process control, contamination of the source by depositing carbon layers can also be largely avoided. In the following, additional embodiments of the method, the device and the layer arrangement will be described. All of the embodiments described below apply to the method as well as to the device and the layer arrangement. A functional layer of the layer assembly may be formed by any vacuum deposition process. In particular, the functional layer can be formed by means of chemical vapor deposition (CVD) .It is also possible to use the functional layer by means of plasma-assisted chemical vapor deposition

To form gas phase deposition ("plasma enhanced chemical vapor deposition", PECVD, or "plasma activated chemical vapor deposition", PACVD). Alternatively, it is possible to use the functional layer by means of

Forming plasma or atomic layer deposition (ALD), the latter being referred to as a modified CVD method for depositing extra-thin layers, Physical Vapor Deposition (PVD) methods may also be used

Vakuumabscheideverfahren be used to form the functional layer, in which case, for example, thermal evaporation method (also called evaporation method),

Electron beam evaporation, pulsed laser deposition (PLD), arc evaporation, molecular beam epitaxy, sputtering, and

Ion beam assisted coating process ("ion beam assisted When using PVD processes for depositing the functional layer, in addition to the substrate to be covered, fluoropolymer with previously applied adhesive interlayer should also be coated with the solid

Target materials placed on the for evaporation or

Sublimation necessary coating equipment, in one

Vacuum container to be placed.

In addition to the aforementioned technologies, the functional layer can be applied in an additional step outside the vacuum coating device, for example with the aid of inkjet printing or other technologies, in a planar or structured manner onto the pretreated fluoropolymer. In particular, the functional layer by means of a

Liquid coating process, such. B. dip coating,

Spincoating, knife coating,

Spray coating to be applied. With these methods, the functional layer can be either over the entire surface or by the use of z. B. one or more masks, ie. exclusively applied to predetermined by the mask locations or areas. For applying the functional layer in a structured manner, i. E. only on predefined locations of the substrate, are still a number of so-called direct structuring. Such

Direct structuring methods are in particular inkjet printing and screen printing, but also gravure, offset printing, etc.

According to a preferred embodiment of the invention, the plasma is formed from plasma particles with an average energy value between 50 eV and 1500 eV. It comes to too small particle energies only to adsorption and condensation processes at one

Solid surface or for incorporation of particles in atomic Surface structures of a solid (metal, glass, ceramic,

Plastic, biological material, etc.) without improving the adhesive properties of the pad. If, on the other hand, too high ion energies are used, the solid state lattice of the substrate can be damaged undesirably. The amount of energy required for a particular solid for adsorption, implantation, etc. generally depends on its physical and chemical composition. In addition, the present inventors have found that, in particular, an energy maximum between 50 eV and 1500 eV, ie the maximum of the energy distribution of a plasma source at one of these values, is particularly advantageous for forming adherent layers on a fluoropolymer substrate.

The present inventors have also found that with an available ion / plasma gun (eg, according to the physical principle of an "end-hall source"), in particular an energy range between 50 eV and 150 eV can be efficiently covered, and that with another ion plasma gun (for example, according to the physical principle of an "anode layer source"), a range between 400 eV and 1500 eV can be efficiently covered. It can be one such example

Ion plasma guns are used. Alternatively, the use of both of these ion plasma guns is possible. More generally, one or more different ion plasma guns may be in one

Coating chamber can be used according to an embodiment of the invention. Depending on the desired properties of a

Network layer or a functional layer arranged thereon in combination with the consideration of the material of

Fluoropolymer substrate thus provides an advantageous energy range of plasma particles to form an adherent coating. In a preferred embodiment, the fluoropolymer-containing substrate may be masked coated with the carbon-containing layer. According to an embodiment, the carbonaceous layer may be formed after, for example, using a mask (eg, shadow mask) or mask layer (eg, masking resist), the substrate has been desirably patterned. After a full-surface deposition of a carbon-containing layer, the mask layer can then be stripped off, for example by stripping, leaving behind a masked layer of the carbon-containing layer, which can then optionally serve as a seed layer for the subsequent growth of an adherent functional layer. After the formation of a structured adhesion-promoting layer, either a functional layer can be deposited over the entire area, which then adheres only to the adhesion-promoting layer to a sufficient and lasting extent, or it can also be deposited before stripping the masking layer and this functional layer, which then of areas outside the structuring this

Masking layer can be removed with the stripping. Thus, according to the invention, even largely chemically inert can be used

Fluoropolymers of an adherent coating are made accessible by a selected energy range is used by the plasma particles. In a corresponding manufacturing process, surface particles can first be removed by elastic shocks. Particles may then be implanted to penetrate the surface, bonding to and in near-surface regions. Activation of the surface may be accomplished, for example, by micro-roughening or by removal of impurities, for example of an organic nature. With a carbon-containing plasma, generated from

Hydrocarbons or organometallic hydrocarbons Precursors, a primer layer can be formed.

Optionally, then a second coating with a

Vakuumabscheideverfahren are formed on the adhesion promoting layer, wherein the adhesion promoting layer can serve as a link between the substrate and the functional layer to be applied.

Optionally, a suitably formed layer arrangement may be subjected to a post-treatment, for example structuring or providing the surface with one or more functional layers. It is also possible to store lubricants, or to polish for example by means of glass bead blasting.

A thickness of the functional layer can be, for example, in a range between 50 nm and 3 mm, in particular between 50 nm and 100 μm, more particularly between 500 nm and 10 μm.

It is possible to dynamically handle the substrate during the plasma treatment, in particular to move it back and forth in a linear manner or in a circular arc in order to achieve a uniform coating. Also, a rotating movement during coating is possible. Thus, during application of the carbonaceous coating, the fluoropolymer workpiece to be coated may either be statically located in front of the ion / plasma source or dynamically moved through the plasma one or more times (many times). The fluoropolymer can be biased with a bias voltage (DC, RF, DC pulsed).

In particular, ion sources are applicable according to the principle of "end-source-source" and "anode-layer-source" ion generation, but it is also possible to use all other non-focused ion sources which generate the required kinetic and ion energies in plasmas can be used. Following there is the possibility of Application of various other vacuum coating methods (for example from the PVD or CVD process group) to the carbon-based adhesive layer then used

Coatings for providing further, for example, functional layer properties. Thus, highly adhesive coatings with layer thicknesses of between 1 nm and 50 μm can be applied to fluoropolymers. Preferably, layer thicknesses of the carbon-containing coating are set between 5 nm and 2000 nm thickness. This application of carbonaceous interlayers directly on the fluoropolymer surfaces by vacuum coating with

Ion sources represents a decisive, advantageous process step.

Ion and plasma sources can be considered as components in vacuum chambers, which have a gas flow (reactive or inert gases) flowing through them through the application of electrical

At least partially ionize potential differences between anodes and cathodes. In many types, ancillary means for neutralizing the ion current are advantageous for allowing interaction of the ion beam with non-electrically conductive surfaces for extended periods of time by preventing the charging of electrical insulator surfaces. This is essential for the treatment of plastics. A variety of different ion and plasma sources can be used, for example Plasmatrons, Kauffmann ion sources, (final) Hall ion sources, Penning ion sources, Saddle Field ion sources, radio frequency and microwave ion / plasma sources.

Electron resonance sources, hollow cathode sources, anode layer ion sources and others. In general, the above examples of ion sources can be categorized into two types: lattice ion sources and latticeless ion sources. Gridless ion sources offer low maintenance and low parts costs, but no ion beam with ions from a narrow energy range compared to ion sources with grid. In the above-mentioned use of gaseous

Hydrocarbons in process gases for ion sources occur at the workpiece surface for the deposition of carbonaceous material

Coatings, which include atoms and molecules from others

Process gases and process gas components may contain (for example, hydrogen). The hydrocarbon can be passed through the source and / or partially dosed after the exit of an ion beam. Such coating processes (so-called "direct coating", "direct deposition") can be used according to the invention particularly advantageously in the abovementioned particle energy range for fluoropolymers technically or scientifically. The advantage of using higher energy hydrocarbon plasmas on fluoropolymer surfaces (and especially on PTFE) is the

Forming a thin defluorinated area (and / or a low fluorine content carbonaceous coating) at / near the surface which reduces the chemical inertness of the fluoropolymer to external agents and therefore chemical

Bonds with the environment allows. Thus, this allows

Surface modification or surface coating a very high adhesion of coatings on fluoropolymers.

The one described as a carbonaceous coating

Surface modification includes the following non-doped and doped hydrogen-containing carbon layers: diamond-like carbon (aC: H ("amorphous hydrogenated diamond-like carbon"), ta-C: H (tetrahedral amorphous hydrogenated diamond-like carbon "), polymeric like carbon, wherein as doping / alloying elements chromium, silicon, titanium,

Tungsten, zirconium, fluorine, phosphorus, oxygen and / or nitrogen,

Application can be found. The content of each of these doping / alloying elements may be between 0 and 50 atomic percent.

Preferably, in addition to non-doped carbon layers, those with silicon and / or nitrogen are used as doping element greater than 0 and less than or equal to 30 atomic percent content.

Advantageous for the direct coating with carbon-based layers is a cleaning or activation of the plastic surface with, for example, Ar and / or O ₂ and / or N ₂ before the treatment step in the hydrocarbon-containing plasma / ion beam. After treatment in the hydrocarbon-containing plasma / ion beam for carbon-based layer deposition, the use of a variety of

Coating technologies or vacuum coating technologies take place in order to apply to the high-adhesion, for example 1 nm to 50 μm thick carbon-containing coatings, further highly adhesive functional surface materials in the same or different layer thickness range. These functional coatings can either be applied directly to the carbonaceous coating or via various intermediate layers (gradient layers,

Multilayer coatings, etc.) are applied to improve the adhesion. The selection of the necessary coating materials includes all chemical elements and compounds, which by means of

Coating process (for example from the field of PVD and CVD coating process) can be applied in stoichiometric and non-stoichiometric chemical composition. In addition, these other coatings can either

Monolayer layers of a single material, gradient layers or multilayer layers of different coating materials (ie, all known PVD and CVD depositable layers in stoichiometric and non-stoichiometric chemical

Composition). The selection of coating technologies applicable to the application of these coatings includes all PVD and CVD coating processes.

The coating adhesion was tested on the fluoropolymers by means of two methods (Scotch tape test / adhesive tape withdrawal test, cross-cut test), in all cases and in both test methods the best possible adhesion values for the carbonaceous coatings alone, but also in combination with coatings deposited thereon after optimization the coating parameters can be detected. Possible geometric shapes of the fluoropolymers for the plasma / ion beam treatment include planar, but also

three-dimensionally shaped substrate materials as general cargo and / or in endless length (belts, films, threads, profiles, textile fabrics, pipes, etc.). The fluoropolymer can be used, for example, as a precursor, intermediate or end product of a production chain.

The surface treatment is appropriate when used

Manipulation devices and / or simultaneously multiple ion sources possible on all sides and can be done in so-called batch coating systems as well as in continuous coating systems.

The fluoropolymer may, for example, belong to one of the following groups: polytetrafluoroethylene (polytetrafluoroethene, PTFE),

Perfluoroalkoxylalkane (PFA), fluorinated ethylene-propylene (FEP), Polyvinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE),

Polyvinyl fluoride (PVF).

The above described method for depositing a coating can be carried out at an absolute pressure between 1 10 ^"5 and 10 mbar with one or more process gases.

These process gases can be provided for the deposition of carbonaceous compounds and are composed of mixtures of inert carrier gases, gaseous / hydrocarbon hydrocarbons as carbon carrier gas and - in the case of doping / alloy - of

Doping / alloy Prekursoren (that is, the corresponding doping elements containing gases) together. All process gases can be supplied to the coating plasma in vapor or gaseous phase. The process gases can be the plasma and / or

Ion source are metered.

The method is performed, for example, with plasma / ion sources having continuous or pulsed mode of operation. Preferably, ion sources of the type (physical principle) "anode layer ion source" and "end-Hall source" are suitable for the described

Layer deposition.

The temperature of the fluoropolymer, for example, is between-150 ° C and + 300 ° C during the coating. To reduce the

Thermal loading of the fluoropolymer may occur during the

Coating this can be optionally cooled. In addition, however, the operation without cooling is possible and is preferably applied. Heating by means of the plasma or by heating elements is also possible. The coating can be applied in all PACVD / PECVD and / or PVD coating systems (batch coating systems as well as continuous coating plants).

Layer arrangements according to exemplary embodiments of the invention can be used for a variety of different applications. For example, the functional layer may be provided as a wear protection layer, for example for hardening surfaces of tools. According to another

Exemplary embodiment, the functional layer may be a biocompatible layer, for example for medical applications or

Applications in pharmacy or microbiology. For

Medical applications, for example, a

Heart valve implant are formed. It is also possible,

According to the invention, to mount a sensor layer as a functional layer on an adhesion-promoting layer, for example for chemosensors, biosensors, temperature sensors, pressure sensors, etc. Such a sensor layer can then be protected against undesired detachment and is therefore also suitable for detecting

Sensor signals in chemically or physically aggressive environments. According to another embodiment, the functional layer may be an electrically conductive layer, for example a structured metal layer for providing desired electrical paths in an electronic component. This electrically conductive layer can then be protected from undesired detachment from the substrate by means of the adhesion-promoting layer and can also be protected by the

carbonaceous primer layer are electrically isolated from the environment. It is also possible that the functional layer is a for Example is optical or electromagnetic reflection layer, such as a mirroring layer for optical applications.

In the following, exemplary embodiments of the

Present invention described in detail with reference to the following figures.

1 shows a cross section of a layer arrangement according to an exemplary embodiment of the invention.

FIG. 2 shows an energy distribution of different particles of a plasma source which can be used for a method and an apparatus according to an exemplary embodiment of the invention (according to [Veeco, Technical Manual ALS340L Anode Layer Source, Fort Collins (CO), 2003]).

FIG. 3 shows a schematic view of a device for the adhesive deposition of a coating on a fluoropolymer according to an exemplary embodiment of the invention. FIG.

The illustrations in the figures are schematic and not to scale.

The same or similar components in different figures are provided with the same reference numerals.

Embodiments of the present invention describe methods of ion treatment and ion assisted vacuum deposition with vacuum ion or plasma sources for applying highly adherent coatings to fluoropolymers. The coatings consist for example of pure, undoped or doped / alloyed, hydrogen-containing carbon in the form of

Diamond-like carbon (a-C: H, ta-C: H) and polymer-like carbon. They may be functional layer and / or adhesive interlayer for further depositable PVD or CVD coatings.

1 shows a cross-sectional view of a layer arrangement 100 according to an exemplary embodiment of the invention.

The layer assembly 100 includes a polymeric substrate 100 that has a fluorine component and is therefore referred to as a fluoropolymer. On the Teflon substrate 100 is a carbonaceous

Adhesive layer 102 applied by means of a

Plasma process is generated with a selected energy of the plasma particles with a maximum or center of gravity of the plasma particle energy between 50 eV and 3000 eV. On the adhesion-promoting layer 102, a functional layer 104 is vacuum-deposited, which may have different technological properties (biocompatible, electrically conductive, wear-resistant, low-friction, sensory-active, etc.). FIG. 2 shows a diagram 200 with an abscissa 202, along which an energy of plasma particles, generated by means of a plasma or ion source, is plotted. Along an ordinate 204 is plotted how many plasma particles of a certain energy are present in a plasma (pond density). The curve 206 schematically shows an energy distribution of a plasma particle ensemble of a plasma or

Ion source and has at a point 208 a global maximum (E _mea n / max) - According to one embodiment of the invention, this maximum 208 is in a range between about 50 eV and about 3000 eV, may be in particular 500 eV. In addition, the energy distribution of the plasma particles ends at a maximum energy of 209 (E _max ). FIG. 3 schematically shows an apparatus for adherently depositing a coating on a fluoropolymer substrate in accordance with FIG

Embodiment of the invention. In FIG. 3, for the sake of clarity, only a part of components is shown which are in such a way

Device may be included.

The apparatus 300 includes a coating chamber 302 configured to coat the fluoropolymer substrate 100 with a carbonaceous layer, shown at 102 in FIG. 1, by means of a plasma or an at least partially ionized gas 306.

A control unit 304 (for example, a microprocessor or a central processing unit) controls the operation of the apparatus 300 and allows plasma particles having an average energy on the order of 300 eV to be used to form the plasma 306. For example, FIG In preliminary tests it is determined with which operating procedure or parameters the components described individually below must be controlled in order to ensure that the maximum (see reference numeral 208) of the energy curve remains within a desired range and, in particular, to determine the maximum of a current energy distribution, the control unit 304 can also perform sensor measurements of energy distribution sensitive parameters in the coating chamber 302. By comparing actual values with, for example, stored in a memory setpoint values, the control 304 determine the current energy maximum and may possibly Readjust control parameters of device 300 to adjust a desired energy maximum.

The interior of the coating chamber 302 may be brought to a desired negative pressure, as measured by pressure sensors 351 in various areas of the apparatus, by means of a single or multi-stage vacuum pumping system 350 controllable by the control unit 304, with control of pressure by a variety of means

Methods (eg pump speed, throttle valve, gas addition, etc.) can be done.

The generation of the plasma (ion current) takes place by means of one or more ion / plasma sources 308 which, in principle, at least partially ionize a gas flowing through the source or a gas located in front of the source by applying electrical voltage. The ion / plasma sources 308 are by one or more

Power supply 310 connected, which

DC, pulsed or alternating current of definable frequency (low frequency, medium frequency, radio frequency, radio frequency) to the ion / plasma sources 308 for exciting gas ionization.

Another power supply 312 may be used to apply

DC, pulsed DC or AC with definable frequency applied to the holder 314 for the substrate 100. A temperature of the holder 314 or the walls and internals of the coating chamber 302 may by means of a

Temperature control unit 316 can be achieved by heating or cooling

The control unit 304 not only controls the temperature control unit 316 as well as the power supply (s) 310, 312 for the ion / plasma source 308 and the substrate holder 314 but also valves 318, the

different process gas containers and / or

Process liquid container 320 (with different process gases and / or process liquids) via gas and / or

Liquid vapor metering 319 connect with the coating chamber 302. The addition of the process gases, process vapors can be controlled via the valves 321 into the ion / plasma source 308, directly into the coating chamber 302 or simultaneously 302 and 308, wherein the outlet openings in the coating chamber 302 can be chosen freely, but it is preferable , reactive

Process gases, if not passed through the ion / plasma source 308 itself, are introduced into the coating chamber 302 near it. By means of an input / output unit 324, a user

communicate bidirectionally with the control unit 304, in particular transmit control signals to the control unit 304 or perceive parameters or results of a coating process via an output screen.

Alternatively to FIG. 3 it is also possible to have several same or

record different plasma generation units or ion sources in one and the same coating system, for example, a first ion gun with a center of gravity 208 in a range between 50 eV and 150 eV and a second ion gun with a center of gravity in the range between 400 eV and 1500 eV.

In addition to the installation of one or more

As an alternative to FIG. 3, it is also possible for plasma generation units or ion sources to use further coating methods from the group of PVD systems. and CVD processes in the same coating chamber in

accommodate different arrangement.

During any of the processes performed, the fluoropolymer substrate (s) charged into the coating chamber 302 on the supports 314 may either remain static or be manipulated dynamically, with certain movements (rotations, linear displacements, etc.) and travel speeds.

In the following, two concrete litigation will be explained.

Example 1: Surface activation and modification of PTFE by means of anode-layer ion source with high-adhesion carbonaceous

coating

PTFE components with a flat or three-dimensional shape (but in this embodiment without undercuts) of a size of 360 mm height and 200 mm width are treated by means of a linear anode layer ion source to apply a high-adhesion carbon coating on one side. After a rough cleaning, the PTFE components are charged in the vacuum chamber and brought to the required starting pressure of the coating between 5-10 ^"6 and 1-10 ^{" 4} mbar by a two-stage pumping system. During coating, the PTFE components are continuously attached to the substrate plate

Coated coating sources along. As a preparatory process step, a cleaning / activation of the PTFE surface by means of

Oxygen-argon plasma generated by the linear anode-layer ion source. In the subsequent main process step becomes

According to the invention, the anode-layer ion source with acetylene (possibly under Addition of argon) acted upon. Depending on the means

Vacuum shifter adjustable pumping capacity of the vacuum pump system, total gas flows between 5 and 40 sccm at a gas flow ratio acetylene: argon = 1: 20 to 1: 0 are applied. Here are pressures between 5- 10 ^"4 and 5- 10 ^{" 2} mbar in the recipient. The operation of the anode-layer ion source is carried out with 500 V to 3000 V potential difference (anode potential) and currents between 2 mA and 1000 mA. After 30 to 60 minutes treatment time (depending on the gas flow) the desired layer thicknesses for the functional application are achieved. The adhesion test of the carbon coatings (aC: H) on the PTFE surfaces by cross hatch test and Scotch tape test shows that it is not possible to remove the carbon layer from the PTFE. Example 2: Surface activation and modification of PTFE by means of anode-layer ion source with high-adhesion carbonaceous

Coating and Subsequent PECVD Coating with High-adhesion Functional Layer Based on the process control described in Example 1, the carbon coating process is stopped by means of the anode-layer ion source after the indicated 30 to 60 minutes treatment time (corresponding for example to 60 nm to 1000 nm layer thickness) and then by means of magnetron sputtering an approximately 1 μηη thick

Functional layer made of titanium or titanium nitride without gradient transition to the intermediate carbon-adhesive layer of PTFE. The

Adhesive strength tests for the overall composite layer show the same good results as described in Example 1. In addition, it should be understood that "having" does not exclude other elements or steps, and "a" or "an" does not exclude a plurality. "Further, it should be noted that features or steps described with reference to one of the above embodiments also can be used in combination with other features or steps of other embodiments described above, and reference signs in the claims are not intended to be limiting.

Claims

Patent claims

A method of adherently depositing a coating on a fluoropolymer, the method comprising:

Coating a fluoropolymer-containing substrate with a carbon-containing layer by means of a plasma;

Forming the plasma from plasma particles with a mean energy in a range between 50 eV and 3000 eV.

2. The method of claim 1, wherein the plasma by means of a

Ion source or by means of a plasma source with between 50 V and 5000 V accelerating voltage between the cathode and anode is generated.

3. The method of claim 1 or 2, wherein the plasma is generated by means of an anode layer ion source or by means of an end Hall ion source.

4. The method of claim 2 or 3, wherein during the coating, the substrate to be coated is located statically in front of the ion source or the plasma source.

5. The method of claim 2 or 3, wherein during coating, the substrate to be coated is dynamically moved once or more times through the plasma.

6. The method according to any one of claims 1 to 5, wherein the coating is deposited on the fluoropolymer as a precursor, intermediate or end product of a production chain.

7. The method according to any one of claims 1 to 6, wherein the coating is carried out at an absolute pressure between 1 - 10 ^"5 mbar and 10 mbar using one or more process gases.

8. The method according to any one of claims 1 to 7, wherein the coating is carried out by means of a mixture of inert carrier gases and gaseous and / or vaporous hydrocarbons as carbon support gas.

9. The method of claim 8, wherein the mixture further doping precursors and / or alloy precursors are added.

10. The method according to any one of claims 1 to 9, wherein the coating is carried out with one or more process gases, which are supplied to the plasma in the vapor phase or gaseous phase.

11. The method of claims 2 and 10, wherein the one or more process gases of the plasma source or the ion source are metered.

12. The method according to any one of claims 1 to 11, wherein the substrate during the coating with an electrical bias

can be applied.

13. The method according to any one of claims 1 to 12, wherein during the coating, the substrate is brought to a temperature between - 150 ° C and + 300 ° C.

14. The method according to any one of claims 1 to 13, wherein the substrate is cooled to reduce the thermal stress during coating.

15. The method according to any one of claims 1 to 14, wherein the substrate remains uncooled during the coating.

16. The method according to any one of claims 1 to 14, wherein the substrate is heated before and / or during the coating.

17. The method according to any one of claims 1 to 16, further comprising forming a functional layer on the layer then serving as an adhesion-promoting layer.

18. The method of claim 17, wherein the functional layer is formed by a vacuum deposition process.

19. The method according to claim 17 or 18, wherein the functional layer by means of chemical vapor deposition, plasma enhanced chemical vapor deposition, atomic layer deposition, plasma activated chemical vapor deposition, plasma polymerization, laser beam evaporation, arc evaporation,

Electron beam evaporation, thermal evaporation,

Molecular Beam Epitaxy, ion beam assisted coating or sputtering is formed.

20. The method of claim 17, wherein the functional layer is formed in a further step outside of the vacuum coating chamber, in particular by means of an inkjet print.

21. The method of claim 17, wherein the functional layer over the entire surface or using a mask by means of a

Liquid coating process is applied, in particular by means of dip coating, spin coating, knife coating, and / or spray coating.

22. The method of claim 17, wherein the functional layer in

structured way only on predefined positions of the

Adhesive layer serving layer is applied to the substrate by means of a Direktstrukturierungsverfahrens, in particular by means of a direct dosing, inkjet printing, screen printing, gravure, and / or offset printing.

23. The method of claim 1, further comprising activating a surface of the substrate prior to coating by treating the substrate with a carbon-free plasma.

24. The method of claim 23, wherein activating means

Treating the substrate in an oxygen and / or argon and / or nitrogen atmosphere takes place.

25. The method according to any one of claims 1 to 24, wherein the plasma of plasma particles having an average energy in a range between 50 eV and 1500 eV, in particular with a mean energy in a range between 50 eV and 150 eV or with an average energy in a range between 400 eV and 1500 eV is formed.

26. The method according to any one of claims 1 to 25, wherein the a

Fluoropolymer-containing substrate is coated with a masked carbon and hydrogen-containing layer.

27. An apparatus for adherently depositing a coating on a fluoropolymer, the apparatus comprising:

a coating chamber used for coating a

Fluoropolymer-containing substrate is arranged with a carbon and hydrogen-containing layer by means of a plasma;

a controller configured to form the plasma from plasma particles having a mean energy in a range between 50 eV and 3000 eV.

28. The apparatus of claim 27, set up as a PVD coating plant, PACVD coating plant, PECVD plant, CVD plant, batch coating plant or continuous

Coating plant. 29. The apparatus of claim 27 or 28, comprising one or more different plasma sources.

Layer arrangement comprising:

a substrate comprising a fluoropolymer;

a carbonaceous adhesive layer on the substrate; a functional layer on the primer layer.

The laminate of claim 30, wherein the fluoropolymer-containing substrate comprises polytetrafluoroethylene, perfluoroalkoxyalkane, fluorinated ethylene-propylene, polyvinylidene fluoride,

Polychlorotrifluoroethylene and / or polyvinyl fluoride comprises or consists thereof.

32. Layer arrangement according to claim 30 or 31, designed as a planar geometric shape, tape, foil, thread, textile fabric, tube, rod or three-dimensional complex shaped component or profile.

33. The layer arrangement according to claim 30, wherein the adhesion-promoting layer is a non-doped carbon-containing layer or a doped carbon-containing layer.

34. Layer arrangement according to one of claims 30 to 35, wherein the adhesion-promoting layer diamond-like carbon, in particular a-C: H

Diamond-like Carbon or ta-C: H Diamond-like carbon, or polymer-like carbon has.

35. A layer arrangement according to any one of claims 30 to 34, wherein the carbonaceous bonding layer with chromium, silicon, titanium,

Tungsten, zirconium, fluorine, phosphorus, oxygen and / or nitrogen is doped as a doping element and / or alloying element.

36. Layer arrangement according to one of claims 30 to 35, wherein a content of each of these individual doping elements and / or

Alloy elements greater than 0 atomic percent and less than or equal to 50

Atomic percent lies.

37. Layer arrangement according to one of claims 30 to 36, wherein the carbonaceous adhesion promoting layer has a layer thickness between 1 nm and 50 μιη, in particular between 5 nm and 2 μηι having.

38. Layer arrangement according to one of claims 30 to 37, wherein the functional layer is applied directly to the adhesion-promoting layer.

39. Layer arrangement according to one of claims 30 to 38, wherein the functional layer is applied by one or more intermediate layers separately on the adhesion-promoting layer.

40. The layer arrangement of claim 39, wherein the one or more intermediate layers comprise a monolayer layer of a single material, a gradient layer and / or a multilayer layer

have different coating materials.

41. The layer arrangement according to one of claims 30 to 40, wherein the

Functional layer is a wear protection layer, a biocompatible layer of a medical implant, a sensor layer, an electrically conductive layer and / or a reflective layer.