DE102015115167A1 - Shaped body comprising a functional layer, process for its preparation and its use - Google Patents

Abstract

The present invention relates to moldings whose surface is at least partially covered with a functional layer, to processes for producing these moldings and to their use; In addition, the present invention relates to systems - in particular tools - containing the shaped body according to the invention, which have improved stability against abrasive forces.

Description

Technical area

The present invention relates to moldings whose surface is at least partially covered with a functional layer, to processes for producing these moldings and to their use; In particular, the present invention relates to tools coated with a plasma polymer functional layer which has a non-sticking effect with respect to the adhesion of adhesives, e.g. so-called hotmelt and dispersion adhesives. In addition, the present invention relates to systems - in particular tools - which have improved stability against abrasive forces.

State of the art

Shaped bodies or objects which have a plasma-polymer functional layer are known from the prior art. So are already in the German publication DE 42 16 999 A1 Objects made of silver which have a so-called plasma-polymer coating.

Due to a gradual variation of the process parameters, the coatings have a layered structure that includes a coupling layer, a permeation-preventing layer and a hard, scratch-resistant surface seal.

To produce the scratch-resistant layer, a mixture of oxygen and hexamethyldisiloxane (HMDSO) is used.

Furthermore, in the German Offenlegungsschrift DE 195 43 133 A1 discloses a method for producing thin, highly hydrophobic polymer layers by plasma polymerization. For plasma polymerization, monomers are vinylmethylsilane and vinyltrimethoxysilane, which are monomers which have at least one group with a low affinity for oxygen and which can be plasma-polymerized with substantial retention of structure.

The monomers mentioned can nichtpolymerisierbare gases such. As noble gases, nitrogen or hydrogen may be added as auxiliary or carrier gases. Such auxiliary or carrier gases serve to improve the homogeneity of the plasma and to increase the pressure in the gas phase.

The disadvantage of in the DE 195 43 133 In particular, the coating disclosed herein can easily be removed from the substrate, as described above.

Furthermore, the German disclosure document DE 197 48 240 A1 Process for the corrosion-resistant coating of metal substrates described by way of plasma polymerization, wherein the metal substrate is first subjected in a first pretreatment step of a mechanical, chemical and / or electrochemical smoothing and in a second process step of plasma activation, before then the actual plasma polymer coating is applied.

Hydrocarbon and / or organosilicon compounds are mentioned as main constituents of the plasma polymer, with the use of hexamethyldisiloxane and hexamethylcyclotrisiloxane being emphasized as being particularly preferred.

Hexamethyldisiloxane is used in the examples of the abovementioned publication, with oxygen and nitrogen being admixed as auxiliary or auxiliary gases.

More detailed information - such as on the ratio of monomers and oxygen - can not be found in this document. In addition, this publication does not disclose how and on which substrate a plasma polymer coating must be applied in order to obtain a particularly easy-to-clean surface.

Description of the invention

The object of the present invention is therefore to provide moldings, in particular tools, with a functional layer or with a functional coating and a process for producing such functionally coated moldings, the coating of which has anti-adhesive properties, in particular with respect to adhesives, for example compared with the so-called hot-melt adhesives or dispersion adhesives. has anti-abrasive properties to minimize downtime that can occur in industrial production for cleaning (removal of adhesive residue) or replacement of damaged or worn tools.

• i. Einbringen und Positionieren des Substrats bzw. Formkörpers in einer ADP-(Atmosphärendruckplasma-), NP-(Niederdruckplasma-) oder in eine PACVD-(Plasma Activated Chemical Vapore Deposition-)Anlage;
• ii. Behandeln des Substrats unter Plasmabedingungen des jeweilig gewählten Plasmas, so dass eine Antihaftbeschichtung mit anti-abrasiven zumindest auf einem Teil der Oberfläche des Substrats/Formkörpers ausgebildet wird.

The object is achieved by a shaped body which can be produced by the following method:

• i. Introducing and positioning the substrate in ADP (atmospheric pressure plasma), NP (low pressure plasma) or PACVD (Plasma Activated Chemical Vapor Deposition) equipment;
• ii. Treating the substrate under plasma conditions of the respective selected plasma, so that an anti-adhesive coating with anti-abrasive at least on a part of the surface of the substrate / molded body is formed.

Plasma technology has established itself in almost all technical areas in recent years. Accordingly, for a variety of embodiments partially extensive state of the art known. In addition to fine cleaning and the activation of surfaces, plasma technology is particularly suitable for modifying surface properties and for coating surfaces - eg with hydrophilic or hydrophobic layers, friction-reducing layers or barrier layers. The latter use is particularly relevant for the solution of the above-mentioned objects underlying the present invention, in terms of the coating of components or tools of various kinds (substrate) relevant.

The plasma-assisted coating method according to the invention can be carried out in particular on the basis of three different process variants, including the low-pressure method (low-pressure plasma NP), the atmospheric pressure method (atmospheric pressure plasma ADP) and the so-called PACVD (plasma-activated chemical vapor deposition) method.

In the low-pressure method, a gas is excited in a vacuum by supplying energy, for example by UV radiation. As a result, in addition to electrons and other reactive particles, high-energy ions are generated that form the plasma. For coating such low pressure plasmas of the glow discharge type are used. Here, in a pressure range of 1-100 Pa diffuse gas discharges of 50-1000 mm expansion are generated. Arc discharges are used in a wide pressure range from low pressure to atmospheric pressure and are generally suitable for producing localized plasmas of a few millimeters in size. By means of these hot regions, the gas to be treated can either be flowed for the conversion of gases or the energy is transported from the sheet to the treatment zone by means of a working gas jet (see atmospheric pressure variant below). With a supply of reactive gases they are decomposed in the discharge area and on surfaces in the environment that may belong to workpieces, the layer deposition takes place. The ionized gas chemically reacts with the surface of the substrate. This allows surfaces to be effectively modified or coated.

In the atmospheric pressure variant, a gas is excited by means of high voltage under ambient pressure in such a way that a plasma ignites. The plasma is expelled from the nozzle using compressed air.

By varying the process parameters - e.g. Treatment speed and distance to the substrate surface - as with the low pressure method, the treatment results can be influenced in different directions.

In plasma generation in the atmospheric pressure range, mainly barrier discharges or corona discharges are used, which make it possible to set a non-thermal energy distribution despite the high impact frequency between electrons and heavy particles. In the case of barrier discharge, the self-turn-off of the discharge introduces energy only during a short time window of about 5-50 ns, while the corona discharge creates a highly inhomogeneous electric field by means of sharp or edged electrodes. In both cases, energy is supplied to the electrons only briefly so that only a few shocks can occur.

Plasma Enhanced Chemical Vapor Deposition (PACVD) is a special form of chemical vapor deposition (CVD) that promotes chemical deposition by plasma. The plasma can burn directly on the substrate to be coated (direct plasma method) or in a separate chamber (remote plasma method). While in the CVD the dissociation (breaking up) of the molecules of the reaction gas by external supply of heat as well as the released energy of the following chemical reactions happens, take over this task in the PECVD accelerated electrons in the plasma. In addition to the radicals formed in this way, ions are also generated in a plasma which, together with the radicals, cause the layer deposition on the substrate. As a rule, the gas temperature in the plasma only increases by a few hundred degrees Celsius, which, in contrast to CVD, can also coat more temperature-sensitive materials.

In the direct plasma method, a strong electric field is applied between the substrate to be coated and a counter electrode, by which a plasma is ignited. In the remote plasma method, the plasma is arranged so that it has no direct contact with the substrate. This provides advantages with respect to selective excitation of individual components of a process gas mixture and reduces the possibility of plasma damage to the substrate surface by the ions. The plasmas can also be produced inductively / capacitively by irradiation of an alternating electromagnetic field.

In the context of the present invention, the use of a low-pressure or atmospheric-pressure plasma is preferred among the given implementation variants, of which the Atmospheric pressure plasma is particularly preferred. Such a plasma can be produced with commercially available devices for the plasma treatment - such as with the system Plasmatreater AS 400 of the manufacturer Plasmatreat GmbH, Steinhagen (DE) - representable.

In the plasma polymerization, vapor-forming organic precursor compounds (precursor or precursor monomers) in the process chamber are first activated by a plasma under the conditions prevailing there. The ionized molecules produced by the activation form first molecular fragments already in the gas phase in the form of clusters or chains. The subsequent condensation of these fragments on the substrate surface then causes polymerization under the influence of substrate temperature, electron and ion bombardment and ultimately results in the formation of a closed layer.

Surprisingly, it has been found that by means of the plasma treatment of moldings-preferably using hydrocarbons and / or siloxanes as precursors-it is possible to obtain coatings on the moldings used which have the desired non-adhesive effect towards adhesives-in particular compared to hotmelt and dispersion adhesives and provide the coated tools with improved protection against abrasive forces.

Among the above-mentioned hydrocarbon precursors, short-chain (1 to 10 carbon atoms) saturated or unsaturated hydrocarbons are preferred, of which methane, ethane and ethyne (acetylene) are particularly preferred.

In addition, among the hydrocarbons, halo-substituted - especially saturated or unsaturated, cyclic, fluoro-substituted - hydrocarbons - e.g. Hexafluoroethane - preferred. Besides, among the cyclic hydrocarbons, octafluorocyclobutane and octafluorocyclopentene are particularly preferable.

Among the siloxanes, poly (dimethylsiloxanes) are preferred, including cyclic siloxanes such as hexamethylcyclotrisiloxane. Among the poly (dimethylsiloxanes), hexamethyldisiloxane is particularly preferred.

Furthermore, it is also possible to use mixtures of the precursors mentioned.

Depending on the particular precursors used, it may be advantageous to use the substrate - i. Shaped body or tool - to heat during the coating.

The gases to be used as process or ionizing gases are also known from the prior art. They include gases or noble gases - such as argon, oxygen and / or nitrogen, or gas mixtures - such as air or compressed air - or forming gas (a gas mixture of 95% nitrogen and 5% hydrogen).

The gas molecules are ionized in the (vacuum) treatment plant, where a plasma is generated by an electric field. The plasma for treating plastics is preferably produced by means of microwave radiation and high-frequency alternating voltage, while in the plasma coating of substrates made of metal preferably a pulsed DC plasma is used.

Examples:

The following exemplary plasma parameters give the plasma conditions for a carbon-based and a siloxane-based coating, respectively:

A) Apparatus parameters

• – Wirkleistung ~300 W (Effektivspannung ~1 kV, Effektivstrom 0,3 A)
• – ~2 Pulse pro Periode, Spitze ~3,8 kV, Pulsbreite ~1,4 µs
• – Tolerante Abweichung ca. +/–25 % (erzielbar mit einer Plasmatreater AS 400 Anlage)
• – Plasma-Spannung: 280 V
• – Plasma-Frequenz: 21 kHz
• – Plasma-Cycle-Time: 10–20 %

Free-jet nozzle made of tungsten and copper, d ~ 4mm Pulsed AC arc discharge (AC arc discharge) with target corridor:

• - Active power ~ 300 W (RMS voltage ~ 1 kV, RMS current 0.3 A)
• - ~ 2 pulses per period, peak ~ 3.8 kV, pulse width ~ 1.4 μs
• - Tolerant deviation approx. +/- 25% (achievable with a Plasmatreater AS 400 system)
• Plasma voltage: 280V
• - Plasma frequency: 21 kHz
• Plasma Cycle Time: 10-20%

B) Exemplary layer formulation for an organic carbon-based layer:

• - Ionizing gas: nitrogen (~ 1500 l / h)
• - precursor: acetylene (~ 38 l / h), 1-point feed
• - Distance nozzle exit substrate: 5-10 mm
• - Surface (meandering) coating with track pitch: 1 4 mm (per layer thickness)
• Jet speed: 5-10 m / min (per layer thickness)
• - Optional: tempering e.g. at 200 ° C for 1.5 h to improve the layer adhesion / immediate use.

C) Exemplary layer formulation for siloxane-based layer:

• - Ionizing gas: compressed air (~ 1500 l / h)
• - Precursor: hexamethyldisiloxane (~ 30 g / h), 1-point feed
• - nozzle exit substrate distance: 5-10 mm;
• - Surface (meandering) coating with track pitch: 1-4 mm (per layer thickness)
• Jet speed: 20-80 m / min (per layer thickness)
• - Optional: tempering e.g. at 200 ° C for 1.5 h to improve the layer adhesion / immediate use.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 4216999 A1 [0002]
• DE 19543133 A1 [0005]
• DE 19543133 [0007]
• DE 19748240 A1 [0008]

Claims (25)

 Shaped article with an antiabrasive non-stick coating against hot melt adhesives and / or dispersion adhesives preparable by treating the uncoated shaped body (substrate) with a plasma based on a pulsed AC (AC) arc discharge in the presence of an organic or silicon-organic precursor preferably selected from a group comprising short-chain hydrocarbons having 1 to 10 carbon atoms and polysiloxanes in the presence of a process or ionizing gas; if appropriate, tempering of the coated molding. Shaped body according to claim 1, characterized in that the shaped body is a tool, preferably a cover device or a sewing knife. Shaped body according to 1 or 2, characterized in that the plasma is a low-pressure plasma or an atmospheric pressure plasma or the coating is carried out with a plasma-assisted chemical vapor deposition. Shaped body according to one of claims 1 to 3, characterized in that the organic precursor is a short-chain saturated or unsaturated aliphatic hydrocarbon precursor, preferably selected from the group comprising methane, ethane and ethyne. Shaped body according to one of claims 1 to 3, characterized in that the organic precursor is a saturated or unsaturated, halogenated hydrocarbon and is preferably selected from the group comprising hexafluoroethane, octafluorocyclobutane and octafluorocyclopentene. Shaped body according to one of claims 1 to 3, characterized in that the silicon-organic precursor is a poly (dimethylsiloxane) and preferably hexamethylcyclotrisiloxane or hexamethyldisiloxane. Shaped body according to one of the preceding claims, characterized in that the ionizing gas is selected from the group comprising oxygen and nitrogen; Gas mixtures, preferably air, compressed air and forming gas; Noble gases, preferably argon. Shaped body according to one of the preceding claims 1-7, characterized in that the treatment of the uncoated shaped body in a plasma treatment device with a tungsten-copper free jet nozzle, with a diameter of ~ 4mm with a pulsed AC arc discharge in a target corridor with an active power of ~ 300 W with an effective voltage of ~ 1 kV and an effective current of 0.3 A with ~ 2 pulses per period at a peak voltage of ~ 3.8 kV and a pulse width of ~ 1.4 μs with a tolerant deviation of +/- 25% and a plasma voltage of 280 V with a plasma frequency of 21 kHz and a plasma cycle time of 10-20%. Shaped body according to claim 8, characterized in that the ionizing gas is nitrogen and is fed into the plasma chamber at a rate of ~ 1500 l / h and the precursor is ethyne (acetylene) entering the plasma space at a rate of ~ 38 l / h wherein the distance from the nozzle exit to the substrate in a range of 5 to 10 mm and a flat, meandering coating with a layer thickness in a range of 1 to 4 mm at a jet speed in a range of 5 to 10 m / min. Shaped body according to claim 8, characterized in that the ionizing gas is compressed air and is fed into the plasma chamber at a rate of ~ 1500 l / h and the precursor is hexamethyldisiloxane, which is fed into the plasma chamber at a rate of ~ 30 g / h , wherein the distance from the nozzle exit to the substrate in a range of 5 to 10 mm and a flat, meandering coating with a layer thickness in a range of 1 to 4 mm at a jet speed in a range of 20 to 80 m / min. Shaped body according to claim 10, characterized in that followed by a heat treatment at 200 ° C over a period of 1.5 h.  A process for producing a shaped article with an anti-abrasive non-stick coating against hot melt adhesives and / or dispersion adhesives according to one of claims 1 to 7, comprising the following method steps Treating the uncoated shaped body (substrate) with a plasma based on a pulsed AC discharge in the presence of an organic or silicon-organic precursor preferably selected from a group comprising short-chain hydrocarbons having 1 to 10 carbon atoms and polysiloxanes in the presence of a process or Ionizing gas; if appropriate, tempering of the coated molding. A method according to claim 12, characterized in that the plasma used in the process is a low pressure plasma or an atmospheric pressure plasma or the coating is carried out with a plasma-assisted chemical vapor deposition. Method according to one of claims 12 or 13, characterized in that the organic precursor is a short-chain saturated or unsaturated aliphatic hydrocarbon precursor having 1 to 10 carbon atoms, preferably selected from the group comprising methane, ethane and ethyne. Method according to one of claims 12 or 13, characterized in that the organic precursor is a saturated or unsaturated halogenated hydrocarbon and is preferably selected from the group comprising hexafluoroethane, octafluorocyclobutane and octafluorocyclopentene. Method according to one of claims 12 or 13, characterized in that the silicon-organic precursor is a poly (dimethylsiloxane) and is preferably hexamethylcyclotrisiloxane or hexamethyldisiloxane. Method according to one of the preceding claims 12 to 16, characterized in that the ionizing gas is selected from the group comprising oxygen, nitrogen; Gas mixtures; preferably air, compressed air, forming gas; Noble gases, preferably argon. Method according to one of the preceding claims 12-18, characterized in that the treatment of the uncoated shaped body in a plasma treatment apparatus with a tungsten-copper free jet nozzle, with a diameter of ~ 4mm with a pulsed AC arc discharge) in a target corridor with an active power of ~ 300 W with an effective voltage of ~ 1 kV and an RMS current of 0.3 A with ~ 2 pulses per period at a peak voltage of ~ 3.8 kV and a pulse width of ~ 1.4 μs with a tolerant deviation of +/- 25 % and a plasma voltage of 280 V with a plasma frequency of 21 kHz and a plasma cycle time (plasma cycle time) of 10-20%. A method according to claim 18, characterized in that the ionizing gas is nitrogen and is fed into the plasma chamber at a rate of ~ 1500 l / h and the precursor is acetylene which is fed into the plasma chamber at a rate of ~ 38 l / h , wherein the distance from the nozzle exit to the substrate in a range of 5 to 10 mm and a flat, meandering coating with a layer thickness in a range of 1 to 4 mm at a jet speed in a range of 5 to 10 m / min. A method according to claim 18, characterized in that the ionizing gas is compressed air and fed into the plasma chamber at a rate of ~ 1500 l / h and the precursor is hexamethyldisiloxane fed into the plasma chamber at a rate of ~30 g / h. wherein the distance from the nozzle exit to the substrate in a range of 5 to 10 mm and a flat, meandering coating with a layer thickness in a range of 1 to 4 mm at a jet speed in a range of 20 to 80 m / min. Shaped body according to claim 20, characterized in that a heat treatment at 200 ° C over a period of 1.5 h.  System comprising a shaped body according to one of claims 1 to 11. A system according to claim 22, characterized in that the system is embodied by a press laminating tool or a sewing machine.  Use of a shaped article according to one of claims 1 to 11 for press lamination or for making seams.