EP1414589A2

EP1414589A2 - Scratch-resistant finish for coated substrates

Info

Publication number: EP1414589A2
Application number: EP02726199A
Authority: EP
Inventors: Peter Betz; Guido Grundmeier; Martin Stratmann
Original assignee: Voestalpine Stahl GmbH; Friedrich Alexander Univeritaet Erlangen Nuernberg FAU; ThyssenKrupp Stahl AG
Current assignee: ThyssenKrupp Steel Europe AG
Priority date: 2001-03-24
Filing date: 2002-03-21
Publication date: 2004-05-06
Anticipated expiration: 2022-03-21
Also published as: DE10114469A1; WO2002076635A3; ES2286251T3; DE50210168D1; EP1414589B1; WO2002076635A2; AU2002256696A1; ATE362405T1

Abstract

The invention relates to use of plasma polymerisation and plasma polymers for the scratch-resistant finishing of coated substrates, a method for the production of a scratch-resistant finish on a coated substrate by application of at least one scratch-resistant layer on the coated substrate by plasma polymerisation and a coated substrate with a scratch-resistant finish, comprising at least one layer made from a plasma polymer produced by plasma polymerisation as outermost layer.

Description

Scratch resistant equipment for coated substrates

description

The present invention relates to the new use of plasma polymerization and plasma polymers for the scratch-resistant treatment of coated substrates. In addition, the present invention relates to a new process for producing a scratch-resistant finish on a coated substrate by applying at least one scratch-resistant layer on the coated substrate by plasma polymerization. Furthermore, the present invention relates to new scratch-resistant coated substrates with at least one layer of a plasma polymer produced by plasma polymerization as the top layer.

The production of layers of plasma polymers on metallic substrates by plasma polymerization of suitable compounds is from the dissertation by G. Grundmeier, "Interface chemical and corrosion analysis of plasma polymer coatings on steel", Technical Faculty of the University of Erlangen-Nümberg, 1997, the patent EP 0 533 606 B. 1, EP 0 619 847 B1 or EP 0 515 373 B2 or from the articles by Tinghaσ F. Wang et al., "Corrosion protection of cold rolled steel by low temperature plasma interface engineering", ,iProgress in Organic Coatings, volume 28 , Pages 291 to 297, 1996, by MP Bonnar, B. M Burnside, A. Little, RL Reuben and JIB Wilson, "Plasma Polymer Films for Dropwise Condensation of Steam", Chemical Vapor Deposition, 1 97, volume 3, booklet A , Pages 201 to 207, or by G. Grundmeier and M. Stratmann, "Plasma polymerization - a new and promising way for the corrosion protection of steel", Materials and Corrosion, volume 49, pages 150 to 160, 1998.

These plasma polymer layers are mainly used for the corrosion protection of the metal surfaces. The question of whether the plasma polymer layers are scratch-resistant in this context, because the layers are overlaid with other coatings (see the above-mentioned dissertation by Grundmeier).

The scratch resistance of coatings on substrates often leaves much to be desired. Insufficient scratch resistance leads to unsightly protective and / or decorative coatings.

Problems of scratch resistance are of great economic and aesthetic importance, especially in automotive painting, especially car painting.

On the one hand, fully painted vehicle bodies can be scratched during final assembly in the factory, for example if test cards are pushed over the bonnet or the bodies are accidentally touched by the fitter. These, albeit often only slight, scratches are particularly unpleasant in bright light, especially in brand new cars.

Furthermore, there are so-called wash scratches in car wash systems, especially with dirty wash water, which are particularly noticeable in the sunshine.

The automotive industry is therefore striving to get the problem of insufficient scratch resistance by using scratch-resistant paints under control.

One possibility is to coat the series coatings with a so-called scratch-resistant sealer based on sol-gel clearcoats, as described, for example, in patent applications DE 43 03 570 A1, De 34 07 087 A1, DE 40 11 045 A1, DE 40 25 215 A 1, DE 38 28 098 A 1, DE 40 20 316 A 1 or DE 41 22 743 A 1 are known. These sol-gel clearcoats or the layers produced from them are also considered organically modified by experts Ceramic materials called. One of their main areas of application is the scratch-resistant finishing of glasses or visors of motorcycle helmets.

However, the known scratch-resistant finishes based on sol-gel clearcoats have a low solids content, which inevitably involves a high solvent content. This high solvent content is questionable and disadvantageous for reasons of safety and environmental protection. The known scratch-resistant finishes usually have a dry layer thickness of 10 μm. They have a sufficient overall visual impression (appearance). With this layer thickness, there are generally only comparatively minor problems of adhesion between the scratch-resistant finish and the coating beneath it. However, if one wants to further improve the scratch resistance and further reduce the dry layer thickness, for example to 3 to 5 μm, the appearance deteriorates.

The object of the present invention is to provide a new scratch-resistant finish for coated substrates, in particular painted car bodies, especially painted car bodies, which no longer has the disadvantages of the prior art, but also reliably protects the coated substrates even in a thin layer Protects scratches and has a good appearance and adheres firmly to the coatings. In addition, the new scratch-resistant finish should be able to be produced in a simple manner, without solvents and without a large amount of material, and should have a very good appearance.

Accordingly, the new use of plasma polymerization and plasma polymers for the scratch-resistant treatment of coated substrates has been found, which is referred to below as "use according to the invention".

In addition, the new method of making scratch-resistant equipment on a coated substrate by depositing at least one scratch-resistant Plasma polymer layer found on the coated substrate by plasma polymerization, which is referred to below as the “inventive method”.

Last but not least, the new scratch-resistant coated substrate with at least one layer of a plasma polymer produced by plasma polymerization was found as the top layer, which is referred to below as the "substrate according to the invention".

In view of the prior art, it was surprising and unforeseeable for the person skilled in the art that the object on which the present invention was based could be achieved with the aid of the use according to the invention. This was all the more surprising since the plasma polymer layers had hitherto been applied directly to this only for the purpose of protecting against corrosion or for modifying metallic surfaces.

The method according to the invention is based on a coated substrate.

Suitable substrates are all those which allow the deposition of plasma polymers and are not damaged by the reaction conditions used.

Electrically conductive and non-conductive substrates are equally possible.

The electrically conductive substrates can be plastic parts which have been made conductive with the aid of electrically conductive pigments or with the aid of an electrically conductive layer thereon, for example made of a metal or a ceramic layer. Furthermore, it can be substrates made of electrically conductive ceramic materials. Metallic substrates are preferably used. Examples of suitable metals to be used according to the invention are titanium, iron, cobalt, nickel, magnesium, aluminum, zinc or their alloys with one another or with other suitable metals such as copper, vanadium, tungsten, molybdenum, chromium, manganese or tin. According to the invention, such metals are advantageous which are usually used in automobile construction for the production of bodies. They are therefore preferred. Examples of suitable metals of this type to be used according to the invention are steels, in particular cold-rolled steels and metal-coated steel sheets.

The electrically non-conductive substrates are those made from conventional and known insulators such as plastics, in particular in the form of foils, glass or ceramic materials. In contrast to the electrically conductive substrates, other excitation frequencies are required here, for example in the microwave range. that is, a microwave plasma is used.

In and of itself, the substrate can have any shape, for example the shape of a fender, a car door, a hood or a trunk lid. According to the invention, it is advantageous if the substrate is planar and in particular is in the form of a sheet or strip.

The thickness of the substrate can vary widely and depends on the particular intended use of the substrate according to the invention. Thicknesses of 0.05 mm to 10 mm, as are usually used in automobile construction, are advantageous.

The substrate is coated, ie there is at least one paint film and / or at least one paint on it. The coating serves to protect the substrate against corrosion, the absorption and dissipation of mechanical energy, the clear coat and / or the coloring and / or effect.

Examples of suitable coatings with an anti-corrosion effect are electrochemically deposited electro-dip coatings, as described, for example, in Japanese Patent Application 1975-142501 (aanic laid-open publication JP 52-065534 A 2, Chemical Abstracts Section No. 87: 137427) or in the patents and applications US 4,375,498 A, US 4,537,926 A, US 4,761,212 A, EP 0 529 335 A 1, DE 41 25 459 A 1, EP 0 595 186 A 1, EP 0 074 634 A 1, EP 0 505 445 A 1, DE 42 35 778 A 1, EP 0 646 420 A1, EP 0 639 660 A1, EP 0 817 648 A1, DE 195 12 017 C1, EP 0 192 113 A2, DE 41 26476 A1 or WO 98/07794.

Examples of suitable coatings for absorption and dissipation of mechanical energy are filler coatings and

Stone chip protection primers as described, for example, in patent applications and patents EP 0427028 A1, DE 41 42 816 A1, DE 38 05 629 C1, DE 31 08 861 C2 or DE 195 04 947 AI.

Examples of suitable coloring and / or effect coatings are solid-color topcoats or basecoats, as described, for example, in patent applications EP 0 089 497 A1, EP 0 256 540 A1, EP 0 260 447 A1, EP 0 297 576 A1, WO 96 / 12747, EP 0 523 610 A1, EP 0 228 003 A1, EP 0 397 806 A1, EP 0 574417 A1, EP 0 531 510 A1, EP 0 581 211 A1, EP 0 708 788 A1 , EP 0 593 454 A1, DE-A-43 28 092 A1, EP 0 299 148 A1, EP 0 394737 A1, EP 0 590 484 A1, EP 0 234 362 A1, EP 0 234 361 A1 , EP 0 543 817 A 1, WO 95/14721, EP 0 521 928 A 1, EP 0 522420 A 1, EP 0 522419 A 1, EP 0 649 865 A 1, EP 0 536712 A 1, EP 0 596 460 A 1, EP 0 596461 A1, EP 0 584 818 A1, EP 0 669 356 A1, EP 0 634 431 A1, EP 0 678 536 A1, EP 0 354 261 A1, EP 0 424 705 A1, WO 97/49745, WO 97/49747, EP 0 401 565 A1, EP 0 A96 205 A1, EP 0 358 979 A. 1, EP 469 389 A1, DE 24 46 442 A1, DE 34 09 080 A1, DE 195 47 944 A1, DE 197 41 554 A1 or EP 0 817 684, column 5, lines 31 to 45, in Be described in detail.

Examples of suitable clearcoats are those which are produced from single- or multicomponent clearcoats, powder clearcoats, powder slurry clearcoats, UV-curable clearcoats or sealers, as described in patent applications, patent specifications and publications DE 42 04 518 A1, EP 0 594 068 A1, EP 0 594 071 A1, EP 0 594 142 A1, EP 0 604 992 A1, EP 0 596 460 A1, WO 94/10211, WO 94/10212, WO 94/10213, WO 94/22969 or WO 92 / 22615, US 5,474,811 A 1, US 5,356,669 A 1 or US 5,605,965 A 1, DE 42 22 194 A 1, BASF Lacke + Farben AG, "Powder Coatings", 1990, BASF Coatings AG "Powder Coatings, Powder Coatings for Industrial Applications", January 2000 , US 4,268,542 A1, DE 195 40 977 A1, DE 195 18 392 A1, DE 196 17 086 A1, DE-A-196 13 547, DE 196 52 813 A1, DE-A-198 14471 A1 , EP 0 928 800 A1, EP 0 636 669 A1, EP 0 410 242 A1, EP 0 783 534 A1, EP 0 650 978 A1, EP 0 650 979 A1, EP 0 650 985 A1, EP 0 540 884 A1, EP 0568 961 A1, EP 0054505 A1, EP 0 002 866 A1, DE 197 09 46 7 A1, DE 42 03 278 A1, DE 33 16 593 A1, DE 38 36 370 A1, DE 24 36 186 A1, DE 20 03 579 B1, WO 97/46549, WO 99/14254, US 5,824,373 A, US 4,675,234 A, US 4,634,602 A, US 4,424,252 A, US 4,208,313 A, US 4,163,810 A, US 4,129,488 A, US 4,064,161 A, US 3,974,303 A, EP 0 844286 A 1, DE 43 03 570 A 1, DE 34 07 087 A1, DE 40 11 045 A1, DE 40 25 215 A1, DE 38 28 098 A1, DE 40 20 316 A1 or DE 41 22 743 A1 are known.

Examples of suitable lacquer films can be found in patent applications WO94 / 09983 A, EP 0 361 823 A1, DE 195 35 934 A1, DE 195 17 069 A1, DE 195 17 067 A1 or 195 17 068 A1 or the publications by E. Bürkle in Kunsstoffe 87 (1997), 320-328; Modern Plastics International Volume 11, 1991, 33-34, or by G. Steinbichler and J. Gießauf in Kunststoffe 87 (1997), 1262-1270. In the context of the method according to the invention, the coatings described above are preferably pretreated with an oxidizing plasma. The pretreatment is used to clean and activate the surface of the coatings. Examples of suitable oxidizing agents for generating the oxidizing plasma are fluorine, chlorine or oxygen, in particular oxygen. The oxidizing plasma can also contain noble gases and / or nitrogen.

The conditions of the pre-treatment can vary widely and depend on the requirements of the individual case. In particular, the pressure used in the plasma, depending on the material composition, can be up to 1 bar.

In the oxygen plasma, partial pressures of 0.01 to 3, preferably 0.02 to 2.5, particularly preferably 0.03 to 2, very particularly preferably 0.04 to 1.5 and in particular 0.05 to 1 mbar, are preferred from 200 to 800, preferably 210 to 750, particularly preferably 220 to 700, very particularly preferably 230 to 650 and in particular 240 to 600 V, current intensities from 0.1 to 5, preferably 0.2 to 4.8, particularly preferably 0, 3 to 4.4, very particularly preferably 0.4 to 4.2 and in particular 0.5 to 4 mA, volume flows from 0.1 to 3, preferably 0.2 to 2.8, particularly preferably 0.3 to 2, 4, very particularly preferably 0.4 to 2.2 and in particular 0.5 to 2 st. cm3 / min and frequencies of 0.1 to 3, preferably 0.2 to 2.7, particularly preferably 0.3 to 2.3, very particularly preferably 0.4 to 2 and in particular 0.5 to 1.5 kHz applied ,

In the further course of the method according to the invention, at least one, preferably one, layer of at least one plasma polymer is deposited by plasma polymerization on the preferably cleaned and activated surface of the coatings. A wide variety of organic and inorganic compounds can be used for plasma polymerization. According to the invention, it is advantageous to use at least one organic compound.

In the context of the present invention, organic compounds, in particular organometallic compounds, are compounds in which at least one element other than carbon is linked to organic radicals, such as substituted or unsubstituted alkyl, cycloalkyl and / or aryl radicals, which may also contain heteroatoms.

Suitable organometallic compounds are organometallic compounds of metals from the subgroups of the Periodic Table of the Elements. Examples of suitable elements are scandium, yttrium, lanthanum, the lanthanides, titanium, zirconium, hafnium, vanadium, niobium, chromium, tungsten, manganese, iron, cobalt, nickel, copper or zinc. The organometallic compounds can contain one or more metal atoms in the molecule. If they contain several metal atoms in the molecule, they can be one and the same metal or at least two different metals.

Other suitable organic compounds are organic compounds of metals and non-metals of the main groups of the Periodic Table of the Elements. Examples of suitable metals and non-metals are boron, aluminum, gallium, indium, silicon, germanium, tin or phosphorus. Silicon is particularly well suited.

Further suitable element-organic compounds are organic compounds which contain at least one of the abovementioned metals of the subgroups of the periodic system of the elements and at least one of the abovementioned metals or non-metals of the main groups of the periodic system of the elements. According to the invention, it is advantageous to use organic silicon compounds such as hexamethyldisilane or hexamethyldisiloxane, in particular hexamethyldisilane.

The organic compounds of silicon preferably used according to the invention can also contain at least one further of the above-described elemental compounds in minor amounts.

In the context of the present invention, “and subordinate amounts” are to be understood here and below as amounts which vary the property profile of the plasma polymer layer in an advantageous manner but do not determine its basic properties.

Furthermore, the above-described elemental organic compounds to be used according to the invention may contain purely organic compounds in minor amounts. Polymerizable organic compounds are preferably used. Examples of suitable polymerizable organic compounds are olefins and acetylenes, in particular olefins such as cyclohexene.

The plasma polymerization of the compounds described above can be carried out in the presence of at least one oxidizing agent. Examples of suitable oxidizing agents are those described above.

In addition, the plasma polymerization can be carried out in the presence of at least one noble gas, in particular argon.

From a methodological point of view, plasma polymerization has no special features, but can be carried out according to the methods and with the aid of the devices as described in the patents, patent applications and publications listed at the beginning.

The plasma polymerization is preferably carried out for 10 minutes to 3 hours, preferably 15 minutes to 2.5 hours, particularly preferably 20 minutes to 2 hours and 15 minutes, very particularly preferably 30 minutes to 2 hours and in particular 40 minutes to 1.5 hours. Partial pressures of elemental organic compound of 0.001 to 0.2, preferably 0.002 to 0.18, particularly preferably 0.003 to 0.16, very particularly preferably 0.004 to 0.14 and in particular 0.005 to 0.12 mbar, if used, are preferably partial argon pressures from 0.01 to 2, preferably 0.02 to 1.8, particularly preferably 0.03 to 1.6, very particularly preferably 0.04 to 1.4 and in particular 0.0 to 1 mbar, if used, oxygen partial pressures of 0.001 to 0.2, preferably 0.002 to 0.18, particularly preferably 0.003 to 0.16, very particularly preferably 0.004 to 0.14 and in particular 0.005 to 0.12 mbar, tensions of 200 to 800, preferably 210 to 750, particularly preferably 220 to 700, very particularly preferably 230 to 650 and in particular 240 to 600 V, current intensities from 0.1 to 5, preferably 0.2 to 4.8, particularly preferably 0.3 to 4.4, very particularly preferably 0, 4 to 4.2 and in particular 0.5 to 4 niA, volume flows from 0.1 to 3, preferably 0.2 to 2.8, particularly preferably 0, 3 to 2.4, very particularly preferably 0.4 to 2.2 and in particular 0.5 to 2 st. cm3 / min and frequencies from 0.1 to 10, preferably 0.2 to 9, particularly preferably 0.3 to 8, very particularly preferably 0.4 to 7 and in particular 0.5 to 6 kHz.

The deposited plasma polymer layer is preferably 0.001 to 10, preferably 0.01 to 9, particularly preferably 0.1 to 8, very particularly preferably 0.5 to 7 and in particular 1 to 6 μm thick.

The composition of the plasma polymer layer can be homogeneous or it can change vertically in different ways. For one, it can

Concentration of a component within the plasma polymer layer decrease or increase continuously or discontinuously. When the concentration of functional groups varies in a targeted manner, the plasma polymer is called “gradient plasma polymer”. This gradient plasma polymer is distinguished by the fact that it has special functional groups at the coating / plasma polymer phase boundary, for example organosilicon-functional groups Interfaces optimize the adhesion, which leads to optimal stability of the scratch-resistant finish, but the plasma polymer layer can also consist of layers of different compositions.

The plasma polymer layer according to the invention or the coated substrates provided with it with a scratch-resistant finish are of very good optical quality (appearance), so that they can also be used for the scratch-resistant coating of automobiles in the luxury class. The scratch-resistant finish according to the invention adheres extremely firmly to the coated bodies and shows no damage or flaking even under mechanical influence. It is weather-stable and chemical-stable and is not attacked by bird droppings. The motor vehicles equipped in a scratch-resistant manner according to the invention therefore have a particularly long service life and a particularly high utility value.

example

The production of a scratch-resistant finish according to the invention by plasma polymerization

A body panel that is coated in the usual and known manner with a cathodically deposited electrodeposition coating, a filler, a metallic

Basecoat and a clearcoat was coated in a plasma reactor, which has an evacuable glass bell with internal electrodes, Gas metering systems and a high vacuum pump included, placed on a grounded electrode.

The painted surface of the body panel was cleaned with an oxygen plasma for 5 minutes at an oxygen partial pressure of 0.3 mbar, a voltage of 400 V, a current of 2 mA and a volume flow of 1.5 hours. cm ³ / min and a frequency of 1 kHz pretreated.

The plasma polymer was heated for one hour at an argon partial pressure of 0.2 mbar, an oxygen partial pressure of 0.05 mbar and a hexamethyldisilane partial pressure of 0.05 mbar, a voltage of 400 V, a current of 1 mA and a volume flow of 1. 5 st. cm ³ / min and a frequency of 4 kHz.

The plasma polymer layer was 3 μm thick. It stuck to the paintwork. Delamination was also not observed after exposure to a constant condensation climate. The plasma polymer layer was highly scratch-resistant and could be used under the usual and known conditions of the brush test (cf. P. Betz and A. Bartelt, Progress in Organic Coatings, 22 (1993), pages 27-37, in particular Fig. 2, page 28; Weight: 2000 g instead of 280 g) are not damaged. It was therefore particularly suitable as scratch-resistant equipment. The scratch-resistant finish and the paint had an overall good visual impression.

Claims

Scratch-resistant equipment for coated substrates

1. Use of plasma polymerization and plasma polymers for the scratch-resistant treatment of coated substrates.

2. A method for producing a scratch-resistant finish on a coated substrate by applying at least one scratch-resistant layer on the coated substrate, characterized in that the scratch-resistant layer is deposited by plasma polymerization.

3. Scratch-resistant coated substrate with at least one layer of a plasma polymer produced by plasma polymerization as the top layer.

4. The use according to claim 1, the method according to claim 2 and the substrate according to claim 3, characterized in that the coating on the substrate comprises at least one paint film and / or at least one coating.

5. The use according to claim 1 or 4, the method according to claim 2 or 4 and the substrate according to claim 3 or 4, characterized in that the coating on the substrate to protect against corrosion, absorption and dissipation of mechanical energy, clear coating and / or the coloring and / or effect is used.

6. The use according to one of claims 1, 4 or 5, the method according to one of claims 2, 4 or 5 and the substrate according to one of claims 3 to 5, characterized in that the coating on the

Substrate is pretreated with an oxidizing plasma. The use, the method and the substrate according to claim 6, characterized in that an oxygen plasma is used as the oxidizing plasma.

The use according to one of claims 1 or 4 to 7, the method according to one of claims 2 or 4 to 7 and the substrate according to one of claims 3 to 7, characterized in that at least one organic compound is used for plasma polymerization.

9. Use, method and substrate according to claim 8, characterized in that at least one organometallic compound of metals of the subgroups of the periodic table of the elements, at least one organic compound of metals and non-metals of the main groups of the element organic compound

Periodic system of the elements and / or at least one organic compound which contains at least one metal of the subgroups and at least one metal or non-metal of the main groups of the periodic system of the elements is used.

10. Use, method and substrate according to claim 9, characterized in that at least one silicon compound is used as the element organic compound.

11. Use, method and substrate according to claim 10, characterized in that hexamethyldisilane is used as the silicon compound

12. Use according to one of claims 1 or 4 to 11, method according to one of claims 2 or 4 to 11 and substrate according to one of the

Claims 3 to 11, characterized in that the Plasma polymerization is carried out in the presence of an oxidizing agent and / or a noble gas.

13. Use, method and substrate according to claim 23, characterized in that oxygen as the oxidizing agent and as noble gas

Argon is used.