EP3700982A1

EP3700982A1 - Primer coating agent system for plastic substrates

Info

Publication number: EP3700982A1
Application number: EP18789668.3A
Authority: EP
Inventors: Audree Andersen; Miao Wang; Kai-Michael WUENNEMANN; Julia Melzer; Jens Lueckert; Frederik Foelling; Peter Machaczek; Igor MILLBAIER; Marc Baeuerle; Andreas Janssen; Tanja Bricke; Tobias Wolf; Thomas Focke
Original assignee: BASF Coatings GmbH
Current assignee: BASF Coatings GmbH
Priority date: 2017-10-23
Filing date: 2018-10-23
Publication date: 2020-09-02
Also published as: KR20200072533A; MX2020004125A; US20200299519A1; JP2021500443A; CA3079082A1; WO2019081461A1; JP7420711B2; US11591479B2; CN111263792A

Abstract

The invention relates to a use of a primer coating agent composition which can be obtained by combining at least two components (A) and (B) of a coating agent system which differ from one another and are present separately from one another, component (B) being non-aqueous, contains at least one polyisocyanate having more than two free isocyanate groups, at least one organic solvent and also at least one Si-containing compound which has at least one hydrolysable radical and at least one non-hydrolysable organic radical, for at least partial application to at least one optionally pretreated surface of a plastic substrate. The invention further relates to a method for producing a corresponding coating on such a substrate and to a method for at least partial coating of at least one surface of a plastic substrate with a multi-layer coating.

Description

Primer Coating System for Plastic Substrates

The present invention relates to a use of a primer coating composition obtainable by combining at least two mutually different and separate components (A) and (B) of a coating agent system, wherein component (B) is non-aqueous, at least one polyisocyanate with more than two free isocyanate groups, at least one organic solvent and further at least one Si-containing compound having at least one hydrolyzable group and at least one non-hydrolyzable organic radical for at least partially applying to at least one optionally pretreated surface of a plastic substrate , a method for producing a corresponding coating on such a substrate and a method for at least partially coating at least one surface of a plastic substrate with a multi-layer coating.

State of the art

Plastics have prevailed in the context of vehicle painting as materials for vehicle parts, vehicle attachment parts and vehicle accessories both indoors and outdoors. Plastics as well as other materials for decorative reasons (for example, color and / or effect) and / or due to technical expediency (for example, light and / or weather resistance) coated with appropriate coating compositions and painted.

To protect the plastics, a primer coating is usually first applied to prepared (pretreated) surfaces of the plastics. This base coat, obtained by applying a corresponding primer to the plastic, then usually constitutes the first coat of a multi-coat finish which is applied to the plastic substrate to achieve the aforementioned decorative and / or technical usefulness. Coating compositions which can be used as primers, in particular as water-based primers, are disclosed, for example, in US Pat. No. 4,720,528 and JP 2008-031453 A1. US Pat. No. 4,720,528 describes coating compositions containing caprolactone-modified acrylic polymers, acrylic microgels and melamine resins. These compositions can be used inter alia for the coating of plastic substrates. JP 2008-031453 A1 discloses coating agents which can be used as primers and which necessarily contain polyolefin resins modified with acid groups.

Usually, primers are applied to the plastic substrate in a separate coating operation before the actual coating with the remaining part of the multi-layer coating and cured. The multi-layer coating usually includes - in addition to primer - at least one color and / or effect basecoat and an overlying clearcoat. Basecoat and clearcoat are either applied separately and cured, or each applied in a wet-on-wet process and then cured both layers together (2C1 B process). The implementation of an upstream and separate process step for applying the primer is for economic reasons, namely due to a higher time and cost, disadvantageous. In particular, the separately to be performed step of curing of the primer and the associated involvement of an upstream separate furnace to achieve this cure for these reasons are undesirable, especially as part of an OEM series coating of plastic substrates to be coated as in the field of automotive OEM.

In order to overcome the disadvantages associated with a separate step of applying the primer, methods are already known from the prior art, which provide for incorporation of the primer application in the wet-on-wet process. In these processes, both primer and basecoat as well as clearcoat are applied by means of a wet-on-wet process and all three layers are subsequently cured together (3C1 B process). Such 3C1 B processes for coating substrates, such as plastic substrates, are known, for example, from US 2010/0152336 A1, WO 2015/114989 A1 and US Pat 2006/0257671 A1 and known. A corresponding 4C1 B process using two different basecoats is also known from JP 20 2-000570 A.

Further, such 3C1B methods for coating plastic substrates are known from US 2007/0190311 A1, US 2011/0070450 A1, US Pat. No. 5,747,114, EP 1 958 982 A2 and EP 2 087 944 A1:

US 2007/0190311 A1 and US 2011/0070450 A1 describe 1K primer coating compositions based on organic solvents. However, the use of such primers is undesirable and disadvantageous, at least for ecological reasons. US 2006/0257671 A1 discloses 1 K primer coating compositions which contain silane-functional non-polar polymers, such as corresponding silane-functional polyolefins. U.S. Patent No. 5,747,114 discloses physically drying primer coating compositions based on polyurethanes and / or oligomeric urethanes, but which are chemically designed so that they are not capable of chemical crosslinking at temperatures of 60 to 110 ° C. In addition, 1K primers often have the disadvantage over 2K primers that adequate crosslinking is not always achieved, and primers or multicoat systems based thereon do not always have the desired application-technological properties, for example with regard to their required weathering properties. Furthermore, 2K primers can be better dosed than standard 1K systems, especially in the series production line.

EP 1 958 982 A2 discloses a 3C1 B process which provides for the sequential application of a waterborne primer coating agent, a basecoat containing waterborne and metallic effect pigments and a high solids clearcoat and co-curing all three layers at 70 to 100 ° C Also, the solids content of a two-layer film formed from primer coating agent and basecoat is comparatively high and> 75%. The core of the process disclosed in EP 1 958 982 A2 can be seen in the use of the special clearcoat material and, in particular, of the organic solvent used for its production, which makes it possible for the polyisocyanate likewise present in the clearcoat to partially migrate into the basecoat and to cure it can contribute. In the examples of EP 1 958 982 A2 described primers are each 1 K primer, which are often associated with the disadvantages already described above. In addition, when using the comparatively high solids contents described in EP 1 958 982 A2, problems with regard to sprayability and course can occur.

Finally, EP 2 087 944 A1 discloses a 3C1 B process which provides for the successive application of a water-based primer coating composition, a water-based basecoat material and a clearcoat at 40 to 110 ° C. The primer coating agent necessarily contains a polyolefin resin and an acrylic resin in a certain weight ratio to each other. The primers described in the examples of EP 2 087 944 A1 are each 1 K primers, with which the disadvantages already described above are often associated. In addition, the use of polyolefin resins in water-based primer coating agents is often disadvantageous because it negatively affects the sensitivity to water and moisture. In particular, the use of chlorinated polyolefins is disadvantageous in this regard. In addition, the use of such chlorinated polyolefins for environmental reasons is undesirable.

Moreover, primer coating compositions known from the prior art and used for coating plastics and corresponding multicoat paint systems comprising such a primer and basecoat (s) and clearcoat often do not, in particular if they have been applied to corresponding plastic substrates by means of a 3C1B process always satisfying application-technological properties such as, for example, appearance and chemical resistance.

There is therefore a need for primer coating compositions and their suitability in a multi-stage 1 B process, in particular a 3C1 B process for producing a multi-layer coating of plastic substances which do not have the aforementioned disadvantages. task

It is therefore an object of the present invention to provide an aqueous primer coating composition which can be applied to at least one surface of a plastic substrate and has advantages over the aqueous primer coating compositions known in the art. In particular, it is an object of the present invention to provide such an aqueous primer coating composition which enables a more ecological and economical coating process in the context of a 3C1 B process than conventional primer coating compositions used. At the same time, however, the required application-technological properties such as in particular appearance and chemical resistance of multicoat paint systems comprising such a primer coating, basecoat (s) and clearcoat should be optimally fulfilled and, in any case, not worsened compared with the prior art, if not improved his.

solution

This object is achieved by the claimed in the claims objects and the described in the following description of preferred embodiments of these objects.

A first aspect of the present invention is therefore a use of a primer coating composition obtainable by combining at least two mutually different and separate components (A) and (B) of a coating system, wherein component (A) is aqueous, contains at least one polymer (a1) which has functional groups reactive toward isocyanate groups and contains at least one pigment (a2) and / or at least one filler (a3), wherein component (B) is non-aqueous, contains at least one polyisocyanate (b1) having more than two free isocyanate groups and at least one organic solvent (b2), and wherein component (B) further comprises at least one Si-containing compound (b3 ) which has at least one hydrolyzable radical and at least one non-hydrolyzable organic radical for at least partial application to at least one optionally pretreated surface of a plastic substrate.

Another object of the present invention is a method for at least partially coating at least one surface of a plastic substrate with a primer, characterized in that the method comprises at least one step (1), namely

(1) at least partial application of the primer coating composition used according to the invention to at least one optionally pretreated surface of a plastic substrate.

Another object of the present invention is a method for at least partially coating at least one surface of a plastic substrate with a multi-layer coating, characterized in that the method comprises at least the following steps (1) to (7), namely

(1) at least partially applying the primer coating composition used according to the invention to at least one optionally pretreated surface of a plastic substrate,

(2) intermediate drying of the primer coating composition applied according to step (1) preferably at room temperature to obtain a primer layer,

(3) applying at least one basecoat composition to the primer layer obtained after step (2), (4) intermediate drying of the at least one basecoat composition applied according to step (3), preferably at room temperature, to obtain at least one basecoat film,

(5) applying a clearcoat composition to the at least one basecoat film obtained after step (4), and

(6) intermediate drying of the clearcoat composition applied according to step (5), preferably at room temperature to obtain a clearcoat layer, and

(7) co-curing of the thus-obtained primer layer, base coat layer (s) and clearcoat layer at a temperature <100 ° C.

A further subject of the present invention is the coating agent system used as such in connection with the abovementioned use according to the invention. Another object of the present invention is a primer coating composition obtainable by combining at least the components (A) and (B) of this coating agent system.

It has surprisingly been found that the coating agent system according to the invention is suitable for producing a primer coating composition, which in turn is suitable for at least partial application to at least one surface of a plastic substrate and in particular in the context of the inventive method as part of a multi-layer coating on an optionally pretreated Plastic substrate can be applied. This is advantageous for both ecological reasons, since a primer coating composition prepared from the coating system according to the invention is an aqueous composition, as well as for economic reasons, because of the suitability of the primer coating composition, to be used in a 3C1 B process , economic benefits result because time and costs (energy input) can be reduced: in particular, if the inventive method is used as part of a series coating of plastic parts or a coating of plastic parts within an OEM OEM painting of car bodies or parts thereof, due to the common curing step of all applied layers only a single oven can be used to cure all layers.

Furthermore, it has surprisingly been found that the required application-technological properties of both the resulting primer coatings and of multicoat paint systems comprising primer coating, basecoat (s) and clearcoat are optimally fulfilled and, in particular, no disadvantages, but even advantages, can be observed with regard to these properties in terms of appearance, hue, stone chip resistance and chemical resistance. It was surprising that this is achieved in particular by the presence of the at least one Si-containing compound (b3).

Detailed description

The term "comprising" in the sense of the present invention, in particular in connection with the coating agent system according to the invention and the coating composition obtainable therefrom preferably has the meaning "consisting of". In this case, for example, with regard to the components (A) and (B) of the coating agent system used according to the invention - in addition to the components contained therein compulsory (polymer (a1), water, pigment (a2) and / or filler (a3) in the case of (A) and Polyisocyanate (b1), organic solvent (b2) and Si-containing compound (b3) in the case of (B)) - one or more of the other optional constituents mentioned below may be contained in these components. All components can be present in each case in their preferred embodiments mentioned below. The same applies to the coating compositions of the invention obtainable from the coating system according to the invention.

substratum

Suitable substrates used according to the invention are all plastic substrates conventionally used and known to the person skilled in the art. at For the purposes of the present invention, "plastic substrates" or "substrates made of plastic" (also referred to below as "substrates according to the invention") are preferably substrates made of or based on at least one plastic. In particular, such substrates are plastic substrates which have at least one surface made of plastic. Suitable plastics are all customary plastics known to the person skilled in the art, in particular polystyrene (PS), polyvinyl chloride (PVC), polyurethane (PUR) or (PUR-RIM), glass-fiber-reinforced unsaturated polyesters, polymethyl methacrylate (PMMA), polyphenylene sulfide (PPS), polyoxymethylene (POM), polyphenylene ether (PPE), polyphenylene oxide (PPO), polyurea, polybutadiene terephthalate (PBT), polycarbonate (PC), polycarbonate (PC) modified with polybutadiene terephthalate (PC-PBT), acrylonitrile-butadiene-styrene copolymers (ABS), Polyolefins such as polyethylenes (PE) and polypropylene (PP) and polyolefins such as polypropylene (PP), which are modified with ethylene-propylene-diene copolymers (EPDM) and / or with ethylene-butylene-diene copolymers (EBDM). Also possible are Kunststoffsu bstrate containing various of these plastics, therefore, mixtures of these plastics. Particularly preferred plastics are polyolefins such as polypropylene (PP) and polypropylene (PP), which are optionally modified with ethylene-propylene-diene copolymers (EPDM). The modification of polyolefins with EPDM essentially serves to elastify the plastic and may inter alia influence the paintability of the plastic. EPDM contents of at least 2% by weight, for example from 2 to 20% by weight, based on the total weight of the plastic, are advantageous.

The substrate used according to the invention may be pretreated or untreated, but is preferably a pretreated substrate. Possible pretreatments to which the substrate can be subjected are flaming, plasma treatment and / or corona discharge, in particular flaming. These pretreatments are known to the person skilled in the art.

The substrates used according to the invention may be plastic plates. Vehicle substrates and vehicle attachment parts and vehicle accessories made of plastics are preferably used as substrates for both the vehicle interior area and the vehicle exterior area. Inventive coating agent system

The coating agent system according to the invention is suitable for the preparation of a primer coating composition.

The skilled person is familiar with the term "primer" or the "primer coating composition". For the purposes of the present invention and in accordance with DIN EN ISO 4618 (German version, date: March 2007), it is understood to mean a base coating composition which is used to produce a base coating on the substrate to be coated. The resulting base coat then represents the first layer of a multi-layer finish on the substrate.

The coating agent system according to the invention comprises at least the components (A) and (B). Preferably, it may consist of the two components (A) and (B). In this case, the coating agent system according to the invention is a two-component coating agent system (2K coating agent system). Alternatively, the coating system according to the invention may comprise, in addition to the two components (A) and (B), another component (C) different from (A) and (B) and likewise separate from (A) and (B). This component (C) acts as a dilution component containing one or more organic solvents and / or water.

By combining at least the components (A) and (B) and optionally (C) of the coating system according to the invention, preferably shortly before the intended application to the substrate, a primer coating composition according to the invention is obtainable.

The primer coating composition according to the invention, which can be prepared by combining at least the two components (A) and (B) and, if appropriate, (C), is also completely aqueous due to the use of the aqueous component (A). The components (A) and (B) within the coating system according to the invention are preferably present relative to one another such that the molar ratio of the isocyanate-reactive functional groups of the polymer (a1), which are preferably OH groups, and the isocyanate groups of the polyisocyanate (b1) in a range from 1: 1 to 1:20, particularly preferably in a range from 1: 1, 1 to 1:15, very particularly preferably in a range from 1: 1, 2 to 1:12, 5, more preferably in a range of 1: 1, 5 to 1: 10, most preferably in a range of 1: 2 to 1: 9, is located.

The components (A) and (B) within the coating system according to the invention are preferably present relative to one another such that the NCO content of a coating composition obtainable by combining at least the two components (A) and (B) and optionally (C) is in each case based on the total solids of this composition, in a range of 1 to 12 wt .-%, particularly preferably in a range of 1 to 10 wt .-%, most preferably in a range of 1, 5 to 9 wt. %, more preferably in a range of 2 to 8 wt%, most preferably in a range of 3 to 7 wt%. The NCO content corresponds in each case to the theoretically calculated NCO content.

Component (A)

The proportions in% by weight of all constituents contained in the component (A) used according to the invention add up to 100% by weight, based on the total weight of component (A).

Component (A) of the coating agent system according to the invention is aqueous. For the purposes of the present invention, the term "aqueous" in connection with component (A) is to be understood as meaning a system which comprises, as solvent, as the main constituent water, preferably in an amount of at least 25% by weight, and organic solvents in minor proportions, preferably in an amount of <20 wt .-%, in each case based on the total weight of component (A).

polyhydric alcohols, for example methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, ethylene glycol, ethyl glycol, propyl glycol, butyl glycol, butyldiglycol, 1,2-propanediol and / or 1,3-propanediol, ethers, for example diethylene glycol dimethyl ether, aliphatic Hydrocarbons, aromatic hydrocarbons, for example toluene and / or xylenes, ketones, for example acetone, N-methylpyrrolidone, N-ethylpyrrolidone, methyl isobutyl ketone, isophorone, cyclohexanone, methyl ethyl ketone, esters, for example optionally included in the definition of a binder and optionally present additives.

Preferably, the at least one polymer (a1) used within component (A) is selected from the group consisting of polyurethanes, polyureas, polyesters, polyamides, polyethers, poly (meth) acrylates and / or copolymers of said polymers, in particular polyurethane-poly ( meth) acrylates and / or polyurethane-polyureas. More preferably, the at least one polymer used in component (A) is selected from the group consisting of polyurethanes, polyesters, poly (meth) acrylates and / or copolymers of said polymers. The term "(meth) acrylic" or "(meth) acrylate" in the context of the present invention in each case the meanings "methacrylic" and / or "acrylic" or "methacrylate" and / or "acrylate".

Preferred polyurethanes are described, for example, in German patent application DE 199 48 004 A1, page 4, line 19 to page 11, line 29 (polyurethane prepolymer B1), in European patent application EP 0 228 003 A1, page 3, line 24 to page 5, Line 40, European Patent Application EP 0 634 431 A1, page 3, line 38 to page 8, line 9, and international patent application WO 92/15405, page 2, line 35 to page 10, line 32.

Preferred polyesters are described, for example, in DE 4009858 A1 in column 6, line 53 to column 7, line 61 and column 10, line 24 to column 13, line 3 or WO 2014/033135 A2, page 2, line 24 to page 7, line 10 and page 28, line 13 to page 29, line 13 described.

Preferred polyurethane-poly (meth) acrylate copolymers ((meth) acrylated polyurethanes) and their preparation are described, for example, in WO 91/15528 A1, page 3, line 21 to page 20, line 33 and in DE 4437535 A1, page 2, line 27 to page 6, line 22 described.

Preferred poly (meth) acrylates are also those which can be prepared by multistage free-radical emulsion polymerization of olefinically unsaturated monomers in water and / or organic solvents. Especially For example, seed-core-shell polymers (SCS polymers) are preferred. Such polymers or aqueous dispersions containing such polymers are known, for example, from WO 2016/116299 A1.

Preferred polyurethane-polyurea copolymers are polyurethane-polyurea particles, wherein the polyurethane-polyurea particles, in each case in reacted form, at least one isocyanate group-containing polyurethane prepolymer containing anionic and / or anionic groups convertible groups and at least one polyamine containing two contain primary amino groups and one or two secondary amino groups. Preferably, such copolymers are used in the form of an aqueous dispersion. Such polymers can in principle be prepared by conventional polyaddition of, for example, polyisocyanates with polyols and polyamines.

Preferably, no polyolefins are used as polymer (a1). Preferably, none of components (A), (B) and optionally (C) of the coating system contains any polyolefins. Accordingly, the coating composition according to the invention preferably also contains no polyolefins.

The polymer (a1) used in component (A) has reactive functional groups enabling a crosslinking reaction with isocyanate groups. Any conventional crosslinkable reactive functional group which can be used for this purpose and which is known to the person skilled in the art is considered here. The polymer (a1) used in component (A) preferably has at least one type of functional reactive group selected from the group consisting of primary amino groups, secondary amino groups, hydroxyl groups, thiol groups, carboxyl groups and carbamate groups. Groups on. Preferably, the polymer (a1) used in component (A) has functional hydroxyl groups.

Preferably, the polymer (a1) used in component (A) is hydroxy-functional and particularly preferably has an OH number in the range from 15 to 250 mg KOH / g, more preferably from 20 to 200 mg KOH / g. The OH number can be calculated. The polymer (a1) used in component (A) is particularly preferably a hydroxy-functional polyurethane-poly (meth) acrylate copolymer, a hydroxy-functional polyester and / or a hydroxy-functional polyurethane-polyurea copolymer.

Component (AI) contains at least one pigment (a2) and / or at least one filler (a3).

The term "pigment" is known to the person skilled in the art, for example from DIN 55943 (date: October 2001). For the purposes of the present invention, a "pigment" is preferably understood to mean pulverulent or platelet-like constituents which are present in the surrounding application medium, for example component (A) of the coating agent system according to the invention or of the coating composition according to the invention are substantially, preferably completely, insoluble. These are preferably colorants and / or substances that can be used as a pigment because of their magnetic, electrical and / or electromagnetic properties. Of "fillers" pigments are preferably distinguished by their refractive index, which is> 1, 7 for pigments.

The term "pigments" encompasses color pigments (the terms "coloring pigment" and "color pigments" are interchangeable) and effect pigments Preferably, the effect pigments are pigments which have an optically effecting or color and optically effecting, in particular optically effecting effect "Optically effecting and coloring pigment", "optically effecting pigment" and "effect pigment" are therefore interchangeable. Preferred effect pigments are, for example, platelet-shaped metallic effect pigments such as platelet-shaped aluminum pigments, gold bronzes, fire-colored bronzes and / or iron oxide-aluminum pigments, perglaze pigments such as fish-silver, basic lead carbonate, bismuth oxychloride and / or metal oxide-mica pigments (mica) and / or other effect pigments such as platelet-shaped graphite, platelet-shaped Iron oxide, multi-layer effect pigments from PVD films and / or liquid crystal polymer pigments. In principle, the use of effect pigments as pigment (a2) in component (A) is possible. However, since the coating agent composition obtainable using (A) is to be used as a primer coating composition, the incorporation of effect pigments into component (A) is not preferred. Preferably, component (A) thus contains no effect pigments. The entire coating system according to the invention and also the coating composition obtainable therefrom preferably contain no effect pigments.

As pigment (a2), therefore, color pigments are preferably used. As a color pigment inorganic and / or organic pigments can be used. Preferably, the color pigment is an inorganic color pigment. Particularly preferred color pigments used are white pigments, colored pigments and / or black pigments. Examples of white pigments are titanium dioxide, zinc white, zinc sulfide and lithopone. Examples of black pigments are carbon black, iron manganese black and spinel black. Examples of colored pigments are chromium oxide, chromium oxide hydrate green, cobalt green, ultramarine green, cobalt blue, ultramarine blue, manganese blue, ultramarine violet, cobalt and manganese violet, iron oxide red, cadmium sulfoselenide, molybdate red and ultramarine red, iron oxide brown, mixed brown, spinel and corundum phases and chromium orange, iron oxide yellow, nickel titanium yellow, chrome titanium yellow, Cadmium sulfide, cadmium zinc sulfide, chrome yellow and bismuth vanadate. Examples of suitable organic coloring pigments are monoazo pigments, bisazo pigments, anthraquinone pigments, benzimidazole pigments,

Quinacridone pigments, quinophthalone pigments, diketopyrrolopyrrole pigments, dioxazine pigments, indanthrone pigments, isoindoline pigments, isoindolinone pigments, azomethine pigments, thioindigo pigments, metal complex pigments, perinone pigments, perylene pigments, phthalocyanine pigments or aniline black.

The proportion of the pigments (a2) is preferably in the range from 1, 0 to 40.0 wt .-%, preferably 2.0 to 35.0 wt .-%, particularly preferably 5.0 to 30.0 wt .-% , in each case based on the total weight of component (A). The proportion of the pigments (a2) is preferably in the range of 0.5 to 35.0 wt%, preferably 1.0 to 30.0 wt%, particularly preferably 2.0 to 25 wt%, respectively based on the total weight of the coating composition according to the invention obtainable from the coating system according to the invention.

The term "filler" is also known to the person skilled in the art, for example from DIN 55943 (date: October 2001). For the purposes of the present invention, a "filler" is understood to mean essentially, preferably completely, insoluble constituent in the application medium such as, for example, component (A) of the coating agent system or of the coating composition according to the invention, which is preferably used to increase the volume "Fillers" in the context of the present invention of "pigments" by their refractive index, which is <1.7 for fillers.

Any customary filler known to those skilled in the art can be used as constituent (a3). Examples of suitable fillers are kaolin, dolomite, calcite, chalk, calcium sulfate, barium sulfate, graphite, silicates such as magnesium silicates, in particular corresponding phyllosilicates such as hectorite, bentonite, montmorillonite, talc and / or mica, silicic acids, in particular fumed silicas, hydroxides such as aluminum hydroxide or magnesium hydroxide or organic fillers such as textile fibers, cellulose fibers, polyethylene fibers or polymer powder; in addition, reference is made to Rompp Lexikon Lacke und Druckfarben, Georg Thieme Verlag, 1998, pages 250 ff., "Fillers".

The proportion of fillers (a3) is preferably in the range from 1.0 to 40.0% by weight, preferably 2.0 to 35.0% by weight, particularly preferably 5.0 to 30.0% by weight. , in each case based on the total weight of component (A).

The proportion of the fillers (a3) is preferably in the range of 0.5 to 35.0 wt .-%, preferably 1, 0 to 30.0 wt .-%, particularly preferably 2.0 to 25 wt .-%, respectively based on the total weight of the inventive Coating agent available coating composition according to the invention.

Component (A) may optionally contain at least one thickener (also referred to as thickener). Examples of such thickeners are inorganic thickeners, for example metal silicates such as sheet silicates, and organic thickeners, for example poly (meth) acrylic acid thickeners and / or (meth) acrylic acid (meth) acrylate copolymer thickeners, polyurethane thickeners and polymeric waxes. The metal silicate is preferably selected from the group of smectites. The smectites are particularly preferably selected from the group of montmorillonites and hectorites. In particular, the montmorillonites and hectorites are selected from the group consisting of aluminum-magnesium silicates and sodium-magnesium and sodium-magnesium fluorine-lithium phyllosilicates. These inorganic phyllosilicates are marketed, for example, under the trademark Laponite®. Thickeners based on poly (meth) acrylic acid and (meth) acrylic acid (meth) acrylate copolymer thickeners are optionally crosslinked and / or neutralized with a suitable base. Examples of such thickeners are "Alkali Swellable Emulsions" (ASE), and hydrophobically modified variants thereof, the "Hydrophically Modified Alkali Swellable Emulsions" (HASE). Preferably, these thickeners are anionic. Corresponding products such as Rheovis® AS 1 130 are commercially available. Polyurethane based thickeners (e.g., polyurethane associative thickeners) are optionally crosslinked and / or neutralized with a suitable base. Corresponding products such as Rheovis® PU 1250 are commercially available. Examples of suitable polymeric waxes are optionally modified polymeric waxes based on ethylene-vinyl acetate copolymers. A corresponding product is commercially available, for example, under the name Aquatix® 8421.

The at least one thickener in component (A) is preferably present in an amount of at most 10% by weight, particularly preferably at most 7.5% by weight, very particularly preferably at most 5% by weight, in particular not more than 3% by weight .-%, most preferably of at most 2 wt .-%, each based on the total weight of component (A) before. The minimum amount of thickener is here preferably in each case at 0.1 wt .-%, based on the total weight of component (A).

Component (A) may contain one or more commonly used additives as further optional ingredients. For example, the component (A) as already mentioned above may contain a certain amount of at least one organic solvent. Furthermore, component (A) can at least one additive selected from the group consisting of reactive diluents, light stabilizers, antioxidants, deaerators, emulsifiers, slip additives, polymerization inhibitors, initiators for free-radical polymerizations, adhesion promoters, flow control agents, film-forming aids, Sag control agents (SCAs ), Flame retardants, corrosion inhibitors, siccatives, biocides and matting agents. They can be used in the known and customary proportions. Preferably, their content, based on the total weight of component (A) is from 0.01 to 20.0 wt .-%, more preferably from 0.05 to 15.0 wt .-%, particularly preferably from 0.1 to 10 , 0 wt .-%, most preferably at 0.1 to 7.5 wt .-%, in particular at 0.1 to 5.0 wt .-% and most preferably at 0.1 to 2.5 wt. -%.

Component (B)

The proportions in% by weight of all constituents contained in the component (B) used according to the invention add up to 100% by weight, based on the total weight of component (B).

Component (B) of the coating agent system according to the invention is non-aqueous. For the purposes of the present invention, the term "nonaqueous" in connection with component (B) is to be understood as meaning a system which is at least essentially anhydrous The presence of water within component (B) is undesirable because it would otherwise be too In addition, there may be a reaction of water with the Si-containing compound (b3) such as a silane with elimination of an alcohol, which in turn with an NCO group The polyisocyanate (b1) may also react in this case as well formed silanol group react with another such group and / or with a hydrolyzable group of the Si-containing compound (b3), which is also undesirable at this time. However, the presence of traces of water - for example, by the presence of water in components used to prepare component (B) - can not be completely ruled out. Therefore, component (B) is at least substantially anhydrous. This is preferably understood to mean that component (B) contains water in an amount of at most 0.5% by weight, particularly preferably at most 0.25% by weight, very particularly preferably at most 0.1% by weight, in particular of <0.1 wt .-%, most preferably of <0.05 wt .-% or no water, in each case based on the total weight of component (B).

Component (B) contains at least one organic solvent (b2), preferably in an amount of up to 40% by weight, based on the total weight of component (B). Suitable organic solvents (b2) are the same solvents which have already been mentioned above in connection with component (A). However, in order to prevent (premature) crosslinking with the isocyanate groups of the polyisocyanate (b1), (b2) is preferably chemically inert to a reaction with the isocyanate groups of (b1). In particular, (b2) is therefore not an alcohol.

The component (B) used according to the invention preferably contains a proportion of (b2) of up to 37.5% by weight, more preferably of up to 35% by weight, very particularly preferably of up to 32.5% by weight. , in particular of up to 30 wt .-%, each based on the total weight of component (B).

The component (B) used according to the invention preferably contains a proportion of (b2) which is in a range from 1 to 40% by weight, more preferably in a range from 2 to 37.5% by weight, very particularly preferably in one Range from 3 to 35 wt .-%, in particular from 4 wt .-% to 32.5 wt .-% or from 5 wt .-% to 30 wt .-%, in each case based on the total weight of component (B) ,

Preferably, the solids content of the component (B) used according to the invention is in a range from 50 to 99% by weight, more preferably in a range of 55 to 95 wt .-%, most preferably in a range of 60 to 90 wt .-%, in particular from 65 wt .-% to 85 wt .-%, in each case based on the total weight of component (B ). The solids content is determined by the method described below.

Component (B) of the coating agent system according to the invention comprises at least one polyisocyanate (b1) having more than two free isocyanate groups.

Preferred polyisocyanates (b1) are (hetero) aliphatic, (hetero) cycloaliphatic, (hetero) aromatic and / or (hetero) aliphatic (hetero) aromatic polyisocyanates.

The at least one polyisocyanate (b1) preferably has on average 2.4 to 4, preferably 2.6 to 4 and particularly preferably 2.8 to 3.6 NCO groups and preferably contains at least one isocyanurate ring and / or iminooxadiazinedione Ring. Preferably, the isocyanurate ring and the iminooxadiazinedione ring are each formed by trimerization of diisocyanates, which are preferably selected from the group consisting of hexamethylene diisocyanate and isophorone diisocyanate and mixtures thereof.

Particular preference is given to using isocyanurate trimers of hexamethylene diisocyanate and / or isophorone diisocyanate and / or oligomers and / or polymers of isophorone diisocyanate and / or hexamethylene diisocyanate as polyisocyanate (b1) within component (B). The person skilled in the art is familiar with corresponding commercially available products. Examples are products from the Desmodur® series from Bayer such as Desmodur® XP 2565 and / or Desmodur® N 3600. Very particularly preferably, isocyanurate trimers of hexamethylene diisocyanate are used as polyisocyanate (b1) within component (B).

The component (B) used according to the invention preferably contains a proportion of (b1) which is in a range from 50 to 95% by weight, more preferably in a range from 55 to 92.5% by weight, very particularly preferably in a range of 60 to 90% by weight, especially 62.5% to 87.5% by weight or 60% The Si-containing compound (b3) has at least one hydrolyzable preferably organic radical, ie one or more, for example two or three, of such radicals.

The Si-containing compound (b3) also has at least one, i. one or more, for example two or three, non-hydrolyzable organic radical. This, in turn, may optionally have at least one isocyanate-reactive functional group which in turn is optionally masked with at least one protective group cleavable under hydrolytic conditions.

Isocyanate-reactive functional groups of the non-hydrolyzable organic radical of the at least one Si-containing compound (b3), which are optionally masked with at least one protective group cleavable under hydrolytic conditions, are preferably selected from the group consisting of hydroxyl groups, Thiol groups, primary and secondary amino groups and mixtures thereof.

The at least one isocyanate-reactive functional group of the non-hydrolyzable organic radical of the at least one Si-containing compound (b3) can - as long as (b3) is present in component (B), - masked with a protective group cleavable under hydrolytic conditions be to prevent an immediate reaction with the isocyanate groups of the polyisocyanate (b1), which is also present in the component (B).

Preferably, the non-hydrolyzable organic radical of the at least one Si containing compound (b3) is selected from the group consisting of aliphatic radicals of 1 to 24 carbon atoms, cycloaliphatic radicals of 3 to 12 carbon atoms, aromatic radicals of 6 to 12 carbon atoms and araliphatic Rests having 7 to 18 carbon atoms, each of these radicals optionally having at least one isocyanate-reactive functional group, which group is in turn optionally masked with at least one cleavable under hydrolytic conditions protecting group. In addition, any of the aforementioned aliphatic, cycloaliphatic, aromatic and araliphatic radicals contain one or more heteroatoms such as N, O and / or S and / or heteroatom groups. For example, each of these radicals, in particular a corresponding aliphatic radical, may contain at least one epoxide group.

Examples of Si-containing compounds (b3) having at least one non-hydrolyzable organic group selected from the group consisting of aliphatic groups having 1 to 24 carbon atoms are Si-containing compound (b3) having at least one aliphatic group of 1 are methyltrimethoxysilane (MTMS), methyltriethoxysilane (MTES), methyltripropoxysilane, methyltriisopropoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane,

Ethyltripropoxysilane, ethyltriisopropoxysilane, octyltrimethoxysilane,

Isobutyltriethoxysilane, 1-butyltrimethoxysilane, octyltriethoxysilane,

Hexyltrimethoxysilane, hexyltriethoxysilane, decyltrimethoxysilane, and decyltriethoxysilane, hexadecyltrimethoxysilane, hexadecyltriethoxysilane and 1, 2-bis (triethoxysilyl) ethane and 1, 2-bis (trimethoxysilyl) ethane.

Examples of Si-containing compounds (b3) having at least one non-hydrolyzable organic radical selected from the group consisting of aromatic radicals having 6 to 12 carbon atoms are phenyltrimethoxysilane (PHS), phenyltriethoxysilane, phenyltripropoxysilane and phenyltriisopropoxysilane.

Examples of Si-containing compounds (b3) having at least one non-hydrolyzable organic radical selected from the group consisting of araliphatic radicals having 7 to 18 carbon atoms are benzyltrimethoxysilane, benzyltriethoxysilane, benzyltripropoxysilane and benzyltriisopropoxysilane.

The Si-containing compound (b3) may contain at least one Si-containing radical such as exactly one such radical (as in the case of monosilanes) or even several such radicals (as in the case of bis- or tris-silanes) as in the case of 1, 2-bis (triethoxysilyl) ethane. It is also possible to use Si-containing compounds (b3) which have four, five, six or more silyl groups. Examples of such silane-containing compounds (b3) are, for example, reaction products of bis-silanes whose silyl groups are bridged via an alkyl radical which has a secondary amino group. Group carries (such as the commercial product Dynasylan® 1124) with such polyisocyanates, which can be used for example as a polyisocyanate (b1), such as isocyanurate trimers (especially HDI trimers). Such reaction products have a total of six silyl groups.

Hydrolyzable silane compounds containing at least one primary and / or secondary amino group are, for example, 3-aminopropyltrimethoxysilane (APS), 3-aminopropyltriethoxysilane, 3-aminopropyltriisopropoxysilane, 2-aminoethyltrimethoxysilane, 2-aminoethyltriethoxysilane, 2 -Aminoethyltriisopropoxysilane, aminomethyltrimethoxysilane, aminomethyltriethoxysilane, aminomethyltriisopropoxysilane, 3- (2-aminoethyl) aminopropyltrimethoxysilane (AEAPS), 3- (2-aminoethyl) aminopropyltriethoxysilane, 3- (2-aminoethyl) aminopropyltriisopropoxysilane, 2- (2- Aminoethyl) aminoethyltrimethoxysilane, 2- (2-aminoethyl) aminoethyltriethoxysilane 2- (2-aminoethyl) aminoethyltriisopropoxysilane, 3- (3-aminopropyl) aminopropyltrimethoxysilane, 3- (3-aminopropyl) aminopropyltriethoxysilane, 3- (3-aminopropyl ) aminopropyltriisopropoxysilane, diethylenetriaminopropyltrimethoxysilane, diethylenetriaminopropyltriethoxysilane, N- (n-butyl) -3-aminopropyltrimethoxysilane, N- (n-butyl) -3-aminopropyltriethoxysilane, N-cyclo hexylaminomethyltriethoxysilane, N-cyclohexylaminomethyltrimethoxysilane, N-ethyl-Y-aminoisobutyltrimethoxysilane, N-ethyl-y-aminoisobutyltriethoxysilane, N- (vinylbenzyl) -2-aminoethyl-3-aminopropyltrimethoxysilane hydrochloride, N-phenyl-Y-aminopropyltrimethoxysilane, N- Phenyl-γ-aminopropyltriethoxysilane, γ-ureidopropyltrimethoxysilane, γ-

Ureidopropyltriethoxysilane, N-methyl- [3- (trimethoxysilyl) propyl] carbamate, and / or N-trimethoxysilylmethyl-O-methylcarbamate and bis [Y- (triethoxysilyl) propyl] amine, bis [Y- (trimethoxysilyl) propyl amine]. Bis [Y- (triethoxysilyl) propyl] amine, and bis [y- (trimethoxysilyl) propyl] amine. Each of these silane compounds can be used as the Si-containing compound (b3). In addition, the amino group of each of these compounds may be masked with a protective group cleavable under hydrolytic conditions. Corresponding protective groups with which the amino function can be protected are known to the person skilled in the art. For example, dimethylbutylidene groups which can be cleaved off under hydrolysis according to the following scheme are suitable for this purpose:

Optional component (C)

In addition to the two components (A) and (B), the coating agent system according to the invention may comprise a further component (C) different from (A) and (B) and likewise separate from (A) and (B). This component (C) acts as a dilution component containing one or more organic solvents and / or water. Component (C) thus contains at least one organic solvent and / or water. Suitable organic solvents are the same solvents which have already been mentioned above in connection with components (A) and (B).

Inventive coating composition

A further subject of the present invention is a primer coating composition obtainable by combining at least the components (A) and (B) of the coating agent system according to the invention. The term "combination" includes mixing, especially homogeneous mixing.

All the preferred embodiments described hereinbefore in connection with the coating agent system according to the invention are also preferred embodiments with regard to the coating composition according to the invention.

The proportions in% by weight of all constituents contained in the coating composition according to the invention add up to 100% by weight, based on the total weight of the coating composition.

The coating composition of the invention is aqueous overall. For the purposes of the present invention, the term "aqueous" in connection with the coating composition according to the invention is to be understood as meaning a system which comprises, as solvent, as the main constituent water, preferably in an amount of at least 17.5% by weight, and organic solvents in minor proportions , preferably in an amount of <15% by weight, contains, in each case based on the total weight of the coating composition according to the invention.

The coating composition according to the invention preferably contains a proportion of water of at least 20% by weight, more preferably of at least 22.5% by weight, most preferably of at least 25% by weight, based in each case on the total weight of the coating composition according to the invention.

The coating composition according to the invention preferably contains a proportion of water which is in a range from 17.5 to 65% by weight, more preferably in a range from 20 to 60% by weight, very particularly preferably in a range from 25 to 55% by weight .-%, in each case based on the total weight of the coating composition according to the invention.

Preferably, the coating composition of the invention contains a proportion of organic solvents in a range of <15 wt .-%, more preferably in a range of 2 to <15 wt .-%, most preferably in a range of 3 to 14 wt. % or up to 13% by weight or up to 10% by weight, in each case based on the total weight of the coating composition according to the invention.

The solids content of the coating composition according to the invention is preferably in a range from 10 to 70% by weight, more preferably in a range from 15 to 65% by weight, very particularly preferably in a range from 20 to 60% by weight, in particular from 25% by weight to 55% by weight, in each case based on the total weight of the coating composition according to the invention. The solids content is determined by the method described below.

Preferably, the molar ratio of the isocyanate group-reactive functional groups of the polymer (a1), which are preferably OH groups, and the isocyanate groups of the polyisocyanate (b1) in the coating composition to each other is in a range of 1: 1 to 1: 20 particularly preferably in a range from 1: 1, 1 to 1:15, very particularly preferably in a range from 1: 1, 2 to 1: 12.5, particularly preferably in a range from 1: 1.5 to 1:10 , most preferably in a range of 1: 2 to 1: 9, before.

Preferably, the NCO content of the coating composition according to the invention, in each case based on the total solids, in a range of 1 to 12 wt .-%, more preferably in a range of 1 to 10 wt .-%, most preferably in one Range of 1, 5 to 9 wt .-%, more preferably in a range of 2 to 8 wt .-%, most preferably in a range of 3 to 7 wt .-% - The NCO content corresponds in each case to the theoretical calculated NCO content.

Use according to the invention

A further subject matter of the present invention is a use of the coating system according to the invention or the coating composition according to the invention for the at least partial application of a primer coating composition to at least one optionally pretreated surface of a plastic substrate.

All the preferred embodiments described above in connection with the coating agent system according to the invention and the coating agent composition according to the invention herein are also preferred embodiments with regard to the abovementioned use according to the invention.

Inventive method

Another object of the present invention is a method for at least partially coating at least one surface of a plastic substrate with a primer, characterized in that the method comprises at least one step (1), namely (1) at least partially applying the primer coating composition of the invention to at least one optionally pretreated surface of a plastic substrate.

All the preferred embodiments described hereinbefore in connection with the coating agent system according to the invention and the coating composition according to the invention are also preferred embodiments with regard to the abovementioned method according to the invention.

(1) at least partially applying the primer coating composition of the invention to at least one optionally pretreated surface of a plastic substrate,

(3) applying at least one basecoat composition to the primer layer obtained after step (2),

(4) intermediate drying of the at least one basecoat composition applied according to step (3), preferably at room temperature, to obtain at least one basecoat film,

(7) co-curing of the thus-obtained primer layer, base coat layer (s) and clearcoat layer at a temperature <100 ° C. All the preferred embodiments described hereinbefore in connection with the coating agent system according to the invention and the coating composition according to the invention are also preferred embodiments with regard to the abovementioned method according to the invention.

The method according to the invention for at least partially coating at least one surface of a plastic substrate with a multi-layer coating is a wet-on-wet method in which the primer layer, basecoat layer and clearcoat layer are applied wet in steps (1), (3) and (5) and only after that all three layers are hardened together. If a basecoat film is applied within step (3), the process is a 3C1B process. If two basecoat films are applied within step (3), the process is a 4C1B process. However, a 3C1 B method is preferred. The process according to the invention is preferably used in automotive OEM finishing.

The term "basecoat" or "basecoat film" is known to the person skilled in the art and preferably serves as a name for a paint coating and / or effect intermediate coating in general industrial coating, in particular automotive (series) painting. The basecoat or the basecoat film preferably forms the second layer of a three-coat finish of primer, basecoat and clearcoat. Commercially available basecoats can be used as basecoats, with aqueous basecoats being preferred. When two-component basecoats are used, the same binder components described above as components (a1) and (b1) can be used. If 1 K basecoats are used, which is preferred, then the same binder components can be used, which have been described above as components (a1). As crosslinkers of the binder system in this case, for example, aminoplast resins such as melamine resins and in particular melamine-Formaldeydharze, and / or blocked polyisocyanates can be used. But it is also possible and preferred that the binder components used are not chemically crosslinking and the basecoat is therefore not cured by chemical curing, but only by physical drying. As is known, a clearcoat is a coating composition which, after application and curing, forms a transparent coating (the cured clearcoat film) with protective and / or decorative properties. Protective properties are, for example, scratch resistance and weather resistance, in particular UV resistance. As a decorative property, for example, to understand a good gloss. The clearcoats to be used are the clearcoats commonly used in the field of plastic coating, the selection and use of which is known to the person skilled in the art (cf. also Rompp-Lexikon Lacke und Druckfarben, Georg Thieme Verlag, Stuttgart, New York, 1998, page 325) ). As clearcoats, it is thus possible to use commercial clearcoats which are solvent-based. 2K clearcoats are preferred. It is possible to use the component (B) used according to the invention also as a hardener component of such a 2K clearcoat.

Step 1)

In step (1), a plastic substrate is used which has at least one optionally pretreated surface. The pretreatment is carried out optionally and preferably before carrying out step (1). Possible pretreatments to which the substrate can be subjected are flaming, plasma treatment and / or corona discharge, in particular flaming.

The application of the primer coating composition according to the invention in step (1) takes place in such a way that the resulting primer layer after carrying out step (6) is most preferably a dry film thickness in the range from 5 to 150 .mu.m, more preferably from 8 to 120 .mu.m from 10 to 100 pm, in particular from 10 to 80 pm.

Steps (2)

Step (2) provides intermediate drying of the primer coating composition applied according to step (1) to obtain a primer layer. Step 3)

The application of the basecoat composition in step (3) takes place in such a way that the resulting basecoat film after carrying out step (6) preferably has a dry film thickness in the range from 5 to 80 μm, particularly preferably from 7.5 to 70 μm, in particular from 10 to 60 μm , Most preferably from 10 to 50 μιτι has.

Step (4)

Step (4) provides intermediate drying of the basecoat composition applied according to step (3) to obtain a basecoat film.

Step (5)

The application of the clearcoat composition in step (5) takes place in such a way that the resulting clearcoat film after carrying out step (6) preferably has a dry film thickness in the range from 20 to 60 μm, particularly preferably from 25 to 50 μm.

Step (6)

Step (6) provides intermediate drying of the clearcoat composition applied according to step (5) to obtain a clearcoat layer.

Step (7)

Step (7) provides for co-curing of the primer layer, basecoat layer (s) and clearcoat layer thus obtained at a temperature <100 ° C.

The application of the aqueous primer / coating composition according to the invention in step (1) and, analogously, the applications according to steps (3) and (5) can be carried out by all customary application methods, such as, for example, spraying, knife coating, brushing, pouring, dipping, impregnating, Trickling or rolling, preferably by spray application. In this case, the substrate to be coated can rest as such, with the application device or application system being moved. However, the substrate to be coated can also be moved, with the application system resting relative to the substrate or being moved in a suitable manner. Preferably, spray application methods applied, such as compressed air spraying (pneumatic application), airless spraying, high rotation, electrostatic spray application (ESTA), optionally combined with hot spray application such as hot air hot spraying. ESTA is particularly preferred.

The intermediate drying steps (2), (4) and (6) provide for partial drying of the respective coating composition applied. For the purposes of the present invention, the term "drying" is to be understood as meaning the partial removal of organic solvent and / or water from the paint applied in each case Depending on the nature of the binder used, crosslinking reactions may of course already occur in each case, however, it is not yet complete, ie, no hardened lacquer layer is formed.The intermediate drying is in each case preferably at room temperature, ie at a temperature in the range from 10 to 50 ° C., preferably from 12 to 45 ° C., particularly preferred at a temperature in the range of 14 to 40 ° C, more preferably at a temperature of 16 to 35 ° C, most preferably at a temperature of 18 to 25 ° C, in each case for preferably 5 to 30, more preferably 7 to 25 minutes, more preferably 10 to 20 minutes.

The intermediate drying steps (2) and (4) and (6) are preferably carried out by air supply, wherein the air velocity of the supplied air is preferably at least 0.3 m / s, more preferably at least 0.4 m / s, most preferably in a range of 0.4 to 0.8 m / s or even higher.

The joint curing according to step (7) of the method according to the invention has no special features, but is carried out by the usual and known methods such as heating in a convection oven and / or by irradiation with IR lamps. Also possible is the actinic curing by, for example, UV radiation in radiation-curing systems. The curing conditions, in particular the curing temperatures, depend, for example, on the temperature sensitivity of the substrates used or on the choice of the binders used. In the present case, the curing takes place at a temperature <100 ° C, more preferably at 60 ° C to <100 ° C, very particularly preferably at 70 ° C to 95 ° C. Also, the duration of the curing phase is chosen individually and is inter alia dependent on the factors already mentioned (for example, choice of the binder and / or the curing temperatures). For example, the curing can take place over a period of 5 to 100 minutes, preferably 10 minutes to 45 minutes.

Multi-layer coating

Another object of the present invention is a multi-layer coating, characterized in that it is obtainable after performing the inventive method for at least partially coating at least one surface of a plastic substrate with a multi-layer coating.

All the preferred embodiments described hereinbefore in connection with the coating agent system according to the invention, the coating composition according to the invention and the methods according to the invention herein are also preferred embodiments with regard to the inventive multi-layer coating.

At least partially coated substrate

Another object of the present invention is an at least partially coated with the multi-layer coating according to the invention substrate. As substrates, the previously mentioned plastic substrates are used, i. Substrates of or based on at least one plastic.

All of the coating agent system according to the invention, the coating composition according to the invention and the methods according to the invention and the inventive multi-layer coating described hereinbefore are also preferred embodiments with regard to the at least partially coated substrate according to the invention. Positioning methods

1. Determination of the non-volatile component

The non-volatile content (of the solid) is determined according to DIN EN ISO 3251 (date: June 2008). In this case, 1 g of sample are weighed into a previously dried aluminum dish and dried for 60 minutes at 105 ° C in a drying oven, cooled in a desiccator, and then weighed back. The residue based on the total amount of the sample used corresponds to the non-volatile fraction.

2. Determination of number average and weight average molecular weight The determination of the number average (M _n ) and the weight average molecular weight (M _w ) is carried out by means of gel permeation chromatography (GPC) with tetrahydrofuran as eluent and using a polystyrene standard according to ISO 13885-1: 2008. As the column material, a styrene-divinylbenzene copolymer is used. In addition, the polydispersity (ratio of weight-average molecular weight (M _w ) to number-average molecular weight (M _n )) can be determined with this method.

3. Determination of the layer thicknesses

The layer thicknesses are determined according to DIN EN ISO 2808 (date: May 2007), method 6A in section 5.4.4.2 of the standard using a measuring microscope.

4. Determination of adhesion by means of the steam jet test

The adhesion between a primer layer applied to the substrate used and an overlying basecoat and clearcoat layer is determined and evaluated by means of the method described below.

A steam jet test in accordance with DIN EN ISO 55662 (date: December 2009) is carried out. This is followed by an evaluation by means of a grading system. In this case, a steam jet is directed for one minute at a temperature of 60 ° C at 67 bar at a distance of 10 cm perpendicular to the coated substrate to be examined. Subsequently, the liability is assessed by means of a Grade system with grades 0 to 5, whereby the grade 0 is awarded for coatings which have no visible traces after the steam jet treatment (very good adhesion) and the grade 5 for coatings, which had clearly detached areas after the steam jet test (insufficient adhesion) ).

The steam jet test is carried out before weathering in a climatic chamber and once after such weathering. The weathering in the climatic chamber is carried out under storage under constant climatic conditions in accordance with DIN EN ISO 6270-2 at Prüfklima CH (date: September 2005). During storage, the coated substrates to be examined are stored for 10 days in the climatic chamber at 100% humidity and 40 ° C. The steam jet test after removal from the climatic chamber is carried out 24 hours after removal of the samples.

5. Determination of stone chip resistance

The stone chip resistance is determined and evaluated in accordance with DIN EN ISO 20567-1 B (date: July 2017). The test is always carried out on a specific position of the surface of the substrate. The assessment is based on characteristics ranging from 0 (best value) to 5 (worst value).

6. Performing a temperature cycling test (TWT)

This implementation provides for a storage of a multicoat system according to the invention or a corresponding comparative multicoat system. The temperature cycling test is carried out in 3 so-called cycles. One cycle (24) consists of storage at 105 ° C. for 15 hours, storage at 23 ° C. ± 2 ° C. for 30 minutes, storage at -40 ° C. for 8 hours and storage at 23 ° C. ± 2 for 30 minutes ° C. Subsequent to the TWT, the steam jet test described above is carried out in accordance with DIN EN ISO 55662 (date: December 2009).

7. Assessment of chemical resistance

Chemical resistance is determined and evaluated in accordance with DIN EN ISO 2812-3 (date: October 2012) or in accordance with DIN EN ISO 2812-4 (date: May 2007). The assessment is based on characteristics ranging from 0 (best value) to 5 (worst value).

8. Appearance determination

Appearance assessment is performed with a Byk / Gardner wave scan meter. For the purpose of assessing the appearance, a laser beam is directed onto the surface to be examined at an angle of 60 °, and the fluctuations of the reflected light in a so-called short wave range (0.3 to 1.2) are measured over a measuring distance of 10 cm mm) and in the so-called long wave range (1, 2 to 12 mm) with the aid of the measuring instrument (long wave = LW; short wave = SW, the lower the values, the better the appearance). In addition, as a measure of the sharpness of an image reflected in the surface of the multilayer structure, the characteristic "distinctness of imgage" (DOI) is determined with the aid of the measuring device (the higher the value, the better the appearance) The COMBFORD value determines (the higher the value, the better the appearance).

9. Perform the temperature change test PV 1200

This implementation provides storage of a multicoat system according to the invention or a corresponding comparative multicoat system under the conditions of the test specification PV 1200 of Volkswagen AG. This is followed by the steam jet test described above in accordance with DIN EN ISO 55662 (date: December 2009).

Examples and Comparative Examples

The following examples and comparative examples serve to illustrate the invention, but are not to be construed as limiting. Unless otherwise stated, the figures in parts are by weight and percentages are by weight.

1. Preparation of 2K Primer Coating Compositions P1 and P2 1.1 Stock Paint Component S1

The components described in greater detail in Table 1 .1 below are mixed homogeneously with one another in the order given there for the preparation of the basecoat component S1.

Table 1.1: Preparation of the base paint component S1

Σ 100% by weight

In the case of Pi a and P2a, the molar ratio of OH groups to NCO groups is 1: 5. In the case of P1 b and P2b, the molar ratio of OH groups to NCO groups to each other is 1: 8.

1.5 Hardener components H5a and H5b

To the comparative hardener component H1 described in 1.2 above and Table 1 .2, the commercially available product Geniosil® GF 60 (N-methyl [3- (trimethoxysilyl) propyl] carbamate) is mixed in such an amount that it resulting hardener component of this product in an amount of 5.1 wt .-% (H5a) or 9.6 wt .-% (H5b), each based on their total weight contains. H5a and H5b are hardener components used according to the invention.

By mixing the stock paint component S1 with hardener H5a or H5b, primer compositions of the series P2 according to the invention are obtained. The following mixing ratios of base lacquer to hardener are used (details are in parts by weight):

P2c: 100 parts masterbatch S1: 15.8 parts hardener H5a (according to the invention)

P2d: 100 parts master paint S1: 16.6 parts hardener H5b (according to the invention)

1.6 Hardener component H6a

The commercially available product Geniosil® GF 80 (3-glycidoxypropyltrimethoxysilane) is admixed in an amount such that the resulting hardener component of this product is admixed with the comparative hardener component H1 described in 1.2 above and Table 1 .2 of 5.1% by weight (H6a), based on their total weight. H6a is a hardener component used according to the invention.

By mixing base stock component S1 with hardener H6a, a series P2 primer composition according to the invention is obtained. The following mixing ratio of base lacquer to hardener is used (details are in parts by weight): P2e: 100 parts masterbatch S1: 15.8 parts hardener H6a (according to the invention)

1.7 Hardener components H7a and H7b

To the comparative hardener component H1 described in 1.2 above and Table 1 .2, the commercially available silane 25013VP from Wacker (hexadecyltrimethoxysilane) is mixed in such an amount that the resulting hardener component of this product in an amount of 5 , 1 wt .-% (H7a) or 9.6 wt .-% (H7b), each based on their total weight contains. H7a and H7b are hardener components used according to the invention.

By mixing the stock paint component S1 with hardener H7a or H7b, primer compositions of the series P2 according to the invention are obtained. The following mixing ratios of base lacquer to hardener are used (details are in parts by weight):

P2f: 100 parts masterbatch S1: 15.8 parts hardener H7a (according to the invention)

P2g: 100 parts of base paint S1: 16.6 parts of hardener H7b (according to the invention)

1.8 Hardener component H8a

To the comparative hardener component H1 described in 1.2 above and Table 1.2 phenyltriethoxysilane is mixed in such an amount that the resulting hardener component of this product in an amount of 5.1 wt .-% (H8a), based on their total weight, contains. H8a is a hardener component used according to the invention.

By mixing base stock component S1 with hardener H8a, a series P2 primer composition according to the invention is obtained. The following mixing ratio of base lacquer to hardener is used (details are in parts by weight):

P2i: 100 parts masterbatch S1: 15.8 parts hardener H8a (according to the invention) 1.9 Hardener components H9a and H9b

1,2-Bis (triethoxysilyl) ethane is added in such an amount to the comparative hardener component H1 described in 1.2 above and Table 1 .2 that the resulting hardener component of this product is used in an amount of 5.1 Wt .-% (H9a) or 9.6 wt .-% (H9b), each based on their total weight contains. H9a and H9b are hardener components used according to the invention.

By mixing the stock paint component S1 with hardener H9a or H9b, primer compositions of the series P2 according to the invention are obtained. The following mixing ratios of base lacquer to hardener are used (details are in parts by weight):

P2j: 100 parts masterbatch S1: 15.8 parts hardener H9a (according to the invention)

P2k: 100 parts base paint S1: 16.6 parts hardener H9b (according to the invention)

1.10 Hardener components H10a and H10b

To the comparative hardener component H1 described in 1.2 above and Table 1.2, the reaction product of 3 parts Dynasylan® 1124 (bis (trimethoxysilylpropyl) amine) with Desmodur® N 3300 is mixed in such an amount that the resulting hardener component this product in an amount of 2.6 wt .-% (H10a) or 5.1 wt .-% (H10b), each based on their total weight contains. H10a and H10b are hardener components used according to the invention.

By mixing the stock paint component S1 with hardener H10a or H10b, primer compositions of the series P2 according to the invention are obtained. The following mixing ratios of base lacquer to hardener are used (details are in parts by weight):

P2I: 100 parts masterbatch S1: 15.4 parts hardener H10a (according to the invention)

P2m: 100 parts master paint S1: 15.8 parts hardener H10b (according to the invention) 2. Aqueous 1K basecoats used

2.1 Basecoat B1

Basecoat B1 is a commercially available aqueous 1 K basecoat which contains at least one coloring pigment as a red pigment (commercial product ColorBrite® Jupiterrot).

2.2 Basecoat B2

Basecoat B2 is a commercially available aqueous metallic 1K basecoat containing as at least one effect pigment a commercially available aluminum pigment (commercial product ColorBrite® AC polar silver).

2.3 Basecoat B3

Basecoat B3 is a commercially available aqueous 1 K basecoat containing at least one coloring pigment as a green pigment (commercial product ColorBrite® AC Elbaite Green).

2.4 Basecoat B4

Basecoat B4 is a commercially available 1K aqueous basecoat from the ColorBrste® series which contains at least one coloring pigment as a black pigment.

3. Preparation of 2K clearcoats K1 and K2

A commercially available solvent-containing 2K clearcoat (KL) is used which is prepared by mixing together a basecoat component comprising at least one OH-functional poly (meth) acrylate and a hardener component comprising at least one free polyisocyanate (commercial product Evergloss® 906). , The basecoat component of this commercially available clearcoat is referred to below as "basecoat component S2." The hardener component of this commercially available clearcoat is referred to below as "hardener component H3". The hardener component H3 used is the same hardener component which has been described above in connection with the primer under point 1.2 as hardener component H1. Alternatively, in some cases instead of H3, a hardener component H4 is used instead. As a hardener Component H4 is the same hardener component used in the above

Connection with the primer under point 1.3 has been described as hardener component H2.

By mixing base stock component S2 with hardener H3 or H4

Clearcoat compositions of the series K1 (S2H3) or the series K2 (S2H4).

The following mixing ratios of base lacquer to hardener are used (details are in parts by weight):

K1 a: 100 parts base paint S2: 35 parts hardener H3

K2a: 100 parts base paint S2: 37.5 parts hardener H4.

4.2 Production of coated substrates

4.2.1 Plastic substrates are used as substrates, each in the form of test plates with an area of 10 cm x 14 cm x 0.3 cm. Substrates made of PP / EPDM (polypropylene / ethylene-propylene-diene rubber, Sabic® 8500) (substrate T1) are used as plastic substrates. In addition, a number of other substrates are used, namely PC / PBT (polycarbonate / polybutylene terephthalate, Bayblend® T 65 XF 901510, T2), PC / ABS (polycarbonate / acrylonitrile butadiene styrene, Xenoy® CL101 D black, T3), PUR / RIM (polyurethane / Reaction Injection Molding (T4) and CFRP (Carbon Fiber Reinforced Plastic, T5). Substrate T1 is blasted three times with a propane burner at a slow belt speed (0.45 ± 0.2 m / sec) and 5.2 + 0.2 cm apart at a gas flow rate setting of 5.2 ± 0.2 L / min and air = 125 ± 5 L / min lit.

4.2.2 Subsequently, the pretreated substrates T1 to T5 are successively coated with a primer composition of the series P1 or P2, a basecoat B1 or B2 or B3 and a clearcoat of the series K1 or K2.

Several different process variants are carried out: Variant vi:

vi comprises the following sub-steps:

A P1 or P2 series primer is applied to the substrate and then dried for 10 minutes at room temperature (20 ° C) with circulating air. Then it is cured for 30 minutes at 80 ° C (object temperature). The basecoat is then applied and dried for 10 minutes at room temperature (20 ° C) with circulating air. Then it is cured for 10 minutes at 80 ° C. Subsequently, a clear coat of the series K1 or K2 is applied and dried for a period of 10 minutes at room temperature (20 ° C) with circulating air. Then it is cured for 30 minutes at 80 ° C.

Variant v2:

v2 comprises the following sub-steps:

A P1 or P2 series primer is applied to the substrate and then dried for 10 minutes at room temperature (20 ° C) with circulating air. The basecoat is then applied and dried for 10 minutes at room temperature (20 ° C) with circulating air. Subsequently, a clear coat of the series K1 or K2 is applied and dried for a period of 10 minutes at room temperature (20 ° C) with circulating air. Then all layers are cured together for a period of 30 minutes at 90 ° C (object temperature).

Variant v3:

v3 comprises the following sub-steps:

A P1 or P2 series primer is applied to the substrate and then dried for 10 minutes at room temperature (20 ° C) with circulating air. The basecoat is then applied and dried for 15 minutes at room temperature (20 ° C) with circulating air. Subsequently, a clear coat of the series K1 or K2 is applied and dried for a period of 10 minutes at room temperature (20 ° C) with circulating air. Then all layers are cured together for a period of 30 minutes at 90 ° C (object temperature). Variant v4:

v4 comprises the following sub-steps:

A P1 or P2 series primer is applied to the substrate and then dried for 10 minutes at room temperature (20 ° C) with circulating air. The basecoat is then applied and dried for 15 minutes at room temperature (20 ° C) with circulating air. Subsequently, a clear coat of the series K1 or K2 is applied and dried for a period of 10 minutes at room temperature (20 ° C) with circulating air. Then all layers are cured together for a period of 40 minutes at 80 ° C (object temperature).

Variant v5:

v5 comprises the following sub-steps:

A P1 or P2 series primer is applied to the substrate and then dried for 10 minutes at room temperature (20 ° C) with circulating air. The basecoat is then applied and dried for 10 minutes at room temperature (20 ° C) with circulating air. Subsequently, a clear coat of the series K1 or K2 is applied and dried for a period of 10 minutes at room temperature (20 ° C) with circulating air. Then all layers are cured together for a period of 40 minutes at 80 ° C (object temperature).

Variant v6:

v6 comprises the following sub-steps:

A P1 or P2 series primer is applied to the substrate and then dried for 15 minutes at room temperature (20 ° C) with circulating air. Subsequently, basecoat is applied and dried for 10 minutes at room temperature (20 ° C) with circulating air. Subsequently, a clear coat of the series K1 or K2 is applied and dried for a period of 10 minutes at room temperature (20 ° C) with circulating air. Then all layers are cured together for a period of 40 minutes at 80 ° C (object temperature).

In each of the variants, the primer series P1 or P2 in a dry film thickness of 10 to 15 pm, the basecoat B1 or B2 or B3 in a Dry layer thickness of 11 to 25 μιτι and Klariack the series K1 or K2 applied in a dry film thickness of 25 to 35 μιτι.

5. Investigation of the properties of the coated substrates

Various application-technological properties of the resulting multicoat paint systems were investigated. The investigation was carried out according to the methods described above. In the following tables 4a to 4k, these results are summarized. The results given are the average values from 4 to 8 determinations (and are therefore partially indicated with decimal places).

Table 4a: a substrate T1 was used as substrate in each case

A comparison of the results for the abutments 4 vs. Figure 5 shows that better results have been achieved for the multi-layer coatings prepared using a primer coating composition of the present invention, in particular with respect to chemical resistance to pancreatin, than with corresponding comparative primer coating compositions.

Table 4c: a substrate T1 was used as substrate in each case

A comparison of the results for the abutments 4 vs. 5 and 6 vs. 7 shows that better results have been achieved for the multicoat paint systems which have been prepared by means of a primer coating composition according to the invention, in particular with regard to the appearance in LW, than with corresponding comparative primer coating compositions. Table 4d: a substrate T1 was used as substrate in each case

A comparison of the results for the constructions 8 vs. Figure 9 shows that better results were achieved for the multi-layer coatings prepared using a primer coating composition of the present invention, particularly with respect to LW appearance, than with corresponding comparative primer coating compositions.

Tab. 4e: Use of various substrates

A comparison of the results for the structures 10 to 14 shows that for the multi-layer coatings, which have been prepared by means of a primer coating composition according to the invention, good results are obtained for different plastic substrates. Table 4f: a substrate T1 was used as substrate in each case

The results show good results for both setups 15 and 16.

Table 4g: a substrate T1 was used as substrate in each case

A comparison of the results for the structures 17 vs. FIG. 18 shows that, for the multicoat paint systems which have been produced by means of a primer coating composition according to the invention, in particular with regard to

A comparison of the results for the abutments 21 vs. Figure 22 shows that for the multi-layer coatings made using a primer coating composition of the present invention, better results have been achieved, particularly with respect to the KK vapor-blasting test, than with the corresponding comparative primer coating composition.

Table 4j: a substrate T1 was used as substrate in each case

The results show good results for both setups 23 and 24.

Table 4k: a substrate T1 was used as substrate in each case

Multilayer 25 26 27

paint (fiction (inventive (non-construction according to) according to) according to the invention)

Primer P2I P2m Pi a

Basecoat B4 B4 B4

Clearcoat K1 a K1 a K1 a

Process variant v2 v2 v2

Results

Steam jet test before 0.2 0.2 0

KK

Steam radiated to 0.6 0.8 2

KK

Steam jet test after 0.2 0.2 0

PV1200 A comparison of the results for the structures 25 and 26 vs.. Figure 27 shows that for the multi-layer coatings made using a primer coating composition of the present invention, better results have been achieved, particularly with respect to the KK vapor jet test, than with the corresponding comparative primer coating composition.

Claims

claims:

1 . A use of a primer coating composition obtainable by combining at least two mutually different and separate components (A) and (B) of a coating agent system wherein component (A) is aqueous, containing at least one polymer (a1) which faces Isocyanate groups having reactive functional groups, and containing at least one pigment (a2) and / or at least one filler (a3), and wherein component (B) is non-aqueous and at least one polyisocyanate (b1) having more than two free isocyanate Contains groups and at least one organic solvent (b2), characterized in that component (B) also contains at least one Si-containing compound (b3) having at least one hydrolysable radical and at least one non-hydrolyzable organic radical, at least partially Application to at least one optionally pretreated surface of a plastic sub strats.

2. The use according to claim 1, characterized in that component (B) contains at least one Si-containing compound (b3), whose at least one non-hydrolyzable organic radical is selected from the group consisting of aliphatic radicals having 1 to 24 carbon atoms , cycloaliphatic radicals having from 3 to 12 carbon atoms, aromatic radicals having from 6 to 12 carbon atoms and araliphatic radicals having from 7 to 18 carbon atoms, each of these radicals optionally having at least one isocyanate-reactive functional group, this group in turn optionally masked with at least one cleavable under hydrolytic conditions protecting group.

7. The use according to one of the preceding claims, characterized in that as polymer (a1) at least one OH-functional polymer selected from the group consisting of polyurethanes, polyureas, polyesters, polyamides, polyethers, poly (meth) acrylates and / or copolymers the said polymers is used.

8. The use according to one of the preceding claims, characterized in that the coating agent system consists of the two components (A) and (B) or in addition to the two components (A) and (B) another, of (A) and (B ) comprises different and also separately from (A) and (B) present and used for dilution component (C) comprising one or more organic solvents and / or water.

9. The use according to one of the preceding claims, characterized in that the components (A) and (B) within the coating agent system to one another such that the NCO content of the primer coating composition by combining at least the two components (A) and (B) preparable, based on their total solids, in a range of 1 to 12% by weight.

10. A method for at least partially coating at least one surface of a plastic substrate with a primer, characterized in that the method comprises at least one step (1), namely

(1) at least partially applying the primer coating composition as defined in any one of claims 1 to 9 to at least one optionally pretreated surface of a plastic substrate.

11. A method for at least partially coating at least one surface of a plastic substrate with a multi-layer coating, characterized in that the method comprises at least the following steps (1) to (7), namely

(1) a step (1) as defined in claim 10,

(5) applying a clearcoat composition to the at least one basecoat film obtained after step (4),

12. The method according to claim 11, characterized in that the intermediate drying steps (2), (4) and (6) in each case by air supply at room temperature and the air velocity is at least 0.3 m / s.

The method according to claim 11 or 12, characterized in that it is a 3C1 B method in which exactly one basecoat composition is applied within step (3).

14. A multi-layer coating, characterized in that it is obtainable after carrying out the method according to one of claims 11 to 13.

15. An at least partially coated with the multi-layer coating according to claim 14 plastic substrate.