EP3601456A1

EP3601456A1 - Aqueous color pigment pastes containing a polymerizate, and basecoats produced therefrom

Info

Publication number: EP3601456A1
Application number: EP18711381.6A
Authority: EP
Inventors: Dirk EIERHOFF; Jörg Schwarz; Stephan Schwarte; Cathrin CORTEN
Original assignee: BASF Coatings GmbH
Current assignee: BASF Coatings GmbH
Priority date: 2017-03-23
Filing date: 2018-03-22
Publication date: 2020-02-05
Also published as: CN110431199A; US20200140713A1; WO2018172476A1; US11299647B2; JP2020511582A; JP7143318B2; CN110431199B; MX2019011308A

Abstract

The present invention relates to an aqueous pigment paste comprising at least one color pigment (a) and at least one polymerizate (b) which can be produced by the sequential radical emulsion polymerization of three monomer mixtures (A), (B) and (C) of olefinically unsaturated monomers in water. The invention also relates to an aqueous basecoat which can be produced by admixing the pigment paste with at least one aqueous binder-containing component that is suitable for producing the basecoat. The invention further relates to a method for producing a multi-layer paint using said basecoat and to a use of the polymerizate (b) for dispersing color pigments within an aqueous pigment paste.

Description

Aqueous color pigment pastes containing a polymer and therefrom

prepared basecoats

The present invention relates to an aqueous pigment paste comprising at least one color pigment (a) and at least one polymer (b) which can be prepared by successive free-radical emulsion polymerization of three monomer mixtures (A), (B) and (C) of olefinically unsaturated monomers in water, an aqueous basecoat which can be prepared by admixing the pigment paste to at least one aqueous binder-containing component suitable for the preparation of the basecoat, a process for producing a multicoat system using this basecoat, and a use of the polymerizate (b) for dispersing color pigments within an aqueous pigment paste.

State of the art

Pigment pastes and polymers used therein are known in the art. Through the use of pigment pastes, the technically complex process of pigment dispersion is substantially facilitated in the paint industry, since it ensures, for example, dust-free processing of pigments during the formulation of paints. In addition, the pigments are optimally wetted by incorporation into the paste and very well dispersed, so that an improved distribution state is achieved in the resulting paint. This results in improved application-technological properties of the paint and the coating produced therefrom, for example, a particularly homogeneous color or color distribution of the paint. For these reasons, pigment pastes are first prepared separately as an intermediate before incorporation into a paint such as a water-based paint.

In the preparation of pigment pastes, precisely matched polymers must be used as paste binders to obtain an optimally conditioned paste. Without an individual adaptation and precise selection of the polymer, the respective pigment can usually not be optimally dispersed, so that it also the application technological properties of the ultimately resulting paint are not optimal.

In addition, it is often problematic here that the corresponding paste binder does not always correspond to the main binder of the coating composition, so that a further binder component is introduced into the coating agent by the paste. As a result, the manufacturing process of the coating composition becomes more complex. In addition, you lose in the paint production on formulation freedom. Because by the use of a certain polymer in the paste, if necessary, other coating components must in turn also be matched to this polymer. In addition, there is less scope for the use of further additives and / or binder components in the coating, since in particular the proportion of the primary binder of primary importance can be lowered too much. Attempts to compensate for the above disadvantages in terms of freedom from formulation by using in the paste, a polymer (paste binder), which corresponds to the main binder in the resulting coating composition, must usually compromise on the choice of the main binder and thus the quality of the resulting coating composition and the received with multi-layer coating produced, but this is undesirable.

From an ecological point of view, it is also desirable to use pigment pastes which are aqueous or have the lowest possible content of organic solvents.

From WO 2015/09081 A1, aqueous pigment pastes are known which, in addition to a pigment, contain a polyurethane-based copolymer which can be prepared by copolymerization of a mixture of olefinically unsaturated monomers in the presence of a polyurethane. However, the pigment pastes disclosed in WO 2015/09081 1 A1 do not always lead to the desired pinhole robustness after incorporation into a coating agent such as a water-based lacquer.

Pigment pastes which contain, for example, polyesters and / or polyurethanes and often comparatively high amounts of organic solvents are also known in the prior art. However, a disadvantage of these pigment pastes their low storage stability and their comparatively high solvent and binder content. In addition, coating compositions, in particular basecoats, into which such pigment pastes have been incorporated, or coatings obtained from such coating compositions, often do not always have sufficient properties with regard to hiding power, storage stability, speckling, tendency to segregation, emergence of cookers and / or runners and Pin-prickle robustness, on. Polyurethane-containing pigment pastes are known, for example, from EP 1 448 730 B1, EP 0 960 174 B1 and WO 91/15528 A1. Polyester polyurethane-containing pigment pastes are known, for example, from EP 0 438 090 B1.

There is therefore a need for aqueous pigment pastes which do not have the aforementioned disadvantages.

task

It is therefore an object of the present invention to provide an aqueous pigment paste which can be used for the preparation of a basecoat and which has advantages over the pigment pastes known from the prior art. In particular, it is an object of the present invention to provide an aqueous pigment paste containing as paste binder a polymer which can likewise be used in corresponding aqueous basecoats produced using the pigment paste as main binder. The aqueous basecoats produced in this way should optimally fulfill the required application-technological properties, in particular a good visual appearance and hiding power, if not improve them, but in no case worsen them.

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 subject of the present invention is therefore an aqueous pigment paste comprising

(a) at least one color pigment and

(B) at least one polymer having an average particle size in

Range of 100 to 500 nm, preparable by successive free radical emulsion polymerization of three monomer mixtures (A), (B) and (C) of olefinically unsaturated monomers in water, wherein

the mixture (A) contains at least 50% by weight of monomers having a solubility in water of less than 0.5 g / l at 25 ° C, and a polymer prepared from the mixture (A) has a glass transition temperature of from 10 to 65 ° C, the mixture (B) contains at least one polyunsaturated monomer and a polymer which is prepared from the mixture (B) has a glass transition temperature of -35 to 15 ° C, and

a polymer prepared from the mixture (C) has a glass transition temperature of -50 to 15 ° C,

and where

i. first the mixture (A) is polymerized, ii. then the mixture (B) in the presence of under i. polymerized polymerized, and

iii. then the mixture (C) in the presence of under ii. polymerized polymerized.

A further subject matter of the present invention is an aqueous basecoat, wherein the basecoat material can be prepared by mixing at least one pigment paste according to the invention as component (1) to at least one aqueous component (2) suitable for the preparation of a basecoat, which contains at least one polymer usable as a binder, wherein this polymer which can be used as a binder is the polymer (b) also present in the pigment paste and / or at least one polymer which is different therefrom. As can be seen from the results of point 5.5 and table 5.13 of the As can be seen from the experimental part described below, the basecoats according to the invention differ in their properties, for example with regard to long wave (LW) and DOI, ie with regard to their appearance, by this special preparation of base coats of the same composition but which have been prepared by other means. in the determination of the layer thickness-dependent course.

Another object of the present invention is a process for producing a multi-layer coating, in which

(1a) an aqueous basecoat is applied to a substrate,

(2a) a polymer film is formed from the lacquer applied in step (1a),

(1 b) optionally on the polymer film thus formed a further aqueous

Basecoat is applied,

(2b) if appropriate, a polymer film is formed from the paint applied in step (1b),

(3) a clearcoat is applied to the basecoat layer (s) so obtained, and then

(4) the basecoat film (s) together with the clearcoat film is / are cured together, which is characterized in that a basecoat material according to the invention in step (1 a) or - if the process also stages (1 b) and (2b ) - in step (1 a) and / or (1 b) is used. The substrate used in step (1a) preferably has an electrodeposition coating layer (ETL), more preferably an electrodeposition coating layer applied by cathodic deposition of an electrodeposition coating, and the basecoat used in step (1a) is applied directly to the ETL-coated substrate. wherein the electrodeposition coating layer (ETL) applied to the substrate is preferably cured when performing step (1a).

A further subject of the present invention is a use of the polymer (b) mentioned in connection with the first subject, ie a polymer having an average particle size in the range from 00 to 500 nm, preparable by successive free radical emulsion polymerization of three monomer mixtures (A), (B) and (C) of olefinically unsaturated monomers in water, the mixture (A) at least 50 wt .-% of monomers having a solubility in water of less than 0.5 g / l at 25 ° C and a polymer prepared from the mixture (A) has a glass transition temperature of 10 to 65 ° C,

the mixture (B) contains at least one polyunsaturated monomer and a polymer which is prepared from the mixture (B), a

Glass transition temperature of -35 to 15 ° C has, and

a polymer prepared from the mixture (C), a

Glass transition temperature of -50 to 15 ° C has,

and where

i. first the mixture (A) is polymerized,

ii. then the mixture (B) in the presence of under i. polymerized polymerized, and

iii. then the mixture (C) in the presence of under ii. polymerized polymerized to disperse color pigments within an aqueous pigment paste.

It has surprisingly been found that the polymer (b) present in the aqueous pigment paste according to the invention can be used not only as the main binder in aqueous basecoats, but also as a paste binder in an aqueous pigment paste. As a result, in the production of the basecoat, improved freedom of formulation is obtained since the other coating components of the basecoat do not have to be matched to a further paste binder other than the polymer (b) due to the now permitted use of the polymer (b) in the pigment paste. In addition, there is more scope for the use of further additives and / or binder components in the basecoat, since the proportion of the main binder of the basecoat in these cases is not lowered too far by the use of the polymer (b) in the pigment paste. In particular, it has surprisingly been found that despite use of the polymer (b) both as paste binder in the pigment paste and as the main binder of the resulting basecoat no disadvantages in the quality of the resulting coating composition and the multicoat paint systems produced therewith occur, for example with respect to application-technological properties such as a good visual appearance (appearance, appearance of stoves and runners, as well as pinpricks and specks) and in terms of hiding power.

Detailed description

The term "comprising" in the context of the present invention in connection with the pigment paste according to the invention and also in connection with the basecoat according to the invention preferably has the meaning "consisting of". In this connection, one or more of the other constituents mentioned below may optionally be mentioned in addition to the components (1), (2) and water, both with regard to the pigment paste of the invention and components (a), (b) and water The components of the pigment paste according to the invention and / or the basecoat material according to the invention may be contained in this or this. All components can be present in each case in their preferred embodiments mentioned below.

Inventive pigment paste

The pigment paste according to the invention is a color pigment paste due to the presence of the at least one color pigment (a). The term pigment paste is known to the person skilled in the art and is defined, for example, in Rompp Lexikon, Paints and Printing Inks, Georg Thieme Verlag, 1998, 10th Edition, page 452: Pigment pastes are preparations of pigment mixtures in support materials such as polymers in which the pigments are in a higher concentration present as it corresponds to the later application. The subsequent use of pigment pastes is usually in the production of coating materials such as basecoats. A pigment paste is thus to be distinguished from a coating agent such as a basecoat in that it is merely a precursor for the preparation of a represents such coating agent. A pigment paste as such can therefore not be used as a basecoat itself. In pigment pastes, the relative weight ratio of pigments to polymers is usually greater than in the coating compositions, for the production of which the paste is finally used. In addition to the support materials such as polymers, which are also known as paste binders, and pigments, water and / or organic solvents are usually present in the pigment paste. Also, various additives such as wetting agents and / or thickeners can be used in a pigment paste. The polymer (b) present in the pigment paste of the invention is used as a pigment paste binder (paste binder). The pigment paste according to the invention is an aqueous composition containing components (a) and (b).

The pigment paste according to the invention is aqueous. It is preferably a system containing as solvent mainly water, preferably in an amount of at least 25 wt .-%, and organic solvents in minor proportions, preferably in an amount of <25 wt .-%, in each case based on the total weight of the pigment paste according to the invention.

Preferably, the pigment paste of the invention contains a proportion of water of at least 25 wt .-%, more preferably of at least 30 wt .-%, most preferably of at least 35 wt .-%, in particular of at least 40 wt .-%, most preferably of at least 42.5 wt .-%, each based on the total weight of the pigment paste.

The pigment paste according to the invention preferably contains a proportion of water which ranges from 25 to 75% by weight, more preferably from 30 to 70% by weight, most preferably from 35 to 65% by weight. % or up to 60 wt .-% or up to 55 wt .-%, each based on the total weight of the pigment paste.

Preferably, the pigment paste according to the invention contains a proportion of organic solvents which is in a range of <25 wt .-%, more preferably in a range of 0 to <25 wt .-%, most preferably in a range of 0.5 to 25 wt .-% or to 15 wt .-% or to 10 wt .-%, each based on the total weight of the pigment paste.

Preferably, the solids content of the pigment paste according to the invention is in a range of 15 to 70 wt .-%, particularly preferably from 17.5 to 65 wt .-%, most preferably from 20 to 60 wt .-%, in particular from 22.5 to 55 wt .-%, most preferably from 25 to 50 wt .-% or from 30 to 50 wt .-%, each based on the total weight of the pigment paste. The determination of the solids content, ie the non-volatile content, is carried out according to the method described below.

Preferably, the percentage sum of the solids of the pigment paste according to the invention and the proportion of water in the pigment paste of the invention is at least 70 wt .-%, preferably at least 80 wt .-%. Preferred among these are ranges from 70 to 99% by weight, in particular 75 or 80 to 97.5% by weight. For example, if a pigment paste according to the invention has a solids content of 30% by weight and a water content of 65% by weight, the percentage sum of the solids and the proportion of water defined above is 95% by weight.

Preferably, the pigment paste according to the invention contains a proportion of polymer (b) in a range from 1, 0 to 25 wt .-%, particularly preferably from 1, 5 to 20 wt .-%, most preferably from 2.0 to 17.5 Wt .-%, in particular from 2.5 to 15 wt .-%, most preferably from 4.0 to 12.5 wt .-%, each based on the total weight of the pigment paste. The determination or determination of the proportion of the polymer (b) on the pigment paste can be carried out by determining the solids content (also called non-volatile content, solids content or solids content) of an aqueous dispersion containing the polymer (b), which is used to prepare the pigment paste becomes.

The pigment paste according to the invention preferably contains a proportion of color pigment (a) of at least 5% by weight, preferably of at least 7.5 or 10% by weight, particularly preferably of at least 12.5 or 15% by weight, completely particularly preferably of at least 17.5% by weight, in particular of at least 20 or 22.5 or 25 or 27.5% by weight, most preferably of at least 30% by weight, in each case based on the total weight of the pigment paste, in particular when the color pigment (a) is a white pigment such as titanium dioxide.

The pigment paste according to the invention preferably contains a proportion of color pigment (a) in a range from 5 to 75% by weight, particularly preferably from 7.5 to 70% by weight, very particularly preferably from 10 to 65% by weight, in particular from 15 to 60% by weight, most preferably from 17.5 to 55% by weight or from 20 to 50% by weight, based in each case on the total weight of the pigment paste, in particular when the color pigment (a) a white pigment like titanium dioxide.

Preferably, the relative weight ratio of the at least one color pigment (a) to the polymer (b) in the pigment paste is at least 1: 1 or at least 1.2: 1 or at least 1.5: 1 or higher, more preferably at least 2.0: 1 or higher, most preferably at least 2.5: 1 or higher, especially at least 3.0: 1 or higher.

Preferably, the relative weight ratio of the at least one color pigment (a) to the polymer (b) in the pigment paste is in a range from 15: 1 to 1:15, more preferably in a range from 10: 1 to 1:10, most preferably in a range of 8: 1 to 1: 8. In particular, when the at least one color pigment (a) is a white pigment such as titanium dioxide, the relative weight ratio of the at least one color pigment (a) to the polymer (b) in the pigment paste is preferably in a range of 10: 1 to 1: 1 or from 10: 1 to 1, 2: 1 or from 10: 1 to 1, 5: 1, more preferably in a range from 8: 1 to 1, 2: 1 or from 8: 1 to 1, 5: 1, all more preferably in a range from 8: 1 to 1, 7: 1 or from 8: 1 to 2.0: 1, in particular in a range from 8: 1 to 2.2: 1 or from 8: 1 to 2.5 :1 .

The proportions in% by weight of all components (a), (b) and water present in the pigment paste of the invention and further, if appropriate, in addition existing components add up to 100 wt .-%, based on the total weight of the pigment paste.

Color pigment (a)

The pigment paste according to the invention contains at least one color pigment as component (a), preferably in an amount of at least 5% by weight, based on the total weight of the pigment paste.

A person skilled in the art is familiar with the concept of color pigments. The terms "coloring pigment" and "color pigment" are interchangeable within the meaning of the present invention. A corresponding definition of the pigments and further specifications thereof is regulated in DIN 55943 (date: October 2001). As the color pigment (a), inorganic and / or organic pigments can be used. Preferably, the color pigment (a) is an inorganic color pigment. Particularly preferred color pigments (a) used are white pigments, colored pigments and / or black pigments. White pigments are the most preferred. 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 sulphoselenide, 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.

The pigment paste according to the invention may optionally contain from the at least one color pigment (a) various further pigments, in particular effect pigments, and / or fillers. However, the pigment paste according to the invention preferably contains no such further pigment as an effect pigment and also no filler. Polymer (b)

The pigment paste according to the invention comprises at least one polymer (b) having an average particle size in the range from 100 to 500 nm, preparable by successive free radical emulsion polymerization of three monomer mixtures (A), (B) and (C) of olefinically unsaturated monomers in water, the Mixture (A) at least 50 wt .-% of monomers having a solubility in water of less than 0.5 g / l at 25 ° C and a polymer which is prepared from the mixture (A), a glass transition temperature of 10 to 65 Has ° C,

Glass transition temperature of -35 to 15 ° C has, and

a polymer prepared from the mixture (C), a

Glass transition temperature of -50 to 15 ° C has,

and where

i. first the mixture (A) is polymerized,

iii. then the mixture (C) in the presence of under ii. polymerized polymerized.

The polymers (b) are so-called seed-core-shell polymers (SCS-Pokymerisate). Polymers (b) or aqueous dispersions containing such polymers are known for example from WO 2016/1 16299 A1. Preferably, the polymer (b) is a (meth) acrylic copolymer.

The polymer (b) present in the pigment paste of the invention is used as a pigment paste binder (paste binder). For the purposes of the present invention, the term "binder" in accordance with DIN EN ISO 4618 (German version, date: March 2007) preferably contains the non-volatile components responsible for film formation of a composition such as the pigment paste according to the invention or the basecoat according to the invention, with the exception of the pigments contained therein, such as the at least one color pigment (a) and any other pigments and / or fillers present. The non-volatile portion can be determined according to the method described below. A binder component is accordingly a specific component which contributes to the binder content of a composition such as the pigment paste of the invention or the basecoat of the invention. An example which may be mentioned is a basecoat containing the polymer (b), a crosslinking agent such as a melamine resin and / or a free or blocked polyisocyanate and / or a polymeric additive.

The polymer (b) is preferably used in the form of an aqueous dispersion for the preparation of the pigment paste according to the invention.

The preparation of the polymer (b) comprises the successive free radical emulsion polymerization of three mixtures (A), (B) and (C) of olefinically unsaturated monomers, each in water. It is therefore a multi-stage radical emulsion polymerization, wherein i. first the mixture (A) is polymerized, then ii. in the presence of under i. polymer prepared, the mixture (B) is polymerized and further iii. in the presence of under ii. produced polymerizate the mixture (C) is polymerized. All three monomer mixtures are thus polymerized via a separately carried out free radical emulsion polymerization (that is, stage or polymerization stage), wherein these stages take place in succession. The stages can - in terms of time - take place directly behind each other. It is also possible that after completion of a stage, the corresponding reaction solution stored for a certain period of time and / or transferred to another reaction vessel and only then the next stage is performed. Preferably, the preparation of the polymer (b) in addition to the polymerization of the monomer mixtures (A), (B) and (C) comprises no further polymerization.

The term radical emulsion polymerization is known to the person skilled in the art and will be explained in more detail below. In the polymerization olefinically unsaturated monomers in an aqueous medium, preferably using at least one water-soluble initiator and polymerized in the presence of at least one emulsifier. Corresponding water-soluble initiators are likewise known. The at least one water-soluble initiator is preferably selected from the group consisting of potassium, sodium or ammonium peroxodisulfate, hydrogen peroxide, tert-butyl hydroperoxide, 2,2'-azobis (2-amidoisopropane) dihydrochloride, 2,2-azobis (N, N'-dimethyleneisobutyr- amidine) dihydrochloride, 2,2'-azobis (4-cyanopentanoic acid) and mixtures of the aforementioned initiators, for example hydrogen peroxide and sodium persulfate. Also belonging to the preferred group mentioned are the known redox initiator systems. Redox initiator systems are in particular those initiators which comprise at least one peroxide-containing compound in combination with at least one redox coinitiator, for example reducing sulfur compounds such as bisulfites, sulfites, thiosulfates, dithionites or tetrathionates of alkali metals and ammonium compounds, sodium hydroxymethanesulfinate dihydrate and / or thiourea. Thus one can use combinations of peroxodisulfates with alkali metal or ammonium hydrogen sulfites, for example ammonium peroxydisulfate and ammonium bisulfite. The weight ratio of peroxide-containing compounds to the redox coinitiators is preferably 50: 1 to 0.05: 1.

In addition, transition metal catalysts can be used in combination with the initiators, such as, for example, iron, nickel, cobalt, manganese, copper, vanadium or chromium salts, such as iron (II) sulfate, cobalt (I) chloride, nickel (II) sulfate, cuprous chloride, manganese-ll-acetate, vanadium-lll-acetate, manganese-ll-chloride. Based on the total mass of the olefinically unsaturated monomers used in a polymerization, these transition metal salts are usually used in amounts of from 0.1 to 1000 ppm. Thus, one can use combinations of hydrogen peroxide with iron-II salts, such as 0.5 to 30 wt .-% hydrogen peroxide and 0.1 to 500 ppm Mohr's salt, the proportions in each case based on the total weight of the employed in the respective polymerization Are monomers. The initiators are preferably in an amount of 0.05 to 20 wt .-%, preferably 0.05 to 10, particularly preferred from 0.1 to 5 wt .-%, based on the total weight of the monomers used in the respective polymerization stage used.

An emulsion polymerization proceeds in a reaction medium containing water as a continuous medium and more preferably at least one emulsifier, preferably in the form of micelles. The polymerization is started by decomposition of the water-soluble initiator in the water. The growing polymer chain inserts into the emulsifier micelles and further polymerization then takes place in the micelles. In addition to the monomers, the at least one water-soluble initiator and the at least one emulsifier, the reaction mixture therefore preferably consists mainly of water. The components mentioned, that is to say monomers, water-soluble initiator, emulsifier and water, preferably account for at least 95% by weight of the reaction mixture. The reaction mixture preferably consists of these components. The at least one emulsifier is preferably in an amount of 0.1-10 wt .-%, more preferably 0.1 to 5 wt .-%, most preferably 0.1 to 3 wt .-%, each based on the Total weight of the monomers used in the respective polymerization stage used. Emulsifiers are also known in principle. It is possible to use nonionic or ionic emulsifiers, including zwitterionic, if appropriate also mixtures of the abovementioned emulsifiers. Preferred emulsifiers are optionally ethoxylated and / or propoxylated alkanols having 10 to 40 carbon atoms. They may have different degrees of ethoxylation or propoxylation (for example, adducts modified with poly (oxy) ethylene and / or poly (oxy) propylene chains consisting of 5 to 50 molecular units). It is also possible to use sulfated, sulfonated or phosphated derivatives of the products mentioned. Such derivatives are usually used in neutralized form. Particularly preferred emulsifiers are neutralized Dialkylsulfosuccinic or Alkyldiphenyloxiddisulfonate suitable, for example, commercially available as EF-800 Fa. Cytec. The emulsion polymerizations are advantageously carried out at a temperature of 0 to 160 ° C, preferably from 15 to 95 ° C, more preferably 60 to 95 ° C. In this case, it is preferable to operate with the exclusion of oxygen, preferably under an inert gas atmosphere. In general, the polymerization is carried out at atmospheric pressure, but is also the application of lower pressures or higher pressures possible. In particular, when polymerization temperatures are used which are above the boiling point of water at normal pressure, the monomers used and / or the organic solvents, higher pressures are generally selected.

The individual polymerization stages in the preparation of the polymer (b) can be carried out, for example, as so-called "starving polymerizations" (also known as "starve feed", "starve fed" or "starved feed" polymerizations). As starving polymerization in the context of the present invention, an emulsion polymerization is considered in which the content of free olefinically unsaturated monomers in the reaction solution (also called reaction mixture) is minimized during the entire reaction time. This means that the addition of the olefinically unsaturated monomers takes place in such a way that in the reaction solution, a proportion of free monomers of 6.0 wt .-%, preferably 5.0 wt .-%, particularly preferably 4.0 wt .-%, especially advantageously 3.5 wt .-%, in each case based on the total amount of the monomers used in the respective polymerization, is not exceeded during the entire reaction time. Of these, even more preferred are concentration ranges of the olefinically unsaturated monomers of 0.01 to 6.0 wt .-%, preferably 0.02 to 5.0 wt .-%, particularly preferably 0.03 to 4.0 wt .-%, in particular 0.05 to 3.5 wt .-%. For example, the highest proportion by weight to be detected during the reaction at 0.5 wt .-%, 1, 0 wt .-%, 1, 5 wt .-%, 2.0 wt .-%, 2.5 wt .-% or 3.0 wt .-%, while all other detected values are then below the values given here. The total amount (also called total weight) of the monomers used in the respective polymerization stage corresponds to stage i. apparently the total amount of monomer mixture (A), for stage ii. the total amount of the monomer mixture (B) and for stage iii. the total amount of the monomer mixture (C). The concentration of the monomers in the reaction solution can be determined, for example, by gas chromatography. In this case, a sample of the reaction solution is cooled immediately after sampling with liquid nitrogen and treated with 4-methoxyphenol as an inhibitor. In the next step, the sample is dissolved in tetrahydrofuran and then n-pentane is added to precipitate the resulting at the time of sampling polymer. Then the liquid phase (supernatant) investigated by gas chromatography, using a polar and a non-polar column for the determination of the monomers and a flame ionization detector is used. Typical parameters for the gas chromatographic determination are the following: 25 m silica capillary column with 5% phenyl, 1% vinyl methyl polysiloxane phase or 30 m silica capillary column with 50% phenyl 50% methyl polysiloxane phase, carrier gas hydrogen, split injector 150 ° C, oven temperature 50 to 180 ° C, flame ionization detector, detector temperature 275 ° C, internal standard isobutyl acrylate. The determination of the concentration of the monomers is carried out in the context of the present invention preferably by gas chromatography, in particular while maintaining the above-mentioned parameters.

The proportion of free monomers can be controlled in different ways. One way to keep the proportion of free monomers low is to choose the dosing of the mixture of olefinically unsaturated monomers to the actual reaction solution in which the monomers come into contact with the initiator, very low. If the metered addition rate is so low that all monomers can react almost instantly when in the reaction solution, it can be ensured that the proportion of free monomers is minimized. In addition to the metering rate, it is important that always sufficient radicals are present in the reaction solution, so that the metered monomers can be brought as soon as possible to the reaction. In this way, a further chain growth of the polymer is guaranteed and the proportion of free monomer is kept low. For this purpose, the reaction conditions are preferably to be selected so that the initiator feed is started even before the beginning of the metering of the olefinically unsaturated monomers. Preferably, the dosage is started at least 5 minutes before, more preferably at least 10 minutes before. Preferably, at least 10% by weight of the initiator, particularly preferably at least 20% by weight, very preferably at least 30% by weight of the initiator, in each case based on the total amount of initiator, is added before starting the metering of the olefinically unsaturated monomers. It is preferable to choose a temperature which allows a constant decomposition of the initiator. The amount of initiator is also an important factor for the sufficient presence of radicals in the reaction solution. The amount of initiator is to be chosen so that at any time sufficient radicals are available so that the added monomers can react. If the amount of initiator is increased, even larger amounts of monomers can be reacted at the same time.

Another factor that determines the rate of reaction is the reactivity of the monomers. Thus, the control of the proportion of free monomers can be controlled by the interaction of amount of initiator, rate of initiator addition, rate of monomer addition, and choice of monomers. Both the slowing of the dosage, as well as the increase in the amount of initiator, as well as the early start with the addition of the initiator serve the goal of keeping the concentration of the free monomers below the limits mentioned above. At any point in the reaction, the concentration of the free monomers can be determined by gas chromatography as described above. Should this analysis determine a concentration of free monomers approaching the limit of starvation polymerization, for example due to low levels of highly reactive olefinically unsaturated monomers, the above parameters may be used to control the reaction. In this case, for example, the metering rate of the monomers can be reduced or the amount of initiator can be increased.

In the context of the present invention, it is preferred that at least the polymerization stages ii. and iii. be carried out under starving conditions. This has the advantage of effectively minimizing the formation of new particulate matter in these two stages of polymerization. Instead, it succeeds, after stage i. existing particles (henceforth also referred to as seed) in stage ii. by the polymerization of Momomermischung B continue to grow (henceforth also called core). Likewise, it succeeds after stage ii. existing particles (hereinafter also called polymer comprising seed and core) in stage iii. by the polymerization of the monomer mixture C (henceforth also called shell), so that finally a polymer (b) comprising particles containing seed, core and shell results (also referred to as SCS polymer). Of course, the level i. be carried out under starving conditions. The mixtures (A), (B) and (C) are mixtures of olefinically unsaturated monomers. Suitable olefinically unsaturated monomers may be mono- or poly-olefinically unsaturated. In the following, suitable and, if appropriate, preferred monomers which are generally usable and are suitable for all mixtures (A), (B) and (C) are described. Specific specific embodiments of the individual mixtures will be discussed below.

Examples of suitable monoolefinically unsaturated monomers include in particular (meth) acrylate-based monoolefinically unsaturated monomers, allyl-containing monoolefinically unsaturated monomers and further vinyl-group-containing monoolefinically unsaturated monomers such as, for example, vinylaromatic monomers. The term (meth) acryl or (meth) acrylate in the context of the present invention comprises both methacrylates and acrylates. In any case, but not necessarily exclusively, (meth) acrylate-based monoolefinically unsaturated monomers are preferably used.

The (meth) acrylate-based, mono-olefinically unsaturated monomers may be, for example, (meth) acrylic acid and esters, nitriles or amides of (meth) acrylic acid. Preferred are esters of (meth) acrylic acid, with a radical R, which is not olefinically unsaturated.

respectively

The radical R may be saturated aliphatic, aromatic or mixed saturated aliphatic-aromatic. For the purposes of the present invention, aliphatic is understood as meaning all organic radicals which are not aromatic. The radical R is preferably aliphatic. The saturated aliphatic radical may be a pure hydrocarbon radical or it may contain heteroatoms of bridging groups (for example, oxygen from ether or ester groups) and / or with be functional groups containing heteroatoms (for example, alcohol groups) substituted. In the context of the present invention, therefore, a clear distinction is made between bridging groups containing heteroatoms and functional groups containing heteroatoms (ie terminal functional groups containing heteroatoms).

In any case, but not necessarily exclusively, monomers are used in which the saturated aliphatic radical R is a pure hydrocarbon radical (alkyl radical), ie contains no heteroatoms from bridging groups (for example oxygen from ether groups) and also not with functional groups (for example alcohol groups ) is substituted. In the event that R is an alkyl radical, it may be, for example, a linear, branched or cyclic alkyl radical. Of course, such an alkyl radical may also have linear and cyclic or branched and cyclic structural components. The alkyl radical preferably has 1 to 20, particularly preferably 1 to 10, carbon atoms.

Particularly preferred monounsaturated esters of (meth) acrylic acid with an alkyl radical are methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, amyl (meth) acrylate, hexyl (meth) acrylate, ethylhexyl (meth) acrylate, 3,3,5-trimethylhexyl (meth) acrylate, stearyl (meth) acrylate, lauryl (meth) acrylate, cycloalkyl (meth) acrylates, such as cyclopentyl (meth) acrylate, isobornyl (meth) acrylate and cyclohexyl (meth) acrylate wherein n- and tert-butyl (meth) acrylate and methyl methacrylate are very particularly preferred.

Further suitable radicals R are, for example, saturated aliphatic radicals which comprise functional groups containing heteroatoms (for example alcohol groups or phosphoric acid ester groups). Suitable monounsaturated esters of (meth) acrylic acid with a saturated aliphatic radical substituted by one or more hydroxyl groups are 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate,

Hydroxybutyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate, with 2-hydroxyethyl (meth) acrylate being most preferred. Suitable easy Unsaturated esters of (meth) acrylic acid with phosphoric acid ester groups are, for example, phosphoric acid esters of polypropylene glycol monomethacrylate, such as the commercially available Sipomer PAM 200 from Rhodia. Possible further vinyl group-containing monoolefinically unsaturated monomers are monomers other than the above-described acrylate-based monomers with a radical R 'on the vinyl group which is not olefinically unsaturated:

The radical R 'can be saturated-aliphatic, aromatic or mixed-saturated aliphatic-aromatic, aromatic and mixed saturated-aliphatic-a-aromatic radicals in which the aliphatic portions are alkyl groups, are preferred.

Particularly preferred further vinyl-containing monoolefinically unsaturated monomers are in particular vinyltoluene, alpha-methylstyrene and in particular styrene.

Also possible are vinyl group-containing monounsaturated monomers in which the radical R 'has the following structure:

where the radicals R 1 and R 2 are alkyl radicals which, in each case or together, contain a total of 7 carbon atoms. Such monomers are commercially available under the name VeoVa® 10 from Momentive.

Further fundamentally suitable monomers are olefinically unsaturated monomers such as acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, N-dimethylacrylamide, vinyl acetate, vinyl propionate, vinyl chloride, N-vinylpyrrolidone, N-vinylcaprolactam, N- Vinylformamide, N-vinylimidazole, N-vinyl-2-methylimidazoline and other unsaturated alpha-beta-carboxylic acids.

Examples of suitable multiply olefinically unsaturated monomers include esters of (meth) acrylic acid with an olefinically unsaturated radical R ". The radical R" may be, for example, an allyl radical or a (meth) acrylic acid radical:

respectively

Preferred poly olefinically unsaturated monomers include ethylene glycol di (meth) acrylate, 1,2-propylene glycol di (meth) acrylate, 2,2-

Propylene glycol di (meth) acrylate, butanediol, 4-di (meth) acrylate, neopentyl glycol di (meth) acrylate, 3-methylpentanediol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, Dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, hexanediol di (meth) acrylate and allyl (meth) acrylate.

In addition, preferred poly olefinic unsaturated compounds include acrylic and methacrylic acid esters of alcohols having more than two OH groups, such as trimethylolpropane tri (meth) acrylate or glycerol tri (meth) acrylate, but also trimethylolpropane di (meth) acrylate monoallyl ether, trimethylolpropane (meth) acrylate diallyl ether, pentaerythritol tri (meth) acrylate monoallyl ether, pentaerythritol di (meth) acrylate diallyl ether, pentaerythritol (meth) acrylate triallyl ether, triallyl sucrose, and pentaallylsucrose. Also possible are allyl ethers of mono- or polyhydric alcohols, such as, for example, trimethylolpropane monoallyl ether. If used, hexanediol diacrylate and / or allyl (meth) acrylate are preferred as the polyunsaturated monomers.

With regard to the monomer mixtures (A), (B) and (C) used in the individual polymerization stages are preferably special, in the sequence comply with the conditions set out above. First, it should be noted that the mixtures (A), (B) and (C) are in any case different from each other. They thus each contain different monomers and / or different proportions of at least one particular monomer.

Mixture (A)

The mixture (A) contains at least 50 wt .-%, preferably at least 55 wt .-%, of olefinically unsaturated monomers having a water solubility of less than 0.5 g / l at 25 ° C. A corresponding preferred monomer is styrene. The solubility of the monomers in water is determined by the method described below.

The monomer mixture (A) preferably contains no hydroxy-functional monomers. Also preferably, the monomer mixture (A) contains no acid-functional monomers. Most preferably, the monomer mixture (A) contains no monomers having functional groups containing heteroatoms. This means that heteroatoms, if present, are present only in the form of bridging groups. This is the case, for example, in the above-described (meth) acrylate-based, mono-olefinically unsaturated monomers which, as radical R, have an alkyl radical.

The monomer mixture (A) preferably contains only monoolefinically unsaturated monomers.

Preferably, the monomer mixture (A) contains at least one monounsaturated ester of (meth) acrylic acid having an alkyl group and at least one vinyl group-containing mono-olefinically unsaturated monomer having a vinyl group-attached group which is aromatic or which is mixed-saturated aliphatic-aromatic in which case the aliphatic moieties of the residue are alkyl groups.

The monomers contained in the mixture (A) are selected so that a polymer prepared therefrom has a glass transition temperature of 10 to 65 ° C, preferably from 30 to 50 ° C has. The glass transition temperature can be determined by the method described below.

That in stage i. Polymer prepared by the emulsion polymerization of the monomer mixture (A) is also referred to as seed. The seed preferably has an average particle size of 20 to 125 nm (measured by dynamic light scattering as described below;

Mixture (B)

The mixture (B) contains at least one poly olefinically unsaturated monomer, preferably at least one double olefinically unsaturated monomer. A corresponding preferred monomer is hexanediol diacrylate. The monomer mixture (B) preferably contains no hydroxy-functional monomers. Also preferably, the monomer mixture (B) contains no acid-functional monomers. Most preferably, the monomer mixture (B) contains no monomers having functional groups containing heteroatoms. This means that heteroatoms, if present, are present only in the form of bridging groups. This is the case, for example, in the above-described (meth) acrylate-based, mono-olefinically unsaturated monomers which, as radical R, have an alkyl radical.

Preferably, the monomer mixture (B) in addition to the at least one multi-olefinically unsaturated monomer, in any case, the following monomers: On the one hand at least one monounsaturated ester of (meth) acrylic acid with an alkyl radical and on the other hand, at least one vinyl group-containing mono-olefinically unsaturated monomer having a the radical group which is aromatic or which is mixed saturated aliphatic-aromatic, in which case the aliphatic moieties of the radical are alkyl groups.

The proportion of polyunsaturated monomers is preferably from 0.05 to 3 mol .-%, based on the total molar amount of monomers of the monomer mixture (B). The monomers contained in the mixture (B) are selected so that a polymer prepared therefrom has a glass transition temperature of -35 to 15 ° C, preferably -25 to + 7 ° C. The glass transition temperature can be determined by the method described below.

That in stage ii. The polymer prepared by the emulsion polymerization of the monomer mixture (B) in the presence of the seed is also referred to as the core. After stage ii. So results in a polymer comprising seed and core. The polymer which after stage ii. preferably has an average particle size of 80 to 280 nm, preferably 120 to 250 nm (measured by dynamic light scattering as described below;

Mixture (c)

The monomers contained in the mixture (C) are selected so that a polymer prepared therefrom has a glass transition temperature of -50 to 15 ° C, preferably -20 to + 12 ° C. The glass transition temperature can be determined by the method described below.

The olefinically unsaturated monomers of the mixture (C) are preferably selected so that the resulting polymer, comprising seed, core and shell, an acid number of 10 to 25 has. Accordingly, the mixture (C) preferably contains at least one alpha-beta unsaturated carboxylic acid, more preferably (meth) acrylic acid. The olefinically unsaturated monomers of mixture (C) are additionally or alternatively preferably selected so that the resulting polymer, comprising seed, core and shell, has an OH number of 0 to 30, preferably 10 to 25. All of the abovementioned acid numbers and OH numbers are values calculated on the basis of the total monomer mixtures used.

Preferably, the monomer mixture (C) contains at least one alpha-beta unsaturated carboxylic acid and at least one monounsaturated ester of (meth) acrylic acid having an alkyl group substituted with a hydroxyl group. The monomer mixture (C) particularly preferably contains at least one alpha-beta unsaturated carboxylic acid, at least one monounsaturated ester of (meth) acrylic acid having an alkyl group substituted with a hydroxyl group and at least one monounsaturated ester of (meth) acrylic acid having an alkyl group. If, in the context of the present invention, an alkyl radical is mentioned without any further specification, this always means a pure alkyl radical without functional groups and heteroatoms.

That in stage iii. Polymer prepared by the emulsion polymerization of the monomer mixture (C) in the presence of seed and core is also referred to as a shell. After stage iii. Thus, a polymer which comprises seed, core and shell, ie polymer (b), results. After its preparation, the polymer (b) has an average particle size of from 100 to 500 nm, preferably from 125 to 400 nm, very particularly preferably from 130 to 300 nm (measured by dynamic light scattering as described below;

The proportions of the mixture (A) is from 0.1 to 10% by weight, the proportion of the mixture (B) from 60 to 80% by weight and the proportion of the mixture ( C) from 10 to 30 wt .-%, each based on the sum of the individual amounts of the mixtures (A), (B) and (C).

As already stated above, the polymer (b) is preferably used in the form of an aqueous dispersion for the preparation of the pigment paste according to the invention. This aqueous dispersion preferably has a pH of 5.0 to 9.0, more preferably 7.0 to 8.5, most preferably 7.5 to 8.5. The pH can be kept constant even during the preparation, for example by the use of bases as mentioned below, or can also be adjusted specifically after the preparation of the polymer. In very particularly preferred embodiments, this aqueous dispersion has a pH of 5.0 to 9.0 and the at least one polymer (b) contained therein has a particle size of 100 to 500 nm. More preferred range combinations are: pH of 7.0 to 8.5 and a particle size of 125 to 400 nm, more preferably pH of 7.5 to 8.5 and a particle size of 130 to 300 nm. Preferably, the stages described i. to iii. without the addition of acids or bases known for adjusting the pH. Be used in the preparation of the polymer (b) then, for example, carboxy-functional monomers, which in the context of stage iii. is preferred, then the pH of the dispersion after completion of stage iii. are at less than 7. Accordingly, then, addition of base may be necessary to adjust the pH to a higher value, such as a value in the preferred ranges. From the above, it follows that the pH in this case is preferably after the stage iii. is set or must be adjusted accordingly, in particular by adding a base such as an organic, nitrogen-containing base such as ammonia, ammonia, trimethylamine, triethylamine, tributylamines, dimethylaniline, triphenylamine, N, N-dimethylethanolamine, methyldiethanolamine or triethanolamine, and by addition of sodium bicarbonate or borates and also mixtures of the aforementioned substances. However, this does not exclude that the pH value can also be adjusted before, during or after the emulsion polymerizations or between the individual emulsion polymerizations. It is also possible that the choice of the monomers, the adjustment of the pH to a desired value is not necessary. In this case, the measurement of the pH is preferably carried out with a pH meter (for example Mettler-Toledo S20 SevenEasy pH meter) with a combined pH electrode (for example Mettler-Toledo InLab® routine).

If the polymer (b) is used in the form of an aqueous dispersion for the preparation of the pigment paste of the invention, the nonvolatile fraction is preferably in the range from 5 to 40% by weight, particularly preferably in the range from 20 to 30% by weight. in each case based on the total weight of the aqueous dispersion. The non-volatile content is determined according to the method described below. Preferably, the aqueous dispersion used contains from 55 to 75 wt .-%, particularly preferably from 60 to 70 wt .-%, each based on the total weight of the dispersion, water. It is preferred that the percentage sum of the solids of the dispersion and the proportion of water in the dispersion at least 80 wt .-%, preferably at at least 90% by weight. Preferred among these are ranges from 80 to 99% by weight, in particular from 90 to 97.5% by weight. Accordingly, the aqueous dispersion used largely consists of water and the polymer (b) and contains polluting components such as organic solvents in particular or only in small proportions.

Further optional components of the pigment paste according to the invention

The pigment paste of the invention may contain further optional constituents or optional components:

In addition to the at least one color pigment (a), the pigment paste may additionally contain at least one effect pigment which is different from the color pigment (a).

A person skilled in the art is familiar with the term effect pigments. A corresponding definition can be found, for example, in Römpp Lexikon, Lacke and Druckfarben, Georg Thieme Verlag, 998, 10th edition, pages 176 and 471. Preferably, the effect pigments are pigments which have an optically effecting or color and optically effecting effect, in particular optically effecting, are. The terms "optically effecting and coloring pigment", "optically effecting pigment" and "effect pigment" are therefore preferably 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, pearlescent 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. Platelet-shaped effect pigments, in particular platelet-shaped, are particularly preferred

Aluminum pigments and metal oxide-mica pigments contained in the pigment paste. The proportion of effect pigments is preferably in the range from 1.0 to 50.0% by weight, preferably 2.0 to 45.0% by weight, particularly preferably 5.0 to 40.0% by weight, in each case based on on the total weight of the aqueous pigment paste. However, the pigment paste according to the invention preferably contains the at least one color pigment (a) as sole pigment, ie it preferably contains no additional pigments such as effect pigments. In addition, the pigment paste according to the invention preferably also contains no fillers.

The pigment paste 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 (eg, 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. Corresponding products are commercially available, for example, under the name Aquatix®. Preferably, the at least one thickener in the pigment paste according to the invention is present in an amount of at most 10% by weight, more preferably from at most 7.5% by weight, very particularly preferably at most 5% by weight, in particular at most 3% by weight, most preferably at most 2% by weight, in each case based on the total weight of the pigment paste.

Depending on the desired application, the pigment paste of the invention may contain one or more commonly used additives as further component (s). For example, as already explained above, the pigment paste may contain a certain amount of at least one organic solvent. Furthermore, the pigment paste at least one additive selected from the group consisting of reactive diluents, fillers, 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 the pigment paste of the invention is from 0.01 to 20.0 wt .-%, more preferably 0.05 to 15.0 wt .-%, particularly preferably 0.1 to 10.0 % By weight, most preferably from 0.1 to 7.5% by weight, especially from 0.1 to 5.0% by weight and most preferably from 0.1 to 2.5% by weight ,

The preparation of the pigment paste of the invention can be carried out using the customary for the production of pigment pastes mixing methods and mixing units.

Inventive basecoat

The pigment paste according to the invention is suitable for the production of an aqueous basecoat material. Another object of the present invention is therefore an aqueous basecoat, wherein the basecoat is prepared by admixing at least one pigment paste according to the invention as component (1) to at least one suitable for the preparation of a basecoat aqueous component (2) containing at least one usable as a binder polymer , wherein this polymer which can be used as a binder is the same as in the pigment paste contained polymer (b) and / or is at least one of them different polymer.

The proportions in% by weight of all components (1), (2) and water present in the basecoat material according to the invention and further components optionally present in addition add up to 100% by weight, based on the total weight of the basecoat material.

All of the preferred embodiments hereinbefore described in connection with the pigment paste according to the invention are also preferred embodiments with regard to the use of this pigment paste for producing the basecoat material according to the invention, in particular in connection with components (a) and (b) of the pigment paste.

The term of the basecoat is known in the art and defined for example in Rompp Lexikon, paints and printing inks, Georg Thieme Verlag, 998, 10th edition, page 57. Under a basecoat is therefore in particular used in the automotive finishing and general industrial coating coloring and / or to understand coloring and an optical effect giving intermediate coating material. This is generally applied to a pre-treated with filler or Grundierfüller metal or plastic substrate, sometimes even applied directly to the plastic substrate. Even old paints, which may still have to be pretreated (for example, by grinding), can serve as substrates. Meanwhile, it is quite common to apply more than one basecoat. Accordingly, in such a case, a first basecoat film is the background for a second. In order to protect a basecoat film in particular against environmental influences, at least one additional clearcoat film is applied to it.

The component (2) used to prepare the basecoat material according to the invention contains at least one polymer which can be used as a binder, this polymer suitable as a binder being the polymer (b) also present in the pigment paste and / or at least one polymer other than this. Preferably, it is in the usable as a binder and in component (2) contained polymers to the polymer also contained in the pigment paste (b).

The basecoat contains at least one polymer (b) by the use of the pigment paste according to the invention for its preparation. The at least one polymer (b) is preferably the main binder of the basecoat. As the main binder in the present invention, a binder component is preferably referred to when there is no other binder component in the coating agent such as the base paint, which is present in a higher proportion based on the total weight of the respective coating agent. The term binder has already been defined above with reference to DIN EN ISO 4618 (German version, date: March 2007).

The basecoat according to the invention is aqueous. It is preferably a system containing as solvent mainly water, preferably in an amount of at least 20 wt .-%, and organic solvents in minor proportions, preferably in an amount of <20 wt .-%, in each case based on the total weight of the basecoat according to the invention.

The basecoat material of the invention preferably contains at least 20% by weight, more preferably at least 25% by weight, very preferably at least 30% by weight, in particular at least 35% by weight, based in each case on water the total weight of the basecoat.

The basecoat material according to the invention preferably contains a proportion of water which ranges from 20 to 60% by weight, more preferably from 25 to 55% by weight, most preferably from 30 to 50% by weight. %, in each case based on the total weight of the basecoat.

The basecoat material according to the invention preferably contains a proportion of organic solvents which is in a range of <20% by weight, more preferably in a range of 0 to <20% by weight, most preferably in a range of 0.5 to <20% by weight or up to 15% by weight, in each case based on the total weight of the basecoat.

The solids content of the basecoat material of the invention is preferably in the range from 10 to 50% by weight, more preferably from 1 to 45% by weight, very preferably from 12 to 40% by weight, in particular from 13 to 37.5 % By weight, in each case based on the total weight of the basecoat. The determination of the solids content, ie the non-volatile content, is carried out according to the method described below.

The percentage sum of the solids of the basecoat of the invention and the proportion of water in the basecoat of the invention is preferably at least 40% by weight, preferably at least 50% by weight. Preferred among these are ranges from 40 to 95% by weight, in particular 45 or 50 to 90% by weight. Thus, for example, if a basecoat according to the invention has a solids content of 18% by weight and a water content of 25% by weight, the percentage sum of the solids and the proportion of water defined above is 43% by weight.

The basecoat material according to the invention preferably contains a proportion of polymer (b) in a range from 1.0 to 20% by weight, particularly preferably from 1.5 to 19% by weight, very particularly preferably from 2.0 to 18.0 Wt .-%, in particular from 2.5 to 17.5 wt .-%, most preferably from 3.0 to 15.0 wt .-%, each based on the total weight of the basecoat. The determination or determination of the proportion of the polymer (b) in the basecoat can be carried out by determining the solids content (also called nonvolatile content, solids content or solids content) of an aqueous dispersion comprising the polymer (b) which is used to prepare both the pigment paste ( Component 1) and optionally for the preparation of component (2) is used.

The basecoat material according to the invention preferably contains a proportion of color pigment (a) in a range from 1 to 25% by weight, particularly preferably from 1.5 to 22.5% by weight, very particularly preferably from 2 to 20% by weight. , in particular from 2.5 to 18 wt .-%, most preferably from 3 to 16 wt .-% or from 3 to 15 wt .-%, each based on the total weight of the basecoat.

Preferably, the relative weight ratio of the at least one color pigment (a) to the polymer (b) in the basecoat is in a range from 8: 1 to 1: 2, more preferably in a range from 6: 1 to 1: 1, most preferably in a range from 5: 1 to 1: 1, in particular in a range from 4: 1 to 1: 1.

The aqueous basecoat material according to the invention, for the preparation of which the pigment paste according to the invention is used, preferably comprises an aqueous dispersion of the polymer (b) which is introduced into the basecoat at least by admixing the pigment paste. The polymer (b) has already been described above. The aqueous basecoat according to the invention contains at least at least by the use of the pigment paste according to the invention in its production at least one color pigment, namely color pigment (a). Corresponding color pigments (a) have already been described above. In addition, the aqueous basecoat material according to the invention may contain further pigments other than the color pigment (a), in particular effect pigments. Corresponding pigments have likewise already been described above. Preferably, these pigments are contained in the component (2) which is used for the preparation of the basecoat. The total amount of all pigments in the basecoat is preferably in the range from 0.5 to 40.0% by weight, more preferably from 2.0 to 20.0% by weight, particularly preferably from 3.0 to 15.0% by weight. -%, in each case based on the total weight of the basecoat.

The novel aqueous basecoat preferably also contains at least one polymer other than the polymer (b) as binder, in particular at least one polymer selected from the group consisting of polyurethanes, polyureas, polyesters, poly (meth) acrylates and / or copolymers of said polymers, in particular Polyurethane-poly (meth) acrylates and / or polyurethane-polyureas. Preferably, this polymer other than the polymer (b) is contained in the component (2) used to prepare the base paint. It is possible that the component (2) no Polymer (b) contains, but instead at least one polymer selected from the group consisting of polyurethanes, polyureas, polyesters, poly (meth) acrylates and / or copolymers of said polymers, especially polyurethane poly (meth) acrylates and / or polyurethane polyureas ,

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 polyurethane-polyurea copolymers are polyurethane-polyurea particles, preferably those having an average particle size of from 40 to 2000 nm, the polyurethane-polyurea particles, in each case in reacted form, containing at least one isocyanate group-containing polyurethane prepolymer containing anionic and / or or groups which can be converted into anionic groups and at least one polyamine containing two 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. The average particle size of such polyurethane-polyurea particles is as follows determined (measured by dynamic light scattering as described below, see determination method 4).

The proportion of such polymer (b) of different polymers in the basecoat is preferably smaller than the proportion of the polymer (b) in the basecoat. The polymers described are preferably hydroxy-functional and more preferably have an OH number in the range from 15 to 200 mg KOH / g, more preferably from 20 to 150 mg KOH / g.

Particularly preferably, the basecoats contain at least one hydroxy-functional polyurethane-poly (meth) acrylate copolymer, more preferably at least one hydroxy-functional polyurethane-poly (meth) acrylate copolymer and at least one hydroxy-functional polyester and optionally a preferably hydroxy-functional polyurethane-polyurea copolymer.

The proportion of the further polymers as a binder can vary widely and is preferably in the range from 1.0 to 25.0% by weight, preferably 3.0 to 20.0% by weight, particularly preferably 5.0 to 15.0 Wt .-%, each based on the total weight of the basecoat.

In addition, the basecoat of the invention may contain at least one typical crosslinking agent known per se. If it contains a crosslinking agent, it is preferably at least one aminoplast resin and / or at least one blocked or free polyisocyanate, preferably an aminoplast resin. Among the aminoplast resins, melamine resins are particularly preferred. If the basecoat contains crosslinking agent, the proportion of these crosslinking agents, in particular aminoplast resins and / or blocked or free polyisocyanates, more preferably amino resins, including preferably melamine resins, preferably in the range of 0.5 to 20.0 wt .-%, preferably 1, 0 to 15.0 wt .-%, particularly preferably 1, 5 to 10.0 wt .-%, each based on the total weight of the basecoat. The proportion of crosslinking agent is preferably smaller than the proportion of the polymer (b) in the basecoat. Further optional components of the basecoat according to the invention

The basecoat according to the invention may contain further optional constituents or optional components. These are the same constituents mentioned above in connection with the pigment paste according to the invention, such as effect pigments, thickeners, organic solvents and the abovementioned further additives.

The proportion of effect pigments is preferably in the range from 0.5 to 30.0% by weight, preferably from 1.0 to 25.0% by weight, particularly preferably from 1.5 to 15.0% by weight, in each case based on on the total weight of the aqueous basecoat. The at least one thickener in the basecoat material according to the invention 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 the basecoat, before. The content of the at least one further additive, based on the total weight of the basecoat material according to the invention, is preferably 0.01 to 20.0% by weight, more preferably 0.05 to 15.0% by weight, particularly preferably 0, From 1 to 10.0% by weight, very particularly preferably from 0.1 to 7.5% by weight, in particular from 0.1 to 5.0% by weight and most preferably from 0.1 to 2, 5% by weight.

The preparation of the basecoat material of the invention can be carried out using the customary and known for the production of basecoats mixing methods and mixing units, but the pigment paste according to the invention as Zumischkomponente (component (1)) is used.

Use of the polymer (b) for dispersing color pigments within an aqueous effect pigment paste

The polymer (b) is suitable for dispersing color pigments within an aqueous color pigment paste. Another object of the present invention is therefore a use of the in connection with the first Subject of the present invention mentioned polymer (b) for the dispersion of color pigments within an aqueous color pigment paste.

All the preferred embodiments described above in connection with the pigment paste according to the invention and the basecoat according to the invention herein are also preferred embodiments with regard to the use of the polymer (b) for dispersing color pigments within an aqueous color pigment paste.

Multi-layer coating

Another object of the present invention is a process for producing a multi-layer coating (multi-layer coating), in which

(1a) an aqueous basecoat is applied to a substrate,

(2a) a polymer film is formed from the lacquer applied in step (1a),

(1 b) optionally on the polymer film thus formed a further aqueous

Basecoat is applied,

(3) a clearcoat is applied to the basecoat layer (s) so obtained, and then

(4) the basecoat film (s) together with the clearcoat film is / are cured together, which is characterized in that the basecoat material according to the invention in stage (1 a) or - if the process also comprises stages (1 b) and (2b) comprises - in step (1 a) and / or (1 b), preferably in step (1 b) is used. All of the abovementioned (preferred) statements with respect to the pigment paste according to the invention and the aqueous basecoat material according to the invention also apply to the process according to the invention. The process is used for the production of multicoat colorants and dyes and effects. The substrate used in step (1a) preferably has an electrocoating layer (ETL), particularly preferably an electrocoating layer applied by means of cathodic deposition of an electrodeposition paint, and the basecoat used in step (1a) is applied directly to the ETL-coated preferably metallic substrate applied, wherein the applied to the substrate Eiektrotauchlackschicht (ETL) in carrying out the step (1 a) is preferably already cured. In step (4), preferably the metallic substrate coated according to steps (1a) and (2a) on the preferably metallic substrate coated with a preferably cathodic cured electrocoating layer, then the basecoat layer applied according to steps (1b) and (2b) is further applied thereto Basecoat layer, and the in turn according to step (3) applied thereto clearcoat cured together.

The application of the aqueous basecoat of the invention is usually carried out on filler or Grundierfüller pretreated metal or plastic substrates. Optionally, said basecoat can also be applied directly to the plastic substrate. Alternatively, the aqueous basecoat material according to the invention can preferably also be carried out without prior coating of the substrate, in particular a metal substrate, with a filler or primer filler. In this case, the process according to the invention preferably comprises stages (1b) and (2b), i. at least two basecoat films are applied, the basecoat material according to the invention being used within stages (1a) and / or (1b), particularly preferably only within stage (1b). In this case, the metal substrate used is preferably coated with a cured Eikotrucklackschicht.

If a metal substrate is to be coated, then it is preferably coated with an electrodeposition coating before the filler or primer filler or the aqueous basecoat material according to the invention is applied. If a plastic substrate is coated, it is preferably pretreated before the application of the filler or primer filler or of the aqueous basecoat material according to the invention. The most commonly used methods are flaming, plasma treatment and corona discharge. Preferably, the flaming is used. The application of the aqueous or the inventive Basecoats or basecoats on a metal substrate can take place in the layer thicknesses customary within the framework of the automobile industry in the range of, for example, 5 to 100 micrometers, preferably 5 to 60 micrometers, particularly preferably 5 to 30 micrometers. In this case, spray application methods are used, such as compressed air spraying, airless spraying, high rotation, electrostatic spray application (ESTA), optionally combined with hot spray application such as hot air hot spraying.

After the application of the aqueous basecoat or the aqueous basecoats, this or these can be dried by known methods. For example, (I-component) basecoats, which are preferred, may be flashed off at room temperature (23 ° C) for 1 to 60 minutes, and subsequently preferably dried at optionally slightly elevated temperatures of 30 to 90 ° C. In the context of the present invention, flash drying and drying is understood to mean evaporation of organic solvents and / or water, as a result of which the paint is drier but not yet cured, or a completely crosslinked paint film is not yet formed.

Then, a commercial clearcoat is also applied according to common methods, wherein the layer thicknesses are again in the usual ranges, for example 5 to 100 micrometers.

After application of the clearcoat this can be flashed off at room temperature (23 ° C) for example, 1 to 60 minutes and optionally dried. Then the clearcoat is cured together with the applied basecoat. Crosslinking reactions take place, for example, as a result of which an effect-imparting and / or coloring and effect-imparting multi-layer coating according to the invention is produced on a substrate. The curing is preferably carried out thermally at temperatures of 60 to 200 ° C. The coating of plastic substrates is basically analogous to that of metal substrates. However, it is generally cured at much lower temperatures of 30 to 90 ° C here. Preference is therefore given to the use of two-component clearcoats. With the aid of the method according to the invention, it is possible to coat metallic and non-metallic substrates, in particular plastic substrates, preferably automobile bodies or parts thereof. The process according to the invention can also be used for double-coating in OEM coating. This is to be understood as meaning that a substrate which has been coated with the aid of the method according to the invention is lacquered a second time, likewise with the aid of the method according to the invention.

The said substrate from step (1a) may also be a multicoat paint system which has defects. In this multi-layer substrate coating, which has defects, so it is an original finish, which is to be repaired or completely overpainted. The inventive method is therefore suitable for repairing defects on multi-layer coatings. Defects or film defects are generally termed disturbances on and in the coating, which are usually named according to their shape or appearance. A variety of possible types of such film defects are known to those skilled in the art. These are described, for example, in Rompp-Lexikon Lacke und Druckfarben, Georg Thieme Verlag, Stuttgart, New York, 1998, page 235, "film defects".

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 125 ° 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 the solubility of the monomers of the mixture (A) in water used for the preparation of the polymer (b)

The solubility of the monomers in water is determined by equilibrium with the gas space above the aqueous phase (analogous to the literature X.- S. Chai, QX Hou, FJ Schork, Journal of Applied Polymer Science Vol. 99, 1296-1301 (2006) ). For this purpose, in a 20 ml Gasraumprobenröhrchen given to a defined volume of water such as 2 ml such a large mass of the respective monomer that this mass can not solve completely in any case in the selected volume of water. In addition, an emulsifier (10 ppm, based on the total mass of the sample mixture) is added. In order to maintain the equilibrium concentration, the mixture is shaken constantly. The supernatant gas phase is exchanged for inert gas, so that sets an equilibrium again. In each case the proportion of the substance to be detected is measured in the withdrawn gas phase (for example by means of gas chromatography). The equilibrium concentration in water can be determined by graphically evaluating the proportion of monomer in the gas phase. The slope of the curve changes from a nearly constant value (S1) to a significantly negative slope (S2) as soon as the excess monomer content has been removed from the mixture. The equilibrium concentration is reached at the intersection of the straight line with the slope S1 and the straight line with the slope S2. The described determination is carried out at 25 ° C. 3. Determination of the glass transition temperatures of polymers obtainable in each case from monomers of the mixtures (A), (B) or (C)

The glass transition temperature T _g is determined experimentally on the basis of DIN 51005 (Date: August 2005) "Thermal Analysis (TA) - Terms" and DIN 53765 (Date: March 1994) "Thermal Analysis - Differential Scanning Calorimetry (DDK)". A sample of 15 mg is weighed into a sample pan and introduced into a DSC instrument. It is cooled to the starting temperature and then a 1. and a second measuring run with an inert gas purging (N ₂ ) of 50 ml / min at a heating rate of 10 K / min, being cooled between the measuring runs back to the starting temperature. The measurement is made in the temperature range of about 50 ° C lower than the expected glass transition temperature to about 50 ° C higher than the expected glass transition temperature. The glass transition temperature referred to DIN 53765, point 8.1, the temperature in the second run, in which half of the change in the specific heat capacity (0.5 delta cp) is reached. It is determined from the DDK diagram (order of heat flow against temperature). It is the temperature that corresponds to the intersection of the centerline between the extrapolated baselines before and after the glass transition with the trace. For a purposeful estimation of the glass transition temperature expected during the measurement, the known Fox equation can be used. Since the Fox equation is a good approximation, based on the glass transition temperatures of the homopolymers and their parts by weight without including the molecular weight, it can be used as a useful tool for those skilled in the synthesis, so that a desired glass transition temperature can be adjusted via a few targeted experiments ,

4. Determination of the average particle size of the polymer (b) and the optionally usable polyurethane-polyurea particles

The mean particle size is determined by means of dynamic light scattering (photon correlation spectroscopy) (PCS) in accordance with DIN ISO 3321 (date: October 2004). By average particle size is meant the measured mean particle diameter (Z-average mean). For the measurement, a "Malvern Nano S90" (Malvem Instruments) is used at 25 ± 1 ° C. The device covers a size range of 3 to 3000 nm and is equipped with a 4mW He-Ne laser at 633 nm. The respective samples are diluted with particle-free, deionized water as dispersing medium and then measured in a 1 ml polystyrene cuvette with suitable scattering intensity , The evaluation was carried out by means of a digital correlator with the aid of the evaluation software Zetasizer Ver. 7.1.1 (Malvern Instruments). It is measured five times and the measurements are repeated on a second, freshly prepared sample. With regard to the polymer (b), the average particle size is understood to mean the arithmetic number average of the measured mean particle diameter (Z average). The standard deviation of a 5-fold determination is <4%. With regard to the optionally usable polyurethane-polyurea particles, the average particle size is understood to mean the arithmetic volume average of the average particle size of the individual preparations (V average). The maximum deviation of the volume average of five individual measurements is ± 15%. The verification is carried out with polystyrene standards with certified particle sizes between 50 to 3000 nm.

5. Determination of the number average molecular weight

The number average molecular weight (M _n ), unless otherwise stated, by means of a steam pressure osmometer type 10.00 (Knauer) in concentration series in toluene at 50 ° C with benzophenone as a calibration substance for determining the experimental calibration constant of the measuring device used by E. Schröder, G. Müller, K.-F. Arndt, "Guidelines of Polymer Characterization", Akademie-Verlag, Berlin, pp. 47-54, 1982.

6. Determination of the layer thicknesses

The layer thicknesses are determined in accordance with DIN EN ISO 2808 (date: May 2007), method 12A using the measuring instrument MiniTest® 3100-4100 from ElektroPhysik.

7. Determination of storage stability

To determine the storage stability, the samples to be tested before and after storage at 40 ° C for 2 weeks with a DIN 53019-1 (Date: September 2008) and according to DIN 53019-2 (Date: February 2001) calibrated rotational viscometer under tempered conditions (23.0 ° C ± 0.2 ° C). The samples are sheared s first for 5 minutes at a shear rate of 1000 ^"1 (loading phase) and then 8 minutes at a shear rate of 1 ^s" (discharge phase). The mean viscosity level during the stress phase (high shear viscosity) and the level after 8 minutes of relief (low shear viscosity) are determined from the measured data and the values before and after storage are compared by calculating the respective percentage changes.

8. Assessment of the occurrence of pinholes and the layer-thickness-dependent course

8.1 In order to assess the occurrence of pinholes and the layer thickness-dependent course, wedge-shaped multicoat paint systems are produced according to the following general rules (variants A to C):

Variant A: water-based paint as a wedge

A 30 x 50 cm steel sheet coated with a standard cathodic electrocoat (CathoGuard® 800 from BASF Coatings GmbH) is provided on one longitudinal edge with an adhesive strip (Tesaband, 19 mm) in order to be able to determine layer thickness differences after the coating. A water-based bag is applied electrostatically as a wedge with a target layer thickness (layer thickness of the dried material) of 0-40 pm. After a flash-off time of 4-5 minutes at room temperature (23 ° C), the assembly is dried in a convection oven for 10 minutes at 60 ° C. After removal of the adhesive strip, a commercially available two-component clearcoat (ProGloss® from BASF Coatings GmbH) with a target layer thickness (layer thickness of the dried material) of 40-45 μm is applied manually to the dried aqueous basecoat by means of a flow cup gun. The resulting clearcoat is flashed for 10 minutes at room temperature (23 ° C). This is followed by curing in a circulating air oven at 140 ° C. for a further 20 minutes. Variant B: First water-based paint as a wedge, second water-based paint as a constant coat

A 30 x 50 cm steel sheet coated with a standard cathodic electrocoat (CathoGuard® 800 from BASF Coatings) is provided on one longitudinal edge with two adhesive strips (Tesaband, 19 mm) in order to be able to determine layer thickness differences after the coating. A first water-based bag is applied electrostatically as a wedge with a target layer thickness (layer thickness of the dried material) of 0-30 pm. This is followed by a venting for 3 minutes at room temperature (23 ° C), before removing one of the two adhesive strips, a second aqueous base coat is also applied electrostatically in a single-use. The target layer thickness (layer thickness of the dried material) is 13-16 pm. After renewed flash off for 4 minutes at room temperature (23 ° C), the assembly is dried in a convection oven for 10 minutes at 60 ° C. After removal of the second adhesive strip, a commercially available two-component clearcoat material (ProGloss® from BASF Coatings GmbH) with a target layer thickness (layer thickness of the dried material) of 40-45 μm is applied manually to the dried aqueous basecoat materials by means of a flow cup gun. The resulting clearcoat is flashed for 10 minutes at room temperature (23 ° C). This is followed by curing in a circulating air oven at 140 ° C. for a further 20 minutes.

Variant C: First water-based paint as a constant coat, second water-based paint as a wedge

A 30 x 50 cm steel sheet coated with a standard KTL (CathoGuard® 800 from BASF Coatings) is provided on one longitudinal edge with two adhesive strips (Tesaband, 9 mm) in order to be able to determine layer thickness differences after the coating. A first water-based can is applied electrostatically with a target layer thickness (layer thickness of the dried material) of 18-22 pm. This is followed by a venting for 3 minutes at room temperature (23 ° C), after the removal of one of the two strips of the second water-based paint is also applied electrostatically in a single order as a wedge. The target layer thickness (layer thickness of the dried material) is 0-30 pm. After renewed flash off for 4 minutes at room temperature (23 ° C), the assembly is dried in a convection oven for 10 minutes at 60 ° C. After removal of the second adhesive strip, a commercially available two-component clearcoat (ProGloss® from BASF Coatings GmbH) with a target layer thickness (layer thickness of the dried material) of 40-45 μm is applied manually to the dried aqueous basecoat films by means of a flow cup gun. The resulting clearcoat is flashed for 10 minutes at room temperature (23 ° C). This is followed by curing in a circulating air oven at 140 ° C. for a further 20 minutes.

8.2 Assessment of the occurrence of pinholes

To assess the occurrence of pinholes, multicoat paint systems are prepared in accordance with the methods for painting water-based paint wedge assemblies (variants B or C) mentioned in section 8.1 and then assessed visually according to the following general specification:

The dry film thickness of the entire waterborne basecoat, consisting of the first and second waterborne basecoats, is controlled and for the basecoat film thickness wedge the areas of 0-20 pm and 20 pm to the end of the wedge are marked on the steel panel. The evaluation of the pinholes is done visually in the two separate areas of the waterborne paint wedge. For each area, the number of pinholes is counted. All results are normalized to an area of 200 cm ² . In addition, if necessary, it is recorded from which dry layer thickness of the waterborne base wedge no more needle sticks occur.

8.3 Assessment of the layer thickness-dependent course

To assess the layer thickness-dependent course, multicoat paint systems are prepared in accordance with the methods for painting water-based paint wedge assemblies (variants A, B or C) and then evaluated according to the following general specification:

The dry film thickness of the entire aqueous basecoat composition, consisting of the first and the second aqueous basecoat material, is controlled and for the basecoat film thickness wedge at least one of the ranges of 15-20 μm and 20-25 μm or 10-15 μm, 15-15 μm, respectively. 20 pm, 20-25 pm, 25-30 pm and optionally 30-35 pm marked on the steel sheet. The determination or evaluation of the layer thickness-dependent course is carried out with the help of the measuring device Wave scan by Byk / Gardner within the four previously determined basecoat layer thickness ranges. For this purpose, a laser beam is directed onto the surface to be examined at an angle of 60 °, and the fluctuations in the reflected light in a so-called short wave range (0.3 to 1.2 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 multi-layer structure, the characteristic "distinctness of imgage" (DOI) is determined with the aid of the measuring device (the higher the value, the better the appearance).

9. Assessment of the occurrence of cookers and runners

To determine the boiling and run tendency of a sample, multicoat paint systems according to DIN EN ISO 28199-1 (date: January 2010) and DIN EN ISO 28199-3 (date: January 2010) are produced according to the following general specification:

A perforated plate of dimensions 57 cm x 20 cm made of steel coated with a standard cathodic electrocoat (CathoGuard® 800 from BASF Coatings GmbH) (in accordance with DIN EN ISO 28199-1, point 8.1, version A) is analogous to DIN EN ISO 28199-1 , Section 8.2 (version A) prepared. Subsequently, in accordance with DIN EN ISO 28199-1, point 8.3, the application of a basecoat composition is carried out electrostatically in a single application as a wedge with a target layer thickness (layer thickness of the dried material) in the range from 0 μm to 40 μm. The resulting aqueous basecoat is dried after a flash off at 18-23 ° C for 10 minutes (runner test) or without previous flash-off in a convection oven for 5 minutes at 80 ° C. In the case of testing for runners, the sheets are thereby vertically suspended and dried. The determination of the cooker limit, ie the basecoat film thickness above which the digester occurs, is carried out in accordance with DIN EN ISO 28199-3, item 5. The determination of the tendency to run is carried out in accordance with DIN EN ISO 28199-3, item 4. In addition to the layer thickness at which a runner's length exceeds 10 mm from the lower edge of the hole, that layer thickness is determined from which a first tendency to run on a hole is visually observed.

10. Assessment of the appearance of pigment agglomerates

To evaluate the appearance of pigment agglomerates as a result of insufficient stabilization of the pigments in the paste employed, a suitable sample, such as water-based paint, is tested according to the following general rules: a) Coating a glass sheet

The corresponding waterborne basecoat is applied by means of a 150 μm box doctor blade on a 9 x 15 cm glass plate. When wet and after a 60 minute flash off at room temperature (23 ° C), the film is visually assessed for speckling by holding it against a source of light so as not to misinterpret any air bubbles as specks. It is given a grade of 1 -5 (1 = no specks / 5 = very many specks) or it is judged in relation to a reference (reference = 0, ++ = much better, + = better, - = worse, - = significantly worse). b) coating a steel sheet

On a coated with a primer coat steel sheet of dimensions 32 x 60 cm, the water-based paint to be examined is applied by means of two-coat; the application in the first step is electrostatic with a target layer thickness of 8-9 pm, in the second step, after a 2-minute flash off at room temperature (23 ° C) pneumatically applied with a target layer thickness of 4-5 pm. The resulting aqueous basecoat film is then dried after renewed flash off at room temperature (23 ° C) of 5 minutes in a convection oven for 5 minutes at 80 ° C. A commercially available two-component clearcoat (ProGloss® from BASF Coatings GmbH) having a target layer thickness of 40-45 μm is applied to the dried aqueous basecoat. The resulting clearcoat is flashed for 10 minutes at room temperature (23 ° C). This is followed by curing in a circulating air oven at 140 ° C. for a further 20 minutes. The evaluation of specks is done visually; a grade of 1 -5 is awarded (1 = no specks / 5 = very many specks). 11. Visual assessment for segregation

The sample to be tested, such as a pigment paste or water-based paint, is visually assessed for stability by storing the mixture in a sealed glass jar at room temperature (23 ° C) and / or at 40 ° C for a period of at least four weeks. It is then checked visually whether a separation has taken place or whether the material has changed in terms of its homogeneity. It is given a grade of 1 -5 (1 = very stable, no segregation or no formation of multiple phases / 5 = very unstable, strong demixing or very distinct formation of several phases).

12. Determination of hiding power

The hiding power is determined in accordance with DIN EN ISO 28199-3 (January 2010, point 7).

13. Determination of the OH number and the acid number

The determination of the OH number and the acid number is carried out by calculation.

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 an Aqueous Dispersion AD1

1.1 The components mentioned below and used to prepare the aqueous dispersion AD1 have the following meanings:

DMEA dimethylethanolamine

Deionised water

EF 800 Aerosol® EF-800, commercially available emulsifier of the

Company Cytec

APS ammonium peroxodisulfate

1, 6-HDDA 1, 6-hexanediol diacrylate

2-HEA 2-hydroxyethyl acrylate

MMA methyl methacrylate

1.2 Preparation of the aqueous dispersion AD1 comprising a multistage SCS polyacrylate

Monomer mixture (A), stage i.

80 wt .-% of the positions 1 and 2 according to the following Table 1 .1 are placed in a steel reactor (5 L volume) with reflux condenser and heated to 80 ° C. The remaining portions of the components listed under "template" in Table 1.1 are premixed in a separate vessel, and this mixture and separately the initiator solution (Table 1 .1, positions 5 and 6) are added dropwise at the same time within 20 min in the reactor in the reaction solution, a proportion of the monomers, based on the total amount of used in stage i Monomers, of 6.0 wt .-% during the entire reaction time is not exceeded. The mixture is then stirred for 30 minutes.

Monomer mixture (B), stage iL

The components listed under "Mono" in Table 1.1 are premixed in a separate vessel. This mixture is added dropwise within 2 hours in the reactor, wherein in the reaction solution, a proportion of the monomers, based on the total amount in stage ii. used monomers, of 6.0 wt .-% during the entire reaction time is not exceeded. The mixture is then stirred for 1 hour.

Monomer mixture (C), stage iii.

The components indicated in Table 1 .1 under "Mono 2" are premixed in a separate vessel, and this mixture is added dropwise to the reactor within 1 hour, in the reaction solution a proportion of the monomers, based on the total amount of in stage iii of 6.0% by weight is not exceeded during the entire reaction time, followed by stirring for 2 hours.

Thereafter, the reaction mixture is cooled to 60 ° C and the neutralization mixture (Table 1.1, positions 20, 21 and 22) premixed in a separate vessel. The neutralization mixture is added dropwise to the reactor within 40 minutes, the pH of the reaction solution being adjusted to a pH of 7.5 to 8.5. Subsequently, the reaction product is stirred for a further 30 min, cooled to 25 ° C and filtered.

The solid of the resulting aqueous dispersion AD1 was determined for the reaction control. The result together with the pH value and the specific particle size are given in Table 1 .2. Table 1 .1: Aqueous dispersion AD1 containing a multistage polyacrylate

Table 1 .2: Key data of the aqueous dispersion AD1 or of the polymer containing

AD1

Solid content [% by weight] 25.6

pH 8.85

Particle size [nm] 246 2. Preparation of Thickening Agents

2.1 Polyamide Thickener V1

22.5 parts of an aqueous dispersion of a polyester prepared according to Example D, column 16, Z. 37-59 of DE 40 09 858 A1, 0.45 parts of dimethylethanolamine, 3 parts of 2,4,7,9-tetramethyl-5 decindiol, 52% in butyl glycol (available from BASF SE), 3 parts Lipotin® A (available from Evonik Industries AG), 56.05 parts deionized water and 15 parts of Disparlon® A670-20M (available from Kusomoto Chemicals, Ltd.). ) are stirred together with stirring at a temperature of 15-25 ° C to a mixture. Subsequently, this mixture is homogenized at the aforementioned temperature with stirring over a period of 10 minutes by means of the device "Dispermat® LC30" from VWA-Getzmann, Germany with a peripheral speed of the stirring disk used of 15 to 20 m / s with stirring.

2.2 Polyamide Thickener V2

7.63 parts of an aqueous dispersion of a polyester prepared according to Example D, column 16, Z. 37-59 of DE 40 09 858 A1, 24.52 parts of a melamine-formaldehyde resin (Cymel® 303 from Allnex), 0.33 parts of dimethylethanolamine , 12.79 parts of 2,4,7,9-tetramethyl-5-decynediol, 52% in butylglycol (available from BASF SE), 29.82 parts of butylglycol and 14.91 parts of Disparlon® A670-20M (available from Kusomoto Chemicals, Ltd.) are stirred into a mixture with stirring at a temperature of 15-25 ° C. Subsequently, this mixture is homogenized at the aforementioned temperature with stirring over a period of 10 minutes by means of the device "Dispermat® LC30" from VWA-Getzmann, Germany with a peripheral speed of the stirring disk used of 15 to 20 m / s with stirring.

3. Preparation of pigment pastes and filler pastes

3.1 Production of a non-inventive white paste wP1

The white paste is made from 50 parts by weight of titanium rutile 2310, 6 parts by weight of a polyester prepared according to Example D, column 16, Z. 37-59 of DE 40 09 858 A1, 24.7 parts by weight of a patent EP 0 228 003 B2, p , Z. 6 to 18 polyurethane dispersion prepared, 10.5 parts by weight of deionized water, 4 parts by weight of 2,4,7,9-tetramethyl-5-decynediol, 52% in butylglycol (available from BASF SE), 4.1 parts by weight of butylglycol, 0.4 parts by weight 10% iges dimethylethanolamine in water and 0.3 parts by weight of Acrysol® RM-8 (available from The Dow Chemical Company).

3.2 Production of a white paste wP2 according to the invention

The white paste is composed of 34 parts by weight of titanium rutile 2310, 43.3 parts by weight of the aqueous dispersion AD1 described under point 1. 16.7 parts by weight of deionized water, 2.1 parts by weight of Disperbyk® 184 (available from BYK-Chemie GmbH) and 3.9 parts by weight Butyl glycol produced.

3.3 Preparation of a non-inventive white paste wP3

The white paste is from 44.26 parts by weight of titanium rutile 2310, 9.93 parts by weight of a melamine-formaldehyde resin (Cymel® 203 from Allnex), 10.95 parts by weight of a polyester prepared according to Example D, column 16, Z. 37-59 DE 40 09 858 A1, 5.32 parts by weight of a polyurethane-modified polyacrylate, prepared according to page 7, Z. 55 to page 8, Z. 23 of DE 4437535 A1, 21, 73 parts by weight deionized water, 2.73 parts by weight Disperbyk® 184 (available BYK-Chemie GmbH) and 5.08 parts by weight of butylglycol.

3.4 Preparation of black paste sP1

The black paste is composed of 57 parts by weight of a polyurethane dispersion prepared according to WO 92/15405 A1, page 14, line 13 to page 15, line 13, 10 parts by weight of carbon black (Monarch® 1400 carbon black from Cabot Corporation), 5 parts by weight of a polyester , prepared according to Example D, column 16, Z. 37-59 of DE 40 09 858 A1,

6.5 parts by weight of a 10% aqueous dimethylethanolamine solution, 2.5 parts by weight of a commercial polyether (Pluriol® P900, available from BASF SE), 7 parts by weight of butyldiglycol and 12 parts by weight of deionized water. 3.5 Preparation of a yellow paste gP1

The yellow paste is made from 37 parts by weight of Bayferrox® 3910 (available from Lanxess), 49.5 parts by weight of an aqueous binder dispersion prepared according to WO 91/15528 A1, p. 23, lines 26 to 24, Z. 24, 7, 5 parts by weight Disperbyk® 184 (available from BYK-Chemie GmbH) and 6 parts by weight deionized water.

3.6 Preparation of a yellow paste gP2

The yellow paste is composed of 47 parts by weight of Sicotan Yellow L 1912, 45 parts by weight of an aqueous binder dispersion prepared according to WO 91/15528 A1, p. 23, line 26 to page 24, line 24, 2.7 parts by weight of 1-propoxy-2 -propanol, 2.8 parts by weight of deionized water, 1.5 parts by weight of Disperbyk®-184 (available from BYK-Chemie GmbH) and 1 part by weight of Aerosil® R 972 (available from Evonik Industries).

3.7 Preparation of a Barium Sulfate Paste BSP1

The barium sulfate paste is composed of 39 parts by weight of a polyurethane dispersion prepared according to EP 0 228 003 B2, page 8, lines 6 to 18, 54 parts by weight of barium sulfate (blanc fixe micro from Sachtleben Chemie GmbH), 3.7 parts by weight of butylglycol and 0.3 part by weight Agitan® 282 (available from Münzing Chemie GmbH) and 3 parts by weight of deionized water.

3.8 Preparation of a talcum paste TP1

The talc paste is from 49.7 parts by weight of an aqueous binder dispersion prepared according to WO 91/15528, page 23, Z. 26 to page 24, Z. 24, 28.9 parts by weight of steatite (Microtalc IT extra from Mondo Minerals BV), 0.4 parts by weight of Agitan® 282 (available from Münzing Chemie GmbH), 1.45 parts by weight of Disperbyk®-184 (available from BYK-Chemie GmbH), 3.1 parts by weight of a commercially available polyether (Pluriol® P900, available from BASF SE) and 16.45 parts by weight of deionized water. 4. Preparation of aqueous basecoats

4.1 Preparation of a waterborne basecoat WBL A1 not according to the invention and a waterborne basecoat WBL A2 according to the invention

The components listed under "aqueous phase" in Table 4.1 are stirred together in the stated sequence to give an aqueous mixture.

Then it is stirred for 10 minutes and using deionized water and

Dimethylethanolamin to a pH value of 8.1 ± 0.2 and a spray viscosity of

95 ± 5 mPa-s at a shear stress of 1000 s ^-1 , measured with a rotary viscometer (Rheolab QC device with temperature control system C-LTD80 / QC from the company

Anton Paar) at 23 ° C.

Table 4.1: Preparation of waterborne basecoats WBL A1 and WBL A2

WBL A1 WBL A2

Aqueous phase:

3% Na-Mg layered silicate solution 15.23 15.23

1-propoxy-2-propanol 1, 41 1, 41

2-ethylhexanol 0.87 0.87

Aqueous binder dispersion AD1 31, 23 21, 48

Polyester; prepared according to Example D, column 16, Z. 37-59

4,85 6,00

DE 40 09 858 A1

Melamine-formaldehyde resin (Cymel® 203 from Allnex) 5,44 5,44

10% dimethylethanolamine in water 0.30 0.30

2,4,7,9-Tetramethyl-5-decynediol, 52% in butylglycol 1, 09 1, 09

Triisobutyl phosphate 1, 63 1, 63

Polyurethane-modified polyacrylate; manufactured according to p. 7,

2.91 2.91

Z. 55 to p.8, Z. 23 of DE 4437535 A1

Butyl glycol 4.35 4.35

Isopar® L, available from Exxon Mobile 1, 84 1, 84

Pluriol® P900, available from BASF SE 0.54 0.54

Hydrosol A170, available from DHC Solvent Chemie GmbH 0.54 0.54

White paste wP1 (not according to the invention) 25.68 - White paste wP2 (according to the invention) - 37.76

Black paste sP1 1, 52 1, 52

Yellow paste gP1 0,54 0,54 4.2 Preparation of a noninventive waterborne basecoat WBL A3 and a waterborne basecoat WBL A4 according to the invention

The components listed under "aqueous phase" in Table 4.2 are stirred together in the order indicated to give an aqueous mixture, which is then stirred for 10 minutes and brought to a pH of 8.1 ± 0.2 and a spray viscosity of 90 using deionized water and dimethylethanolamine -1 0 mPa-s at a shear stress of 1000 s ^"1 , measured with a rotary viscometer (Rheolab QC with tempering C-LTD80 / QC Anton Paar) at 23 ° C, set.

Table 4.2: Preparation of the aqueous basecoat WBL A3 and WBL A4

4.3 Preparation of a Waterborne Basecoat WBL B1 Not According to the Invention and a Waterborne Basecoat WBL B2 According to the Invention

The components listed under "aqueous phase" in Table 4.3 are stirred together in the order indicated to give an aqueous mixture, which is then stirred for 10 minutes and brought to a pH of 8 and a spray viscosity of 90% with the aid of deionized water and dimethylethanolamine. 100 mPa-s at a shear stress of 1000 s ^{~ 1} , measured with a rotary viscometer (Rheolab QC device with temperature control system C-LTD80 / QC Anton Paar) at 23 ° C, adjusted.

Table 4.3: Preparation of waterborne basecoats WBL B1 and WBL B2

4.4 Preparation of a Waterborne Basecoat WBL B3 Not According to the Invention

The components listed under "aqueous phase" in Table 4.4 are stirred together in the order listed to form an aqueous mixture, which is then stirred for 10 minutes and brought to a pH of 8 and a spray viscosity of 90 ± 5 using deionized water and dimethylethanolamine mPa-s at a shear stress of 1000 s ^" \ measured with a rotary viscometer (device Rheolab QC with temperature control system C-LTD80 / QC Anton Paar) at 23 ° C, adjusted.

Table 4.4: Preparation of water-based paint WBL B3

WBL B3

Aqueous phase:

Thickener V2 15,09

deionized water 17.40

n-propanol 0.79

n-butoxypropanol 1, 24

2-ethylhexanol 2.49

Aqueous binder dispersion AD1 41, 00

BYK-346, available from / BYK-Chemie GmbH 0.41

Isopropanol 1, 48

Butyl glycol 0.90

Isopar® L, available from Exxon Mobile 0.79

Black paste sP1 12,60

Barium sulphate paste BSP1 2,88

Talc p TP1 2.93

Total: 100.00

4.5 Preparation of a waterborne basecoat WBL B4 not according to the invention

The components listed under "aqueous phase" in Table 4.5 are stirred together in the stated order to form an aqueous mixture, and in the next step, an organic mixture is prepared from the components listed under "organic phase". The organic mixture is added to the aqueous mixture. The mixture is then stirred for 10 minutes and with the aid of deionized water and dimethylethanolamine to a pH of 8 and a spray viscosity of 85-90 mPa-s at a shear stress of 1000 s ^"1 , measured with a rotary viscometer (Rheolab QC device with Temperature control system C-LTD80 / QC Anton Paar) at 23 ° C, set. Table 4.5: Preparation of water-based paint WBL B4

WBL B4

Aqueous phase:

3% Na-Mg layered silicate solution 20.70 deionized water 12.50

1-Propoxy-2-propanol 2.20 n-butoxypropanol 1, 65 isopropanol

2-ethylhexanol 2.50

Aqueous binder dispersion AD1 26.00

Polyester; prepared according to Example D, column 16, Z. 37-59

2.60 DE 40 09 858 A1

3% strength by weight aqueous Rheovis® AS 1 130 solution,

6,50 available from BASF SE

Melamine formaldehyde (Resimene® 755 from Ineos) 2,30

10% dimethylethanolamine in water 0.50

Pluriol® P900, available from BASF SE 1, 00

Polyurethane-modified polyacrylate; prepared according to S. "" "7, Z. 55 to S. 8, Z. 23 of DE 4437535 A1

Isobutanol 2.80

50% strength by weight solution of Rheovis® PU1250 in butylglycol 0.50

Tinuvin® 384-2, available from BASF SE 0.80

Tinuvin® 123, available from BASF SE 0.40

Byketol®-WS from BYK-Chemie GmbH 1, 00

Organic phase:

Mixture of two commercial aluminum pigments,

available from Altana-Eckart (Alu Stapa Hydrolux 4,55 2192 & 2197 in the ratio 2,4: 1, 0)

Butylglycol 5.60 polyester; prepared according to Example D, column 16, Z. 37-59, DE 40 09 858 A1

10% dimethylethanolamine in water 0.20

Total: 100.00 4.6 Preparation of a waterborne basecoat WBL A2a not having the same composition as the waterborne basecoat WBL A2 according to the invention

As a direct comparison to the waterborne basecoat WBL A2 according to the invention (preparation see 4.1), a nonaqueous waterborne basecoat WBL A2a was prepared which has an identical overall composition as WBL A2, but with regard to the method of preparation, i. the use of white paste, is different. The formulations of WBL A2 and WBL A2a are juxtaposed in Table 4.6.

For the production of WBL A2, the white paste wP2 according to the invention was used which contains the polymer (b) used according to the invention by using the dispersion AD1. For the preparation of WBL A2a, however, the non-inventive white paste wP3 was used, which does not contain this polymer (b). Compared to wP2, in wP3, the proportion of the polymer (b) contained in wP2 was replaced by the binder components (melamine-formadehyde resin, polyester and polyurethane-modified polyacrylate) contained in WBL A2. The amount of separately used polymer (b) was correspondingly increased in the production of WBL A2a, but the proportion of the remaining binder components was reduced so that both formulations have an exactly identical overall composition.

The preparation of WBL A2a is analogous to WBL A2 (see 4.1); with the aid of deionized water and dimethylethanolamine is adjusted to a pH of 8 and a spray viscosity of 95 ± 5 mPa-s at a shear stress of 1000 s ^"1 , measured with a rotary viscometer (Rheolab QC device with temperature control system C-LTD80 / QC the company Anton Paar) at 23 ° C, set. Table 4.6: Preparation of the water-base lacquer WBL A2 (according to the invention) and WBL A2a (non-inventive)

WBL A2a WBL A2

Aqueous phase:

3% Na-Mg layered silicate solution 15.23 15.23

1 - Propoxy-2-propanol 1, 41 1, 41

2-ethylhexanol 0.87 0.87

Aqueous binder dispersion AD1 37.83 21, 48

Polyester; prepared according to Example D,

2,82 6,00

Column 16, Z. 37-59 of DE 40 09 858 A1

Melamine formaldehyde resin (Cymel® 203

2.56 5.44

the company Allnex)

10% dimethylethanolamine in water 0.30 0.30

2,4,7,9-Tetramethyl-5-decynediol, 52% in butylglycol 1, 09 1, 09

Triisobutyl phosphate 1, 63 1, 63

Polyurethane modified polyacrylate; produced

1, 37 2.91

according to S. 7, Z. 55 to S. 8, Z. 23 of DE 4437535 A1

Butyl glycol 4.35 4.35

Isopar® L, available from Exxon Mobile 1, 84 1, 84

Pluriol® P900, available from BASF SE 0.54 0.54

Hydrosol A170, available from DHC

0.54 0.54

Solvent Chemistry GmbH

White paste wP3 (non-inventive) 29.01 - white paste wP2 (according to the invention) - 37.76

Black paste sP1 1, 52 1, 52

Yellow paste gP1 0,54 0,54

Total: 103.45 03.45

5. Investigations and comparison of the properties of the aqueous basecoats and the coatings obtained therefrom

5.1 Comparison between WBL A1 and WBL A2

The investigations on the waterborne basecoat WBL A1 not according to the invention as well as on the aqueous basecoat WBL A2 according to the invention (containing a pigment paste according to the invention based on the polymer (b)) with regard to storage stability, cooker, runner, pinholes, the appearance of specks, the Tendency to segregation and with respect to the layer thickness-dependent course were carried out according to the methods described above. Tables 5.1 to 5.5 summarize the results.

Table 5.1: Results of the tests with regard to storage stability

Water-based paint

WBL A1 WBL A2

Niederscherfrisch 1306.3 2684.6 viscosity (1 s- ¹ ) after 2 weeks storage at 40 ° C 757.4 2649.6 in mPa's change [%] -42% -1%

High shear fresh 98.5 98.5 viscosity (1000 s ^-1 ) after 2 weeks storage at 40 ° C 88.6 110.2 in mPa.s Change [%] -10% 12%

Table 5.2: Results of studies on segregation tendency and pigment agglomerates (specks)

Water-based paint

WBL A1 WBL A2

Visual assessment for segregation 2-3 1

Visual assessment for appearance

pigment agglomerates

on glass panels:

on metal sheets:

Table 5.3: Results Investigations regarding cooker run tendency

Water-based paint

WBL A1 WBL A2

Runner start (> 0 mm) [μιη]> 30> 30

Cooker limit [pm]>30> 30 Table 5.4: Results of tests for pinholes

Number of pinholes (normalized to 200 cm ² ):

Layer thickness range basecoat

WBL A1 WBL 2

(Painting of the wedge according to variant A)

0-20 μιη 0 0

20 μιη - end of the wedge 0 0

Sum 0 0

Table 5.5: Results of tests on layer thickness-dependent course (painting according to variant A)

Water-based paint

Thickness range

Appearance WBL A1 WBL A2

{Varnishing of the wedge according to variant A)

10 μπΊ - 15 μηι 24.0 16.5

15 μηι - 20 μηι 18.0 17.5

SW 20 μηι - 25 μηι 19.9 18.9

25 μηι - 30 μηι 24.4 21, 6

30 μιτι - 35 μπι 30.9 23.4

10 μηι - 15 μιτι 4.8 3.5

15 μιη - 20 μηι 4.3 3.8

LW 20 μίϊΐ - 25 μηι 4.7 3.7

25 μm - 30 μm 5.8 4.5

30 μιτι - 35 microns 7.9 4.9

10 μm - 15 μm 88.5 90.9

15 m - 20 μm 91, 3 90.3

DOI 20 ηη - 25 μηη 90.1 88.8

25 μm - 30 m 88.1 86.7

30 μm - 35 μm 83.3 84.7

WBL Α1 and WBL A2 each have a very good pinhole robustness and show comparatively good properties with respect to cookers and runners. The use of the white paste wP2 according to the invention in the aqueous basecoat WBL A2 leads to an improved storage stability compared to WBL A1 containing the non-inventive white paste wP1; the viscosity level in the low-shear range hardly changes in the case of WBL A2 due to storage in the oven, whereas in the case of WBL A1 a significant drop in the low-shear viscosity is measured. Along with this, WBL A2 has a markedly lower tendency towards phase separation or segregation found during furnace storage. In addition, WBL A2 is distinguished from WBL A1 by a better layer thickness-dependent course.

5.2 Comparison between WBL B1 and WBL B2 and between WBL A3 / WBL B1 and WBL A4 / WBL B2

The investigations on the water-based paints WBL B1 and WBL B2 or multilayer constructions using water-based paints WBL A3 and WBL B1 (in each case not according to the invention) or WBL A4 and WBL B2 (each according to the invention) in terms of hiding power, runners, pinholes and with respect to the layer thickness-dependent course made according to the methods described above. Tables 5.6 to 5.9 summarize the results.

Table 5.6: Results of studies on hiding power and runners

Water-based paint

WBL B1 WBL B2

Hiding power [μιτι] 24 21

Runner start (> 0 mm) [μηι] 9 15

Runner limit (> 10 mm) [μιη] 18 23

Table 5.7: Results of tests for pinholes

Number of pinholes (normalized to 200 cm ² ):

Paint according to variant C

Painting 1. Water-based paint constant WBL A3 WBL A4

Paint finish 2. Water-based paint as wedge WBL B1 WBL B2

Layer Thickness Area Basecoat Total Layer

(Water-based paint 1 + water-based paint 2)

0-20 pm 1 0

20 μιη - end of the wedge 1 0

Sum 2 0 Table 5.8: Results of investigations with regard to layer thickness-dependent course (varnishes according to variant B)

Paint according to variant B

Painting 1. Water-based paint as wedge WBL A3 WBL A4

Paint finish 2. Water-based paint constant WBL Β1 WBL Β2

Appearance coating thickness range 1. Basecoat WBL A3 WBL A4

5 μηι - 10 μηη 13.6 10.5

10 μηη - 15 μηπ 16.4 13.3

SW 15 μιη - 20 μηπ 19.8 13.9

20 μηι - 25 μηΊ 23.7 16.2

25 μηι - 30 μηι 26.1 17.5

5 μιη - 10 μηι 4.0 4.6

10 μηπ - 15 μπΊ 4.9 5.3

LW 15 μιη - 20 μηι 6.0 5.6

20 μπΊ - 25 μηι 6.6 6.0

25 μηπ - 30 μηη 7.3 5.3

5 μιη - 10 μηπ 90.8 93.5

10 μηη - 15 μιη 86.5 91, 7

DOI 15 μιτι - 20 μηι 82.0 91, 6

20 μιτι - 25 μηι 81, 4 89.8

25 μηι - 30 μηι 81, 1 89.4

Table 5.9: Results of investigations with regard to coating thickness-dependent course (coatings according to variant C)

Paint according to variant C

Painting 1. Water-based paint constant WBL A3 WBL A4

Paint finish 2. Water-based paint as wedge WBL Β1 WBL Β2

Appearance coating thickness range 2. Base coat WBL Β1 WBL Β2

5 μητι - 10 m 21, 6 19.9

10 μιη - 15 μηπ 21, 7 17.2

SW 15 μιη - 20 μηι 23.7 18.1

20 μηι - 25 μηΊ 21, 8 17.0

25 μηπ - 30 μιη 23.5 16.4

5 μηι - 10 μηη 6.0 4.9

10 μηη - 15 μιη 5.4 5.3

LW 15 μηη - 20 μηη 5.2 5.4

20 μηι - 25 μηη 5.5 5.1

25 μηι - 30 μηι 5.9 6.6

5 μηη - 10 μιη 80.6 87.3

10 μπη - 15 μηι 79.9 87.0

DOI 15 μηη - 20 μιη 79.2 87.3

20 μηι - 25 μηι 81, 3 89.0

25 μηΊ - 30 μηι 81, 4 89.8

The results show that by using the white paste wP2 according to the invention, the course can be influenced significantly positively. Furthermore, a slightly better pinhole robustness is found compared to the non-inventive multi-layer construction (use of WBL A3 and WBL B1). The aqueous basecoat WBL B2, containing the white paste wP2 according to the invention based on a multi-stage polyacrylate, not only has a better runner resistance compared to the reference WBL B1, but is also characterized by a better hiding power. 5.3 Comparison between WBL A3 / WBL B3 and WBL A4 / WBL B3

The investigations on the multi-layer structures using the aqueous basecoat materials WBL A3 and WBL B3 (not according to the invention) or WBL A4 and WBL B3 (according to the invention) with regard to the layer thickness-dependent course were carried out according to the methods described above. Tables 5.10 and 5.1.1 summarize the results.

Table 5.10: Results of investigations with regard to coating thickness-dependent course (coatings according to variant B)

Paint according to variant B

Painting 1. Water-based paint as wedge WBL A3 WBL A4

Paint finish 2. Water-based paint constant WBL Β3 WBL Β3

Appearance coating thickness range 1. Basecoat WBL A3 WBL A4

5 pm - 10 μιτι 10.6 10.2

10 μιτι - 15 μιτι 1 1, 0 11, 3

SW

15 μιη - 20 μιη 13.5 12.2

20 μΓη - 25 μηπ 15.7 13.8

5 μιη - 10 μηι 96.2 95.5

10 μηι - 15 μηι 95.7 95.3

DOI

15 μΓη - 20 μηΊ 94.4 94.7

20 μηη - 25 μπη 93.1 93.6

Table 5.1 1: Results of investigations with regard to coating thickness-dependent course (coatings according to variant C)

Paint according to variant C

Painting 1. Water-based paint constant WBL A3 WBL A4

Paint finish 2. Water based paint as wedge WBL Β3 WBL Β3

Appearance coating thickness range 2. Base coat WBL Β3 WBL Β3

5 μιτι - 10 μιη 16.4 13.4

10 μηι - 15 μηπ 17.4 13.0

SW 15 μιη - 20 μηη 18.1 14.0

20 μηη - 25 μηπ 18.5 13.1

25 μι - 30 μηι 18.9 14.0

5 μιη - 10 μηη 89.1 93.1

10 μηι - 15 μηι 88.4 94.3

DOI 15 μηι - 20 μηη 88.0 93.8

20 μηπ - 25 μι 89.2 94.2

25 μηι - 30 μηι 90.2 93.4

The results show that the use of the white paste wP2 according to the invention comprising the multistage polyacrylate AD1 brings advantages over the reference pastes used. This can be seen especially in short wave (SW) especially at higher layer thicknesses as well as in the image sharpness (DOI) in the entire layer thickness range.

5.4 Comparison between WBL A3 / WBL B4 and WBL A4 / WBL B4

The investigations on the multi-layer constructions using the aqueous basecoat materials WBL A3 and WBL B4 (not according to the invention) or WBL A4 and WBL B4 (according to the invention) with regard to the occurrence of pinholes were carried out according to the methods described above. Table 5.12 summarizes the results. Table 5.12: Results of studies on the occurrence of pinholes

Number of pinholes (normalized to 200 cm ² ):

Paint according to variant C

Painting 1. Water-based paint constant WBL A3 WBL A4

Paint finish 2. Water-based paint as wedge WBL B4 WBL B4

Layer Thickness Area Basecoat Total Layer

(Water-based paint 1 + water-based paint 2)

0-20 pm 0

20 μιτι - end of the wedge 18

Total 18

The use of the white paste wP2 according to the invention in the multi-layer structure using the waterborne basecoats WBL A4 and WBL B4 leads to a significantly better pinhole robustness compared to the reference.

5.5 Comparison between the waterborne basecoat WBL A2a not according to the invention and the waterborne basecoat WBL A2 according to the invention with regard to the layer thickness-dependent course

The results of these tests on the aqueous basecoat materials WBL A2a (not according to the invention) and WBL A2 (according to the invention), which took place according to the method described above, are summarized in Tables 5.13 below.

Table 5.13: Results of the investigations regarding the layer-thickness-dependent course

Water-based paint

, Thickness range

Appearance ^ _of ^ ^ ^ _A) WBL A2 WBL A2a

10 pm - 15 pm 3.5 8.7

15mm - 20mm 3.8 8.3

LW

20m - 25mm 3.7 9.7

25mm - 30mm 4.5 9.7

10 μπι - 15 M 90.9 90.5 15 mm - 20 mm 90.3 88.5

DOI

20 μπΊ - 25 μm 88.8 84.8 25 μm - 30 μm 86.7 84.7 The results show that, the water-based lacquer WBL A2, which was prepared by means of a color pigment paste (wP2) according to the invention, compared to a water-based lacquer same composition (WBL A2a), which has been prepared by means of a non-inventive color pigment paste (wP3), has other and especially advantageous properties with respect to long wave (LW) and DOI and thus in terms of Appearance. These results show that only by the manufacturing process WBL A2 has different properties than WBL A2a.

Claims

claims:

1. comprising an aqueous pigment paste

(c) at least one colored pigment and

(D) at least one polymer having an average particle size in

and where

iii. then the mixture (C) in the presence of under ii. polymerized polymerized.

2. The pigment paste according to claim 1, characterized in that it contains the color pigment (a) in an amount of at least 5 wt .-%, based on the total weight of the pigment paste.

3. The pigment paste according to claim 1 or 2, characterized in that it contains as at least one color pigment (a) a white pigment.

The pigment paste according to any one of the preceding claims, characterized in that it contains at least one color pigment (a) titanium dioxide.

The pigment paste according to any one of the preceding claims, characterized in that the relative weight ratio of the at least one color pigment (a) to the polymer (b) in the pigment paste is in a range from 10: 1 to 1:10.

The pigment paste according to any one of the preceding claims, characterized in that it contains the polymer (b) in an amount in the range of from 5 to 20% by weight, based on the total weight of the pigment paste.

The pigment paste according to one of the preceding claims, characterized in that the proportion of the mixture (A) used for the preparation of the polymer (b) from 0.1 to 10 wt .-%, the proportion of the mixture used to prepare the polymer (b) (B) from 60 to 80 wt .-% and the proportion of the mixture used for the preparation of the polymer (b) mixture (C) of 10 to 30 wt .-%, each based on the sum of the individual amounts of the mixtures (A), ( B) and (C).

The pigment paste according to one of the preceding claims, characterized in that the mixture (A) at least one monounsaturated ester of (meth) acrylic acid with an alkyl radical and at least one vinyl group-containing mono-olefinically unsaturated monomer having a radical arranged on the vinyl group, the aromatic or which is mixed saturated aliphatic-aromatic, in which case the aliphatic moieties of the residue are alkyl groups.

The pigment paste according to any one of the preceding claims, characterized in that the mixture (B) in addition to the at least one poly-olefinically unsaturated monomer nor at least one monounsaturated ester of (meth) acrylic acid with an alkyl radical and at least one vinyl group-containing mono-olefinically unsaturated monomer one moiety located on the vinyl group which is aromatic or which is mixed saturated aliphatic-aromatic, in which case the aliphatic moieties of the moiety are alkyl groups.

10. The pigment paste according to any one of the preceding claims, characterized in that the mixtures (A) and (B) contain no hydroxy-functional monomers and no acid-functional monomers.

1 1. The pigment paste according to any of the preceding claims, characterized in that the mixture (C) comprises at least one alpha-beta-unsaturated carboxylic acid, at least one monounsaturated ester of (meth) acrylic acid with an alkyl radical substituted by a hydroxyl group and at least one monounsaturated ester of the ( Meth) acrylic acid containing an alkyl radical.

12. The pigment paste according to one of the preceding claims, characterized in that in stages i. to iii. For the preparation of the polymer (b) the addition of the olefinically unsaturated monomers is carried out so that in the reaction solution, a proportion of free monomers of 6.0 wt .-%, based on the total amount of the monomers used in the respective polymerization stage, not during the entire reaction time is exceeded.

13. An aqueous basecoat, characterized in that the basecoat is preparable by admixing at least one pigment paste according to one of claims 1 to 12 as component (1) to at least one suitable for preparing a basecoat aqueous component (2), which at least one as a binder contains usable polymer, wherein this polymer can be used as a binder to the polymer also contained in the pigment paste (b) and / or is at least one of them different polymer.

14. A process for producing a multicoat paint system, in which

(1a) an aqueous basecoat is applied to a substrate,

(2a) a polymer film is formed from the lacquer applied in step (1a), (1 b) if desired, a further aqueous basecoat material is applied to the polymer film thus formed,

(2b) optionally from the paint applied in step (1b)

Polymer film is formed,

(3) a clearcoat is applied to the basecoat layer (s) so obtained, and then

(4) the basecoat film (s) is co-cured together with the clearcoat film, which is characterized in that the basecoat film according to claim 13 in step (1 a) or - if the process also comprises the steps (1 b) and ( 2b) - in step (1 a) and / or (1 b) is used.

5. A use of a polymer having a particle size in the range of 100 to 500 nm, preparable by successive free radical emulsion polymerization of three monomer mixtures (A), (B) and (C) of olefinically unsaturated monomers in water, wherein

and where

i. first the mixture (A) is polymerized, ii. then the mixture (B) in the presence of under i. polymerized polymerized, and iii. Thereafter, the mixture (C) is polymerized in the presence of the polymer produced, for the dispersion of color pigments within a pigment paste.