EP2108463B1 - Method for manufacturing effect finishes and their application - Google Patents

Description

The present invention relates to a process for the production of effect finishes. The invention furthermore relates to the use of these effect finishes as or in coating compositions or for coating metals, in particular bodies and body parts, as well as plastics, plastic films, paper, cardboard, leather, glass, textiles and ceramics. Furthermore, the invention relates to multi-layer coating obtainable by the aforementioned method.

An effect finish is a finish in which a deliberate detectable irregularity is evenly distributed over the surface. Examples of effects include hammered, textured, dab, metal, suede, velvet, or thermochromic effects (from: Rompp Lexikon Lacke and Colors, Georg Thieme Verlag, Stuttgart 1998, ISBN 3-13-776001-1 , Keywords "effect painting" and "effect paints").

The optical effects can be caused, for example, by effecting or color and effect coating agents. These coating agents cause a change in the color impression, the brightness and / or the reflectivity when varying the viewing direction (of the supervisor angle). They usually have a platelet-shaped structure, d. H. that the thickness of the pigment particles is significantly smaller than their lateral extent. Known examples of colorants or effect agents are aluminum flakes or the pigments which are marketed under the names Mica®, Iriodin® or Paliochrom®. Metallic effect pigments, e.g. B. aluminum flakes, cause a mirror effect when viewed vertically; when viewed from the side this does not appear. It is therefore observed a light-dark effect. The same phenomenon is also found in the mica effect pigments based on mica.

Iriodin and paliochrome pigments additionally show increased interference effects or self-absorption. In addition to the light-dark effect, they also show a slight change in color when the viewing angle is changed. (Literature: " Pearlescent pigments ", Vincentz Verlag, ISBN 3-87870-429-1 ).

As effect-imparting or color and effect-imparting coating compositions are, for example, also dispersed core / shell particles whose shell is filmable. After (partial) removal of the liquid phase, the previously uncrosslinked shell films and forms a continuous matrix. So the shell forms the later matrix. Therein, the cores of the particles remain as discrete polymer particles and arrange themselves regularly (the cores form the later discrete polymer particles). This coating agent (also referred to in the art as a colored polymer system) causes an optical effect. This is due to reflection by interference of the light scattered on the polymer particles. The wavelength of the reflection to be observed depends on the known Bragg equation from the interplanar spacing, ie the distance between the polymer particles arranged in a space lattice structure in the matrix. The existence of the space lattice structure is demonstrated, among other things, by the visual perception of an effect.

Out DE-19717879 . DE-19820302 and DE-19834194 For example, colored polymer systems are known in which discrete polymer particles are dispersed in a matrix. It is in the DE-19717879 produced by a multiple spraying a coating, wherein between the individual spraying the last applied layer is dried in air.

In DE 10229732 the use of such polymer layers in optical display elements is described.

The WO 03/044911 discloses a solid state dye laser amplifying medium whose feedback medium is a polymeric dispersion film of crystalline structure, particularly comprising fusible core / shell particles.

WO 2004/098793 describes a process for improving the color brilliance of colored polymer systems in which the polymer particles have an intermediate layer between the core and shell as a transition stage.

The patent application DE 10321079 also discloses a method of improving color brilliance. This is achieved by annealing the polymer layer. Out WO 2004/099330 Methods are known in which a transparent polymer layer is applied to an effect or color and effect coating.

In the application of the core / shell dispersions, it has hitherto been problematic to maintain or maintain the color effect on the coated material. This problem was particularly evident in workpieces that have no flat, but for example curved or angled surfaces. For this purpose, for example, to count bodies and their parts. Often the effect decreased or was completely lost. In addition, the results of the application, which should lead to the effects, little or no reproducible.

The object of the present invention was to eliminate the disadvantages of the prior art described above. Application methods were to be found with which effect coatings of core / shell dispersions could be produced with reproducible induction and lasting retention of the effect. The effect coatings obtained should have good color brilliance and high stability in the effecting or color and effect coating agent.

Surprisingly, application methods were found in which the effect finishes could be produced permanently and reproducibly. Accordingly, a process for the production of effect finishes has been found, which is characterized in that an effect or color and effect coating agent, which consists of a matrix and discrete polymer particles, applied by a sputtering process once and then completely or partially by total or partial volatilization of dried liquid phase.

It was particularly surprising here that a particularly good inventive effect is obtained with only a single application of the effect or color and effect coating agent.

The one-time application means the application in one step without intermediate drying steps.

Sputtering processes for the application of paints and coating materials are known and are described, for example, in Kittel: Textbook of coatings and coatings, Volume 9: Processing of paints and coating materials, 2nd edition, S. Hirzel Verlag Stuttgart, Leipzig 2004, ISBN 3-7776-1102-4 , Preferably spray-coating methods without electrostatic paint charging are selected as the sputtering method. The compressed air atomization, also called spray coating process, is particularly preferred. In ink-jet printing (also called ink-jet process), which is not part of the present invention, the effecting or color and effect coating agent is added in the form of ink in cartridges and applied via an inkjet printer. Inks containing core / shell particles as effecting or color and effect coating agents are described, for example, in US Pat EP-A 0955323 called.

The effect or color and effect coating agent is preferably applied in a layer thickness of 0.2 to 500 .mu.m, preferably from 1 to 200 .mu.m, more preferably from 1 to 100 .mu.m and in particular from 2 to 50 microns.

After application of the effecting or color and effect coating agent, the coating is advantageously dried for 30 s to 5 min at room temperature (about 20 ° C) and then for 30 s to 5 min at 45 ° C.

The effect or color and effect coating agent can be applied manually or automatically, in high pressure or low pressure or by airless spraying with or without air support. In the sputtering process, especially in the spray-coating process, it is advantageous to apply the effect-giving or color and effect coating agent with a pressure of 2 to 5 bar. Particularly advantageous is a pressure of 2.5 to 3.5 bar, in particular 3.0 bar. For example, the effecting or color and effect coating agent can be applied manually with a high-performance paint spray gun. The distance between substrate and coating unit is advantageously in the range of 10 to 100 cm, particularly advantageously from 30 to 40 cm.

Effect-giving or color and effect coating compositions with a core / shell structure are known in the art and are described, for example, in the prior art mentioned above. They consist of cores which are distributed as discrete polymer particles in a matrix, formed from filmable or film-coated shells, in a defined space lattice structure. Due to the core / shell structure, the effecting or color and effect coating agent may also be referred to as multi-phase.

To the polymer particles

worin D₉₀, D₁₀ und D₅₀ Teilchendurchmesser bezeichnen, für die gilt:

• D₉₀: 90 Gew.-% der Gesamtmasse aller Teilchen haben einen Teilchendurchmesser kleiner oder gleich D₉₀,
• D₅₀: 50 Gew.-% der Gesamtmasse aller Teilchen haben einen Teilchendurchmesser kleiner oder gleich D₅₀,
• D₁₀: 10 Gew.-% der Gesamtmasse aller Teilchen haben einen Teilchendurchmesser kleiner oder gleich D₁₀.

To form a defined space lattice structure, the discrete polymer particles should be as equal as possible. A measure of the uniformity of the polymer particles is the so-called polydispersity index, calculated according to the formula $$\mathrm{P},\mathrm{I},=\left({\mathrm{D}}_{90}-{\mathrm{D}}_{10}\right)/{\mathrm{D}}_{50}$$

wherein D ₉₀ , D ₁₀ and D ₅₀ denote particle diameters for which:

• D ₉₀ : 90% by weight of the total mass of all particles have a particle diameter less than or equal to D ₉₀ ,
• D ₅₀ : 50% by weight of the total mass of all particles have a particle diameter less than or equal to D ₅₀ ,
• D ₁₀ : 10% by weight of the total mass of all particles have a particle diameter less than or equal to D ₁₀ .

Further explanations of the polydispersity index can be found, for example: In DE-A 19717879 (especially drawings page 1).

The particle sizes and distributions are determined by means of hydrodynamic fractionation (HDF), which is suitable for particle size ranges of about 20 to 1200 nm. She was working on a PSDA Particle Size Distributing Analyzer (From Polymer Labs) (Cartridge type No. 2 standard, measuring temperature 23.0 ° C., measuring time 480 s, UV detector with set wavelength of 254 nm).

The particle size after HDF describes the mean particle size of the particles present in the dispersion. In the HDF method, only the maximum peak is considered in determining the average particle size. The polydispersity index of HDF describes the particle size distribution of the average particle size from the HDF values, determined according to the above formula for the PI. The PI from HDF thus moves as a dimensionless number between 0 and 1, whereby higher numerical values have a higher polydispersity and thus a lower one Mean monodispersibility.

The polymer particles preferably have an average particle diameter (D ₅₀ value) in the range of 0.05 to 10 μm, particularly preferably 0.05 to 5 μm, very particularly preferably 0.05 to 1.1 μm. The polymer particles may be one type of particle or multiple particle types with different D ₅₀ value.

Each particle type has a polydispersity index preferably less than 0.6, more preferably less than 0.4, and most preferably less than 0.3 and especially less than 0.15.

The polymer particles are preferably one or more particle types having an average particle diameter in the range from 0.05 to 10 μm, particularly preferably from 0.05 to 5 μm, very particularly preferably from 0.05 to 1.1 μm, where each Particle has a polydispersity index less than 0.6.

In particular, the polymer particles consist of a single particle type. The D ₅₀ value is then preferably between 0.05 and 2 μm, more preferably between 100 and 500 nm.

Also polymer particles, which z. B. consist of two or three, preferably two with respect to the D ₅₀ value different particle types, can form a common lattice structure (crystallize), if for each particle species the above condition with respect to the polydispersity index is met. Are suitable z. B. mixtures in particle types with a D ₅₀ value of 0.3 to 0.5 microns and with a D ₅₀ value of 0.1 to 0.3 microns.

The polymer particles are preferably made of a polymer whose glass transition temperature (Tg) is higher than the film-forming temperature. Preferably, the glass transition temperature calculated via the Fox equation is greater than 30 ° C., more preferably greater than 50 ° C., and most preferably greater than 70 ° C., in particular greater than 90 ° C.

The film-forming temperature is the temperature at which the shell of the core / shell particles is filmed.

The monomer mixture of the core may also contain homopolymers of the monomers having a calculated Tg of less than 0 ° C, preferably less than -20 ° C, more preferably less than -30 ° C. The proportion of these monomers in all monomers of the core is preferably at least 5 wt .-%, more preferably at least 10 wt .-%, most preferably at least 20, in particular at least 30 or 40 wt .-%. The remaining monomers of the core are chosen so that the above Tg region of the core is satisfied. Due to the low glass transition temperatures of the monomers in the core, the elasticity of the effect coating is increased. In WO 2006/122936 describes methods that lead to improved elasticity by using these cores. As a result, so-called mechano-optical effects are possible. These are perceived by stretching or compression of plastic or elastic material on which the effect or color and effect coating composition is applied with improved elasticity, color changes as a function of the elongation / compression of the material.

The polymer particles preferably comprise at least 40% by weight, preferably at least 60% by weight, particularly preferably at least 80% by weight, of so-called main monomers.

The main monomers are selected from C ₁ -C ₂₀ -alkyl (meth) acrylates, vinyl esters of carboxylic acids containing up to 20 C atoms, vinylaromatics having up to 20 C atoms, ethylenically unsaturated nitriles, vinyl halides, vinyl ethers of alcohols containing 1 to 10 carbon atoms, aliphatic hydrocarbons having 2 to 8 carbon atoms and 1 or 2 double bonds or mixtures of these monomers.

These include, for example, (Meth) acrylic acid alkyl esters having a C 1 -C 10 -alkyl radical, such as methyl methacrylate, methyl acrylate, n-butyl acrylate, ethyl acrylate and 2-ethylhexyl acrylate. In particular, mixtures of (meth) acrylic acid alkyl esters are also suitable.

Vinyl esters of carboxylic acids having 1 to 20 carbon atoms are, for. As vinyl laurate, stearate, vinyl propionate, vinyl versatate and vinyl acetate.

Suitable vinylaromatic compounds are vinyltoluene, α- and p-methylstyrene, α-butylstyrene, 4-n-butylstyrene, 4-n-decylstyrene and preferably styrene. Examples of nitriles are acrylonitrile and methacrylonitrile.

The vinyl halides are chloro, fluoro or bromo substituted ethylenically unsaturated compounds, preferably vinyl chloride and vinylidene chloride.

To name as vinyl ethers are, for. As vinyl methyl ether or vinyl isobutyl ether. Vinyl ether is preferably from 1 to 4 C-containing alcohols.

As hydrocarbons having 2 to 8 carbon atoms and one or two olefinic double bonds may be mentioned butadiene, isoprene and chloroprene, with a double bond z. As ethylene or propylene.

Preferred main monomers are the C ₁ -C ₂₀ -alkyl acrylates and methacrylates, in particular C ₁ -C ₈ -alkyl acrylates and methacrylates, vinylaromatics, in particular styrene, and mixtures thereof, in particular also mixtures of the alkyl (meth) acrylates and vinylaromatics ,

Very particular preference is given to methyl acrylate, methyl methacrylate, ethyl acrylate, n-butyl acrylate, n-hexyl acrylate, octyl acrylate and 2-ethylhexyl acrylate, styrene and mixtures of these monomers.

The polymer particles are preferably chemically crosslinked. For this purpose, monomers having at least two polymerizable groups, for. As divinylbenzene or allyl methacrylate, be used (internal crosslinking). However, it is also possible to add crosslinkers (external crosslinking).

The polymerization of the monomers of the core and / or the shell can be carried out in the presence of a UV absorber. Accordingly, the polymer contains a UV absorber. Preferably, the polymerization of the core is carried out in the presence of an absorber for electromagnetic waves, in particular a UV absorber. As UV absorbers into consideration, for. B. hydroxybenzophenones or hydroxyphenylbenzotriazoles. Such UV absorbers are z. B. under the trade name Uvinul® 3033P known. The amount of absorber is preferably 0.1 to 5 wt .-%, particularly preferably 0.2 to 3 wt .-%, based on the total polymer. The entire amount is preferably used in the polymerization of the core. For example, the WO 2006/122936 Core / shell particles with UV absorbers. As a result, an improved color brilliance can be achieved.

Furthermore, the polymerization of the monomers of the core and / or the shell can be carried out in the presence of different emulsifiers. When emulsifiers having an ionic group (ionic emulsifiers) are used in the polymerization of the monomers of the core, emulsifiers without ionic groups (nonionic emulsifiers) are preferably used in the polymerization of the monomers of the shell. Conversely, in the polymerization of the monomers of the shell, ionic emulsifiers are used when the polymerization of the monomers of the core has been carried out in the presence of nonionic emulsifiers. For the type of emulsifiers and the quantity, see the international patent application WO 2006/122936 directed.

To the matrix

There should be a difference in refractive index between the matrix and the polymer particles. Preferably, the difference should be at least 0.01, more preferably at least 0.1. Both the matrix and the polymer particles can have the higher refractive index. The key is that there is a difference. This can already be estimated from the refractive indices of the monomers or isolated polymers (ie isolated cores or shells).

Ideally, the monomer composition of the core differs significantly in the shell. The core is preferably crosslinked while the shell is preferably uncrosslinked.

For the preparation of the emulsion polymer, the monomers of the shell can be metered in the polymerization in less than 90 minutes, particularly preferably in less than 60 minutes and in particular in less than 30 minutes. Most preferably, the polymerization of the monomers of the shell is carried out in batch - mode, ie all monomers of the shell are the polymerization as possible at the same time, generally within a few minutes, z. B. a maximum of 10 or a maximum of 5 minutes, fed and then polymerized. Before the beginning of the addition of the monomers of the shell, preferably more than 90% by weight of the total amount of initiator used for the emulsion polymerization has been added, and it is particularly preferred to use the entire amount of initiator used for the emulsion polymerization before the addition of the monomers of the shell. Methods of this kind are for example from WO 2006/122936 known.

The shell monomers may also contain crosslinking monomers. Crosslinking monomers are in particular monomers with two polymerizable groups, eg. B. with two vinyl groups or allyl groups. Mention may be divinylbenzene, alkanediol diacrylates or diallyl phthalate. Core / shell particles of this kind are used for example in the WO 2006/122936 described.

The proportion of crosslinking monomers in the monomer mixture of the cores in the case is preferably 0.5 to 25, more preferably 1 to 7% by weight, most preferably 2 to 6% by weight, based on the monomers of the cores. The proportion of crosslinking monomers in the monomer mixture of the shells is then preferably 0.01 to 10, particularly preferably 0.1 to 5% by weight, very particularly preferably 0.1 to 3 wt .-% based on the monomers of the shells.

The amount by weight of the crosslinking monomers of the core in the case is preferably at least twice as high as the amount by weight of the crosslinking monomers of the shell.

Besides previously mentioned polymers and other polymeric compounds, eg. As polycondensates or polyadducts conceivable. Called z. As polyesters, polyamides, formaldehyde resins such as melamine, urea or phenol-formaldehyde, polyepoxides, polyurethanes or the above polymers containing the main monomers listed, for. As polyacrylates, polybutadienes, styrene / butadiene copolymers.

The calculated according to Fox Tg of the monomer mixture of the shell is preferably -50 to 110 ° C, particularly preferably -40 to 25 ° C. Preferably, the core employs monomers having a glass transition temperature (Tg) above the film-forming temperature while the shell monomers have a Tg below the film-forming temperature to film. The Tg of the monomer mixture of the shell is preferably at least 10 ° C lower, more preferably at least 20 ° C lower than the Tg of the monomer mixture of the core.

Preferably, a transition stage is formed between the core and the shell.

The emulsion polymer with transition stage used is obtained by a multi-stage polymerization, wherein initially in at least a first stage, the monomers are polymerized forming the core, then the monomers in at least a second stage (transition stage) are polymerized and finally in a 3rd Stage the monomers are polymerized, which form the filmable shell. Preferably, the 2nd stage is crosslinked, it then forms together with the 1st stage the discrete polymer particles in the matrix. Systems with the structure core / transition stage / shell, for example, in the WO 04/098793 disclosed.

For the preparation of the effect or color and effect coating agent

The effect-imparting or color and effect coating composition is obtained according to the invention by filming an emulsion polymer having a core / shell structure. The shell of the emulsion polymer is filmable and forms the matrix, while the cores of the emulsion polymer are dispersed as discrete polymer particles in the matrix. The above statements on the particle size and particle size distribution of the discrete polymer particles (cores) also apply to the emulsion polymer (core / shell particles) themselves DE-A 19717879 and DE-A 19820302 described.

Preparation of discrete polymer particles

The preparation of the polymer particles or polymers takes place in a preferred embodiment by emulsion polymerization, it is therefore an emulsion polymer. The emulsion polymerization is particularly preferred because of the availability of polymer particles having a uniform spherical shape. However, the production can z. B. also be carried out by solution polymerization and subsequent dispersion in water.

In the emulsion polymerization, ionic and / or nonionic emulsifiers and / or protective colloids or stabilizers are used as surface-active compounds. A detailed description of suitable protective colloids can be found in Houben-Weyl, Methods of Organic Chemistry, Volume XIV / 1, Macromolecular Materials, Georg-Thieme-Verlag, Stuttgart, 1961, pp. 411-420 , Suitable emulsifiers are both anionic, cationic and nonionic emulsifiers. Emulsifiers are preferably used as surface-active substances whose molecular weight, in contrast to the Protective colloids are usually below 2000 g / mol. The surfactant is usually used in amounts of from 0.1 to 10% by weight, based on the monomers to be polymerized.

Water-soluble initiators for the emulsion polymerization are z. For example, ammonium and alkali metal salts of peroxodisulfuric, z. For example, sodium peroxodisulfate, hydrogen peroxide or organic peroxides, z. B. tert-butyl hydroperoxide. Also suitable are so-called reduction-oxidation (red-ox) initiator systems. The redox initiator systems consist of at least one mostly inorganic reducing agent and one inorganic or organic oxidizing agent. The oxidation component is z. B. to the above-mentioned initiators for emulsion polymerization. The reduction components are, for. B. to alkali metal salts of sulfurous acid, such as. For example, sodium sulfite, sodium hydrogen sulfite, alkali metal salts of the desulfurous acid such as sodium disulfite, bisulfite addition compounds aliphatic aldehydes and ketones, such as acetone bisulfite or reducing agents such as hydroxymethanesulfinic acid and salts thereof, or ascorbic acid. The red-ox initiator systems can be used with the concomitant use of soluble metal compounds whose metallic component can occur in multiple valence states.

Usual Red Ox initiator systems are z. As ascorbic acid / iron (II) sulfate / sodium peroxydisulfate, tert-butyl hydroperoxide / sodium disulfite, tert-butyl hydroperoxide / Na-hydroxymethanesulfinic acid. The individual components, eg. As the reduction component, may also be mixtures, for. B. a mixture of the sodium salt of hydroxymethanesulfinic acid and sodium disulfite. The amount of initiators is generally 0.1 to 10 wt .-%, preferably 0.5 to 5 wt .-%, based on the monomers to be polymerized. It is also possible to use a plurality of different initiators in the emulsion polymerization.

The emulsion polymerization is generally carried out at 30 to 130, preferably 50 to 90 ° C. The polymerization medium may consist of water only, as well as of mixtures of water and thus miscible liquids such as methanol. Preferably, only water is used. The emulsion polymerization can be carried out both as a batch process and in the form of a feed process, including stepwise or gradient mode. Preferably, the feed process in which one submits a portion of the polymerization, heated to the polymerization, polymerized and then the rest of the polymerization, usually over several spatially separate feeds, one or more of which monomers in pure or in emulsified form, continuously , gradually or with the addition of a concentration gradient while maintaining the polymerization of the polymerization zone supplies. In the polymerization can also z .B. For better adjustment of the particle size, a polymer seed can be provided.

The manner in which the initiator is added to the polymerization vessel in the course of the free radical aqueous emulsion polymerization is known to one of ordinary skill in the art. It can be introduced both completely into the polymerization vessel, or used continuously or in stages according to its consumption in the course of the free radical aqueous emulsion polymerization. In detail, this depends on the chemical nature of the initiator system as well as on the polymerization temperature. Preferably, a part is initially charged and the remainder supplied according to the consumption of the polymerization.

A uniform particle size distribution, d. H. a low polydispersity index is obtainable by means known to the person skilled in the art, e.g. Example by varying the amount of surface-active compound (emulsifier or protective colloids) and / or corresponding stirrer speeds.

The cores preferably have a particle diameter of 50 to 500 nm, more preferably 100 to 400 nm.

To remove the residual monomers is usually after the end of the actual emulsion polymerization, ie added after a conversion of the monomers of at least 95%, initiator. The individual components can be added to the reactor in the feed process from above, in the side or from below through the reactor bottom. In the emulsion polymerization aqueous dispersions of the polymer are generally obtained with solids contents of 15 to 75 wt .-%, preferably from 40 to 75 wt .-%.

Preparation of polymer particles / matrix

The core and shell of the particles can be chemically bonded together, for example by polymerization. A physical mixture of core and shell is also possible.

The data for core or shell of the previous chapter also refer to the cores or shells in core / shell particles.

The aqueous dispersion of the discrete polymer particles obtained in the emulsion polymerization may be mixed with the amount required to adjust the lattice structure (see core to shell weight ratio) of the polymeric compound and then the water removed. Due to the often high viscosity of the polymeric compound, it may be advantageous to first mix the polymer particles with the structural components of the polymeric compound and then, after the dispersion of the polymer particles, these structural components z. B. by condensation or adduct formation to implement the polymeric compounds.

Emulsion polymers as discrete polymer particles and emulsion polymers as matrix

The corresponding emulsion polymers can simply be mixed and then the water removed. Insofar as the emulsion polymers for the matrix have a glass transition temperature (Tg) below 20 ° C (see above), the polymer particles film at room temperature and form the continuous matrix, at higher Tg heating to temperatures above the Tg is required.

Core / shell particles

It is particularly simple and advantageous to prepare both emulsion polymers in one step as a core / shell polymer. This is the Emulsion polymerization carried out in two stages. First, the monomers are polymerized, which form the core (= later discrete polymer particles), then the monomers are polymerized in a second stage in the presence of the core, which form the shell (= later matrix). In the shell, preferably no crosslinking monomers or other crosslinkers are used. The shell is therefore preferably not crosslinked. The core is preferably crosslinked.

In this case, the monomer mixture of the shell to be coated is particularly preferably chosen such that the glass transition temperature of the shell (calculated according to the Fox equation) is lower than that of the core.

After complete or partial volatilization of the liquid phase (eg, water), the matrix is formed from the shell by filming and the discrete polymer particles are distributed from the remaining nuclei of core / shell particles dispersed in the matrix.

The coating agent causes an optical effect, that is, a reflection to be observed by interference of the light scattered on the polymer particles. The effect may be, for example, a color change or a visible pearl effect as a function of the viewing angle. The color change and its expression is also dependent on the color of the lying under the effect or color and effect coating agent layer. The wavelength of the reflection can be depending on the distance of the polymer particles in the entire electromagnetic spectrum. The wavelength is preferably in the UV range, IR range and in particular in the range of visible light. The wavelength of the reflection to be observed depends on the known Bragg equation of the interplanar spacing, here the distance between the polymer particles arranged in a space lattice structure in the matrix.

In order to set the desired space lattice structure with the desired distance between the polymer particles, in particular the weight proportion of the matrix is to be selected accordingly. In the preparation methods described above, the organic compounds, for. B. polymeric compounds are used in an appropriate amount. The weight percentage of In particular, the matrix, ie the weight fraction of the filming shell, is dimensioned such that a space lattice structure of the polymer particles is formed, which reflects electromagnetic radiation in the desired area.

The weight ratio of core to shell is preferably 1: 0.05 to 1:20, more preferably 1: 0.1 to 1:10.

The distance between the polymer particles (each to the center of the particles) may be 0.5 to 10 microns. Suitably, the distance is 50 to 1100 nm, so that electromagnetic radiation is reflected in the range of ultraviolet to near-infrared light. Advantageously, the distance is 100 to 500 nm when an effect, i. a reflection in the range of visible light is desired.

The spacing of the polymer particles may be affected by mechanical compression or stretching of the applied and dried coating material. As a result, the cores are brought closer to each other or further apart, whereby the visible wavelength is shorter or longer. These deformations can be plastic or elastic.

The effecting or color and effect coating agent can be applied to substrates to which a filler and / or basecoat has already been applied. Any commercially available filler or basecoat can be used. As basecoat, an aqueous basecoat is advantageous.

It is advantageous to apply a transparent polymer layer to the layer of the already applied effect-imparting or color and effect coating agent. Particularly advantageous is the transparent polymer layer on the coating agent, which was applied by a sputtering process. Very particularly advantageous is the transparent polymer layer on the coating agent, which was applied by a sputtering process.

The brilliance and stability of this optical effect can be improved by the application of a transparent polymer layer and can serve as a topcoat layer. A transparent polymer layer can be applied to the effecting or color and effect coating agent in order to improve color brilliance and stability in the coating agent. This is for example in the DE-A-10321079 described.

The polymer in the transparent layer may be any polymer. It is possible to use polycondensates, polyadducts or polymers obtainable from free-radically polymerizable compounds (monomers). The latter are preferred.

The polymer of the transparent layer is preferably at least 40% by weight, preferably at least 60% by weight, of so-called main monomers selected from C ₁ to C ₂₀ alkyl (meth) acrylates, vinyl esters of carboxylic acids containing up to 20 C atoms, Vinylaromatics with up to 20 carbon atoms, ethylenically unsaturated nitriles, vinyl halides, vinyl ethers containing 1 to 10 C atoms alcohols, aliphatic hydrocarbons having 2 to 8 C atoms and one or two double bonds or mixtures of these monomers constructed.

The polymer of the transparent polymer layer is particularly preferably an emulsion polymer. The preparation of the emulsion polymers is described above.

Preferably, the average particle diameter in the aqueous polymer dispersion obtained by emulsion polymerization is between 10 and 500 nm, preferably between 30 and 200 nm. These are filmed in the applied layer, so that the layer is transparent.

The transparent polymer layer is not effective in contrast to the underlying effect or effect and coloring layer.

To produce the transparent polymer layer, the polymer, preferably in the form of a dispersion or solution, on the effect or color and effect-imparting coating applied. In the case of a dispersion or solution, drying takes place, if appropriate also at elevated temperature. Preferably, the layer is dried at 100 to 160 ° C in a time of 10 to 30 minutes. The resulting transparent polymer layer preferably has a thickness of from 0.2 to 500 μm, preferably from 1 to 200 μm, more preferably from 1 to 100 μm and in particular from 2 to 50 μm. The transparent polymer layer improves the brilliance of the color with stability of the color effects.

As a polymer for a transparent polymer layer, any commercial clearcoat can be used. Solvent-containing clearcoats advantageously contain little to no high-boiling organic solvent. Particularly advantageous are aqueous clearcoats. Very particularly advantageous are two-component clearcoats. In particular, clearcoats are suitable which are curable thermally and with actinic radiation (so-called "dual-cure" clearcoats). These clearcoats are described, for example, in the patent applications DE-A-10143414 and DE-A-10143383 described. They are offered for example by BASF Coatings AG under the name TwinGloss®.

The transparent polymer layer and the basecoat layer are applied by means of the application methods mentioned above. The sputtering process and the ink-jet process are preferably used, and the sputtering process without electrostatic coating coating, in particular the spray coating process, is most preferably used as sputtering process.

The transparent polymer can be applied when the effecting or color and effect coating agent is partially or completely dried. Preferably, the transparent polymer is applied after complete drying of the coating agent.

The effecting or color and effect coating agent may contain further colorants. It may be in the continuous phase, in the core material and / or in the shell material, but preferably for the most part in the continuous phase or in the core. Suitable colorants are finely divided organic or inorganic pigments, finely divided disperse dyes or dyes soluble in the continuous phase. Preference is given to soluble dyes.

Preferably, the colorant is a water-soluble dye, especially one from the group of acidic or basic dyes or a sulfur dye. Particular preference is given to those water-soluble dyes whose water solubility is based on sulfonic acid groups or sulfuric acid ester groups present in the molecule. Examples of suitable colorants include in DE-A 19834194 described.

Suitable colorants are also combinations of two or more dyestuff individuals, preferably from one and the same class. In particular, this applies to brown and black dye settings. For example, commercially available commercial dyes include Lurazol Black DFN, Lurazol Braun N3G, Lurazol Violet NR and Lurazol BN.

For the colorant additive amounts, it is expedient to add only enough colorant to adequately attenuate a background color of the effect layers which is particularly noticeable under acute viewing angles. The minimum amount is lower when the shell material is soft and when the shell portion is high. Conversely, if the shell material is hard and the shell content of the core / shell particles is low, one needs a slightly higher dye addition.

The optimal amount of the dye which is added to the dispersion of the core / shell particles, on the one hand to cover the background color well, but on the other hand not to interfere with the interference colors can be determined by some targeted preliminary tests, as in the embodiments of the DE-A 19834194 shown, easily determined.

The effecting or color and effect coating agent and / or the transparent polymer layer may contain auxiliaries and / or additives. Examples of such auxiliaries and / or additives are leveling agents, adhesives, release agents, plasticizers, application aids, viscosity modifiers, Film forming aids or fillers. It is also possible to add coloring additives, such as, for example, organic dyes or organic or inorganic pigments which are soluble in water or organic media, and also, if appropriate, radicals of organic or inorganic solvents, dispersants or dye additives. These can give the effect-giving or color and effect coating agents a natural color, which is superimposed by the interference effect.

Preferably, the effecting or color and effect coating composition contains associative thickener as an auxiliary or additive. These contribute particularly effectively to droplet formation in the spray process. Associative thickeners are characterized in the dissolved, highly viscous form by high transparency or transparency and are suitable for. B. as a thickener or rheology modifier.

Associative thickeners are water-soluble polymers and have surfactant-like hydrophobic constituents which are able to associate, ie interact, in themselves in a hydrophilic, in particular aqueous medium, both with themselves and with other hydrophobic substances. The resulting associative network thickens or gels the medium. Suitable associative thickeners are described, for example, in the publications EP-A 0013836 . WO 99/65958 and WO 2006/016035 described.

A further improvement in the color brilliance and the stability of the effecting or color and effect coating agent can be achieved by heating the effecting or color and effect coating agent after application to temperatures above 60 ° C. This can advantageously take place together with an optionally applied transparent polymer layer. The temperature is preferably above the glass transition temperature of the matrix. Preferably, the temperature is above 100 ° C. It generally does not exceed 200 ° C. The temperatures are based on the environment. The heating preferably lasts at least 5 seconds and a maximum of 5 minutes. Methods of this kind are for example in the WO 04/099330 described.

In a particular embodiment of the method according to the invention, the effecting or color and effect coating agent is applied in a layer thickness of 1 to 200 .mu.m by means of spray coating process, wherein the coating agent is an emulsion polymer having a single particle species and a core / shell ratio in a Range from core to shell of 1: 0.1 to 1:10. Advantageously, the particle diameter of the core / shell particles having a polydispersity index below 0.3 is in a range of 100 to 500 nm.

In a further particular embodiment of the method according to the invention, after the single application, i. H. the application in one step, the effect or color and effect coating agent applied a transparent polymer layer over the dried effect or color and effect coating agent.

The effect finishes obtained by the process according to the invention can be used for coating as or in coating compositions. According to the invention they are used for coating of bodies and body parts made of metal.

The method can also be used according to the invention for carriers, such as those in WO 2007/096291 to be discribed. The carrier may be made of any material. In consideration come z. As carriers made of paper or plastic films, in particular, it may be in the carrier also a multi-layer laminate whose individual layers consist of different materials. The thickness of the polymer layer applied to the carrier may be arbitrary, but in order to achieve good effects of sufficient intensity, a thickness of 1 μm to 150 μm is generally sufficient, but may also have a thickness of up to several millimeters, e.g. B. up to 5 mm or more, preferably not more than 2 mm.

It is essential that the coated carrier after WO 2007/096291 overall so little elastic that when the mechanical stress ceases, the wavelength of the Bragg reflection remains changed with respect to the initial state. This can be z. B. be achieved in that the matrix material is chosen so that the restoring forces are small. This can z. B. can be achieved by concomitant use of regulators in the polymerization of the shell of core / shell particles, the regulator amount is preferably less than 10, more preferably less than 2 parts by weight per 100 parts by weight of monomers. In particular, this can also be achieved by using only little or no crosslinking monomers or other crosslinkers in the matrix or in the shell of the core / shell particles.

This can also be achieved in that the carrier is less elastic than the effecting or color and effect coating agent; Naturally, the coated coating material can only go as far back to its original state when adhering to the carrier material as the carrier material itself.

Furthermore, the process can be used for effect paint-on-change color to indicate the state of tension of hygienic or medical articles attached to the body. Articles of this kind are for example in the WO 2007/096272 described. These methods are interesting for the automotive refinish area.

The invention further relates to multicoat paint systems obtainable by the process according to the invention. According to the invention, the multicoat system is applied to bodies and body parts made of metal.

In the following the invention will be further explained with reference to examples.

Examples

All syntheses were performed in a 2000 ml four-necked flask equipped with a reflux condenser, a nitrogen inlet tube, monomer emulsion feed tubes and initiator solution, and an anchor stirrer at a speed of 150 rpm.

The particle size distribution was determined by the HDF method with the PSDA Particle Size Distribution Analyzer (parameter see above) and from this the D ₁₀ , D ₅₀ and D ₉₀ values were taken and the polydispersity index was determined.

Example 1: Synthesis of a Core Particle Dispersion

In a reactor with anchor stirrer, thermometer, gas inlet tube, feed tubes and reflux condenser initially 258.6 g of water were initially charged, then 5.08 g Polystyrenkeimpartikeldispersion were added with a particle size of 30 nm and a solids content of 33% by mass. The flask contents were then heated and stirred at a speed of 150 min ^-1 . During this time, nitrogen was fed to the reactor. Upon reaching a temperature of 85 ° C in the heat bath and 80 ° C in the reactor, the nitrogen supply was adjusted and avoided that air came into the reactor. Before the polymerization, 19.3% of a sodium persulfate solution of 3.6 g of sodium persulfate in 100 g of water was added to the reactor and preoxidized for 5 minutes, then the remainder of the sodium persulfate solution was added over 4 hours. During these 4 hours, 8.6% by weight of monomer emulsion (a), 5.22 g of Texapon NSO® (sodium lauryl ether sulfate from Cognis, conc .: 28% by mass) and 35.0 g of n-butyl acrylate were within 40 Minutes added. Subsequently, the remainder of the monomer emulsion (a) was added over a period of 3 hours and 20 minutes. It was assumed that the reaction proceeds in the deficiency regime, so that the formation of secondary germs is avoided. After completion of the monomer addition, the dispersion was postpolymerized for one hour. The mixture was then cooled to room temperature. Monomer emulsion (a) 540.0 g styrene 13.33 g divinylbenzene 1.67 g allyl methacrylate 10.0 g acrylic acid 16.39 g Texapon, mass concentration: 28% 22.11 g Caustic soda, mass concentration: 25% 501.3 g water

The dispersion has the following properties: Solids content d. Polymers: 40% by mass (calculated) particle size: 206.3 nm coagulation: <1.5 g PH value: 6.59 polydispersity: 0.14

The coagulation is determined by filtration of the dispersion through a plastic filter (mesh size 50 μm), followed by drying of the filter residue and weighing.

The preservation of core particles of different sizes is possible by changing the germ particle concentrations. Table 1 shows different particles. Table 1 Example no. 1A 1B 1C 1D 1E 1F Keimkonz. % 0.65 0.55 0.44 0,275 0.2 0.17 Solids content 35.0 35.4 40.2 39.9 30.0 34.8 Particle size (nm) 149.1 161.5 170.6 206.3 208.6 254.8 PI 0.13 0.16 0.17 0.14 0.26 0.14

Example 2 Synthesis of a Core-Shell Particle Dispersion (Green Film)

In a reactor with anchor stirrer, thermometer, gas inlet tube, feed tubes and reflux condenser, 325.8 g dispersion according to Example 1D were submitted. Was then begun heating, and stirring at a speed of 150 min ^-1. During this time, nitrogen was fed to the reactor. Upon reaching a temperature of 85 ° C in the heat bath and 80 ° C in the reactor the nitrogen supply was stopped and air was prevented from entering the reactor. 9.8% of a sodium persulfate solution of 0.8 g of sodium persulfate in 50 g of water (initiator solution) was added prior to polymerization. After 5 minutes, the remainder of the sodium persulfate solution was added over 3 hours. During the same 3 hours, the monomer emulsion (a) was added over 45 minutes, followed by postpolymerization for 15 minutes. Then, the monomer emulsion (b) was added within 2 hours and cooled to room temperature after further postpolymerization. Monomer emulsion (a) (2nd stage) 11.7 g styrene 9.1 g n-butyl acrylate 1.17 g allyl methacrylate 1.46 g acrylic acid 1.86 g Texapon NSO, mass concentration: 28% 1.46 g Caustic soda, mass concentration: 25% 55.0 g water 71,5g n-butyl acrylate 34.6 g methyl methacrylate 1.3 g acrylic acid 1.16 g Texapon, mass concentration: 28% 0.77 g Caustic soda, mass concentration: 25% 53.5 g water

The dispersion has the following properties: Mass ratio core: shell: 1: 1 (calculated) Solids content d. Polymers: 40% by mass (calculated) particle size: 279.8 nm coagulation: <2 g PH value: 5.66 polydispersity: 0.15

Core-shell particles with a core: shell mass ratio of 1: 1 can be produced. Table 1 shows the properties of core-shell particles and the films made from the dispersions. Table 2 Example no. 2A 2 B 2C 2D 2E 2F Core number 1A 1B 1C 1D 1E 1F Solids content 40.2 40.3 40.2 40.8 40.0 39.9 Particle size (nm) 234.2 224.0 233.7 279.8 364.7 332.6 PI 0.19 0.17 0.16 0.15 0.26 0.13 Film color (p) black violet violet blue green orange red Film color (s) black black violet black blue Light Blue blue green green

In this table, film color is understood to mean the color impression which is recorded in the case of vertical (p) or when viewed at an acute angle (s) of 10 °.

All syntheses were carried out in a 4000 ml cervical vessel equipped with a reflux condenser, a nitrogen inlet tube, monomer emulsion feed tubes and initiator solution, and an anchor stirrer at a speed of 150 rpm.

Example 3 Production of Filmable About 380 nm Particles (Red Film)

In a reactor with anchor stirrer, thermometer, gas inlet tube, feed tubes and reflux condenser initially 397.28 g of water were initially charged, then 1.42 g Polystyrenkeimpartikeldispersion were added with a particle size of 30 nm and a solids content of 33% by mass. The flask contents were then heated and stirred at a speed of 150 min ^-1 . During this time, nitrogen was fed to the reactor. Upon reaching a temperature of 75 ° C, the nitrogen supply was adjusted and avoided that air came into the reactor. Prior to polymerization, 20% of a sodium peroxodisulfate solution of 3.5 g of sodium persulfate in 46.5 g of water was added to the reactor and preoxidized for 5 minutes, then the remainder of the sodium persulfate solution was added over 4.5 hours. At the same time monomer emulsion a) of the core was added for 2 hours, then polymerized for 30 minutes and finally monomer emulsion b) added to the dish over 2 hours. After 1.5 hours during the feed of the monomer emulsion b) feed 4 was added to the monomer emulsion b). After completion of the monomer addition, the dispersion was postpolymerized for one hour. The mixture was then cooled to room temperature.

The composition of the feeds was as follows: Feed 1: monomer emulsion a) 116.67 g water 8.75 g Texapon NSO, mass concentration: 28% in water 0.7 g Caustic soda, mass concentration: 25% in water 14.0 g acrylic acid 14.00 g diallyl phthalate 168.0 g styrene 168.00 g n-butyl acrylate 7.00 g dishwater 50 g Sodium peroxodisulfate, mass conc. 7% in water 116.67 g water 8.75 g Texapon NSO, mass concentration: 28% in water 0.7 g Caustic soda, mass concentration: 25% in water 7.0 g acrylic acid 3.5 g Dialiylphthalat 63.00 g methyl methacrylate 273.00 g n-butyl acrylate 7.00 g dishwater 7.00 g acrylic acid 6.00 g water

The dispersion has the following properties: Mass ratio core: shell: 1: 1 (calculated) Solids content d. Polymers: 50.4% (calculated) particle size: 381 nm coagulation: 2 g PH value: 3.2 PI: 0.130

Example 4 Production of Filmable About 340 nm Particles (Green Film)

In a reactor with anchor stirrer, thermometer, gas inlet tube, feed tubes and reflux condenser initially 877.88 g of water were initially charged, then 4.91 g Polystyrenkeimpartikeldispersion were added with a particle size of 30 nm and a solids content of 33% by mass. The flask contents were then heated and stirred at a speed of 150 min ^-1 . During this time, nitrogen was fed to the reactor. When reaching a temperature of 75 ° C, the nitrogen supply was stopped and avoided that air came into the reactor. Prior to polymerization, 20% of a sodium peroxodisulfate solution of 12.75 g of sodium persulfate in 169.39 g of water was added to the reactor and preoxidized for 5 minutes, then the remainder of the sodium persulfate solution was added over 4.5 hours. At the same time monomer emulsion a) of the core was added for 2 hours, then polymerized for 30 minutes and finally monomer emulsion b) added to the dish over 2 hours. After 1.5 hours during the feed of the monomer emulsion b) feed 4 was added to the monomer emulsion b). After completion of the monomer addition, the dispersion was postpolymerized for one hour. The mixture was then cooled to room temperature.

The composition of the feeds was as follows: Feed 1: monomer emulsion 283.33 g water 21.25 g Texapon NSO, mass concentration: 28% in water 1.70 g Caustic soda, mass concentration: 25% in water 34.0 g acrylic acid 34.0 g diallyl phthalate 408.0 g styrene 408.0 g n-butyl acrylate 17.0 g dishwater 182.14 g Sodium peroxodisulfate, mass conc. 7% in water 283.33 g water 21.25 g Texapon NSO, mass concentration: 28% in water 1.7 g Caustic soda, mass concentration: 25% in water 17.0 g acrylic acid 8.5 g diallyl phthalate 153.0 g methyl methacrylate 663.0 g n-butyl acrylate 17.0 g dishwater 17.0 g acrylic acid 16.0 g water

The dispersion has the following properties: Mass ratio core: coat: 1: 1 (calculated) Solids content d. Polymers: 50.7% (calculated) particle size: 339 nm coagulation: 2g PH value: 3.2 polydispersity: 0,139

Claims (21)

1. Process for producing effect paint systems on vehicle bodies and bodywork parts of metal, characterized in that an effect-imparting or colour- and effect-imparting coating material which consists of a matrix and discrete polymer particles,
   wherein after full or partial volatilization of the liquid phase, the matrix composed of the shell is formed by filming and the discrete polymer particles composed of the remaining cores of core/shell particles are arranged in distribution in the matrix, characterized in that the coating material is applied in a single operation by an atomizing process and then is completely or partially dried by full or partial volatilization of the liquid phase.
2. Process according to Claim 1, characterized in that spray painting processes without electrostatic paint charging are the atomization process.
3. Process according to Claim 2, characterized in that the spray painting process without electrostatic paint charging is a spray coating operation.
4. Process according to any of Claims 1 to 3, characterized in that the coating material is applied in a film thickness of 0.2 to 500 µm.
5. Process according to any of Claims 1 to 4, characterized in that the coating material comprises a transition stage between shell and core.
6. Process according to any of Claims 1 to 5, characterized in that the coating material after application is heated to temperatures above 60°C.
7. Process according to any of Claims 1 to 6, characterized in that the polymer particles have a mean particle diameter in the range from 50 nm to 10 µm.
8. Process according to any of Claims 1 to 6, characterized in that the polymer particles are one or more particle varieties having a mean particle diameter in the range from 0.05 to 10 µm, wherein each particle variety has a polydispersity index (P.I.) of less than 0.6, calculated according to the formula $$\mathrm{P}.\mathrm{I}.=\left(\mathrm{D}90-\mathrm{D}10\right)/\mathrm{D}50$$

   

   in which D90, D10 and D50 designate particle diameters as follows:

   D90: 90 wt% of the total mass of all particles have a particle diameter less than or equal to D90

   D50: 50 wt% of the total mass of all particles have a particle diameter less than or equal to D50

   D10: 10 wt% of the total mass of all particles have a particle diameter less than or equal to D10.
9. Process according to any of Claims 1 to 8, characterized in that the coating material is composed overall to an extent of at least 40 wt% of principal monomers selected from C1 to C20 alkyl (meth)acrylates, vinyl esters of carboxylic acids containing up to 20 carbon atoms, vinylaromatics having up to 20 carbon atoms, ethylenically unsaturated nitriles, vinyl halides, vinyl ethers of alcohols containing 1 to 10 carbon atoms, aliphatic hydrocarbons having 2 to 8 carbon atoms and one or two double bonds, or mixtures of these monomers.
10. Process according to any of Claims 1 to 9, characterized in that the polymer particles of the coating material and the matrix differ in refractive index.
11. Process according to any of Claims 1 to 10, characterized in that in the coating material the weight ratio of the monomers which form the core to the monomers which form the shell is 1:0.05 to 1:20.
12. Process according to any of Claims 1 to 11, characterized in that the coating material is applied to a basecoat film.
13. Process according to any of Claims 1 to 12, characterized in that a transparent polymer layer is applied to the applied coating material.
14. Process according to Claim 13, characterized in that the polymer of the transparent layer is an aqueous clearcoat material.
15. Process according to Claim 13 or 14, characterized in that the polymer in the transparent layer is applied in the form of a solution or dispersion to the applied coating material and then drying takes place.
16. Process according to any of Claims 13 to 15, characterized in that the thickness of the transparent layer is 0.2 to 500 µm.
17. Process according to any of Claims 13 to 16, characterized in that the transparent polymer layer is applied by atomizing processes.
18. Process according to any of Claims 1 to 17, characterized in that the coating material and/or the transparent polymer layer comprise auxiliaries and/or adjuvants.
19. Use of effect paint systems according to any of Claims 1 to 18 for coating as or in coating materials.
20. Use of effect paint systems according to Claim 19 for coating metals, especially vehicle bodies and bodywork parts.
21. Multi-coat paint system obtainable by a process of Claims 1 to 18.