DE4432260C1 - Scratch-resistant, acid-resistant top-coat material - Google Patents

Abstract

Coating materials (I) contain binder (II), normal paint additives and solvent. Binder (II) is based on: (A) 20-60 wt.% OH gp.-contg. (meth)acrylate copolymer(s); (B) 0-60 wt.% OH-functional polyester(s) obtd. by reacting (b1) 10-30 mole% glycidyl ester(s) of alpha, alpha-dialkyl-substd. aliphatic monocarboxylic acids, (b2) 30-50 mole% below 16C (cyclo)aliphatic polycarboxylic acid(s) or anhydride(s), (B3) 5-20 mole% 2,2-dialkyl-alkanediol(s), (b4) 5-20 mole% polyol(s) with at least one sec. OH gp., (b5) 5-15 mole% hydroxy-carboxylic acid(s) with at least one OH gp. and at least one COOH gp.; (C) 5-50 wt.% OH-functional siloxane-polyester(s) obtd. by reacting (c1) 15-30 mole% ester (b1) as above, (c2) 35-50 mole% polyacid (b2) as above, (c3) 8-20 mole% diol (b3) as above, (c4) 10-20 mole% polyol (b4) as above, (c5) 5-15 mole% hydroxy-acid (b5) as above and (c6) 1-5 mole% alpha,omega-hydroxy-, -carboxy- and/or -epoxy-functional polysiloxane(s), with the terminal functional gps. linked to Si via an alkylene gp.; and (D) crosslinker(s), i.e. opt. blocked di- and/or poly-isocyanate(s) and/or amino resin(s). Also claimed is a multi-coat painting process (pref. for cars) comprising: (a) applying a base-coat to an opt. precoated substrate and then overcoating with a transparent topcoat (I), either after drying or wet-in-wet; or (b) applying a pigmented topcoat (I) to an opt. precoated substrate.

Description

The invention relates to coating agents, in particular for transparent but also pigmented multi-layer coatings, are suitable, for example, in the car series painting due to its high resistance to "acid rain" high resistance (scratch resistance), for example against cleaning brushes in car washes, and one high processing solids.

EP-A-02 17 364 describes lacquers and molding compositions with anti-adhesive Properties that are used particularly advantageously where Surfaces, e.g. B. building facades from pollution (so-called Graffity soiling) protected or from such soiling can be easily cleaned again. Such paints can in the Automotive painting cannot be applied because of a Touch-up paint does not adhere to it.

DE-A-40 17 075 relates to top coats for painting Automobile bodies. To improve resistance to mechanical loads caused by the car wash Cleaning brushes are created and to improve the acid resistance contain these coating agents with functional groups, e.g. B. Hydroxyl-equipped oligomeric polysiloxanes, which are in the Separate spray application from the remaining binder matrix and deposit in the interface. However, it has been shown that the good scratch resistance of the films is gradually lost, which increases leads to an extremely poor long-term effect. The surfaces of the coatings obtained tend to crater. Touch-up paint adhere badly to it.

The object of the present invention is therefore to provide coating agents for transparent top layers of multi-layer coatings and pigmented Top layers, especially for automotive OEM painting, to provide both a high processing solids have, as well as coatings with permanent scratch resistance and high acid resistance, especially an improved one Resistance to sulfuric acid.

It has been shown that the demand for chemical resistant, especially sulfuric acid-resistant and permanently scratch-resistant Coating agents can be fulfilled by coating agents that represent an object of the invention and are based on hydroxy-functional (meth) acrylic copolymers and crosslinking agents and can contain additives and solvents commonly used in paint. you are characterized in that they contain binders based from:

• A) 20 to 60 wt .-% of one or more hydroxyl groups ger (meth) acrylic copolymers,
• B) 0 to 60% by weight, preferably over 20% by weight, of one or more hydroxyl-functional polyesters, obtainable by reaction of,
  • b1) 10 to 30 mol% of one or more glycidyl esters alpha, alpha-dialkyl-substituted saturated monocarboxylic acids,
  • b2) 30 to 50 mol% of one or more aliphatic and / or cycloaliphatic polycarboxylic acids with less than 16 carbon atoms or their anhydrides,
  • b3) 5 to 20 mol% of one or more 2,2-dialkyl alkanediols,
  • b4) 5 to 20 mol% of one or more polyols with at least one secondary OH group in the molecule,
  • b5) 5 to 15 mol% of one or more hydroxycarboxylic acids with at least one hydroxyl group and at least one carboxyl group in the molecule,

the sum of the mol% b1) to b5) adding up to 100 mol%,

• C) 5 to 50 wt .-% of one or more hydroxyl-functional siloxane polyesters obtainable by reaction of
  • c1) 15 to 30 mol% of one or more glycidyl esters alpha, alpha-dialkyl-substituted aliphatic monocarboxylic acids,
  • c2) 35 to 50 mol% of one or more aliphatic and / or cycloaliphatic polycarboxylic acids with less than 16 carbon atoms or their anhydrides,
  • c3) 8 to 20 mol% of one or more 2,2-dialkylalkane diols,
  • c4) 10 to 20 mol% of one or more polyols with at least one secondary OH group in the molecule,
  • c5) 5 to 15 mol% of one or more hydroxycarboxylic acids with at least one hydroxyl group and at least one carboxyl group in the molecule,
  • c6) 1 to 5 mol% of one or more alpha, omega-hydroxy, carboxy and / or epoxy functional polysiloxanes, the hydroxyl, carboxy and / or epoxy groups being terminally bonded directly to silicon via an alkylene group,

the sum of the mol% c1) to c6) being added to 100 mol%, and the sum of the wt .-% of components A) to C) each increase 100% by weight supplemented, and

• D) one or more crosslinking agents of the di- and / or polyisocyanate type, which can be blocked, and / or aminoplast resin.

The preparation of those contained in the coating composition according to the invention (Meth) acrylic copolymers (component A) can, for example, by Polymerization by conventional methods, e.g. B. the substance, solution or bead polymerization can be carried out. The different Polymerization processes are well known and are used, for example described in Houben-Weyl, Methods of Organic Chemistry, 4th ed., Volume 14/1, pp. 24-255 (1961).

The solution polymerization process is used to manufacture the coating agents used according to the invention (meth) acrylic Copolymers preferred. In this process, the solvent is in submitted the reaction vessel, heated to boiling temperature and Monomer / initiator mixture continuously in a certain time added. Solution polymerization can also be carried out in this way be that the addition of the monomers is delayed, d. H. alternating or in succession.

The polymerization is carried out, for example, at temperatures between 60 ° C and 160 ° C, preferably at 80 ° C to 140 ° C.

The polymerization reaction can be carried out with known ones Polymerization initiators are started. Suitable initiators are Common per and azo compounds that are in a first order reaction  decay thermally into radicals. The type and amount of initiator become like this chosen that at the polymerization temperature during the feed phase radical supply is as constant as possible.

Examples of preferred initiators for the polymerization are: dialkyl peroxides, such as di-tert-butyl peroxide, di-cumyl peroxide; Diacyl peroxides such as di-benzoyl peroxide, di-lauroyl peroxide; Hydroperoxides, such as cumene hydroperoxide, tert-butyl hydroperoxide; Peresters, such as tert-butyl perbenzoate, tert-butyl perpivalate, tert.- Butyl per-3,5,5-trimethylhexanoate, tert-butyl per-2-ethylhexanoate; Peroxydicarbonates, such as di-2-ethylhexyl peroxydicarbonate, dicyclo-hexyl peroxydicarbonate; Perketals such as 1,1-bis- (tert-butylperoxy) -3,5,5- trimethylcyclohexane, 1,1-bis (tert-butylperoxy) cyclohexane; Ketone peroxides such as cyclohexanone peroxide, methyl isobutyl ketone peroxide; Azo compounds such as 2,2'-azo-bis (2,4-dimethylvaleronitrile), 2,2'-azo bis (2-methylbutyronitrile), 1,1'-azo-bis-cyclohexane carbonitrile, azo-bis- isobutyronitrile.

The polymerization initiators, especially the peresters, are preferably in an amount of 0.2 to 5% by weight on the monomer Weighed, used.

As an organic solvent, which is conveniently in the Solution polymerization and later also in the invention Coating agents are used, for example, are suitable Glycol ethers such as ethylene glycol dimethyl ether; Glycol ether esters, such as Ethyl glycol acetate, butyl glycol acetate, 3-methoxy-n-butyl acetate, Butyl diglycol acetate, methoxypropyl acetate, esters such as butyl acetate, Isobutyl acetate, amyl acetate; Ketones, such as methyl ethyl ketone, Methyl isobutyl ketone, diisobutyl ketone, cyclohexanone, isophorone; Alcohols such as methanol, ethanol, propanol, butanol; aromatic Hydrocarbons such as xylene, Solvesso 100 (registered Trademark) and aliphatic hydrocarbons can also especially in the blend with the above-mentioned solvents be used.

To regulate the molecular weight, the  preferred solution polymerization common chain transfer agents used become. Examples are functionalized or non-functionalized Mercaptans, such as mercaptoethanol, n-octyl mercaptan, Thioglycolic acid esters, chlorinated hydrocarbons, cumene, dimeric alpha- Methylstyrene.

The polymerization conditions (reaction temperature, feed time of the Monomer mixture, solution concentration) are set up so that the (meth) acrylic copolymers for the prepared according to the invention Coating agent preferably a weight average molecular weight (Mw) (determined by gel permeation chromatography using polystyrene as Calibration substance) between 2000 and 20,000.

The hydroxyl-containing (meth) acrylic copolymers of Coating agents produced according to the invention are preferably in one Glass transition temperature range from -20 ° C to + 80 ° C, calculated from the glass transition temperatures given in the literature Homopolymers of the individual monomers (FOX equation, see e.g. Polymeric materials, Batzer, 1985, page 307).

Alkyl monomers of acrylic acid or methacrylic acid are preferably used as the monomer component for the preparation of the (meth) acrylic copolymers containing hydroxyl groups (component A). (Meth) acrylic here means acrylic and / or methacrylic. Examples for this are:
Methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, isopropyl methacrylate, tert-butyl acrylate, n-butyl acrylate, n-butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, cyclohexyl methacrylate, trimethylcyclohexyl methacrylate, 2- ethylhexyl acrylate, 2-ethylhexyl methacrylate, lauryl acrylate, lauryl methacrylate, stearyl acrylate, stearyl methacrylate, isobornyl acrylate, isobornyl methacrylate ; Hydroxyalkyl esters of acrylic acid or methacrylic acid, such as beta-hydroxyethyl acrylate, beta-hydroxyethyl methacrylate, beta-hydroxypropyl acrylate, beta-hydroxypropyl methacrylate, butanediol-1,4-monoacrylate, butanediol-1,4-monomethacrylate, hexanediol 1,6-monoacrylate, hexanediol-1, 6-monomethacrylate.

But it can also, at least in part, polyalkylene oxide mono- (meth) - acrylates with 2 to 10 alkylene oxide units per molecule become.

In addition, reaction products of hydroxyalkyl (meth) acrylates can also be used epsilon-caprolactone can be used.

Hydroxy-functional monomers, such as. B. Hydroxyalkyl esters of acrylic acid or methacrylic acid are polymerized in such amounts that for component A) preferably an OH number of 30 to 200 mg KOH / g results.

To equip the (meth) acrylic copolymer with carboxyl groups unsaturated acids can be polymerized in, for example (Meth) acrylic acid, maleic acid, fumaric acid and their half esters. she are polymerized in such amounts that component A) preferably an acid number of 1 to 50 mg KOH / g results.

Comonomers can also be used to prepare the copolymers that differ from the (meth) acrylic monomers. For example, vinyl monomers such as vinyl aromatics, e.g. B. Styrene, vinyl toluene, p-methyl styrene and p-tertiary butyl styrene; Vinyl ethers such as isobutyl vinyl ether; Vinyl esters, such as vinyl acetate, Vinyl propionate, vinyl benzoate, p-tert-butyl vinyl benzoate and Vinyl neodecanoate. The comonomers can be used in amounts of up to 50% by weight, for example 10 to 50% by weight, preferably 10 to 30% by weight, each based on the weight of the total monomers.

Proportionally polyunsaturated monomers can also be used be, e.g. B. divinylbenzene, ethylene glycol di (meth) acrylate, Butanediol di (meth) acrylate. Such monomers are used in small quantities admitted, d. H. in such quantities that the products obtained are not gel.

Those preferably additionally used as component B) Hydroxy-functional polyesters are polycondensation products from components b1) to b5). Such polyesters are used in the  Usually made with an excess of alcohol. The OH numbers are preferably at 30 to 200, particularly preferably at 80 to 180 mg KOH / g, the acid numbers are, for example, from 1 to 100, preferably from 10 to 50. The weight-average molar masses are, for example, 500 to 8000, preferably 1000 to 4000 g / mol.

Component B) can be composed of components b1) in different ways. to b5) are produced. The production can be gradual or preferably done in a one-pot process. Implementation of the reactants can be done at elevated temperature, e.g. B. at temperatures from 120 to 240 ° C until the desired degree of polycondensation is reached is.

As component b1), glycidyl esters of alpha, alpha Dialkyl-substituted aliphatic monocarboxylic acids are used. Such compounds are commercially available, e.g. B. glycidyl ester of alpha, alpha-dialkyl substituted aliphatic monocarboxylic acids with 9 to 11 carbon atoms, for example of neodecanoic acids, Commercial products Cardura E, such as Cardura-E10, from Shell.

Aliphatic and / or cycloaliphatic are used as component b2) Polycarboxylic acids or their anhydrides, especially dicarboxylic acids used. Examples of aliphatic dicarboxylic acids are Succinic acid, adipic acid, sebacic acid, dodecanedicarboxylic acid. Cycloaliphatic dicarboxylic acids are particularly preferred, for example 1,2-, 1,2- and 1,4-cyclohexanedicarboxylic acid and 1,2- Cyclohexanedicarboxylic anhydride.

2,2-Dialkylalkanediols, in particular those, are used as component b3) with more than 5 carbon atoms in the molecule. Are particularly preferred 2,2-dialkyl-alkanediols-1,3, in particular with more than 5 carbon atoms in the Molecule; Examples include 2-ethyl-2-butylpropanediol-1,3,2-ethyl- 2-hexylpropanediol-1,3, 2-ethyl-2-ethylhexylpropanediol-1,3, 2,2-di- tert-butyl-propanediol-1,3, 2,2-diethyl-propanediol-1,3. To be favoured 2-ethyl-2-hexylpropanediol-1,3 and 2,2-di-ethylpropanediol-1,3 used.  

As component b4), polyols with at least one secondary OH Group can be used in the molecule. These preferably contain at least two primary OH groups. Examples include glycerin, 1,2-butanetriol and 1,2,6-hexanetriol.

Hydroxycarboxylic acids are used as component b5). Especially Hydroxycarboxylic acids with a tertiary bond are preferred Carboxyl group used. Preferred examples of this are 2,2- Dialkyl-omega-hydroxyalkyl-carboxylic acids-1, the alkyl radicals for example have 1 to 6 carbon atoms. Specific examples are 2,2-dimethylolpropionic acid and 3-hydroxypivalic acid. Preferred examples of hydroxy-functional polyesters of the component B) can be prepared from 1,2-cyclohexanedicarboxylic anhydride and / or 1,4-cyclohexanedicarboxylic acid as component b2), 2-ethyl-2- 1,3-butylpropanediol as component b3), glycerol and / or hexanetriol 1,2,6 as component b4), and dimethylolpropionic acid as component b5). A particularly preferred polyester component B) is produced from 1,2-cyclohexanedicarboxylic acid anhydride as component b2), 2-ethyl-2- 1,3-butylpropanediol as component b3), glycerol as component b4), and dimethylolpropionic acid as component b5).

The hydroxy-functional siloxane used as component C) Polyesters are polycondensation products of components c1) to c5) and one or more alpha, omega-hydroxy, carboxy and / or epoxy-functional polysiloxanes (c6). Components c1) to c5) correspond to the qualitative composition of the Components b1) to b5). Examples of components c1) to c5) are thus the examples given above for b1) to b5). The Component c6) preferably corresponds to the general below Formula I:

wherein the radicals R 'may be the same or different and alkyl radicals  with 1 to 6 carbon atoms and in which the radicals R are the same or can be different and

mean, wherein Alk and Alk ′ alkylene groups with 1 to 6 There are carbon atoms and several contained in one molecule Alkylene groups can be the same or different, n = 8 to 40; m = 2 to 30; p = 1 to 20.

The OH numbers of component C) are preferably 30 to 200, particularly preferably at 80 to 180 mg KOH / g, the acid numbers z. B. at 1 to 100, preferably 10 to 50. The weight average molecular weights amount to z. B. 500 to 8000, preferably 1000 to 4000 g / mol.

The coating compositions according to the invention contain as component D) conventional crosslinking agents, for example aminoplast resins and / or blocked and / or non-blocked di- and Polyisocyanates. Preferably contain the invention Coating agents di- and / or polyisocyanates as crosslinkers. Conventional aminoplast resins can be used. examples for Aminoplast resins are alkylated condensates which are produced by the reaction of Aminotriazines and amidotriazines can be prepared with aldehydes. According to known technical processes, amino or amido groups load-bearing compounds such as melamine, benzoguanamine, dicyandiamide, Urea, N, N'-ethylene urea in the presence of alcohols, such as Methyl, ethyl, propyl, iso-butyl, n-butyl and hexyl alcohol with Aldehydes, especially formaldehyde, condensed. The reactivity such amine resins is determined by the degree of condensation that Ratio of the amine or amide component to the formaldehyde and by Type of etherification alcohol used. Preferably used Melamine resins etherified with n- or iso-butanol and their Degree of etherification is 1.0.

The aminoplast resins can also be present together with polyisocyanates. The proportion of aminoplast resins in the mixture is preferably below 50% by weight, based on the weight of component D).

As polyisocyanates mixed with the aminoplast resins, however preferably also be used alone as crosslinking component D) can, in particular, are aliphatic, cycloaliphatic and araliphatic suitable. Preferred diisocyanates are preferred Hexamethylene-1,6-diisocyanate, 3,5,5-trimethylhexamethylene-1,6- diisocyanate, isophorone diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, Bisisocyanatocyclohexylmethane, tetramethylxylylene diisocyanate (TMXDI)  used.

Also suitable as polyisocyanates are, for example, biuret Group-containing polyisocyanates, e.g. B. reaction products from 3 moles Hexamethylene diisocyanate with 1 mole of water with an NCO content of approx. 22 %, or polyisocyanates containing isocyanurate groups, the z. B. by Trimerization of 3 moles of hexamethylene diisocyanate can be produced with an NCO content of about 21.5% or containing urethane groups Polyisocyanates, which, for. B. Represent reaction products from 3 moles aliphatic or cycloaliphatic diisocyanates with 1 mole of triol, e.g. B. Trimethylolpropane. Preferably used aliphatic Diisocyanate is the isophorone diisocyanate.

The polyisocyanate crosslinking agents can be partial or, if longer, Time storable, d. H. one-component coating agent is desired, fully monofunctional with active hydrogen Connections are blocked. Choosing the under regression of the free Blocking agent which can be split off again thermally depends on the prevailing stoving conditions at the Hardening of the coating agent according to the invention. The are preferred Polyisocyanate crosslinker used uncapped.

The usual blocking agents for blocking purposes can be for example CH-acidic, NH- or OH-functional compounds are used, the crosslinking with under curing conditions enable hydroxy-functional binders. examples for Blocking agents that can be used are oximes and CH-acidic compounds such as Malon or acetoacetic ester. It can be convenient to do different things Capping agent to apply simultaneously what is inside of a polyisocyanate molecule or in a mixture.

The coating agents according to the invention can be used in addition to those already mentioned Solvents also contain customary auxiliaries, e.g. B .: Leveling agents, for example based on (meth) acrylic Homopolymers, silicone oils, plasticizers such as phosphoric acid, Phthalic or citric acid esters, matting agents such as pyrogenes Silicon oxide. Rheology influencers, such as microgels, NAD (= non-aqueous  dispersions), disubstituted ureas ("sagging control agents"), hydrogenated castor oil, catalysts, e.g. B. phosphoric acid, Phosphoric acid esters, dicarboxylic acid half esters, citric acid; organic Metal salts such as dibutyltin dilaurate, zinc naphthenate and also tertiary Compounds containing amino groups such as triethylamine.

The coating compositions according to the invention can be in aqueous and non- be formulated in aqueous form. To formulate watery Coating agents it is advisable to use components A), B) and C) which have an acid number range above about 30. These Components containing acid functions can then be partially or completely neutralized with amines and then diluted with Water can be transferred into the aqueous phase.

The coating compositions according to the invention are particularly suitable for Creation of a transparent top coat (clear coat) at Manufacture of oven drying multilayer coatings. The top layer can for example, applied by the wet-on-wet method, whereupon both layers are hardened together. The invention therefore relates to also the process for the production of multilayer coatings or the Use of the coating agents for their manufacture. The Solvent-containing coating compositions according to the invention can be used as transparent topcoats on layers of aqueous or solventborne basecoats e.g. B. for the production of curable Multi-layer coatings can be applied.

Pigmented coating agents can also be provided. This can be done using conventional organic and / or inorganic color pigments and / or fillers, such as titanium dioxide, micronized titanium dioxide, Iron oxide pigments, carbon black, silicon dioxide, barium stilfate, micronized Mica, talc, azo pigments, phthalocyanine pigments, quinacridone or Pyrrolopyrrole pigments are used.

The coating compositions according to the invention are produced by known processes,  such as B. spraying, dipping, rolling or knife application. Doing so on the one already provided with further layers of lacquer Substrate of the top coat applied. The invention Coating agents can also be made using supercritical Carbon dioxide can be applied as a solvent by spraying. Here the content of organic solvents can be greatly reduced. After an evaporation phase, the applied coating agent is preferred networked by heating. The stoving temperatures are preferred between 80 and 160 ° C, particularly preferably between 120 to 150 ° C. The Curing times are, for example, in the order of 20 to 40 Minutes. Crosslinking can also take place at lower temperatures be performed, e.g. B. at 20 to 80 ° C. The layer thickness of the baked film is approx. 15-50 µm. This creates a cross-linked, hard, glossy lacquer coating. A preferred one Embodiment is the application of the invention Coating agent as a clear coat on a basecoat. It can wet-on-wet, or the basecoat is applied beforehand Heating dried. There is a particularly good bond between the two Layers.

With coating compositions formulated according to the invention as clear lacquers for example basecoats are overcoated, the usual Topcoat pigments may contain, preferably contain the basecoats Effect pigments, such as B. Metallic pigments. As the binder base of the Basecoats are preferred polyester, polyurethane or acrylic resins used. These binders can optionally be crosslinked, e.g. B. melamine or isocyanate derivatives are crosslinked.

The coating compositions according to the invention are particularly suitable for Top coats or clear coats, which are preferred in the automotive sector, however, can also be used in other areas.

The use of the coating agent according to the invention in the Multi-layer painting is particularly suitable for automotive OEM painting suitable, but it can also be used for other purposes, such as e.g. B. in car refinishing, for household appliances or in Furniture industry.  

The coating compositions according to the invention are particularly suitable for Production of a transparent top layer of an oven drying Multilayer coating. They are particularly suitable for the Series painting of motor vehicle bodies and their parts.

Those produced using the coating compositions according to the invention Topcoat layers, e.g. B. Clear lacquer layers are characterized by a superior acid resistance, especially sulfuric acid resistance and excellent scratch resistance, which is a superior Exhibits durability. They are free of craters. Subsequent layers, as they e.g. B. be applied to touch-up paints, draw through good adhesion to those produced according to the invention Coating layers.

The following examples serve to illustrate the invention. All Parts refer to the weight.

Preparation of the (meth) acrylic copolymers (component A)) example 1

In a 2 liter three-necked flask equipped with a stirrer, Contact thermometer, ball cooler and dropping funnel, 308 g of an aromatic hydrocarbon with a Boiling range from 164 to 180 ° C and 22 g of n-butanol submitted and under Stirring and reflux cooling heated to 146 ° C.

Within 5 hours, a mixture of 14 g of acrylic acid, 220 g Styrene, 177 g ethylhexyl methacrylate, 128 g 2-hydroxyethyl methacrylate, 11 g of di-tert-butyl peroxide are metered in continuously. Then will the mixture was post-polymerized for 5 hours at 144 ° C., cooled to 80 ° C. and diluted with 97 g Solvesso 100 and 23 g n-butanol. The polymer Solution has a solids content of 55.4%, an acid number of 19.5 mg KOH / g, an OH number of 100 mg KOH / g, each based on the Resin solids and a viscosity of 1880 mPa · s / 25 ° C.

Example 2

In a 2 liter three-necked flask, which is equipped with a stirrer, Contact thermometer, ball cooler and dropping funnel, 200 g of an aromatic hydrocarbon with a Boiling range from 164 to 180 ° C and 120 g of butyl acetate and heated to 144 ° C. while stirring and reflux cooling.

A mixture of 25 g of 1,4-butanediol is monoacrylate, 164.8 g isobutyl acrylate, 195 g ethylhexyl methacrylate, 225.2 g of 2-hydroxypropyl methacrylate, 10 g of di-tert-butyl peroxide and 30 g tert-butyl peroctoate metered in continuously. Then the Batch polymerized at 144 ° C for 6 hours, cooled to 80 ° C and diluted with 30 g butyl acetate. The polymer solution has one Solids of 64.5%, an acid number of 3.5 mg KOH / g, an OH number of 160 mg KOH / g and a viscosity of 365 mPa · s / 25 ° C.

Production of the polyester (component B)) Example 3

In a 2 liter three-necked flask equipped with a thermometer and stirrer and capacitor are 300.0 g (1,200 mol) of CARDURA® E10 (commercial product = Versatic Acid Glycide Ester), 69.4 g (0.754 mol) glycerol, 98.3 g (0.614 mol) 2.2'- Ethyl butyl propanediol-1,3,412.4 g (2.678 mol), Hexahydrophthalic anhydride and 143.3 g (1.070 mol) Dimethylolpropionic acid submitted, melted and with stirring and Transfer of inert gas heated to 170 ° C. Then with one Heating rate from 20 ° C / h to 210 ° C. After reaching one Acid number of 72 mg KOH / g is cooled to 120 ° C and with xylene diluted a solid of 70%. The polyester has an acid number of 70.5 mg KOH / g and a viscosity of 1450 mPa · s / 25 ° C.

Example 4

In a 2 liter three-necked flask equipped with a thermometer and stirrer and capacitor are 300.0 g (1,200 mol) CARDURA® E10 (commercial product) 88.5 g (0.962 mol) glycerin, 125.3 g (0.783 mol) 2.2-  Ethylbutyl-propanediol-1,3,417.9 g (2.713 mol) Hexahydrophthalic anhydride and 95.6 g (0.713 mol) Dimethylolpropionic acid submitted, melted and with stirring and Transfer of inert gas heated to 170 ° C. Then with one Heating rate from 20 ° C / h to 210 ° C. After reaching one Acid number of 42 mg KOH / g is cooled to 120 ° C and with xylene diluted a solid of 70%. The polyester has an acid number of 40.5 mg KOH / g and a viscosity of 1660 mPas / 25 C.

Production of the siloxane polyester (component C)) Example 5

In a 2 liter three-necked flask equipped with a thermometer and stirrer and capacitor are 300.0 g (1,200 mol) of CARDURA® E10 (commercial product), 69.3 g (0.754 mol) glycerol, 98.2 g (0.614 mol) 2.2'- Ethylbutyl-propanediol-1,3,387.5 g (2.516 mol) Hexahydrophthalic anhydride, 100.2 g (0.107 mol) of Tegomer® H-Si 2111 (Commercial product) and 71.7 g (0.535 mol) Dimethylolpropionic acid submitted, melted and with stirring and Transfer of inert gas heated to 170 ° C. Then with one Heating rate from 20 ° C / h to 210 ° C. After reaching one Acid number of 21 mg KOH / g is cooled to 120 ° C and with xylene diluted a solid of 70%. The siloxane polyester has one Acid number of 20.0 mg KOH / g and a viscosity of 1400 mPa · s / 25 ° C. Tegomer H-Si 2111 = hydroxy-functional organopolysiloxane.

Example 6

In a 2 liter three-necked flask equipped with a thermometer and stirrer and capacitor are 300.0 g (1,200 mol) of CARDURA® E10 (commercial product), 79.7 g (0.866 mol) glycerin, 112.9 g (0.706 mol) 2,2′-Ethylbutyl-propanediol-1,3,359.1 g (2.332 mol) Hexahydrophthalic anhydride, 100.2 g (0.107 mol) of Tegomer® H-Si 2111 (Commercial product) and 71.7 g (0.535 mol) Dimethylolpropionic acid submitted, melted and with stirring and Transfer of inert gas heated to 170 ° C. Then with one Heating rate from 20 ° C / h to 210 ° C. After reaching one  Acid number of 21 mg KOH / g is cooled to 120 ° C and with xylene diluted a solid of 70%. The siloxane polyester has one Acid number of 20.5 mg KOH / g and a viscosity of 920 mPas / 25 C.

Example 7

In a 2 liter three-necked flask equipped with a thermometer and stirrer and capacitor are 320.0 g (1.280 mol) CARDURA® E10 (commercial product), 67.5 g (0.734 mol) glycerin, 88.1 g (0.550 mol) 2.2'- Ethylbutyl-propanediol-1,3,320.1 g (2.078 mol) Hexahydrophthalic anhydride, 150.3 g (0.127 mol) Tegomer® E-Si 2130 (Commercial product) and 71.7 g (0.535 mol) Dimethylolpropionic acid submitted, melted and with stirring and Transfer of inert gas heated to 170 ° C. Then with one Heating rate from 20 ° C / h to 210 ° C. After reaching one Acid number of 21 mg KOH / g is cooled to 120 ° C and with xylene diluted a solid of 70%. The siloxane polyester has one Acid number of 20.2 mg KOH / g and a viscosity of 1230 mPa · s / 25 ° C. Tegomer E-Si 2130 = glycidyl-functional organopolysiloxane.

Example 8

In a 2 liter three-necked flask equipped with a thermometer and stirrer and capacitor are 350.0 g (1,400 mol) of CARDURA E10 (commercial product) 110.0 g (0.821 mol) of 1,2-hexanetriol, 81.3 g (0.616 Mol) 2,2'-diethyl-propanediol-1,3,360.7 g (2.097 mol) 1,4-cyclohexanedicarboxylic acid, 82.9 g (0.081 mol) of Tegomer C-Si 2141 (Commercial product) and 71.7 g (0.535 mol) Dimethylolpropionic acid submitted, melted and with stirring and Transfer of inert gas heated to 170 ° C. Then with one Heating rate from 20 ° C / h to 210 ° C. After reaching one Acid number of 21 mg KOH / g is cooled to 120 ° C and with xylene diluted a solid of 70%. The siloxane polyester has one Acid number of 20.5 mg KOH / g and a viscosity of 2100 mPa · s / 25 ° C. Tegomer C-Si 2141 = carboxyl-functional organopolysiloxane.

Production of clear coats Example 9

356 parts of the (meth) acrylic copolymer solution from Example 2, 285 parts the polyester resin solution from Example 4 and 72 parts of the siloxane Polyester resin solution from Example 6 are mixed homogeneously and then under the running stirrer 22 parts of a mixture commercially available Light stabilizers (HALS and benzotriazole derivative in a ratio of 1: 1), 5 parts of a 1% xylene dibutyltin dulaurate solution and 260 Parts of a solvent mixture of ethoxypropylacetate, Butyl diglycol acetate and high-boiling aromatic hydrocarbons in a ratio of 10: 6: 40 added.

In 100 parts of this solution, 42 parts of an 82% solution are one customary aliphatic isocyanurate polyisocyanate in xylene Butyl acetate = 1: 1 stirred in homogeneously. This clear coat was like explained below for the production of a multi-layer coating used.

With the commercially available used in automotive OEM painting cathodic electrodeposition paint (KTL) (18 µm) and commercially available filler (35 µm) pre-coated body panels with commercially available water-borne metallic basecoat in one Dry film thickness of 15 µm painted and 6 min. at 80 ° C predried. Immediately afterwards was the one described above Clear coat in a dry film layer thickness of 35 µm by spray application applied wet-on-wet and after 5 min. Flash off at room temperature 30 min. Branded at 130 ° C (object temperature).

Example 10

The procedure is analogous to Example 9, with the difference that 360 Parts of the (meth) acrylic copolymer solution from Example 2, 216 parts of Polyester resin solution from Example 4, 144 parts of the siloxane Polyester resin solution from Example 6 and 253 parts of Solvent mixture were used.

Example 11

The procedure is analogous to Example 9, with the difference that 359 Parts of the (meth) acrylic copolymer solution from Example 2, 287 parts of Polyester resin solution from Example 3, 72 parts of the siloxane Polyester resin solution from Example 6 and 255 parts of Solvent mixture were used.

To test the clear coats for scratch resistance, the stroke-thrust Method used with the Erichsen-Peters block, type no. 265. The Dimensions are: 75 × 75 × 50 mm, footprint = 3750 mm². The weight is 2 kg. Under the sanding block is a 2.5 mm with Velcro thick wool felt, dimensions 30 × 50 mm, glued. Then 1 g becomes one water-soluble grinding paste evenly on the contact surface distributed. 10 double strokes are carried out in 9 s. The stroke thrust takes place parallel to the 75 mm edge of the block, the grinding path is 90 mm in one direction. Then rinse with cold water, dried and a gloss measurement carried out at an angle of 20. As a measure of the scratch resistance of a paint is the after Remaining residual gloss indicated in percent as a result of grinding stress.

Clearcoats according to the invention

Claims (13)

1. Coating agents based on hydroxy-functional (meth) acrylic copolymers, hydroxy-functional polyester resins, crosslinking agents, customary paint additives and solvents, characterized in that they contain binders based on:

• A) 20 to 60% by weight of one or more (meth) acrylic copolymers containing hydroxyl groups,
• B) 0 to 60 wt .-% of one or more hydroxyl-functional polyester, obtainable by reaction of
  • b1) 10 to 30 mol% of one or more glycidyl esters al pha, alpha-dialkyl-substituted aliphatic monocarboxylic acids,
  • b2) 30 to 50 mol% of one or more aliphatic and / or cycloaliphatic polycarboxylic acids with less than 16 carbon atoms or their anhydrides,
  • b3) 5 to 20 mol% of one or more 2,2-dialkylalkane diols,
  • b4) 5 to 20 mol% of one or more polyols with at least one secondary OH group in the molecule,
  • b5) 5 to 15 mol% of one or more hydroxycarboxylic acids with at least one hydroxyl group and at least one carboxyl group in the molecule,

the sum of the mol% b1) to b5) adding up to 100 mol%,

• C) 5 to 50 wt .-% of one or more hydroxyl-functional siloxane polyesters obtainable by reaction of
  • c1) 15 to 30 mol% of one or more glycidyl esters alpha, alpha-dialkyl-substituted aliphatic monocarboxylic acids,
  • c2) 35 to 50 mol% of one or more aliphatic and / or cycloaliphatic polycarboxylic acids with less than 16 carbon atoms or their anhydrides,
  • c3) 8 to 20 mol% of one or more 2,2-dialkylalkane diols,
  • c4) 10 to 20 mol% of one or more polyols with at least one secondary OH group in the molecule,
  • c5) 5 to 15 mol% of one or more hydroxycarboxylic acids with at least one hydroxyl group and at least one carboxyl group in the molecule,
  • c6) 1 to 5 mol% of one or more alpha, omega-hydroxy, carboxy and / or epoxy functional polysiloxanes, the hydroxyl, carboxy and / or epoxy groups being bonded directly to silicon via an alkylene group,

wherein the sum of the mol% c1) to c6) adds up to 100 mol%, and the sum of the weight% of components A) to C) adds up to 100% by weight, and

• D) one or more crosslinkers of the di- and / or polyisocyanate type, which can be blocked and / or aminoplast resin.

2. Coating agent according to claim 1, characterized in that as Polycarboxylic acid component b2) and / or c2) cycloaliphatic Carboxylic acids or their anhydrides are used. 3. Coating agent according to claim 1 or 2, characterized in that as 2,2-dialkyl alkanediols of component b3) and / or c3) 2,2- Dialkyl-alkanediols-1,3 with more than 5 carbon atoms in the molecule be used. 4. Coating agent according to one of the preceding claims, characterized in that polysiloxanes of the general formula are used as component c6): in which the radicals R 'can be identical or different and mean alkyl radicals having 1 to 6 carbon atoms and in which the radicals R can be identical or different and mean in which Alk and Alk ′ are alkylene groups having 1 to 6 carbon atoms and several alkylene groups contained in one molecule can be identical or different, n = 8 to 40; m = 2 to 30; p = 1 to 20. 5. Coating agent according to one of the preceding claims, characterized characterized in that a (meth) acrylic copolymer as component A) is used with an acid number of 1 to 50 mg KOH / g, one Hydroxyl number of 30-200 mg KOH / g, a weight average of Molar mass (Mw) from 2000 to 20,000 and a glass transition temperature from -20 ° C to + 80 ° C. 6. Coating agent according to one of the preceding claims, characterized characterized in that one or more polyesters as component B) are used, with an acid number of 1-100 mg KOH / g, one Hydroxyl number of 30-200 mg KOH / g and a weight average of  Molar mass (Mw) of 500-8000 g / mol. 7. coating agent according to one of claims 1 to 6, characterized characterized in that it is pigment-free or with transparent pigments is formulated as a clear coat. 8. Process for the production of multi-layer coatings by application a basecoat layer on a possibly already with a or a plurality of coating layers, and Paint over the resulting basecoat after drying or wet-on-wet with a top coat layer made of a transparent Coating agent according to one of claims 1 to 7. 9. Process for the production of multi-layer coatings by application a pigmented topcoat layer on a possibly already substrate provided with one or more coating layers, characterized in that the pigmented top coat layer a coating agent is created from one of claims 1 to 7. 10. The method according to claim 8 or 9, characterized in that it for the production of multi-layer coatings from Motor vehicle bodies or parts thereof is carried out. 11. Use of the coating agent according to one of claims 1 to 7 for Production of transparent cover layers of multilayer coatings, especially in the automotive sector.