Powder coating useful as a mat coating.

The present invention relates to powder coatings based on epoxy resins and a mixture of certain di-, tri- or tetrakis (ß-carboxyethyl) -cyclohexanones or -cyclopentanones and a carboxyl-terminated saturated polyester, tolyl biguanide or dicyandiamide as curing and matting agent, and also Use of such powder coatings for the production of matt coatings. GB Patent 1,033,697 discloses unsubstituted or alkyl-substituted tetrakis (β-carboxyethyl) cyclohexanones and cyclopentanones as curing agents for epoxy resins. The hardened resins are clear and have good mechanical properties.

To produce matt surfaces, matting agents are known to be added to the powder resins. Additives that are often used in solvent-based paints, such as silica, talc, mica, chalk or metal soaps, do not produce the desired matting effect in powder paints. Either the reduction in the degree of gloss is insufficient, or if the matting effect is achieved, a deterioration in the film properties of the coating, such as adhesion, flexibility, impact resistance or chemical resistance, has to be accepted. It is also known to use powder coatings which contain a specific curing agent for the production of coatings with a matt surface. For example, DE-OS 23 24 696 discloses using mono- or disalts of polycarboxylic acids with at least three carboxyl groups and cyclic amidines as such a curing agent. However, the preparation of these amidine salts is technically complex because it makes it difficult to control the reaction in such a way that only mono- or disalts are formed.

It has now been found that when using certain hardener mixtures based on di-, tri- or tetrakis (ß-carboxyethyl) cyclohexanones or pentanones or polyacetals containing carboxyl groups in epoxy resin powder coatings, a strong gloss reduction is achieved without significantly impairing the other coating properties. The present invention relates to a powder coating<ul id="ul0001" list-style="none"><li>(a) an epoxy resin,</li><li>(b) at least one polycarboxylic acid of the formula I or II<chemistry id="chem0001" num="0001"><img file="EP0366608A2_D0001.tif" /></chemistry></li><li>wherein R¹, R², R³ and R⁴ each independently represent a hydrogen atom, C₁-C₄-alkyl or the radical -CH₂-CH₂-COOH, R⁵ and R⁶ each independently represent a hydrogen atom, C₁-C₄-alkyl, the radical -CH₂- CH₂-COOH or together represent an unsubstituted or alkyl-substituted methylene or polymethylene group with 1 to 7 C atoms, at least two of the substituents R¹ to R⁶ representing the radical -CH₂-CH₂-COOH, the substituents R are each independently a hydrogen atom or<chemistry id="chem0002" num="0002"><img file="EP0366608A2_D0002.tif" /></chemistry> stand, the ratio of the carboxyl groups contained in the 2-carboxyl-cyclohexanecarbonyl radical to the RO groups being 0.5 to 1.0, m being a number from 2 to 5, n being a value from zero to 10 and X being a direct one Bond, an aliphatic or cycloaliphatic radical, and</li><li>(c) a carboxyl-terminated saturated polyester, tolyl biguanide or dicyandiamide.</li></ul>

The usual epoxy resins suitable for powder coatings can be used as component (a). Such compounds are described for example in DE-OS 28 38 841. The content of this published specification is therefore part of the present invention.

The resins used preferably have an epoxy content of 0.5 to 12 equivalents per kg. The preferred epoxy resins are solid at room temperature and, if necessary, can be pre-extended by reaction with, for example, a dihydric phenol.

Epoxy resins are preferred which contain on average more than one epoxy group in the molecule and are polyglycidyl derivatives of aromatics or heteroaromatics, in particular of aromatics.

Particularly preferred resins are optionally advanced polyglycidyl ethers of 2,2-bis (4'-hydroxyphenyl) propane (bisphenol A), 2,2-bis (3 ', 5'-dibromo-4'-hydroxyphenyl) propane ( Tetrabromobisphenol A), of bis (4-hydroxyphenyl) methane (bisphenol F) and of novolaks, polyglycidyl derivatives of 4,4'-diaminodiphenylmethane, of 4,4'-diaminodiphenylsulfone and of 2,4,6-trihydroxy-1, 3,5-triazine (cyanuric acid), such as triglycidyl isocyanurate.

The polycarboxylic acids of formula I are known compounds. For example, cycloaliphatic polycarboxylic acids of the formula I are described in the aforementioned GB patent 1,033,697. Aliphatic polycarboxylic acids of formula I are known for example from DE-OS 26 09 659.

In the formula I, R¹ to R⁴ are preferably the carboxylethyl radical and R⁵ and R⁶ are preferably together an unsubstituted or alkyl-substituted polymethylene group having 2 to 7 C atoms, in particular an unsubstituted polymethylene group having 2 to 4 C atoms. Suitable compounds of the formula I are, for example, 2,2,6,6-tetra- (β-carboxylethyl) cyclopentanone, 2,2,6,6-tetra- (β-carboxylethyl) cyclohexanone, 2,2,4,4 -Tetra- (ß-carboxylethyl) -pentanone- (3) and 1,1,3,3-tetra- (ß-carboxylethyl) -acetone.

The compounds of formula II have not yet been described in the literature and can be prepared by using compounds of formula III<chemistry id="chem0003" num="0003"><img file="EP0366608A2_D0003.tif" /></chemistry> wherein X, m and n have the same meaning as in formula II, with hexahydrophthalic anhydride to give a compound of formula II. In general, hexahydrophthalic acid is used in such amounts that at least half of all HO groups in the compounds of the formula III are converted into 2-carboxylcyclohexane carbonyl groups. At least 60% of all hydroxyl groups, in particular at least 70% of all hydroxyl groups, in the compounds of the formula III are preferably converted into 2-carboxylcyclohexane carbonyl groups.

The compounds of the formula II, which were developed specifically for the production of the powder coating materials according to the invention, thus likewise represent an object of the invention.

In formula II, X preferably denotes a direct bond or an aliphatic or cycloaliphatic radical containing up to 20 carbon atoms. In particular, X denotes a direct bond or an aliphatic radical with up to 12 carbon atoms. Furthermore, m is preferably the number 2 or 3 and n is preferably zero or a number from 0.1 to 3.

Compounds of the formula III, in which n represents the number 1 or a number greater than 1, are known and can be prepared in a known manner by the process disclosed, for example, in US Pat. No. 4,374,953, by using a polyol of the formula IV<chemistry id="chem0004" num="0004"><img file="EP0366608A2_D0004.tif" /></chemistry> wherein m has the same meaning as in formula II or III, polycondensed with an aliphatic or cycloaliphatic dialdehyde or an aliphatic or cycloaliphatic diketone to form a hydroxyl-containing polycycloacetal or polycycloketal of the formula III.

Suitable polyols of the formula IV are, for example, the aforementioned polyols of the formula III, in which n is zero. Dialdehydes or diketones suitable for the process are, for example, glyoxal, glutaraldehyde, succinaldehyde and 1,4-cyclohexanedione.

The polycondensation of the polyol of the formula IV with the dialdehyde or diketone to the hydroxyl-containing polycycloacetal of the formula III is preferably carried out in an inert organic solvent, such as toluene, with an acid catalyst, such as in the presence of H₃PO₂, and with the simultaneous removal of water from the Reaction mixture.

In the curable mixtures according to the invention, compounds of the formula II which are preferably used are those which have a softening temperature of 60 to 180 ° C., preferably between 80 to 140 ° C.

Saturated polyesters suitable as component (c) with terminal carboxyl groups preferably have on average more than two carboxyl groups per molecule, an acid number from 15 to 100 and an average molecular weight from 500 to 10,000. The polyesters used are preferably solid at room temperature and have a glass transition temperature of 40 to 80 ° C.

Such polyesters are described, for example, in US Pat. No. 3,397,254 and in DE Offenlegungsschrift 21 63 962. They can be obtained, for example, by reacting polyesters with terminal hydroxyl groups with tricarboxylic anhydrides or tetracarboxylic dianhydrides. The polyesters with terminal hydroxyl groups in turn are reaction products of polyols with dicarboxylic acids or acid anhydrides and advantageously have an average degree of polymerization of at least 3, generally from 3 to 25, preferably from 5 to 12. Suitable polyols are, for example, ethylene glycol, glycerol, 1,4- Butanediol, neopentanediol and cyclohexanediol.

Suitable dicarboxylic acids are, for example, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid or sebacic acid.

Suitable tricarboxylic acid anhydrides are, for example, anhydrides of aliphatic tricarboxylic acids, such as tricarballylic acid (1,2,3-propane tricarboxylic acid), of aromatic tricarboxylic acids, such as trimellitic acid (benzene-1,2,4-tricarboxylic acid) and hemimellitic acid (benzene-1,2,3-tricarboxylic acid) ), or of cycloaliphatic tricarboxylic acids, such as 6-methylcyclohex-4-ene-1,2,3-tricarboxylic acid. Suitable tetracarboxylic dianhydrides are, for example, pyromellitic dianhydride or benzophenone3,3 ', 4,4'-tetracarboxylic dianhydride.

Tolyl biguanide and dicyandiamide, which can also be used as component (c) in the powder coating according to the invention, are known and commercially available.

When using a carboxyl-terminated saturated polyester as component (c), this is expediently used together with a polycarboxylic acid of the formula I or II with respect to the epoxy resin (a) in approximately stoichiometric amounts, that is to say the ratio of the sum of the carboxyl equivalents per epoxide equivalent is 0 , 5 to 1.5, preferably from 0.7 to 1.3 and in particular from 0.8 to 1.2. The ratio of a polycarboxylic acid of the formula I or II to the carboxyl-terminated saturated polyester in the powder coating according to the invention can be from 1:10 to 10: 1. The polycarboxylic acid of the formula I or II and the carboxyl-terminated saturated polyester are preferably present in the powder coating according to the invention in a ratio of 1: 5 to 5: 1, in particular 1: 3 to 3: 1. If tolyl biguanide or dicyandiamide is used as component (c), the proportion of a polycarboxylic acid of the formula I or II in the powder coating according to the invention is generally only 10 to 90 equivalent%, preferably 20 to 80 equivalent%, in particular 40 to 60 equivalent %, the stoichiometric amount required for the complete curing of the epoxy resin. The proportion of dicyandiamide or tolylbiguanide required for complete curing of the epoxy resin can then be calculated, since the person skilled in the field of epoxy resin formulations knows the amount of dicyandiamide or tolylbiguanide required for curing an epoxy resin. Generally, the amount of these curing agents is in the range of 5 to 30 parts by weight per 100 parts by weight of the epoxy resin. If necessary, hardening accelerators can also be added to the powder coatings according to the invention. In addition to tert. Amines, Mannich bases and quaternary ammonium bases are suitable for N-heterocyclic compounds, such as pyrazoles, imidazoles, pyrroles, pyridines, pyrazines, indoles and piperidines. Heterocycles with at least one tertiary nitrogen atom in the ring, such as N-substituted pyrroles, for example N-methylpyrrole, N-substituted pyridines, for example, are preferred N-methyl-, N-ethyl- and N-benzylpyridines, N-substituted pyrazines, for example N, N′-dimethyl- and N, N′-diethylpyrazines, N-substituted indoles, for example N-methyl- and N-ethylindoles, N-substituted piperidines, for example N-methyl-, N-ethyl- and N-isopropylpiperidines and, preferably imidazoles, such as imidazole, N-substituted imidazoles, for example 1-methylimidazole and 1- (2 ′, 4′-diamino-s-triazin-6′-ylethyl) -2-methylimidazole (6- [2- (2-methyl-1H-imidazol-1-yl) ethyl] -1,3,3-triazine-2,4-diamine), C-substituted imidazoles, such as 2-methylimidazole, 2-ethylimidazole, 2-n-propylimidazole, 4-methylimidazole, 2-methyl-4-phenylimidazole, 2 -Phenylimidazole, 2-ethyl-4-methylimidazole and benzimidazole.

Particularly preferred accelerators are N, N-dimethyl-1,3-propanediamine, 2,4,6-tris (dimethylaminomethyl) phenol, N, N, N ′, N′-tetramethylethylenediamine, triethylamine, benzyldimethylamine, 2-methylimidazole and 2- Ethyl 4-methylimidazole.

If desired, other additives customary in the coating industry, such as, for example, light stabilizers, dyes and in particular degassing agents, leveling agents and / or pigments, such as preferably TiO 2, can be added to the powder coatings.

Leveling agents are, for example, polyvinyl acetals, such as polyvinyl butyral (Movital® B 30 H from HOECHST), polyethylene glycol, polyvinyl pyrrolidone, glycerin, acrylic copolymers, such as Modaflow® or Acrylron® MFP from MONSANTO or PROTEX.

Benzoin is preferably used as the degassing agent.

The new powder coatings can be produced by simply mixing the components, for example in a ball mill. Another possibility of production consists in melting the components together, preferably in a spraying machine, such as, for example, in a Buss co-kneader, and then comminuting the cooled mass. The mixtures preferably have a particle size in the range from 0.015 to 500 μm, and in particular from 10-75 μm.

Matt coatings are obtained by curing the powder coating materials of the invention. The powder coating is applied to the object to be coated and heated to at least 120 ° C., preferably 150 to 250 ° C., in order to cure the resin.

The invention also relates to the use of the powder coating according to the invention for the production of matt coatings on surfaces, in particular of metals, such as aluminum or steel.

To produce the powder coatings according to the invention according to the following examples, some constituents are synthesized or formulated as follows:

2,2,5,5-tetra (β-carboxyethyl) cyclopentanone

633 g of acrylonitrile are added dropwise at 20 ° C. to 250 g of cyclopentanone and 38 g of 40% aqueous KOH in 920 ml of tert-butyl alcohol with stirring. A precipitate forms during the dropping, and at the end of the addition there is a thick paste which is stirred for another hour and then filtered. The filter residue is washed with 400 ml of ice water. 725 g of 2,2,5,5-tetra- (β-cyanoethyl) cyclopentanone with a melting point of 157-159 ° C. are obtained.<tables id="tabl0001" num="0001"><table frame="all"><tgroup cols="4" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="39.37mm" /><colspec colnum="2" colname="col2" colwidth="39.37mm" /><colspec colnum="3" colname="col3" colwidth="39.37mm" /><colspec colnum="4" colname="col4" colwidth="39.37mm" /><thead valign="top"><row><entry namest="col1" nameend="col4" align="left">Elemental analysis for C₁₇H₂₀N₄O:</entry></row></thead><tbody valign="top"><row><entry namest="col1" nameend="col1" align="left">Calculated:</entry><entry namest="col2" nameend="col2" align="left">C = 68.90%</entry><entry namest="col3" nameend="col3" align="left">H = 6.80%</entry><entry namest="col4" nameend="col4" align="left">N = 18.90%</entry></row><row rowsep="1"><entry namest="col1" nameend="col1" align="left">Found:</entry><entry namest="col2" nameend="col2" align="left">C = 68.83%</entry><entry namest="col3" nameend="col3" align="left">H = 6.94%</entry><entry namest="col4" nameend="col4" align="left">N = 18.00%.</entry></row></tbody></tgroup></table></tables>

466 g of the nitrile obtained above are heated with 442 g of KOH at 95 ° C. for 6 hours and then with 786 g of conc. Hydrochloric acid (37%) brought to pH 1 at room temperature, a precipitate forming. The precipitate is filtered off and washed with 400 ml of ice water. 464 g of 2,2,5,5-tetra- (β-carboxyethyl) cyclopentanone with a melting point of 152-155 ° C. are obtained.<tables id="tabl0002" num="0002"><table frame="all"><tgroup cols="3" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="52.50mm" /><colspec colnum="2" colname="col2" colwidth="52.50mm" /><colspec colnum="3" colname="col3" colwidth="52.50mm" /><thead valign="top"><row><entry namest="col1" nameend="col3" align="left">Elemental analysis for C₁₇H₂₄O₉:</entry></row></thead><tbody valign="top"><row><entry namest="col1" nameend="col1" align="left">Calculated:</entry><entry namest="col2" nameend="col2" align="left">C = 54.83%</entry><entry namest="col3" nameend="col3" align="left">H = 6.50%</entry></row><row rowsep="1"><entry namest="col1" nameend="col1" align="left">Found:</entry><entry namest="col2" nameend="col2" align="left">C = 55.53%</entry><entry namest="col3" nameend="col3" align="left">H = 6.65%</entry></row></tbody></tgroup></table></tables>

Content of COOH groups, calculated: 10.74 equivalents / kg, found: 10.78 equivalents / kg.

2,2,4,4-tetra (β-carboxyethyl) pentanone

Using the procedure described for the preparation of 2,2,5,5-tetra (β-carboxyethyl) cyclopentanone and using pentanone- (3) instead of cyclopentanone, 2,2,4,4-tetra- (ß-carboxyethyl) pentanone with a melting point of 176-178 ° C. <tables id="tabl0003" num="0003"><table frame="all"><tgroup cols="3" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="52.50mm" /><colspec colnum="2" colname="col2" colwidth="52.50mm" /><colspec colnum="3" colname="col3" colwidth="52.50mm" /><thead valign="top"><row><entry namest="col1" nameend="col3" align="left">Elemental analysis for C₁₇H₂₆O₉:</entry></row></thead><tbody valign="top"><row><entry namest="col1" nameend="col1" align="left">Calculated:</entry><entry namest="col2" nameend="col2" align="left">C = 54.49</entry><entry namest="col3" nameend="col3" align="left">H = 6.94</entry></row><row rowsep="1"><entry namest="col1" nameend="col1" align="left">Found:</entry><entry namest="col2" nameend="col2" align="left">C = 54.22</entry><entry namest="col3" nameend="col3" align="left">H = 7.02</entry></row></tbody></tgroup></table></tables>

Content of COOH groups, calculated: 10.68 equivalents / kg found: 10.54 equivalents / kg.

2,2,6,6-tetra (β-carboxyethyl) cyclohexanone

Using the procedure described in the preparation of 2,2,5,5-tetra (β-carboxyethyl) cyclopentanone and using cyclohexanone instead of cyclopentanone, 2,2,6,6-tetra- (β-carboxyethyl) is obtained ) -cyclohexanone with a melting point of 174-176 ° C. <tables id="tabl0004" num="0004"><table frame="all"><tgroup cols="3" colsep="1" rowsep="0"><colspec colnum="1" colname="col1" colwidth="52.50mm" /><colspec colnum="2" colname="col2" colwidth="52.50mm" /><colspec colnum="3" colname="col3" colwidth="52.50mm" /><thead valign="top"><row><entry namest="col1" nameend="col3" align="left">Elemental analysis for C₁₈H₂₆O₉:</entry></row></thead><tbody valign="top"><row><entry namest="col1" nameend="col1" align="left">Calculated:</entry><entry namest="col2" nameend="col2" align="left">C = 55.95%</entry><entry namest="col3" nameend="col3" align="left">H = 6.78%</entry></row><row rowsep="1"><entry namest="col1" nameend="col1" align="left">Found:</entry><entry namest="col2" nameend="col2" align="left">C = 55.59%</entry><entry namest="col3" nameend="col3" align="left">H = 6.75%</entry></row></tbody></tgroup></table></tables>

COOH content, calculated: 10.35 equivalents / kg, found: 10.44 equivalents / kg.

Polyacetal I containing carboxyl groups

<ul id="ul0002" list-style="none"><li>a) 551 g of 2,2,6,6-tetramethylolcyclohexanol-1 and 1.9 g of hypophosphorous acid are suspended at 100 ° C. in 2000 ml of toluene. 455 ml of a 50% aqueous glutardialdehyde solution are added dropwise over the course of 50 minutes. By lowering the pressure to about 0.15 bar, distillation of water is started via a water separator. After the water separation has ended, the reaction mixture is heated under reflux at 1.0 bar for a further 2 hours. The reaction mixture is cooled to 30 ° C., the toluene phase is decanted, the product formed is dissolved in 350 ml of methanol, the methanol is distilled off on a rotary evaporator and the residue is dried at 120 ° C. and 0.02 bar. Yield: 640 g (93% of theory with n = 5.7) Softening point: 147 ° C<o ostyle="single">M</o>_n (Gel permeation chromatography in THF): 1839, <o ostyle="single">M</o>_w/<o ostyle="single">M</o>_n = 3.65 hydroxyl content: 5.47 Aeq./kg.</li><li>b) 50 g of the hydroxyl-containing polyacetal prepared under a) are suspended at 107 ° C. in 120 ml of methyl isobutylacetone. 34 g of hexahydrophthalic anhydride are added over the course of 2 hours. The reaction mixture is heated for a further 3 hours. The solvent is distilled on a rotary evaporator and dried at 90 ° C and 0.02 bar. Yield: 75 g (90% of theory) Softening point: 125 ° C<o ostyle="single">M</o>_n (Gel permeation chromatography in THF): 1636, <o ostyle="single">M</o>_w/<o ostyle="single">M</o>_n = 3.44 carboxyl content: 2.86 Aeq./kg.</li></ul>

Hardening accelerator A

Mixture of 87.5 parts of a carboxyl-terminated, saturated, solid polyester resin and 12.5 parts of tetradecyltrimethylammonium bromide.

Example 1:

A mixture of the following components is homogenized in an extruder (co-kneader from Buss, Pratteln, CH) at a temperature of 80 ° C: 817.6 g of a bisphenol A diglycidyl ether with a softening point (according to DIN 51 920) of 86 ° C. and an epoxy content of 1.3 equivalents / kg, 5.0 g Acrylron® MFP (butylated polyacrylate from Protex) as a leveling agent, 82.3 g Crylcoat® 314 (carboxyl-terminated saturated polyester with an acid number of 73 equivalents KOH / g and a glass transition temperature (T._G) of 60 ° C (DSC) from UCB, Belgium), 95.1 g of 2,2,5,5-tetra- (β-carboxyethyl) cyclopentanone, 2.0 g benzoin, 500.0 g TiO₂ and 20.0 g hardening accelerator A.

The extrudate is ground to a particle size of approximately 40 μm using known standard methods and electrostatically sprayed onto an aluminum sheet. After baking for 30 minutes at 200 ° C, a paint film is created with the following properties: Film thickness (µm) = 61 Erichsen deep drawing test according to DIN 53 156 (mm) = 9.3 Impact deformation, on the back *⁾ (cmkg) = 80 Gloss (∢ 60 °) (%) = 0 Yellow value according to DIN 6167 = 2.8 Course at 200 ° C **⁾ = good / very good.

*⁾ A stamp with a known weight is dropped on the coated aluminum sheet from behind from a certain height. The value obtained, height (cm) times weight (kg), shows the greatest impact at which the coating remains undamaged.)

(**) Test method in which the course of the coating is visually determined as moderate) good or very good.)

Example 2:

In exactly the same way as in Example 1, a paint powder is produced by mixing the following components: 762.5 g of the bisphenol A diglycidyl ether according to Example 1, 5.0 g Acrylron® MFP 153.5 g Crylcoat® 314 79.0 g of 2,2,5,5-tetra- (β-carboxyethyl) cyclopentanone, 2.0 g benzoin, 500.0 g TiO₂ and 20.0 g hardening accelerator A.

After baking for 30 minutes at 200 ° C, the film has the following properties: Film thickness (µm) = 54 Erichsen deep drawing test (mm) = 8.8 Rear impact test (cmkg) = 80 gloss (∢ 60 °) (%) = 4 Yellowness index (DIN 6167) = 3.1 Course at 250 ° C = very good.

Example 3:

In exactly the same way as in Example 1, a paint powder is produced by mixing the following components: 931.0 g of the bisphenol A diglycidyl ether according to Example 1, 5.0 g Acrylron® MFP 30.1 g of 2,2,5,5-tetra- (β-carboxyethyl) cyclopentanone, 37.7 g of tolyl biguanide, 2.0 g of benzoin and 500.0 g TiO₂.

After baking for 30 minutes at 200 ° C, the paint film has the following properties: Film thickness (µm) = 56 Erichsen deep drawing test (mm) = 9.5 Impact test on the back (cm · kg) = 160 Gloss (∢ 60 °) (%) = 4 Yellowness index (DIN 6167) - 3.5 Course at 200 ° C = good / moderate.

Example 4:

In exactly the same way as in Example 1, a paint powder is produced by mixing the following components: 876.0 g of the bisphenol A diglycidyl ether according to Example 1, 5.0 g Acrylron® MFP 92.0 g of polyacetal I containing carboxyl groups, 32.0 g of tolyl biguanide, 2.0 g of benzoin and 500.0 g TiO₂.

After baking for 30 minutes at 200 ° C, the paint film has the following properties: Film thickness (µm) = 66 Erichsen deep drawing test (mm) = 10 Impact test on the back (cm · kg) = 40 Gloss (∢ 60 °) (%) = 15 Yellowness index (DIN 6167) = 6.7 Course at 200 ° C = very good.

Example 5:

In the same way as in Example 1, a paint powder is produced by mixing the following substances: 730.0 g bisphenol A diglycidyl ether according to Example 1, 5.0 g Acrylron® MFP 27.0 g of tolyl biguanide, 23.0 g of 2,2,4,4-tetra- (β-carboxylethyl) pentanone- (3), 2.0 g of benzoin and 390.0 g TiO₂.

After baking for 30 minutes at 200 ° C, the paint film has the following properties: Film thickness (µm) = 54 Erichsen deep drawing test (mm) = 9.3 Impact test on the back (cm · kg) = 160 Gloss (∢ 60 °) (%) = 28 Yellowness index (DIN 6167) = 4.2 Course at 200 ° C = good / moderate.