Yellow methine dyes and their use for dyeing plastics

Abstract

The present invention relates to substituted 4-amino-6-methylbenzaldehyde derivatives of the formula (I), wherein R1 and R2 are the same or different and each represent optionally substituted alkyl, and R3 to R7 are the same or different and each represent hydrogen, halogen, cyano, optionally substituted alkyl or optionally substituted alkoxy, as novel yellow methine dyes. The invention also relates to a method for producing them and to their use for dyeing plastics.

Description

[0001] Thermostable methine dyes

[0002] The present invention relates to substituted 4-amino-6-methylbenzaldehyde derivatives of

[0003] Formula (I) wherein

[0004] R 1 and R 2 are the same or different and each represents optionally substituted alkyl, and R 3 to R 7 are identical or different and each represents hydrogen, halogen, cyano, optionally substituted alkyl or optionally substituted alkoxy, as novel yellow methine dyes, processes for their preparation and their use for dyeing plastics.

[0005] Although there are already a variety of yellow dyes on the market for coloring plastics, there is still a need for new dyes with improved properties. In particular, there is still a need to improve existing dyes with regard to the two properties of color strength and thermal stability. This is especially true for the application of dyes for the mass coloration of polyamide.

[0006] Bulk dyeing of synthetic polyamides places greater demands on the colorants used than bulk dyeing of other plastics. The melting points of synthetic polyamides are significantly higher, and the chemical reactivity of the molten polyamides, especially polyamide 6.6, is also significantly greater, so the heat stability of the colorants used must be exceptionally good. Few colorants meet these stringent requirements, especially when high lightfastness is also required.

[0007] EP-A 0225553 describes azo lakes that can be used to color polyamide in yellow shades. The use of Pigment Yellow 192 is also known. EP-A 0074515 discloses nickel azobarbituric acid complexes, which can also be used to produce yellow colorations of polyamide. Although these known pigments possess good thermal stability, they cannot be used to achieve transparent colorations of plastics. Furthermore, pigments can impair the mechanical properties of the polymers.

[0008] It is also known from the prior art to use solvent dyes to color plastics in transparent yellow shades. These dyes generally do not adversely affect the mechanical properties of the polymers.

[0009] A well-known soluble yellow dye is Solvent Yellow 93 (Cl 48160; CAS No. 4702-90-3)), both from the class of methine dyes, but with two 3H-pyrazol-3-one groups in the molecule.

[0010] P.-M. Chun et al., Styryl Dyes for Synthetic Polymer Fibers, J. appl. Chem. Biotechnol. 1978,28, 463-468 describe the reaction of numerous 4-(N-methyl-N-ß-cyanoethyl)aminobenzaldehydes and 4-(N-ethyl-N-ß-benzyloxyethyl)amino-2-methylbenzaldehydes with reactive methylene components, achieving optimal coloration and color fastness when using malononitrile, ethyl cyanoacetate and 2-cyanomethylbenzimidazole.

[0011] A. Thomas et al, Chemistry of Bis-2'-cyanoethyl Derivatives of Some Aromatic Primary Amines, Part I., Journal Indian Chem. Soc., Vol. 41, No. 1, 1964, describe the preparation and properties of bis-2'-cyanoethyl derivatives of primary amines.

[0012] JP S61 270747 A describes photopolymerizable compositions with high sensitivity to laser beams and uses 1-cyano-2-(P-dialkylaminophenyl)ethylene derivatives and 1-cyano-4-(P-dialkylaminophenyl)-l,3-butadiene derivatives as photoinitiator or as photoinitiator system.

[0013] However, the properties of these state-of-the-art colorants are not sufficient to meet current technical requirements and still need to be improved, particularly with regard to their fastness properties, such as light and heat resistance. In particular, colorants that absorb in the short-wavelength spectral range (absorption maximum approximately 380 to 420 nm) are lacking.

[0014] Surprisingly, it was found that by reacting substituted 4-amino-6-methylbenzaldehydes of the formula (II) wherein

[0015] R 1 and R 2are the same or different and each represents optionally substituted alkyl, and phenylacetonitrile derivatives of the formula (III)

[0016] R 3 to R 7 are identical or different and each represents hydrogen, halogen, cyano, optionally substituted alkyl or optionally substituted alkoxy, substituted 4-amino-6-methylbenzaldehyde derivatives for use as heat- or thermostable methine dyes which are suitable for use in polymers or plastics.

[0017] The present invention relates to substituted 4-amino-6-methylbenzaldehyde derivatives or dyes of the formula (I) wherein

[0018] R 1 and R 2 are the same or different and each represents optionally substituted alkyl, and

[0019] R 3 to R 7are identical or different and each represents hydrogen, halogen, cyano, optionally substituted alkyl or optionally substituted alkoxy. However, the invention also relates to the use of the substituted 4-amino-6-methylbenzaldehydes of the formula (II) wherein

[0020] R 1 and R 2 have the general and preferred meanings given for formula (I), and phenylacetonitrile derivatives of formula (III) where R 3 , R 4 , R 5 , R 6 and R 7which have the general and preferred meanings given for formula (I), as thermostable dyes in plastics or polymers, with the proviso that “thermostable” means a heat stability of > 385 °C to be determined on the respective plastic granulate according to DIN EN 12877-2 Method A (“Determination of the resistance of the colour to heat during the processing of colourants in plastics”).

[0021] The present invention further relates to the use of the substituted 4-amino-6-methylbenzaldehyde derivatives of the formula (I) according to the invention as thermostable dyes in plastics or polymers, preferably for the mass coloration of plastics. The substituted 4-amino-6-methylbenzaldehyde derivatives of the formula (I) to be used according to the invention can be used individually or in any desired mixture with one another.

[0022] For the sake of clarity, it should be noted that the scope of the present invention encompasses all definitions and parameters listed, either general or in preferred ranges, in any combination. This particularly applies to the quantities and parameters to be used for the individual components in the processes and uses claimed within the scope of this application. The standards cited within the scope of this application refer to the version applicable on the filing date of this invention. The terms "thermostable" and "heat-stable" are synonymous within the scope of this invention.

[0023] Alkyl in the meaning of R 1 to R 7 represents a straight-chain or branched saturated hydrocarbon radical which may be mono- or polysubstituted by identical or different substituents. The alkyl radicals mentioned preferably contain 1 to 6 carbon atoms, particularly preferably 1 to 4 carbon atoms.

[0024] The alkyl radicals mentioned are in particular methyl, ethyl, n-propyl, iso-propyl, n-butyl, sec-butyl, iso-butyl and tert-butyl, each of which may be mono- or polysubstituted by identical or different substituents.

[0025] Alkoxy in the meaning of R 3 to R 7 represents an alkyl radical linked to the remaining moiety via an oxygen atom, where alkyl represents a straight-chain or branched saturated hydrocarbon radical which may be mono- or polysubstituted by identical or different substituents. The alkoxy radicals mentioned preferably contain 1 to 6 carbon atoms, particularly preferably 1 to 4 carbon atoms.

[0026] The alkoxy radicals mentioned are in particular methoxy, ethoxy, n-propoxy, iso-propoxy, n-butoxy, sec-butoxy, iso-butoxy and tert-butoxy, each of which may be mono- or polysubstituted by identical or different substituents.

[0027] The alkyl radicals mentioned in the meaning of R 1 to R 7 are unsubstituted or mono- or polysubstituted by identical or different substituents. Possible substituents for the above-mentioned alkyl radicals include, for example, halogen atoms, in particular fluorine and / or chlorine atoms and / or aryloxy radicals.

[0028] Aryloxy radicals are aromatic hydrocarbon radicals having 6 to 10 carbon atoms which are unsubstituted or mono- or polysubstituted by identical or different substituents and whose aryl moiety is bonded to the remaining moiety via an oxygen atom. Aryloxy radicals are, in particular, phenoxy or naphthoxy radicals. Suitable substituents for the aryloxy radicals mentioned are halogen atoms, preferably fluorine or chlorine; alkyl, preferably C1-C8-alkyl, in particular n-propyl, isopropyl, butyl, isobutyl, tert-butyl, isooctyl, isononyl, or lauryl; alkoxy, preferably C1-C4-alkoxy, in particular methoxy and ethoxy; furthermore, cycloalkyl, preferably C5-C7-cycloalkyl, in particular cyclopentyl and cyclohexyl; and aryl, preferably phenyl.

[0029] Halogen in the meaning of R 3 to R 6represents in particular fluorine and chlorine. Preferred substituted 4-amino-6-methylbenzaldehyde derivatives of the formula (I) and their use as thermostable dyes are those in which R 1 and R 2 independently of one another represent unsubstituted C1-C4-alkyl or represent C1-C4-alkyl which is substituted by a phenoxy or naphthoxy radical which is optionally mono- or disubstituted by identical or different substituents, and R 3 to R 7 independently of one another represent hydrogen, halogen, cyano, unsubstituted C1-C4-alkyl or C1-C4-alkyl which is mono- to tri-substituted by identical or different halogen, unsubstituted C1-C4-alkoxy or C1-C4-alkoxy which is mono- to tri-substituted by identical or different halogen. Particular preference is given to substituted 4-amino-6-methylbenzaldehyde derivatives of the formula (I) and their use as thermostable dyes, wherein R 1represents unsubstituted C1-C4 alkyl, R 2 represents unsubstituted C1-C4-alkyl or represents C1-C4-alkyl, each of which is monosubstituted by a radical of the formula where R 8 for halogen, unsubstituted C 1- C4-alkyl, unsubstituted C5-C7-cycloalkyl or unsubstituted phenyl, and R 9 represents hydrogen or unsubstituted C1-C4 alkoxy, R 3 represents hydrogen, halogen, or cyano, R 4 represents hydrogen, halogen, unsubstituted C1-C4-alkyl or C1-C4-alkyl which is mono- to tri-substituted by identical or different halogen, R 5 represents hydrogen, halogen, cyano or unsubstituted C1-C4 alkoxy, R 6 stands for hydrogen, and R 7 represents hydrogen, halogen or cyano. Very particular preference is given to substituted 4-amino-6-methylbenzaldehyde derivatives of the formula (I) and their use as thermostable dyes, wherein R 1represents methyl, ethyl, n-propyl or iso-propyl, R 2 represents methyl, ethyl, n-propyl or iso-propyl or represents methyl, ethyl, n-propyl or iso-propyl, each of which is monosubstituted by a radical of the formula wherein

[0030] R 8 represents methyl, ethyl, n-propyl, iso-propyl, cyclopentyl, cyclohexyl or phenyl,

[0031] R 9 represents hydrogen, methoxy or ethoxy,

[0032] R 3 represents hydrogen, fluorine or chlorine,

[0033] R 4 represents hydrogen, fluorine, chlorine, methyl or trifluoromethyl,

[0034] R 5 represents hydrogen, fluorine, chlorine, methoxy or ethoxy,

[0035] R 6 stands for hydrogen, and

[0036] R 7 stands for hydrogen, fluorine or chlorine.

[0037] Particularly preferred are substituted 4-amino-6-methylbenzaldehyde derivatives of

[0038] Formula (I) and their use as thermostable dyes, wherein

[0039] R 1 represents methyl or ethyl,

[0040] R 2 represents methyl or ethyl or represents methyl or ethyl, each of which is monosubstituted by a radical of the formula wherein

[0041] R 8 represents methyl, ethyl, n-propyl, iso-propyl, cyclohexyl or phenyl, and

[0042] R 9 represents hydrogen or methoxy,

[0043] R 3 represents hydrogen, fluorine or chlorine,

[0044] R 4 represents hydrogen, fluorine, chlorine, or trifluoromethyl,

[0045] R 5 represents hydrogen, fluorine, chlorine or methoxy,

[0046] R 6 stands for hydrogen, and

[0047] R 7 stands for hydrogen or chlorine.

[0048] The dyes of formula (I) according to the invention can be used to achieve yellow colorations of plastics, particularly polyamides, which are surprisingly distinguished by improved lightfastness and thermal stability compared to the known yellow dyes used for these purposes. Furthermore, the dyes according to the invention meet the demand for high-quality yellow dyes absorbing in the short-wavelength spectral range.

[0049] With the substituted 4-amino-6-methylbenzaldehyde derivatives of formula (I) according to the invention, it is possible to significantly exceed the property profiles of known yellow dyes for plastic colorings that have been achieved so far.

[0050] As described above, the subject matter also relates to the use of the substituted 4-amino-6-methylbenzaldehyde derivatives of the formula (I) for the mass coloring of plastics, wherein mass coloring is understood in particular to mean processes in which the dye is incorporated into the molten plastic mass, in particular with the aid of an extruder, or in which the substituted 4-amino-6-methylbenzaldehyde derivative of the formula (I) is already added to the starting materials for producing the plastic, in particular to the monomers before polymerization.

[0051] Particularly preferred plastics are thermoplastics, most preferably vinyl polymers, polyesters, polyamides, and polyolefins, especially polyethylene and polypropylene, polycarbonates, polyamides, and polymethyl methacrylates. Polyamides, especially polyamide 6.6 and polyamide 6, are very particularly preferred.

[0052] For the purposes of this invention, the term polyamide is used to refer to synthetic, technically usable thermoplastics, thus distinguishing this class of materials from chemically related proteins. Almost all important polyamides are derived from primary amines, as the repeating unit consists of the functional group -CO-NH-. Polyamides derived from secondary amines (-CO-NR-, R = organic radical) also exist. The monomers used in the production of polyamides are primarily aminocarboxylic acids, lactams, and / or diamines and dicarboxylic acids.

[0053] Polyamide 6.6 (CAS No. 32131-17-2) is typically produced from hexamethylenediamine (HMD) and adipic acid. It is formed by polycondensation with dehydration. Polyamide 6 (CAS No. 25028-54-4) is obtained by ring-opening polymerization of ε-caprolactam with water as the initiator.

[0054] Preferred vinyl polymers are polystyrene, styrene-acrylonitrile copolymers, styrene-butadiene copolymers, styrene-butadiene-acrylonitrile terpolymers, polymethacrylate, polyvinyl chloride, etc. Preferred polyesters are polyethylene terephthalates, polybutylene terephthalates, polycarbonates and cellulose esters.

[0055] The plastics to be colored can be present individually or in mixtures with each other, as plastic masses or melts.

[0056] When used for mass coloring of plastics, the substituted 4-amino-6-methylbenzaldehyde derivatives of the formula (I) according to the invention are preferably used in finely divided form, wherein dispersants can but do not have to be used.

[0057] When used for mass coloring plastics, the substituted 4-amino-6-methylbenzaldehyde derivatives of formula (I) according to the invention can, for example, be used directly in the plastics production process after polymerization has taken place. Preferably, at least one dye (I) according to the invention is dry-mixed or ground with the plastic granules, and this mixture is plasticized and homogenized, for example, on mixing rollers or in screws. The substituted 4-amino-6-methylbenzaldehyde derivatives of formula (I) according to the invention can also be added to the molten mass and homogeneously distributed by stirring. The thus pre-colored material can then be further processed into molded parts as usual, e.g., by spinning, extrusion, or injection molding.

[0058] For the purposes of the present invention, the term “molded parts” refers to three-dimensional bodies of any spatial shape, in particular bristles, threads, fibers, films and plates.

[0059] Since the substituted 4-amino-6-methylbenzaldehyde derivatives of formula (I) according to the invention are surprisingly resistant to polymerization catalysts, especially peroxides, it is also possible to add them to the monomeric starting materials for plastics production, e.g., polymethyl methacrylate (PMMA), and then polymerize them in the presence of polymerization catalysts. For this purpose, these are preferably dissolved in the monomeric components or intimately mixed with them.

[0060] The substituted 4-amino-6-methylbenzaldehyde derivatives of the formula (I) according to the invention are preferably used for coloring the said plastics, in particular polyamide, in amounts of 0.0001 to 1 wt.%, in particular 0.01 to 0.5 wt.%, based on the amount of polymer.

[0061] By adding pigments insoluble in the polymers, especially titanium dioxide, correspondingly valuable muted colors can be obtained. In this case, titanium dioxide can be present in an amount of 0.01 to 10 wt.%, preferably 0.1 to 5 wt.%, based on the amount of polymer.

[0062] The present invention further relates to a process for the mass coloring of plastics, wherein at least one substituted 4-amino-6-methylbenzaldehyde derivative of the formula (I) is dry-mixed or ground with at least one plastic, preferably in granulate form, and this mixture is plasticized and homogenized, for example, on mixing rollers or in screws.

[0063] The substituted 4-amino-6-methylbenzaldehyde derivatives of formula (I) according to the invention can also be added to the molten mass and homogeneously distributed by stirring. It is also possible to add the substituted 4-amino-6-methylbenzaldehydes of formula (I) according to the invention to the monomeric starting materials during plastics production and subsequently polymerize them.

[0064] The material pre-colored in this way can then be further processed into molded parts, preferably by spinning into bristles, threads, etc., or by extrusion or injection molding.

[0065] These processes produce transparent or opaque brilliant yellow dyes with very good heat and thermal stability and light resistance.

[0066] To carry out such processes, mixtures of the substituted 4-amino-6-methylbenzaldehyde derivatives of the formula (I) according to the invention with other dyes and / or inorganic and / or organic pigments can also be used.

[0067] The present invention further relates to plastic compositions comprising at least one thermoplastic and at least one substituted 4-amino-6-methylbenzaldehyde derivative of the formula (I).

[0068] The plastic compositions according to the invention preferably contain at least one thermoplastic from the series vinyl polymers, polyesters, polyamides and polyolefins, particularly preferably polyethylene and polypropylene, polycarbonates, polyamides and polyacrylic methacrylate.

[0069] The plastic compositions according to the invention very particularly preferably contain at least one polyamide, in particular polyamide 6.6 and / or polyamide 6.

[0070] The plastic compositions according to the invention can also contain the thermoplastic in the form of the respective polymerizable monomers.

[0071] The plastic compositions according to the invention contain the thermoplastic in finely distributed form, preferably in the form of granules.

[0072] The plastic compositions according to the invention may contain one or more dyes, organic or inorganic pigments and conventional auxiliaries and additives in the amounts customary for these substances.

[0073] To produce muted colorations, the plastic compositions according to the invention preferably contain titanium dioxide in an amount of 0.01 to 10 wt.%, preferably 0.1 to 5 wt.%, based on the amount of thermoplastics.

[0074] The plastic compositions according to the invention can be produced in a known manner, for example by mixing or grinding at least one thermoplastic, preferably in granulate form, with at least one substituted 4-amino-6-methylbenzaldehyde derivative of the formula (I).

[0075] The present invention further relates to a process for preparing the substituted 4-amino-6-methylbenzaldehyde derivatives of formula (I) according to the invention.

[0076] The substituted 4-amino-6-methylbenzaldehyde derivatives of the formula (I) according to the invention can be prepared in a manner known per se by reacting at least one substituted 4-amino-6-methylbenzaldehyde of the formula (II) where R 1 and R 2 have the general and preferred meanings given for formula (I), with at least one phenylacetonitrile derivative of formula (III) wherein

[0077] R 3 , R 4 , R 5 , R 6 and R 7 which have the general and preferred meanings given for formula (I).

[0078] The process according to the invention for preparing the dyes of formula (I) by reacting substituted 4-amino-6-methylbenzaldehydes of formula (II) with the phenylacetonitrile derivatives of formula (III) can be carried out in a manner known per se.

[0079] In general, the process according to the invention is carried out by first initially charging the substituted 4-amino-6-methylbenzaldehyde (II) and adding the phenylacetonitrile derivative (III). After the reaction has been completed, the dye of formula (I) is isolated. Isolation can be carried out by conventional methods, preferably by filtration. The resulting reaction product can optionally be further processed by further process steps such as washing and drying.

[0080] To carry out the process according to the invention, 0.8 to 1.5 mol, preferably 0.9 to 1.1 mol and particularly preferably 1.0 mol of phenylacetonitrile derivative (III) is generally used per mole of substituted 4-amino-6-methylbenzaldehyde (II).

[0081] The process according to the invention can be carried out in the presence of at least one solvent. Suitable solvents are, for example, those from the series of alcohols and formamides. The process for preparing the dyes (I) according to the invention is preferably carried out in the presence of at least one alcohol from the series consisting of methanol, ethanol, propanol, and / or at least one formamide from the series consisting of dimethylformamide and diethylformamide, particularly preferably in the presence of methanol and / or dimethylformamide. The process according to the invention can be carried out in the presence of at least one base. Suitable bases are, for example, alkali metal hydroxides and alkali metal alkoxides. Preference is given to using lithium hydroxide, sodium hydroxide, potassium hydroxide and / or potassium tert-butoxide, particularly preferably sodium hydroxide and / or potassium tert-butoxide.

[0082] The process according to the invention is generally carried out at a temperature in the range from -10 to 180 °C, preferably from 0 to 100 °C and particularly preferably from 10 to 90 °C.

[0083] The process according to the invention is expediently carried out at ambient pressure, but the reaction can also be carried out in the range from 1000 to 10,000 hPa, preferably from 10 to 5000 hPa. Ambient pressure is understood to mean an air pressure in the range from about 925 hPa to 1070 hPa.

[0084] The phenylacetonitrile derivatives of formula (III) are known and can be obtained, for example, as commercial products from Alfa Aesar.

[0085] Preferred compounds of formula (III) for carrying out the process according to the invention are 3-(trifluoromethyl)phenylacetonitrile, 4-methoxyphenylacetonitrile, 2,6-dichlorophenylacetonitrile, 2,4-chlorophenylacetonitrile, 3,4-chlorophenylacetonitrile, 2-fluorophenylacetonitrile, 3-chlorophenylacetonitrile, 3-fluorophenylacetonitrile, 4-chlorophenylacetonitrile and 4-fluorophenylacetonitrile.

[0086] The aldehydes of formula (II) used to carry out the process according to the invention are known and can be prepared in a manner known to the person skilled in the art, for example by the Vilsmeier-Haack reaction known from the literature.

[0087] To prepare the compounds of formula (II), at least one aniline

[0088] Derivative of formula (IV) where R 1 and R 2which have the general and preferred meanings given for formula (I), with at least one formylating reagent.

[0089] In general, the reaction is carried out by initially introducing at least one compound of formula (IV) and adding the formylating reagent, optionally in the presence of at least one solvent, and then precipitating the aldehyde of formula (II) thus prepared, optionally by adding a suitable amount of a suitable precipitant, and then isolating the aldehyde of formula (II) by customary methods, for example by filtration.

[0090] A mixture of at least one formamide and at least one phosphoric acid chloride is generally used as the formylation reagent.

[0091] Preferred formamides are dimethylformamide, diethylformamide, and dibutylformamide. The preferred phosphoric acid chloride is phosphorus oxychloride.

[0092] The reaction is generally carried out at a temperature in the range between 10 and 90 °C, preferably from 20 to 80 °C and particularly preferably from 30 to 70 °C.

[0093] The process for preparing the compounds (II) is conveniently carried out at ambient pressure, but the reaction can also be carried out in the range from 1000 to 10000 hPa, preferably from 10 to 5000 hPa. Ambient pressure is understood to mean an air pressure in the range from about 925 hPa to 1070 hPa.

[0094] The reaction can be carried out in the presence of at least one solvent. Suitable solvents include formamides. Dimethylformamide and diethylformamide are preferred, with dimethylformamide being particularly preferred. When using dimethylformamide, it is particularly preferable to use it in excess, with the dimethylformamide then serving simultaneously as the formylation reagent and as the solvent.

[0095] A mixture of dimethylformamide and phosphorus oxychloride is particularly preferably used as the formylation reagent.

[0096] In general, at least one mole of formylation reagent is used per mole of compound of formula (IV), preferably 1.1 to 1.5 moles and particularly preferably 1.1 to 1.0 moles. Suitable precipitants for precipitating the compounds of formula (II) are, for example, water and alcohols such as methanol and / or ethanol. Aniline derivatives of formula (IV) are known and can be purchased as commercial products, for example from Merk, TCI, or Sigma Aldrich.

[0097] The invention is illustrated, but not limited, by the following examples.

[0098] EXAMPLES

[0099] Preparation of compounds of formula (I)

[0100] Example 1

[0101] Preparation of a compound of formula (1-1) according to the invention

[0102] 36.6 g (0.10 mol) of the aldehyde of formula (IIa) prepared according to Example A and 18.5 g (0.10 mol) of 3-(trifluoromethyl)phenylacetonitrile were added to 200 ml of methanol. The pH was then adjusted to approximately 10 with approximately 1 g of a 50% aqueous potassium hydroxide solution, and the reaction mixture was heated to 60°C and stirred for 6 hours. The mixture was then cooled to 25°C, and the reaction product was isolated on a suction filter. The filter cake was washed with approximately 300 ml of methanol and approximately 1000 ml of water at 90°C. The washed product was dried in a vacuum drying cabinet at 80°C and 20,000 Pa.

[0103] Yield: 46.9 g (corresponds to 88% of theory), melting point 101 °C.

[0104] Examples 2 to 28

[0105] The preparation and processing of the compounds of Examples 2 to 28 were carried out analogously to Example 1, but with the following deviations:

[0106] Example 2

[0107] Preparation of a compound of formula (I-2) according to the invention (1-2)

[0108] Instead of the 3-(trifluoromethyl)phenylacetonitrile used in Example 1, 14.7 g (0.10 mol) of 4-methoxyphenylacetonitrile were used.

[0109] Yield: 36.7 g (corresponding to 74% of theory), melting point 104 °C. Example 3

[0110] Preparation of a compound of formula (I-3) according to the invention

[0111] Instead of the 3-(trifluoromethyl)phenylacetonitrile used in Example 1, 18.6 g (0.10 mol) of 2,6-dichlorophenylacetonitrile were used. Yield: 37.9 g (corresponding to 71% of theory), melting point: 123 °C.

[0112] Example 4

[0113] Preparation of a compound of formula (I-4) according to the invention

[0114] Instead of the 3-(trifluoromethyl)phenylacetonitrile used in Example 1, 18.6 g (0.10 mol) of 2,4-dichlorophenylacetonitrile were used.

[0115] Yield: 36.8 g (corresponding to 69% of theory), melting point 121 °C.

[0116] Example 5

[0117] Preparation of a compound of formula (I-5) according to the invention

[0118] Instead of the 3-(trifluoromethyl)phenylacetonitrile used in Example 1, 18.6 g (0.10 mol) of 3,4-dichlorophenylacetonitrile were used.

[0119] Yield: 47.5 g (corresponding to 89% of theory), melting point 132 °C. Example 6

[0120] Preparation of a compound of formula (I-6) according to the invention

[0121] Instead of the 3-(trifluoromethyl)phenylacetonitrile used in Example 1, 13.5 g (0.10 mol) of 2-fluorophenylacetonitrile were used. Yield: 38.1 g (corresponding to 79% of theory), melting point: 107 °C.

[0122] Example 7

[0123] Preparation of a compound of formula (I-7) according to the invention

[0124] Instead of the 1-(trifluoromethyl)phenylacetonitrile used in Example 1, 15.2 g (0.10 mol) of 3-chlorophenylacetonitrile were used.

[0125] Yield: 42.4 g (corresponding to 85% of theory), melting point 111 °C. Example 8

[0126] Preparation of a compound of formula (1-8) according to the invention

[0127] Instead of the 3-(trifluoromethyl)phenylacetonitrile used in Example 1, 13.5 g (0.10 mol) of 3-fluorophenylacetonitrile were used.

[0128] Yield: 40.1 g (corresponding to 83% of theory), melting point 120 °C.

[0129] Example 9

[0130] Preparation of a compound of formula (I-9) according to the invention

[0131] Instead of the 3-(trifluoromethyl)phenylacetonitrile used in Example 1, 15.2 g (0.10 mol) of 4-chlorophenylacetonitrile were used.

[0132] Yield: 41.4 g (corresponds to 83% of theory), melting point 126 °C.

[0133] Example 10

[0134] Preparation of a compound of formula (1-10) according to the invention Instead of the 3-(trifluoromethyl)phenylacetonitrile used in Example 1, 13.5 g (0.10 mol) of 4-fluorophenylacetonitrile were used.

[0135] Yield: 37.6 g (corresponding to 78% of theory), melting point 133 °C.

[0136] Example 11 Preparation of a compound of formula (1-11) according to the invention

[0137] Instead of the aldehyde of formula (II-a) used in Example 1, 16.3 g (0.1 mol of the aldehyde of formula (II-b) prepared according to Example B) were used.

[0138] Yield: 29.4 g (corresponding to 89% of theory), melting point 123°C. Example 12

[0139] Preparation of a compound of formula (1-12) according to the invention

[0140] Instead of the aldehyde used in Example 1, 16.3 g (0.1 mol) of the aldehyde of formula (II-b) prepared according to Example B) were used and instead of (trifluoromethyl)phenylacetonitrile, 14.7 g (0.1 mol) of 4-methoxyphenylacetonitrile were used.

[0141] Yield: 22.2 g (corresponding to 76% of theory), melting point 166 °C.

[0142] Example 13

[0143] Preparation of a compound of formula (1-13) according to the invention

[0144] Instead of the aldehyde used in Example 1, 16.3 g (0.1 mol) of the aldehyde of formula (II-b) prepared according to Example B) were used and instead of 3-(trifluoromethyl)phenylacetonitrile, 18.6 g (0.1 mol) of 2,4-dichlorophenylacetonitrile were used.

[0145] Yield: 23.8 g (corresponding to 72% of theory), melting point 129 °C.

[0146] Example 14

[0147] Preparation of a compound of formula (1-14) according to the invention

[0148] Instead of the aldehyde used in Example 1, 16.3 g (0.1 mol) of the aldehyde of formula (II-b) prepared according to Example B) were used and instead of 3-(trifluoromethyl)phenylacetonitrile, 18.6 g (0.1 mol) of 3,4-dichlorophenylacetonitrile were used.

[0149] Yield: 26.8 g (corresponding to 81% of theory), melting point 155 °C.

[0150] Example 15

[0151] Preparation of a compound of formula (1-15) according to the invention

[0152] Instead of the aldehyde used in Example 1, 16.3 g (0.1 mol) of the

[0153] Example B) prepared aldehyde of formula (ll-b) and instead of 3-(trifluoromethyl)phenylacetonitrile, 13.5 g (0.1 mol) of 2-fluorophenylacetonitrile were used.

[0154] Yield: 22.4 g (corresponds to 80% of theory), melting point 122 °C.

[0155] Example 16

[0156] Preparation of a compound of formula (1-16) according to the invention

[0157] Instead of the aldehyde used in Example 1, 16.3 g (0.1 mol) of the aldehyde of formula (II-b) prepared according to Example B) were used and instead of 3-(trifluoromethyl)phenylacetonitrile, 15.2 g (0.1 mol) of 3-chlorophenylacetonitrile were used.

[0158] Yield: 23.7 g (corresponds to 80% of theory), melting point 107 °C.

[0159] Example 17

[0160] Preparation of a compound of formula (1-17) according to the invention

[0161] Instead of the aldehyde used in Example 1, 16.3 g (0.1 mol) of the aldehyde of formula (II-b) prepared according to Example B) were used and instead of 3-(trifluoromethyl)phenylacetonitrile, 13.5 g (0.1 mol) of 3-fluorophenylacetonitrile were used.

[0162] Yield: 21.0 g (corresponds to 75% of theory), melting point 115 °C.

[0163] Example 18

[0164] Preparation of a compound of formula (1-18) according to the invention

[0165]

[0166] Instead of the aldehyde used in Example 1, 16.3 g (0.1 mol) of the aldehyde of formula (II-b) prepared according to Example B) were used and instead of 3-(trifluoromethyl)phenylacetonitrile, 15.2 g (0.1 mol) of 4-chlorophenylacetonitrile were used.

[0167] Yield: 25.2 g (corresponding to 85% of theory), melting point 146 °C.

[0168] Example 19

[0169] Preparation of a compound of formula (1-19) according to the invention

[0170] Instead of the aldehyde used in Example 1, 16.3 g (0.1 mol) of the aldehyde of formula (II-b) prepared according to Example B) were used and instead of 3-(trifluoromethyl)phenylacetonitrile, 13.5 g (0.1 mol) of 4-fluorophenylacetonitrile were used.

[0171] Yield: 23.0 g (corresponding to 82% of theory), melting point 136 °C.

[0172] Example 20

[0173] Preparation of a compound of formula (I-20) according to the invention Instead of the aldehyde used in Example 1, 19.1 g (0.1 mol) of the aldehyde of formula (II-c) prepared according to Example C) were used.

[0174] Yield: 30.5 g (corresponds to 85% of theory), melting point 124 °C.

[0175] Example 21

[0176] Preparation of a compound of formula (1-21) according to the invention

[0177] Instead of the aldehyde used in Example 1, 19.1 g (0.1 mol) of the aldehyde of formula (II-c) prepared according to Example C) and 14.7 g (0.1 mol) of 4-methoxyphenylacetonitrile were used.

[0178] Yield: 24.0 g (corresponds to 75% of theory), melting point 103 °C.

[0179] Example 22

[0180] Preparation of a compound of formula (I-22) according to the invention

[0181] Instead of the aldehyde used in Example 1, 19.1 g (0.1 mol) of the aldehyde of formula (II-c) prepared according to Example C) and 18.6 g (0.1 mol) of 2,4-dichlorophenylacetonitrile were used.

[0182] Yield: 25.2 g (corresponds to 70% of theory), melting point 83 °C.

[0183] Example 23

[0184] Preparation of a compound of formula (I-23) according to the invention

[0185] Instead of the aldehyde used in Example 1, 19.1 g (0.1 mol) of the aldehyde of formula (II-c) prepared according to Example C) and 18.6 g (0.1 mol) of 3,4-dichlorophenylacetonitrile were used. Yield: 28.4 g (corresponding to 79% of theory), melting point: 146 °C

[0186] Example 24

[0187] Preparation of a compound of formula (I-24) according to the invention

[0188] Instead of the aldehyde used in Example 1, 19.1 g (0.1 mol) of the aldehyde of formula (II-c) prepared according to Example C) and 13.5 g (0.1 mol) of 2-fluorophenylacetonitrile were used.

[0189] Yield: 23.7 g (corresponds to 77% of theory), melting point 82 °C

[0190] Example 25

[0191] Preparation of a compound of formula (I-25) according to the invention

[0192] Instead of the aldehyde used in Example 1, 19.1 g (0.1 mol) of the aldehyde of formula (II-c) prepared according to Example C) and 15.2 g (0.1 mol) of 3-chlorophenylacetonitrile were used. Yield: 25.3 g (corresponding to 78% of theory), melting point: 102 °C

[0193] Preparation of a compound of formula (I-26) according to the invention

[0194] Instead of the aldehyde used in Example 1, 19.1 g (0.1 mol) of the aldehyde of formula (II-c) prepared according to Example C) and 13.5 g (0.1 mol) of 3-fluorophenylacetonitrile were used.

[0195] Yield: 22.2 g (corresponds to 72% of theory), melting point 122 °C

[0196] Example 27

[0197] Preparation of a compound of formula (1-27) according to the invention

[0198] Instead of the aldehyde used in Example 1, 19.1 g (0.1 mol) of the aldehyde of formula (II-c) prepared according to Example C) and 15.2 g (0.1 mol) of 4-chlorophenylacetonitrile were used.

[0199] Yield: 27.0 g (corresponding to 83% of theory), melting point 137 °C.

[0200] Example 28

[0201] Preparation of a compound of formula (I-28) according to the invention Instead of the aldehyde used in Example 1, 19.1 g (0.1 mol) of the aldehyde of formula (II-c) prepared according to Example C) and 13.5 g (0.1 mol) of 4-fluorophenylacetonitrile were used. Yield: 25.3 g (corresponding to 82% of theory), melting point: 113 °C.

[0202] Example 29

[0203] Preparation of a compound of formula (1-29) according to the invention

[0204] Instead of the aldehyde used in Example 1, 29.7 g (0.1 mol) of the aldehyde of formula (II-d) prepared according to Example D) and 15.2 g (0.1 mol) of 4-chlorophenylacetonitrile were used.

[0205] Yield: 37.1 g (corresponding to 86% of theory), melting point 93 °C.

[0206] Example 30

[0207] Preparation of a compound of formula (I-30) according to the invention

[0208] Instead of the aldehyde used in Example 1, 32.6 g (0.1 mol) of the aldehyde of formula (II-e) prepared according to Example E) and 15.2 g (0.1 mol) of 4-chlorophenylacetonitrile were used.

[0209] Yield: 39.5 g (corresponding to 86% of theory), melting point 107 °C. Example 31

[0210] Preparation of a compound of formula (1-31) according to the invention

[0211] Instead of the aldehyde used in Example 1, 34.1 g (0.1 mol) of the aldehyde of formula (II-f) prepared according to Example F) and 15.2 g (0.1 mol) of 4-chlorophenylacetonitrile were used.

[0212] Yield: 41.2 g (corresponds to 87% of theory), melting point 85 °C.

[0213] Example 32

[0214] Preparation of a compound of formula (I-32) according to the invention

[0215] Instead of the aldehyde used in Example 1, 36.0 g (0.1 mol) of the aldehyde of formula (II-g) prepared according to Example G) and 15.2 g (0.1 mol) of 4-chlorophenylacetonitrile were used.

[0216] Yield: 44.5 g (corresponding to 85% of theory), melting point 88 °C. Preparation of the precursors

[0217] Example A Preparation of an aldehyde of formula (ll-a) a) Preparation of the ether

[0218] 176.3 g (1.0 mol) of 4-cyclohexylphenol and 197.7 g (1.0 mol) of N-(2-chloroethyl)-N-ethyl-3-methylaniline were added to 500 ml of water. Then, 84 g (1.05 mol) of a 50% aqueous sodium hydroxide solution were added. The mixture was then heated to 95 °C over 180 minutes, and then stirred for 12 hours. The reaction mixture was then allowed to stand for 4 hours until phase separation occurred. The aqueous phase was then separated. Residual water was removed from the organic phase under vacuum at 80 °C and 2000 Pa. b) Preparation of the aldehyde

[0219] Subsequently, 310 g (4.24 mol) of dimethylformamide were added dropwise to the organic phase from step a). Then, over the course of 3 hours at 60 °C, 160 g (1.04 mol) of phosphorus oxychloride were added. The reaction mixture was stirred for 5 hours. It was then cooled to 20 °C, and 160 g of methanol and 400 g of water were added. A pH of approximately 8 was adjusted by adding a 50% aqueous sodium hydroxide solution. The reaction mixture was allowed to stand for 4 hours until phase separation had occurred. The aqueous phase was then separated. Residual water was removed from the organic phase under vacuum at 80 °C and 2000 Pa.

[0220] Yield: 347.2 g (corresponds to 95% of theory).

[0221] Example B

[0222] Preparation of an aldehyde of formula (ll-b)

[0223] 310 g (4.24 mol) of dimethylformamide were initially introduced, to which 135.2 g (1.0 mol) of N,N-dimethyl-3-methylaniline were added dropwise. 160 g (1.04 mol) of phosphorus oxychloride were then added at 60 °C over the course of 3 hours. The reaction mixture was stirred for 5 hours. The mixture was then cooled to 20 °C, and 160 g of methanol and 400 g of water were added. A pH of approximately 8 was then adjusted by adding a 50% aqueous sodium hydroxide solution. The reaction mixture was left to stand for 4 hours until phase separation had occurred. The aqueous phase was then separated off. Residual water was removed from the organic phase under vacuum at 80 °C and 2000 Pa.

[0224] Yield: 150.1 g (corresponds to 92% of theory).

[0225] Example C

[0226] Preparation of an aldehyde of formula (ll-c)

[0227] 310 g (4.24 mol) of dimethylformamide were initially charged, to which 163.5 g (1.0 mol) of N,N-diethyl-3-methylaniline were added dropwise. Then, at 60 °C, 160 g (1.04 mol) of phosphorus oxychloride were added over the course of 3 hours. The reaction mixture was stirred for 5 hours. The mixture was then cooled to 20 °C, and 160 g of methanol and 400 g of water were added. A pH of approximately 8 was then adjusted using approximately 240 g of a 50% aqueous sodium hydroxide solution. The reaction mixture was left to stand for 4 hours until phase separation had occurred. The aqueous phase was then separated off. Residual water was removed from the organic phase under vacuum at 80 °C and 2000 Pa.

[0228] Yield: 177.1 g (corresponds to 93% of theory).

[0229] Example D

[0230] Preparation of an aldehyde of formula (ll-d)

[0231] a) Preparation of the ether

[0232] 500 ml of water were initially charged, and 108.1 g (1.0 mol) of p-phenylphenol and 197.7 g (1.0 mol) of N-(2-chloroethyl)-N-ethyl-3-methylaniline were added. Then, 84 g (1.05 mol) of a 50% aqueous sodium hydroxide solution were added. The reaction mixture was then heated to 95 °C over 180 minutes, and then stirred for 12 hours. The reaction mixture was then allowed to stand for 4 hours until phase separation occurred. The aqueous phase was then separated. Residual water was removed from the organic phase under vacuum at 80 °C and 2000 Pa. b) Preparation of the aldehyde

[0233] 310 g (4.24 mol) of dimethylformamide were added dropwise to the organic phase from step a). 160 g (1.04 mol) of phosphorus oxychloride were then added over the course of 3 hours at 60 °C. The reaction mixture was stirred for 5 hours. The mixture was then cooled to 20 °C, and 160 g of methanol and 400 g of water were added. A pH of approximately 8 was then adjusted by adding a 50% aqueous sodium hydroxide solution. The reaction mixture was allowed to stand for 4 hours until phase separation had occurred. The aqueous phase was then separated. Residual water was removed from the organic phase under vacuum at 80 °C and 2000 Pa.

[0234] Yield: 279.6 g (corresponds to 94% of theory)

[0235] Example E

[0236] Preparation of an aldehyde of formula (I le)

[0237] a) Preparation of the ether

[0238] 500 ml of water were initially charged, and 136.2 g (1.0 mol) of 2-isopropylphenol and 197.7 g (1.0 mol) of N-(2-chloroethyl)-N-ethyl-3-methylaniline were added. Then, 84 g (1.05 mol) of a 50% aqueous sodium hydroxide solution were added. The reaction mixture was then heated to 95 °C over 180 minutes, and then stirred for 12 hours. The reaction mixture was then allowed to stand for 4 hours until phase separation occurred. The aqueous phase was then separated. Residual water was removed from the organic phase under vacuum at 80 °C and 2000 Pa. b) Preparation of the aldehyde:

[0239] 310 g (4.24 mol) of dimethylformamide were added dropwise to the organic phase from step a). 160 g (1.04 mol) of phosphorus oxychloride were then added over the course of 3 hours at 60°C. The reaction mixture was stirred for 5 hours. The mixture was then cooled to 20°C, and 160 g of methanol and 400 g of water were added. A pH of approximately 8 was then adjusted by adding a 50% aqueous sodium hydroxide solution. The reaction mixture was allowed to stand for 4 hours until phase separation had occurred. The aqueous phase was then separated. Residual water was removed from the organic phase under vacuum at 80°C and 2000 Pa.

[0240] Yield: 309.2 g (corresponds to 95% of theory).

[0241] Example F

[0242] Preparation of an aldehyde of formula (ll-f)

[0243] a) Preparation of the ether

[0244] 500 ml of water were initially charged, and 152.2 g (1.0 mol) of 2-methoxy-4-ethylphenol and 197.7 g (1.0 mol) of N-(2-chloroethyl)-N-ethyl-3-methylaniline were added. Then, 84 g (1.05 mol) of a 50% aqueous sodium hydroxide solution were added. The reaction mixture was then heated to 95 °C over 180 minutes, and then stirred for 12 hours. The reaction mixture was then allowed to stand for 4 hours until phase separation occurred. The aqueous phase was then separated. Residual water was removed from the organic phase under vacuum at 80 °C and 2000 Pa. b) Preparation of the aldehyde

[0245] 310 g (4.24 mol) of dimethylformamide were added dropwise to the organic phase obtained in step a). 160 g (1.04 mol) of phosphorus oxychloride were then added over the course of 3 hours at 60°C. The reaction mixture was stirred for 5 hours. The mixture was then cooled to 20°C, and 160 g of methanol and 400 g of water were added. A pH of approximately 8 was then adjusted by adding a 50% aqueous sodium hydroxide solution. The reaction mixture was allowed to stand for 4 hours until phase separation had occurred. The aqueous phase was then separated. Residual water was removed from the organic phase under vacuum at 80°C and 2000 Pa.

[0246] Yield: 324.3 g (corresponds to 95% of theory).

[0247] Preparation of an aldehyde of formula (ll-g)

[0248] a) Preparation of the ether

[0249] 500 ml of water were initially charged, and 170.2 g (1.0 mol) of 4-phenylphenol and 197.7 g (1.0 mol) of N-(2-chloroethyl)-N-ethyl-3-methylaniline were added. Then, 84 g (1.05 mol) of a 50% aqueous sodium hydroxide solution were added. The reaction mixture was then heated to 95 °C over 180 minutes, and then stirred for 12 hours. The reaction mixture was then allowed to stand for 4 hours until phase separation occurred. The aqueous phase was then separated. Residual water was removed from the organic phase under vacuum at 80 °C and 2000 Pa. b) Preparation of the aldehyde

[0250] Then 310 g (4.24 mol) of dimethylformamide were added dropwise to the organic phase from step a). Then 160 g (1.04 mol) of phosphorus oxychloride were metered in over the course of 3 hours at a temperature of 60 °C. The reaction mixture was stirred for 5 hours. It was then cooled to 20 °C and mixed with 160 g of methanol and 400 g of water. A pH of approximately 8 was then adjusted by adding a 50% aqueous sodium hydroxide solution. The reaction mixture was stirred for 2 hours. The reaction product was then isolated on a suction filter at 20 °C. The filter cake was washed with approximately 300 ml of methanol and approximately 1000 ml of water at a temperature of 50 °C. The washed product was dried in a vacuum drying oven at a temperature of 80 °C and a pressure of 20,000 Pa.

[0251] Yield: 341.5 g (corresponds to 95% of theory). List of purchased raw materials.-

[0252] Spectroscopic measurements

[0253] The results of the UVA / IS measurements and absorbance values ​​for the compounds according to the invention of Examples 1 to 32 are listed in Table 1.

[0254] Table 1 ) The UV / VIS absorption spectra of the compounds according to the invention were all determined in

[0255] Solvent 1-methoxy-2-propyl acetate (CAS No. 108-65-6) was measured. 2) The given E1 / 1 value is a fictitious extinction value that would be obtained if a 1 weight percent solution of the respective compound (dissolved in 1-methoxy-2-propyl acetate) were measured in a cuvette with a path length of 1 cm.

[0256] Application-related results

[0257] Description of the test method “Thermostability”

[0258] In a tumbler mixer, 2 g of the dye to be tested were mixed with 1998 g of a PA6 granulate of the type Durethan B30S (commercial product of Lanxess Deutschland GmbH) containing 1% TiO2, which had been dried for 4 hours at 80 °C. This mixture was extruded at a maximum melt temperature of 240 °C on a single-screw extruder (Stork, 25 mm screw), cooled with water, granulated using a Sheer granulator, and dried for 8 hours at 80 °C. The heat stability of the resulting plastic granules was tested on an injection molding machine according to DIN EN 12877-2 ("Determination of the resistance of the color to heat during processing of colorants in plastics") (Method A). As a standard, a sample was produced at 240 °C with a residence time in the screw of 2.5 minutes. The samples to be determined were coloristically evaluated against this standard sample, which were prepared at a residence time of 5 minutes and temperatures of 240-320 °C.Samples with a total color deviation of DE < 3.0 were considered stable at the applied temperature.

[0259] The results of the determination of the thermal stability of the compounds according to the invention of Examples 1 to 32 as well as those of the non-inventive compounds of the prior art are shown in Table 2.

[0260] Table 2

[0261] Conclusion:

[0262] As can be seen from Table 2, the dyes according to the invention have a significantly increased heat or thermal stability compared to the heat or thermal stability of the prior art dyes used for plastic coloring.

Claims

Substituted 4-amino-6-methylbenzaldehyde derivatives of formula (I) characterized in that R 1 represents methyl or ethyl, R 2 represents methyl or ethyl, or represents methyl or ethyl, each of which is monosubstituted by a radical of the formula wherein R 8 represents methyl, ethyl, n-propyl, iso-propyl, cyclohexyl or phenyl, and R 9 represents hydrogen or methoxy, R 3 represents hydrogen, fluorine or chlorine, R 4 represents hydrogen, fluorine, chlorine, or trifluoromethyl, R 5 represents hydrogen, fluorine, chlorine or methoxy, R 6 stands for hydrogen, and R 7represents hydrogen or chlorine. Substituted 4-amino-6-methylbenzaldehyde derivatives according to claim 1, characterized in that they are one of the formulas (I-1) to (I-32) 3. Use of substituted 4-amino-6-methylbenzaldehyde derivatives of formula (I) wherein R 1 represents methyl or ethyl, R 2 represents methyl or ethyl, or represents methyl or ethyl, each of which is monosubstituted by a radical of the formula wherein R 8 represents methyl, ethyl, n-propyl, iso-propyl, cyclohexyl or phenyl, and R 9 represents hydrogen or methoxy, R 3 represents hydrogen, fluorine or chlorine, R 4represents hydrogen, fluorine, chlorine, or trifluoromethyl, R 5 represents hydrogen, fluorine, chlorine or methoxy, R 6 stands for hydrogen, and R 7 stands for hydrogen or chlorine, as thermostable methine dyes in plastics or polymers, with the proviso that “thermostable” means a heat stability of > 385 °C to be determined on the respective plastic granulate according to DIN EN 12877-2 Method A.

4. Use according to claim 3, characterized in that the substituted 4-amino-6-methylbenzaldehyde derivatives of formula (I) are one of the formulas (I-1) to (I-32) 5. Use according to claim 3 or 4, characterized in that the substituted 4-amino-6-methylbenzaldehyde derivatives of the formula (I) for used for mass coloring of plastics.

6. Use according to claim 5, characterized in that the plastics are thermoplastics.

7. Use according to claim 5 or 6, characterized in that the plastics are from the series vinyl polymers, polyesters, polyolefins, polycarbonates, polyamides or polymethyl methacrylates or mixtures thereof.

8. Use according to claim 7, characterized in that the polyamides are polyamide 6 or polyamide 6.

6.

9. Use according to one or more of claims 5 to 8, characterized in that the substituted 4-amino-6-methylbenzaldehyde derivative of the formula (I) is used in an amount of 0.0001 to 1 percent by weight, in particular 0.01 to 0.5 percent by weight, based on the amount of plastic.

10. Use according to one or more of claims 5 to 9, characterized in that during mass coloring, the substituted 4-amino-6-methylbenzaldehyde derivative of the formula (I) is dry-mixed or ground with at least one plastic, preferably in granulate form, and this mixture is melted and homogenized.

11. A process for the mass coloring of plastics, characterized in that at least one substituted 4-amino-6-methylbenzaldehyde derivative of the formula (I) according to at least one of claims 1 or 2 is dry-mixed or ground with at least one plastic, preferably in granulate form, and this mixture is melted and homogenized.

12. A process for the mass coloring of plastics, characterized in that at least one substituted 4-amino-6-methylbenzaldehyde derivative of the formula (I) according to at least one of claims 1 or 2 is added to a molten plastic mass containing at least one plastic and the mass is then homogenized.

13. A process for the mass coloring of plastics, characterized in that at least one substituted 4-amino-6-methylbenzaldehyde derivative of the formula (I) according to at least one of claims 1 or 2 is mixed with the monomeric starting materials to produce at least one plastic and the mixture is subsequently polymerized.

14. A plastic composition, in particular a polyamide composition or polymethyl methacrylate composition, characterized in that it contains at least one substituted 4-amino-6-methylbenzaldehyde derivative of the formula (I) according to at least one of claims 1 or 2.

15. Molded parts, characterized in that they contain at least one plastic composition according to claim 14.

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