Method for coloring thermoplastic polymers - Patent Application 20070122997

Abstract

The present invention relates to a method for producing a colored molding composition having an improved optical appearance and particularly high thermal stability. Furthermore, the present invention relates to injection molded and extruded parts comprised of said colored molding composition.

Description

[Technical Field]

[0001] The present invention relates to a method for producing a colored molding composition having an improved optical appearance and particularly high thermal stability, and to a colored molding composition obtainable by the method of the present invention, and further to injection-molded and extruded parts composed of said colored molding composition.

[0002] prior art Transparent thermoplastic polymers, such as polymethyl methacrylate (PMMA), polyesters, polycarbonates, and polyamides, are commonly colored various colors using soluble organic dyes. Perinone-, azo-, and anthraquinone-type dyes are typically used for this purpose due to their commercial availability and bright colors. As used herein, the term "soluble" indicates that the dye is soluble in the matrix of the thermoplastic polymer in the amount used to color it. Thus, as used herein, the term "colored molding composition" refers to a thermoplastic composition containing an organic dye uniformly distributed in the matrix of the thermoplastic polymer.

[0003] For example, WO 2012 / 080397 describes a polymer composition comprising a transparent thermoplastic material, such as polycarbonate, and a combination of various colorants, notably perinone dyes.

[0004] WO 2015 / 036526 teaches a thermoplastic molding composition comprising a styrene copolymer, a carbon black pigment, and at least three dyes soluble in the molding composition. This document also suggests the use of perinone dyes.

[0005] JP 2016-037518 A describes a molded part made of a methacrylic resin composition that exhibits a jet black color equivalent to that of a coated part while maintaining its weather resistance and opacity. The composition typically contains three or more dyes selected from the group consisting of red, yellow, green, blue, and purple dyes.

[0006] Soluble monoazo dyes, especially those containing at least one heteroaromatic moiety, have been used to color transparent thermoplastic polymers such as PMMA due to their excellent color brightness and high weathering stability (Plastics Additives, an AZ Reference, G. Pritchard et al., Springer, 1998). International Publication Nos. 2010 / 020474 and 2012 / 004257 describe methods for coloring thermoplastic polymers such as PMMA with such dyes. Examples in International Publication Nos. 2010 / 020474 and 2012 / 004257 disclose the use of commercially available dyes, Thermoplast® Red 454 (CI Solvent Red 195) and Macrolex® Yellow G (CI Solvent Yellow 114), to color PLEXIGLAS® 8N. Corresponding dyes are commercially available from various manufacturers in the form of colored preparations. Such preparations essentially consist of the corresponding monoazo dyes of varying chemical purity. The added auxiliaries extend the shelf life of the color preparations and improve their use by the customer.

[0007] Commercially available monoazo dyes containing at least one heteroaromatic moiety offer many advantages, but their use in coloring polymers such as PMMA has been limited to date. One major reason is the common observation that such dyes often have only moderate thermal stability and suffer from the undesirable formation of dark particles at the processing temperatures and conditions of thermoplastic polymers. In some cases, such dark particles are formed already during blending or production of the colored molding composition. In other cases, dark particle formation can occur unexpectedly during the production of parts with complex geometries by injection molding when PMMA colored with monoazo dyes is utilized.

[0008] The poor thermal stability of colored molding compositions often leads to undesirable discoloration when exposed to elevated temperatures.Therefore, the thermal stability of a given molding composition can often be estimated by measuring the color of a sample of this molding composition in the CIELAB color space before and after it is exposed to high temperatures.Color difference, that is, the difference between these two colors, can serve as an indicator of thermal stability.In addition, the poor thermal stability of colored preparations that contain monoazo dyes can lead to undesirable contamination and the formation of black particles in colored moldings, for example, when exposed to high temperatures during their processing.

[0009] Object of the invention It is therefore an object of the present invention to provide a method for producing a heat-stable colored molding composition comprising a thermoplastic polymer and a monoazo dye containing at least one heteroaromatic moiety. In particular, it is desirable that the molding composition have excellent optical properties and remain substantially free of undesirable dark particles even when exposed to high temperatures and / or high shear forces, for example, during injection molding of parts having complex geometries.

[0010] Another object of the present invention was to provide a colored molding composition having excellent optical properties and high thermal and weathering stability.Finally, the present invention aims to provide colored molded parts, especially colored molded parts having complex geometric shapes, that have these advantageous properties.

[0011] Summary of the Invention The present invention is based on the surprising discovery that the formation of undesirable dark particles in molding compositions containing monoazo dyes with at least one heteroaromatic moiety can be effectively prevented by using a coloring preparation containing less than 100 ppm of aluminum compounds and less than 300 ppm of silicon compounds.The monoazo dyes with at least one heteroaromatic moiety have excellent solubility in the thermoplastic polymers used, so they dissolve completely and uniformly in the polymer matrix, and the resulting colored molding compositions have excellent optical properties and low haze.

[0012] As used in this application, the term "color preparation" refers to a material commercially available from a manufacturer as a "dye." The color preparation essentially consists of the corresponding monoazo dye with varying chemical purity and, optionally, an added dispersant. Typically, such commercially available dyes exhibit various amounts of several metal ions, such as aluminum and silicon. Furthermore, different batches of such commercially available dyes often exhibit varying metal contents. Typically, only the amounts of harmful metals, such as cadmium, mercury, and chromium, are specified and limited.

[0013] Without wishing to be bound by theory, the inventors have discovered that aluminum and silicon compounds, even when present in low amounts of several hundred ppm, can form chelate-type chemical complexes with monoazo dyes containing at least one heteroaromatic moiety. In contrast to free monoazo dyes, these chemical complexes are substantially insoluble in thermoplastic polymer matrices, resulting in the undesirable formation of dark particles in the resulting molded parts. In particular, when molded parts with complex geometries are produced by injection molding, high temperatures are often required to ensure a sufficiently low viscosity of the polymer melt. It is believed that the high temperatures combined with the high shear forces during the injection molding process promote the formation of such undesirable dark particles in the presence of aluminum or silicon.

[0014] Thus, in a first aspect, the present invention provides a method for producing a colored molding composition, comprising: a) providing a thermoplastic polymer; b) adding a colorant preparation or a liquid composition or masterbatch comprising said colorant preparation to the thermoplastic polymer from step a); Including, the color preparation comprises a monoazo dye containing at least one heteroaromatic moiety; The coloring preparation contains less than 100 ppm, preferably less than 50 ppm, of aluminum or its compounds and less than 300 ppm, preferably less than 200 ppm, of silicon or its compounds; Target methods.

[0015] The amounts of aluminum and silicon are given above as ppm by weight, based on the total weight of the color preparation. For example, the aluminum and silicon content given in ppm refers to mg of aluminum or silicon based on 1 kg of color preparation.

[0016] The aluminum and silicon content in the color preparation can be readily determined by methods such as atomic emission spectrometry. For example, a sample can be digested and mineralized using a microwave pressure digestion system, the MARS5 PLUS / MARS6, and then analyzed using an iCAP™ 7400 ICP-OES analyzer, an atomic emission spectrometer available from ThermoFischer Scientific.

[0017] According to the present invention, the selection of an appropriate coloring preparation having a specific aluminum and silicon content results in an advantageous colored molding composition obtained by the method of the present invention, which colored molding composition exhibits high thermal stability and / or low formation of dark particles. If necessary, the chemical purity of the coloring preparation containing a monoazo dye (e.g., a commercially available dye) can be improved before use, typically by known purification steps such as crystallization, recrystallization, chromatography, solid-phase extraction.

[0018] Preferably, the method of the present invention includes providing a color preparation comprising a monoazo dye, the color preparation containing less than 100 ppm aluminum and less than 300 ppm silicon, and the color preparation can be obtained, if necessary, by one or more purification steps, such as crystallization, recrystallization, chromatography, solid phase extraction.

[0019] In particular, the method of the present invention for producing a colored molding composition includes providing a color preparation containing less than 100 ppm, preferably less than 50 ppm, of aluminum or its compounds and less than 300 ppm, preferably less than 200 ppm, of silicon or its compounds.Preferably, providing a color preparation includes determining the aluminum and silicon content in the color preparation, for example, by digestion and wet chemical or spectroscopic (for example, atomic emission spectroscopy) determination of aluminum and silicon, optionally purifying the color preparation, and selecting a suitable color preparation containing less than 100 ppm, preferably less than 50 ppm, of aluminum or its compounds and less than 300 ppm, preferably less than 200 ppm, of silicon or its compounds.

[0020] The coloring preparation used in this method has a particularly low content of aluminum or its compounds and silicon or its compounds, so that the liquid composition or masterbatch containing it also usually contains less than 100 ppm, preferably less than 50 ppm, of aluminum or its compounds and less than 300 ppm, preferably less than 200 ppm, of silicon or its compounds.Again, the aluminum and silicon contents in the liquid composition or masterbatch can be determined by methods such as atomic absorption spectrometry.

[0021] In addition, the present invention provides a colored molding composition comprising a thermoplastic polymer and a monoazo dye, and a method for producing molded or extruded parts by using the same.The colored preparation used in this method has a particularly low content of aluminum or its compounds and silicon or its compounds, so that the colored molding composition typically contains less than 100 ppm, preferably less than 50 ppm, of aluminum or its compounds and less than 300 ppm, preferably less than 200 ppm, of silicon or its compounds, as determined by atomic absorption spectrometry.

[0022] Detailed Description The monoazo dyes for use in the present invention are themselves well known to those skilled in the art and are derivatives of diazene(diimide) HN=NH, where both hydrogens are replaced by aromatic or heteroaromatic moieties (IUPAC Recommendations 1995, published in Pure & Appl. Chem., Vol. 67, No. 819, pp. 1307-1375, 1995). That is, the chemical structure of all monoazo dyes contains one chemical moiety, -N=N-.

[0023] As used herein, the term "heteroaromatic moiety" is well-known and typically refers to a 5- or 6-membered aromatic moiety containing at least one heteroatom in its structure. Typically, the heteroatom is an N, O, S, Se, or Te atom, more preferably an N, O, or S atom, and even more preferably an N atom. Specific examples of heteroaromatic moieties include, for example, furan, thiophene, pyran, pyrrole, imidazole, pyrazole, 3H-pyrazol-3-one, pyrazolin-5-one, pyridine, pyrazine, pyrimidine, pyridazine, thiazole, oxazole, isothiazole, isoxazole, thiadiazole, oxadiazole, triazole, selenazole, and tellurazole. Further examples of heteroaromatic moieties include, for example, indolizine, purine, pteridine, carboline, pyrroloimidazole, pyrrolotriazole, pyrazoloimidazole, pyrazolotriazole, pyrazolopyrimidine, pyrazolotriazine, triazolopyridine, tetraazaindene, imidazoimidazole, imidazopyridine, imidazopyrazine, imidazopyrimidine, imidazopyridazine, oxazolopyridine, oxazolopyrazine, oxazolopyrimidine, oxazolopyridazine, thiazolopyridine, thiazolopyrazine, thiazolopyrimidine, thiazolopyridazine, pyridinopyrazine, pyrazinopyrazine, pyrazinopyridazine, naphthyridine, imidazotriazine, and 1H-perimidine.

[0024] The heteroaromatic moiety is typically substituted with one or more substituents, which may be alkyl, alkenyl, alkynyl, aryl, amino, alkoxyl, aryloxy, acyl, alkoxycarbonyl, aryloxycarbonyl, acyloxy, acylamino, alkoxycarbonylamino, aryloxycarbonylamino, sulfonylamino, sulfamoyl, -carbamoyl, alkylthio, arylthio, sulfonyl, cyano, and heterocyclic groups and halogen atoms. Alkyl, alkenyl, aryl, alkoxyl, aryloxy, cyano, and heterocyclic groups and halogen atoms are more preferred, and even more preferred are alkyl, aryl, alkoxyl, aryloxy, and aromatic heterocyclic groups, with alkyl, aryl, alkoxyl, and aromatic heterocyclic groups being particularly preferred.

[0025] Specific examples of monoazo dyes for use in the present invention include Disperse Yellow 241 (5-[(3,4-dichlorophenyl)azo]-1,2-dihydro-6-hydroxy-1,4-dimethyl-2-oxonicotinonitrile), Solvent Black 3 (2,3-dihydro-2,2-dimethyl-6-((4-(phenylazo)-1-naphthyl)azo)-1H-perimidine), Solvent Red 195 (cyano-5-[[5-cyano-2,6-bis[(3-methoxypropyl)amino]-4-methylpyridin-3-yl]azo]-3-methyl-2-thiophenecarboxylic acid methyl ester), Solvent Yellow 16 (5-methyl-2-phenyl-4-phenylazo-4H-pyrazol-3-one), Solvent Solvent Yellow 18 (4-[(2,4-dimethylphenyl)azo]-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-one), Solvent Yellow 21 (3-[(1-oxonaphthalen-2-ylidene)methylhydrazinylidene]-1-prop-2-enylindol-2-one), Solvent Yellow 72 (4-((o-methoxyphenyl)azo)-3-methyl-1-phenyl-2-pyrazolin-5-one), Solvent Yellow 82, Solvent Yellow 16 (5-methyl-2-phenyl-4-phenylazo-4H-pyrazol-3-one).

[0026] In a preferred embodiment of the present invention, the monoazo dye is Solvent Red 195. Surprisingly, colored molding compositions containing Solvent Red 195 have significantly higher thermal stability than comparable PMMA-based molding compositions containing other red solvent dyes of the prior art, such as red perinone dyes. Therefore, the thermoplastic molding compositions of the present invention containing Solvent Red 195 are advantageously preferably substantially free of other red dyes that are soluble in the polymer matrix. Red dyes within the meaning of the present invention are those designated Solvent Red, Acid Red, or Modern Red according to the Color Index (CI). In particular, thermoplastic molding compositions of the present invention containing Solvent Red 195 typically contain less than 0.1% by weight, more preferably less than 0.01% by weight, even more preferably less than 0.001% by weight, even more preferably less than 0.0001% by weight, even more preferably less than 0.00001% by weight, and most preferably less than 0.000001% by weight of other red dyes, based on the weight of the colored molding composition.

[0027] The inventors have further found that the optical properties and thermal stability of colored molding compositions can be further improved when the colored preparation has a mass loss in the dry form of 15.0 wt. % or less, preferably 0.0 to 10.0 wt. %, more preferably 0.0 to 7.0 wt. %, even more preferably 0.0 to 5.0 wt. %, and particularly preferably 0.0 to 4.0 wt. % in isothermal thermogravimetric analysis (TGA) at 260°C for 15 minutes. When the thermoplastic polymer is substantially transparent, the colored molding composition can be obtained by the coloring process with a haze value of less than 5%, preferably less than 3%. Haze can be measured using a 3.2 mm thick sample according to standard ASTM D1003. Without wishing to be bound by theory, the inventors have surprisingly found that colored preparations with particularly low mass loss in the dry form have low solubility in the thermoplastic polymer and produce particularly low amounts of by-products that cause haze formation in the final colored molding composition.

[0028] According to the present invention, the thermoplastic polymer can be directly colored by adding the color preparation to the uncolored thermoplastic polymer in step b) or by adding a liquid composition or masterbatch containing said color preparation. When the color preparation is added to the thermoplastic polymer as a component of a liquid composition, the liquid composition typically comprises: 1.0 to 30.0 wt. %, preferably 5.0 to 25.0 wt. %, more preferably 1.0 to 20.0 wt. % of a dispersing additive; 0.5 to 50.0% by weight, preferably 5.0 to 40.0% by weight, of at least one monoazo dye as described above; 0.0 to 50.0% by weight, preferably 0.0 to 10.0% by weight, more preferably 0.0 to 5.0% by weight of auxiliary additives; liquids, e.g., demineralized water or organic solvents Including, The parts by weight of the components of the liquid composition add up to 100% by weight.

[0029] Examples of organic solvents include, but are not limited to, publicly known organic solvents such as acetone, methyl ethyl ketone, methyl-n-butyl ketone, methyl isobutyl ketone, ethyl isobutyl ketone, tetrahydrofuran, dioxane, dimethylformamide, diethylformamide, dimethylacetamide, diethylacetamide, N-methylpyrrolidone, methanol, ethanol, isopropanol, ethylene glycol, propylene glycol, 2-methoxy-2-propanol, and tetraglyme, or mixtures thereof.

[0030] The choice of dispersing additive is not particularly limited, as long as it does not adversely affect the properties of the resulting colored molding composition.The use of pH-independent dispersing additives has been shown to be particularly advantageous in terms of the thermal stability and color uniformity of the resulting colored molding composition.

[0031] For example, the dispersing additive can be a high molecular weight copolymer containing at least maleic anhydride, styrene, and an aminopolyether as monomer units. Alternatively, the dispersing additive can be a copolymer of methacrylic acid and a hydrophobic methacrylate. As used herein, the term "hydrophobic methacrylate" preferably refers to an ester of methacrylic acid with an alcohol having at least 3 and no more than 24 carbon atoms. Furthermore, the dispersing additive can be a polyether, preferably a copolymer of ethylene oxide, propylene oxide, and / or butylene oxide and styrene oxide.

[0032] Suitable dispersing additives include, for example, Dispex® Ultra 4550 (formerly EFKA® 4550), a polyacrylate commercially available from BASF SE. This polymer consists essentially of the monomers α-methylstyrene, 2-ethylhexyl acrylate, and MPEG methacrylate. Further examples of suitable dispersing additives are TEGO® Disperses 750W and 755W available from Evonik Industries AG and Disperbyk® 190 from BYK-Chemie GmbH.

[0033] Optionally, to minimize undesirable yellowing of the molding composition at high temperatures, the dispersing additive can be selected so that its mass loss in dry form is 15.0 wt. % or less, preferably 0.0 to 10.0 wt. %, more preferably 0.0 to 7.0 wt. %, even more preferably 0.0 to 5.0 wt. %, and particularly preferably 0.0 to 4.0 wt. % in isothermal thermogravimetric analysis (TGA) at 260°C for 15 minutes. Isothermal thermogravimetric analysis is performed on an automatic thermobalance, such as a TA Instruments Q5000 IR, at a heating rate of 5 K / min up to 260°C and then at 260°C for 15 minutes. Samples are not pre-treated prior to analysis, but are dried to constant mass in a drying oven prior to TGA analysis. In the case of bead polymers as dispersing aids, TGA is performed on the solid bead polymer. That is, in the case of an aqueous alkaline solution of bead polymer, the solid bead polymer used to prepare this solution is analyzed.

[0034] In addition to dispersing additives, the liquid composition may contain auxiliary additives, such as agents to prevent disintegration or bacterial degradation, bactericides, leveling agents, thickeners, and antifoaming agents.

[0035] In some embodiments, for example, when a liquid composition contains a colorant or colorant mixture insoluble in the liquid phase, particularly when its concentration is less than 10.0% by weight, viscosity adjustment may be advantageous to prevent sedimentation. This is preferably achieved by adding one or more thickeners. Preferred thickeners include, inter alia, cellulose, especially ethyl cellulose. As a further possibility, carboxylate-containing polymers available as water-soluble or alkali-soluble solid products, as colloidal solutions, or as aqueous dispersions, such as homopolymers and copolymers based on vinyl acetate and crotonic acid or partially hydrolyzed poly(meth)acrylates, can be used as thickeners. Homopolymers and copolymers of acrylic acid and / or methacrylic acid in the form of their sodium salts are particularly preferred.

[0036] The proportion of the ethylenically unsaturated free-radically polymerizable carboxylic acid is preferably 6.0% by weight or more and 80.0% by weight or less, preferably 10.0 to 80.0% by weight, in particular 20.0 to 80.0% by weight, based on the total weight of the monomers used to prepare the thickener. Acrylic acid and / or methacrylic acid and maleic acid are preferred.

[0037] The comonomers involved in forming the thickener can be ethylenically unsaturated free-radically polymerizable monomers with high or low water solubility. Beneficial effects are particularly achieved by ethylene and alkyl esters of acrylic and / or methacrylic acid having 1 to 4 carbon atoms in the alkyl group. Other usable comonomers include, for example, styrene, acrylonitrile, or vinyl acetate. Comonomers with higher hydrophilicity or water solubility, such as acrylamide and / or methacrylamide or hydroxyalkyl esters of acrylic and / or methacrylic acid, can also be used, for example, in a total proportion of about 30.0% by weight, preferably up to 10% by weight, based on the total weight of the monomers used to prepare the thickener.

[0038] The thermoplastic polymer can also be colored by adding a masterbatch containing a coloring agent to the thermoplastic polymer from step a). Masterbatch is understood to mean a blend of a coloring agent and a polymer molding compound. The concentration of the coloring agent in the masterbatch is adjusted so that the desired color impression is produced when the masterbatch is used to color the uncolored thermoplastic polymer from step a).

[0039] The masterbatch added in step b) is typically 0.01 to 50.0% by weight of a monoazo dye; 50.0 to 99.99 wt. % of a thermoplastic polymer; 0.0 to 30.0 wt. % of auxiliary additives; Contains 0.0 to 10.0 wt. % of an additional colorant.

[0040] The thermoplastic polymer in the masterbatch is typically the same as the thermoplastic polymer used in step a), and the auxiliary additives can be substantially the same as those described above. The selection of the thermoplastic polymer in step a) and the masterbatch is not particularly limited, as long as the thermoplastic polymer is suitable for coloring and thermoplastic processing, particularly injection molding and extrusion. For example, the thermoplastic polymer can be advantageously selected from the group consisting of polyalkyl(meth)acrylate, polymethylmethacrylimide, polyalkyl(meth)acrylate copolymer, polystyrene, polystyrene copolymer, acrylonitrile copolymer, polycarbonate, polyester (preferably polyethylene terephthalate), polyamide, polyvinylidene fluoride, or a mixture thereof. Preferably, the thermoplastic polymer is selected from the group consisting of polyalkyl(meth)acrylate, polymethylmethacrylimide, polyalkyl(meth)acrylate copolymer, polystyrene, polystyrene copolymer, acrylonitrile copolymer, polycarbonate, polyester (preferably polyethylene terephthalate), polyvinylidene fluoride, or a mixture thereof. More preferably, the thermoplastic polymer is selected from the group consisting of polyalkyl(meth)acrylate, polymethylmethacrylimide, polyalkyl(meth)acrylate copolymer, polycarbonate or mixtures thereof.

[0041] The thermoplastic polymer can also be pigmented by adding to the thermoplastic polymer from step a) a pigment preparation obtained from the manufacturer.

[0042] In addition to the components mentioned above, the masterbatch or liquid composition added in step b) may optionally contain one or more of the following components as further colorants: at least one further dye selected from perinone dyes, quinophthalone dyes and anthraquinone dyes, at least one inorganic pigment selected from barium sulfate, zinc oxide, iron oxide, magnesium titanate, calcium sulfate, calcium carbonate, magnesium carbonate, titanium dioxide, carbon black and dolomite; at least one phthalocyanine pigment or A mixture of any of the above

[0043] Anthraquinone dyes are dyes that have an anthraquinone moiety in their structure. Examples of suitable anthraquinone dyes include (CI) Solvent Yellow 117, 163, 167, 189; Solvent Orange 77, 86; Solvent Red 111, 143, 145, 146, 150, 151, 155, 168, 169, 172, 175, 181, 207, 222, 227, 230, 245, 247; Solvent Violet 11, 13, 14, 26, 31, 36, 37, 38, 45, 47, 48, 51, 59, 60; Solvent Includes Blue 14, 18, 35, 36, 45, 58, 59, 59:1, 63, 68, 69, 78, 79, 83, 94, 97, 98, 100, 101, 102, 104, 105, 111, 112, 122, 128, 132, 136, 139; Solvent Green 3, 28, 29, 32, 33; Acid Red 80; Acid Green 25, 27, 28, 41; Acid Violet 34; Acid Blue 25, 27, 40, 45, 78, 80, 112; Disperse Yellow 51; Disperse Violet 26, 27; Disperse Blue 1, 14, 56, 60; Direct Blue 40; Modern Red 3, 11; Modern Blue 8.

[0044] Examples of perinone dyes suitable for use in the present invention include (Color Index CI) Solvent Orange 60, 78, 90; Solvent Red 135, 162, 179; Solvent Violet 29, and the like.

[0045] Suitable quinophthalone dyes include (Color Index CI) Solvent Yellow 33, 114, 128, 129, Disperse Yellow 14, 49, 54, Disperse Yellow, and the like.

[0046] The liquid composition or masterbatch added in step b) can also contain at least one inorganic pigment.The inorganic pigment can be selected from, for example, barium sulfate, zinc oxide, iron oxide, magnesium titanate, calcium sulfate, calcium carbonate, magnesium carbonate, titanium dioxide, carbon black and dolomite.In order to avoid the formation of insoluble chemical complexes with the monoazo dye used, the inorganic pigment advantageously contains less than 100 ppm, preferably less than 50 ppm, of aluminum or its compounds and less than 300 ppm, preferably less than 200 ppm, of silicon or its compounds, expressed in ppm by weight based on the total weight of the inorganic pigment.

[0047] To impart a black or grayish color to the colored molding composition, a liquid composition or masterbatch containing carbon black can be used as needed. The average primary particle size of the carbon black pigment is preferably in the range of 5.0 to 100.0 nm, preferably 7.0 to 60.0 nm. Average particle size d 50 can be determined by methods known to those skilled in the art, for example, by photon correlation spectroscopy according to standard DIN ISO 13320 using commercially available equipment, such as the LS13320 Laser Diffraction Particle Size Analyzer manufactured by Beckman Coulter Inc. Furthermore, when measured according to the BET method, standard ISO 9277, the particle size distribution is within the range of 50 to 500 m. 2 / g, e.g., 70-200m 2It has been shown that selecting carbon black particles with a specific surface area of ​​1 / g is advantageous in terms of coloring performance. The carbon black may be treated or untreated. For example, carbon black can be treated with certain gases or organic substances, such as butyllithium. Such treatments allow the surface to be modified or functionalized, which can promote compatibility with the corresponding polymer matrix used.

[0048] Carbon black suitable within the scope of the present invention differs from so-called conductive black in that it has low or no conductivity. Compared to the carbon black used herein, conductive black has a specific morphology and superlattice structure to achieve high conductivity. In contrast, the carbon black particles used herein are very easily dispersed in thermoplastic resins, resulting in virtually no agglomerated regions of carbon black (which may result in corresponding conductivity). Suitable carbon black within the scope of the present invention is commercially available under numerous trade names and in numerous forms, such as pellets or powder. For example, suitable carbon black is available under the trade name BLACK PEARLS®, in the form of wet-processed pellets under the names ELFTEX®, REGAL®, and CSX®, and in flocculent form under the names MONARCH®, ELFTEX®, REGAL®, and MOGUL®. All of these are available from Cabot Corporation. Printex 60 and Printex 90 (Orion Engineered Carbons GmbH) are also suitable.

[0049] Preferably, the thermoplastic polymer is substantially transparent. As used in this application, the term "substantially transparent" refers to a transmittance (D) of at least 50%, preferably at least 60%, more preferably at least 70%, even more preferably at least 80%, and particularly preferably at least 90%, when measured on a sample having a thickness of 2.0 mm according to standard ISO 13468-2 (2006). 65 ) refers to a material having

[0050] Polyalkyl(meth)acrylate Polyalkyl(meth)acrylates are usually obtained by free radical polymerization of a mixture typically containing an alkyl(meth)acrylate, typically methyl methacrylate (a) and at least one additional (meth)acrylate (b). These mixtures generally contain at least 50% by weight, preferably at least 60% by weight, particularly preferably at least 80% by weight, and even more preferably at least 90% by weight of methyl methacrylate (a), based on the weight of the monomers. The amount of methyl methacrylate (a) typically used is 50.0% to 99.9% by weight, preferably 80.0% to 99.0% by weight, particularly preferably 90.0% to 99.0% by weight, based on the weight of the monomers.

[0051] These mixtures for producing polyalkyl(meth)acrylates may also contain other (meth)acrylates (b) copolymerizable with methyl methacrylate (a). As used herein, the term "(meth)acrylate" is intended to encompass methacrylates, acrylates, and mixtures thereof. (Meth)acrylates include saturated alcohols, such as methyl acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, tert-butyl (meth)acrylate, isobutyl (meth)acrylate, pentyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate; or unsaturated alcohols, such as oleyl (meth)acrylate, 2-propynyl (meth)acrylate, allyl (meth)acrylate, vinyl (meth)acrylate; and aryl (meth)acrylates, such as benzyl (meth)acrylate or phenyl (meth)acrylate, cycloalkyl (meth)acrylates, For example, it can be obtained from 3-vinylcyclohexyl (meth)acrylate, bornyl (meth)acrylate; hydroxyalkyl (meth)acrylates such as 3-hydroxypropyl (meth)acrylate, 3,4-dihydroxybutyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate; glycol di(meth)acrylates such as 1,4-butanediol (meth)acrylate; (meth)acrylates of ether alcohols such as tetrahydrofurfuryl (meth)acrylate, vinyloxyethoxyethyl (meth)acrylate; amides and nitriles of (meth)acrylic acid, and the like.

[0052] The amount of (meth)acrylic comonomer (b) generally used is 0.1% to 50.0% by weight, preferably 1.0% to 20.0% by weight, particularly preferably 1.0% to 10.0% by weight, based on the weight of the monomer. Here, the compounds can be used individually or in the form of a mixture.

[0053] The polymerization reaction is generally initiated by known free radical initiators. Among them, preferred initiators are, inter alia, azo initiators well known to those skilled in the art, such as AIBN and 1,1-azobicyclohexanecarbonitrile, and peroxy compounds, such as methyl ethyl ketone peroxide, acetylacetone peroxide, dilauryl peroxide, tert-butyl 2-ethylperhexanoate, ketone peroxide, methyl isobutyl ketone peroxide, cyclohexanone peroxide, dibenzoyl peroxide, tert-butyl peroxybenzoate, tert-butylperoxyisopropyl carbonate, 2,5-bis(2-ethylhexanoylperoxy)-2,5-dimethylhexane, tert-butyl 2-ethylperoxyhexanoate, tert-butyl 3,5,5-trimethylperoxyhexanoate, dicumyl peroxide, 1,1-bis(tert-butylperoxy)cyclohexane, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, cumyl hydroperoxide, tert-butyl hydroperoxide, bis(4-tert-butylcyclohexyl)peroxydicarbonate, or mixtures thereof.

[0054] The composition to be polymerized can contain not only the above-mentioned methyl methacrylate (a) and (meth)acrylate (b), but also other unsaturated monomers copolymerizable alone or by utilizing other monomers that facilitate copolymerization with methyl methacrylate and the aforementioned (meth)acrylate. Among these, among others, are 1-alkenes such as 1-hexene, 1-heptene; branched alkenes such as vinylcyclohexane, 3,3-dimethyl-1-propene, 3-methyl-1-diisobutylene, 4-methyl-1-pentene; acrylonitrile; vinyl esters such as vinyl acetate; styrene, substituted styrenes with alkyl substituents in the side chains such as α-methylstyrene and α-ethylstyrene, maleic acid derivatives such as maleic anhydride, methylmaleic anhydride, maleimide, methylmaleimide, and dienes such as divinylbenzene.

[0055] The amount of these comonomers (c) generally used is 0.0% to 30.0% by weight, preferably 0.0% to 15.0% by weight, particularly preferably 0.0% to 10.0% by weight, based on the weight of the monomers. Here, the compounds can be used individually or in the form of a mixture.

[0056] As the polymerizable component, (a) 50.0% by weight to 99.9% by weight of methyl methacrylate; (b) 0.1 wt% to 50.0 wt% of an acrylic acid ester of a C1 to C4 alcohol; (c) 0.0 wt % to 30.0 wt % of a monomer copolymerizable with monomers (a) and (b). Further preferred are polyalkyl(meth)acrylates obtainable by polymerization of a composition having the formula:

[0057] In a particularly preferred embodiment, the polyalkyl(meth)acrylate is a polymerizable component having, based on the weight of the polymerizable composition, (a) 80.0% by weight to 99.0% by weight of methyl methacrylate, and (b) 1.0 wt% to 20.0 wt% of an acrylic acid ester of a C1 to C4 alcohol The polymerizable composition can be obtained by polymerizing a composition comprising:

[0058] Particularly preferred is a polyalkyl(meth)acrylate composed of 80.0 to 99.5% by weight of methyl methacrylate and 0.5 to 20.0% by weight of methyl acrylate. The amounts here are based on 100% by weight of the polymerizable components. A particularly advantageous copolymer is one obtainable by copolymerizing 85.0 to 99.5% by weight of methyl methacrylate with 0.5 to 15.0% by weight of methyl acrylate. The amounts here are based on 100% by weight of the polymerizable components. For example, the polyalkyl(meth)acrylate may contain 85.0 to 99.9% by weight of methyl methacrylate and 0.1 to 15.0% by weight of methyl acrylate, preferably 95.0 to 99.9% by weight of methyl methacrylate and 0.1 to 5.0% by weight of methyl acrylate, more preferably 98.0 to 99.9% by weight of methyl methacrylate and 0.1 to 2.0% by weight of methyl acrylate. The Vicat softening point (VSP) of the polyalkyl(meth)acrylate (ISO 306:2013, method B50) is typically at least 90°C, preferably 95 to 120°C.

[0059] The weight-average molecular weight Mw of the polyalkyl(meth)acrylates is generally in the range of 50,000 g / mol to 300,000 g / mol. Particularly advantageous mechanical properties are obtained using polyalkyl(meth)acrylates whose weight-average molecular weight Mw, determined in each case by GPC against PMMA calibration standards and THF as eluent, is in the range of 50,000 g / mol to 200,000 g / mol, preferably 80,000 g / mol to 180,000 g / mol.

[0060] The corresponding copolymers are commercially available from Roehm GmbH under the trademark PLEXIGLAS®.

[0061] Poly(meth)acrylimide The poly(meth)acrylimide (PMMI) that can be used in the present invention has at least 30% by weight, preferably at least 50% by weight, and most preferably at least 60% by weight, based on the weight of the poly(meth)acrylimide, of formula (I): [ka] [In the formula, R 1 and R 2 are independently selected from hydrogen and a methyl group; R 1 and R 2 is preferably represented by a methyl group, and R 3 is hydrogen or a C1-C4 alkyl group, preferably a methyl group. Contains repeating units of

[0062] Manufacturing methods for PMMI are disclosed, for example, in EP 216505, EP 666161 or EP 776910, the entire disclosures of which are incorporated herein by reference.

[0063] The starting materials used in the production of PMMI are derived from alkyl esters of methacrylic acid and generally comprise polymers composed of more than 50.0 wt.%, preferably more than 80.0 wt.%, and particularly preferably 95.0 wt.% to 100.0 wt.% alkyl ester units of methacrylic acid having 1 to 4 carbon atoms in the alkyl group. Methyl methacrylate is preferred. Preferred polymers are composed of at least 80.0 wt.%, preferably more than 90.0 wt.%, more preferably more than 95.0 wt.%, and even more preferably more than 99.0 wt.% methyl methacrylate. The use of pure methyl methacrylate is most preferred. Comonomers that can be used include any monomer copolymerizable with methyl methacrylate, particularly alkyl esters of acrylic acid having 1 to 4 carbon atoms in the alkyl group, acrylonitrile or methacrylonitrile, acrylic or methacrylamide, styrene, or alternatively maleic anhydride. Thermoplastically processable polymers of this type having a reduced viscosity in the range of 20 ml / g to 92 ml / g, preferably 50 ml / g to 80 ml / g (measured according to ISO 8257 (2006), part 2) are preferred. They are used in the form of powders or pellets whose median particle size is about 0.03 mm to 5 mm.

[0064] Typically, PMMI for use in the present invention has a weight average molecular weight Mw of 80,000 g / mol to 200,000 g / mol, preferably 90,000 g / mol to 150,000 g / mol, as determined by GPC using PMMA as the standard. Such materials are commercially available from Röhm GmbH under the trademark PLEXIMID®. Suitable products include, but are not limited to, PLEXIMID® TT50, PLEXIMID® TT70, PLEXIMID® 8805, PLEXIMID® 8813, and PLEXIMID® 8817.

[0065] Polycarbonate Polycarbonates can also be used as thermoplastic polymers in the process of the present invention. Polycarbonates can be formally considered to be polyesters formed from carbonic acid and aliphatic or aromatic dihydroxyl compounds. They can be readily obtained by polycondensation or transesterification, for example, by reacting diglycols or bisphenols with phosgene or carbonic acid diesters.

[0066] Polycarbonates derived from bisphenols are preferred. These bisphenols include, inter alia, 2,2-bis(4-hydroxyphenyl)propane (bisphenol A), 2,2-bis(4-hydroxyphenyl)butane (bisphenol B), 1,1-bis(4-hydroxyphenyl)cyclohexane (bisphenol C), 2,2'-methylenediphenol (bisphenol F), 2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane (tetrabromobisphenol A), and 2,2-bis(3,5-dimethyl-4-hydroxyphenyl)propane (tetramethylbisphenol A), and mixtures thereof. Typically, such aromatic polycarbonates are prepared by interfacial polycondensation or transesterification. The properties of the polycarbonate can be tailored to the desired objectives by selecting the bisphenol.

[0067] scattering particles In some embodiments of the present invention, the thermoplastic polymer may further comprise organic or inorganic scattering particles dispersed in the polymer matrix. The selection of scattering particles is not particularly limited, but they are typically selected so that the refractive index of the scattering particles differs from the refractive index of the polymer matrix by at least 0.01. The refractive index can be measured at 23°C with the NaD line at 589 nm, as specified in standard ISO 489 (1999).

[0068] The scattering particles usually have a weight average particle size of 0.01 μm to 100.0 μm. The weight average particle size of the scattering particles, also known as the volume average d 50The particle size (i.e., 50% by volume of particles have a particle size less than the specified average particle size) can be measured according to the standard ISO 13320-1 (2009) for laser diffraction measurements. Typically, the size of scattering particles is determined by laser light scattering (room temperature, 23°C) using a Beckman Coulter LS13320 laser diffraction particle size analyzer, Tornado dry powder system, in each case in dry powder form. The measurement is carried out as described in the manual. The computer-aided analysis model Mie is used.

[0069] Inorganic scattering particles can include traditional inorganic opacifiers such as barium sulfate, calcium carbonate, titanium dioxide, or zinc oxide.

[0070] Organic scattering particles are typically spherical scattering beads made of cross-linked polymer materials, such as polyalkyl(meth)acrylates, silicones, polystyrene, etc. For the purposes of the present invention, the term "spherical" means that the scattering beads preferably have a spherical shape, although it is clear to those skilled in the art that scattering beads may have other shapes or may deviate from an ideal spherical shape as a result of the manufacturing method. Therefore, the term "spherical" indicates that the ratio of the largest dimension to the smallest dimension of the scattering beads is 4 or less, preferably 2 or less. Each of these dimensions is measured through the center of gravity of the scattering beads. Based on the number of scattering beads, at least 70%, in particular at least 90%, are preferably spherical.

[0071] Preferred scattering beads composed of cross-linked polystyrene are commercially available from Sekisui Plastics Co., Ltd. under the trademarks Techpolymer® SBX-4, Techpolymer® SBX-6, Techpolymer® SBX-8 and Techpolymer® SBX-12.

[0072] Other particularly preferred spherical plastic particles for use as scattering agents include crosslinked silicones. Silicone scattering agents particularly preferred for use in the present invention can be obtained from Momentive Performance Materials Inc. as TOSPEARL® 120 and TOSPEARL® 3120.

[0073] Impact modifier The mechanical properties of the colored molding composition can be further tailored to the desired target when the thermoplastic polymer contains an impact modifier. Impact modifiers for use in the present invention are well known and can have various chemical compositions and polymer structures. The impact modifiers may be crosslinked or thermoplastic. Additionally, the impact modifiers can be in particulate form, such as core-shell or core-shell-shell particles. Typically, particulate impact modifiers have an average particle size of 20 nm to 500 nm, preferably 50 nm to 450 nm, more preferably 100 nm to 400 nm, and most preferably 150 nm to 350 nm. In this context, "particulate impact modifier" generally refers to crosslinked impact modifiers having a core, core-shell, core-shell-shell, or core-shell-shell-shell structure. The average particle size of the particulate impact modifier can be determined by methods known to those skilled in the art, for example, by photon correlation spectroscopy according to standard DIN ISO 13321:1996.

[0074] In the simplest case, the particulate impact modifier is obtained by emulsion polymerization and is a crosslinked particle having an average particle size of 10 to 150 nm, preferably 20 to 100 nm, more preferably 30 to 90 nm. These generally consist of at least 20.0% by weight, preferably 20.0 to 99.0% by weight, particularly preferably 30.0 to 98.0% by weight of butyl acrylate and 0.1 to 2.0% by weight, preferably 0.5 to 1.0% by weight of a crosslinking monomer, such as a polyfunctional (meth)acrylate, for example, allyl methacrylate, and, if necessary, other monomers, such as 0.0 to 10.0% by weight, preferably 0.5 to 5.0% by weight of a C1-C4 alkyl methacrylate, for example, ethyl acrylate or butyl methacrylate, preferably methyl acrylate or other vinyl polymerizable monomers, for example, styrene.

[0075] Further preferred impact modifiers are polymer particles obtained by emulsion polymerization, which may have a core-shell or core-shell-shell structure (see, for example, EP-A-0113924, EP-A-0522351, EP-A-0465049, and EP-A-0683028). The present invention requires that these emulsion polymers have an appropriate average particle size, typically in the range of 20 nm to 500 nm, preferably 50 nm to 450 nm, more preferably 150 nm to 400 nm, and most preferably 200 nm to 350 nm.

[0076] A three-layer or three-phase structure having a core and two shells can be prepared as follows: The innermost (hard) shell can be composed of, for example, methyl methacrylate, a small amount of a comonomer, such as ethyl acrylate, and a certain amount of a crosslinker, such as allyl methacrylate. The middle (soft) shell can be composed of, for example, a copolymer containing butyl acrylate and, if necessary, styrene. Meanwhile, the outermost (hard) shell is the same as the matrix polymer, thus providing compatibility and good bonding to the matrix. The proportion of polybutyl acrylate in the core or shell of the impact modifier of a two- or three-layer core-shell structure is crucial to the impact modifier's impact-modifying effect and is preferably in the range of 20.0 to 99.0 wt. %, particularly preferably 30.0 to 98.0 wt. %, and even more preferably 40.0 to 97.0 wt. %, based on the total weight of the impact modifier.

[0077] Thermoplastic impact modifiers have a different mechanism of action than particulate impact modifiers. They are generally mixed with a matrix material. When domains are formed, for example, when using block copolymers, the preferred size of these domains, if any, can be determined, for example, by electron microscopy, and corresponds to the preferred size of the core-shell particles.

[0078] There are various classes of thermoplastic impact modifiers. One example is aliphatic thermoplastic polyurethanes (TPUs), such as the Desmopan® products available from Covestro AG. For example, the TPUs Desmopan® WDP85784A, WDP85092A, WDP89085A, and WDP89051D all have refractive indices between 1.490 and 1.500 and are particularly suitable as impact modifiers.

[0079] A further class of thermoplastic polymers for use according to the invention as impact modifiers are methacrylate-acrylate block copolymers, in particular acrylic TPEs, including PMMA-poly-n-butylacrylate-PMMA triblock copolymers, such as those sold by Kuraray under the product name Kurarity®. The poly-n-butylacrylate blocks form nanodomains in the polymer matrix having a size of 10 nm to 20 nm.

[0080] The thermoplastic polymer for use in the present invention can contain any type of additional conventional additives / auxiliaries.Among these, these are, inter alia, antistatic agents, antioxidants, mold release agents, flame retardants, lubricants, flow improvers, fillers, UV absorbers, light stabilizers and organic phosphorus compounds, such as phosphites or phosphonates, pigments, weather resistance agents and plasticizers.The selection and amount of additives can be adjusted according to the intended use.The thermal stability and weather resistance stability of the resulting colored molding composition should not be excessively impaired by these additives.

[0081] The method for producing the colored molding composition according to the present invention can be carried out by conventional incorporation methods by combining, mixing, and homogenizing the thermoplastic polymer with a liquid composition or masterbatch. This method can be carried out in the melt under the action of shear forces. The combination and mixing before melt homogenization can optionally be carried out using a powder premix, especially when the color preparation is introduced as a component of a masterbatch.

[0082] The thermoplastic polymer and the masterbatch, liquid composition, or pure colorant preparation obtained from the manufacturer can be combined, mixed, homogenized, and then extruded in conventional equipment, such as a screw-type extruder (e.g., a twin-screw extruder, ZSK), a kneader, a Brabender, or a Banbury mill. After extrusion, the extrudate can be cooled and pelletized. It is also possible to premix the individual components and then add the remaining starting materials separately and / or as a mixture.

[0083] In a further embodiment, the thermoplastic polymer can be provided in the form of a hot melt to which the liquid composition or masterbatch is added, this method being particularly advantageous for coloring the thermoplastic polymer immediately after the manufacturing process of the thermoplastic polymer.

[0084] When the thermoplastic polymer is a polyalkyl(meth)acrylate, step b) is typically carried out in an extruder at a temperature preferably in the range of 200°C to 320°C, more preferably 230°C to 300°C. This is because the molding composition has excellent thermal stability at this stage and the undesired formation of dark particles does not occur. The colored molding composition of the present invention typically has a melt volume-flow rate (MVR) of 0.5 to 10.0 g / 10 min, measured at 230°C under a load of 3.8 kg according to ISO 1133 (2011). Therefore, a colored molding composition containing a polyalkyl(meth)acrylate as the thermoplastic polymer can be advantageously used in injection molding and extrusion.

[0085] Furthermore, the present invention is directed to a colored molding composition comprising a thermoplastic polymer and a monoazo dye, the thermoplastic molding composition being obtainable by the process of the present invention as described above.

[0086] Preferably, the colored molding composition contains less than 100 ppm, preferably less than 50 ppm, of aluminum or its compounds and less than 300 ppm, preferably less than 200 ppm, of silicon or its compounds, the amount of aluminum or silicon being given herein in ppm by weight, based on the total weight of the colored molding composition.

[0087] Preferably, the colored molding composition has a melt flow rate of 0.5 to 10.0 g / 10 min when measured at 230° C. under a load of 3.8 kg.

[0088] The colored molding composition preferably has a light transmittance T in the range of 40% to 93%, in particular in the range of 70% to 92%, when measured at 23 ° C on injection-molded test specimens having a thickness of 3 mm according to DIN 5033-7 (2014). D65 Shows.

[0089] The concentration of the monoazo dye containing at least one heteroaromatic moiety in the colored molding composition depends on the desired perceived color. This concentration is generally in the range of 0.00001 to 5.0 wt.%, preferably 0.0001 to 4.0 wt.%, more preferably 0.001 to 3.0 wt.%, based on the weight of the colored molding composition. When additional dyes are present, the total dye concentration is preferably in the range of 0.00001 to 5.0 wt.%, preferably 0.0001 to 4.0 wt.%, more preferably 0.001 to 3.0 wt.%, based on the weight of the colored molding composition.

[0090] In a further aspect thereof, the present invention relates to a method for producing a molded part, comprising the step of injection molding a colored molding composition, the processing temperature of which is usually in the range of 200°C to 320°C, preferably 230°C to 300°C, and the colored molding composition is injected into a mold from which a molded part can be produced, the colored molding composition comprising a monoazo dye containing at least one heteroaromatic moiety, the colored molding composition comprising less than 100 ppm, preferably less than 50 ppm, of aluminum or compounds thereof and less than 300 ppm, preferably less than 200 ppm, of silicon or compounds thereof.

[0091] The amounts of aluminum and silicon are given above as ppm by weight, based on the total weight of the colored molding composition. For example, the aluminum and silicon contents given in ppm refer to mg of aluminum or silicon based on 1 kg of the colored molding composition.

[0092] During the injection molding process of the present invention, the temperature of the molten colored molding composition containing, for example, a polymethyl methacrylate (co)polymer is typically maintained at 210 to 270°C, and even more preferably 240 to 250°C. However, there are no intended limitations. The temperature of the injection molding nozzle is more preferably 230 to 270°C, and even more preferably 240 to 250°C, and the temperature of the injection mold is preferably 40 to 80°C, and even more preferably 50 to 60°C. The temperature of the injection molding cylinder is preferably 220 to 260°C, and even more preferably 230 to 250°C. In the method of the present invention, the molding composition is injected into the mold at a pressure in the range of 50 to 1,000 bar. In one specific embodiment herein, the pressure is applied in stages, with the pressure being 50 bar in the first stage and 400 bar in the second stage.

[0093] The injection speed can also be staged in the range of 0.01 m / s to 0.1 m / s in the first stage, 0.1 m / s to 1 m / s in the second stage, and 0.05 m / s to 0.5 m / s in a possible third stage. Herein, the metering stroke is preferably 1 to 4 times the screw diameter.

[0094] Importantly, the method of the present invention is well suited for producing complex molded parts, such as molded parts with varying thicknesses and / or perforations. Thickness differences in the corresponding injection mold, particularly perforations, i.e., the areas where the melt is injected into the mold, significantly affect the rheology of the material as it fills one or more mold cavities. For purposes of the present invention, a complex molded part is a molded part that has one or more of the following characteristics:

[0095] In one embodiment of the method of the present invention, the complex molded part has different wall thicknesses. The resulting molded part preferably has a wall thickness in the range of 1 to 30 mm, which may vary within the molded part. By way of example, the variation in wall thickness can be explained by the difference between the minimum and maximum wall thickness of the molded part, which difference is greater than 1 mm, preferably greater than 5 mm, and particularly preferably greater than 10 mm. The ratio of the maximum wall thickness to the minimum wall thickness is preferably greater than 1:20, more preferably greater than 1:10, particularly preferably greater than 1:4, and most preferably greater than 1:2.

[0096] In another embodiment of the method of the present invention, the complex molded part has at least one perforation. The wall thickness of the molded part is zero at the site of the perforation. The molded part composition surrounding the perforation may produce a uniform or variable wall thickness in the surrounding area, preferably within the ranges described above.

[0097] Another embodiment of the above-described method produces a complex molded part having at least one non-flat surface, which surface is preferably of convex or concave design.

[0098] A further aspect of the invention relates to a method for producing an extruded part, comprising extruding a colored molding composition at a temperature in the range of from 200°C to 320°C, preferably from 230°C to 300°C, wherein the colored molding composition is melted and die-cast into a final part, wherein the colored molding composition comprises a monoazo dye containing at least one heteroaromatic moiety, and wherein the colored molding composition contains less than 100 ppm, preferably less than 50 ppm, of aluminum or compounds thereof and less than 300 ppm, preferably less than 200 ppm, of silicon or compounds thereof.

[0099] The extrusion of thermoplastic polymers is widely known and is described, for example, in Kunststoffextrusionstechnik II [Plastics extrusion technology II], Hanser Verlag, 1986, p. 125 ff. In the method according to the present invention, a hot melt is extruded from the nozzle of an extruder into the gap between two calender rolls. The optimum temperature of the melt depends, for example, on the composition of the mixture and can therefore vary within a wide range. For example, when the thermoplastic polymer is a polyalkyl(meth)acrylate, the preferred temperature at the nozzle inlet is in the range of 150 to 300°C, particularly preferably in the range of 180 to 270°C, and particularly preferably in the range of 200 to 220°C. The temperature of the calender rolls is preferably 150°C or less, preferably 60 to 140°C.

[0100] Test Method TGA measurements of color preparations Isothermal thermogravimetric analysis was performed on a TA Instruments Q5000 IR automatic thermobalance at a heating rate of 5 K / min up to 260°C, followed by isothermal analysis at 260°C for 15 min. Samples were dried to constant mass in a drying oven before analysis by TGA. In the case of bead polymers as dispersing aids, TGA was performed on the solid bead polymer.

[0101] Aluminum and silicon content The aluminum and silicon content in the samples was determined using the following procedure.

[0102] The samples were digested and mineralized using a MARS5 PLUS / MARS6 microwave pressure digestion system and then analyzed using an iCAP™ 7400 ICP-OES analyzer, an atomic emission spectrometer available from ThermoFischer Scientific.

[0103] The aluminum and silicon contents are given as weight ppm (wt.-ppm) calculated based on the weight of aluminum or silicon.

[0104] Test specimen manufacturing For each example, two separate test specimens having a thickness of 3 mm were injection molded at 260°C and 290°C in an Arburg Allrounder 320C available from ARBURG GmbH & Co KG, Lossburg under the following conditions: Ejection time: 0.92 seconds Material temperature: 250℃ Cylinder temperature: 250~220℃ Mold temperature: 70℃ Switching from injection to pressure hold at 600 bar inside the mold Total cycle time: 40 seconds Injection molding with a sealed, vented cylinder

[0105] Color measurements were performed using a spectrophotometer, Color Eye 7000A, available from X-Rite Inc, Grand Rapids, United States. The color coordinates (L, a * and b * ) was measured using a spectrophotometer according to the standard DIN 5033 (2017), Parts 1 to 4, and the color difference ΔE of each sample was measured according to CIELAB 1976 (D 65, 10°) was determined according to standard DIN 6174. Specimens with a ΔE of more than 0.7 were evaluated as having poor thermal stability, specimens with a ΔE of 0.1 to 0.7 were evaluated as having good thermal stability, and specimens with a ΔE of less than 0.1 were evaluated as having excellent thermal stability.

[0106] Example The colored molding compositions of Examples 1 to 3 were produced by the following method.

[0107] The polymer granules and colorant preparations obtained from the manufacturer were used in a rotating mixer to prepare a mixture. This mixture was metered into the feed zone of a single-screw extruder 30 ESE manufactured by Herbert Stork Maschinenbau GmbH, Moerfelden, using a funnel. The extrusion was carried out at 250°C. The venting zone was attached to a vacuum pump. A granulator was connected downstream of the extruder.

[0108] In a second processing step, test specimens were injection molded from the granules thus obtained.

[0109] Example 1 (Comparative Example) A sample of Solvent Red 195 was purchased from a commercial manufacturer and used without any purification. This material contained 110 ppm aluminum, less than 15 ppm silicon, and had a mass loss in dry form of 7.4 wt %.

[0110] Solvent Red 195 is a monoazo solvent dye with a heterocyclic moiety. This material is commercially available from several manufacturers in different purities, sometimes with small amounts of additives.

[0111] Polymethyl methacrylate PLEXIGLAS® 7H, commercially available from Roehm GmbH, was used as the thermoplastic material. The resulting colored molding composition contained 0.01% by weight of Solvent Red 195.

[0112] The ΔE of the test specimen was 1.3, indicating poor thermal stability.

[0113] Example 2 (Comparative Example) A sample of Solvent Red 195 was purchased from a commercial manufacturer and used without any purification. This material contained less than 15 ppm aluminum, 370 ppm silicon, and had a mass loss in dry form of 6.2 wt %.

[0114] Polymethyl methacrylate PLEXIGLAS® 7H, commercially available from Roehm GmbH, was used as the thermoplastic material. The resulting colored molding composition contained 0.01% by weight of Solvent Red 195.

[0115] The ΔE of the test specimen was 0.74, indicating relatively poor thermal stability.

[0116] Example 3 (present invention) A high purity sample of Solvent Red 195 was used. This material contained less than 15 ppm aluminum, less than 15 ppm silicon, and had a mass loss in dry form of 3.0 wt %.

[0117] Polymethyl methacrylate PLEXIGLAS® 7H, commercially available from Roehm GmbH, was used as the thermoplastic material. The resulting colored molding composition contained 0.01% by weight of Solvent Red 195.

[0118] The ΔE of the test specimen was 0.33, indicating good thermal stability. No undesirable black dots were formed.

[0119] Example 4 (Comparative Example) The colored molding compositions of Examples 4 and 5 were produced by the following method.

[0120] The polymer granules were metered via a funnel into the feed zone of a single-screw extruder 30 ESE from Herbert Stork Maschinenbau GmbH. The liquid colorant preparation was introduced into the extruder after the second ventilation zone at a temperature ranging from 240°C to 260°C. The ventilation zone was fitted with a vacuum pump. A granulator was connected downstream of the extruder.

[0121] In a second processing step, test specimens were injection molded from the granules thus obtained.

[0122] Liquid coloring composition: 31.3% by weight Solvent Red195 * 8.1% by weight MACROLEX® Yellow G 16.7% by weight DISPEX® Ultra 4550 0.07% by weight EBOTEC® MT15 0.6wt% BYK024 43.23% water by weight * The sample was purchased from the manufacturer and used without any purification. This material contained 110 ppm aluminum, less than 15 ppm silicon, and had a mass loss in dry form of 7.4 wt %.

[0123] Polymethyl methacrylate PLEXIGLAS® 8N, commercially available from Roehm GmbH, was used as the thermoplastic material. A colored molding composition was prepared from a mixture containing 99.932 wt. % PLEXIGLAS® 8N and 0.068 wt. % of the liquid coloring composition.

[0124] Significant formation of undesirable black particles occurred during the coloring process.

[0125] Example 5 (present invention) Liquid coloring composition: 31.3% by weight Solvent Red195 * 8.1% by weight MACROLEX® Yellow G 16.7% by weight DISPEX® Ultra 4550 0.07% by weight EBOTEC® MT15 0.6wt% BYK024 43.23% water by weight * High purity sample. This material contained less than 15 ppm aluminum, less than 19 ppm silicon, and had a mass loss in dry form of 2.8 wt %.

[0126] Polymethyl methacrylate PLEXIGLAS® 8N, commercially available from Roehm GmbH, was used as the thermoplastic material. A colored molding composition was prepared from a mixture containing 99.932 wt. % PLEXIGLAS® 8N and 0.068 wt. % of the liquid coloring composition.

[0127] No undesirable black dots were formed during the coloring process and injection molding.

Claims

1. 1. A method for producing a colored molding composition, comprising: a) providing a thermoplastic polymer; b) adding a colorant preparation or a liquid composition or masterbatch comprising said colorant preparation to said thermoplastic polymer from step a); Including, The color preparation comprises a monoazo dye containing at least one heteroaromatic moiety, The color preparation contains less than 100 ppm, preferably less than 50 ppm, of aluminum or its compounds and less than 300 ppm, preferably less than 200 ppm, of silicon or its compounds; method.

2. The liquid composition added in step b) comprises, based on the weight of the liquid composition: 1.0 to 30.0 wt. % of a dispersing additive; 0.5 to 50.0% by weight of a monoazo dye, and 0.0 to 50.0 wt. % of co-additives, and liquid, preferably demineralized water Including, The weight parts of the components of the liquid composition total 100% by weight, The method of claim 1.

3. The masterbatch added in step b) comprises, based on the weight of the masterbatch: 0.01 to 50.0% by weight of a monoazo dye, 50.0 to 99.99 wt. % of a thermoplastic polymer; 0.0 to 10.0 wt. % of co-additives; 0.0 to 10.0 wt. % of an additional colorant Including, The weight parts of the components of the masterbatch total 100% by weight; The method of claim 1.

4. The monoazo dye may be 5-[(3,4-dichlorophenyl)azo]-1,2-dihydro-6-hydroxy-1,4-dimethyl-2-oxonicotinonitrile, 2,3-dihydro-2,2-dimethyl-6-((4-(phenylazo)-1-naphthyl)azo)-1H-perimidine, cyano-5-[[5-cyano-2,6-bis[(3-methoxypropyl)amino]-4-methylpyridin-3-yl]azo]-3-methyl-2-thiophenecarboxylic acid methyl ester, 5-methyl-2-phenyl-4-phenylazo-4H-pyrazole- 4. The process according to any one of claims 1 to 3, wherein the hydroxybenzoate is selected from the list consisting of 4-((2,4-dimethylphenyl)azo)-3-methyl-1-phenyl-2-pyrazolin-5-one, 4-[(2,4-dimethylphenyl)azo]-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-one, 3-[(1-oxonaphthalen-2-ylidene)methylhydrazinylidene]-1-prop-2-enylindol-2-one, 4-((o-methoxyphenyl)azo)-3-methyl-1-phenyl-2-pyrazolin-5-one and 5-methyl-2-phenyl-4-phenylazo-4H-pyrazol-3-one.

5. 5. The method of claim 1, wherein the thermoplastic polymer is selected from the group consisting of polyalkyl(meth)acrylates, polymethyl methacrylimides, polymethyl methacrylate copolymers, polystyrene, polystyrene copolymers, acrylonitrile copolymers, polycarbonates, polyesters, polyamides, polyvinylidene fluoride, or mixtures thereof.

6. 6. The method of claim 1, wherein the thermoplastic polymer comprises a polymer matrix and scattering particles dispersed in the polymer matrix, the scattering particles having a weight average particle size of 0.01 μm to 100.0 μm, and the refractive index of the scattering particles differs from the refractive index of the polymer matrix by at least 0.

01.

7. 7. The method of any one of claims 1 to 6, wherein the thermoplastic polymer comprises an impact modifier selected from particulate impact modifiers and thermoplastic impact modifiers.

8. 8. The method according to claim 1, wherein the color preparation has a mass loss in dry form in isothermal thermogravimetric analysis at 260°C for 15 minutes of not more than 15% by weight, preferably 0.0 to 10% by weight, more preferably 0.0 to 7.0% by weight, even more preferably 0.0 to 5.0% by weight, particularly preferably 0.0 to 4.0% by weight.

9. A process according to any one of claims 1 to 8, wherein step b) is carried out in an extruder, preferably at a temperature in the range of from 200°C to 320°C, more preferably from 230°C to 300°C.

10. the thermoplastic polymer is polymethyl methacrylate having a weight average molecular weight Mw of 80,000 g / mol to 180,000 g / mol, and the polymerizable component is, based on the weight of the polymerizable composition: (i) 50.0 to 99.9 wt. %, preferably 80.0 to 99.9 wt. % methyl methacrylate; (ii) 0.1 to 50.0 wt. %, preferably 0.1 to 20.0 wt. %, of an acrylic acid ester of a C1 to C4 alcohol; (iii) 0.0 to 30.0 wt. % of at least one additional monomer copolymerizable with said monomers (i) and (ii).

10. The method according to claim 1, wherein the polymer is obtainable by polymerization of a composition comprising:

11. The masterbatch or the liquid composition added in step b) is at least one further dye selected from perinone dyes, quinophthalone dyes and anthraquinone dyes, at least one inorganic pigment, at least one phthalocyanine pigment, or - A mixture of any of the above 11. The method of claim 1, further comprising:

12. A method for producing a molded part, comprising: The method comprises the step of injection molding the colored molding composition obtained by the method according to any one of claims 1 to 11 at a temperature in the range of 200 ° C to 320 ° C, preferably 230 ° C to 300 ° C, injecting the colored molding composition into a mold capable of producing the molded part; the colored molding composition comprises a monoazo dye containing at least one heteroaromatic moiety; The colored molding composition contains less than 100 ppm, preferably less than 50 ppm, of aluminum or its compounds and less than 300 ppm, preferably less than 200 ppm, of silicon or its compounds; method.

13. 1. A method for manufacturing an extruded part, comprising: The colored molding composition obtained by the method according to any one of claims 1 to 11 is extruded at a temperature in the range of 200 ° C to 320 ° C, preferably 230 ° C to 300 ° C, The colored molding composition is melted and die-cast into a final part; the colored molding composition comprises a monoazo dye containing at least one heteroaromatic moiety; The colored molding composition contains less than 100 ppm, preferably less than 50 ppm, of aluminum or its compounds and less than 300 ppm, preferably less than 200 ppm, of silicon or its compounds; method.

14. The method of claim 12 , wherein the molded part has different wall thicknesses, one or more perforations, at least one non-planar surface, or a combination of these features.

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