SILANE ANTHRAQUINONE DYES, COMPOSITE PIGMENTS OBTAINABLE THEREFROM, AND PROCESSES FOR PREPARING THE SAME

Abstract: There are described silane anthraquinone dyes, com­ posite pigments obtainable therefrom by grafting onto an inorganic substrate or support, and processes for preparing the same. The dyes have the general formula: in which: R₁ is an alkyl group containing up to 4 carbon atoms or a phenyl group; R₂ is an alkoxyl group containing up to 4 carbon atoms; n is 3, 4 or 5; q is 0 or 1; p and m are integers such that, when q is 0, p is 3 and m is 0, 1, 2 or 3, and when q is 1, p is 2 and m is 0, 1 or 2; r is 1 or 2; and X represents a divalent amino (-NH-) or amido (-NHCO-) residue, linked to the alpha or beta positions of the anthra­ quinone nucleus when r is 1, or linked to the alpha positions of the anthraquinone nucleus when r is 2, and the anthra­ quinone nucleus may be substituted by one or more R groups selected from -NH₂, -NH-alkyl C₁-C₄ -NHCO-CH₃, -NH-phenyl or -NHCO-phenyl in which the phenyl group is optionally substituted, -OH, -OCH₃, O-phenyl, -CH₃, -Cl or Br, and -NO₂. The composite pigments obtained from said dyes are utilized in paints, air and stove enamels, in the pigmentation of plastics and in printing inks.

Description: "SILANE ANTHRAQUINONE DYES, COMPOSITE PIGMENTS OBTAINABLE THEREFROM, AND PROCESSES FOR PREPARING THE SAME" This invention relates to anthraquinone dyes containing, in chemical combination, a silane group, to the corresponding composite pigments obtainable therefrom by association with an inorganic solid substrate or support, and to processes for preparing such silane anthraquinone dyes and corresponding composite pigments. Whenever used in the following description, the term "composite pigment" means a pigmentary material comprising an anthraquinone dye containing a silane group1 associated with an inorganic solid substrate or support. The association of the anthraquinone dye containing a silane group± or, briefly, silane anthraquinone dye, with the solid substrate or support, imparts pigmentary characteristics typical of the inorganic pigments to the dye. Such association is obtained by formation of chemical bonds (grafting) between the silane portion of the dye and the inorganic substrate or support. An aim of the present invention to provide silane anthraquinone dyes capable of providing composite pigments having high pigmentary characteristics. Other aims of the invention are the preparation of the aforesaid dyes and pigments by means of simple and economic methods. The present invention in one aspect provides anthraquinone dyes containing a silane group of formula: EMI2.1 in which ; R1 is an alkyl group containing up to 4 carbon atoms or a phenyl group; R2 is an alkoxyl group containing up to 4 carbon atoms; n is 3, 4 or 5; q is O or 1; p and m are integers such that, when q is O, p is 3 and m is O, 1, 2 or 3, and when q is 1, p is 2 and m is O, 1 or 2; r is 1 or 2; and X is a divalent amino (-NH-) or amido (-NHCO-) residue, linked to the alpha or beta positions of the anthraquinone nucleus when r is 1, or linked to the alpha positions of the anthraquinone nucleus when r is 2, and the anthraquinone nucleus may be substituted by one or more R groups selected from -NH2, -NH-alkyl C1-C4, -NHCO-CH3. -NH-phenyl or -NHCO-phenyl in which the phenyl group is optionally substituted, -OH, -OCH3, -O-phenyl. -CH3, -C1 or -Br, and -NO2. Such compounds according to the invention may be prepared, according to another aspect of the invention, by a process comprising reacting a silane compound of formula EMI3.1 in which n, R1 q, R2, m and p are as defined above, with the chloride of an anthraquinone carboxylic derivative of formula EMI3.2 wherein X and r are as defined above, and the anthraquinone group or nucleus may be substituted by one or more groups R as defined above, in a substantially stoichiometric molar ratio of the silane (II) to the chloride (III), in a reaction medium comprising an organic solvent, at a temperature from 200 to 1000C, for 1 to 8 hours. The reaction may be optionally conducted in the presence of a hydrochloric acid-acceptor compound such as Na2C03, NaHCO, triethylamine or pyridine. As organic solvents there may be used, for example, xylene, toluene, chloro-, dichloro- and trichloro-benzenes, nitrobenzene and dioxane. The chlorides of formula (III) are preparable according to conventional methods, for example by chlorination of the corresponding anthraquinone carboxylic derivatives with thionyl chloride SOCK2 at temperatures of from 50 to 900C in an organic solvent such as nitrobenzene. The anthraquinone carboxylic derivatives are known products and can be prepared according to conventional techniques; among those suitable for preparing the corresponding chloride there are, for example 1-(4-carboxy-phenylamino)-anthraquinone; 4-hydroxy-l -(4-carboxy-phenylamino)-anthraquinone; 4-amino-i- (4-carboxy-phenylamino) -anthraquinone; 4-phenylamino-i- (4-carboxy-phenylamino) -anthraquinone; 4-methylamino-1-(4-carboxy-phenylamino)-anthraquinone; l-(terephthaloylamino)-anthraquinone; 4-phenylamino-1-(terephthaloyamino)-anthraquinone; 1, 4-bis (-terephthaloylamino) -anthraquinone; 1,5-bis(-terephthaloylamino)-anthraquinone; 2,4-dibromo-1-(terephthaloylamino)-anthraquinone; 1-(3-carboxy-phenylamino)-anthraquinone; 1,4-bis(4-carboxy-phenylamino)-anthraquinone; 4-benzOylamino-1-(terephthaloylamino)-anthraquinone; and l-(isophthaloylamino)-anthraquinone. As silane compounds of formula (II), those derivable from amino-alkoxy-silanes, such as, for example, y-aminopropyl-triethoxysilane, 6-amino-butyl -triethoxysilane, 6-aminobutyl-phenyl-diethoxysilane, and y-aminopropyl-methyl-diethoxysilane have proved to be particularly suitable. Such amino-alkoxy-silanes are known compounds which are commercially available. However, they can be prepared1 according to conventional techniques, for example by reaction of the corresponding chloro-alkoxy-silanes with aliphatic amines. The silane anthraquinone dyes of formula (I) possess a fairly good solubility in organic solvents, have a good tinting strength, with brilliant shades in a chromatic range from greenish-yellow, to red, pure violet, blue, and are characterized by a good photostability. The silane anthraquinone dyes of formula (I) contain in their molecule silanolic groups and/or alkoxyl groups hydrolyzable to silanolic groups -Si(OH)3, are capable of both self-condensing, by reaction between the abovesaid Silanolic groups, and chemically reacting with the surface hydroxyl groups of suitable inorganic substrates or supports1 which condense with those of the dyes, with formation of stable chemical bonds (grafting) between the dye and the substrate, giving rise to a composite product having pigmentary characteristics. The abovesaid dyes are therefore preferably used in the preparation of composite pigments, according to a further aspect of the invention, comprising silane anthraquinone dyes of formula (I) grafted onto an inorganic substrate or support. The silane dyes of formula (I) in which q is O and n is 3 are particularly suitable for being utilized in preparing composite pigments. Inorganic substrates or supports particularly suitable to obtain the pigmentary nature of the silane anthraquinone dyes of formula (I) are the following: TiO2, in its forms as gel, in the semicrystalline form, in its form of rutile or anatase, also of the commercial type, in which there may be present surface coatings comprising mixtures of one or more oxides selected from SiO2, Awl 2031 TiO2; furthermore there may be used physical (mechanical) mixtures of TiO2 with SiO2 and/or Al2O3, as well as SiO2 and/or A1203. The substrates or supports are finely particulated. Owing to their superior characteristics, there are preferably employed mixed substrates of TiO2, SiO2 and/or Al 203 obtained by precipitation of SiO2 and/or Awl 2031 also as alumino-silicates, onto particles of crystalline TiO2, according to conventional methods. In relation to the desired uses, hiding degree or power or tinting strength, the above-mentioned substrates or supports may be employed also in admixture with one another. The specific surface area of such substrates or supports may vary over a wide range, from 5 to 500 m2/g, preferably from 10 to 200 m2/g. Composite pigments containing from 10 to 50% by weight of silane anthraquinone dye of formula (I) in the grafted form are particularly preferred due to their superior characteristics. According to a yet further aspect of the invention, a process for preparing the composite pigments comprising the silane anthraquinone dyes (I) grafted on the inorganic substrates or supports comprises reacting the selected substrate or support with the silane dye (I) in a reaction medium comprising water and/or an inert organic solvent, at a temperature from 200C to the reflux temperature of the reaction medium, and separating the obtained product (pigment) by filtration, followed by washing and drying. The treatment can be advantageously carried out by grinding the silane dye with the substrate or support in the reaction medium. The duration of such treatment may vary from 2 to 12 hours, depending on the reaction temperature employed. Particularly advantageous results are obtained if the composite pigment, separated by filtration, is subjected to a dry heat-treatment in an oven for 4-8 hours at 60-1100C, prior to washing, which washing is carried out in order to remove the ungrafted silane dye. To improve the condensation of the. dye coating on the substrate or support, it is possible to operate in the presence of catalysts such as LOH, CF3COOH, lead acetate, and cobalt naphthenate. Further advantages are obtainable if the abovesaid process is carried out in the presence of a compound selected from tetra-alkoxy-silanes having up to 4 carbon atoms in each alkoxy group1 such as Si(oCH3)4, or vinyltriethoxy-silane H2C= CH-Si-(oC2H5)3, or alkyl-orthotitanates, such as T(OC4H9)4' in an amount ranging approximately from 0.1:1 to 1:1 by weight in respect of the dye of formula (I), with which they form insoluble copolymers, which are particularly suitable for coating the substrate. As inert organic solvents it is possible to use, for example, aliphatic hydrocarbons (n-heptane), chlorinated derivatives thereof (tetrachloroethane), as well as alicyclic and aromatic hydrocarbons and derivatives thereof (benzene, toluene, xylenes, nitrobenzene, chlorobenzenes), alkyl or aryl ethers and ketones (N-methyl-pyrrolidone, diphenylether), oxides (dioxane), amides (dimethylformamide), nitriles (acetonitrile), and sulphoxides (dimethylsulphoxide). The preparation process of the invention is particularly suitable for obtaining intensely coloured pigments having a high tinting strength, even in the presence of inorganic substrates or supports having a low specific surface area, such as for example highly hiding TiO2. The composite pigments of the present invention may have a composition varying over a wide range, depending on the nature, granulometry and specific surface area of the substrate particles and in relation to the tinting strength desired for the pigment. Granulometric analysis of a composite pigment according to the invention shows that the organic portion is essentially distributed on the surface of the inorganic substrate particles. X-ray diffractometric analysis reveals that the composite pigment particles exhibit crystallinity which is characteristic of the substrate, while the grafted anthraquinone coating is of an amorphous nature. The anthraquinone pigments of the present invention, due to their composite nature achieved by chemical bonds between the organic silane component and the inorganic component, do not exhibit the typical drawbacks of the simple physical mixtures, wherefore they neither give rise to phenomena such as demixing of the components, differentiated sedimentation, or crystallization, nor change their crystalline form when in contact with aromatic solvents, even under hot conditions. Furthermore, pigmentary compositions based on solvents, such as those used for the printing inks, do not cause sedimentation phenomena, not even after prolonged storing. The abovesaid pigments, both in a highly hiding form and in the transparent form, exhibit excellent pigmentary characteristics, are insoluble in common organic and aqueous solvents, exhibit excellent stability to migration in polyvinyl chloride (PVC), to overpainting in stove alkyd enamels and to acid or alkaline treatments. Such pigments possess a good photostability and a good tinting strength, and are stable to heat both when obtained in the transparent form and at increasing hiding degrees. Therefore they are conveniently employed in painting products, for air and stove enamels, in the pigmentation of plastics such as PVC, polystyrene, polyethylene -terephthalate, etc., and in printing inks, according to conventional applicative techniques. The mechanical and/or thermal treatments employed in the above-mentioned conventional techniques do not substantially modify the pigmentary characteristics of the composite pigments of the present invention. The composite pigments exhibit the substantial advantage of being composed of an inorganic support or substrate, which is inexpensive and is capable of imparting excellent pigmentary characteristics, in particular the desired hiding or transparency degree and an excellent resistance to solvents1 stability to crystallization and a non-flocculating nature, on which substrate a silane anthraquinone dye, characterized by a good photostability, high tinting strength and shade purity, is grafted. In general, the composite pigments according to the invention may be suitably used for colouring paints, air and stove enamels, printing inks, and plastics materials. The invention will be further described with reference to the following illustrative examples. In the examples, all parts and percentages, unless otherwise specified, are by weight. EXAMPLE 1 A mixture consisting of 21.48 parts of 4-amino-l- (4-carboxy-phenylamino)-anthraquinone, 170 ml of nitrobenzene, 1 ml of dimethylformamide and 19.57 parts of thionyl chloride at 97% was stirred at room temperature for 30 minutes, whereafter it was heated to 950C for 3 hours. By cooling, filtering and washing with 50 ml of benzene and 500 ml of n-heptane, the chloride of the anthraquinone carboxylic derivative was isolated. A mixture consisting of 15.66 parts of the chloride so obtained, 4.2 parts of triethylamine and 150 ml of nitrobenzene was added, under stirring, at ambient temperature, with 9.3 parts of y-aminopropyl -triethoxysilane. After 2 hours, the mixture was gradually heated to 900C and was maintained at this temperature for 1.5 hours. After distillation in a solvent vapour stream, the aqueous suspension was hot filtered, washed with methanol1 and a blue powder was obtained, which, on elemental analysis, gave the following results C = 59.8%; H = 4.8%; N = 8.8%; Si = 6%. Elemental analysis and I.R. spectroscopic analysis revealed that the powder corresponded to the silane dye of formula EMI14.1 This dye may be partially present also in oligomeric form, through the formation of siloxane bonds Si O Si between the silanol functions -Si(OH) 3 present in the molecule. The dye exhibited a fairly good solubility in the usual organic solvents, as a result of which it was unsuitable for pigmentary applications. EXAMPLES 2-8 There were prepared 7 silane anthraquinone dyes of different colours by operating according to the manner of example 1, but using the anthraquinone carboxylic derivatives and the silane compounds indicated in Table 1. TABLE 1 Example Anthraquinone carboxylic derivative Silane compound Colour 2 4-hydroxy-1-(4-carboxy-phenylamino)- #-aminobutyl-triethoxy- red -anthraquinone silane 3 4-phenylamino-1-(4-carboxy-phenyl- #-aminopropyl-triethoxy- blue amino)-anthraquinone silane 4 4-methylamino-1-(4-carboxy-phenyl- #-aminopropyl-triethoxy- blue amino)-anthraquinone silane 5 1-(3-carboxy-phenylamino-anthra- #-aminobutyl-triethoxy- red quinone silane 6 4-amino-1-(3-carboxy-phanylamino)- #-aminobutyl-triethoxy- blue anthraquinone silane 7 1,4-bis-(4-carboxy-phenylamino)- #-aminopropyl-triethoxy- blue -anthraquinone silane 8 1-(4-carboxy-phenylamino)-annthra- #-aminopropyl-triethoxy- red quinone silane EXAMPLE 9 A mixture consisting of 21.5 parts of terephthalyl chloride and of 130 ml of nitrobenzene, maintained at 600C. was added with 10 parts of 1,4-diamino-anthraquinone. After 0.5 hours the mixture was heated to 1150C for 6 hours. The resulting product was filtered at 600C, repeatedly washed with acetone, with a mixture of dimethylformamide and 50% of acetone and again with acetone. A suspension consisting of 14.27 parts of the 1,4 -bis-terephthaloylamino-anthraquinone chloride so obtained, 120 ml of nitrobenzene, 3.6 parts of K2C03 and 11.5 parts of y-amino-propyl-triethoxysilane was heated to 600C for 2.5 hours and successively to 800C for a further 2 hours. From the reaction mixture, the solvent was distilled in a vapour stream and, after filtering and washing with methanol1 a powder exhibiting an intense red-violet colour was obtained which1 on elemental analysis, gave the following results C = 59.5%; H = 5.2%; N = 6.5%; Si = 6.3%. Elemental analysis and I.R. spectroscopic analysis revealed that the powder corresponded to the silane dye of formula EMI17.1 This dye may be partially present as a mixture of products of different hydrolysis degree of groups -OCH3 to groups -OH, as well as in the oligomeric form, through the formation of siloxane bonds - Si-0.-Si- between the silanol functions present in the molecule. The dye exhibited good pigmentary characteristics and a good stability to solvents, and in applications in stove alkyd enamels provided red transparent products having a good tinting strength and a good stability to overpainting. EXAMPLES 10-17 8 silane anthraquinone dyes of different colour were prepared by operating according to the manner of example 9, but using the chlorides of the anthraquinone carboxylic derivatives and the silane compounds indicated in Table 2. TABLE 2 Example Chloride of : Silane compound Colour 10 1-terephthaloylamino-anthraquinone #-aminopropyl-triethoxysilane yellow 11 1-isophthaloylamino-anthraquinone #-aminobutyl-triethoxysilane yellow 12 1,4-bis-isophthaloyamino-anthra- #-aminobutyl-triethoxysilane red quinone 13 4-hydroxy-1-terephthaloylamino- #-aminopropyl-triethoxysilane orange -anthraquinone 14 4-bromo-1-terephthaloylamino- #-aminopropyl-triethoxysilane orange -anthraquinone 15 4-benzoylamino-1-terephthaloylamino- #-aminopropyl-triethoxysilane violet -anthraquinone 16 4-phenylamino-1-terephthaloyl-amino- #-aminopropyl-triethoxysilane blue anthraquinone 17 1,5-bis-terephthaloylamino-anthra- #-aminopropyl-triethoxysilane orange quinone EXAMPLE 18 A silane anthraquinone composite pigment was prepared by using a mixed inorganic substrate of TiO2, SiO2 and Al2O3, prepared as follows : 100 parts of TiO2 were dispersed, under mechanical stirring, in 1 liter of water and the dispersion was then heated to 600C. After a 15 minute stirring, 210 ml of a sodium silicate solution (titer: 365.47 parts/liter of Si02) were added and successively, in 3 hours, 200 ml of an aluminium sulphate solution (titer: 60 parts/liter of Al 203) were additioned. The addition was stopped when the slurry pH reached a value of 6. The slurry was left under stirring for 1 hour, then the product was filtered, washed with water to remove the soluble salts, and finally dried at a temperature of 700C. The dry product was crushed and then ground in an automatic mortar. A white powder (A) was obtained, which had the following composition TiO2=43.4%; SiO=35.1%; Al2O3=7.15%; H20=14.35%, and having a specific surface area, 2 determined by a "Sorptometer", of 120 m /g, an actual specific gravity of 2.74 g/ml, an apparent specific gravity of 0.69 g/cc, a percentage porosity of 7.45 and a total porosity of 1.06 ml/g. 2 parts of the substrate (A) so obtained and 1 part of the dye obtained according to example 1 were reacted at reflux during 8 hours in a mixture consisting of 1/3 of dimethylformamide and 2/3 of xylol, the reaction mixture was cooled down to room temperature, filtered and the resulting cake was treated in an oven at llO0C overnight, whereupon it was hot washed with xylene, dimethylformamide, and methanol and finally dried. An intense blue powder was obtained which, on elemental analysis, was found to consist of 68% of inorganic ashes. This powder proved to be particularly stable to treatment, even under hot conditions, with organic solvents or with water. When used in stove alkyl enamels and in polyvinylchloride, it provided highly hiding blue products, having excellent tinting strength, stability to overpainting, to migration and to sunlight, when present both in mass and diluted with TiO2. The powdered composite pigment, subjected to X-ray diffractometric analysis, under CuK a 1.5418 radiation, was found to consist of particles having the crystallinity typical of TiO2 rutile, while Si02, A1203 and the silane anthraquinone coating proved to be amorphous. EXAMPLE 19 1 part of the dye obtained in example 1 was introduced into a reactor along with 70 parts of water and 4.2 ml of a sodium silicate solution (SiO2 content: 365.47 parts/liter). The suspension was heated to 600C and, under stirring, it was additioned, in 3 hours, with 4 ml of an aluminium sulphate solution (Al 203 content: 60 parts/liter), was maintained at 600C for 1 hour and then cooled to room temperature. After filtration, the resulting cake was washed with water to neutral pH, was dried in an oven at llO"C overnight, then repeatedly washed with hot water and finally dried. A brilliant blue powder was obtained which, on analysis, was found to consist of 67.5% of inorganic ashes. The composite pigment, on X-ray analysis, was found to consist of amorphous particles. The powder, in applications in stove enamels and in polyvinylchloride, provided fully transparent blue products, having excellent stability and photostability. EXAMPLE 20 1 part of the dye obtained according to example 1 was introduced into a reactor with 70 parts of water, 1 part of TiO2 and 2.1 ml of a sodium silicate solution (SiO2 content: 365.47 parts/liter). The suspension was heated to 600C and, under stirring, was additioned, in 3 hours, with 2 ml of an aluminium sulphate solution (A1203 content: 60 parts/liter), was maintained at 600C for 1 hour, then was cooled to room temperature. After filtering, the resulting cake was washed with water to neutral pH. was dried in an oven at 100 CC over night, then repeatedly washed with hot water and finally dried. A powder exhibiting an intense blue shade was obtained which, on elemental analysis, was found to consist of 67.5% of inorganic ashes. The product exhibited applicative characteristics as well as characteristics of stability, hiding power, tinting strength and diffractometric characteristics analogous with those of the product obtained according to example 18. EXMPLE 21 1 part of the dye obtained according to example 9 and 2 parts of the substrate obtained according to example 18 were ground during 12 hours in a grinder, in wet conditions, in a carrier consisting of dimethylformamide, then, after separation, the product was treated in an oven overnight at 1100 C, and successively washed with dimethylformamide and methanol, and finally dried. An intense-red powder was obtained which1 on elemental analysis, was found to consist of 68% of inorganic ashes. This powder proved to be particularly stable to treatment, even under hot conditions, with organic solvents or with water. In applications in stove alkyd enamels and in polyvinylchloride, it provided highly hiding, brilliant, red products with blue shades, having a good tinting strength, excellent stabilities to overpainting, to migration and to sunlight, when present both in mass and diluted with Tit2. The powdered composite pigment, subjected to X-ray diffractometric analysis, under CuK a 1.5418 radiation, was found to consist of particles having the crystallinity typical of TiO2 rutile, while SiO2, Al 203 and the silane anthraquinone coating proved to be amorphous. EXAMPLE 22 (Application in PVC) In a rotary-arm mixer there were mixed, at 700C 1.0 part of the pigment obtained according to example 18, previously ground, 100 parts of polyvinyl chloride (PVC) in powder form, 1.5 parts of calcium stearate for exerting a complexing and stabilizing action, 3.0 parts of epoxydized soybean oil, 0.5 parts of lubricant (mixture of glycerides from C16 to C36), 2.0 parts of TiO2. The resulting mixture was then treated at 1800C in a three-cylinder refiner until there was obtained complete dispersion of the pigment to obtain a highly hiding, blue sheet, having a good colour intensity, a good stability to sunlight, a good tinting strength, a good stability to heat and an excellent stability to migration. EXAMPLE 23 (Application in enamels) 5.0 parts of the pigment obtained according to example 21 were mixed by grinding with 95.0 parts of a fluid carrier having the following composition 22% of alkyd resin, 19% of melamine resin, 59% of xylene. Homogenizing was accomplished in a ball mill by grinding the mixture in the presence of porcelain balls of 10 mm diameter, for 24 hours. The enamel so obtained was applied onto a surface to be painted, and was allowed to dry overnight and then it was placed into an oven and left there during 30 minutes at 1200-1250C. A red painting exhibiting excellent hiding power, stability to sunlight and to overpainting as well as a good tinting strength was obtained. With a view to obtaining a paint having a lighter shade and a higher hiding power, 1 part of the enamel prepared as described hereinabove was further diluted with 9 parts of a white synthetic stove enamel (10% of TiO2) having the following composition 30% of alkyd resin, 27% of melamine resin, 33% of xylene, 10% of TiO 2 Homogenizing was carried out in a ball mill by grinding the mixture in the presence of porcelain balls of 10mum diameter, during 24 hours. The cut enamel so obtained was applied onto the surface to be painted, was allowed to dry overnight, then was placed into an oven and left there at 1200-1250C for 30 minutes. A pale red paint was obtained, having excellent general stabilities and a high hiding power.

Claims: CLAIMS 1. An anthraquinone dye containing a silane group, characterized by having the formula EMI27.1 in which : R1 is an alkyl group containing up to 4 carbon atoms or a phenyl group; R2 is an alkoxyl group containing up to 4 carbon atoms; n is 3, 4 or 5: q is 0 or 1; p and m are integers such that, when q is O. p is 3 and m is 0, 1, 2 or 3, and when q is 1, p is 2 and m is 0, 1 or 2; r is 1 or 2; and X represents a divalent amino (-NH-) or amido (-NHCO-) residue, linked to the alpha or beta positions of the anthraquinone nucleus when r is 1, or linked to the alpha positions of the anthraquinone nucleus when r is 2, and the anthraquinone nucleus may be substituted by one or more R groups selected from -NH2, -NH-alkyl C1-C41 -NHCO-CH3 -NH-phenyl or -NHCO-phenyl in which the phenyl group is optionally substituted, -OH, -OCH3, -O-phenyl, -CH3, -C1 or -Br, and -NO2. 2. A silane anthraquinone dye as claimed in claim 1, characterized in that q is 0 and m is 3. 3. A process for preparing an anthraquinone dye according to claim 1, characterized by comprising reacting a silane compound of formula EMI28.1 in which n, R1, q, R2, m and p are as defined in claim 1, with a chloride of an anthraquinone carboxylic derivative of formula EMI28.2 in which X and r as defined in claim 1 and the anthraquinone nucleus may be substituted by one or more groups R as defined in claim 1, in a substantially stoichiometric molar ratio of the silane (II) to the chloride (III), in a reaction medium comprising an organic solvent, at a temperature from 200 to 1000C, for 1 to 8 hours. 4. A process as claimed in claim 3, characterized in that the reaction is carried out in the presence of a hydrochloric acid-acceptor compound. 5. A process as claimed in claim 4, characterized in that the hydrochloric acid-acceptor compound is selected from Na2CO31 NaHCO31 triethylamine and pyridine. 6. A process as claimed in any of claims 3 to 5, characterized in that the amino-alkoxysilane of formula (II) is selected from y-aminopropyl-triethoxysilane. 6-aminobutyl-phenyl-diethoxysilane, y-aminopropylmethyl-diethoxysilane, and 6-aminobutyl-tri -ethoxysilane. 7. A process as claimed in any of claims 3 to 6, characterized in that the organic solvent is selected from xylene, toluene, chloro-, dichloro- and trichloro-benzenes, nitrobenzene, and dioxane. 8. A composite pigment, characterized by comprising a silane anthraquinone dye as claimed in claim 1 or 2, grafted onto a solid inorganic substrate or support. 9. A composite pigment as claimed in claim 8, characterized in that the inorganic substrate or support is selected from TiO2 gel, semicrystalline TiO2, rutile TiO2 and anatase Tit2, mixtures of TiO2 with SiO2 and/or Al2O3; sio2 and/or Al2O3; and mixtures thereof; the said substrate or support being optionally finely particled and having a specific 2 surface area of from 5 to 500 m /g. 10. A composite pigment as claimed in claim 8 or 9, characterized by containing from 10 to 50% by weight of silane anthraquinone dye in grafted form. 11. A process for preparing a composite pigment according to claim 8, characterized by comprising reacting the inorganic substrate or support with a silane anthraquinone dye of formula (I) in a reaction medium comprising water and/or an inert organic solvent, at a temperature from 200C to the reflux temperature of the reaction medium, and separating the obtained product by filtration, followed by washing and drying. 12. A process as claimed in claim 11, characterized in that the reaction is carried out by grinding the silane dye with the substrate or support in the presence of the reaction medium, for 2-12 hours. 13. A process as claimed in claim 11 or 12, characterized in that the composite pigment, separated by filtration, is subjected to a dry heat-treatment in an oven at 60-1100C for 4-8 hours prior to washing. 14. A process as claimed in any of claims 11 to 13, characterized in that the reaction is conducted in the presence of a catalyst selected from LiOH, CF3COOH, lead acetate and cobalt naphthenate. 15. A process as claimed in any of claims 11 to 14, characterized in that the reaction is conducted in the presence of a compound selected from tetra-alkoxysilanes containing up to 4 carbon atoms in each alkoxy group, vinyltriethoxysilane and alkylorthotitanates, in a weight ratio with respect to the dye (I) of from 0.1:1 to 1:1. 16. A paint, air enamel, stove enamel, printing ink or plastics material, when coloured with a composite pigment as claimed in any of claims 8 to 10.

Inventors: CARLINI, FILIPPO MARIA, MARANZANA, GIORGIO, MARRACCINI, ANTONIO, PASQUALE, ANTONIO
Applicants: MONTEDISON S.P.A.
Application year: 1984
Main classification: C09B69
IPC codes: C09B67, C09C1, C09B69, C09B1