EFFECT PIGMENTS

Abstract

The invention relates to glaze- and enamel-stable effect pigments having a top layer comprising at least one tin/antimony mixed oxide, which have improved stability, in particular at temperatures above 1000 C., in glazes, enamels, ceramic or glass-like materials.

Claims

1. Effect pigment based on a flake-form substrate, characterised in that the pigment has on the surface a top layer comprising one or more tin/antimony mixed oxides.

2. Effect pigment according to claim 1, characterised in that the effect pigment has on the surface a top layer comprising Sn.sub.xSb.sub.1-xO.sub.2 and x is a number between 0 and 1.

3. Effect pigment according to claim 1, characterised in that the top layer is in the cassiterite structure.

4. Effect pigment according to claim 1, characterised in that the top layer is 1-100% by weight based on the entire pigment.

5. Effect pigment according to claim 1, characterised in that the top layer has a thickness of 1-500 nm.

6. Effect pigment according to claim 1, characterised in that the effect pigment is selected from the group of the pearlescent pigments, interference pigments, multilayered pigments or holographic pigments.

7. Effect pigment according to claim 1, characterised in that the effect pigment is based on natural or synthetic mica flakes, muscovite flakes, sericite flakes, fluorophlogopite flakes, Zn phlogopite flakes, SiO.sub.2 flakes, glass flakes, TiO.sub.2 flakes, flake-form BN, flake-form SiC, Al.sub.2O.sub.3 flakes or titanate flakes.

8. Effect pigment according to claim 1, characterised in that the effect pigment comprises at least one TiO.sub.2 layer and/or at least one titanium oxynitride layer on the flake-form substrate.

9. Effect pigment according to claim 1, characterised in that the effect pigment has the following structure, plus the top layer: substrate flake+TiO.sub.2 substrate flake+titanium oxynitride substrate flake+SiO.sub.2+TiO.sub.2 substrate flake+SnO.sub.2+TiO.sub.2 substrate flake+Cr.sub.2O.sub.3+TiO.sub.2 substrate flake+Ce.sub.2O.sub.3+TiO.sub.2 substrate flake+ZrO.sub.2+TiO.sub.2 substrate flake+TiO.sub.2+Cr.sub.2O.sub.3 substrate flake+TiO.sub.2+SiO.sub.2+TiO.sub.2 substrate flake+TiO.sub.2+SiO.sub.2 substrate flake+TiO.sub.2+SnO.sub.2+TiO.sub.2 substrate flake+TiO.sub.2+Fe.sub.2O.sub.3 substrate flake+Fe.sub.2O.sub.3+TiO.sub.2 substrate flake+TiO.sub.2+Al.sub.2O.sub.3+TiO.sub.2 substrate flake+TiO.sub.2+ZrO.sub.2+TiO.sub.2

10. Effect pigment according to claim 1, characterised in that the effect pigment is selected from the following group of effect pigments, plus the top layer: natural phyllosilicate flakes+TiO.sub.2 natural phyllosilicate flakes+titanium oxynitrides natural phyllosilicate flakes+TiO.sub.2+SiO.sub.2+TiO.sub.2 natural phyllosilicate flakes+TiO.sub.2+SnO.sub.2+TiO.sub.2 synthetic phyllosilicate flakes+TiO.sub.2 synthetic phyllosilicate flakes+titanium oxynitrides synthetic phyllosilicate flakes+TiO.sub.2+SiO.sub.2+TiO.sub.2 synthetic phyllosilicate flakes+TiO.sub.2+SnO.sub.2+TiO.sub.2 Al.sub.2O.sub.3 flakes+TiO.sub.2 Al.sub.2O.sub.3 flakes+titanium oxynitrides Al.sub.2O.sub.3 flakes+TiO.sub.2+SiO.sub.2+TiO.sub.2 SiO.sub.2 flakes+TiO.sub.2 SiO.sub.2 flakes+titanium oxynitrides SiO.sub.2 flakes+TiO.sub.2+SiO.sub.2+TiO.sub.2 glass flakes+TiO.sub.2 glass flakes+titanium oxynitrides SiC flakes+TiO.sub.2 SiC flakes+titanium oxynitrides BN flakes+TiO.sub.2 BN flakes+titanium oxynitrides Fe.sub.2O.sub.3 flakes+TiO.sub.2 Fe.sub.2O.sub.3 flakes+titanium oxynitrides TiO.sub.2 flakes+TiO.sub.2 TiO.sub.2 flakes+ZrO.sub.2+TiO.sub.2 TiO.sub.2 flakes+SiO.sub.2+TiO.sub.2 titanate flakes+TiO.sub.2 titanate flakes+ZrO.sub.2+TiO.sub.2 titanate flakes+SiO.sub.2+TiO.sub.2

11. Process for the preparation of the effect pigments according to claim 1, comprising applying the tin/antimony mixed oxide layer to the effect pigment by wet-chemical methods or by chemical or physical gas-phase coating.

12. A composition for paints, coatings, printing inks, plastics, ceramic materials, glasses, for the laser marking of plastics and papers, in cosmetic formulations, for the preparation of pigment preparations or for dry preparations, comprising an effect pigment according to claim 1.

13. A composition for ceramic bodies, ceramic colours, glazes, engobes, enamels or glass, comprising an effect pigment according to claim 1.

14. A pigment formulation comprising the effect pigment according to claim 1.

Description

EXAMPLES

Example 1

[0076] 100 g of Iriodin 103 (TiO.sub.2 mica pigment from Merck) are stirred in 2 l of demineralised water and heated to 70 C. This is followed by the metered addition of 30 g of a 32% antimony(III) chloride solution and 160 g of a 50% tin chloride solution, during which the pH of 3.0 is kept constant by simultaneous dropwise addition of a 32% sodium hydroxide solution. When the addition is complete, the mixture is stirred for a further 30 min. The product is filtered off, washed, dried at 110 C. for 10 h and subsequently calcined at 850 C. for 30 min. This is followed by sieving. This gives an effect pigment with a white mass tone and high gloss which has the following particle size distribution:

D.SUB.10.=10 m

D.SUB.90.=60 m.

[0077] The effect pigment from Example 1, coated with Sn.sub.xSb.sub.1-xO.sub.2, where x=0.9, is stable at temperatures >1000 C.

Example 2

[0078] 100 g of Xirallic Crystal Silver (Al.sub.2O.sub.3 flakes coated with TiO.sub.2, effect pigment from Merck) are suspended in 2 l of demineralised water and the suspension is heated to 85 C. This is followed by the metered addition of 30 g of a 32% antimony(III) chloride solution and 160 g of a 50% tin chloride solution, during which the pH of 3.0 is kept constant by simultaneous dropwise addition of a 32% sodium hydroxide solution. When the addition is complete, the mixture is stirred for a further 30 min. The product is filtered off, washed, dried at 110 C. for 12 h and subsequently calcined at 850 C. for 45 min. This is followed by sieving.

[0079] This gives an effect pigment with a white mass tone, very high gloss and a very intense sparkle effect which has the following particle size distribution:

D.SUB.10.=5 m

D.SUB.90.=30 m.

[0080] The effect pigment from Example 2, coated with Sn.sub.xSb.sub.1-xO.sub.2, where x=0.9, is stable at temperatures >1100 C.

Example 3

[0081] 100 g of Xirallic Miraval Cosmic Silver (glass flakes coated with TiO.sub.2, effect pigment from Merck) are suspended in 2 l of demineralised water and the suspension is heated to 85 C. This is followed by the metered addition of 30 g of a 32% antimony(III) chloride solution and 160 g of a 50% tin chloride solution, during which the pH of 3.0 is kept constant by simultaneous dropwise addition of a 32% sodium hydroxide solution. When the addition is complete, the mixture is stirred for a further 30 min. The product is filtered off, washed, dried at 110 C. for 12 h and subsequently calcined at 850 C. for 45 min. This is followed by sieving. This gives an effect pigment with a white mass tone, very high gloss and a very intense sparkle effect which has the following particle size distribution:

D.SUB.10.=20 m

D.SUB.90.=200 m.

[0082] The effect pigment from Example 3, coated with Sn.sub.xSb.sub.1-xO.sub.2, where x=0.9, is stable at temperatures >1000 C.

Example 4

[0083] 100 g of mica flakes (N fraction, particle size: 10-60 m) are stirred in 2 l of demineralised water and heated to 70 C. This is followed by the metered addition of 90 g of tin(IV) chloride solution, during which the pH of 2.3 is kept constant by simultaneous dropwise addition of a 32% sodium hydroxide solution. 200 g of titanium(IV) chloride solution are then metered in, during which the pH of 1.9 is kept constant by simultaneous dropwise addition of a 32% sodium hydroxide solution. This is followed by the metered addition of 30 g of a 32% antimony(III) chloride solution and 160 g of a 50% tin chloride solution, during which the pH of 3.0 is kept constant by simultaneous dropwise addition of a 32% sodium hydroxide solution. When the addition is complete, the mixture is stirred for a further 30 min. The product is filtered off, washed, dried at 110 C. for 10 h and subsequently calcined at 850 C. for 30 min. This is followed by sieving. This gives an effect pigment with a white mass tone and high gloss which has the following particle size distribution:

D.SUB.10.=10 m

D.SUB.90.=60 m.

[0084] The effect pigment from Example 4, coated with Sn.sub.xSb.sub.1-xO.sub.2, where x=0.9, is stable at temperatures >1000 C.

Example 5

[0085] 100 g of mica flakes (F fraction, particle size: 5-25 m) are stirred in 2 l of demineralised water and heated to 70 C. This is followed by the metered addition of 90 g tin(IV) chloride solution, during which the pH of 2.3 is kept constant by simultaneous dropwise addition of a 32% sodium hydroxide solution. 200 g of titanium(IV) chloride solution are then metered in, during which the pH of 1.9 is kept constant by simultaneous dropwise addition of a 32% sodium hydroxide solution. This is followed by the metered addition of 30 g of a 32% antimony(III) chloride solution and 160 g of a 50% tin chloride solution, during which the pH of 3.0 is kept constant by simultaneous drop-wise addition of a 32% sodium hydroxide solution. When the addition is complete, the mixture is stirred for a further 30 min. The product is filtered off, washed, dried at 110 C. for 10 h and subsequently calcined at 850 C. for 30 min. This is followed by sieving.

[0086] This gives an effect pigment having a white mass tone and moderate gloss which has the following particle size distribution:

D.SUB.10.=5 m

D.SUB.90.=25 m.

[0087] The effect pigment from Example 5, coated with Sn.sub.xSb.sub.1-xO.sub.2, where x=0.9, is stable at temperatures >1000 C.

Example 6

[0088] 100 g of Iriodin 100 (mica flakes coated with TiO.sub.2, effect pigment from Merck) are stirred in 2 l of demineralised water and heated to 70 C. This is followed by the metered addition of 30 g of a 32% antimony(III) chloride solution and 160 g of a 50% tin chloride solution, during which the pH of 3.0 is kept constant by simultaneous dropwise addition of a 32% sodium hydroxide solution. When the addition is complete, the mixture is stirred for a further 30 min. The product is filtered off, washed, dried at 110 C. for 10 h and subsequently calcined at 1000 C. for 30 min. This is followed by sieving.

[0089] This gives an effect pigment having a white mass tone and high gloss which has the following particle size distribution:

D.SUB.10.=10 m

D.SUB.90.=60 m.

[0090] The effect pigment from Example 6, coated with Sn.sub.xSb.sub.1-xO.sub.2, where x=0.9, is stable at temperatures >1000 C.

Example 7

[0091] 100 g of Iriodin 123 (mica flakes coated with TiO.sub.2, effect pigment from Merck) are stirred in 2 l of demineralised water and heated to 70 C. This is followed by the metered addition of 30 g of a 32% antimony(III) chloride solution and 160 g of a 50% tin chloride solution, during which the pH of 3.0 is kept constant by simultaneous dropwise addition of a 32% sodium hydroxide solution. When the addition is complete, the mixture is stirred for a further 30 min. The product is filtered off, washed, dried at 110 C. for 10 h and subsequently calcined at 850 C. for 30 min. This is followed by sieving.

[0092] This gives an effect pigment having a white mass tone and moderate gloss and sparkle effect which has the following particle size distribution:

D.SUB.10.=5 m

D.SUB.90.=25 m.

[0093] The effect pigment from Example 7, coated with Sn.sub.xSb.sub.1-xO.sub.2, where x=0.9, is stable at temperatures >1000 C.

Example 8

[0094] 100 g of Iriodin 6163 (synthetic mica flakes coated with TiO.sub.2, effect pigment from Merck) are suspended in 2 l of demineralised water and the suspension is heated to 85 C. This is followed by the metered addition of 30 g of a 32% antimony(III) chloride solution and 160 g of a 50% tin chloride solution, during which the pH of 3.0 is kept constant by simultaneous dropwise addition of a 32% sodium hydroxide solution. When the addition is complete, the mixture is stirred for a further 30 min. The product is filtered off, washed, dried at 110 C. for 12 h and subsequently calcined at 850 C. for 45 min. This is followed by sieving.

[0095] This gives an effect pigment having a white mass tone, high gloss and a high sparkle effect which has the following particle size distribution:

D.SUB.10.=20 m

D.SUB.90.=180 m.

[0096] The effect pigment from Example 8, coated with Sn.sub.xSb.sub.1-xO.sub.2, where x=0.9, is stable at temperatures >1000 C.

Example 9

[0097] 100 g of Colorstream Viola Fantasy (SiO.sub.2 flakes coated with TiO.sub.2, effect pigment from Merck) are suspended in 2 l of demineralised water and the suspension is heated to 85 C. This is followed by the metered addition of 30 g of a 32% antimony(III) chloride solution and 160 g of a 50% tin chloride solution, during which the pH of 3.0 is kept constant by simultaneous dropwise addition of a 32% sodium hydroxide solution. When the addition is complete, the mixture is stirred for a further 30 min. The product is filtered off, washed, dried at 110 C. for 12 h and subsequently calcined at 850 C. for 45 min. This is followed by sieving.

[0098] This gives an effect pigment having a white mass tone, very high gloss and a colour flop which has the following particle size distribution:

D.SUB.10.=5 m

D.SUB.90.=50 m.

[0099] The effect pigment from Example 9, coated with Sn.sub.xSb.sub.1-xO.sub.2, where x=0.9, is stable at temperatures >1000 C.

Example 10

[0100] 100 g of Iriodin 183 (mica flakes coated with TiO.sub.2, effect pigment from Merck) are stirred in 2 l of demineralised water and heated to 70 C. This is followed by the metered addition of 30 g of a 32% antimony(III) chloride solution and 160 g of a 50% tin chloride solution, during which the pH of 3.0 is kept constant by simultaneous dropwise addition of a 32% sodium hydroxide solution. When the addition is complete, the mixture is stirred for a further 30 min. The product is filtered off, washed, dried at 110 C. for 10 h and subsequently calcined at 1000 C. for 30 min. This is followed by sieving.

[0101] This gives an effect pigment having a white mass tone, high gloss and an intense sparkle effect which has the following particle size distribution:

D.SUB.10.=45 m

D.SUB.90.=500 m.

[0102] The effect pigment from Example 10, coated with Sn.sub.xSb.sub.1-xO.sub.2, where x=0.9, is stable at temperatures >1000 C.

Example 11

[0103] 100 g of Iriodin 103 (TiO.sub.2 mica pigment from Merck) are stirred in 2 l of demineralised water and heated to 70 C. This is followed by the metered addition of 60 g of a 32% antimony(III) chloride solution and 160 g of a 50% tin chloride solution, during which the pH of 3.0 is kept constant by simultaneous dropwise addition of a 32% sodium hydroxide solution. When the addition is complete, the mixture is stirred for a further 30 min. The product is filtered off, washed, dried at 110 C. for 10 h and subsequently calcined at 850 C. for 30 min. This is followed by sieving.

[0104] This gives an effect pigment having a white mass tone and high gloss which has the following particle size distribution:

D.SUB.10.=10 m

D.SUB.90.=60 m.

[0105] The effect pigment from Example 11, coated with Sn.sub.xSb.sub.1-xO.sub.2, where x=0.8, is stable at temperatures >1000 C.

Example 12

[0106] 100 g of Iriodin 103 (TiO.sub.2 mica pigment from Merck) are stirred in 2 l of demineralised water and heated to 70 C. This is followed by the metered addition of 30 g of a 32% antimony(III) chloride solution and 50 g of a 50% tin chloride solution, during which the pH of 3.0 is kept constant by simultaneous dropwise addition of a 32% sodium hydroxide solution. When the addition is complete, the mixture is stirred for a further 30 min. The product is filtered off, washed, dried at 110 C. for 10 h and subsequently calcined at 850 C. for 30 min. This is followed by sieving.

[0107] This gives an effect pigment having a white mass tone and high gloss which has the following particle size distribution:

D.SUB.10.=10 m

D.SUB.90.=60 m.

[0108] The effect pigment from Example 12, coated with Sn.sub.xSb.sub.1-xO.sub.2, where x=0.7, is stable at temperatures >1000 C.

[0109] The improved stability of the pigments prepared in Examples 1-12 is in each case shown by the application-specific test compared with the unstabilised pigment. To this end, the unstabilised pigment (for example Iriodin 103 in Example 1) and the pigment stabilised in each case is used in the same way and the two workpieces are assessed visually with respect to their colour and their pearlescence effect. The stabilised pigments in each case show less discolouration and a better pearlescence effect compared with the corresponding standard commercial or unstabilised effect pigment.

[0110] Use for screen printing on porcelain workpieces, which is divided into 3 steps, may be given here as representative.

1) Preparation of the Printing Paste

[0111] For the production of fine colour screens and relief-like prints on ceramic substrates by means of ceramic inks, use is made of screen-printing oils which prevent flow of the ink pastes of the printing and give rise to prints with sharp contours. To this end, use is made of additions to the known binders which consist of finely divided natural or synthetic waxes and/or finely divided inorganic silicate or oxidic substances which are capable of incorporation into the silicate framework of the fluxing agent. The pearlescent pigment with the corresponding amount of frit and the printing medium (screen printing oil 221-ME and Screenprint Bulk 803035 MRboth standard commercial products from Ferrowere employed in the examples) are weighed out and homogenised for a series of experiments.

[0112] The effect pigment from Examples 1 to 10 is weighed out and homogenised with the corresponding amount of frit of the following composition

TABLE-US-00002 Frit CaO Na.sub.2O K.sub.2O BaO Al.sub.2O.sub.3 SiO.sub.2 B.sub.2O.sub.3 % by wt. 9.7 5.2 1.1 1.3 10.1 69.6 3.0

[0113] The following steps are independent of the composition of the printing paste.

2) Printing of Tiles

[0114] The printing paste obtained can be applied to tiles by standard printing processes, slip processes, spray application or transfer printing. In all cases, the printed tile is dried at temperatures of 60-110 C. in a drying cabinet or fume hood in order to evaporate off the solvent present in the printing oil. In the examples according to the invention, the printing paste is applied to the tiles by means of knife coater and printing screen.

3) Firing of the Printed Tiles

[0115] The printed and dried tile is then fired in the firing oven by means of a temperature profile.

180 min: heating to 1100 C.,
3 min: holding at 1100 C.,
120 min: rapid cooling to 600 C.,
300 min: slow cooling to room temperature.