Coated pigments, method for the production and the use thereof, coating agent and article

Abstract

The present invention relates to a particularly effective protective coating for metallic objects, the coating method, and the special applications thereof. The particularly high protective effect is achieved by the adaptation of the inorganic fraction and the organic polymer fraction of the coating to the specific surface of the object. Further adjustments of the coating can be used for further optimization, for example of the protection properties or other product properties.

Claims

1. A pigment comprising a metallic substrate and at least one inorganic/organic hybrid layer, wherein the inorganic/organic hybrid layer comprises at least one metal oxide, at least one network former, and at least one organic polymer, wherein the at least one metal oxide does not constitute an oxidation product of the metallic substrate, and the term metal oxide comprises oxides, hydroxides, and oxide hydrates of the metals and semimetals, wherein the network former is joined at least partially covalently to the metal oxide and to the organic polymer, wherein the ratio of the amount of metal oxide of the inorganic/organic hybrid layer to the specific surface area of the uncoated metal pigment is in a range from 16.1 mg/m.sup.2 to 25 mg/m.sup.2, and the ratio of the amount of organic polymer of the inorganic/organic hybrid layer to the specific surface area of the uncoated metal pigment is in a range from 3.9 mg/m.sup.2 to 10.1 mg/m.sup.2.

2. The pigment according to claim 1, wherein the metallic substrate is platelet-shaped.

3. The pigment according to claim 1, wherein the organic polymer is not polyethylene.

4. The pigment according to claim 1, wherein the ratio of the amount of metal oxide of the coating to the specific surface area of the uncoated metal pigment is in a range from 17.2 mg/m.sup.2 to 23 mg/m.sup.2.

5. The pigment according to claim 1, wherein the ratio of the amount of organic polymer of the inorganic/organic hybrid layer to the specific surface area of the uncoated metal pigment is in a range from 4.6 mg/m.sup.2 to 9.7 mg/m.sup.2.

6. The pigment according to claim 1, wherein the thickness of the inorganic/organic hybrid layer is at least 40% of the total thickness of the coating.

7. The pigment according to claim 1, wherein the amount of the inorganic/organic hybrid layer is at least 5 wt %, based on the total weight of the pigment.

8. The pigment according to claim 1, wherein the at least one metal oxide of the inorganic/organic hybrid layer is selected from the group consisting of silicon oxide, aluminum oxide, boron oxide, zirconium oxide, cerium oxide, iron oxide, titanium oxide, chromium oxide, tin oxide, molybdenum oxide, vanadium oxide, zinc oxide, magnesium oxide, and mixtures thereof, the term metal oxide also comprises oxide hydrates and hydroxides.

9. The pigment according to claim 1, wherein at least one heteropolysiloxane has been applied to at least one inorganic/organic hybrid layer, wherein the at least one heteropolysiloxane is prepared from at least one aminosilane and at least one silane selected from the group consisting of alkylsilanes, vinylsilanes, and arylsilanes.

10. The pigment according to claim 1, wherein at least 95 wt % of the metal of the metallic substrate are selected from the group consisting of aluminum, iron, copper, and brass, based on the weight of the metal of the metallic substrate without oxygen.

11. The pigment according to claim 1, wherein at least one network former is selected from the compounds of formula (NI),
R.sup.an1.sub.xn1R.sup.bn1.sub.yn1SiX.sub.(4-xn1-yn1)(NI) wherein the Xs independently of one another are selected from hydrolyzable groups after whose hydrolysis a covalent bond of organic network former to the inorganic network can be formed, the R.sup.an1s independently of one another are selected from reactive organic groups which can be joined covalently to the organic polymer, the R.sup.bn1s independently of one another are selected from organic groups which can be joined covalently to the organic polymer, xn1 is an integer from 1 to 3, and yn1 is an integer from 0 to (3xn1).

12. The pigment according to claim 1, wherein the inorganic/organic hybrid layer comprises at least one network former of formula (NI), wherein the Xs independently of one another are selected from the group consisting of C1-C4 alkoxy groups without heteroatoms in the carbon chain, the R.sup.an1s independently of one another are selected from the group consisting of substituted C1-C10 alkyl groups, the substituents are selected from the group consisting of acrylate groups, methacrylate groups and mixtures thereof, the R.sup.bn1s independently of one another are selected from the group consisting of C1-C24 alkyl groups, C6-C18 aryl groups, C7-C24 alkylaryl groups, C7-C24 arylalkyl groups, C5-C16 cycloalkyl groups, and C6-C20 alkylcycloalkyl groups, the aforesaid groups are unsubstituted and contain no heteroatoms in the carbon chains and carbon ring systems, xn1 is an integer from 1 to 3, and yn1 is an integer 0 or 1.

13. The pigment according to claim 1, wherein the organic polymer is selected from the group consisting of polyacrylates, polymethacrylates, polyethers, polyesters, polyamines, polyamides, polyols, polyurethanes, and polyolefins, the polyolefins including no polyethylene.

14. A method for producing metal pigments comprising metallic substrate and coating, comprising the following steps: i) reacting at least one metal oxide reactant, at least one reactant of an organic polymer, and at least one network former in a liquid phase to form a coating composition, ii) applying the coating composition to metallic substrates to form an inorganic/organic hybrid layer, wherein the inorganic/organic hybrid layer comprises at least one inorganic network comprising at least one metal oxide and at least one organic polymer, and the inorganic network and the organic polymer are joined covalently to one another, the at least one metal oxide does not constitute an oxidation product of the metallic substrate, and the term metal oxide comprises oxides, hydroxides, and oxide hydrates of the metals and semimetals, the network former is joined at least partially to the metal oxide and to the organic polymer, the ratio of the amount of metal oxide of the inorganic/organic hybrid layer to the specific surface area of the uncoated metal pigment is in a range from 16.1 mg/m.sup.2 to 25 mg/m.sup.2, and the ratio of the amount of organic polymer of the inorganic/organic hybrid layer to the specific surface area of the uncoated metal pigment is in a range from 3.9 mg/m.sup.2 to 10.1 mg/m.sup.2.

15. The method according to claim 14, wherein at least one coating layer comprising at least one heteropolysiloxane is applied to at least one inorganic/organic hybrid layer, wherein the term metal oxide also comprises oxide hydrates and hydroxides, and the at least one heteropolysiloxane is prepared from at least one aminosilane and at least one silane selected from the group of alkylsilanes, vinylsilanes, and arylsilanes.

16. The method according to claim 14, wherein the reaction of the reactants of the inorganic/organic hybrid layer is carried out either a) first in a pH range from 2.5 to 6.8 and later in a pH range from 7.2 to 11.5, or b) first in a pH range from 7.2 to 11.5 and later in a pH range from 2.5 to 6.8.

17. An article comprising the pigment of claim 1, wherein the article is a cosmetic, a plastic or a coating material.

18. The pigment according to claim 9, wherein the at least one aminosilane of the heteropolysiloxane is selected from the group of the aminosilanes of formula (I):
R.sup.a1.sub.x1R.sup.b1.sub.y1R.sup.c1.sub.(4-x1-y1)Si(I), the R.sup.a1s independently of one another being selected from functional groups substituted by at least one nitrogen group, the functional group being selected from the group consisting of C1-C16 alkyl groups, C2-C8 alkenyl groups, C2-C8 alkynyl groups and phenyl groups, C7-C12 alkylaryl groups, and C7-C12 arylalkyl groups, the R.sup.b1s independently of one another being selected from the group consisting of C1-C16 alkyl groups, C2-C8 alkenyl groups, C2-C8 alkynyl groups, phenyl groups, C7-C12 arylalkyl groups, and C7-C12 alkylaryl groups, the aforesaid groups being unsubstituted, the R.sup.c1s independently of one another being selected from the group of the alkoxy groups, x1 being 1, 2 or 3, and y1 being selected from the group of the integers from 0 to (3x1).

19. The method according to claim 14, wherein the weight ratio of the amount of metal oxide of the coating to the amount of organic polymer of the inorganic/organic hybrid layer of the coated metal pigments is in a range from 2.5:1 to 9.0:1.

20. The method according to claim 14, wherein the ratio of the amounts of substance in moles of network former to organic polymer of the inorganic/organic hybrid layer of the coated metal pigments is in the range from 1:10 to 5:10.

21. The pigment according to claim 9, wherein the at least one heteropolysiloxane has been applied to the at least one inorganic/organic hybrid layer in precondensed form.

Description

EXAMPLES

Example 1

(1) 100 g of aluminum pigment in the form of a powder or in the form of a paste are admixed with isopropanol until there is 250 g of suspension in each case. The suspension is heated to 70 C., after which the constituents of the inorganic/organic hybrid layer (tetraethyl orthosilicate (TEOS), Dynasylan MEMO, TMPTMA, azobis(isobutyronitrile) (AIBN) and, if desired, allyl methacrylate or lauryl methacrylate) and 3 g of acetic acid in 30 g of distilled water are added. After 3 hours, 2.5 g of ethylenediamine in 50 g of isopropanol are added. After a further 2 hours, Dynasylan OCTEO and Dynasylan DAMO are added and the reaction mixture is stirred for 1 h before being cooled. The solid is isolated by filtration and collected as a paste.

(2) TABLE-US-00001 Amount Lauryl Allyl of meth- meth- BET pigment TEOS MEMO TMPTMA acrylate acrylate AIBN OCTEO DAMO Pigment [m.sup.2/g] [g] [g] [g] [g] [g] [g] [g] [g] [g] B 1-1 Mex 2192 4.0 100.00 35.0 0.4 1.8 0.4 0.0 0.1 0.9 1.0 B 1-2 Mex 3580 6.1 100.00 45.0 0.6 2.4 0.5 0.0 0.2 1.3 1.6 B 1-3 Mex 3580 6.1 100.00 40.1 0.8 3.6 0.7 0.0 0.3 1.3 0.7 B 1-4 Metallic 707 5.8 100.00 46.4 0.6 2.6 0.5 0.0 0.2 1.4 1.9 B 1-5 Mex 3580 6.1 100.00 42.1 0.5 2.2 0.8 0.0 0.2 1.3 1.6 B 1-6 Mex 3540 2.6 100.00 23.5 0.3 1.2 0.2 0.0 0.1 0.6 0.7 B 1-7 Mex 9160 6.5 100.00 52.4 0.7 3.1 0.6 0.0 0.3 1.4 1.6 B 1-8 Mex 3580 6.1 100.00 42.2 0.5 2.2 0.4 0.0 0.2 2.5 1.1 VB 1-9 Mex 3580 6.1 100.00 42.2 0.0 2.2 0.4 0.0 0.2 2.5 1.1 B 1-10 Mex 2192 4.0 100.00 45.0 0.5 2.1 0.0 0.0 0.2 1.3 1.2 B 1-11 Mex 3580 6.1 100.00 41.2 0.7 2.7 0.0 0.0 0.2 1.5 1.0 B 1-12 Mex 3540 2.6 100.00 44.1 0.7 2.6 0.0 0.0 0.1 1.0 0.9 B 1-13 Mex 9160 6.5 100.00 35.7 0.6 3.0 0.0 0.0 0.3 0.9 1.3 B 1-14 Mex 2192 4.0 100.00 42.5 0.5 2.9 0.0 0.6 0.1 1.2 1.5 B 1-15 Mex 3580 6.1 100.00 44.2 0.4 3.1 0.0 0.7 0.2 1.2 1.7 B 1-16 Mex 3540 2.6 100.00 41.7 0.7 2.2 0.0 0.5 0.2 1.5 1.2 B: Inventive example, VB: Comparative example

Example 2

(3) Inventive example 2-1 took place in analogy to the protocol of example 1. Comparative example 2-2 took place in accordance with the following protocol: 100 g of aluminum pigment in the form of a powder or in the form of a paste are admixed with isopropanol until there are 250 g of suspension in each case. The suspension is heated to 70 C., after which the tetraethyl orthosilicate (TEOS) and 3 g of acetic acid in 30 g of distilled water are added. After 3 hours, the additions of MEMO, TMPTMA, lauryl methacrylate, and AIBN take place. After a further 3 hours, 2.5 g of ethylenediamine in 50 g of isopropanol are added. After another 2 hours, Dynasylan OCTEO and Dynasylan DAMO are added, and the reaction mixture is stirred for 1 h before being cooled. The solid is isolated by filtration and collected as a paste.

(4) TABLE-US-00002 Amount Lauryl of meth- BET pigment TEOS MEMO TMPTMA acrylate AIBN OCTEO DAMO Pigment [m.sup.2/g] [g] [g] [g] [g] [g] [g] [g] [g] B 2-1 Mex 2156 3.4 200.00 45.9 0.6 2.4 0.5 0.2 1.0 1.3 VB 2-2 Mex 2156 3.4 200.00 45.9 0.6 2.4 0.5 0.2 1.0 1.3 B: Inventive example, VB: Comparative example

Example 3

(5) 100 g of aluminum pigment in the form of a powder or in the form of a paste are admixed with isopropanol until there are 250 g of suspension in each case. The suspension is heated to 70 C., after which the constituents of the inorganic/organic hybrid layer and 3 g of acetic acid in 30 g of distilled water are added. After 3 hours, 2.5 g of ethylenediamine in 50 g of isopropanol are added. After a further 2 hours, Dynasylan OCTEO and Dynasylan DAMO are added and the reaction mixture is stirred for 1 h before being cooled. The solid is isolated by filtration and collected as a paste.

(6) TABLE-US-00003 Amount Lauryl of meth- BET pigment TEOS MEMO TMPTMA acrylate AIBN OCTEO DAMO Pigment [m.sup.2/g] [g] [g] [g] [g] [g] [g] [g] [g] VB 3-1 Mex 2153 1.7 100.0 19.3 0.2 0.9 0.2 0.1 0.2 0.3 VB 3-2 Mex 2156 3.4 100.0 20.7 0.5 2.2 0.4 0.2 0.7 0.9 B 3-3 Mex 2156 3.4 100.0 23.1 0.6 2.7 0.5 0.2 1.0 0.4 B 3-4 Mex 3580 6.1 100.0 50.7 0.6 2.7 0.5 0.2 1.3 1.6 VB 3-5 Mex 3580 6.1 100.0 32.2 0.5 2.2 0.4 0.2 1.3 1.6 B 3-6 Mex 3580 6.1 100.0 42.2 0.5 2.2 0.4 0.2 1.3 0.7 B 3-7 Mex 2192 4.0 100.0 35.0 0.4 1.8 0.4 0.1 0.5 0.5 B 3-8 Metallic 707 5.8 100.0 38.0 1.0 4.3 0.8 0.3 1.5 0.6 VB 3-9 Metallux 9157 5.2 100.0 41.1 1.1 4.6 0.9 0.4 1.6 0.6 B 3-10 Metallux 9157 5.2 100.0 39.3 0.6 2.3 0.5 0.2 0.7 0.8 VB 3-11 Mex 2156 3.4 100.0 23.1 0.6 2.7 0.5 0.2 1.0 0.4 B 3-12 Mex 3580 6.1 100.0 53.9 0.5 2.2 0.4 0.2 1.3 0.5 B 3-13 Metallic 707 5.8 100.0 50.2 0.7 2.8 0.5 0.2 1.4 1.8 B 3-14 Metallux 9157 5.2 100.0 50.2 0.6 2.6 0.5 0.2 0.7 0.8 VB 3-15 Mex 2192 4.0 100.0 39.4 0.5 2.0 0.4 0.2 0.9 1.0 B: Inventive example, VB: Comparative example

Application Example 1

(7) For a stringent gassing test, 15 g of metal pigment paste with a solids content of 55 wt % were suspended in 11.0 g of butyl glycol with a stirring time of 5 minutes. This suspension was admixed with 14.4 g of colorless binder (ZK26-6826-402, manufacturer: BASF Coatings) and 0.6 g of 10% strength dimethylethanolamine solution (solvent: water) and stirred for 5 minutes.

(8) 21.96 g of the suspension were incorporated with stirring into a mixture of 195.0 g of mixing varnish for effect substance testing, milky/colorless (ZW42-6008-0101, manufacturer: BASF Coatings), 75.6 g of red aqueous basecoat tinting paste (ZU560-329-0001, manufacturer: BASF Coatings, containing red iron oxide, Fe.sub.2O.sub.3) and 6.0 g of black aqueous basecoat tinting paste (ZU42-5943-0001, manufacturer: BASF Coatings, containing black iron oxide, Fe.sub.2O.sub.3*FeO). Thereafter the pH of the suspension was adjusted to 9.0 using 10% strength dimethylethanolamine solution (solvent water).

(9) 265 g of the above composition were introduced into a gassing flask which was sealed with a twin-chamber gas bubble counter. The gas wash bottle was conditioned in a water bath at 40 C. for 1 hour, given a gastight seal, and tested over a maximum of 41 days. The resulting gas volume was read off on the basis of the displaced water volume in the upper chamber of the gas bubble counter. On evolution of at most 10 ml of hydrogen after 41 days, the test was deemed to have been passed. If the sample was not stable over the entire period, the time until outgassing of the sample was recorded.

(10) TABLE-US-00004 Metal oxide to Organic polymer surface area to surface area [mg/m.sup.2] [mg/m.sup.2] Result B 1-1 22.6 5.3 passed B 1-2 20.3 5.0 passed B 1-3 17.9 7.1 passed B 1-4 20.7 5.1 passed B 1-5 17.7 4.8 passed B 1-6 23.0 5.5 passed B1-7 21.1 5.6 passed B 1-8 17.7 4.2 passed VB 1-9 17.6 3.9 2 days B 2-1 17.5 4.2 passed VB 2-2 17.5 4.2 14 days VB 3-1 26.8 5.4 6 VB 3-2 12.8 6.2 2 B 3-4 20.2 4.8 passed VB 3-5 13.9 4.3 20 B 3-6 18.0 4.3 passed B 3-7 22.9 5.4 passed B 3-8 17.3 8.7 passed B 3-10 20.5 5.4 passed B 3-12 24.1 4.5 passed B 3-13 22.5 5.7 passed B: Inventive example, VB: Comparative example

Application Example 2

(11) The pigment samples were incorporated into a typical test varnish system (ZW42-1100, BASF, 0.35 wt % metal fraction) and the test applications were produced by spray coating on a primed steel panel. The film thickness in this case was 6 m. The basecoat was coated over with a commercial 1K clearcoat, followed by baking. The measurements were carried out using a BYK mac instrument (from Byk-Gardner).

(12) The flop index according to Alman is defined as follows in the relevant literature:
Flop index=2.69.Math.(L.sub.E1L.sub.E3).sup.111/L.sub.E2.sup.0.86
where L.sub.E1 is the luminance of the near-to-specular measuring angle (E1=15 to the specular angle), L.sub.E2 is the luminance of the measuring angle between near-to-specular and far-from-specular angle (E2=45 to the specular angle), and L.sub.E3 is the luminance of the far-from-specular measuring angle (E3=110 to the specular angle). The changes in flop between the respective inventive example and the corresponding comparative examples are listed below.

(13) The gloss measurement took place in a method based on DIN EN ISO 2813.

(14) The lower the numerical value of the flop index, the more weakly the desired light/dark flop is manifested.

(15) TABLE-US-00005 Metal oxide Organic polymer to surface to surface area area [mg/m.sup.2] [mg/m.sup.2] Flop VB 3-11 20.4 10.5 1.4 B3-53 19.7 10.1 0 B: Inventive example, VB: Comparative example

(16) TABLE-US-00006 Metal oxide to Organic polymer surface area to surface area [mg/m.sup.2] [mg/m.sup.2] Flop B 3-7 22.9 5.4 0 VB 3-15 37.6 5.6 0.7 B: Inventive example, VB: Comparative example

(17) TABLE-US-00007 Metal oxide to Organic polymer surface area to surface area [mg/m.sup.2] [mg/m.sup.2] Flop VB 3-9 22.5 11.3 0.7 B3-10 20.5 5.4 0 VB 3-14 25.6 6.1 0.3 B: Inventive example, VB: Comparative example