PROCESS FOR PRODUCING STRUCTURED COATINGS

Abstract

The present invention, relates, to a process, for producing structured coatings, in which a coating composition comprising at least one inorganic binder, at least one oxide pigment which, after addition of a mixture consisting of 15 ml of 1 M oxalic acid and 15 ml of 20% aqueous hydrochloric acid based on 1 g of substance, under standard conditions, leads to a temperature rise of at least 4° C., and at least one solvent is applied to a substrate, the resulting coating composition film is partially coated with a photoresist and the substrate coated with the coating composition and the photoresist is treated with an acid, to the structured layers obtainable by the process and to the use thereof.

Claims

1. A process for producing a structured coating, comprising: applying a. a coating composition comprising i. at least one inorganic binder, ii. at least one oxide pigment which, after addition of a mixture consisting of 15 ml of 1 M oxalic acid and 15 ml of 20% aqueous hydrochloric acid based on 1 g of substance, under standard conditions, leads to a temperature rise of at least 4° C., and iii. at least one solvent to a substrate, to obtain a coating composition film on the substrate, b. partially coating the resulting coating composition film with a photoresist, and c. treating the substrate coated with the coating composition film and the photoresist with an acid.

2. The process according to claim 1, wherein the inorganic binder has the generic formula Si.sub.aR'.sub.bO.sub.c(OR.sup.2).sub.d with a≧2, b≧0, c≧1, d≧5 and R.sup.1 and R.sup.2=organic radical.

3. The process according to claim 1, wherein the pigment is a pigment based on a mixed oxide of a (semi)metal in more that one oxidation state and/or a pigment based on at least two mixed oxides of at least two (semi)metals each in one or more oxidation states.

4. The process according to claim 3, wherein said pigment is a mixed iron-manganese oxide.

5. The process according claim 4, wherein said pigment is a copper-containing mixed iron-manganese oxide.

6. The process according to claim 5, wherein the mixed iron-manganese oxide is obtainable via a calcination of manganese(II) oxide, manganese(III) oxide, iron(II) oxide and iron(III) oxide and copper(II) oxide.

7. The process according to claim 6, wherein the pigment is assigned to the group of pigments having the Colour Index designation Pigment Black 26.

8. The process according to claim 1, wherein a proportion of oxide pigment, based on the total mass of the composition, is 10%-50% by weight.

9. The process according to claim 1, wherein the at least one solvent is selected from the group consisting of an alcohol, an alkyl ester, an alkoxy alcohol, an alkoxyalkyl ester and mixture thereof.

10. The process according to claim 1, wherein the acid used is aqueous oxalic acid in a concentration of 0.3 to 2.5 mol/l, aqueous hydrochloric acid 3.0-12.0 mol/l or mixtures having proportion by volume ratios of 1:2 to 2:1 of 1 M aqueous oxalic acid and 6 M aqueous HCl.

11. The process according to claim 1, wherein after the acid treatment a. the photoresist is removed, and b. the remaining coating is cured.

12. The process according to claim 1, wherein after the acid treatment a. the pigment-free coating is removed partially or completely, b. the photoresist is removed, and c. the remaining coating is cured.

13. A structured coating obtainable by a process according to claim 1.

14. An electronic component or an automobile part, comprising: the structured coating of claim 13.

Description

EXAMPLES

Example 1: Making up the Sol-Gel Matrix

[0062] TEOS (15.44 wt %) and MTES (66.18 wt %) are mixed. [0063] Subsequently added thereto are demineralized H2O (9.18 wt %) and Hordaphos CCMS phosphoric ester (0.02 wt %). [0064] The mixture is stirred on a stirrer plate overnight. [0065] Then demineralized H.sub.2O (9.18 wt %) is added again. [0066] The sol-gel mixture ripens for 2 days (with stirring).

Example 2: Production of the Dispersion

[0067] The 1-methoxy-2-propanol solvent (57.85 wt %) is initially charged, in order to dilute the sol-gel mixture to the suitable solids concentration. [0068] Then 15.03 wt % of the sol-gel mixture is added. [0069] The TEGO Dispers 710 dispersing and wetting additive (2.10 wt %) is added. [0070] Lastly, the spinel black “deepest black (Fe,Mn)(Fe,Mn).sub.2O.sub.4” from Kremer Pigmen GmbH & Co. KG is added (amount 25.02 wt %). [0071] For the dispersion by means of an agitated mixer (Scandex), about 30 g of zirconium oxide grinding beads of size 0.4 to 0.6 mm are added. [0072] The dispersion mixture is dispersed for at least 2 hours, but better 10 hours, in the agitated mixer. [0073] After the dispersion, the grinding beads are removed by sedimentation or filtering.

Example 3: Substrate Coating

[0074] As substrates to be coated, glass substrates are used. [0075] Prior to coating, the glass substrates are cleaned with organic solvent (isopropanol) rinsed with DI water and then blown dry with nitrogen. [0076] The dispersion is applied by means, of a spin-coating method with the following parameters: 10 sec at 500 rpm, then 30 sec at 2000 rpm. [0077] The structuring is preceded by a prebake step, in order to gradually remove the solvent and, prevent cracking of the layer (10 min at 100° C. on the hotplate).

Example 4: Application of the Photoresist; UV Exposure

[0078] By means of a spin-coating method, the photoresist AZ 1514H from MicroChemicais GmbH is applied to the coated glass substrates with the following parameters: 30 sec at 2000 rpm. [0079] The curing takes place on the hotplate at 180° C. for 80 seconds. [0080] After the curing, the substrates are exposed to UV light through a mask in the mask aligner for 10 seconds.

Example 5: Development

[0081] The exposed glass substrates are developed for 2.5 minutes in a bath containing AZ Developer from MicroChem GmbH. [0082] Thereafter, the glass substrates are rinsed with DI water and blown dry with nitrogen.

Example 6: Structuring

[0083] The glass substrates are treated in a first step in a bath consisting of 1 M oxalic, acid and 20% aqueous hydrochloric acid (1:1) for 5 minute [0084] Thereafter, the glass substrates are rinsed with DI water and blown dry with nitrogen: [0085] The glass substrates are treated in a second step in a bath consisting of 0.5 M sodium hydroxide solution for 40 seconds. [0086] Thereafter, the glass substrates are rinsed with DI water and blown dry with nitrogen.

Example 7: Curing

[0087] The curing takes place on the hotplate at C for 5 minutes.