Paste-like composition and method for producing three-dimensional structures or structural elements on substrate surfaces

Abstract

A pasty composition for the manufacture of three-dimensional structures or structural elements on the surface of a substrate is formed together with a polymer as an organic component B1, and a powdery material that makes up a proportion of solid in the range of 60 mass % to 95 mass % in the composition, and at least two mutually different solvents C1 and C2 that form a solvent mixture. A first solvent C1 has a boiling temperature here that is lower than the boiling temperature of the further solvent or solvents C2.

Claims

1. A method of manufacturing three-dimensional structures or structural elements in which a pasty composition is printed in the form of at least one layer onto the surface of a substrate and a temperature increase is observed in this process at which a first solvent C1 evaporates but a further solvent C2 does not evaporate so that the viscosity of the pasty composition is increased, and subsequently a mechanical processing or plastic deformation is carried out in which a predefined outer contour of the respective structure or of a respective structural element is achieved and subsequently a thermal treatment is carried out in which all organic components including the further solvent C2 are removed and a powdery material is sintered, wherein the pasty composition comprises a polymer as the organic component B1, and the powdery material that makes up a proportion of solid in the range of 60 mass % to 95 mass % in the composition, and at least two mutually different solvents C1 and C2 that form a solvent mixture, wherein the first solvent C1 has a boiling temperature that is lower than the boiling temperature of the further solvent C2; wherein the first solvent C1 is selected from hexane, cyclohexane, methyl acetate, ethyl acetate, benzene, methyl ethyl ketone, isopropanol, ethanol, and methanol; and the further solvent C2 is selected from butyl carbitol, monoethylene glycol, diethylene glycol, 1,2-propanediol, butanol, 3-methoxy-1-butanol, terpene oil, or pine oil; and the organic polymer B1 is selected from ethyl cellulose of the type N-4 to N-300, methyl methacrylates, n-butyl methacrylates, acrylic polymers or alkyd resins; and wherein the pasty composition comprises one or more further organic components B2 selected from the group consisting of 1,2,3,4-tetrahydronaphthalene, dimethyl cyclohexyl phthalate, naphthalene, N-oleoylsarcosine, 1,2-cyclohexane dicarboxylic acid diisononylester, 2,4,7,9-tetramethyl-5-decyne-4,7-diol, trihydroxystearin, octadecylamine, triethanolamine, oleic acid and stearic acid.

2. The method in accordance with claim 1, characterized in that the printing takes place by means of silk screen printing, template printing, tampon printing, or dispensing with a respective layer thickness of at least 100 μm; and/or in that a height to width ratio α in the range 0.05≤a≤1.0 is observed.

3. The method in accordance with claim 1, characterized in that, at a temperature in the range from 20° C. to 30° C., a viscosity in the range from 40 Pas to 300 Pas is observed with a shear rate γ of 10 s.sup.−1 and a viscosity in the range from 10 Pas to 35 Pas is observed with a shear rate γ of 100 s.sup.−1.

4. The method in accordance with claim 1, characterized in that the first solvent and the at least one further solvent, C1 and C2, are contained with a proportion in the range 3 mass % to 40.0 mass %.

5. The method in accordance with claim 1, characterized in that 0.05 mass % to 6.0 mass % of plasticizer, softener, leveling agent, wetting additive or dispersion additive B2 and 0.05 mass % to 8.0 mass % of organic polymers B1 are contained in the composition.

6. The method in accordance with claim 1, characterized in that an oxide, a mixed oxide, a spinel, a perovskite, a metal and/or a glass or a mixture thereof is contained as the powdery material.

7. The method in accordance with claim 1, characterized in that the powdery material having a mean particle size d.sub.50 in the range between 0.1 μm and 10 μm is contained.

Description

EXAMPLE 1

(1) Preparation of a Pasty Composition for Manufacturing a Web-like Contact Layer Between an Interconnector and a Cathode of a High Temperature Fuel Cell

(2) 50 g 1,2,3,4-tetrahydronaphthalene as B2, 5 g benzyl alkyl phthalate as B2, 3 g butyl glycolate as C2, 0.5 g naphthalene as B2, 36.5 g terpene oil as a further solvent C2, 2 g ethyl cellulose of the type N-7 as B1, and 6 g ethyl acetate as C1 are mixed and heated in a closed agitator vessel. An organic mixture is obtained that is pourable at room temperature and that could be stored without any greater change of its flow properties. 80 g perovskite powder (e.g. La.sub.0.8Sr.sub.0.2Mn.sub.0.9Co.sub.0.1O.sub.3) having a mean particle diameter d.sub.50 of 5 μm are pasted into 20 g of the above-named organic mixture with the aid of an agitator, dissolver, mortar mill, or speed mixer. The obtained pasty composition is subsequently homogenized in a triple roller mechanism (roller mill). The prepared paste is applied to a surface of an interconnector as a substrate by means of silk screen printing or template printing or by means of a dispenser. After drying in which C1 as the first solvent has at least been completely evaporated at 25-75° C., the structure formed with the pasty composition on the cathode surface can be mechanically treated at its surface and in so doing the surface can preferably be smoothed and leveled before a heat treatment leading to sintering is carried out.

EXAMPLE 2

(3) On the preparation of a pasty composition for a contact layer formed with webs between an interconnector and a cathode of the high temperature fuel cell, 15 g methyl methacrylate and/or n-butyl-methacrylate as an organic polymer B1, 80 g terpene oil as a further solvent C2, 2 g butyl carbitol as a further solvent C2, and 5 g isopropanol as a solvent C1 are mixed and heated in a closed agitator vessel. An organic mixture is obtained that is pourable at room temperature and that could be stored without any greater change of its flow properties. 80 g perovskite powder (e.g. La.sub.0.8Sr.sub.0.2Mn.sub.0.9Co.sub.0.1O.sub.3) having a mean particle size d.sub.50 of 5 μm and 1 g, 2,4,7,9-tetramethyl-5-decyne-4,7-diol as B2 are pasted into 20 g of this organic mixture with the aid of an agitator mechanism, a dissolver, a mortar mill, or a speed mixer. The pasty composition is subsequently homogenized with the aid of a roller mill. The prepared paste is applied to a surface of the interconnector as a substrate by means of silk screen printing or template printing or by means of a dispenser. After drying, in which at least the first solvent C1 has been almost completely evaporated, it can be processed by plastic deformation mechanically or in a shaping manner by means of a shaping tool that can be placed on before a heat treatment leading to sintering is carried out.

(4) The three-dimensional web structure obtained in accordance with Examples 1 or 2 has a structural width of 3 mm and a layer thickness of the web lines in the range between 200 μm and 550 μm, preferably 300 μm to 350 μm. To realize these structures, a pasty composition in accordance with the invention was used whose viscosity was initially at approximately 60 Pas and whose viscosity value increases to 110 Pas after drying at air for 10 min.