Method for material additive manufacturing of an inorganic filter support from a hot-melt composition and resulting membrane

1. A method for manufacturing a monolithic inorganic porous support having a porosity comprised between 10% and 60% and an average pore diameter ranging from 0.5 μm to 50 μm, using a 3D printing machine including an extrusion head movably mounted in space relative to and above a fixed horizontal plate, said 3D printing machine allowing the deposition of a string of inorganic composition to build, from a 3D digital model, a manipulable three-dimensional green structure intended to form the monolithic inorganic porous support, the method consisting of:

having the inorganic composition, said inorganic composition, including a first powdery solid inorganic phase in the form of particles with an average diameter comprised between 0.1 μm and 150 μm, and a second phase in the form of a matrix comprising a hot-melt polymer,

supplying the extrusion head of the 3D printing machine with the inorganic composition, said extrusion head being at a temperature allowing the extrusion of the inorganic composition to form the string,

building, using said string on said horizontal plate, the manipulable three-dimensional green structure in accordance with the 3D digital model,

placing this manipulable three-dimensional green structure in a heat treatment furnace in order to carry out a sintering operation at a temperature comprised between 0.5 and 1 times the melting temperature of a material forming the powdery solid inorganic phase.

2. The method according to claim 1 , wherein the consolidation of the manipulable three-dimensional green structure is accelerated as said string is extruded using a consolidation device.

3. The method according to claim 2 , wherein the consolidation device is a controlled cooling device causing the solidification of a hot-melt polymer contained in the matrix.

4. The method according to claim 2 , wherein the manipulable three-dimensional green structure is made with a tilt without implementing a supporting means.

5. The method according to claim 1 , wherein the powdery solid inorganic phase comprises one or more oxides, and/or carbides, and/or nitrides, and/or metals, chosen among titanium oxide, aluminum oxide, zirconium oxide, magnesium oxide, silicon carbide, titanium and stainless steel, and titanium oxide.

6. The method according to claim 1 , wherein the rheology of the inorganic composition is adjusted based on at least one of the following characteristics: the granularity of the powdery solid inorganic phase, the nature, and/or the proportion of the hot-melt polymer, the temperature of the inorganic composition.

7. The method according to claim 1 , wherein the manipulable three-dimensional green structure is in the form of several three-dimensional sub-structures detachable from each other.

8. The method according to claim 7 , wherein the manipulable three-dimensional green structure is in the form of several three-dimensional sub-structures connected and held together by a breakable bridge made using the string.

9. The method according to claim 1 , wherein the inorganic composition is in the form of a filament.

10. The method according to claim 1 , wherein the inorganic composition is in the form of a pellet.

11. A method for preparing a tangential filtration membrane, comprising manufacturing the monolithic inorganic porous support according to the method of claim 1 , in which is arranged a channel for the circulation of the fluid medium to be treated, followed by a step of creating a separating layer on the walls of the channel.

12. A monolithic inorganic porous support prepared according to the method of claim 1 withstanding an internal pressure of at least 30 bars without bursting.

13. A tangential filtration membrane prepared according to the method of claim 11 , withstanding an internal pressure of at least 30 bars without bursting.