BR-112021001128-B1 - Cement composition for 3D printing, 3D printing method, kit for preparing a cement composition for 3D printing, and 3D printing method implementing the kit.

BR112021001128B1BR 112021001128 B1BR112021001128 B1BR 112021001128B1BR-112021001128-B1

Abstract

The present invention relates to a novel cement composition for 3D printing comprising: 90% to 99.5% by weight of one or more cements selected from a Portland cement, an aluminous cement, a sulfoaluminous cement and a natural instant cement; and 0.5% to 10% by weight of a silicoaluminous filler having a specific surface area of at least 5 m2/g, as well as a method for implementing said composition.

Inventors

Olivier MARTINAGE
Damien Rogat
Laury Barnes-Davin

Assignees

VICAT

Dates

Publication Date: 20260310
Application Date: 20190725
Priority Date: 20180726

Claims (9)

1. Cement composition for 3D printing, characterized in that it comprises: - 90% to 99.5% by weight of a Portland cement and a sulfoaluminous cement; - 0.5% to 10% by weight of a silicoaluminous filler and/or silica fume having a specific surface area of at least 5 m2/g; and - wherein the cement composition additionally contains a limestone filler and/or a setting retarder.
2. Cement composition according to claim 1, characterized in that it contains 95% to 99.5% cement by weight.
3. Cement composition, according to claim 1 or 2, characterized in that it contains from 10% to 95% by weight relative to the total weight of cement of a Portland cement.
4. Cement composition, according to any one of claims 1 to 3, characterized in that it contains from 5% to 90% by weight relative to the total weight of cement of a sulfoaluminous cement.
5. Cement composition, according to any one of claims 1 to 4, characterized in that it contains from 0.5% to 5% by weight of silico-aluminous filler and/or silica fume having a specific surface area of at least 5 m2/g.
6. Cement composition, according to any one of claims 1 to 5, characterized in that the silico-aluminous filler is selected from natural pozzolans and calcined clays.
7. A 3D printing method, characterized in that it comprises the following steps: - contacting the cement composition, defined in any of claims 1 to 6, with water optionally added with superplasticizer and mixing the assembly; - pumping the composition thus obtained into the printing head and possibly adding a gripping actuator; - printing.
8. Kit for preparing a cement composition for 3D printing defined in any of claims 1 to 6, said kit characterized in that it comprises: - on the one hand, a Portland cement and, optionally, one or more of a limestone filler and/or a setting retarder; - and, on the other hand, a sulfoaluminous cement and optionally one or more of a limestone filler and/or a setting retarder; - the silicoaluminous filler having a specific surface area of at least 5 m2/g which may be present in the element of the kit containing the Portland cement and/or in the element of the kit containing the sulfoaluminous cement.
9. A 3D printing method implementing the kit defined in claim 8, characterized in that it comprises the following steps: - contacting the composition containing Portland cement, optionally with added superplasticizer, with water and mixing the assembly; and, separately, placing the composition containing sulfoaluminous cement in contact with water, optionally with added superplasticizer, and mixing the assembly; - pumping each of the compositions thus obtained into the print head, placing them in contact, optionally in the presence of a gripping actuator; - printing.

Description

[001] The present invention relates to a new cement composition for 3D printing as well as to a method of 3D printing using said cement composition. [002] 3D printing or three-dimensional printing refers to methods of manufacturing parts in volume by adding or agglomerating material. In the industrial sector, it is also called additive manufacturing. [003] Additive manufacturing can be divided into several stages: - design of the 3D object in the form of a drawing using a computer-aided design (or CAD) tool; - processing of the 3D file obtained by specific software ("slicing" software) that organizes the slicing of the different layers necessary for the production of the part, and generation of a control file, the G-Code, which contains all the information to move the print head precisely; then - the manufacturing of the object slice by slice via execution of the G-Code by the machine that deposits or solidifies the material layer by layer until the final part is obtained. [004] The principle remains close to that of a conventional 2D printer, except that layer stacking allows you to create volume. [005] Originally, in the early 2000s, 3D printing began with the use of heated resins and was primarily used for rapid prototyping. Subsequently, innovative techniques using new materials such as plastic (PLA or ABS), wax, metal (aluminum, steel, titanium, platinum), plaster of Paris, ceramics, and even glass, quickly emerged. Time savings and manufacturing precision allow for the production of parts in small series. [006] There are many applications for 3D printing. Initially confined to prototyping and visualization of ergonomics for architectural or design studies, then to equipment and prostheses, it has gradually gained industrial sectors ranging from the production of auto parts, airplanes, buildings, consumer goods, etc. [007] Depending on the type of material used, there are two main manufacturing techniques: - material deposition or material fusion in the case of plastic material: the plastic filament is heated to the level of the print head which allows its extrusion and then hardens very quickly after being applied; or - laser sintering used mainly to print metal: a laser hits a metal powder locally generating cohesion between the powder particles and the formation of a metal structure by sintering. [008] 3D printing from cementitious materials to design structures more efficiently is also growing. The printing method used is similar to the method used for plastic materials, except that extrusion and hardening are not provided by heating in the print head. [009] In the case of printing cementitious material, whether cement paste, mortar or concrete, the material in the fluid state is pumped into a printing head where it is subjected to a sudden change in its rheology that allows it to be extruded into a bead of material that does not yield and supports its own weight. [010] Cement ink is prepared upstream of the printer in a mixer. It can be prepared in batches or via a continuous method. It is then pumped to the print head. [011] In the print head, the ink is mixed with an adjuvant that suddenly accelerates its setting. This mixing or blending can be carried out using two technologies: - the static mixer: this is a tube within which numerous obstacles interfere with the ink flow. The turbulence thus generated makes it possible to homogenize the various constituents of the ink before extrusion; or - the dynamic mixer consisting of a propeller (rotor) rotating in a tube (stator) and driven by a motor. This is the most efficient blending technique. [012] At the end of this mixing, the ink is extruded through a nozzle into a bead of material of a size defined by the material flow rate and the speed of movement of the print head, allowing the structure to be printed following the G-Code. [013] To be usable in 3D printing, a cementitious ink must therefore meet three main requirements: - immediately after its preparation, the composition must be fluid enough to be pumpable but not to segregate (the so-called “pumpability” criterion); - during its passage through the print head, the composition must be able to undergo a sudden change in rheology to make it much more viscous and prevent the mortar bead from spreading after extrusion; and - finally, after passing through the print head, the already extruded/printed beads must have sufficient strength to support the weight of the new extruded layer (the so-called “constructability” criterion). [014] Until now, in most cases, cement-based inks containing essentially a Portland binder have been used. To do this, Portland cement is used as a suspension in water. However, besides the fact that upon contact with water, hydration begins to cause the cement to harden, not without causing difficulties in the 3D printing process, the increase in strength of the ink thus prepared is slow, which limits the printing speed. [015] Alternatives to using Portland binder to pre