FR3056577A1 - Composition and method for manufacturing vitreous objects - Google Patents

Composition and method for manufacturing vitreous objects Download PDF

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Publication number
FR3056577A1
FR3056577A1 FR1659132A FR1659132A FR3056577A1 FR 3056577 A1 FR3056577 A1 FR 3056577A1 FR 1659132 A FR1659132 A FR 1659132A FR 1659132 A FR1659132 A FR 1659132A FR 3056577 A1 FR3056577 A1 FR 3056577A1
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Prior art keywords
preferably
silica
composition
range
water
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French (fr)
Inventor
Cedric Boissiere
Marco FAUSTINI
Lionel Nicole
David Grosso
Guillaume Naudin
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Centre National de la Recherche Scientifique CNRS
Universite Pierre et Marie Curie (Paris 6)
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Centre National de la Recherche Scientifique CNRS
Universite Pierre et Marie Curie (Paris 6)
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Priority to FR1659132A priority Critical patent/FR3056577A1/en
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Publication of FR3056577A1 publication Critical patent/FR3056577A1/en
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    • CCHEMISTRY; METALLURGY
    • C03GLASS; MINERAL OR SLAG WOOL
    • C03BMANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
    • C03B19/00Other methods of shaping glass
    • C03B19/12Other methods of shaping glass by liquid-phase reaction processes
    • CCHEMISTRY; METALLURGY
    • C03GLASS; MINERAL OR SLAG WOOL
    • C03CCHEMICAL COMPOSITION OF GLASSES, GLAZES, OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C1/00Ingredients generally applicable to manufacture of glasses, glazes, or vitreous enamels
    • C03C1/006Ingredients generally applicable to manufacture of glasses, glazes, or vitreous enamels to produce glass through wet route
    • CCHEMISTRY; METALLURGY
    • C03GLASS; MINERAL OR SLAG WOOL
    • C03CCHEMICAL COMPOSITION OF GLASSES, GLAZES, OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C1/00Ingredients generally applicable to manufacture of glasses, glazes, or vitreous enamels
    • C03C1/10Ingredients generally applicable to manufacture of glasses, glazes, or vitreous enamels to produce uniformly-coloured transparent products
    • CCHEMISTRY; METALLURGY
    • C03GLASS; MINERAL OR SLAG WOOL
    • C03CCHEMICAL COMPOSITION OF GLASSES, GLAZES, OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C14/00Glass compositions containing a non-glass component, e.g. compositions containing fibres, filaments, whiskers, platelets, or the like, dispersed in a glass matrix
    • C03C14/004Glass compositions containing a non-glass component, e.g. compositions containing fibres, filaments, whiskers, platelets, or the like, dispersed in a glass matrix the non-glass component being in the form of particles or flakes
    • CCHEMISTRY; METALLURGY
    • C03GLASS; MINERAL OR SLAG WOOL
    • C03CCHEMICAL COMPOSITION OF GLASSES, GLAZES, OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C4/00Compositions for glass with special properties
    • C03C4/02Compositions for glass with special properties for coloured glass

Abstract

The present invention relates to the field of materials. In particular, the present invention relates to a novel composition obtained by mixing: a matrix comprising: at least one source of silica, chosen from colloidal silica or one of its precursors; at least one base; some water ; in which ; - The base molar ratio on silica source is in a range of 0.2 to 1; the molar ratio of water to silica source is in the range of 5 to 20; and at least one reactive additive selected from: (1) a zeolite or a derivative thereof, and (2) a mixed silicon alkoxide or an alkoxide of a transition metal; the reactive additive being in a range of 0.1 to 50% by weight relative to the total mass of the composition. The present invention also relates to a low-temperature vitreous object manufacturing method from the composition of the invention.

Description

Holder (s): UNIVERSITE PIERRE ET MARIE CURIE - PARIS 6 (UPMC), NATIONAL CENTER FOR SCIENTIFIC RESEARCH.

Extension request (s)

Agent (s): ICOSA.

FR 3 056 577 - A1

154) COMPOSITION AND PROCESS FOR THE MANUFACTURE OF VITREOUS OBJECTS.

The present invention relates to the field of materials. In particular, the present invention relates to a new composition obtained by mixing: a matrix comprising:

- At least one source of silica, chosen from colloidal silica or one of its precursors; at least one base; some water; in which;

the base molar ratio on source of silica is in a range from 0.2 to 1;

the water to silica source molar ratio is in a range from 5 to 20;

and at least one reactive additive chosen from: (1) a zeolite or one of its derivatives, and (2) a mixed silicon alkoxide or an alkoxide of a transition metal; the reactive additive being in a range from 0.1 to 50% by mass relative to the total mass of the composition.

The present invention also relates to a method of manufacturing glassy object at low temperature from the composition of the invention.

Figure FR3056577A1_D0001

COMPOSITION AND PROCESS FOR THE MANUFACTURE OF VITREOUS OBJECTS

FIELD OF THE INVENTION

The present invention relates to the field of materials. In particular, the present invention relates to a new composition particularly suitable for the manufacture of glassy objects at low temperature; preferably by additive manufacturing techniques.

STATE OF THE ART

3D printing, also known as "additive manufacturing", brings together a set of computer-aided technologies that allow 3D objects to be manufactured from a model by assembling successive layers of the same material. For example, laser sintering of metallic powders or the projection of material are among the best known techniques.

If 3D printing has been very popular with the general public and manufacturers since the end of the 20th century, the field of application is nevertheless strongly dependent on the materials that can be deposited by these methods.

To date, there are mainly four main families of materials suitable for 3D printing:

polymers (in particular, thermoplastics); certain metals and their alloys; ceramic or composite materials; and biological or biocompatible materials.

Although other materials can also be used for the manufacture of specific objects, in wax or chocolate for example, 3D printing has not, however, been able to supply the market with manufactured glass objects so far. Indeed, these objects are essentially obtained by traditional glass manufacturing techniques such as molding or blowing, which require high temperatures.

Recently, attempts have been made to develop 3D printing systems suitable for the production of glass objects. For example, MIT (US2015 / 0307385) has developed a prototype for depositing molten glass at very high temperatures (above 1000 ° C). However, the need to exceed the melting point of the glass in order to be able to shape it constitutes a significant energy loss, generates high production costs and risks in terms of personal and operational safety. Other additive glass manufacturing techniques have been developed, notably by sintering glass particles or by using glass paste. However, the implementation of these techniques requires high temperatures, does not allow the transparency of the glass to be preserved and leads to objects of low optical quality.

There is therefore a need to provide alternatives to the methods of manufacturing glassy objects, in particular of manufacturing glass objects. In particular, there is a need to develop manufacturing methods which are easy to implement in complete safety and which have greater versatility than traditional techniques.

In addition, the use of 3D printing techniques requires specific physicochemical properties of the composition to be shaped. The difficulty consists in particular in having a composition (1) sufficiently fluid to be able to implement the method, and (2) capable of hardening quickly so as to retain the shape of the object.

There is therefore a need to provide compositions adapted to the constraints of additive manufacturing processes.

Surprisingly, the Applicant has highlighted a new composition suitable for the manufacture of glassy objects at low temperature. In particular, this composition makes it possible to provide glassy objects having satisfactory optical quality and physicochemical stability after cooling. This composition also makes it possible, by means of the incorporation of various additives into the composition, to provide vitreous objects having satisfactory physicochemical properties after cooling, such as good temperature resistance, chemical stability and improved mechanical properties, the possibility of obtaining colored products and / or of modulating the hydrophobicity of the glassy object (for example to obtain self-cleaning or anti-fog properties on the object).

Advantageously, this composition is suitable for any process for manufacturing a glassy object, for example for manufacturing a glass object, including additive manufacturing techniques.

ABSTRACT

The present invention therefore relates to a composition obtained by mixing: a matrix comprising:

at least one source of silica, chosen from colloidal silica or one of its precursors; at least one base; some water ;

in which ;

the molar ratio base to source of silica is in a range from 0.2 to 1, preferably from 0.3 to 0.5;

the water to silica source molar ratio is in a range from 5 to 20, preferably from 5 to 11;

and at least one reactive additive chosen from:

(1) a zeolite or one of its derivatives; and (2) a mixed silicon alkoxide or a transition metal alkoxide;

said reactive additive being in a range of 0.1 to 50%; preferably 5 to 40%; more preferably from 10 to 35%; even more preferably from 15 to 30%, by mass relative to the total mass of the composition.

According to one embodiment, the reactive additive is a zeolite having a silica to aluminum molar ratio of more than 0 to 50; preferably from 1 to 5.

According to one embodiment, the zeolite is a particle with a diameter of more than 0 to 200 nm; preferably from 1 nm to 100 nm; more preferably, from 10 to 50 nm.

According to one embodiment, the matrix has a dynamic viscosity measured at 20 ° C -1 8 under constant shear stress at 5 s' of between 10,000 and 10 mPa.s; preferably from 10 5 to 10 7 mPa.s; more preferably from 5.10 5 to 2.10 6 mPa.s.

The invention also relates to a process for manufacturing a glassy object comprising:

a step of shaping the composition as described above, at a temperature in a range from 20 ° C to 100 ° C; preferably at a temperature of 30 ° C to 80 ° C; more preferably from 40 to 70 ° C; and a polycondensation reaction step.

According to one embodiment, the method of the invention further comprises the following preliminary steps:

(a) a step of preparing a matrix comprising the mixture:

at least one source of silica chosen from colloidal silica or one of its precursors; at least one base; and water;

in which ;

the molar ratio base to source of silica is in a range from 0.2 to 1, preferably from 0.3 to 0.5;

the water to silica source molar ratio is in a range from 5 to 20, preferably from 5 to 11;

(b) a step of mixing the matrix of step (a) with at least one reactive additive chosen from:

(1) a zeolite or one of its derivatives; and (2) a mixed silicon alkoxide or a transition metal alkoxide;

said reactive additive being in a range of 0.1 to 50%; preferably 5 to 40%; more preferably from 10 to 35%; even more preferably from 15 to 30%, by mass relative to the total mass of the composition.

According to one embodiment, the shaping of the composition is carried out by an additive manufacturing technique, by molding or by blowing glass; preferably, the composition is shaped by an additive manufacturing technique; more preferably, by the molten filament deposition method (FDM), by the direct ink writing method (DIW), or by a combination of these methods.

The present invention also relates to a glassy object capable of being obtained by the method as described above.

According to one embodiment, the object is transparent.

The present invention also relates to a mixing module for the preparation of the composition as described above, comprising:

a first compartment comprising a mixture:

at least one source of silica, chosen from colloidal silica or one of the precursors;

at least one base; and water ;

in which ;

the molar ratio base to source of silica is in a range from 0.2 to 1, preferably from 0.3 to 0.5;

the water to silica source molar ratio is in a range from 5 to 20, preferably from 5 to 11; and a second compartment comprising at least one reactive additive chosen from:

(1) a zeolite or one of its derivatives; and (2) a mixed silicon alkoxide or a transition metal alkoxide;

said reactive additive being in a range of 0.1 to 50%; preferably 5 to 40%; more preferably from 10 to 35%; even more preferably from 15 to 30%, by mass relative to the total mass of the composition contained in the first compartment.

DEFINITIONS

In the present invention, the terms below are defined as follows:

"Base" relates to a chemical compound capable of capturing one or more protons (Bronsted base). In the present invention, the base is a chemical salt capable of releasing hydroxyl anions (HO-), for example in water; preferably, the base is chosen from organic bases and inorganic bases such as KOH, NaOH, CsOH, RbOH and LiOH; more preferably, the base is KOH.

"Approximately", placed before a number, means more or less 10% of the nominal value of this number.

“DIW” (“Direct Ink Writing”): relates to an additive manufacturing technique relating to the deposition of a filament of an ink loaded with solid materials, for example a ceramic suspension, which is extruded from a nozzle, either in the form of a filament or in the form of droplets.

"Additive manufacturing": concerns all the processes for manufacturing objects or parts by adding computer-aided material.

"FDM" ("Fused Deposition Modeling"): relates to an additive manufacturing technique relating to the deposition of a molten wire.

“Transition metal alkoxide”: relates to a chemical compound of general formula M- (OR) x - (F) y in which R is a linear or branched alkyl group; M is a metal or metalloid other than silicon; and F is any organic group, preferably a linear or branched alkyl group; x is in a range from 1 to 6, preferably from 1 to 3; and is therein in a range from 0 to 6, preferably from 1 to 3. Preferably, the alkyl group R comprises from 1 to 5 carbon atoms, more preferably 1 or 2 carbons. Preferably, F is a linear or branched alkyl group comprising from 1 to 5 carbon atoms, more preferably or 2 carbons. In the present invention, the alkoxide is chosen from silicon alkoxides and transition metal alkoxides.

“Mixed silicon alkoxide”: relates to a chemical compound of general formula Si (OR) x - (F) 4_ x in which R is a linear or branched alkyl group; and F is any organic group other than the group -OR, preferably a linear or branched alkyl group; x is in a range from 1 to 3. Preferably, the alkyl group R comprises from 1 to 5 carbon atoms, more preferably 1 or 2 carbons. Preferably, F is a linear or branched alkyl group comprising from 1 to 5 carbon atoms, more preferably 1 or 2 carbons.

“Silicon tetra-alkoxide”: relates to a chemical compound of general formula Si (OR) 4 in which R is a linear or branched alkyl group comprising from 1 to 5 carbon atoms, more preferably 1 or 2 carbons.

"Molding": refers to any technique allowing an object to be produced by depositing a raw material in a mold. In the present invention, the term “molding” is understood to mean the production of a glass object by depositing the composition of the invention in a mold.

"Transparent": refers to a physical property allowing a material to let light through without it being dispersed by it. In the present invention, the glass object is transparent for wavelengths in the visible range (i.e. between about 400 nm to 800 nm).

“Glass”: concerns an amorphous (non-crystalline) solid network, generally transparent. In the present invention, a glass is an amorphous network of silica.

"Viscosity": relates to a physical parameter relating to the uniform flow resistance and without turbulence occurring in the mass of a material during the application of a stress.

"Glassy": relates to a characteristic of a partially or completely amorphous solid network exhibiting a glass transition, that is to say a characteristic change of state, observed on cooling, during the transition from a supercooled liquid phase to a glassy and / or warming phase, during the transition from a glassy phase to a supercooled liquid phase. A glassy object may be partially or completely transparent. In the present invention, the glassy materials can be, for example, a glass or a glass ceramic.

“Vitroceramic”: concerns an amorphous solid network partially crystallized or comprising crystallized components, such as fillers or additives. In the present invention, the amorphous part of a glass ceramic is an amorphous network of silica.

"Silica": refers to silicon dioxide (SiCL). The silica can be in crystalline or amorphous form.

"Zeolite" or "Zeolite": refers to a crystallized and porous aluminosilicate. According to one embodiment, the zeolite is an aluminosilicate having a silica to aluminum molar ratio included in a range going from more than 0 to 50; preferably from 1 to 5.

DETAILED DESCRIPTION

The present invention therefore relates to a composition obtained by mixing: a matrix comprising:

at least one source of silica, chosen from colloidal silica or one of its precursors; at least one base; some water ;

in which ;

the base to silica source molar ratio is in a range from 0.2 to 1;

the water to silica source molar ratio is in a range from 5 to 20.

and a reactive additive chosen from:

(1) a zeolite or one of its derivatives; and (2) a molecule capable of hydrolyzing and then reacting with the strong base of the matrix to form an associated weak base;

the reactive additive being in a range of 0.1 to 50% by mass relative to the total mass of the composition.

According to one embodiment, the source of silica is colloidal silica.

According to one embodiment, the source of silica is a silica precursor such as dry silica, pyrogenic silica, sand, silicates, or silicon tetra-alkoxides.

According to one embodiment, the source of silica or of silica precursor is in the form of particles; preferably nanoparticles.

According to one embodiment, the composition comprises at least one base chosen from inorganic bases and / or organic bases. According to one embodiment, the base is chosen from tetraalkylammonium hydroxides, potassium hydroxide (KOH), sodium hydroxide (NaOH), cesium hydroxide (CsOH), rubidium hydroxide (RbOH) and lithium hydroxide (LiOH); preferably, the base is potassium hydroxide (KOH).

According to one embodiment, the composition comprises organic and / or inorganic bases. According to one embodiment, the composition comprises a mixture of organic and inorganic base chosen from potassium hydroxide-trimethylammonium hydroxide (KOH-TMAOH), sodium hydroxide-trimethylammonium hydroxide (NaOH-TMAOH), potassium hydroxide-hydroxide tripropylammonium (KOH-TPAOH), sodium hydroxide-tripropylammonium hydroxide (NaOH-TPAOH), potassium hydroxide-tetraethylammonium hydroxide (KOH-TEAOH) and potassium hydroxide-tetrapropylammonium hydroxide (KOH-TPAOH). According to one embodiment, the molar percentage of organic base is in a range from more than 0 and 40%, relative to the total amount of base in the composition. Advantageously, the mixture of an organic base and an inorganic base makes it possible to stabilize the silica network in the composition of the invention.

According to one embodiment, the molar ratio of the amount of base to the amount of silica is in a range from 0.2 to 1; preferably from 0.3 to 0.5. In one embodiment, the base to silica ratio is equal to 0.48.

According to one embodiment, the molar ratio of the amount of water to the amount of silica is in a range from 5 to 20; preferably from 5 to 11.

According to one embodiment, the reactive additive is zeolite or one of its derivatives; preferably the reactive additive is zeolite. According to one embodiment, the composition comprises a zeolite derivative; preferably an aluminosilicate cation exchanger material.

According to one embodiment, the zeolite is a chemical compound having a silica to aluminum molar ratio of more than 0 to 50; preferably from 1 to 5.

According to one embodiment, the zeolite is a particle with a diameter of more than 0 to 200 nm; preferably from 1 nm to 10,000 nm; more preferably, from 10 to 200 nm; very preferably, from 10 nm to 50 nm.

According to one embodiment, the reactive additive is a silica-based particle containing at least one of the following elements: aluminum, calcium, magnesium or boron, in an amount of x% (molar% independently of oxygen) relative to silica (100-x%) between 0% and 99%; preferably from 20% to 70%, very preferably between 20% and 50%. The size of these particles is between 10 nm and 50 μm, preferably between 10 nm and 1 μm. According to one embodiment, the reactive additive is a clay such as laponite or sepiolite, a mesoporous silica doped with heteroelements.

According to one embodiment, the reactive additive is a molecule capable of hydrolyzing and then reacting with the strong base of the matrix to form a weak base associated, for example a hydrolysable ester at basic pH, an alkoxide, an amide or an epoxy.

According to one embodiment, the reactive additive is a “Metal Organic Lramework” (MOL) particle based on carboxylate ligands and at least one cation chosen from aluminum, calcium, magnesium, iron, zirconium, titanium capable of dissolving at basic pH, preferably at a pH greater than 10. According to one embodiment, the carboxylate ligand is chosen from oxalate, malonate, succinate, glutarate, phthalate, fumarate or citrate.

According to one embodiment, the reactive additive is a compound comprising at least one ester function hydrolyzable at basic pH, preferably chosen from methyl, ethyl, propyl acetate or butyl acetate.

According to one embodiment, the reactive additive is an alkoxide; preferably a mixed silicon alkoxide or a transition metal alkoxide. According to one embodiment, the reactive additive is a mixed silicon alkoxide comprising at least one Si-C bond, for example methyltrimethoxysilane, (3-glycidyloxypropyl) trimethoxysilane or (3-glycidyloxypropyl) triethoxysilane. According to one embodiment, the reactive additive is an aluminum alkoxide.

According to one embodiment, the reactive additive is a compound comprising at least one amide function, preferably formamide, Ν, Ν-dimethylformamide, oxamide, dicyanodiamide, or propanamine,

According to one embodiment, the reactive additive is a compound comprising at least one epoxy function, preferably (3-glycidyloxypropyl) trimethoxysilane, (3-glycidyloxypropyl) triethoxysilane, diglycidyl ether of bisphenol A (no. CAS 1675-54-3), glycidol, 1,2-epoxybutane and diglycidyl ether of neopentylglycole (CAS no 17557-23-2).

According to one embodiment, the reactive additive is in a range from 5 to 40% by mass relative to the total mass of the composition; preferably from 10 to 35% by mass, more preferably from 15 to 30% by mass.

According to one embodiment, the reactive additive is the zeolite or one of its derivatives, included in a range of 25 to 35% by mass relative to the total mass of the composition; preferably 25 to 30% by mass.

According to one embodiment, the reactive additive is methyltrimethoxysilane, included in a range of 10 to 25% by mass relative to the total mass of the composition; preferably 15 to 20% by mass.

Advantageously, the reactive additive has the effect:

(i) reduce the pH of the composition by consuming hydroxyl ions, thus promoting the condensation of the silicates released when KOH is added to the particles present, the curing of the composition is therefore faster; and / or (ii) to trap potassium to avoid the formation of potassium carbonate hydrates (K2CO3, xfLO) which cause efflorescence, that is to say a growth of white crystals on the surface and / or in the heart material; and / or (iii) increase the mechanical stability of the composition.

Advantageously, the reactive additive produces the effects (i), (ii) and / or (iii) above, and also has the effect:

(iv) modify the rheological properties of the composition; and / or (v) modifying the solubility and / or the hydrophobicity of the final material and / or of the object manufactured from the composition.

In the present invention, the addition of the source of silica, of the water and of the base leads to the formation of a matrix of silicates, which is mixed with a reactive additive as described above.

According to one embodiment, the composition also comprises at least one inert additive, preferably included in the matrix. In one embodiment, the inert additive is added directly within the matrix, before the addition of a reactive additive.

According to one embodiment, the composition comprises an inert additive chosen from the nanoparticles of metallic compounds (gold, platinum), semiconductors (silicon) or dielectric materials (ZrCA T1O2).

According to one embodiment, the composition comprises an inert additive chosen from organic chromophores; preferably from organic chromophores stable at basic pH.

According to one embodiment, the addition of an inert additive to the composition makes it possible to modify the physicochemical properties of the composition such as the color, the density, or the refractive index. According to one embodiment, the addition of an inert additive makes it possible to modify the color of the composition.

According to one embodiment, the additional charge does not include boric acid.

According to one embodiment, the mixing is carried out in one step. According to one embodiment, the mixing is carried out in two stages.

According to one embodiment, the composition comprises the mixture of the source of silica or of one of its precursors, of the base, of water and of the reactive additive to provide the composition of the invention.

According to one embodiment, the composition comprises firstly mixing the source of silica or one of its precursors, the base and water to provide a matrix of silicates; then mixing the matrix with the reactive additive to provide the composition of the invention.

According to one embodiment, the matrix has a dynamic viscosity measured at 20 ° C under constant shear stress at 5 s' of between 10,000 and 10 mPa.s; preferably from 10 5 to 10 7 mPa.s; more preferably from 5.10 5 to 2.10 6 mPa.s.

According to one embodiment, the matrix has a dynamic viscosity measured at 50 ° C. under constant shear stress at 5 s ′ 1 comprised from 100 to 10 6 mPa.s; preferably from 1000 to 10 5 mPa.s; more preferably from 5,000 to 15,000 mPa.s.

According to one embodiment, the matrix has a dynamic viscosity measured at 70 ° C. under constant shear stress at 5 s ′ 1 comprised from 10 to 10,000 mPa.s; preferably from 100 to 1000 mPa.s.

In one embodiment, the pH of the composition is buffered by dissolving the source of silica or one of its precursors as described above, preferably in a range from 10 to 13; more preferably, from 11 to 12.

The present invention also relates to a method of manufacturing a glassy object comprising:

(1) a step of preparing a matrix of silicates, comprising the mixture of a source of silica or one of its precursors, a base and water;

(2) a viscoelastic transition step (or "rheological transition") including a step of forming a composition comprising the silicate matrix of step (1), to form a material; and (3) a polycondensation reaction step, at the end of which a glassy object is obtained.

According to one embodiment, the step of preparing the silicate matrix (1) further comprises the addition of a reactive additive to the silicate matrix. In one embodiment, the matrix and the reactive additive are mixed in a tank.

According to a preferred embodiment, the stage of preparation of the silicate matrix (1) does not include the addition of a reactive additive to the matrix.

According to one embodiment, the viscoelastic transition step (2) comprises the following substeps:

(2-1) Heating of the silicate matrix;

(2-2) Mixing of a reactive additive to the silicate matrix, leading to the production of a composition according to the invention (or "formulation");

(2-3) Shaping of the composition leading to the production of a material; (2-4) Cooling (or "hardening") of the material.

The heating step (2-1) makes it possible to reduce the viscosity of the silicate matrix, thanks to the increase in temperature. At the end of the mixing step (2-2), the viscosity of the composition then increases, generally by a factor of 10, but remains still sufficiently reduced to allow the composition to be shaped during the step (2-3). At the end of the shaping, the material cools quickly which leads to an exponential increase in viscosity: the material thus formed is held, that is to say that it does not collapse under the effect of its own weight.

According to one embodiment, during the mixing step (2-2), the matrix and reactive additive are mixed in a mixer external to the reservoir containing the matrix of silicates.

According to one embodiment, the step of forming the composition (2-3) is carried out at a temperature in a range from 20 ° C to 100 ° C; preferably at a temperature of 30 ° C to 80 ° C; more preferably from 40 to 70 ° C. According to one embodiment, the composition according to the invention is formed by an additive manufacturing technique, by molding or by blowing glass; preferably, the composition is shaped by an additive manufacturing technique; more preferably, by the molten filament deposition method (FDM), by the direct ink writing method (DIW), or by a combination of these methods.

According to one embodiment, the composition is formed by deposition. According to one embodiment, the shaping of the composition provides a thin film. According to one embodiment, the composition is shaped by extrusion. According to one embodiment, the shaping of the composition is carried out by printing. According to one embodiment, the composition of the invention is extruded using a syringe.

According to one embodiment, the composition of the invention is extruded through a needle with a diameter between 100 μm and 5 mm; preferably from 250 µm to 2.5 mm; more preferably from 500 µm to 1.3 mm. According to one embodiment, the composition of the invention is extruded at a pressure of less than 5 bars; preferably less than 2 bars; more preferably at ambient pressure. According to one embodiment, the composition of the invention is extruded at an extrusion speed of 10 to 250 mm / s; preferably about 100 mm / s; within the needle.

In the present invention, the term “setting time” is understood to mean the time necessary to obtain the hardening of the material obtained during step (2-4) of the process. This rapid hardening allows the deposited structure not to sag during shaping, and therefore to obtain a glassy object having the desired shape.

According to one embodiment, the setting time is included in a range from 1 to 120s, preferably from ls to 30s, even more preferably from ls to 5s.

According to one embodiment, the step (3) of polycondensation of the material comprises:

- a rest step in air and at room temperature;

- an annealing step consisting in heating the object between 100 ° C and 300 ° C;

- a chemical bath step in water or in a solvent; and or

- a photo-hardening step.

In one embodiment, the polycondensation step (3) lasts from 1 hour to 5 days, preferably from 1 hour to 3 days.

Advantageously, the composition of the invention makes it possible to control the step of shaping the glassy object at moderate temperatures.

The composition of the invention comprises a matrix (or three-dimensional network) created by bonds between silicates formed in situ by the mixture of water, the source of silica and the base. Before the object is shaped, the increase in temperature destabilizes the weak bonds of the silicate matrix and makes it possible to obtain an adequate viscosity, and therefore an adequate flow, of this matrix. During the implementation of the method, the mixing of a suitable amount of reactive additive with the matrix makes it possible to quickly harden the object resulting from the shaping of the composition of the invention.

The composition according to the invention therefore has the advantage of being able to be subjected to a controllable shaping process (1) thanks to moderate temperatures (rheological transition) and (2) by the addition of a suitable quantity of reactive additive (polycondens ation reaction).

The present invention also relates to a glassy object capable of being obtained by the process of the invention.

According to one embodiment, the glassy object capable of being obtained by the process of the invention is transparent.

According to one embodiment, the glassy object capable of being obtained by the process of the invention is chemically stable. According to one embodiment, the glassy object capable of being obtained by the process of the invention is physically stable.

According to one embodiment, the glassy object capable of being obtained by the process of the invention is not degraded under conditions of extreme temperature, preferably the object is not degraded at temperatures below 500 ° C, preferably less than 600 ° C. According to one embodiment, the glassy object capable of being obtained by the process of the invention is not degraded in the event of immersion in water.

According to one embodiment, the glassy object can be of any shape.

The present invention also relates to a mixing module for the preparation of the composition of the invention comprising: a first compartment comprising a mixture:

- at least one source of silica or one of the precursors;

- at least one base; and

- some water ; in which ;

the base to silica molar ratio is in a range from 0.2 to 1;

the water to silica molar ratio is in a range from 5 to 20;

and a second compartment comprising a reactive additive in a range of 0.1 to 50%, by mass relative to the total mass of the composition contained in the first compartment.

The source of silica or one of its precursors, the base, the reactive or inert additives, their quantities and their respective proportions are as described above.

BRIEF DESCRIPTION OF THE FIGURES

Figure 1 is a ternary diagram silica / potash / water in mass percentage on which is represented a printability range of the compositions according to the invention. The percentage of silica is represented on the right oblique axis, the percentage of potash is represented on the left oblique axis and the percentage of water is represented on the horizontal axis.

Figure 2 is a ternary silica / potash / zeolite diagram in mass percentage. The percentage of silica is represented on the right oblique axis, the percentage of potash is represented on the left oblique axis and the percentage of zeolite is represented on the horizontal axis.

Figure 3 is a ternary silica / potash / silane diagram in mass percentage. The percentage of silica is represented on the right oblique axis, the percentage of potash is represented on the left oblique axis and the percentage of silane is represented on the horizontal axis.

Figure 4 is a histogram illustrating the results of a stability test carried out on samples prepared from compositions according to the invention comprising zeolite as reactive additive.

Figure 5 is a histogram illustrating the results of a stability test carried out on samples prepared from compositions according to the invention comprising methyltrimethoxysilane as reactive additive.

Figure 6 is a graph illustrating the variation of the dynamic viscosity (represented by a decreasing solid line) of an M2 matrix following a ramp of increasing temperatures from 20 ° C to 80 ° C compared to the viscosities measured at temperatures at balance (represented by dots).

Figure 7 is a graph illustrating the variation of the dynamic viscosity (represented by an increasing solid line) of an M2 matrix following a decreasing temperature ramp from 80 ° C to 5 ° C compared to the viscosities measured at temperatures at balance (represented by dots).

Figure 8 is a graph illustrating the variation of the dynamic viscosity of an Ml matrix at 70 ° C, 80 ° C and 85 ° C as a function of the shear gradient varying from ls ' 1 to 100s' 1 .

EXAMPLES

The present invention will be better understood on reading the following examples which illustrate the invention without limitation.

Example 1 Shaping of Glass Filaments in the Absence and then in the Presence of Reactive Additives

The aim of these experiments is to compare the physicochemical properties of glass filaments obtained from compositions with and without reactive additives. The tests were carried out using two types of additives: zeolites for the first series of filaments; methyltrimethoxysilane for a second series.

Compositions without reactive additive

First of all, potassium silicate compositions without additives were produced by mixing colloidal silica in suspension in water (40% by weight, particle diameter of approximately 12 nm, specific surface approximately equal to 220 m 2 / g, Ludox® HS 40), potassium hydroxide (KOH) and water. These experiments made it possible to define the molar ratios and the mass ratios in silica, potash and water to obtain a transparent filament which can be shaped by extrusion. Indeed, these compositions make it possible to define an area where the formation of a gel having a reversible rheological transition is observed at a temperature comprised in a range from 20 ° C. to 90 ° C.

The extrusion is carried out through a syringe with an opening diameter of 250 μm and 1.2 mm at a pressure between 0 and 5 bars.

The compositions without additives which have been tested are described in Tables 1 to 4, according to the quantities of potash used. Among these compositions, only the compositions from A11 to A17 and from A20 to A26 allowed the extrusion of a filament according to the method indicated above. Consequently, it appears from the tests carried out with these compositions that the printable range for potassium silicates is characterized by the following molar ratios:

the base to silica source molar ratio is in the range of 0.3 to 0.5;

the water to silica source molar ratio is in a range from 5 to 11;

The ternary diagram represented in FIG. 1 makes it possible to retranscribe this domain of printability in percentage by mass for all of the compositions tested.

Ref. Amount of silica (g) Amount of water (g) Quantity of KOH (g) Reports molars Water / silica Reports molars base / silica Mass percentage of silica Base mass percentage Al 10 15 2.25 5.01 0.241 36.7 8.3 A2 10 17.5 2.25 5.84 0.241 33.6 7.6 A3 10 20 2.25 6.68 0.241 31.0 7.0 A4 10 22.5 2.25 7.51 0.241 28.8 6.5 AT 5 10 25 2.25 8.34 0.241 26.8 6.0 A6 10 27.5 2.25 9.18 0.241 25.2 5.7 A7 10 30 2.25 10.01 0.241 23.7 5.3 AT 8 10 32.5 2.25 10.85 0.241 22.3 5.0 A9 10 35 2.25 11.68 0.241 21.2 4.8

Table 1: Compositions without additives Al to A9 (2.25 g KOH)

Ref. Amount of silica (g) Quantity of water (g) Quantity of KOH (g) Reports molars Water / silica Reports molars base / silica Mass percentage of silica Base mass percentage A10 10 15 3 5.01 0.321 35.7 10.7 Garlic 10 17.5 3 5.84 0.321 32.8 9.8 AT 12 10 20 3 6.68 0.321 30.3 9.1 A13 10 22.5 3 7.51 0.321 28.2 8.5 A14 10 25 3 8.34 0.321 26.3 7.9 A15 10 27.5 3 9.18 0.321 24.7 7.4 A16 10 30 3 10.01 0.321 23.3 7.0 A17 10 32.5 3 10.85 0.321 22.0 6.6 A18 10 35 3 11.68 0.321 20.8 6.3

Table 2: Compositions without additives A10 to Al8 (3g KOH)

Ref. Amount of silica (g) Amount of water (g) Quantity of KOH (g) Reports molars Water / silic e Reports molars base / silic e Mass percentage of silica Base mass percentage A19 10 15 4.5 5.01 0.482 33.9 15.3 A20 10 17.5 4.5 5.84 0.482 31.3 14.1 A21 10 20 4.5 6.68 0.482 29.0 13.0 A22 10 22.5 4.5 7.51 0.482 27.0 12.2 A23 10 25 4.5 8.34 0.482 25.3 11.4 A24 10 27.5 4.5 9.18 0.482 23.8 10.7 A25 10 30 4.5 10.01 0.482 22.5 10.1 A26 10 32.5 4.5 10.85 0.482 21.3 9.6 A27 10 35 4.5 11.68 0.482 20.2 9.1

Table 3: Compositions without additives A19 to A27 (4.5g KOH)

Ref. Amount of silica (g) Amount of water (g) Quantity of KOH (g) Reports molars Water / silica Reports molars base / silica Mass percentage of silica Base mass percentage A28 10 15 6.75 5.01 0.723 31.5 21.3 A29 10 17.5 6.75 5.84 0.723 29.2 19.7 A30 10 20 6.75 6.68 0.723 27.2 18.4 A31 10 22.5 6.75 7.51 0.723 25.5 17.2 A32 10 25 6.75 8.34 0.723 24.0 16.2 A33 10 27.5 6.75 9.18 0.723 22.6 15.3 A34 10 30 6.75 10.01 0.723 21.4 14.4 A35 10 32.5 6.75 10.85 0.723 20.3 13.7 A36 10 35 6.75 11.68 0.723 19.3 13.0

Table 4: Compositions without additives A28 to A36 (6.75g KOH)

The Applicant has found that the extrusion of compositions in the printable field does not make it possible to obtain glass filaments which are chemically stable, due to the degradation and bleaching of the product, nor physically stable, due to a contraction of the product. finished product upon cooling after extrusion.

Compositions comprising a reactive additive

In order to solve these problems, two new series of experiments were carried out by adding two different reactive additives, one series with zeolite and another series with methyltrimethoxysilane, respectively.

The corresponding compositions are described in Tables 5 and 6. The mass percentage values are indicated dry, since the amount of water can vary significantly depending on the results of the tests without reactive additives. The amount of water added is 5.2 g, but any other water / silica ratio included in the printable range as defined in Example 1 could also be suitable.

Ref. Silica mass (g) Potash mass (g) Additive mass (zeolite, g) Silica (wt%) Based (wt%) Additive (wt%) Z10% 10 4.5 0 69.0 31.0 0.0 Z21% 10 4.5 0.15 68.3 30.7 1.0 Z3 5% 10 4.5 0.77 65.5 29.5 5.0 Z4 10% 10 4.5 1.62 62.0 27.9 10.0 Z5 15% 10 4.5 2.56 58.6 26.4 15.0 Z6 20% 10 4.5 3.7 54.9 24.7 20.3 Z7 25% 10 4.5 4.85 51.7 23.3 25.1 Z8 30% 10 4.5 6.3 48.1 21.6 30.3 Z9 35% 10 4.5 7.83 44.8 20.2 35.1 Z10 40% 10 4.5 9.67 41.4 18.6 40.0 Zll 0% 10 3 0 76.9 23.1 0.0 Z12 10% 10 3 1.45 69.2 20.8 10.0 Z13 20% 10 3 3.25 61.5 18.5 20.0 Z14 30% 10 3 5.58 53.8 16.1 30.0 Z15 40% 10 3 8.7 46.1 13.8 40.1

Table 5: Summary table of the compositions with zeolite as reactive additive.

Last name Silica mass (g) Potash mass (g) Additive mass (silane, g) Silica (wt%) Based (wt%) Additive (wt%) IF 5% 10 4.5 0.77 65.49 29.47 5.04 S2 10% 10 4.5 1.62 61.96 27.88 10.16 S3 15% 10 4.5 2.56 58.48 26.32 15.20 S4 20% 10 4.5 3.7 55.10 24.79 20.11 S5 25% 10 4.5 4.85 51.68 23.26 25.06 S6 30% 10 4.5 6.3 48.26 21.72 30.02 S7 5% 10 3 0.69 73.05 21.91 5.04 S8 10% 10 3 1.5 68.97 20.69 10.34 S9 15% 10 3 2.3 65.36 19.61 15.03 S10 20% 10 3 3.3 61.35 18.40 20.25 SU 25% 10 3 4.34 57.67 17.30 25.03 S12 30% 10 3 5.58 53.82 16.15 30.03

Table 6: Summary table of the compositions comprising methyltrimethoxysilane as reactive additive.

Concerning the series of experiments concerning the compositions with zeolite, the maximum quantity of additive which can be added to the matrix of potassium silicates is

40% by mass percentage, as shown in the ternary diagram in Figure 2.

Beyond this, it is no longer possible to form a filament which has satisfactory mechanical properties.

Regarding the series of experiments concerning the compositions with a silane, methyltrimethoxysilane, the maximum level of additive is this time of 30% by mass. The ternary diagram obtained is shown in Figure 3.

Stability test

All of the samples were then subjected to the following stability test. Tablets of about 10 g (3 cm in diameter, 1 cm thick) were made by molding from each of the compositions mentioned above. These lozenges were then immersed in 50 mL of water for several days. The mass losses of the pellets due to the redissolution of the silicates were measured after 1, 3 and 7 days for each of the samples.

The results for the compositions with zeolites are presented on the histogram of FIG. 4. The complete redissolution of the samples comprising small amounts of zeolite is observed for durations of between a few minutes and 3 days. Conversely, the best chemical resistance is obtained for zeolite levels between 25% and 30%, for which 85% of the initial mass has been preserved. Above 30%, the samples loaded with zeolite begin to crumble after a few days in water.

The presence of methyltrimethoxysilane as a reactive additive greatly strengthens the hydrolysis resistance of the extruded materials as shown in the results presented in Figure 5. With a rate of 15% and 20% by weight of methyltrimethoxysilane, the materials obtained retain more than 90 % of their initial mass, even after 7 days in water.

In conclusion, the composition of the invention is particularly suitable for the manufacture of glassy objects by a 3D printing technique. The implementation of this technique at a temperature between 20 and 90 ° C compared to higher temperature processes, does not alter the properties of the final glass object: the optical quality, which is evaluated by observation visual, is preserved and the product has good stability over time.

Example 2: Shaping by molding and application of a buffer in the absence then in the presence of reactive additives

Molding and tampon application techniques exploiting the viscosity and solidification control of silicate matrices by the quantity of water, the temperature and the addition of reactive additives were tested.

The molds of determined dimensions (length 10 cm; width 10 cm; height 5 cm) were manufactured by 3D printing from polymer materials (PLA - poly (lactic acid)) with circular and crenellated patterns of different sizes (from 0.5 cm to 3 cm). The materials to be shaped are heated for a few minutes in an oven at 70 ° C. and then placed hot in the molds. After the molding step with the different compositions, the hardening of the objects thus formed was compared according to several criteria: drying time, compliance with the imposed shape, shrinkage after drying, cracks or defects observed.

Similarly, stamps (positive or negative shapes) with patterns of different thicknesses (from 0.3 cm to 2 cm) were produced by 3D printing. These pads were then applied to plates of potassium silicates produced by molding with thicknesses between 0.5 cm and 5 cm.

A first series of experiments was carried out with the use of silicate matrices not comprising an active additive, in the absence of post-treatment by bath. This series was then compared to two other series produced with silicate matrices comprising a reactive additive, or after post-treatment by bath.

The compositions tested during the first series are described in Table 7. The results obtained were classified by type of molding or of buffer applied within the

Tables 8 to 10.

Ref. Amount of silica (g) Amount of water (g) Quantity deKOH (g) Reports molars Water / silica Reports molars base / silica Mass percentage of silica Base mass percentage A19 10 15 4.5 5.01 0.482 33.9 15.3 A21 10 20 4.5 6.68 0.482 29.0 13.0 A23 10 25 4.5 8.34 0.482 25.3 11.4 A24 10 27.5 4.5 9.18 0.482 23.8 10.7

Table 7: Compositions used during molding and pad application tests

Ref. Pattern size 0.5 cm 1 cm 2 cm 3cm A19 Drying time 2 min 2 min 4min 7 mins Respect for forms Yes Yes Yes no Withdrawal / / 0.2 cm 0.6cm Defaults / / small bubbles small bubbles A21 Drying time 5 min 7min 10 minutes 12min Respect for forms Yes Yes no no Withdrawal / 0.2cm 0.3cm 0.9cm Defaults / / / small bubbles

A23 Drying time 6min 8min 18min 24min Respect for forms Yes no no no Withdrawal 0.2cm 0.4cm important important Defaults / / / / A24 Drying time lh 2h > 2h > 2h Respect for forms no no no no Withdrawal important important important important Defaults / / / /

Table 8: Results obtained after molding of compositions A19, A21, A23 and A24

Ref. Pattern size 0.3 cm 0.5 cm 1 cm 2cm A19 Drying time 1min 1min 4min 8min Respect for forms Yes Yes no no Withdrawal low 0.2cm important important Defaults / / / small bubbles A21 Drying time 1min 2 min 10 minutes 15min Respect for forms no no no no Withdrawal important important important important Defaults / / / / A23 Drying time 2 min 4min 10 minutes 30min Respect for forms no no no no Withdrawal important important important important Defaults / / / / A24 Drying time 15min 45min l:30 2h Respect for forms no no no no Withdrawal important important important important Defaults / / / /

Table 9: Results obtained after application of positive buffers on plates of compositions A19, A21, A23 and A24

Ref. Pattern size 0.3 cm 0.5 cm 1 cm 2cm A19 Drying time 1min 1min 2 min 4min Respect for forms Yes no no no Withdrawal low 0.2cm important important Defaults / / / small bubbles A21 Drying time 1min 2 min 5 min 8 mins Respect for forms no no no no Withdrawal important important important important Defaults / / / / A23 Drying time 1min 3 mins 7min 15min Respect for forms no no no no Withdrawal important important important important Defaults / / / / A24 Drying time 10 minutes 30min lh l:30 Respect for forms no no no no Withdrawal important important important important Defaults / / / /

Table 10: Results obtained after application of negative buffers on plates of compositions A19, A21, A23 and A24

These results reveal that the compositions not comprising a reactive additive are not very suitable for these shaping techniques. The compositions A23 and A24 do not make it possible to obtain an object either by molding or by application of a buffer, because the imposed shapes are erased after a few hours, even after drying, due to the mobility of the silicates.

The amount of water initially added changes the viscosity and drying time. But it also contributes to the self-repair capacities of these silicate-based materials. Indeed these silicates can migrate more or less easily depending on the water trapped in the network.

Only compositions A19 and A21, with the lowest water percentages, are partially suitable for these shaping techniques, and again only for small dimensions (0.5-1 cm in molding, 0.3-0 , 5 cm in buffer). The formation of small bubbles also weakens the objects obtained with these compositions while reducing its transparency, while the significant shrinkage during drying leads to a deformation of the desired shapes, in particular to a sagging of the patterns for the negative pads.

This first series carried out without reactive additive demonstrates that the problems observed during molding or during the application of buffers make it very difficult to reuse these silicate matrices. The purpose of using reactive additives according to the invention is to limit the negative effects noted during the first series with regard to shaping according to these two methods.

Composition comprising a reactive additive

The second series of experiments with reactive additive was carried out by adding 15% by mass of methyltrimethoxysilane to composition A19. The results obtained are collated in Table 11.

Molding Pattern size 0.5 cm 1 cm 2 cm 3cm A19 + silane Drying time <lmin <lmin 1min 2 min Respect for forms Yes Yes Yes Yes Withdrawal / / 0.1 cm 0.3cm Defaults / / / / Negative buffer Pattern size 0.3 cm 0.5 cm 1 cm 2cm A19 + silane Drying time <lmin <lmin <lmin 1min Respect for forms Yes Yes Yes Yes Withdrawal / / / 0.1 cm Defaults / / / / Positive buffer Pattern size 0.3 cm 0.5 cm 1 cm 2cm A19 + silane Drying time <lmin <lmin 1min 2 min Respect for forms Yes Yes Yes Yes Withdrawal / / / 0.1 cm Defaults / / / /

Table 11: Results obtained after addition of methyltrimethoxysilane (15% by mass) to composition A19

The drying time being greatly reduced, the shapes imposed by molding or by application of buffers (positive or negative) are this time well respected. The absence of significant shrinkage after drying is also a criterion for improving the shaping of these materials.

In conclusion, the compositions according to the invention comprising a silicate matrix and a reactive additive are particularly suitable for shaping techniques such as molding or the application of buffers.

Example 3: Addition of inert additives in order to modulate the color of the objects obtained

These experiments were carried out from the mixture of matrices of potassium silicates or sodium silicates with a colored additive stable in basic medium (ll <pH <12).

A first series of tests was carried out with commercial gold nanoparticles (NanoH®, 5 g / L in water, diameter 5 nm) inserted in a matrix of potassium silicates. A second series was carried out with an organic dye, pyranine, inserted into a matrix of sodium silicates.

Concerning the addition of gold nanoparticles, the following molar ratios were respected:

SiO 2 : 0.48 KOH: 8.75 H 2 O: from 5.10 ' 6 to 5.10' 5 Au

The masses corresponding to these reports are as follows:

SiO 2 : 4g / KOH: 1.8 g / H 2 O: 10.5 g / Au: from 6.6 * 10 ' 5 to 6.6 * 10' 4 g

An evaluation by visual observation shows that the gel obtained remains transparent and has a more or less pronounced purple coloration depending on the amount of gold nanoparticles added. The dispersion of the nanoparticles is homogeneous within the gel, even if a small quantity of violet supernatant may appear on the surface of the gel for the highest concentrations of nanoparticles. These formulations are stable over time, with intact coloring even 2 years after their synthesis. This stability over time makes it possible to classify these stable nanoparticles at basic pH among the inert additives that can easily be used in silicate matrices.

The potential impact of the addition of a reactive additive on the compositions containing gold nanoparticles, was studied by adding to compositions identical to the compositions presented above a certain amount of methyltrimethoxysilane (0.6 g, ie 15% by mass relative to the silica resulting from the compositions before this addition). The formulations without reactive additive were previously heated to 70 ° C to drop their viscosity and thus allow the insertion of the reactive additive.

The results of these additional tests have shown that the addition of reactive additive does not change the shade or the transparency of the samples compared to the series produced without reactive additive.

The second series of samples with pyranine and NaOH as a base was carried out with the following molar ratios:

SiO 2 : 0.7 NaOH: 8.75 H 2 O: from 5.10 -4 to 5.10 -3 Pyranin

The masses corresponding to these reports are as follows:

SiO 2 : 4g / NaOH: 2.62 g / H 2 O: 10.5 g / Pyranin: from 1.8 mg to 18 mg.

Here again, the gel obtained remains transparent and the pyranine gives its fluorescent yellow color to the material with more pronounced homogeneous colors depending on the quantities of pyranine inserted into the matrix.

Additional tests of the compositions comprising 0.6 g of methyltrimethoxysilane have shown that the transparency is well preserved with the same fluorescent yellow hue due to pyranine, and that the presence of the reactive additive therefore has no impact on the 'obtaining coloration.

In conclusion, the composition of the invention is particularly suitable for the manufacture of colored glass objects by a 3D printing technique.

Example 4 Compositions comprising an organic base

In order to characterize the impact of the addition of organic bases on the silicate compositions described in this patent, the following mixtures of bases were tested:

TEAOH ( x %) - KOH (ioo- x %) with TEAOH = tetraethylammonium hydroxide

ΤΡΑΟΗ (χ%) - ΚΟΗ (ΐοο-χ%) with ΤΡΑΟΗ = tetrapropylammonium hydroxide

The physical state (solid, gel, liquid) of the compounds obtained at room temperature (20 ° C) and after drying at 70 ° C is reported for each molar percentage of organic bases in Tables 12 to 15. These results were obtained for a fixed water rate with a Water / Si molar ratio = 9.5 for all these samples.

The presence and extent of the rheological transitions observed for the same cold or hot sample are also reported in these tables. Finally, the physical state after drying at 70 ° C. is indicated in the form of the state of the solid obtained which may be transparent, white, brittle or hard.

% molar for TEAOH-KOH Bases / Si molar ratio (with bases = TEAOH-KOH) 0.3 TEAOH KOH State at 20 ° C Transition rheological After drying at 70 ° C 0% 100% solid gel low crumbly white solid 10% 90% liquid no crumbly white solid 20% 80% liquid no brittle transparent solid 30% 70% liquid no brittle transparent solid 40% 60% liquid no brittle transparent solid 50% 50% liquid no brittle transparent solid 60% 40% pasty then liquid no brittle transparent solid 70% 30% pasty then liquid no brittle transparent solid 80% 20% pasty then liquid no brittle transparent solid 90% 10% liquid no brittle transparent solid 100% 0% liquid no brittle transparent solid

Table 12: Results obtained with a TEAOH-KOH mixture (Bases / Silica = 0.3)

% molar for TEAOH-KOH Bases / Si molar ratio (with bases = TEAOH-KOH) 0.48 TEAOH KOH State at 20 ° C Transition rheological After drying at 70 ° C 0% 100% solid gel important solid transparent 10% 90% honey gel low solid transparent very hard 20% 80% liquid no solid transparent 30% 70% liquid no solid transparent 40% 60% pasty then liquid no solid transparent 50% 50% pasty then liquid no brittle transparent solid 60% 40% pasty then liquid no brittle transparent solid 70% 30% pasty then liquid no brittle transparent solid 80% 20% liquid no brittle transparent solid 90% 10% liquid no brittle transparent solid 100% 0% liquid no brittle transparent solid

Table 13: Results obtained with a TEAOH-KOH mixture (Bases / Silica = 0.48)

% molar for TPAOH-KOH Bases / Si molar ratio (with bases = TPAOH-KOH) 0.3 TPAOH KOH State at 20 ° C Transition rheological After drying at 70 ° C 0% 100% solid gel low crumbly white solid 10% 90% honey gel low crumbly white solid 20% 80% liquid low crumbly white solid 30% 70% liquid no brittle transparent solid 40% 60% liquid no brittle transparent solid 50% 50% pasty then liquid no brittle transparent solid 60% 40% pasty then liquid no brittle transparent solid 70% 30% pasty then liquid no brittle transparent solid 80% 20% pasty then liquid no brittle transparent solid 90% 10% liquid no brittle transparent solid 100% 0% liquid no brittle transparent solid

Table 14: Results obtained with a TPAOH-KOH mixture (Bases / Silica = 0.3)

% molar for TPAOH-KOH Bases / Si molar ratio (with bases = TPAOH-KOH) 0.3 TPAOH KOH State at 20 ° C Transition rheological After drying at 70 ° C 0% 100% solid gel important solid transparent 10% 90% solid gel important solid transparent 20% 80% honey gel low solid transparent 30% 70% pasty then liquid low solid transparent 40% 60% pasty then liquid no solid transparent 50% 50% pasty then liquid no brittle transparent solid 60% 40% pasty then liquid no brittle transparent solid 70% 30% pasty then liquid no brittle transparent solid 80% 20% liquid no brittle transparent solid 90% 10% liquid no brittle transparent solid 100% 0% liquid no brittle transparent solid

Table 15: Results obtained with a TPAOH-KOH mixture (Bases / Silica = 0.3)

Compared to compositions comprising only potash, the organic bases induce a different rheological behavior.

By these tests, the Applicant has established that:

- it is possible to obtain homogeneous mixtures by completely replacing the potash with these organic bases;

the rheological transition is greatly attenuated when the organic base rate increases, which is explained by the fact that potassium (from the postassass) has a denser solvation sphere than the quaternary ammonium ions (from the organic base), which traps water molecules at room temperature before releasing them at higher temperatures; and after drying, the most interesting materials are obtained for a molar ratio of 0.48 in Bases / Si and organic base rates of between 0% and 40%: the solids obtained are then transparent and sufficiently hard to maintain the shape filaments deposited.

In conclusion, following these experiments, it appears that the use of organic bases makes it possible to modulate certain physicochemical properties of the silicate matrices according to the invention.

Example 5 Study of the rheology of potassium silicate matrices

The viscosities of the compositions resulting from the dissolution of the silica particles by the addition of base is vary depending on the temperature and the amount of water added to the silicate matrix.

Table 16 brings together the viscosity values obtained between 20 ° C and 85 ° C for two types of silicate matrix:

- A matrix Ml of composition H2O: 65.5%, S1O2: 23.5%, KOH 10.6% by total mass of the composition; with a water / silica molar ratio of 9.4; and a matrix M2 of composition H2O: 67.4%, S1O2: 22.5%, KOH 10.1% by total mass of the composition; with a water / silica ratio of 10.

Temperatures (° C) 20 30 40 50 60 70 80 85 Viscosity Ml (mPa.s) 17237000 6590430 1722080 455420 139300 27340 16470 11214 Viscosity M2 (mPa.s) 1362400 377050 51210 9510 1912 306 108 81

Table 16: Variation in viscosity as a function of the temperature of the matrices Ml and M2

The difference between these two compositions is very small, since it only corresponds to the 1.5% increase in water over the total mass. However, as shown in Table 16, the viscosities of these two compositions are very different, with a viscosity up to 100 times lower for temperatures between 70 ° C and 85 ° C.

These exponential variations in viscosity as a function of temperature have been measured for equilibrium temperatures. However, for shaping processes such as extrusion, molding or blowing, it is important to have a quick response from the system depending on the temperature variation. An additional study made it possible to show the rapid response of the compositions during increasing or decreasing temperature ramps. The results are presented on the

Figure 6 and Figure 7.

On these graphs, we can see that, at equal temperatures, the viscosities measured at equilibrium (points) and along ramps (lines) are offset by about one minute. This difference corresponds to the time necessary for the propagation of heat both within the material and in the measuring cell of the rheometer. A gap of one minute is small enough that the composition can be used in shaping processes such as extrusion.

It is also important to determine the minimum viscosities that can be achieved while respecting the criteria inherent in the material to be deposited and the corresponding shaping process. In the case of silicate matrices, a temperature close to 100 ° C. would lead to the formation of air bubbles harmful to the material deposited. Figure 8 shows the viscosity of the matrix M1 at 70 ° C, 80 ° C and 85 ° C for different shear gradients from ls ' 1 to 100s' 1 .

Between 70 ° C and 80 ° C the viscosity is divided by 3 (from 300 mPa.s to 100 mPa.s). Between 80 ° C and 85 ° C the viscosity is only reduced by 20% at 80 mPa.s. It therefore seems that a viscosity plateau is reached around 85 ° C. without exceeding the threshold for the formation of air bubbles. On the other hand, the measured viscosities are independent of the shear gradients (between 5s ' 1 and 100s' 1 ). A rheofluidifier comprising at 70 ° C seems to be observed for shear gradients between ls ' 1 and 5s' 1 , but it remains much lower than the exponential variations in viscosity due to temperature.

By determining this rapid rheological transition between 20 ° C and 85 ° C and exponential (between 10 6 and 10 7 mPa.s and 100 mPa.s), the Applicant has established that the compositions studied can:

be extruded through nozzles of sizes between 0.25 mm to 1.2 mm at pressures below 5 bar for extrusion speeds close to 100 mm / s within the nozzle;

harden quickly to form a gel viscous enough to keep the shape imposed during extrusion after depositing the filament on a surface; and allow rapid drying to pass from a gel to a solid object by evaporation alone or by subsequent annealing at moderate temperatures (T <200 ° C) leading to a further exponential increase in viscosity.

Claims (6)

  1. Composition obtained by mixing:
    of a matrix comprising:
    at least one source of silica, chosen from colloidal silica or one of its precursors; at least one base; some water ;
    in which ;
    the base molar ratio on silica source is within a range of 0,
  2. 2 to 1, preferably 0,
  3. 3 to 0.5;
    the water to silica source molar ratio is in a range from 5 to 20, preferably from 5 to 11;
    and at least one reactive additive chosen from:
    (1) a zeolite or one of its derivatives; and (2) a mixed silicon alkoxide or a transition metal alkoxide;
    said reactive additive being in a range of 0.1 to 50%; preferably 5 to 40%; more preferably from 10 to 35%; even more preferably from 15 to 30%, by mass relative to the total mass of the composition.
    The composition of claim 1, wherein the reactive additive is a zeolite having a silica to aluminum molar ratio of more than 0 to 50; preferably from 1 to 5.
    The composition of claim 2, wherein the zeolite is a particle with a diameter of more than 0 to 200 nm; preferably from 1 nm to 100 nm; more preferably, from 10 to 50 nm.
    Composition according to any one of Claims 1 to 3, in which the matrix has a dynamic viscosity measured at 20 ° C under constant shear stress at 5 s' ranging from 10,000 to 10 mPa.s; preferably from 10 to 10 mPa.s; more preferably from 5.10 5 to 2.10 6 mPa.s.
    Method of manufacturing a glassy object comprising:
    a step of shaping the composition according to any one of claims 1 to
  4. 4, at a temperature in a range from 20 ° C to 100 ° C; preferably at a temperature of 30 ° C to 80 ° C; more preferably from 40 to 70 ° C; and a polycondensation reaction step.
    A method of manufacturing a glassy object according to claim 5, further comprising the following preliminary steps:
    (b) a step of preparing a matrix comprising the mixture:
    at least one source of silica chosen from colloidal silica or one of its precursors;
    at least one base; and water;
    in which ;
    the molar ratio base to source of silica is in a range from 0.2 to 1, preferably from 0.3 to 0.5;
    the water to silica source molar ratio is in a range from 5 to 20, preferably from 5 to 11;
    (b) a step of mixing the matrix of step (a) with at least one reactive additive chosen from:
    (1) a zeolite or one of its derivatives; and (2) a mixed silicon alkoxide or a transition metal alkoxide; said reactive additive being in a range of 0.1 to 50%; preferably 5 to 40%; more preferably from 10 to 35%; even more preferably from 15 to 30%, by mass relative to the total mass of the composition.
    A method of manufacturing a glassy object according to claim 5 or according to claim 6, wherein the shaping of the composition is carried out by an additive manufacturing technique, by molding or by blowing glass; preferably, the composition is shaped by an additive manufacturing technique; more preferably, by the molten filament deposition method (FDM), by the direct ink writing method (DIW), or by a combination of these methods.
    8. Glassy object capable of being obtained by the method according to any one of claims 5 to 7.
  5. 5 9. Glassy object according to claim 8, characterized in that the object is transparent.
  6. 10. Mixing module for the preparation of the composition according to any one of claims 1 to 4, comprising: a first compartment comprising a mixture:
    at least one source of silica, chosen from colloidal silica or one of the precursors;
    at least one base; and water ;
    in which ;
    the molar ratio base to source of silica is in a range from 0.2 to 15 1, preferably from 0.3 to 0.5;
    the water to silica source molar ratio is in a range from 5 to 20, preferably from 5 to 11; and a second compartment comprising at least one reactive additive chosen from:
    (1) a zeolite or one of its derivatives; and
    (2) a mixed silicon alkoxide or a transition metal alkoxide;
    said reactive additive being in a range of 0.1 to 50%; preferably 5 to 40%; more preferably from 10 to 35%; even more preferably from 15 to 30%, by mass relative to the total mass of the composition contained in the first compartment.
    1/4
    Silica ifloi
    20%
    40%
    60%
    80%
FR1659132A 2016-09-27 2016-09-27 Composition and method for manufacturing vitreous objects Pending FR3056577A1 (en)

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PCT/FR2017/052613 WO2018060608A1 (en) 2016-09-27 2017-09-27 Composition and method for manufacturing vitreous objects

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3566868A1 (en) * 2018-05-08 2019-11-13 Ernst-Abbe-Hochschule Jena Method for three-dimensional additive manufacturing of a water glass article

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IT1230708B (en) * 1989-02-10 1991-10-29 Enichem Spa Glass-like monoliths constituted by silicon oxide and titanium oxide and process for their preparation.
US20070181043A1 (en) * 2006-01-25 2007-08-09 Heim Warren P Coating suitable for surgical instruments
US9142863B2 (en) * 2009-01-15 2015-09-22 Cornell University Nanoparticle organic hybrid materials (NOHMs) and compositions and uses of NOHMs
US20150307385A1 (en) 2014-04-25 2015-10-29 Massachusetts Institute Of Technology Methods and apparatus for additive manufacturing of glass

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3566868A1 (en) * 2018-05-08 2019-11-13 Ernst-Abbe-Hochschule Jena Method for three-dimensional additive manufacturing of a water glass article

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