FR2528818A1 - Wall or floor tiles for buildings etc. - made from mixt. contg. minerals and binder consisting of aluminosilicate cpds. which undergo polycondensation - Google Patents

Abstract

Tiles are made by the agglomeration of minerals (a), and a geopolymer binder (b). Binder (b) is based on potassium polysialates and/or sodium-potassium polysiloxo-sialates resulting from the polycondensn. of a reaction mixt. with the molar ratios:- M2O/SiO2=0.2-0.48:1; SiO2/Al2O3=3.3-4.5:1, H2O/Al2O3=10-25:1; and M2O/Al2O3=0.8-1.6:1; where M is Na and/or K. After polycondensn. and hardening at below 95 deg.C, the tiles are dried at below 95 deg.C, then immersed in water for 1-48 hours, followed by drying in air. Hard, wear-resistant tiles are obtd.

Description

 The present invention relates to a process for the manufacture of floor or wall coverings obtained by polycondensation of an inorganic alkaline silicoaluminate geopolymer. More specifically, the present invention describes coating materials based on potassium poly (sialate) (K) PS, and or or poly (sialatesiloxo) sodium and or potassium (Na, K) -PSS as described in French patent applications No. 79.22041 and No. 80.18971.

The invention uses an inorganic polycondensation reaction of reaction mixtures based on alkaline silico-aluminates, to manufacture, at low temperature in principle below 1200C, tiles or plates containing at least one inorganic geopolymer of the family of silico-aluminates and different mineral fillers. It constitutes an improvement in the preparation processes described in French patent applications No. 79.22041 / 80.18970 / 80.18971.

The mineral polycondensation reaction is close to that which is at the origin of the synthesis of very particular mineral products: synthetic zeolites or molecular sieves. These products have a very characteristic three-dimensional structure, which is a succession of assembly of TO4 tetrahedra (where T = Si, Al, Ga, P,) forming channels and cavities of regular dimensions. These dimensions are equivalent to those of most organic molecules, which explains the use of these mineral structures to filter organic particles of different dimensions. In addition, these particular structures are used for their ion exchange properties.

They have a certain catalytic action on many organic polymerizations. A large number of patents for the synthesis of these zeolites or molecular sieves describe the manufacturing processes for these particular minerals. A general documentation is constituted by the work of DWBreck: "Zeolite Molecular Sieves" (Interscience Publishers John Wiley & Sons, New York 1974). It is generally a hydrothermal synthesis from a silico-aluminate gel in the presence of strong bases in high concentrations. The reaction is carried out in a closed vessel, at constant pressure and temperature, in the presence of a very large excess of water. In general, the ghois conditions are atmospheric pressure and temperatures between 25cC. and 1250C, and the reaction times are several tens of hours. The raw chemical formula of these synthetic zeolites and molecular sieves is:
M y / n Al Si O, wH 0 y / n 2 (x + y) '2
M being a cation of valence n. Many crystalline products have been obtained by various processes using this hydrothermal synthesis. The objective of these procedures is to obtain products generally in powder form, this crystalline powder possibly being then agglomerated by a binder.

An object of this invention is to describe the use of this hydrothermal synthesis, more precisely of this mineral polycondensation of geopolymer, in order to obtain relatively hard coating materials which can be used in foraging as a coating.
floor or wall.

The terminology used for these mineral geopolymers of three-dimensional structure has been described in the following scientific publications: IUPAC International Symposium on Macromolecules, Stokholm 1976, Topic 111, Applied Polymer Symposia; PACTEC IV, 1979, Society of Plastic Engineers, USA, Preprint page 151. These mineral polymers belong to the class of polysialates of general formula M n - (SiO2) -AIO2-), wH2O in which "z" can be equal to 1 , 2 or 3, "M" is a monovalent cation, "n" is the degree of polymerization. A process for manufacturing a mineral geopolymer corresponding to "z" = 1, ie the general formula
Mn (-Si-O-Al-O-) n, wH2O
OO is described in French patent application n08O.18971, in the form of a potassium K (PS) poly (sialate) in solid solution in a polymeric potassium compound, whose chemical composition expressed in terms of oxides is:
yK2O: A12O3: xSiO2: wH2O in the hydrated form of which "w" is at most equal to 4, "x" is a value between approximately 3.3 and 4.5, "y" is a value taken between 0 , 9 el 1.6 approximately. The (K) -PS obtained has an X-ray diagram close to that of a natural mineral, Kaliophilite KAISiO4.

A manufacturing process corresponding to "z" = 2, ie the general formula
M (-Si-O-Al-O-Si-O-), O
nn 2
OOO is described by French patent application n079.22041 and relating to the synthesis of mineral polymers (Na, K) Poly (sialatesilixo) or
(Na, K) -PSS of general formula
(Na, K) n (-Si-O-Al-O-Si-O-) n, wH2O
OOO 'The molar ratios of the reagents used in the synthesis of (Na, K) -PSS are expressed in Table A:
TABLE A
(Na2O, K20) / SiO2 0.20 to 0.28
SiO2 / A1203 3.5 to 4.5
H2O / A1203 15 to 17.5
(Na2O, K20) / A12O3 0.8 to 1.20
The (Na, K) -PSS obtained have an X-ray diagram close to that of the minerals Analcime, Gismondine, Gmelinite, Phillipsite, as described in Certificate of Addition No. 80.18970.

To prepare the K-Polysialate or (K) -PS, an aqueous reaction mixture of potassium silico-aluminate is used, such that the composition of the reaction mixture expressed by the ratio of the oxides, corresponds to the values indicated in Table B. The experimental value H20 is equal to the water present as a solvent in the mixture, added to the water of chemical composition of the compounds.

TABLE B K2O / SiO2. 0.25 to 0.48
SiO2 / A12O3 .. 3.3 to 4.5
H2O / A1203 ... 10 to 25
K2O / A1203 ... 0.9 to 1.6
The ordinary method of preparing (Na, K) Poly (sialatesiloxo)
(Na, K) -PSS and K-Polysialate, (K) -PS consists in mixing an alumino-silicate oxide in an aqueous solution of alkaline polysilicate, with KOH potash or / and NaOH soda. This aluminosilicate oxide (Si205, Al202) n is prepared from a polyhydroxy-aluminosilicate (Si205, Al2 (OH) 4) n in which the aluminum cation is in the octahedral position and is hexacoordinated.

By dehydroxylation at a temperature between 5500C and 8000C, the polyhydroxy-aluminosilicate is transformed into an extremely reactive aluminosilicate oxide (Si205, Al202) n in which the aluminum cation is tetra-coordinated. The polyhydroxy-aluminosilicates which can serve as raw material are the minerals corresponding to the class of clay minerals at 7 Angstroms, and possessing at least one aluminum cation in the octahedral layer subjacent to the tetrahedral layer of the silicon cation, such as for example the natural minerals: alushité, carnat, china clay, lithomarge, néokaolin, parakaolinite, pholénite, endellite glossecollite, halloysite, milanite, berthiérine, fraigonite, grovenite amesite, chamoisite.

The reaction mixtures, corresponding to Tables A and B, are fluid and behave like a mineral resin having advantageous rheological properties when it is left to mature for approximately at least 1 hour at room temperature, for example 250C. After this maturation, this mineral resin is used as a binder or cement for mineral products of all particle sizes. The resulting mass is then introduced into a mold, then the assembly is hardened, either at room temperature, or at a temperature at most equal to 1200C, preferably between 400C and 950C.

The geopolymers used in the invention for agglomerating mineral materials are based on K-Poly (sialate) K (PS) and (Na, K) -Poly (sialatesiloxo) (Na, K) type silico-aluminates. PSS obtained by foaming (expansion) and polycondensation of a reaction mixture whose molar ratio of oxides corresponds to the values indicated in Table C:
TABLE C
M2O / SiO2 0.20 to 0.48
SiO2 / Al203 3.3 to 4.5
H2O / Al203 1O to 25
M2O / Al203 0.8 to 1.6 in which M2O represents either Na2O, or K2O, or the mixture (.Na20, K20).

Example 1)
860 grams of a mixture containing: HjO: 17.33 moles / K2O: 1.630 moles / SiO2: 4.46 moles / A1203: 1.081 moles are prepared.

A1203 comes from the alumino-silicate oxide (Si205, Al202) n obtained by dehydroxylation of a natural polyhydroxy-aluminosilicate and SiO2 also comes from this alumino-silicate oxide and a potassium silicate solution. K2O comes from potassium silicate and
KOH anhydrous.

The reaction mixture is left to mature for approximately 1 hour at room temperature of 250 ° C. and 400 grams of a natural silico-aluminate with a particle size of 0 to 200 microns are added thereto, and 1,200 grams of zircon sand with a particle size of 0.5 / 1 mm. The mixture is produced in a 200x200 mm tile form, spreading using a vibrating table. The mixture is then allowed to harden.

After polycondensation, the tile is removed from the mold or the impression and then dried at a temperature below 100 "C. The hardening or polycondensation times are obviously a function of the temperature and the heating technique. 25 C, the hardening time is approximately 8 hours; at 500 C 2 hours; at 850 C Oh45 min. Other heating modes can also be used, such as high frequency, microwaves, effect
Joule, the electrical resistance drowned. The reaction mixtures being polyelectrolytes, under these conditions the polycondensation times will be faster.

The order of introduction of the various reagents into the reactive mixtures, according to Table C is important, especially if one wants to give the mineral resin a very long pot life, for example 2 to 4 hours in a workshop. The industrial applications of the invention are thereby greatly facilitated. For this it is necessary to avoid direct contact of the concentrated potassium hydroxide KOH or the concentrated sodium hydroxide NaOH with the aluminosilicate oxide (Si205, Al202) n, To obtain the object of the invention, it is necessary to mask either l aluminosilicate oxide, either KOH or NaOH. The masking of KOH or NaOH takes place by the preparation of a strongly alkaline solution of potassium and / or sodium polysilicate. The aluminosilicate oxide which is thus dissolved therein is then added to this solution. Another method of the invention consists, on the contrary, in masking the aluminosilicate oxide with an alkaline polysilicate solution, then in mixing this mixture with the concentrated solution of KOH or NaOH. The latter method has the advantage of being able to achieve the object of the invention from two mixtures which are stable over time, allowing storage and easy handling. With the mineral resin obtained by allowing the reaction mixture to mature for approximately at least 1 hour at room temperature (250C), the resulting water is softened and has very interesting physical and mechanical properties. even the finest, imprint and mold. This reproduction precision is comparable in quality to that obtained with organic resins commonly used in reproduction and molding, such as epoxy and polyurethane resins.

The quality of the tiles intended for floor covering is mainly measured by the permeability test and the resistance to wear.

In the following, the measurement values refer to the following tests:
Water permeability: A cylindrical PVC water tank with an internal diameter of 195mm and a height of 75mm is placed on the tile. The upper part of this tank is hermetically closed by a welded PVC cover, which is fitted vertically with a graduated glass tube with a diameter of 24mm and 600mm in height. The tightness of the tank was ensured by a silicone sealant seal. At the start of the test, the device is filled with water up to 10 cm from the top of the glass tube. The principle of the method consists in measuring the drop in water level as a function of time. The decrease in the volume of water observed is considered to be the amount of water absorbed by the tile.

Wear resistance: a TABER model 503 abrasimeter is used, the H22, under a load of 1 kg. The tile is fixed on a turntable. The resistance to wear corresponds to the weight loss recorded as a function of the number of turns.

The tiles produced according to Example 1) obtained the following values: permeability :. 220 cm3 of water after 30 hours
abrasion: 4X weight loss after 1000 turns.

Example 2):
These values are appreciably improved when applying to the surface of the tiles of Example 1), waterproofing products such as a solution of sodium Methyl-siliconate applied with a brush:
permeability: after 24h 48h 8 days
15cm3 110cm3
abrasion: weight loss after 500 turns 1.6%
1000 turns 2.0%
The process according to the invention improves the permeability and abrasion results even more significantly.

This improvement is the result of a fortuitous discovery and a treatment whose purpose had originally been entirely different.

The tiles of Example 1) show, after the permeability test, the presence of a white efflorescence which is potassium bicarbonate. This efflorescence is already less significant in the tiles of Example 2) treated with Methyl-siliconate. The removal of this excess potassium cation in the binder can be done by washing with water. It was by carrying out this soaking operation in water that we made the surprising discovery of the improvement in permeability and abrasion.

Example 3):
The tiles, of Example 1) are soaked for 1 day in water, then 'air-dried at room temperature. The permeability and abrasion tests are carried out, the results of which are collated in Table D, with those of Examples 1) and 2).

Table D
Permeability after 24h 30h 48h 8days
Example 1 220cm
2 5cm3 15cm3 110cm3
3 5cm3 10cm3 120cm3
Abrasion:% weight loss after 500 turns 1000 turns
Example 1 4%
2 1.6% 2%
3 0.35% 0.48%
The values for the permeability are equivalent to those obtained in Example 2), and in addition the values of abrasion are 10 times greater than those of Example 1) and 5 times greater than those of Example 2) . Water treatment therefore provides a very significant improvement in the physical characteristics of the material.

The immersion time, i.e. complete rewetting of all the geopolymer material, is obviously a function of the particle size of the mineral filler, the amount of geopolymer binder, the densification (compactness), and the presence of air microbubbles.

This time will be at least 1 hour for a relatively po material.
red, and at most 48 hours for a very compact material.

Claims (1)

SINGLE CLAIM Method for manufacturing floor or wall covering tiles, for building use, obtained by agglomeration of mineral materials and a geopolymer binder based on silico-aluminate type K-Poly (sialate) K-PS and / or (Na, K) -Poly (sialatesiloxo) (Na, K) -PSS, result of the polycondensation of a reaction mixture whose molar ratio of oxides corresponds to the following values: :  M2O / S-iO2 0.20 to 0.48  SiO2 / A1203 3.3 to 4.5  H20 / A1203 10 to 25  M20 / A12O3 0.8 to 1.6 with M2O representing either Na 20, or K2O, or the mixture (Na2O, K2O), characterized in that after the polycondensation and hardening 9 a temperature below 95 "C, and the first drying at a temperature below 950C, these so-called tiles are immersed in water for at least 1 hour, at most 48 hours, then air-dried.