SEALANT CONTAINING A BIO-BASED MINERAL FILLER AND POWDERY COMPOSITION FOR OBTAINING SUCH A SEALANT

Abstract

A putty comprising a mineral filler, a polymeric and / or oligomeric composition, including at least one resin and / or monomers and / or oligomers, and possibly a polymerization initiator, a liquid which may be water, and wherein said mineral filler consists of at least 30%, preferably 40%, most preferably 50%, of calcium carbonate obtained, with a purity of at least 80%, preferably at least 85%, preferably at least 90%, and even more preferably at least 95%, from eggshells. A powder composition for the preparation of such a putty. Figure for the abstract: [Fig 1]

Description

Title of the invention: MASTIC COMPRISING A BIOSOURCED MINERAL FILLER AND POWDERY COMPOSITION TO OBTAIN SUCH A MASTIC TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to preparations which can be used to fill cavities, holes or cracks in solid materials, in particular in a wall, a floor, a stone, ceramic or wooden product. It relates more particularly to sealants comprising a mineral filler. The invention relates more particularly to a sealant comprising a mineral filler partly consisting of biosourced calcium carbonate. The present invention also relates to a powdery composition for the preparation of such a sealant. STATE OF THE ART

[0002] The term mastic is used to designate a hardenable pasty composition obtained by mixing different synthetic or natural substances which give it certain mechanical qualities necessary for filling a cavity, for making joints between several elements or for caulking, repairing, masking, gluing or sealing.

[0003] A sealant may be in the form of a ready-to-use pasty composition, sometimes called a single-component sealant because it does not require any mixing operation prior to use. A sealant may also be supplied to the user in the form of a powdery composition which must be mixed with at least one other component, generally water, to form the ready-to-use sealant. A sealant in this second form may be called two-component or multi-component.

[0004] The prior art knows a great diversity of mastics whose compositions vary to fulfill their particular function. Filling mastics usually comprise as first element, in mass proportion, a mineral filler of calcium carbonate forming the body of the mastic and the proportion of which determines the consistency and viscosity of the mastic.

[0005] The calcium carbonate usually used in putty compositions is of mineral origin, taken from limestone or marble quarries. Calcium carbonate of mineral origin is preferred for its abundant availability, low cost and simple crystalline structure comprising mainly two structures, aragonite and calcite. Conversely, calcium carbonates of organic origin have more complex and varied structures, and the supply of bio-sourced calcium carbonate can be difficult.

[0006] In all cases, the precise origin of the calcium carbonate, its purity, its crystallinity, its granulometry, its granular morphology, its wettability are among the main parameters which influence the properties which it is likely to confer on the composition in which it is incorporated, and, ultimately, on the properties of the finished product obtained from this composition.

[0007] In addition to the mineral filler, a putty composition usually includes a functional filler whose main role is to provide resistance to cracking and shrinkage. The functional filler can have very varied forms and natures, for example fibers such as plant fibers (cellulose, flax, hemp, etc.), synthetic fibers (glass, composite, plastics, etc.), but also beads or micro-beads or finally other mineral materials such as talc, mica, kaolin, among others.

[0008] Other elements entering into the composition of a mastic include a resin whose function is to ensure resistance to shrinkage and adhesion to the support, a solvent and a thickener whose proportions make it possible to adjust the rheology of the mastic and one or more additives. OBJECTS OF THE INVENTION

[0009] The present invention aims to provide a new mastic composition and in particular mastic whose composition comprises elements of biosourced origin.

[0010] The concept of biosourced carbon content, within the meaning of the present invention, as well as the method for its determination, is defined in standard NF ISO 16640 “Biosourced products - Biosourced carbon content - Determination of biosourced carbon content by the radiocarbon method”, published on April 15, 2017.

[0011] This method uses as a marker of the "biosourced" characteristic the isotopic ratio 14C / 12C which is different in a material of mineral origin and in a material of biological origin. Thus, the carbon contained in the biosourced calcium carbonate, in particular in the calcium carbonate from eggshells, is a carbon of biological origin and not of mineral origin, even if the hen needs to absorb calcium carbonate of mineral origin to produce eggs.

[0012] To this end, according to a first object, the present invention relates to a mastic comprising: - a mineral filler, - a polymeric and / or oligomeric composition, comprising at least one resin and / or monomers and / or oligomers, and possibly a polymerization initiator, - optionally a liquid which can be water, - optionally functional additives, and in which said mineral filler consists of at least 30%, preferably 40%, very preferably 50% carbonate of calcium obtained, with a purity of at least 80%, preferably at least 85%, preferably at least 90%, and even more preferably at least 95%, from eggshells.

[0013] Said mineral filler may comprise other things than calcium carbonate, for example calcium sulfate. Its general function is to give the putty its pasty consistency for its intended application; the viscosity of a putty can be adjusted in a simple manner by adding liquid.

[0014] Said polymeric and / or oligomeric composition forms a solid resin after drying; it gives the mastic, after drying, its hardness, its resistance to cracking and shrinkage, as well as its adhesion to the support.

[0015] A first advantage of the mastic which is the subject of the invention is that it presents a recovery route for calcium carbonate extracted from eggshells, which is an available by-product for which few uses are known. Another advantage is that the mastic which is the subject of the invention has a significant content, preferably a majority, of carbon of biosourced origin, the obtaining of which does not require the exhaustion of a fossil resource, unlike mastic comprising mainly calcium carbonate extracted from quarries.

[0016] According to the invention, the mineral filler consists of at least 30%, preferably 40%, very preferably 50% calcium carbonate obtained, with a purity of at least 80%, preferably at least 85%, preferably at least 90%, and even more preferably at least 95%, from egg shells.

[0017] In embodiments, the biosourced carbon content in the mastic is greater than 50%, preferably greater than 60%, very preferably greater than 70%.

[0018] To achieve these biosourced carbon contents, the majority of the mineral filler must come from eggshells transformed into powder. Advantageously, at least some of the various functional agents, which can be included in the composition of a putty, are also biosourced, such as, for example, a cellulosic functional filler derived from natural cellulosic fibers.

[0019] In embodiments, the mastic comprises, in mass percentages: - between 60% and 75% of said mineral charge, - between 10% and 20% of said polymeric and / or oligomeric composition, this percentage relating to a dry extract in the case where said polymeric and / or oligomeric composition is introduced in the form of an emulsion, - of the liquid quantum satis.

[0020] Such a sealant has a viscosity particularly suitable for filling cavities, holes and cracks; this viscosity can be adjusted by fine control of the component content.

[0021] In embodiments, the sealant comprises at least one cellulosic functional filler. It increases resistance to cracking and shrinkage.

[0022] Thanks to these provisions, the putty is particularly suitable for filling cavities formed in the wood.

[0023] In particular embodiments, the mastic comprises, in mass percentages: - between 50% and 72%, preferably between 60% and 72%, very preferably between 68% and 72% of said mineral charge, - between 1% and 5% of said cellulosic functional charge, - between 5% and 20% of said polymeric and / or oligomeric composition, this percentage relating to a dry extract in the case where said polymeric and / or oligomeric composition is introduced in the form of an emulsion, - quantum satis liquid, this liquid being advantageously water.

[0024] This formulation has an optimal viscosity for “ready to use” use.

[0025] In embodiments, said cellulosic functional filler is predominantly strictly of bio-sourced origin. Advantageously, said cellulosic functional filler is chosen from functional cellulose, cellulose fiber, wood flour, hemp fiber, hemp residue, lignin powder, wood residue, silvery coffee film.

[0026] Thanks to these provisions, the content of carbon of biosourced origin in the mastic obtained is greater. According to an advantageous embodiment, the cellulosic functional filler is mainly made up of silvery film from coffee.

[0027] In embodiments, the polymeric and / or oligomeric composition is an acrylic or styrene-acrylic resin with a minimum film formation temperature of between 0°C and 35°C.

[0028] In embodiments, the sealant comprises one or more of the following functional additives: - An anti-foaming agent, - A dispersing agent, - A biocidal agent, - A thickening agent, - An antioxidant agent.

[0029] Thanks to these provisions, certain characteristics of the mastic can be controlled, in order to facilitate its manufacture or use.

[0030] According to a second aspect, the invention relates to a powdery composition for the preparation of a mastic as described above, comprising, expressed in mass percentages: - a mineral filler, which consists of at least 30%, preferably 40%, very preferably 50% calcium carbonate obtained, with a purity of at least 80%, preferably at least 85%, preferably at least 90%, and even more preferably at least 95%, from eggshells. - optionally a cellulosic functional filler.

[0031] In embodiments, the powdery composition further comprises one or more of the following constituents: - A wetting agent, - An anti-foaming agent, - A dispersing agent, - A biocidal agent, - A thickening agent, - An antioxidant agent.

[0032] In embodiments applicable to both the putty and the powdery composition, said mineral filler has a grain size D50 of between 5 pm and 70 pm, preferably of between 20 pm and 55 pm, preferably of between 25 pm and 50 pm, and even more preferably of between 35 pm and 45 pm.

[0033] In certain embodiments, the powdery composition has a biosourced carbon content greater than 60%, preferably greater than 70%, and even more preferably greater than 80%.

[0034] Certain aims, advantages and particular characteristics of the powdery composition which is the subject of the present invention being similar to those of the mastic which is the subject of the present invention, they are not recalled here. BRIEF DESCRIPTION OF THE FIGURES

[0035] Other advantages, aims and particular characteristics of the invention will emerge from the following non-limiting description of at least one particular embodiment of the mastic and the powdery composition which are the subject of the present invention, with reference to the appended drawings, in which:

[0036] [Fig.l] represents the viscosity curves as a function of the shear rate illustrating the rheological profiles of two mastics made from distinct sources of calcium carbonate: a so-called “biosourced” mastic comprising a calcium carbonate extracted from eggshell powder and a so-called “control” mastic comprising a calcium carbonate of mineral origin,

[0037] [Fig.2] represents the hardness measurements, expressed in Shore units, of the putty biosourced and control putty presented in [Fig.l],

[0038] [Fig.3] represents the viscosity curves as a function of the shear rate illustrating the rheological profiles of two sealants, including a sealant comprising calcium carbonate from a mineral source and a particular embodiment of the sealant composition which is the subject of the present application, which comprises calcium carbonate extracted from eggshell powder.

[0039] [Fig.4] represents viscosity curves as a function of shear rate illustrating the rheological profiles of two mastics made with two extracts of chicken eggshell powder, respectively 90 and 96% pure calcium carbonate. DETAILED DESCRIPTION OF THE INVENTION

[0040] The present description is given without limitation, each characteristic of an embodiment being able to be combined with any other characteristic of any other embodiment in an advantageous manner. Unless otherwise stated, all percentage values ​​relate to mass percentages.

[0041] Rheological impact of using eggshell calcium carbonate

[0042] The inventors evaluated the rheological consequences of using calcium carbonate from eggshell in a single-component sealant.

[0043] To do this, two identical mastic compositions were prepared except for the mineral filler used. The formulation of the control mastic, comprising a mineral filler from a quarry, and the formulation of a so-called “bio-sourced mastic”, comprising a mineral filler from eggshell powder, are detailed in Table 1 below.

[0044] [Tables 1] Control putty (percentages by mass) Biosourced putty (percentages by mass) Calcium carbonate from quarries 68% 0% Calcium carbonate from eggshell powder 0% 68% Arbocel™ C750 1.65% 1.65% Vinavil™ L2160 15% 15% Airtap™ 834 1.35% 1.35% Ecodis™ P50 2% 2% Water 11% 11% Preventol™ BIT 10 0.4% 0.4% Texipol™ 63-202 0.6% 0.6%

[0045] The products used in the composition of the control mastic and the bio-sourced mastic presented above will be better understood by reading the description of the single-component sealant according to formulation 1, which includes the same products as the bio-sourced sealant.

[0046] It is noted that the calcium carbonate from eggshell powder used in the composition presented in Table 1 has a calcium carbonate purity estimated at 96% according to the method for determining the biosourced carbon content by the radiocarbon method (standard NF EN 16640:2017).

[0047] The viscosity values ​​for the control sealant and the bio-sourced sealant are measured using a Brookfield™ viscometer (module 7) at different shear rates, at 20°C. The viscosity values, expressed in milliPascale per second (mPas), as a function of the shear rate, expressed in revolutions per minute, are presented in [Fig.l] and linked together in series by trend curves.

[0048] The inventors observed, as illustrated in [Fig.l], a significant difference in the viscosity values ​​of the control sealant and the bio-sourced sealant at low shear rate, the bio-sourced sealant being very thick and dry. On the contrary, with a higher shear rate, the control sealant and the bio-sourced sealant have similar viscosity values ​​and applicability with a fairly similar spatula.

[0049] The inventors have thus observed that calcium carbonate from eggshells has a different, and more precisely greater, oil uptake in the powdered state than a calcium carbonate powder of mineral origin, with a comparable particle size.

[0050] In addition, hardness measurements of the control sealant and the bio-sourced sealant were carried out using an identical measurement protocol. The results of these measurements are presented in [Fig.2]. The results obtained highlight a higher hardness of the bio-sourced sealant compared to the control sealant. Too high a hardness, such as that measured for the bio-sourced sealant, indicates that the appearance of cracks during drying after application of the sealant will be more frequent.

[0051] The inventors thus observed that the mechanical properties of the biosourced mastic are considerably modified, compared to the control mastic, probably due to the presence of organic molecules such as proteins very rich in weak bonds.

[0052] The results obtained by the inventors indicate that it is not possible to simply substitute the mineral filler from quarries with a mineral filler from eggshell powder without degrading the rheological characteristics of the mastic.

[0053] Generally speaking, the viscosity of the product can be adjusted by appropriately choosing the nature of the polymeric and / or oligomeric composition, the proportion and composition of the mineral filler, the nature and proportion of the functional additives (including thickening agent), and liquid content.

[0054] In practice, to adjust the viscosity of a prepared mastic, liquid, thickening agent or mineral filler can be added.

[0055] In the following description, putty formulations created by the inventors and aimed at overcoming the rheological defects introduced by the use of a calcium carbonate derived from eggshell powder are presented. Mineral filler from eggshell powder

[0056] The mastic and the powdery composition according to the invention comprises a mineral filler consisting of at least 30%, preferably 40%, very preferably 50% calcium carbonate obtained from eggshell powder. Preferably this proportion is increased to 80%, very preferably 90%, and it can reach 100%. The eggshells typically come from chicken egg breaking workshops.

[0057] A chicken eggshell is typically composed of 95% calcium carbonate, 3.5% membrane materials (mainly proteins), and 1.5% water. The composition of the eggshell makes it suitable as a source of calcium carbonate, provided that the eggshell is subjected to a purification process that removes at least some of the impurities, which include, in particular, membrane residues, clays, and silicates.

[0058] In the context of the present application, the calcium carbonate used in the compositions detailed below was obtained from the company Circul'Egg SAS.

[0059] The analysis of a sample according to the method for determining the biosourced carbon content by the radiocarbon method (standard NF EN 16640:2017) in the calcium carbonate from eggshell marketed by the company Circul'Egg has among others determined that said calcium carbonate has a carbon 14 content of 98% ±2%, which makes it possible to confirm the biosourced nature of this raw material.

[0060] Purity of calcium carbonate from eggshells

[0061] According to the invention, the mineral filler comprises calcium carbonate obtained, with a purity of at least 80%, preferably with a purity of at least 85%, preferably at least 90%, and even more preferably at least 95%, from egg shells.

[0062] For example, the mineral filler consists of at least 30% calcium carbonate obtained with a purity of 90%. For example, the mineral filler consists of at least 30% calcium carbonate obtained with a purity of 96%.

[0063] The rheological profile of two particular examples of the mastic which is the subject of the invention, which vary from one another only in that they comprise calcium carbonates of different purity grades, respectively 90% and 96%, has been established. The values Viscosity values ​​for these two sealants are measured using a Brookfield™ viscometer (module 7) at different shear rates, at 20°C. The viscosity values, expressed in milli-Pascal per second (mPa.s), as a function of the shear rate, expressed in revolutions per minute, are presented in [Fig.4] and linked together in series by trend curves.

[0064] The inventors have found that the flow threshold value, i.e. the shear stress from which the mastic composition flows, is lower for a mastic composition comprising a mineral filler of lower purity of calcium carbonate.

[0065] A purity of the calcium carbonate from eggshell greater than a predetermined value is therefore desirable so as to increase the flow threshold and thus facilitate the application of the sealant and its hold after application. In addition, a flow value that is too low must be avoided in order to ensure the stability of the sealant in the pot. Indeed, below a certain threshold the sealant in the pot can become phase-shifted.

[0066] Thus, the mastic which is the subject of the invention comprises a mineral filler of calcium carbonate from eggshell with a purity greater than or equal to 80%, preferably 85%, preferably 90%, and even more preferably 95%. Granulometry of the mineral filler

[0067] The particle size measurement Dv50 here represents the size of the particles of a sample for which 50% of the volume of the sample has a finer particle size. Similarly, the particle size measurements Dvio and Dv90 represent the size of the particles of a sample for which, respectively, 10% of the volume of the sample and 90% of the volume of the sample has a finer particle size.

[0068] In embodiments, the mineral filler used in the mastic and the powdery composition which are the subject of the invention is formed from calcium carbonate from eggshells having a grain size Dv50 of between 5 pm and 70 pm, preferably of between 20 pm and 55 pm, preferably of between 25 pm and 50 pm, and even more preferably of between 35 pm and 45 pm.

[0069] These provisions make it possible to obtain a putty with a rheology that is neither too fluid nor too pasty. The use of a mineral filler formed from calcium carbonate with a grain size that is too coarse would have the effect of forming a composition that is too liquid with too little oil uptake, likely to flow outside the hole to be filled before solidifying in place. Conversely, a grain size that is too fine would have the effect of forming a composition that is too pasty with too much oil uptake, difficult to handle and force into the gaps to be filled by the putty.

[0070] In embodiments, the mineral filler used in the mastic and the powdery composition which are the subject of the invention is formed from calcium carbonate derived from eggshells present: - a grain size Dvio less than or equal to 10 pm, preferably less than or equal to 5 pm, - a Dv50 grain size between 10 pm and 30 pm, preferably between 15 pm and 25 pm and - a grain size Dv90 greater than or equal to 40 pm, preferably greater than or equal to 45 pm.

[0071] In other words, the particle size of the mineral filler formed from calcium carbonate from eggshells has an inhomogeneous particle size with large grains (of the order of 90 μm or greater) and small grains (of the order of 10 μm or less). A putty comprising a mineral filler which has these characteristics cracks less during drying after application to a hole to be filled. The less frequent appearance of cracks or their smaller size is probably explained by improved compaction properties of the mineral filler, which limit the shrinkage of the putty during drying.

[0072] It is emphasized that the mineral filler formed from purified calcium carbonate from crushed eggshells directly has an inhomogeneous particle size, which presents another advantage of the use of such a mineral filler for the mastic and the powdery composition which are the subject of the invention. Polymeric and / or oligomeric composition

[0073] The mastic and the powdery composition which are the subject of the invention comprise a polymeric and / or oligomeric composition comprising at least one resin and / or monomers and / or oligomers.

[0074] The role of said polymeric and / or oligomeric composition is to contribute to the hardness of the mastic, to its resistance to cracking and shrinkage, and to enable good adhesion of the mastic to a support.

[0075] In embodiments, a powdery composition for the preparation of a mastic which is the subject of the invention comprises a polymeric and / or oligomeric composition, comprising at least one resin and / or monomers and / or oligomers, chosen from: Vinavil™ 5406, 5515 or 5526 from the company Vinavil, DA-1100 or DA-1400 from the company Dairen Chemical Corporation, or Elotex™ FL 2200 or FL2280 from the company Celanese.

[0076] In embodiments, a single-component sealant which is the subject of the invention comprises a polymeric and / or oligomeric composition, comprising at least one resin and / or monomers and / or oligomers, chosen from emulsion resins: Acronal™ S790 or Acronal™ A754 from BASF, Vinamul™ 3171 or Vinamul™ 3265 from Celanese, Alberdingk™ SC 4400 from Al-berdingk, Mowilth™ LDM 6911 from Celanese or Carboset™ CA 600 of the Lubrizol company.

[0077] In embodiments, the mastic comprises between 5% and 20% of said polymeric and / or oligomeric composition, this percentage relating to a dry extract in the case where said polymeric and / or oligomeric composition is introduced in the form of an emulsion.

[0078] The presence of the polymeric and / or oligomeric composition comprising at least one resin in the mastic composition has the effect of improving the performance of the mastic, as detailed above. It is noted that below a percentage by mass, for example less than 5%, of polymeric and / or oligomeric composition comprising at least one resin in the mastic, the latter may have a sandy or inhomogeneous consistency. It is noted that beyond a certain percentage by mass, for example greater than 20%, of polymeric and / or oligomeric composition comprising at least one resin in the mastic, the latter may exhibit too much shrinkage upon drying.

[0079] The inventors have found that the use of a mineral filler of calcium carbonate from eggshells instead of a mineral filler from quarries leads to a reduction in mechanical and filling performance, i.e. the appearance of cracks and excessive viscosity at low shear speed.

[0080] The use of a polymeric and / or oligomeric composition comprising an acrylic or styrene-acrylic resin with a minimum film formation temperature, also called TMFF, of glass transition between 0°C and 35°C makes it possible to overcome these defects.

[0081] For example, the polymeric and / or oligomeric composition is an acrylic or styrene-acrylic resin with a minimum film formation temperature, also called TMFF, of between 0°C and 35°C. For example, the polymeric and / or oligomeric composition is chosen from the binders Texicryl™ 13-023 or 13-073, Carbosel™ 720RC, or Mowilith™ 6116.

[0082] In another embodiment, the polymeric and / or oligomeric composition is a polyvinyl resin. Indeed, the inventors have found that the use of such a resin makes it possible to overcome, at least in part, the defects linked to the use of a mineral filler of calcium carbonate derived from eggshell. Single-component water-based sealant

[0083] A single-component mastic is a pasty composition which has the mechanical qualities necessary for filling a cavity, for making joints between several elements or for caulking, repairing, masking, gluing or sealing and which is ready to use, i.e. which does not require any mixing operation prior to use.

[0084] Two particular examples of single-component sealant according to the invention: formulation 1 and formulation 2. Formulation 1

[0085] According to a first particular example of a single-component aqueous-phase sealant, the sealant is a composition, hereinafter referred to as “formulation 1”, comprising the elements listed in Table 2:

[0086] [Tables2] Component Putty according to formulation 1 (mass percentages) Calcium carbonate from eggshell powder 68% Arbocel™ C750 1.65% Vinavil™ L2160 15% Airtap™ 834 1.35% Ecodis™ P50 2% Water 10.8% Preventol™ BIT 10 0.4% Texipol™ 63-202 0.8%

[0087] Arbocel™ C750 is a cellulose-based functional filler. Vinavil™ L2160 is an aqueous dispersion of polyvinyl acetate. Airtap™ 834 is an anti-foaming agent comprising a mixture of ethers, paraffin hydrocarbons and polyalcoxiesters. Ecodis™ P50 is a dispersant additive. Preventol™ BIT 10 is a biocide. Texipol™6 3-202 is a thickener.

[0088] The dimensional stability of formulation 1 and more precisely its resistance to cracking was estimated by filling holes of different depths, 1 millimeter (mm), 5 mm, 10 mm, 15 mm and 20 mm. Good resistance to cracking without having a very significant cavity effect was observed at least up to 10 mm. A crack was however observed on the filled holes of 15 mm and 20 mm.

[0089] The rheological profiles of the sealant according to formulation 1 were established by measuring its viscosity using a Brookfield™ viscometer (module 7) at different shear rates. The viscosity values, expressed in millipascals per second (mPas), as a function of the shear rate, expressed in revolutions per minute for the sealant according to formulation 1 and for the control sealant are presented in [Fig.3] and linked together in series by trend curves.

[0090] On the graph in [Fig.3], we see a profile very similar to the control putty with a high flow threshold to avoid rapid phase separation but with a very rapid viscosity drop allowing immediate applicability.

[0091] Formulation 2

[0092] According to a second particular example of a single-component aqueous-phase sealant, the sealant is a composition comprising the elements listed in Table 3:

[0093] [Tables3] Sealant component according to formulation 2 (mass percentages) Calcium carbonate from eggshell powder 64% Glassbubble™ K20 10% Vinavil™ L2160 21% Airtap™ 834 1.35% Water 10.8% Preventol™ BIT 10 0.4% Texipol™ 63-202 0.8%

[0094] Formulation 2 of single-component sealant differs from formulation 1 in particular in that it comprises the product Glassbubble™ K20 which comprises hollow glass microbeads which contribute to better dimensional stability, i.e. a better capacity of the sealant to fill larger holes without forming cracks.

[0095] Powdery composition for the preparation of a putty

[0096] A sealant may be supplied to the user in the form of a powdery composition which will need to be mixed with at least one other component, generally water, to form the ready-to-use sealant. A sealant in this second form may be called two-component or multi-component.

[0097] Two particular examples of two-component sealant according to the invention are described below: formulation 3 and formulation 4.

[0098] Formulation 3

[0099] According to a first particular example of a powdery composition for the preparation of a mastic according to the invention, said composition comprises the elements listed in Table 4:

[0100] [Tables4] Component Powder composition according to formulation 3 (mass percentages) Calcium carbonate from eggshell powder 93.5% Vinavil™ 5515 6.3% Acticide™ MBP 0.8%

[0101] The product Vinavil™ L2160 is a redispersible terpolymer powder. The product Acticide™ MBP is a biocide.

[0102] A putty is obtained by dispersing in a mixture 75% by mass of powder composition according to formulation 3 with 25% by mass of water.

[0103] The putty obtained by mixing the powder composition according to formulation 3 has a long open time, good dispersibility of the powder with water and a repair depth of 5 mm. The term open time refers to the subjective duration of time during which the putty obtained by mixing the powder composition with water is usable. Once the powder composition is mixed with water, the viscosity of the putty obtained increases over time until the product becomes unusable.

[0104] The mechanical and chemical performances of this putty were compared with the performances of a putty obtained by mixing with water a powdery composition comprising a calcium carbonate marketed under the name Mikhart™ 40 by the company Provençale SA. Mikhart™ 40 is a mineral calcium carbonate, i.e. derived from quarrying. The comparative results concerning these two putties are presented in the table below.

[0105] [Tables5] Open time Putty obtained by mixing water with the powder composition according to formulation 3 Putty obtained by mixing water with a powder composition based on Mikhart™40 8h in closed container 8h in closed container Dispersability of the powder Very easy to mix Very easy to mix Filling From 1 mm to 10 mm No cracking No cracking 15 mm Slight cracking No cracking 20 mm Significant cracking Slight cracking Hardness (shore D) 52 57

[0106] The more rapid appearance of cracking is observed for the putty obtained from the powdery composition according to formulation 3 (from 15 millimeters). However, it is noted that a putty obtained from the powdery composition according to formulation 3 is particularly suitable for filling cavities of 1 to 10 millimeters.

[0107] Formulation 4

[0108] According to a second particular example, the powdery composition for the preparation of a mastic according to the invention comprises:

[0109] [Tableauxô] Component Powder composition according to formulation 4 (mass percentages) Calcium carbonate from eggshell powder 93.5% Vinavil™ 5406P 6.3% Culminai™ 15 00 PFR 0.6% Acticide™ MBP 0.8%

[0110] Vinavil™ 5406P is a vinyl acetate / vinyl versatate / acrylic ester in a polyvinyl alcohol colloid in redispersible powder form. Culminai™ 15 00 PFR is a water-soluble, non-ionic cellulose ether.

[0111] A putty is obtained by dispersing in a mixture 75% by mass of powder composition according to formulation 4 with 25% by mass of water. UV-curable sealant

[0112] In a particular embodiment, the sealant is crosslinkable under UV radiation; it does not dry in air. In this case, a photoinitiator must be added to the polymeric and / or oligomeric composition; the latter must be selected so as to allow photo-induced crosslinking. The sealant crosslinkable under UV radiation is typically a single-component sealant. Its content of polymeric and / or oligomeric composition may be greater than 20%.

[0113] In an advantageous embodiment, such a composition is essentially an oligomeric composition; it preferably does not contain water. Its viscosity can be adjusted, as needed, by the addition of liquid oligomers.

[0114] A particular example of a photo-crosslinkable single-component sealant according to the invention is described below.

[0115] Formulations Component Sealant according to formulation 5 (mass percentages) Ebecryl™ 80 62.4% Dispersant™ DS 10 2.7% Byk™ 066 2% Kaolin 18.9% Calcium carbonate from eggshell powder 10.9% Doublecure™ 1173 2.6%

[0116] Calcium carbonate from eggshell powder has a purity grade of 90%. Ebecryl™ 80 is a low viscosity, multifunctional polyether acrylic oligomer modified with amines, Byk™ 066 is a silicone-based antifoam, Doublecure™ 1173 is a photoinitiator used to initiate the photopolymerization of chemically unsaturated prepolymers. Finally, Kaolin is a white clay composed mainly of kaolinite

[0117] The UV-crosslinkable sealant according to formulation 5 was compared with an identical formulation but which contains as mineral filler a calcium carbonate from the exploitation of limestone in a quarry (Durcal™ 5 product), at an identical rate of 10.9%. The two sealants compared have a very similar profile with a high flow threshold to avoid rapid phase separation but with a very rapid drop in viscosity allowing easier application.

Claims

Claims

1. Mastic comprising: - a mineral filler, - a polymeric and / or oligomeric composition, comprising at least one resin and / or monomers and / or oligomers, and possibly a polymerization initiator, - optionally a liquid which may be water, - optionally functional additives, characterized in that said mineral filler consists of at least 30%, preferably 40%, very preferably 50% calcium carbonate obtained, with a purity of at least 80%, preferably at least 85%, preferably at least 90%, and even more preferably at least 95%, from eggshells.

2. Mastic according to claim 1, in which the calcium carbonate mineral filler has a grain size Dv50 of between 5 pm and 70 pm, preferably of between 20 pm and 55 pm, preferably of between 25 pm and 50 pm, and even more preferably of between 35 pm and 45 pm.

3. Mastic according to one of claims 1 or 2, in which the mineral filler is formed from calcium carbonate from eggshells and has: - a grain size DviO less than or equal to 10 pm, preferably less than or equal to 5 pm, - a grain size Dv50 between 10 pm and 30 pm, preferably between 15 pm and 25 pm and - a grain size Dv90 greater than or equal to 40 pm, preferably greater than or equal to 45 pm.

4. Mastic according to claim 1 to 3, which comprises in mass percentages: - between 60% and 75% of said mineral filler, - between 10% and 20% of said polymeric and / or oligomeric composition, this percentage relating to a dry extract in the case where said polymeric and / or oligomeric composition is introduced in the form of an emulsion, - of the quantum satis liquid.

5. A sealant according to any one of claims 1 to 3, which comprises at least less a cellulosic functional filler.

6. Mastic according to claim 5, which comprises, in mass percentages: - between 50% and 72%, preferably between 60% and 72%, very preferably between 68% and 72% of said mineral filler, - between 1% and 5% of said cellulosic functional filler, - between 5% and 20% of said polymeric and / or oligomeric composition, this percentage relating to a dry extract in the case where said polymeric and / or oligomeric composition is introduced in the form of an emulsion, - of the quantum satis liquid.

7. Mastic according to claim 5 or 6, in which said cellulosic functional filler is predominantly of bio-sourced origin and is chosen from functional cellulose, cellulose fiber, wood flour, hemp fiber, hemp residue, lignin powder, wood residue, silvery coffee film.

8. A sealant according to any one of claims 1 to 7, wherein the polymeric and / or oligomeric composition is an acrylic or styrene-acrylic resin with a minimum film-forming temperature of between 0°C and 35°C.

9. A sealant according to any one of claims 1 to 8, which comprises, as functional additives, one or more of the following constituents: - An anti-foaming agent, - A dispersing agent, - A biocidal agent, - A thickening agent, - An antioxidant.

10. Mastic according to any one of claims 1 to 9, which has a bio-sourced carbon content greater than 50%, preferably greater than 60%, and even more preferably greater than 70%.

11. Powdery composition for the preparation of a mastic according to any one of claims 1 to 10, comprising, expressed in mass percentages: - a mineral filler, which consists of at least 30%, preferably 40%, very preferably 50% of calcium carbonate obtained, with a purity of at least 80%, preferably at least 85%, preferably at least 90%, and even more preferably at least 95%, from eggshells. - optionally a cellulosic functional filler.

12. Powdery composition according to claim 11, which has a bio-sourced carbon content greater than 60%, preferably greater than 70%, and even more preferably greater than 80%.

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