FR3100251A1 - COMPOSITE MATERIAL FOR SURFACE COATING AND ITS MANUFACTURING PROCESS - Google Patents

Abstract

This composite material (2) for coating a part of the surface (1) comprises at least waste tires (3), a mineral filler (4) and a binder. The waste tires (3) have a homogeneous particle size between 0 and 7mm, the mineral filler (4) being present in at least two different particle sizes. The invention also relates to a method for producing such a material (2). Figure to be published with abstract: Fig. 1]

Description

COMPOSITE SURFACE COVERING MATERIAL AND METHOD FOR MAKING IT

The present invention relates to a composite surface coating material and its method of production.

The expression "surface covering" here refers to all types of surface, vertical, horizontal or inclined, whether the surface is outdoors or indoors, whatever the material constituting the surface and/or its destination. By way of non-limiting examples, mention may be made of building walls, flat roofs, terraces, playgrounds, car parks, courtyards, floors of industrial or commercial buildings, storage areas. Such coatings are used as sound and/or heat insulation and/or as a decorative element. These coverings form a rolling or walking surface when placed on the ground or any other surface used for movement.

Such coatings generally do not form a structural element of the surface to which they are attached. Also, the constituent material of these coatings must be light and neutral with respect to the constituent material of the surface on which they are fixed. As a result, it has been envisaged to produce composite coatings comprising a mineral filler ensuring the mechanical strength and a part made of polymers conferring flexibility and insulating properties on the coating.

FR-A-2 831 173 teaches a composite product based on plastic waste, with a binder and comprising a mineral filler. Regarding the non-mineral part, the composite comprises ground thermoplastic resins, recycled rubber such as tire crumb and, as a mineral filler, the product may comprise fine or coarse powders such as pozzolan. Other non-mineral filler elements can be added to the composite material Here, the composite material is used as thermal, electrical and sound insulation. This material is based on a variable composition, with numerous components of various origins and natures, which does not make it possible to optimize the characteristics and the homogeneity of the final material.

WO-A-2007/070968 describes a rubber-based composite material that can be used as a surface covering. The material includes bitumen, rubber from tire waste for example, a lightening component such as polystyrene, a binder and, if necessary, a mineral filler which can be pozzolan. Such a material is of complex formulation and, de facto, constitutes a derivative of bitumen. This product resulting directly from oil refining is known to induce health risks for people using it.

Currently, used tires must be recycled. They are used, by way of non-limiting examples, as fuel, backfill material on roads, to make retaining walls, to make industrial protection, shock absorbers on vehicles, playing surfaces on sport, gratings and floor mats for agricultural or industrial use. In the majority of cases, the recycled product is essentially rubber-based, hence the characteristics of the product which remain very similar to those of the initial rubber, or even tyre. In addition, the large amount of rubber from tires can induce inconveniences such as odor which limit its use, for example for playing surfaces, and significant impermeability to water, which induces draining properties limited to the coating of such material. In some cases this can be an advantage but for outdoor flooring it is a disadvantage.

The object of the invention is to propose a composite material for surface covering which allows maximum recycling of rubber coming from tires, simple to produce and having draining properties while retaining thermal and sound insulation properties and offering resistance optimal abrasion.

To this end, the subject of the invention is a composite surface coating material comprising at least waste tires, a mineral filler and a binder, characterized in that the waste tires have a homogeneous particle size between 0 and 7 mm, the mineral filler being present in at least two different particle sizes.

The fact that the mineral filler, formed by pozzolana, is present in at least two different but known grain sizes and each being homogeneous makes it possible, without modifying the general ratio between tire waste and mineral filler, to reinforce the draining properties of the material. without affecting its mechanical strength.

According to advantageous but not mandatory aspects of the invention, such a material may comprise one or more of the following characteristics:

-The mineral filler represents between 40% and 80% by mass of the mixture before adding the binder, the tire waste representing 60% to 20%.

– The mineral filler is formed by pozzolan.

– The material consists of 70% pozzolan for 30% waste tires.

– The material consists of 50% pozzolana and 50% waste tires.

The pozzolan grain sizes present in the material are at least 3 mm to 6 mm and 7 mm to 15 mm, with waste tires having a grain size of 0.5 mm to 2.5 mm or 3 mm to 6 mm .

The invention also relates to a process for producing the composite surface covering material in accordance with one of the preceding characteristics, characterized in that it comprises at least the following steps:

- a) mixture of waste tires and pozzolan according to selected particle sizes,

- b) incorporation into the mixture obtained in the previous step of the binder until a material is obtained which is ready to be distributed over at least part of a surface,

– c) distribution of the material obtained in the previous step over at least part of a surface,

– d) smoothing of the distributed material before complete drying of the binder.

According to advantageous but non-mandatory aspects of the invention, such a method may comprise one or more of the following steps:

– During step c), the part of the surface on which the material is distributed is the surface of a mold of given dimensions.

– Before step d) of smoothing, elements such as LEDs, sound speakers, transducers, RFID tags, electronic identification chips, GPS chips, metallic and/or magnetic elements are incorporated into the material , sensors or others.

The invention will be better understood and other advantages thereof will appear more clearly on reading the following description, given solely by way of non-limiting example and made with reference to the appended drawing in which:

is a simplified perspective view of part of a surface coated with a material in accordance with one embodiment of the invention.

Figure 1 illustrates a surface part 1 on which, as a coating, is laid a material 2 in accordance with one embodiment of the invention. The surface part 1 illustrated here corresponds to a surface intended to allow the movement of people, animals or vehicles, both indoors and outdoors. Such surfaces are found on driveways, parking lots, playgrounds, courtyards of buildings for private, public, commercial or industrial use. In other embodiments, the surface is not intended to allow movement. These are, for example, flat, inclined or vertical areas, located outdoors or indoors and on which you want to put a protective and/or decorative coating. By way of non-limiting examples, mention may be made of plant or forest plantation protection, walls or inclined planes of buildings, street furniture or works of art, solid land, embankments of traffic lanes, roof terraces or others. In all cases, whatever the surface on which the material 2 is placed, the latter is held in position on the surface 1 by means known per se.

Thereafter, a preferred embodiment will be described, in order to facilitate reading, in which the material 2 is used as a coating for a part of the surface 1 intended for the movement of people and/or vehicles. In such a case, either the material 2 is shaped directly on the surface part 1 or it is preformed, for example in square slabs which are then positioned on the surface part 1. In all cases, the material is adherent on most surfaces encountered, for example, concrete, plastic, wood, stone, ceramic or a natural surface. These adhesion properties facilitate its installation, without it being systematically necessary to fix the material by known means such as screwing or gluing in the case of a preformed slab. The method of using the material will be described later.

Material 2 is a composite material with at least three essential components: tire scrap, mineral filler, and binder.

Tire waste comes in the form of aggregates 3 also known as SBR (Styrene Butadiene Rubber) or crumb. Subsequently, to facilitate reading, the term powder will be used. The crumb 3 is of known and homogeneous particle size. Crumb 3 does not include any additive and is composed of dried rubber particles, with a bulk density close to 0.4.

As a variant, the crumb 3 also comprises rubber originating from products other than tires, for example conveyor belts, belts, straps, damping elements or any other rubber product and of an identical composition, or at least similar, to that of tires.

The particle size of crumb 3 is generally between 0 and 7 mm Advantageously, the crumb used for the material that is the subject of the invention is a crumb benefiting from a certificate of conformity guaranteeing that the tires have been placed on the market by meeting all the requirements in terms of approval and that the crumb was obtained by mechanical processes, without the addition of additives. Crumb 3 is supplied in three grain sizes corresponding to the main needs of the market.

The crumb 3 with the finest grain size, between 0 and 0.8 mm with a distribution such that 61% of particles has less than 0.71 mm. This crumb will be referenced later PnF.

A crumb 3 of average particle size, between 0.5 mm and 2.5 mm with a distribution such that 77% of the particles are less than 2 mm. This crumb will be referenced later PnM.

A crumb 3 of high particle size, between 3 mm and 6 mm with a distribution such that 87% of the particles are less than 5 mm. This crumb will be referenced later PnG.

It is understood that, in the context of the invention, it is possible to use other particle sizes than those mentioned or more than three particle sizes, depending on the desired final coating and/or the type of surface to be covered.

In addition to crumb 3, material 2 comprises a mineral filler 4. Advantageously, the mineral filler is pozzolana 4. As a variant, the mineral filler is of another nature or complex, for example formed of pozzolana associated with other mineral fillers like pumice, diatomite, dead coral or whatever. In all cases, the mineral filler must provide mechanical resistance without weighing down the material.

For the record, pozzolana is a rock of natural volcanic origin consisting of basaltic volcanic scoria or of similar composition. It has an alveolar structure. It has been known since Roman times as a constituent of a mortar that hardens over time and, in particular, when it comes into contact with seawater. It has excellent thermal and acoustic insulation and its ability to absorb varies from 20% to 30% by dry weight. It is used, for example, in horticulture, in landscaping as mulching and/or to avoid soil compaction, in agriculture to lighten soils, constructions, concrete, in the composition of cements, in the winter treatment of roads , for floors of sports facilities such as racetracks, athletics tracks, tennis courts. Pozzolan, because of its porosity, constitutes a good bacterial support and a good filter. It is thus used in on-site sanitation, treatment of drinking water, lagooning, aquariums.

Its extraction is done in volcanic regions. In mainland France, Auvergne is the main supplier of pozzolan. Pozzolan is marketed in a wide range of grain sizes to cover all needs. By way of non-limiting example, the company POUZZOLANE DES DOMES, which is one of the pozzolana producers based in the Puy de Dôme, offers pozzolana whose particle size ranges from 0 mm to 100 mm.

Pozzolan 4 is supplied here in three grain sizes corresponding to the main needs of the market.

A pozzolan 4 of the finest grain size, between 0 and 0.3 mm. This pozzolan will be referenced hereafter PoF.

A pozzolan 4 of medium grain size, between 3 mm and 6 mm. This crumb will be referenced later PoM.

A crumb 3 of high particle size, between 7 mm and 15 mm. This coarse pozzolana 4 will be referenced hereafter PoG.

It is understood that, in the context of the invention, it is possible to use other particle sizes than those mentioned or more than three particle sizes, depending on the desired final coating and/or the type of surface to be covered.

The binder used in the preferred mode of the invention is a polyurethane resin hardening with the humidity of the air. It has a setting time of about 30 minutes and, once hardened, remains relatively flexible. These characteristics allow easy implementation, whatever the surface to be covered and allows direct placement of the coating on the surface, including outdoors. t In other embodiments, other types of binder are employed. These are, for example, natural resins, based on polymers or a binder with a complex composition.

The applicant has carried out several tests during which the ratio between the pozzolan and the crumb varies. In order to optimize the material, that is to say to obtain the best compromise between the various characteristics of each of the constituents while preserving an aesthetic appearance of the coating and limiting the possible nuisances linked to an excessively high percentage of crumb, in particular smell, it was decided to produce a material containing between 40% and 80% pozzolan and between 60% and 20% crumb. Advantageously, according to a first embodiment, the percentage of pozzolan is between 65% and 75% and that of crumb between 35% and 25%. Preferably, a material of optimal composition according to this first embodiment has a pozzolan percentage close to 70% for 30% crumb.

According to a second embodiment of the invention, the percentage of pozzolan is between 40% and 60%, that of crumb between 60% and 40%. Advantageously, in this second embodiment, the percentages of pozzolan and crumb are each close to 50%

The percentages of the first and second embodiments are given by mass on the raw mixture of pozzolan and crumb, before adding the binder and any other additives.

In order to ensure the holding of the raw mixture, pozzolan and crumb, the binder is added at a rate of up to approximately 20% by mass of the final material.

It is understood that to these basic components, additives are added if necessary. These include, for example, colorants, setting retarders, setting accelerator, perfumes, deodorizers, antifreeze, fungicides, biocides or others. It is also possible to incorporate elements into the material, before the binder has set. By way of non-limiting example, mention may be made of temperature, pressure, humidity and sunlight sensors, RFID tags, electronic identification chips, GPS beacons, lighting, sound transducers , loudspeakers, communication devices or others.

The applicant has found, surprisingly, that when the mineral filler is present in the material in at least two different particle sizes, the crumb being present in one particle size, the characteristics of the material are optimized. In particular, a material is obtained which has draining properties superior to those of draining mixes known from the state of the art, this by having thermal insulation characteristics comparable to those of wood and sound absorption double those of of a draining coating.

The tests have shown in particular that a material comprising a pozzolan filler with two different grain sizes corresponding to PoM and PoG, therefore between 3 and 6 mm and between 7 and 15 mm, makes it possible to obtain an optimized material when the percentage of crumb corresponds to PnM or PnG, i.e. a grain size of 0.5 to 2.5 mm or 3 to 6 mm.

Tests were also carried out with pozzolan present in all three grain sizes, therefore with PoF, PoM and PoG. In this case, the presence of PoF, therefore of pozzolan with a grain size between 0 and 0.3mm, increases the mechanical resistance of the material as well as its acoustic insulation properties but reduces its drainage capacities. The presence of three pozzolan grain sizes also affects the natural color of the material, with the latter being redder.

A material with PoM, PoG and PnG will be noticeably redder than a material with PoM, PoG and PnM composition.

Tests carried out with a material of PoM, PoG and PnG composition give a maximum bending resistance Rfmax of 141N for a displacement of 12 mm. The material exhibits a deformation of 10% for an exerted stress of 0.55 MPa. In other words, such a material has a high elastic deformability, a damping character and a high ductility at break.

The thermal conductivity is 0.1148 W/mk, the diffusivity 34.8 m ² /s and the effusivity 445 Ws ^1/2 /m ² /K. The material therefore has insulating properties similar to those of wood. Its thermal conductivity is better than that of asphalt mixes commonly used to make a road surface, which reduces the ability to absorb and release heat. Furthermore, no loss of mass is observed after the freeze/thaw cycles, this being associated with excellent resistance to freezing of the material.

The drainage performance of the material has been measured according to the standard in force. Thus, with a coating with a thickness of 3 cm, the percolation speed Vperc is 4.7 cm/s, knowing that a material is considered to be draining from Vperc = 1cm/s. The material is therefore approximately four times more draining than a conventional porous asphalt, it being understood that depending on the formulations chosen, and therefore according to the grain sizes selected, the material is two to five times more draining than a conventional asphalt.

The sound absorption capacities, according to the alpha sabine absorption coefficient, are 0.6. In other words, the material is twenty times more absorbent, at the acoustic level, than an asphalt and twice as much as a porous asphalt.

Such a material can be implemented according to a process which is also the subject of the invention. In a first step, depending on the coating to be carried out, therefore, for example, depending on the desired color, whether the coating must be above all draining, thermally insulating, soundproofing, whether the surface to be coated is horizontal or not, depending on the thickness desired coating or other criteria, the particle sizes of crumb 3 and pozzolan 4 will be chosen.

If necessary, other elements will be chosen and will form an additional load on the material. These are, for example, dye, setting retarder or accelerator, antifreeze, metallic and/or magnetic filler, electronic markers such as RFID or GPS chips, sensors. In all cases, these additional elements remain in the minority and do not significantly modify the characteristics of the material.

Once the particle sizes of pozzolan 4 and crumb 3 have been selected, these components, with any additional elements, are mixed until a homogeneous mixture is obtained.

The next step consists of incorporating a binder, here a polyurethane resin, into the homogeneous mixture obtained previously. The incorporation of the binder can be done either immediately following the mixing step or later. In the latter case, the homogeneous mixture is supplied ready to use to the user who will incorporate the binder just before the final placement of the material. In this way, it is possible to provide mixtures of crumb 3 and pozzolan 4 with particle sizes adapted to given needs and ready to use.

Once the binder has been incorporated into the homogeneous mixture, the latter is ready to be distributed over at least part of a given surface. This surface is, in one embodiment, the final surface intended to receive the material. Typically, this embodiment is encountered when the ready-to-use mixture is directly distributed on an indoor or outdoor floor, a traffic lane, a playground, a parking lot, a sports field.

According to another embodiment, the surface concerned is that of a mold. In this case, slabs are produced, of pre-established thickness and dimensions, of material. These slabs will then be used to cover at least part of a surface, similar to a ceramic slab or a paving stone. In such an embodiment, it is thus possible to store, transport and use the material in a place and/or a time remote from its place and/or time of production.

Once the mixture has been distributed over the surface concerned, whether it is the final surface or that of a mould, the surface of the distributed mixture is smoothed, before the binder has completely dried, in order to obtain a flat outer face. As a variant, it is possible during this smoothing phase to give a decorative appearance to the outer face of the material, for example by smoothing with a suitable tool to create reliefs, waves or the like.

In another embodiment, before smoothing, once the mixture has been distributed over the surface, components such as LEDs, sensors, sound speakers, transducers, electronic identification chips, GPS chips, RFID tags, metallic and/or magnetic or other elements. This operation is carried out before smoothing and especially before the binder dries, the aim being that these elements are taken into the mass of the material and, if necessary, isolated from the outside by a layer of binder.

In other embodiments, the surface is coated with at least two layers of materials having different grain sizes, at least for one of the two components, crumb 3 or pozzolan 4. These layers of materials may or may not be of the same thickness. . They can also be separated by a layer of another material, the latter possibly being structured like a film of polymers or not like a layer of mineral origin.
F

Claims (9)

Composite surface coating material (2) (1) comprising at least waste tires (3), a mineral filler (4) and a binder, characterized in that the waste tires (3) have a homogeneous particle size between 0 and 7mm, the mineral filler (4) being present in at least two different grain sizes. Material according to Claim 1, characterized in that the mineral filler (4) represents between 40% and 80% by mass of the mixture before addition of the binder, the waste tires (3) representing from 60% to 20%. Material according to Claim 2, characterized in that the mineral filler is formed by pozzolan (4). Material according to Claim 3, characterized in that the material (1) comprises 70% pozzolan (4) and 30% tire waste (3). Material according to Claim 3, characterized in that the material (1) comprises 50% pozzolan (4) and 50% tire waste (3). Material according to one of Claims 3 to 5, characterized in that the particle sizes of the pozzolan (4) present in the material (1) are at least from 3 mm to 6 mm (PoM) and from 7 mm to 15 mm ( PoG), waste tires (3) having a grain size of 0.5 mm to 2.5 mm (PnM) or 3 mm to 6 mm (PnG). Process for producing the material (2) in accordance with one of Claims 3 to 6, characterized in that it comprises at least the following steps:
a) mixture of waste tires (3) and pozzolan (4) according to selected particle sizes,
b) incorporation into the mixture obtained in the previous step of a binder until a material is obtained which is ready to be distributed over at least part (1) of a surface,
c) distribution of the material obtained in the previous step over at least part (1) of a surface,
d) smoothing of the distributed material before the complete drying of the binder. Process for producing the material (2) according to Claim 7, characterized in that during stage c), the surface part (1) over which the material (2) is distributed is the surface of a mold of dimensions data. Process for producing the material (2) according to one of Claims 7 or 8, characterized in that before step d) of smoothing, elements such as LEDs, sound speakers, transducers, RFID tags, electronic identification chips, GPS chips, metallic and/or magnetic elements, sensors.