Roofing element comprising at least one composition including a halogenated thermoplastic polymer and a rubber powder

Abstract

Roofing element comprising at least one composition comprising at least one halogenated thermoplastic polymer and at least one rubber powder. The present invention relates to a roofing element, such as a slate, comprising at least one composition comprising: - at least one halogenated thermoplastic polymer; - 10% to 40% by mass of at least one rubber powder relative to the total mass of the composition and being obtained by a specific process.

Description

Title of the invention: Roofing element comprising at least one composition comprising a halogenated thermoplastic polymer and a rubber powder

[0001] The present invention relates to roofing elements, such as a slate, and more particularly to roofing elements comprising a composition including a halogenated thermoplastic polymer and a rubber powder. technical field

[0002] In the construction of structures, particularly buildings, the roof of the structure must be able to protect the interior of the structure from the external environment, but also to provide a desired aesthetic appearance. The roof of the structure must therefore be made of roofing elements that have, in particular, weather-resistant properties.

[0003] Today, various materials have been used to achieve these objectives, such as slate tiles or fiber cement tiles, etc. These tiles are generally relatively heavy due to their high density, do not have satisfactory resistance properties, and their aesthetic appearance is not necessarily pleasing. Furthermore, there remains a need to improve the impact resistance of roofing elements, particularly to extend their lifespan in the event of severe weather such as hailstorms.

[0004] To this end, the Applicant discovered, surprisingly and at the cost of significant research efforts, that a roofing element comprising a particular composition, containing a halogenated thermoplastic polymer and a rubber powder, obtained by a process including in particular a step of injecting the particular composition into a mold heated to a high temperature, made it possible to obtain advantageous properties, in particular in terms of the impact resistance of roofs, while also surprisingly improving the encapsulation of the rubber powder in the composition.

[0005] By "gum powder encapsulated in a composition," we mean a gum powder that is perfectly coated by the composition containing it; we then say that there is good encapsulation of the gum powder in the composition. Conversely, when at least part of the gum powder is not coated in the composition, but is exposed on the surface of a sample of the composition and could easily detach by simple surface friction, we speak of "free gum powder," or poor encapsulation of the gum powder. gum in the composition.

[0006] However, during certain manufacturing processes of the roofing element, the rubber powder may not be well encapsulated in the composition, meaning that a significant proportion of free rubber powder remains, easily detaching from the roofing element and generating dust that is troublesome during handling, for example, during installation. The invention overcomes this industrial drawback.

[0007] The present invention therefore relates first to a roof covering element comprising at least one composition A comprising: - a halogenated thermoplastic polymer; - from 10% to 40% by mass of at least one powder of gum relative to the total mass of composition A; obtained by a process comprising at least the following steps: a) a manufacturing step of composition A by mixing all the constituents in a mixing unit; b) a step of injecting composition A into a mold heated to a temperature above 110°C so as to obtain the roof covering element.

[0008] Another object of the invention is a method for manufacturing a roofing element comprising at least the following steps: a) a manufacturing step of a composition A by mixing in a mixing unit all the constituents of composition A which includes at least one halogenated thermoplastic polymer and 10% to 40% by mass, relative to the total mass of composition A, of at least one gum powder; b) a step of injecting composition A into a mold heated to a temperature above 110°C so as to obtain the roof covering element.

[0009] The roof covering element according to the invention makes it possible to obtain advantageous properties, in particular in terms of impact resistance and encapsulation of the rubber powder in composition A.

[0010] A roofing element with higher impact resistance increases the lifespan of the roof on which it is installed. Indeed, in the event of hail, for example, a roofing element with higher impact resistance will not break, or will crack later, so that the roofing elements will need to be removed and replaced less frequently, resulting in savings in labor time, material costs and quantity of materials, with a positive environmental impact.

[0011] Furthermore, a roofing element with improved encapsulation of the gum powder within composition A of the roofing element allows for easier handling of the roofing element. Indeed, During the transport or installation of a roofing element comprising composition A, if any gum powder is loose from composition A, it can easily detach from the roofing element and cause it to slip in the operator's hands or generate dust in the storage area, for example. Therefore, a roofing element not containing loose gum powder offers a clear advantage in terms of industrial efficiency.

[0012] Other features and advantages of the invention will become clearer upon reading the following description and examples. Description of the invention

[0013] Any interval of values ​​designated by the expression "between a and b" represents the domain of values ​​going from more than a to less than b (that is to say, bounds a and b excluded) while any interval of values ​​designated by the expression "from a to b" means the domain of values ​​going from a to b (that is to say, including the strict bounds a and b).

[0014] The expression "at least one" is equivalent to the expression "one or more".

[0015] The compounds mentioned in the description may be of fossil origin or bio-based. In the latter case, they may be partially or totally derived from biomass or obtained from renewable raw materials derived from biomass. This includes, in particular, polymers, plasticizers, fillers, etc.

[0016] Furthermore, the compounds mentioned in the description may be derived from Recycling. For example, a material such as rubber dust can come from used tires or, more generally, from used materials. Another material, such as polyvinyl chloride, can come from used products, for example, those from carpentry, shutters, pipes, etc.

[0017] According to a first aspect, the invention relates to a roof covering element comprising at least one composition A comprising:

[0018] - a halogenated thermoplastic polymer;

[0019] - from 10% to 40% by mass of at least one powder of gum relative to the mass total of composition A;

[0020] obtained by a process comprising at least the following steps:

[0021] a) a manufacturing step of composition A by mixing all the constituents in a mixing unit;

[0022] b) a step of injecting composition A into a mold heated to a temperature above 110°C so as to obtain the roof covering element.

[0023] Preferably, the halogenated thermoplastic polymer consists of more than 75% by mass, preferably more than 90% by mass, and even more preferably 100% by mass of units derived from one or more monomers comprising at least one halogen atom. More preferably, the monomer(s) comprising at least halogen atoms are chosen from vinyl tetrafluoride, vinyl fluoride, vinylidene fluoride, ethylene chlorotrifluoride, vinyl chloride, superchlorinated vinyl chloride, vinylidene chloride, and mixtures of these monomers, and more preferably, the monomer comprising at least one halogen atom is vinyl chloride.

[0024] Advantageously, the halogenated thermoplastic polymer is present at a mass percentage ranging from 45% to 90%, preferably from 55% to 90% relative to the total mass of composition A.

[0025] Advantageously, the halogenated thermoplastic polymer has a weight molecular mass Mw ranging from 50,000 to 250,000 g / mol, preferably from 60,000 to 200,000 g / mol, more preferably from 90,000 to 200,000 g / mol.

[0026] Preferably, the rubber powder comprises a vulcanized rubber composition B including at least one elastomer and at least one filler Cl. More preferably, the elastomer is selected from diene elastomers, alone or in mixtures. Advantageously, the filler Cl is a reinforcing filler, preferably selected from carbon blacks. Preferably, the mass percentage of filler Cl is between 5% and 80%, preferably between 10% and 60%, and most preferably between 15% and 40% by mass relative to the total mass of the rubber powder.

[0027] Advantageously, the gum powder has an average particle size (D50) between 50 and 800 pm, preferably between 200 and 600 pm.

[0028] Preferably, the gum powder is present at a mass rate ranging from 10% to 35% by mass relative to the total mass of composition A.

[0029] Advantageously, the mold is heated to a temperature ranging from 115°C to 220°C, preferably from 120°C to 200°C, more preferably from 120°C to 180°C.

[0030] Preferably, composition A comprises from 0 to 20%, preferably from 5% to 15% by mass relative to the total mass of composition A of a filler C2. More preferably, the filler C2 is an inorganic filler; even more preferably, the filler C2 is selected from clays, bentonites, talcs, chalks, kaolins or graphites or mixtures thereof; preferably the filler C2 is a chalk.

[0031] The invention also relates to a method for manufacturing a roofing element comprising at least the following steps:

[0032] a) a manufacturing step of a composition A by mixing in a mixing unit all the constituents of composition A which includes at least one halogenated thermoplastic polymer and 10% to 40% by mass, relative to the total mass of composition A, of at least one gum powder;

[0033] b) a step of injecting composition A into a mold heated to a temperature Temperature above 110°C to obtain the roofing element. Halogenated thermoplastic polymer

[0034] As previously stated, the roof covering element according to the invention comprises at least one composition A comprising a halogenated thermoplastic polymer.

[0035] For the purposes of this invention, thermoplastic polymer means a polymer having a glass transition temperature, or a melting temperature in the case of semi-crystalline polymers, greater than or equal to 80°C, preferably from 80°C to 250°C, more preferably from 80°C to 200°C, and in particular from 80°C to 180°C.

[0036] Indeed, in the case of a semi-crystalline polymer, a melting temperature higher than the glass transition temperature can be observed. In this case, the melting temperature, and not the glass transition temperature, is taken into account for the definition above.

[0037] It is clear that a thermoplastic polymer within the meaning of the present invention is different from a thermoplastic elastomer.

[0038] For the purposes of this invention, halogenated thermoplastic polymer means a thermoplastic polymer as defined above, comprising units derived from one or more monomers, at least one of which comprises at least one halogen atom, such as fluorine, chlorine, bromine, iodine, preferably fluorine and chlorine, more preferably chlorine.

[0039] By average molecular mass of a halogenated thermoplastic polymer, we preferably mean the average molecular mass by weight (Mw).

[0040] Preferably, the halogenated thermoplastic polymer(s) are made up of more than 75% by mass, preferably more than 90% by mass, even more preferably 100% by mass, of units derived from one or more monomers comprising at least one halogen atom.

[0041] Preferably, the monomer or monomers comprising at least one halogen atom are chosen from vinyl tetrafluoride, vinyl fluoride, vinylidene fluoride, ethylene chlorotrifluoride, vinyl chloride, superchlorinated vinyl chloride, vinylidene chloride, and mixtures of these monomers, and more preferably the monomer comprising at least one halogen atom is vinyl chloride.

[0042] Advantageously, the halogenated thermoplastic polymer(s) are present at a mass rate of 45% to 90% by mass, preferably 55% to 90% by mass relative to the total mass of composition A.

[0043] Said composition A may optionally comprise one or more thermoplastic polymers other than the halogenated thermoplastic polymers described above. previously.

[0044] Examples of such polymers may include, in particular, acrylonitrile, butadiene and styrene copolymers (ABS copolymers), ethylene and vinyl acetate (EVA) copolymers, and mixtures thereof.

[0045] When present in composition A, non-halogenated thermoplastic polymers preferably represent a mass percentage less than or equal to 30% by mass, more preferably from 0 to 15% by mass relative to the total mass of composition A.

[0046] More preferably, composition A comprises as a thermoplastic polymer only one or more halogenated thermoplastic polymers according to the invention as described above.

[0047] Advantageously, said halogenated thermoplastic polymer has a weight average molecular mass (Mw) of 50,000 to 250,000 g / mol, preferably of 60,000 to 200,000 g / mol.

[0048] More preferably, the halogenated thermoplastic polymer has a weight-average molecular weight (Mw) ranging from 90,000 to 200,000 g / mol. This latter preferred Mw range is particularly relevant to halogenated thermoplastic polymers derived from the recycling of used products, typically recycled polyvinyl chlorides, whose Mw is not necessarily suitable for the injection molding process. Indeed, during the recycling of halogenated thermoplastic polymers from used products, no step is included to sort or separate halogenated thermoplastic polymers designed for injection molding processes, which generally have a lower Mw than others, from those designed, for example, for extrusion processes, which may have a higher Mw.However, a composition comprising at least one of these halogenated thermoplastic polymers and 10% to 40% by mass of a rubber powder relative to the composition's mass is likely, after an injection step of said composition into a mold, to contain free rubber powder, i.e., powder not encapsulated within the composition. Thus, one of the advantages of the invention is to enable the production of a roofing element comprising a halogenated thermoplastic polymer and 10% to 40% by mass of at least a rubber powder relative to the total mass of the composition, without containing any free rubber powder, even after an injection step of the composition into a mold under the conditions provided for by the invention. Gum powder

[0049] As previously stated, composition A comprises from 10% to 40% by mass of at least one powder of gum relative to the total mass of composition A.

[0050] Gum powders may be commercially available.

[0051] It is recalled that gum powders are generally in the form of granules (or granulates), possibly in the form of a rubber sheet. Most often, rubber powders are a recycled material product: they result from grinding, particularly micronization, of cured rubber compositions already used for a first application, for example as tire curing membranes (as in document US6730732) or as end-of-life tires (as in document KR100943526). Any method or process that does not degrade the rubber during grinding is suitable as a method for grinding rubber compositions. For example, one could choose a grinding method in the presence of water such as those described in documents US4374573, US4714201, US5238194 and US5411215: such a method makes it possible to keep the temperature of the gum at a level low enough to avoid reversion, that is to say the degradation of the crosslinking network of the gum.A cryogenic grinding method can also be used. Commercial equipment such as the Netzsch CUM150 or Alpine CW250 mills can be used. Depending on the resulting object size distribution, the rubber powder obtained by the aforementioned processes may undergo an additional sieving step to control this distribution. Sieving can be carried out using various technologies (vibration, centrifugation, aspiration) known to those skilled in the art. The rubber powders produced by the grinding process are generally in the form of microparticles. By "microparticles," we mean particles whose size—namely their diameter in the case of spherical particles or their largest dimension in the case of anisotropic particles—is on the order of tens or hundreds of microns.

[0052] Preferably, the rubber powder comprises a vulcanized rubber composition B comprising at least one elastomer and at least one filler CL

[0053] The elastomer may be chosen from among diene elastomers, alone or in mixtures.

[0054] The term "filler" means any type of filler well known to those skilled in the art. Preferably, the filler Cl is any type of reinforcing filler known for its ability to strengthen a rubber composition, for example, an organic filler such as carbon black, a reinforcing inorganic filler such as silica or alumina in the presence of a coupling agent, or mixtures thereof, for example, a cutting agent of these two types of filler.

[0055] According to a preferred embodiment of the invention, the gum powder comprises, as filler Cl, a reinforcing filler chosen from among carbon blacks.

[0056] According to a more preferred embodiment of the invention, the reinforcing filler consists of carbon black or a mixture of carbon blacks.

[0057] All carbon blacks are suitable as carbon blacks, in particular blacks of the type HAF, ISAF, SAF, FF, FEF, GPF and SRF conventionally used in tire rubber compositions (so-called tire grade blacks).

[0058] According to a preferred embodiment of the invention, the gum powder contains between 5% and 80% by mass, more preferably between 10% and 60% by mass, very preferably between 15% and 40% by mass of filler Cl relative to the total mass of the gum powder.

[0059] The rubber powder may contain all other common additives that are part of a rubber composition. These common additives include vulcanizing agents, non-reinforcing fillers such as chalk and kaolin, and preservatives. These additives may also be found in the rubber powder in the form of residues or derivatives, since they may have reacted during the manufacturing or crosslinking stages of the rubber composition contained in the rubber powder, or they may have changed during use in the case of rubber powder derived from end-of-life products.

[0060] It is also known that these gum powders can undergo treatment in order to modify them. This treatment may consist of a chemical modification for functionalization or devulcanization. It may also be a thermomechanical, thermochemical, biological treatment...

[0061] According to a first embodiment, preferred of the invention, it is possible to use a gum powder that has not undergone modification by thermal and / or mechanical, and / or biological and / or chemical treatment.

[0062] Preferably also according to this first embodiment of the invention, the gum powder has an average particle size (D50) between 50 and 800 mm, preferably between 200 and 600 mm.

[0063] According to a second embodiment of the invention, it is possible to use a gum powder which has a morphology modified by thermal and / or mechanical, and / or biological and / or chemical treatment.

[0064] Advantageously, the gum powder is present at a mass concentration ranging from 10% to 35% by mass relative to the total mass of composition A. Other possible additives

[0065] Composition A according to the invention optionally also comprises various additives, such as mineral (i.e. inorganic) or organic fillers, such as chalk, kaolin, wood powder, etc., pigments, such as carbon black, titanium dioxide, mineral pigments such as metal oxides or organic pigments, mineral or organic flame retardants, stabilizers, protective agents such as antioxidants, photoprotective agents, such as anti-UV agents, rheological additives such as plasticizers, lubricants, mineral powder, etc.

[0066] According to a preferred embodiment of the invention, composition A comprises from 0 to 20%, preferably from 5% to 15% by mass of the total mass of composition A, of a filler C2, filler C2 being an inorganic filler. Suitable inorganic fillers for C2 are preferably clays, bentonites, talcs, chalks, kaolins, graphites, or mixtures thereof. More preferably, filler C2 is chalk.

[0067] According to a preferred embodiment of the invention, composition A further comprises at least one additive, preferably selected from pigments such as carbon black, mineral powders and mixtures thereof.

[0068] Advantageously, the additive is present at a mass concentration ranging from 0.2% to 20% in mass relative to the total mass of composition A. Preparation of compositions

[0069] Composition A useful for the needs of the invention can be obtained by mixing all of its constituents during a step a) in a mixing unit commonly used for the production of compositions comprising a halogenated thermoplastic polymer.

[0070] According to a first embodiment of the invention, this step a) comprises two phases. The first, called "dry blending," consists of mixing the halogenated thermoplastic polymer in powder form and the additives in a first hot tank (at a temperature between 80 and 120°C) and then continuing the mixing and ensuring cooling in a cold tank (ambient temperature). The second phase consists of introducing the mixture obtained at the end of the first phase into an extrusion machine heated between 130 and 200°C, resulting in a rod at the die exit, which is then cooled and granulated to produce granules of composition A.

[0071] According to this first embodiment of the invention, the gum powder can be introduced either during the first phase of "dry tank mixing", with all the constituents of composition A, in the hot tank; or during the second phase, into the feed hopper of the extrusion machine.

[0072] When the halogenated thermoplastic polymer is a recycled halogenated thermoplastic polymer, it can be introduced either during the first phase or during the second phase.

[0073] According to another embodiment of the invention, all the constituents of composition A are introduced during a single mixing-extrusion phase in an extrusion machine. When the halogenated thermoplastic polymer is a recycled halogenated thermoplastic polymer, the single mixing-extrusion phase is generally preferred: the recycled halogenated thermoplastic polymer, the rubber powder, and the various additives are introduced into the hopper. feeding of the extrusion machine. According to this embodiment of the invention, the additives can be introduced in the form of a masterbatch supported in a halogenated thermoplastic polymer base, such as a PVC base.

[0074] According to another embodiment of the invention, the various constituents of composition A are introduced successively into an internal haake-type mixer or into a calender heated between 130°C and 190°C. The mixing is carried out for a period of 1 to 5 minutes. Manufacturing of roofing elements

[0075] A roof covering element according to the invention can be obtained by injecting composition A obtained in step a) described above into a mold heated to a temperature above 110°C for a period of 15 to 30 seconds before lowering the temperature of the mold to a temperature of 40 to 60°C in a time of between 45 and 120 seconds so as to obtain a roof covering element with a width of between 200 and 400 mm, a length of between 300 and 800 mm and a thickness of between 2.5 and 5 mm.

[0076] It is important that the mold be initially heated to a temperature significantly higher than the glass transition temperature (as defined previously) of the halogenated thermoplastic polymer, so that the polymer has sufficient molecular mobility at the time of molding. Thus, if the mold is heated to a temperature below 110°C, this temperature will be too close to the glass transition temperature of polyvinyl chloride, which has a glass transition temperature of 95°C, and there is a risk of obtaining a roofing element with loose rubber dust.

[0077] Advantageously, the composition A obtained in step a) is injected into a mold heated to a temperature ranging from 115°C to 220°C, preferably from 120°C to 200°C, more preferably from 120°C to 180°C. These preferred mold temperature ranges improve the encapsulation of the rubber powder in composition A and the impact resistance of the roofing element comprising composition A.

[0078] The invention also relates to a method for manufacturing a roofing element according to the invention, that is to say a method comprising at least the following steps: a) a manufacturing step of composition A by mixing in a mixing unit all the constituents of composition A (as described in the section "Preparation of compositions"); b) an injection step of composition A obtained in step a) into a mold heated to a temperature above 110°C so as to obtain the roof covering element according to the invention; Composition A comprising, as previously described, at least one halogenated thermoplastic polymer and 10% to 40% by mass, relative to the total mass of composition A, of at least one powder of gum.

[0079] The following examples illustrate the invention without however limiting it. Examples

[0080] In the examples, the roof covering elements, the halogenated thermoplastic polymers and the rubber powders are characterized as indicated below. 1. Characterization Methods a. Measurement of particle size

[0081] The particle size (in particular D50) can be measured by laser particle size analysis using the "Mastersizer 3000" from Malverne. The measurement is performed in liquid form, with dilution in alcohol after a preliminary ultrasonic treatment of 1 minute 10 seconds to ensure particle dispersion. The measurement is performed in accordance with ISO 13320-1. b. Molecular mass measurement

[0082] The SEC (Size Exclusion Chromatography) technique is used, which allows macromolecules in solution to be separated according to their size through columns filled with a porous gel. The macromolecules are separated according to their hydrodynamic volume, with the largest being eluted first.

[0083] SEC (PS calibration): The SEC is coupled to a refractometer, in which case it provides relative information. From commercial standard products, the various number-average (Mn) and weight-average (Mw) molar masses that characterize the polymer's molar mass distribution can be determined, and the polymolecularity index (Ip = Mw / Mn) calculated via a Moore calibration. No special treatment of the polymer sample is required before analysis. It is simply solubilized in the elution solvent at a concentration of approximately 1 g / L. The solution is then filtered through a 0.45 µm porosity filter before injection.

[0084] The apparatus used is a "WATERS alliance" chromatographic system. The elution solvent is tetrahydrofuran, the flow rate is 1 mL / min, the system temperature is 35°C, and the analysis time is 45 min. A set of three AGILENT (Mixed BLS) columns is used. The injected volume of the polymer sample solution is 100 pL. The detector is a "WATERS 2414" differential refractometer, and the chromatographic data processing software is the "WATERS EMPOWER" system.

[0085] The calculated average molar masses are relative to a calibration curve made from commercial standard polystyrenes “PSS READY CAL-KIT”.

[0086] c. Characterization of the encapsulation of the gum powder

[0087] The characterization of the encapsulation of the rubber powder is essentially visual: if the rubber powder is observed to be flush with the surface of the roofing element, protruding from it and able to detach when the hand passes over it, then the rubber powder is considered to be free and not encapsulated. If, on the other hand, the surface of the roofing element is smooth, without any flush rubber powder detaching from it, then the rubber powder is well encapsulated.

[0088] This observation can also be complemented by an analysis of the average surface roughness by any method adapted to the size scale of the rubber powder, such as a roughness measurement by laser optics. d. Impact resistance measurement

[0089] To measure the impact resistance of a roofing element, it is held at both ends in clamping devices and then subjected to the impact of a 500g ball dropped from a given height. It is then observed whether the impact (or shock) has caused a through crack to appear in the roofing element, that is, a crack visible on both the upper and lower faces of the roofing element. If not, the same procedure is repeated for a greater drop height. The breaking energy is calculated as the energy of the ball that caused the first through crack, given by the formula: Erupture Habille X hchute X g where: - mbiiie is the mass of the ball, i.e. 500g; - hchute is the height from which the ball was dropped; - g is the acceleration due to gravity, taken as 9.8 m / s².

[0090] The term "impact resistance index" means the value of this breaking energy expressed as a base of 100 relative to the control: the higher the impact resistance index, the better the impact resistance performance. 2. Preparation of roofing elements

[0091] The compositions are manufactured by introducing all the constituents into a twin-screw extrusion machine for rigid PVC, heated to 180°C and operating at a flow rate of 200 to 450 kg / h.

[0092] The comparative roofing elements T1, T2, T3, T'3, T4 and T'4, and the roofing elements E1, E2 and E3, according to the invention, are made up of compositions prepared on the basis of the constituents as described in Table 1 below, where the contents are expressed as % by mass of the total mass of the composition.

[0093] Then, each of the compositions is injected into a mold heated to the temperature indicated in Table 1 below so as to obtain a plate, which can thus represent a roof covering element.

[0094] [Tables 1] T1 El T2 E2 T3 T'3 E3 T4 T'4 PVC 1 (1) 85 85 70 70 PVC 2 (2) 70 70 70 PVC 3 (3) 70 70 Gum powder (4) 15 15 30 30 30 30 30 30 30 Mold temperature [°C] 30 150 30 150 30 110 150 30 110 1. Polyvinyl chloride (PVC) polymer “Evervinyl EXTRI G0M6” marketed by the company Paprec (Mw = 152,065 g / mol); 2. Polyvinyl chloride (PVC) polymer “Lacovyl S-RB S071 / S” marketed by the company Kem One (Mw > 130,000 g / mol?); 3. Polyvinyl chloride (PVC) polymer “Vinika VRIN713” marketed by the company Vinika (Mw = 75,786 g / mol); 4. "MRP Microdyne 830 TR" gum powder, marketed by Lehigh Technologies 3. Results

[0095] The results are summarized in Table 2 below.

[0096] [Tables2] Performance Tl El T2 E2 T3 T'3 E3 T4 T'4 Encapsulated gum powder No Yes No Yes No No Yes Yes Yes Impact resistance 100 163 69 106 56 75 81 31 38

[0097] The roof covering elements according to the invention E1 and E2 are to be compared respectively to the comparative roof covering elements T1 and T2 which are made of the same compositions as the corresponding roof covering elements according to the invention, but differ from them by the heating temperature of the mold (150°C for the roof covering elements according to the invention, 30°C for the comparative roof covering elements). Similarly, the roof covering element according to the invention E3 (shaped in a mold heated to 150°C) and to be compared to the comparative roof covering elements T3 and T'3, of the same composition, which were shaped in a mold heated respectively to 30°C and 110°C.

[0098] It appears that the roof covering elements according to the invention El, E2 and E3 achieve improved impact resistance compared to their respective comparative roof covering elements, while exhibiting good encapsulation of the rubber powder, unlike the comparative roof covering elements Tl, T2, T3 and T'3 which exhibit free rubber powder.

[0099] The comparative roof covering elements T4 and T'4 were obtained after an injection step in a mold heated to 110°C or less. They exhibit a well-encapsulated rubber powder but insufficient impact resistance.

[0100] It follows that the roofing elements according to the invention do indeed improve impact resistance while presenting an encapsulated rubber powder.

Claims

Demands

1. A roofing element comprising at least one composition A comprising: - a halogenated thermoplastic polymer; - 10% to 40% by mass of at least one rubber powder relative to the total mass of composition A; obtained by a process comprising at least the following steps: a) a manufacturing step of composition A by mixing all the constituents in a mixing unit; b) an injection step of composition A into a mold heated to a temperature above 110°C so as to obtain the roofing element.

2. Roof covering element according to claim 1, characterized in that the halogenated thermoplastic polymer consists of more than 75% by mass, preferably more than 90% by mass, even more preferably 100% by mass of units derived from one or more monomers comprising at least one halogen atom.

3. Roofing element according to claim 2 characterized in that the monomer(s) comprising at least one halogen atom are selected from vinyl tetrafluoride, vinyl fluoride, vinylidene fluoride, ethylene chlorotrifluoride, vinyl chloride, superchlorinated vinyl chloride, vinylidene chloride, and mixtures of these monomers, and more preferably, the monomer comprising at least one halogen atom is vinyl chloride.

4. Roof covering element according to any one of the preceding claims characterized in that the halogenated thermoplastic polymer is present at a mass rate of 45% to 90%, preferably 55% to 90%, relative to the total mass of composition A.

5. Roof covering element according to any one of the preceding claims characterized in that the halogenated thermoplastic polymer has a weight molecular mass Mw of 50,000 to 250,000 g / mol, preferably of 60,000 to 200,000 g / mol, more preferably of 90,000 to 200,000 g / mol.

6. Roof covering element according to any one of the preceding claims characterized in that the rubber powder comprises a vulcanized rubber composition B comprising at least one elastomer and at least one filler Cl.

7. Roof covering element according to claim 6 characterized in that the elastomer is selected from diene elastomers, alone or in mixture.

8. Roof covering element according to claim 6 or claim 7 characterized in that the filler Cl is a reinforcing filler, preferably selected from carbon blacks.

9. Roof covering element according to any one of claims 6 to 8 characterized in that the mass percentage of filler Cl is between 5% and 80%, preferably between 10% and 60%, most preferably between 15% and 40% by mass relative to the total mass of the rubber powder.

10. Roof covering element according to any one of the preceding claims characterized in that the rubber powder has an average particle size (D50) between 50 and 800pm, preferably between 200 and 600pm.

11. Roof covering element according to any one of the preceding claims, characterized in that the gum powder is present at a mass rate of 10% to 35% by mass relative to the total mass of composition A.

12. Roof covering element according to any one of the preceding claims characterized in that the mold is heated to a temperature ranging from 115°C to 220°C, preferably from 120°C to 200°C, more preferably from 120°C to 180°C.

13. Roof covering element according to any one of the preceding claims in which composition A comprises from 0 to 20%, preferably from 5% to 15% by mass relative to the total mass of composition A of a charge C2.

14. Roof covering element according to claim 13 wherein the filler C2 is an inorganic filler, preferably the filler C2 is selected from clays, bentonites, talcs, chalks, kaolins, graphites or mixtures thereof, more preferably the filler C2 is chalk.

15. A method for manufacturing a roofing element comprising at least the following steps: a) a manufacturing step of a composition A by mixing in a mixing unit all the constituents of composition A which includes at least one halogenated thermoplastic polymer and 10% to 40% by mass, relative to the total mass of composition A, of at least a dusting of gum; b) a step of injecting composition A into a mold heated to a temperature above 110°C so as to obtain the roof covering element.