Roof covering element comprising at least one composition comprising a halogenated thermoplastic polymer and a gum powder

Abstract

Roofing element comprising at least one composition comprising at least one halogenated thermoplastic polymer and at least one gum powder The present invention relates to a roofing element, such as a slate, comprising at least one composition comprising: a) at least one halogenated thermoplastic polymer; b) from 10% to 40% by mass of at least one gum powder relative to the total mass of the composition.

Description

Title of the invention: Roof covering element comprising at least one composition comprising a halogenated thermoplastic polymer and a gum powder

[0001] The present invention relates to roof covering elements, such as a slate, and more particularly to roof covering elements comprising a composition comprising a halogenated thermoplastic polymer and a gum powder. Technical field

[0002] In the construction of structures, especially buildings, the roof of the structure must be able to protect the interior of the structure from the external environment, but also provide a desired aesthetic appearance. The roof of the structure must therefore be made of covering elements having, 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 strength properties and their aesthetic appearance is not necessarily pleasing. In addition, there is still a need to improve the impact resistance of roof covering elements, in particular to improve their lifespan in the event of adverse weather conditions such as hail.

[0004] To overcome these drawbacks, the Applicant has discovered, surprisingly and at the cost of significant research efforts, that a roof covering element which comprises a particular composition, containing a halogenated thermoplastic polymer and a rubber powder, and which has a certain level of anisotropy makes it possible to obtain advantageous properties, in particular in terms of impact resistance of the roofs.

[0005] The present invention therefore has as its first subject a roof covering element comprising at least one composition A comprising:

[0006] a) a halogenated thermoplastic polymer;

[0007] b) from 10% to 40% by mass of at least one gum powder relative to the total mass of composition A;

[0008] the roof covering element having an anisotropy, measured in accordance with the "Anisotropy Measurement" section of the description, greater than 10%.

[0009] Another subject of the invention is a roof covering element according to the invention capable of being obtained by a method comprising at least the following steps:

[0010] a) a step of manufacturing composition A by mixing all of the constituents in a mixing unit;

[0011] b) an extrusion step fed at least with the composition A obtained in step a) in an extrusion machine Vb so as to obtain an extruded strip;

[0012] c) a step of cutting the extruded strip obtained at the end of step b) so as to obtain the roof covering element.

[0013] The roof covering element according to the invention makes it possible to obtain advantageous properties, particularly in terms of impact resistance.

[0014] A roof covering element having a higher impact resistance makes it possible to increase the lifespan of the roof which contains it. Indeed, in the event of hail falling for example, a roofing element having a higher impact resistance will not break, or will crack later, so that it will be necessary to remove and replace the roof covering elements less frequently, resulting in savings in labor time, material cost and quantity of material, with a positive environmental impact.

[0015] Other characteristics and advantages of the invention will appear more clearly on reading the description and examples which follow. Statement of the invention

[0016] 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 (i.e., limits 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 up to b (i.e., including the strict limits a and b).

[0017] The expression “at least one” is equivalent to the expression “one or more”.

[0018] The compounds mentioned in the description may be of fossil or bio-sourced origin. 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.

[0019] Furthermore, the compounds mentioned in the description may be derived from recycling. For example, a material, such as gum powder, may come from used tires or more generally from used materials. Another material, such as polyvinyl chloride, may come from used products, for example those from carpentry, shutters, pipes, etc.

[0020] According to a first aspect, the invention relates 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 gum powder relative to the total mass of composition A; the roof covering element having an anisotropy, measured in accordance with the section “Anisotropy measurement”, greater than 10%.

[0021] Preferably, the halogenated thermoplastic polymer of the roof covering element is 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. More preferably, the monomer(s) 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.

[0022] Advantageously, the halogenated thermoplastic polymer is present at a mass content ranging from 45% to 90%, preferably from 55% to 80% relative to the total mass of composition A.

[0023] Advantageously, the halogenated thermoplastic polymer has a molecular mass by weight Mw ranging from 50,000 to 250,000 g / mol, preferably from 60,000 to 200,000 g / mol.

[0024] Preferably, the gum crumb comprises a vulcanized rubber composition B comprising at least one elastomer and at least one filler Cl. Preferably, the elastomer is chosen from diene elastomers, alone or as a mixture. Advantageously, the filler Cl is a reinforcing filler, preferably chosen from carbon blacks. And, preferably, the mass content of filler Cl is between 5% and 80%, preferably between 10% and 60%, very preferably between 15% and 40% by mass relative to the total mass of the gum crumb.

[0025] Advantageously, the gum powder has an average particle size (D50) of between 50 and 800 pm, preferably between 200 and 600 pm.

[0026] Advantageously, the gum powder is present at a mass rate ranging from 10% to 35% by mass relative to the total mass of composition A.

[0027] Preferably, the roof covering element has an anisotropy, measured in accordance with the section “Anisotropy measurement”, greater than 15%.

[0028] Preferably, composition A of the roof covering element 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, filler C2 is an inorganic filler, preferably a chalk.

[0029] According to a particularly preferred embodiment, the roof covering element is obtained by a method comprising at least the following steps: a) a step of manufacturing composition A by mixing all of the constituents in a mixing unit, such as an extrusion machine Va or a mixer; b) an extrusion step fed at least with the composition A obtained in step a) in an extrusion machine Vb so as to obtain an extruded strip; c) a step of cutting the extruded strip obtained at the end of step b) so as to obtain the roof covering element. Halogenated thermoplastic polymer

[0030] As indicated previously, the roof covering element according to the invention comprises at least one composition A comprising a halogenated thermoplastic polymer.

[0031] For the purposes of the present invention, the term 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 ranging from 80°C to 250°C, more preferably ranging from 80°C to 200°C, and in particular ranging from 80°C to 180°C.

[0032] 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 is taken into account for the above definition and not the glass transition temperature.

[0033] It is clear that a thermoplastic polymer within the meaning of the present invention is different from a thermoplastic elastomer.

[0034] For the purposes of the present invention, the term 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.

[0035] By average molecular mass of a halogenated thermoplastic polymer, we preferably mean the weight average molecular mass (Mw).

[0036] Preferably, the halogenated thermoplastic polymer(s) consist 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.

[0037] Preferably, the monomer(s) 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.

[0038] Advantageously, said halogenated thermoplastic polymer(s) are present at a mass content ranging from 45% to 90% by mass, preferably from 55% to 80% by mass relative to the total mass of composition A.

[0039] Said composition A may optionally comprise one or more thermoplastic polymers other than the halogenated thermoplastic polymers described above.

[0040] Examples of such polymers may include copolymers of acrylonitrile, butadiene and styrene (ABS copolymers), copolymers of ethylene and vinyl acetate (EVA), and mixtures thereof.

[0041] When they are present in composition A, the non-halogenated thermoplastic polymers preferably represent a mass content of less than or equal to 30% by mass, more preferably from 0 to 15% by mass relative to the total mass of composition A.

[0042] More preferably, composition A comprises as thermoplastic polymer only one or more halogenated thermoplastic polymers according to the invention as described above.

[0043] Advantageously, said halogenated thermoplastic polymer has a weight-average molecular mass Mw ranging from 50,000 to 250,000 g / mol, preferably from 60,000 to 200,000 g / mol. Gum powder

[0044] As indicated previously, composition A comprises from 10% to 40% by mass of at least one gum powder relative to the total mass of composition A.

[0045] Gum powders may be commercially available.

[0046] It is recalled that gum powders are generally presented in the form of granules (or aggregates), possibly formed into a rubber slab. Most often, rubber crumbs are a product of material recycling: they come from grinding, in particular micronization, of cooked rubber compositions already used for a first application, for example as tire curing membranes (as in document US6730732) or as tires that have reached the end of their life (as in document KR100943526). Any method or process that does not degrade the rubber during grinding may be suitable as a method of grinding rubber compositions. For example, a method of grinding in the presence of water such as those described in documents US4374573, US4714201, US5238194 and US5411215 may be chosen: such a method method allows the temperature of the gum to be kept at a sufficiently low level to avoid reversion, i.e. the degradation of the rubber crosslinking network. A cryogenic grinding method can also be used. Commercial equipment such as the CUM150 grinders from Netzsch or CW250 from Alpine can be used. Depending on the object size distribution obtained, the gum crumb obtained by the processes mentioned can undergo an additional sieving step in order to control this distribution. Sieving can be carried out by different technologies (vibration, centrifugation, suction) known to those skilled in the art. The gum crumbs resulting from the grinding process are generally in the form of microparticles.By "microparticles" we mean particles which have a size, namely their diameter in the case of spherical particles or their largest dimension in the case of anisotropic particles, of a few tens or hundreds of microns.

[0047] Preferably, the gum powder comprises a vulcanized rubber composition B comprising at least one elastomer and at least one filler CL.

[0048] The elastomer can be chosen from diene elastomers, alone or as a mixture.

[0049] By filler is meant 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 reinforce 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 blend of these two types of filler.

[0050] According to a preferred embodiment of the invention, the gum powder comprises as filler C1 a reinforcing filler chosen from carbon blacks.

[0051] According to a more preferred embodiment of the invention, the reinforcing filler consists of a carbon black or a mixture of carbon blacks.

[0052] Suitable carbon blacks are all carbon blacks, in particular blacks of the HAF, ISAF, SAF, FF, FEF, GPF and SRF type conventionally used in rubber compositions for tires (so-called tire grade blacks).

[0053] 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.

[0054] The gum powder may contain all the other usual additives that are included in a rubber composition. Among these usual additives, mention may be made of vulcanization additives, non-reinforcing fillers, such as chalk or kaolin, and protective agents. These additives may be found in the gum powder also in the form of residue or derivative, since they may have reacted during the manufacturing or crosslinking stages of the rubber composition that the gum crumb contains, or they may have evolved during use in the case of gum crumb from an end-of-life product.

[0055] It is also known that these gum powders can undergo a treatment in order to modify them. This treatment can consist of a chemical modification of functionalization or devulcanization. It can also be a thermomechanical, thermochemical, biological treatment, etc.

[0056] According to a first preferred embodiment of the invention, it is possible to use a gum powder which has not undergone any modification by thermal and / or mechanical, and / or biological and / or chemical treatment.

[0057] Preferably also according to this first embodiment of the invention, the gum powder has an average particle size (D50) of between 50 and 800 pm, preferably between 200 and 600 pm.

[0058] 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.

[0059] Advantageously, the gum powder is present at a mass rate ranging from 10% to 35% by mass relative to the total mass of composition A. Other possible additives

[0060] Composition A according to the invention optionally also comprises various additives, such as for example 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 plasticizing agents, lubricants, mineral powder, etc.

[0061] 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, and even more preferably a chalk.

[0062] According to a preferred embodiment of the invention, composition A further comprises at least one additive, preferably chosen from pigments, such as carbon black, mineral powders and mixtures thereof.

[0063] Advantageously, the additive is present at a mass rate ranging from 0.2% to 20% by mass relative to the total mass of composition A. Preparation of the compositions

[0064] Composition A useful for the purposes of the invention can be obtained by mixing all of its constituents during a step a) in a mixing unit usually used for producing compositions comprising a halogenated thermoplastic polymer.

[0065] According to a first embodiment of the invention, this step a) comprises two phases. The first, called “dry tank mixing” (also called “dry blend”), 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) then continuing the mixing and ensuring cooling in a cold tank (room temperature). The second phase consists of introducing the mixture obtained at the end of the first phase into an extrusion machine Va heated between 130 and 200°C and allows a rod to be obtained at the die outlet which is then cooled and granulated to provide granules of composition A.

[0066] 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, into the hot tank; or during the second phase, into the feed hopper of the extrusion machine Va.

[0067] 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.

[0068] According to another embodiment of the invention, all of the constituents of composition A are introduced during a single mixing-extrusion phase, in an extrusion machine Va. 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 gum powder and the various additives are introduced into the feed hopper of the extrusion machine Va. 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.

[0069] According to another embodiment of the invention, the different constituents of composition A are introduced successively into an internal mixer of the Haake type or into a calender heated between 130°C and 190°C. The mixing is carried out for a period of 1 min to 5 min. Manufacture of roof covering elements

[0070] A roof covering element comprising a composition A could be obtained at the end of a compression molding step of the composition A obtained from step a) described above at a temperature between 160°C and 190°C for a period of 5 to 15 minutes so as to obtain a roof covering element with a width between 200 and 400 mm, a length between 300 and 800 mm and a thickness between 2 and 5 mm.

[0071] According to a preferred embodiment of the invention, the roof covering element according to the invention can be obtained following: - of a step b) of extrusion fed at least with the composition A obtained in step a) described previously in an extrusion machine Vb heated between 130°C and 200°C so as to obtain an extruded strip - followed by a step c) of cutting the extruded strip obtained in step b) so as to obtain the roof covering element according to the invention.

[0072] The extruded strip obtained at the end of step b) typically has a width, measured along the Y direction perpendicular to the extrusion direction X of step b), of between 200 and 400 mm and a thickness of between 2 and 5 mm. It is then cut, during step c), in the transverse direction, that is to say along the Y direction, at regular length intervals along the X direction, so as to obtain a roof covering element with a width of between 200 and 400 mm, a length of between L1 and L2 mm and a thickness of between 2 and 5 mm.

[0073] The Applicant has discovered that this embodiment of the invention is favorable to obtaining a sufficient level of anisotropy to achieve good impact resistance performance. Anisotropy

[0074] The roof covering element according to the invention has an anisotropy greater than 10%. Anisotropy is understood to mean the relative difference between the rigidity of the roof covering element in a direction X (for example, in the case of a roof covering element obtained at the end of steps a), b) and c) as described above, the direction X may be the direction of extrusion of step b) of this roof covering element) and the rigidity of the roof covering element in the direction Y perpendicular to this direction X obtained by the formula:

[0075] A% = IEX - EyI / Ex

[0076] with: - Ex the secant modulus at 1% elongation of the roof covering element in the X direction, - Ey the secant modulus at 1% elongation of the roof covering element in the Y direction.

[0077] The method for measuring anisotropy is described in more detail in the section “Measurement of anisotropy”.

[0078] A substantially zero anisotropy means that the roof covering element has the same stiffness in both the X and Y directions. A strictly positive anisotropy means that the roof covering element is substantially stiffer in one direction (e.g., the extrusion direction of step b)) than in the perpendicular direction.

[0079] The Applicant has discovered, surprisingly, that a higher anisotropy of the roof covering element was associated with better impact resistance of this roof covering element. In particular, when the anisotropy of the roof covering element is greater than 10%, its impact resistance is significantly improved compared to that of a roof covering element having an anisotropy substantially equal to 0. Thus, the roof covering element according to the invention has an anisotropy A% greater than 10%, preferably greater than 15%.

[0080] The Applicant has further noted that the anisotropy levels of the roof covering elements were generally higher when the roof covering elements had been obtained following steps a), b) and c) as described previously.

[0081] The following examples illustrate the invention without, however, limiting it. Examples 1. Characterization methods

[0082] In the examples, the roof covering elements, the halogenated thermoplastic polymers and the gum crumbs are characterized as indicated below. Particle size measurement

[0083] The particle size (notably D50) can be measured by laser granulometry of the “Mastersizer 3000” type from the company Malveme. The measurement is carried out in liquid form, with dilution in alcohol after a preliminary treatment of 1 min 10 sec of ultrasound in order to guarantee the dispersion of the particles. The measurement is carried out in accordance with the ISO-13320-1 standard. Molecular mass measurement

[0084] The SEC (Size Exclusion Chromatography) technique is used to separate macromolecules in solution 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.

[0085] SEC (PS calibration): the SEC is coupled to a refractometer, in this case it gives relative information. From commercial standard products, the different number-average (Mn) and weight-average (Mw) molar masses which characterize the molar mass distribution of the polymer can be determined and the polymolecularity index (Ip = Mw / Mn) calculated via a so-called Moore calibration. There is no particular treatment of the polymer sample 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 pm porosity filter before injection.

[0086] The apparatus used is a "WATERS alliance" chromatographic chain. 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 columns (Mixed BLS) 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.

[0087] The calculated average molar masses are relative to a calibration curve produced from commercial standard polystyrenes “PSS READY CAL-KIT” Anisotropy measurement

[0088] To measure the anisotropy of a roof covering element, specimens are cut from the roof covering element in two directions X and Y perpendicular to each other, each of the directions being parallel to one of the edges of the roof covering. When the roof covering element has been obtained at the end of steps a), b) and c) described in the section “Manufacture of roof covering elements”, the X direction is chosen as the extrusion direction of step b).

[0089] The anisotropy of a roof covering element is calculated according to the formula detailed in the “Anisotropy” section for which the secant moduli Ex and EY are measured during uniaxial traction on the specimens cut respectively in the X and Y directions. A constant uniaxial traction speed is imposed on the specimen, and its elongation and stress are measured. The measurement is carried out using an INSTRON type tensile machine, at a temperature of 23°C, and a relative humidity of 50% (ISO 23529 standard). The conditions for measuring and using the results to determine the elongation and stress are as described in standard NF ISO 37: 2012-03. The stress is determined for an elongation of 0.01 (i.e. 1% elongation, expressed as a percentage) and the secant modulus at 1% elongation is calculated by calculating the ratio of this stress value to the elongation value. Shock resistance measurement

[0090] To measure the impact resistance of a roof covering element, it is held at its two ends in clamping devices and then subjected to the impact of a 500g ball dropped from a given drop height. It is then observed whether the impact (or shock) has caused the appearance of a through crack in the roof covering element, i.e. a crack visible on both the upper and lower faces of the roof covering element. If this is not the case, the same protocol is repeated for a higher drop height. The fracture energy is calculated as the energy of the ball that caused the appearance of the first through crack, given by the formula:

[0091] Eruption = mbiiie x hfall X g

[0092] where: - mbiue is the mass of the ball, i.e. 500g; - hchute is the drop height from which the ball was dropped; - g is the acceleration of gravity, taken equal to 9.8 m / s2.

[0093] The term "impact resistance index" means the value of this breaking energy expressed on a base of 100 relative to the control: the higher the impact resistance index, the better the impact resistance performance. 2. Preparation of roof covering elements

[0094] The compositions are manufactured by introducing all the constituents into a twin-screw type Va extrusion machine for hard PVC, heated to 180°C and operating at a flow rate of 200 to 450 kg / h.

[0095] The comparative roof covering elements T1, T'1, T2, T3 and T4, and the roof covering elements E2, E3 and E4, in accordance with the invention, consist of the compositions prepared on the basis of the constituents as described in Table 1 below, where the contents are expressed in % by mass of the total mass of the composition.

[0096] Then, each of the compositions was shaped according to the method mentioned in Table 1 below so as to obtain a plate, which could thus represent a roof covering element. Two distinct shaping methods were used depending on the roof covering elements: - The M shaping process consists of molding the composition in a compression mold heated to 185°C for 15 min - The E shaping process consists of introducing the composition into a Vb extrusion machine for hard PVC heated to 180°C at a flow rate of 300 kg / h so as to obtain an extruded strip of the desired thickness which is then cut to the desired dimensions.

[0097] It appears that the compositions comprising gum powder shaped by process E make it possible to obtain roof covering elements exhibiting significant anisotropy. This is not the case for the composition not comprising gum powder (roof covering elements T1 and T'1).

[0098] [Tables 1] Composition [% by mass] Tl T'l T2 E2 T3 E3 T4 E4 PVC 1 (1) 100 100 70 70 60 60 PVC 2 (2) 70 70 Gum powder (3) 30 30 30 30 30 30 Chalk (4) 10 10 Anisotropy [%] <5 <5 <5 16 <5 34 <5 18 Shaping SAME SAME 1. Polyvinyl chloride (PVC) polymer “Lacovyl SI 10P” marketed by the company Kemone (Mw > 120,000 g / mol); 2. Polyvinyl chloride (PVC) polymer “Lacovyl SI 10P” marketed by the company Paprec (Mw = 1480,000 g / mol); 3. “MRP Microdyne 830 TR” gum powder marketed by Lehigh Technologies 4. Chalk 239216 marketed by the company Sigma Aldrich 3. Results

[0099] The results are collated in Table 2 below. The roof covering elements according to the invention E2, E3 and E4 are respectively to be compared with the comparative roof covering elements T2, T3 and T4 which are made of the same compositions as the corresponding roof covering elements according to the invention, but differ from them by their level of anisotropy and the nature of the shaping process.

[0100] [Tables2] Performance Tl T'l T2 E2 T3 E3 T4 E4 Impact resistance index 100 100 60 100 29 53 46 64

[0101] It appears that the roof covering elements E2, E3 and E4, in accordance with the invention and in particular having anisotropy levels greater than 10%, have higher impact resistance levels than their isotropic equivalents T2, T3 and T4 comparative. The roof covering elements T1 and T'1, not in accordance with the invention, in particular in that they are made of a composition not comprising rubber powder, have low levels of anisotropy (regardless of the shaping process chosen M or E) and both have the same level of impact resistance.

[0102] As a result, the roofing elements in accordance with the invention make it possible to improve impact resistance.

Claims

Claims

1. Roof covering element comprising at least one composition A comprising: a) a halogenated thermoplastic polymer; b) from 10% to 40% by mass of at least one gum powder relative to the total mass of composition A; the roof covering element having an anisotropy greater than 10%, the anisotropy being measured, as described in the description, using an INSTRON type tensile machine, for an elongation of 1%, at a temperature of 23°C and a relative humidity of 50%, according to standard ISO 23529.

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. Roof covering element according to claim 2 characterized in that the monomer(s) 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.

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 ranging from 45% to 90%, preferably from 55% to 80% 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 molecular mass by weight Mw ranging from 50,000 to 250,000 g / mol, preferably from 60,000 to 200,000 g / mol.

6. Roof covering element according to any one of the preceding claims, characterized in that the powder of gum 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 chosen from diene elastomers, alone or as a mixture.

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

9. Roof covering element according to any one of claims 6 to 8, characterized in that the mass rate of filler Cl is between 5% and 80%, preferably between 10% and 60%, very 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 gum powder has an average particle size (D50) of between 50 and 800 pm, preferably between 200 and 600 pm.

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

12. A roof covering element according to any preceding claim having an anisotropy, measured in accordance with the "Anisotropy Measurement" section of the description, greater than 15%.

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 filler C2.

14. Roof covering element according to claim 13 in which the filler C2 is an inorganic filler, preferably a chalk.

15. Roof covering element according to any one of the preceding claims obtained by a process comprising at least the following steps: a) a step of manufacturing composition A by mixing all of the constituents in a mixing unit; b) an extrusion step fed at least with the composition A obtained in step a) in an extrusion machine Vb so as to obtain an extruded strip; c) a step of cutting the extruded strip obtained at the end of step b) so as to obtain the roof covering element.