Roof covering element comprising at least one composition comprising a halogenated thermoplastic polymer and a crumb rubber

Abstract

The present invention relates to a roofing element, such as a slate tile, comprising at least one composition containing: - at least one halogenated thermoplastic polymer; 10 wt.-% - 40 wt.-% at least one crumb rubber relative to the total weight of the composition, and being obtained by means of a specific method.

Description

[0001] DESCRIPTION

[0002] TITLE: Roof covering element comprising at least one composition comprising a halogenated thermoplastic polymer and a gum powder

[0003] 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.

[0004] TECHNICAL FIELD

[0005] 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 roofing elements that have, in particular, weather-resistant properties.

[0006] 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, particularly to improve their lifespan in the event of adverse weather conditions such as hail.

[0007] To this end, 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 gum powder, obtained by a process comprising in particular a step of injecting the particular composition into a mold heated to high temperature, makes it possible to obtain advantageous properties, in particular in terms of impact resistance of the roofs, while surprisingly improving the encapsulation of the gum powder in the composition.

[0008] By "gum crumb encapsulated in a composition" is meant gum crumb perfectly coated by the composition which contains it; it is then said that there is good encapsulation of the gum crumb in the composition. On the contrary, when at least part of the gum crumb is not coated in the composition, but is flush with the surface of a sample of the composition and could easily be detached by simple friction of the surface, it is referred to as "free gum crumb", or poor encapsulation of the gum crumb in the composition.

[0009] However, at the end of certain manufacturing processes for the roof covering element, the gum powder may not be well encapsulated in the composition, i.e. a significant proportion of free gum powder remains, which easily detaches from the roof covering element and generates dust which is troublesome for handling during installation, for example. The invention makes it possible to overcome this industrial drawback.

[0010] The present invention therefore has as its first subject a roof covering element comprising at least one composition A comprising:

[0011] - a halogenated thermoplastic polymer;

[0012] - from 10% to 40% by mass of at least one gum powder relative to the total mass of composition A; 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) a step of injecting composition A into a mold heated to a temperature above 110°C so as to obtain the roof covering element.

[0013] Another subject of the invention is a method for manufacturing a roof covering element comprising at least the following steps: a) a step of manufacturing a composition A by mixing in a mixing unit all the constituents of composition A which comprises at least one halogenated thermoplastic polymer and from 10% to 40% by mass, relative to the total mass of composition A, of at least one rubber 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.

[0014] 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.

[0015] A roof covering element with higher impact resistance increases the lifespan of the roof that contains it. Indeed, in the event of hail, for example, a roofing element with higher impact resistance will not break, or will crack later, so that roof covering elements will have to be removed and replaced less frequently, resulting in savings in labor time, material costs and quantity, with a positive environmental impact.

[0016] In addition, a roof covering element having better encapsulation of the gum dust in the composition A included in the roof covering element allows easier handling of the roof covering element. Indeed, when transporting or installing the roof covering element comprising a composition A, if gum dust is free from the composition A, it can easily detach from the roof covering element and cause it to slip between the hands of the operator or generate dust in the storage location for example. Thus, a roof covering element not comprising free gum dust offers a definite advantage in terms of industrial efficiency.

[0017] Other characteristics and advantages of the invention will appear more clearly on reading the description and examples which follow.

[0018] STATEMENT OF THE INVENTION

[0019] Any interval of values ​​designated by the expression "between a and b" represents the domain of values ​​from more than a to less than b (i.e., excluding the limits a and b), while any interval of values ​​designated by the expression "from a to b" means the domain of values ​​from a to b (i.e., including the strict limits a and b).

[0020] The expression "at least one" is equivalent to the expression "one or more".

[0021] 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 polymers, plasticizers, fillers, etc.

[0022] 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. According to a first aspect, the invention relates to a roof covering element comprising at least one composition A comprising:

[0023] - a halogenated thermoplastic polymer;

[0024] - from 10% to 40% by mass of at least one gum powder relative to the total mass of composition A; 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) a step of injecting composition A into a mold heated to a temperature above 110°C so as to obtain the roof covering element.

[0025] Preferably, 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. 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.

[0026] Advantageously, the halogenated thermoplastic polymer is present at a mass rate ranging from 45% to 90%, preferably from 55% to 90% relative to the total mass of composition A.

[0027] 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, more preferably from 90,000 to 200,000 g / mol.

[0028] Preferably, the gum crumb comprises a vulcanized rubber composition B comprising at least one elastomer and at least one filler Cl. More 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. 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. Advantageously, the gum crumb has an average particle size (D50) of between 50 and 800 pm, preferably between 200 and 600 pm.

[0029] 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.

[0030] 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.

[0031] 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, filler C2 is an inorganic filler; even more preferably, filler C2 is chosen from clays, bentonites, talcs, chalks, kaolins or graphites or mixtures thereof; preferably filler C2 is a chalk.

[0032] The invention also relates to a method for manufacturing a roof covering element comprising at least the following steps: a) a step of manufacturing a composition A by mixing in a mixing unit all of the constituents of composition A which comprises at least one halogenated thermoplastic polymer and from 10% to 40% by mass, relative to the total mass of composition A, of at least one rubber 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.

[0033] Halogenated thermoplastic polymer

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

[0035] 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.

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

[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 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.

[0039] The average molecular mass of a halogenated thermoplastic polymer is preferably understood to mean the weight-average molecular mass (Mw).

[0040] 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.

[0041] 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.

[0042] Advantageously, said halogenated thermoplastic polymer(s) are present at a mass rate ranging from 45% to 90% by mass, preferably from 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.

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

[0045] When 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. More preferably, composition A comprises as thermoplastic polymer only one or more halogenated thermoplastic polymers according to the invention as described above.

[0046] 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.

[0047] 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 range of Mw particularly concerns halogenated thermoplastic polymers derived from the recycling of used products, typically recycled polyvinyl chlorides, the Mw of which is not necessarily suitable for the injection process. Indeed, during the recycling of halogenated thermoplastic polymers derived from used products, no step is provided to sort or separate halogenated thermoplastic polymers designed for injection processes, which generally have a lower Mw than the others, and those designed, for example, for extrusion processes, which may have a higher Mw.However, a composition comprising at least one of these latter halogenated thermoplastic polymers and from 10% to 40% by mass relative to the mass of the composition of a gum crumb is capable, at the end of a step of injecting said composition into a mold, of having free gum crumb, that is to say not encapsulated in the composition. Thus, one of the advantages of the invention is to make it possible to obtain a roof covering element comprising a halogenated thermoplastic polymer and from 10% to 40% by mass of at least one gum crumb relative to the total mass of the composition not having free gum crumb, even after a step of injecting the composition into a mold under the conditions provided for by the invention.

[0048] Gum powder

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

[0050] Gum powders may be available commercially.

[0051] It is recalled that rubber crumbs are generally 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 for grinding rubber compositions.For example, a grinding method in the presence of water may be chosen, such as those described in documents US4374573, US4714201, US5238194 and US5411215: such a method makes it possible to maintain the temperature of the gum at a sufficiently low level to avoid reversion, i.e. the degradation of the crosslinking network of the gum. A cryogenic grinding method may also be used. Commercial equipment such as the CUM150 grinders from the company Netzsch or CW250 from the company Alpine may be used. Depending on the object size distribution obtained, the gum crumb obtained by the processes cited may undergo an additional sieving step in order to control this distribution. Sieving may 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.

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

[0053] The elastomer can be chosen from diene elastomers, alone or in a mixture.

[0054] By filler is meant any type of filler, well known to those skilled in the art. Preferably, the filler C1 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. According to a preferred embodiment of the invention, the gum crumb comprises, as filler C1, a reinforcing filler chosen from carbon blacks.

[0055] According to a more preferred embodiment of the invention, the reinforcing filler consists of a carbon black or a mixture of carbon blacks.

[0056] Suitable carbon blacks are all carbon blacks, including HAF, ISAF, SAF, FF, FEF, GPF and SRF types conventionally used in rubber compounds for tires (so-called tire grade blacks).

[0057] 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.

[0058] Gum crumb may contain all other usual additives that are part of a rubber composition. These usual additives include vulcanization additives, non-reinforcing fillers such as chalk, kaolin, and protective agents. These additives may also be found in the gum crumb 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 end-of-life products.

[0059] It is also known that these gum powders can undergo treatment to modify them. This treatment can consist of a chemical modification of functionalization or devulcanization. It can also be a thermomechanical, thermochemical, biological treatment...

[0060] 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.

[0061] Preferably also according to this first embodiment of the invention, the gum powder has an average particle size (D50) of between 50 and 800 mm, preferably between 200 and 600 mm.

[0062] 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. 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.

[0063] Other possible additives

[0064] 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.

[0065] 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. Inorganic fillers that may be suitable for C2 are, preferably, clays, bentonites, talcs, chalks, kaolins, graphites or mixtures thereof. More preferably, filler C2 is a chalk.

[0066] 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.

[0067] 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.

[0068] Preparation of the compositions

[0069] 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.

[0070] 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 heated to 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.

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

[0072] Where the halogenated thermoplastic polymer is a recycled halogenated thermoplastic polymer, it may be introduced either in the first phase or in the second phase.

[0073] 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. 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 crumb and the various additives are introduced into the feed hopper 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 different 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 min to 5 min.

[0075] Manufacture of roof covering elements

[0076] A roof covering element according to the invention can be obtained at the end of a step of injecting the 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 ranging from 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. It is important that the mold is initially heated to a temperature substantially above the glass transition temperature (according to the definition given above) 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 a polyvinyl chloride whose glass transition temperature would be 95°C, and there is a risk of obtaining a roof covering element with free rubber powder.

[0077] Advantageously, 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 temperature ranges of the mold make it possible to improve the encapsulation of the gum 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 roof covering element in accordance with the invention, i.e. a method comprising at least the following steps: a) a step of manufacturing composition A by mixing in a mixing unit all the constituents of composition A (as described in the section “Preparation of the compositions”); b) a step of injecting composition A obtained in step a) into a mold heated to a temperature above 110°C so as to obtain the roof covering element in accordance with the invention; composition A comprising, as described previously, at least one halogenated thermoplastic polymer and from 10% to 40% by mass, relative to the total mass of composition A, of at least one gum powder.

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

[0080] EXAMPLES

[0081] In the examples, the roof covering elements, halogenated thermoplastic polymers and gum crumbs are characterized as follows. 1. Characterization Methods a. Particle Size Measurement

[0082] Particle size (especially D50) can be measured by laser granulometry of the "mastersizer 3000" type from Malverne. The measurement is carried out in liquid form, with dilution in alcohol after a preliminary treatment of 1 min 10 sec of ultrasound to ensure particle dispersion. The measurement is carried out in accordance with ISO-13320-1. b. Molecular mass measurement

[0083] 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.

[0084] SEC (PS calibration): SEC is coupled with a refractometer, in this case it provides relative information. From commercial standard products, the different number-average (Mn) and weight-average (Mw) molar masses that characterize the molar mass distribution of the polymer can be determined and the polydispersity 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.

[0085] The equipment 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.

[0086] The calculated average molar masses are relative to a calibration curve produced from commercial standard polystyrenes “PSS READY CAL-KIT”. c. Characterization of the encapsulation of the gum powder

[0087] The characterization of the encapsulation of the gum crumb is essentially done visually: if we observe flush gum crumb, which protrudes from the surface of the roof covering element and can detach from it when the hand passes over it, then we consider that the gum crumb is free and is not encapsulated. If, on the contrary, the surface of the roof covering element is smooth, without flush gum crumb that detaches from it, then the gum crumb is well encapsulated.

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

[0089] To measure the impact resistance of a roof covering element, it is held at both 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: Rupture — mbille X hchute X g where:

[0090] - mbiiie is the mass of the ball, i.e. 500g;

[0091] - hchute is the drop height from which the ball was dropped;

[0092] - g is the acceleration of gravity, taken equal to 9.8 m / s 2

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

[0094] 2. Preparation of roof covering elements

[0095] The compositions are manufactured by introducing all the constituents into a twin-screw extrusion machine for hard PVC, heated to 180°C and operating at a flow rate of 200 to 450 kg / h.

[0096] The comparative roof covering elements T1, T2, T3, T'3, T4 and T'4, and the roof covering elements E1, E2 and E3, 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.

[0097] Then, each of the compositions is injected into a mold heated to the temperature indicated in table 1 below in order to obtain a plate, which can thus represent a roof covering element.

[0098] [Table 1]

[0099] (1) Polyvinyl chloride (PVC) polymer “Evervinyl EXTRI G0M6” marketed by the company Paprec (Mw = 152,065 g / mol);

[0100] (2) Polyvinyl chloride (PVC) polymer “Lacovyl S-RB S071 / S” marketed by the company Kem One (Mw > 130,000 g / mol?);

[0101] (3) Polyvinyl chloride (PVC) polymer “Vinika VRIN713” marketed by the company Vinika (Mw = 75,786 g / mol);

[0102] (4) “MRP Microdyne 830 TR” gum powder marketed by Lehigh Technologies

[0103] 3. Results

[0104] The results are collected in Table 2 below.

[0105] [Table 2]

[0106] The roof covering elements according to the invention E1 and E2 are to be compared respectively with 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) is to be compared with the comparative roof covering elements T3 and T' 3, of the same composition, which were shaped in a mold heated to 30°C and 110°C respectively.

[0107] It appears that the roof covering elements according to the invention E1, E2 and E3 achieve improved impact resistance compared to their respective comparative roof covering elements, while exhibiting good encapsulation of the rubber crumb, unlike the comparative roof covering elements T1, T2, T3 and T'3 which exhibit free rubber crumb. 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 well-encapsulated rubber crumb but insufficient impact resistance.

[0108] As a result, the roofing elements in accordance with the invention make it possible to improve impact resistance while having encapsulated rubber powder.

Claims

CLAIMS 1- 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; 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) a step of injecting composition A into a mold heated to a temperature above 110°C so as to obtain the roof covering 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- 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 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 molecular mass by weight 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. 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 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 charge 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 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- 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 filler C2. 14- Roof covering element according to claim 13 in which the filler C2 is an inorganic filler, preferably the filler C2 is chosen from clays, bentonites, talcs, chalks, kaolins, graphites or their mixtures, more preferably the filler C2 is a chalk. 15- Method for manufacturing a roof covering element comprising at least the following steps: a) a step of manufacturing a composition A by mixing in a mixing unit all the constituents of composition A which comprises at least one halogenated thermoplastic polymer and from 10% to 40% by mass, relative to the total mass of composition A, of at least one rubber 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.

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