MXPA99007628A - Polymer stabilized bitumen granulate - Google Patents

Abstract

Granular asphalt compositions contain bitumen in an amount from about 45%to about 80%by wt. and crystalline and/or rigid polymer in an amount from about 15%to about 50%by wt., which composition has been stabilized or incorporated into the bitumen with synthetic rubber in an amount from about 3%to about 25%by wt. The bitumen used in the compositions may have a wide penetration range from soft to hard base and is the major component of the composition up to about 80%by wt. The resulting compositions can be granulated and the granules stored over a considerable length of time without sticking together. The granules may be readily and rapidly dispersed in bitumen to dilute the polymer content while the polymer remains stably displaced in the bitumen. The granules are useful in varied applications, such as in paving, roofing and other construction industries, and may be transported to sites for ready use thereat.

Description

STABBYED BITUMEN GRANULATE COMBINED WITH POLYMER FIELD OF THE INVENTION The present invention relates to compositions of bitumen granules stabilized with polymer and with processes for their preparation, as well as the commercial application thereof.

BACKGROUND OF THE INVENTION Asphalt is a black, sticky, cementitious material that varies widely in consistency from a hard, elastic consistency to a "solid" and smooth consistency at normal room temperature. Polymers, such as rubbers or plastics, are added to improve the performance of bitumen without changing the traditional means of storage and transportation. Both polymer-modified asphalts for most applications, for example, in the preparation of bitumen compositions for paving, roofing and industrial applications, have been supplied from the plant in a hot liquid form and stored hot , ready to use, inside isolated tanks. Within many years the asphalt industry has made considerable efforts, but limited success has been obtained in the production of asphalt granulate that can be stored at normal room temperature without losing its free flow property. German Patent DE-PS 29 33 339 describes the preparation of a powdery bitumen concentrate which is applied by spraying hot liquid bitumen on about 10% to 80% by weight of silica, so that the silica is completely covered. with the bitumen or asphalt. Asphalt coated composites tend, however, to stick together during storage, due to static pressure forces. In U.S. Patent No. 5,382,348 to Karl-Hans Muller, a process is proposed for producing a free-flowing bitumen granulate by atomizing an asphalt cement with a hot liquid base, and at the same time introducing this cement together with a stream of cooling air, a filler, for example silica, which serves as a spraying and separating agent and which forms a coating of the bitumen droplets. The granulation compositions of this process are limited to a type of hard bitumen, such as a hard base. However, the composition is stored at high temperatures, the bitumen migrates to the surface and thus the free flow properties are impaired. Although the addition of polymers (particularly rigid plastics) to asphalt cement at an increasing loading level can be expected to improve the asphalt granulation ability, poor miscibility or incompatibility of the two components makes it difficult to provide a composition that can be pelleted. unless the bitumen becomes a minor component and functions as an extender in the polymer-based material. The granular composition resulting from these polymer-based materials spread with asphalt would tend to be sticky due to the migration of the asphalt to the surface of the mixture and to the static pressures during storage. However, the problem arises when preparing a bitumen granulate stabilized with polymer that can be stored in a considerable period of time without losing its properties of free flow and that can be easily diluted in the bitumen while retaining the improved performance of the standards of the modification of the polymer.

SUMMARY OF THE INVENTION According to the present invention, novel bitumen compositions of high concentration of dispersed polymer are provided which are capable of being pelleted or granulated and wherein the pellets or granules formed retain their free flowing condition. Further, the pellets or granules can be easily diluted with the bitumen at a lower polymer loading level while the dispersed polymer is stabilized and is capable of imparting performance improvement properties in the resulting bitumen compositions. In accordance with the present invention, a bitumen composition suitable for granulation or pelletizing was provided by forming free flowing stable pellets or granules, comprising about 10 to about 50% by weight of at least one crystalline and / or rigid polymer that has been stabilized or incorporated into the bitumen using at least one rubber, in an amount of about 3 to about 25% by weight. The crystalline or rigid polymers are preferably present in an amount of about 15 to about 30% by weight, while the rubber or rubbers are present in an amount of about 5 to about 15% by weight. Bitumen is the main component of the composition and may be present in an amount ranging from about 45% to about 85%, preferably about 50 and about 75% by weight. The bitumen composition retains the ability to improve performance as a polymer modified asphalt, resists phase separation of the polymer P882 during dilution with the asphalt and acts as a binder after the composition is melted. The bitumen used here can have a wide range of penetration, from a soft base to a hard base. Bitumen is the main component of the composition from which the pellets or granules are formed and may be present in an amount of up to about 85% by weight of the composition. The bitumen compositions of the invention exhibit considerable homogeneity and storage stability during dilution with the bitumen at a low polymer concentration and the pellets that are formed are free flowing and can be dispersed quickly and easily in the bitumen, for use. Further, from the pelletization or granulation of the compositions, any other type of configurations and shapes may be provided, for example, bricks, discs and sheets of bitumen composition.

GENERAL DESCRIPTION OF THE INVENTION The term "bitumen" which is used herein refers to a class of black or dark colored cementitious substances (solid, semi-solid or viscous), natural or manufactured, composed mainly of high molecular weight hydrocarbons. of which asphalt, tar, fish and asphaltites are examples P882 typical. The term "asphalt" used herein refers to a cementitious, dark, brown to black, solid or semi-solid material in its consistency, which is the predominant constituent of bitumens occurring in nature, as such, or they are obtained as a residue in the refinement of petroleum. Providing high levels of dispersed polymer phase, as achieved here, can be accomplished using a variety of different stabilization systems for the dispersed polymer phases, as discussed in detail below. These stabilization systems include spherical stabilization, depletion stabilization and domain stabilization. In U.S. Patent Nos. 5,280,064, 5,494,966 and 5,708,061, so as in copending U.S. Patent Application No. 08 / 563,600 filed on November 28, 1995 and corresponding to WO 93/07219 wherein the inventor of the present was named as inventor, the spherical stabilization of crystalline polyethylene and other crystalline polyolefins in bitumen is described, by the formation of chemical bonds between functionalized polyethylene, as an anchor polymer, and functionalized polybutadiene, as a stabilizing entity, to provide stable dispersions of polyethylene in bitumen. The stabilization Elastic spherical p882 described herein may be employed to provide the compositions of the present invention. According to the teachings of WO 94/22957, which is incorporated herein by reference and wherein the inventor is named as one of the inventors, one or more additional polymers may be incorporated within the spherical stabilized compositions of the aforementioned patents. These additional polymers are generally copolymers and may contain residual unsaturations. These additional copolymers are usually incompatible with the bitumen and therefore normally separate or coalesce quickly when the agitation of the composition is stopped. However, according to the invention of WO 94/22957, when these copolymers are incorporated in the stabilized polyolefin compositions of WO 93/07219, they are stabilized and resist separation of the bitumen. Some copolymers that can be used here are somewhat compatible with bitumen or can be made compatible by suitable processing. The presence of the polyolefin phase dispersed in the bitumen compositions comprising these materials, in the worst case does not destabilize these materials and can often improve this stability. The manner in which the additional copolymers are stabilized in the composition of WO 94/22957 depends on the nature of the polymer employed and may include entanglement, physical trapping, chemical cross-linking or combinations of two or more mechanisms. Copolymers which may be incorporated in the bitumen compositions according to the invention include elastomeric copolymers, including: styrene copolymer, for example styrene-butadiene rubber (SBR), styrene-butadiene-styrene block copolymers (SBS) ), styrene-ethylene-butadiene-styrene block copolymers (SEBS) and styrene-isoprene-styrene block copolymers (SIS); olefinic copolymers, for example, polypropylene copolymers, ethylene-vinyl acetate copolymers (EVA), ethylene methacrylate copolymers (EMA) and ethylene, propylene and diene copolymers (EPD). Other polymers, for example nitrile-butadiene rubber (NBR), polyvinylchloride (PVC), polyisobutene and polybutadiene (PB). Mixtures of two or more of these polymers can be incorporated into the bitumen compositions together with the polyolefin. The compositions of WO 94/22957 may not necessarily employ components, for example process oils, which make the polymers more compatible with the bitumen. In general, the selection of the copolymer to be incorporated in the bitumen of the composition of WO 94/22957 is influenced by the following parameters, as well as possibly others: the chemical composition of the asphalt the molecular weight of the polymer or polymers the strength of shear applied during the mixing of the components - the ratio of constituents of the copolymer, for example, the molar ratio E: VA in EVA. The polymeric materials may be present in the bitumen composition in the form of particle dispersions, strand-like dispersions, solutions and combinations in which the polymer or copolymer is stabilized against separation. In the document, the disclosure of which is incorporated herein by reference, wherein the inventor of the present is named as an inventor, is described the stabilization of polyolefins in bitumen by the mechanism of stabilization by exhaustion, with the use of a material macromolecular to which the bitumen phase has been reduced and the dispersed polyolefin has been stabilized against separation, without the need to form chemical bonds or physical bonds between the macromolecular material and the particulate polyolefin. The macromolecular material dissolved in the bitumen phase provides a potential energy barrier against the coalescence and flocculation of the dispersed polymer phase to maintain a stable dispersion of the particulate polyolefin phase. In this case, there is no need for a functionalized polyolefin to impart stability. The macromolecules used in the depletion stabilization of the dispersion of polyolefin particles in the bitumen can be any desired material, including unsaturated polymers or copolymers which are elastomeric, for example, a polybutadiene, a styrene-butadiene-styrene block copolymer ( SBS), styrene-butadiene random copolymers (SBR) or other polybutadiene-based copolymers, which may be provided in the form of de-vulcanized rubber or dissociated rubber vulcan. Other macromolecular materials that may be employed include natural rubber, polyisoprene and nitrile-butadiene rubbers. These macromolecules can have a molecular weight of from about 5,000 to about 300,000 or more, as long as the molecules are soluble or can be completely digested in the bitumen. The polyolefins crystallized with the present invention can be polyethylene (PE), polypropylene (PP), P882 virgin or recycled, a mixture of PE / PP and / or polyethylene functionalized with maleic anhydride in the case of spherical stabilization, which can be either high or low density and / or high or low melt flow. The percentage of the functionalized polyethylene based on: the total amount of the crystalline polyolefin polymers that are used in general is in the range of from about 3 to about 100% by weight, preferably from about 10 to about 20% by weight, based on the total amount of crystalline polymers used. The functionalized polyethylene is the anchor polymer in the spherical stabilization systems, which functions as a receiver structure to be combined with the non-functionalized polyethylene with which it is mixed. An effective dispersion temperature for polyethylene or other polyolefins is obtained at least about 10 ° C above the melting temperature of the polyolefin being dispersed, depending on factors such as the molecular weight of the polymer, the viscosity of the matrix and shear force during mixing. Therefore, a polyethylene grade having a melting point of 130 ° C to 135 ° C can be dispersed at a temperature of approximately greater than 140 ° C. Low density, low density polyethylenes P882 linear and high density that are normally found can therefore be dispersed and stabilized by a stabilizer system in the present invention, including spherical stabilization and depletion stabilization. Most polyethylenes can therefore be dispersed and stabilized by a stabilizer in the present invention. The majority of the polyethylene used in consumer products has a melting temperature in the acceptable range and polyethylene blends, for example those obtained by peelling, hojing or spraying the recycled material, are suitable for the dispersion of bitumens and can be stabilized according to the present invention. The synthetic rubbers that serve as co-stabilizers with the functionalized polyethylene for the dispersion of the crystalline polymers in the bitumen, in spherical stabilization, can be: rubber diene, which can have a wide molecular weight range, such as that described above in the United States patents, for example polybutadiene (BR), styrene-diene rubbers (including SBS, SB and SBR) or treated diene rubber vulcanate, for example de-vulcanized rubber, tire rubber produced according to the procedure of WO 94/14896, combined with a small proportion of amine-functionalized diene-based polymer, for example P882 poly (butadiene-co-acrylonitride) functionalized with amine, from about 3% to about 35% by weight, preferably from about 5 to about 20% by weight, based on the total amount of the rubber stabilizer component. Two rubbers used as co-stabilizers, mainly non-functionalized and functionalized, are crosslinked and compatibilized in situ within the bitumen, which can be carried out in the presence of sulfur or another suitable reagent. In WO 94/14896 whose disclosure is incorporated herein by reference, wherein the inventor is named as an inventor, a method for devulcanizing rubber and for forming bitumen compositions containing the devulcanized material is disclosed. The smoothed and swollen rubber particles are subjected to a high shear to more effectively break the rubber vulcanite network, which is then incorporated into the bitumen. In WO 97/30121, the disclosure of which is incorporated herein by reference and in which the inventor of the present is named as one of the inventors, it is described to provide a composition of an elastomeric triblock copolymer comprising at least two segments of polystyrene and stabilizes and compatibilizes in bitumen. A particulate and dispersed polymer phase that P882 consists of polystyrene or rigid styrene-based copolymers miscible in the molten state with polystyrene, is dispersed in the bitumen phase and is normally incompatible with the bitumen phase and is stabilized against separation of the bitumen phase by the copolymer of elastomeric triblock by domain stabilization. The bitumen-soluble elastomeric copolymer containing the styrene segment serves a double function, namely (1) it effects a uniform dispersion of the polystyrene-based rigid polymers, normally incompatible with the bitumen and (2) it provides a styrene domain as a receiving unit for the stabilization of the rigid polymer based on dispersed polystyrene, against the separation of the bitumen. The polystyrene domains that are dispersed through the bitumen due to the stabilization or compatibilization of the elastomeric triblock copolymer in the bitumen, allow rigid, normally incompatible polystyrene macromolecules to be incorporated into the bitumen by receiving the polystyrene particles within the polystyrene. the domains. The domains in the continuous phase of the hulified bitumen become larger once the rigid polystyrene macromolecules are mixed and increase in dimension by increasing the levels of the P882 rigid polystyrene dispersed. The domain of the elastomeric styrene polymer, which is easily dispersed or stabilized in the bitumen, is provided by an elastomeric triblock copolymer in which the butadiene rubber segments are compatible or soluble or can be compatibilized or solubilized in the bitumen. The elastomeric triblock copolymers may comprise about 20 to about 80% terminal styrene blocks, preferably about 24 to about 45%. Examples of block copolymers that may be employed include styrene-butadiene-styrene triblock copolymers (SBS) styrene-ethylene / butylene-styrene triblock copolymers (SEBS) and styrene-isoprene-styrene (SIS) block copolymers. These triblock polymers can be used to form stable dispersions of the rigid styrenic polymers in the bitumen. The elastomeric block copolymers that can be used in the composition of the present invention can have a molecular weight (Mn) of between about 30,000 to about 375,000, preferably about 75,000 to about 275,000. The rigid styrenic polymers that are stably dispersed in the bitumen according to the P882 invention can be polystyrene homopolymers, for example polystyrene foam and crystal polystyrene, or they can be graft copolymers and physical mixtures / alloys with various rubbers, or they can be styrene polymer derivatives, for example poly (alpha-methylstyrene), poly (p-tert-butyl styrene) and polychlorostenyl. Rigid styrenic polymers may also comprise rigid copolymers based on styrene, for example, poly (styrene-co-vinylacetate) and poly (styrene-co-vinyl thiophene). The styrenic polymers may be natural or recycled polymers, including blends of styrenic polymers. Triblock copolymers SEBS, SBS or SIS can also be used to disperse and form stable dispersions of other polymers instead of polystyrene, as long as the polymer is miscible with polystyrene in the molten state and therefore the particulates can be received by the polymers. polystyrene domains. One of these polymers is polyphenylene oxide (PPO) which is difficult to disperse in bitumen, but which is miscible with polystyrene in a molten state in any dispersion and can be dispersed and incorporated into the bitumen by the domain effect.

P882 These styrenic polymers can have a molecular weight of between about 40,000 and about 1,400,000 preferably about 100,000 and about 300,000. In addition to the systems of specific stabilization systems employing spherical stabilization, depletion stabilization and domain stabilization, which are discussed in detail above, the present invention also applies to other stabilization systems of rigid or crystalline polymers, in bitumen, using the procedures described here. The incorporation of a chemically reactive mixture of the above-described multi-polymeric components into the bitumen is generally carried out in a two-step reaction process to prepare a polymer-stabilized asphalt composition which is capable of being granulated or processed in any other way to acquire a desired physical form. The process that can be used according to the invention involves: 1) reactively mixing the polymer components in the bitumen; and 2) then chemically incorporating the polymers into the bitumen by increasing addition of a crosslinking agent, for example sulfur, in the mixture. According to the present invention, the polymers P882 crystalline and / or rigid, for example polyethylene and polystyrene, in the granulated composition, are incorporated in situ into the base matrix of the bitumen at an elevated temperature. In the case of polyolefins, the polymer is heated above the crystallization temperature of the polymer used to produce a profusion of dispersed microscopic particles of molten polyolefin. The polyolefin or polyolefins that are stably incorporated into the bitumen matrix do not lose the ability to crystallize once they are cooled below their melting temperature. The small size of the rigid or crystalline polymer particles that are incorporated in the bitumen and the load levels of the rigid or crystalline polymer in the compositions ensure that the compositions have a sufficiently high stiffness and cohesion to be granulated or pelleted and allow their nature granular is stored in a considerably long storage period at ambient temperatures. The compositions that are provided according to the invention can be granulated or pelleted by any conventional or suitable granulation process. Alternatively, the compositions can be processed in any desired physical form.

P882 The ability to produce polymer-modified bitumen, pelletizing and free-flowing bitumen, as is done here, is significant since by providing bitumen in this way, a wider distribution area can be obtained from a manufacturing facility Modified asphalt with polymer, less expensive. The need to isolate tanks to preserve the asphalt in a molten condition from the plant to the site of use is avoided. The pelletized or granulated material, which retains a free flow condition, can be shipped in bulk, to the user, in any convenient form of packaging, for example in bags, boxes or in bulk containers. At the site of use, the pellets can be diluted and then allowed to stand with the molten asphalt under a low shear agitation, providing a polymer modified asphalt wherein the dispersed polymer, usually polyethylene or polystyrene, is stable and capable of imparting characteristics beneficial to bitumen, as a result of elastic stabilization by the techniques described above. Alternatively, the pellets or granules can be mixed directly into a kneading mill of a hot asphalt mixing plant to produce the hot mix of polymer modified asphalt.

P882 Different formulations can be prepared for different final commercial uses, for example, pelleted compositions for use in stone mastic asphalts (SMA) in which cellulosic fibers are added to decrease the asphalt binder leaving the aggregate. The dilution of the pellets with asphalt can be carried out at any desired level of polymer modification of the final composition consistent with the end use contemplated, so that the bitumen granulate compositions provided herein are versatile in their final use while the polymer remains Stably dispersed in the final composition. Providing free-flowing polymer modified bitumen pellets or pellets results in improved capacity production of a polymer-modified asphalt manufacturing facility, since the production of materials in the pelletized form can take place during what is normally It could be a season of plant inactivity. Since the pellets are free flowing at room temperature, a tank or special heating associated with the storage or use of the pellets is not required. Polymer-modified bitumen pellets, free flowing, can be stored at room temperature in P882 any suitable container, resulting in lower energy consumption due to the elimination of heated tanks. The bitumen compositions produced here from the pellets or in other physical forms of the concentration can be used as a paving material for all types of paving and can also find applications in roofing membranes, shingles, waterproofing membranes, sealants , caulking, incrustation resins and protective finishes. Paving materials in general include aggregates, for example crushed stone, pebbles, sand, etc. together with the composition of bitumen. Similarly, other additives in the bitumen composition are also employed, depending on the end use to which the invention is intended. For example, the roofing material can be obtained by the addition of a suitable filler, for example asbestos, carbonates, silicas, cellulose fibers, mica, sulphates, clays, pigments and / or flame retardants, for example chlorinated waxes. For the application of crack fillers, an oxide can also be advantageously added.

EXAMPLES The following examples illustrate the P882 incorporation of the chemically reactive mixture of multipolymer components within the bitumen composition, which are capable of being granulated. The compositions, in each case, are prepared by a two-stage process, wherein at least three polymer components are reactive mixed in the bitumen and then the polymers are chemically incorporated into the bitumen with the increasing addition of a cross-linking to the mixture. The compositions prepared according to the Examples have a viscosity range of 100 poise to 10 poise at a temperature of about 200 ° C. The resulting compositions were pelletized in solid form at room temperature with conventional granulators. The resulting pellets were stored at normal room temperature over a considerable time interval, without losing their free-flowing property. The storage stability of the pellets was tested when mixed with asphalt at approximately 2% polymer charge level and during hot storage at 320 ° F for 48 hours, using ASTM test method 5892-96. According to this method, the stability is considered satisfactory if the difference in the softening temperature between the upper or lower sample, after the hot storage, is no greater than about 4 ° F.

P882 Example 1: In a 1 liter mixing vessel, 391 g of asphalt (Petro-Canada Bow River, penetration degree 150/200) was heated to 180 ° C. 139 g of polyethylene (recycled low density, melt index 1, RLDPE), 22 g of polyethylene grafted with maleic anhydride (Fusabond 101, low linear density, melt density 12, anhydride content: 0.7%) were added to the asphalt. ), 35 g of styrene-butadiene rubber (SB copolymer; Firestone Steron 210, in solid form with a molecular weight of about 70,000), and 14 g of poly (butadiene-co-acrylonitrile) copolymer functionalized with amine (Hycar; ABTN; 10% acrylonitride content, amine equivalent to 1200) in the asphalt, were reactive mixed with high shear with a Brinkman Polytron Mixer for 1.5 hours at approximately 180 ° C - 200 ° C. To this mixture, while it was still being mixed, 2 g of a total amount of sulfur in increasing amounts were added with 3 divided portions: 1 g, 0.5 g and 0.5 g at half hour intervals. After increasing loading of sulfur, the mixing and reaction continued for 1.5 hours at about 180 ° C-240 ° C to form a polymer-stabilized bitumen composition having a viscosity of about 70 poise at 200 ° C. The P882 stability of the composition was tested to determine polymer separation by diluting the bitumen to approximately 2% polymer charge level. The difference in the softening point between the top and the bottom was 1 ° F, showing an acceptable stability. The resulting composition was poured over the container to cool to room temperature to form a solidified mass. A conventional granulator was used to pellet the solid and form small free-flow pellets of a size of approximately 1/4 to 1/2 inch. The pellets were packaged in a container in the form of a plastic bottle and stored at room temperature for 30 months without losing their free-flowing property.

Example 2; The method of Example 1 was repeated with a low density recycled polyethylene having a high melt flow index (MI: 100). The viscosity of the resulting composition was 25 poise at 200 ° C, which was significantly lower than that of the composition of Example 1. The pellets made from the composition had retained their free-flowing property during the same 30 months of storage and the same conditions as the samples of Example 1.

P882 Example 3: The method of Example 1 was repeated again using the same polyethylene as used in Example 2, except that 110 g of polyethylene was used instead of 139 g to make a final granular asphalt composition containing 30% of stabilized polymers, instead of 35% polymers as in Example 1 and Example 2. The viscosity of this composition was about 18 poise at 200 ° C. The granulates obtained from this formulation also exhibited a good free-flowing property after 30 months of storage under the same conditions set forth in Example 1.

Example 4: The procedure of Example 1 was repeated one more time using polyethylene of Example 1 and also incorporating a composition prepared according to WO 94/14896, comprising a mixture of 40/20/40 de-vulcanized crumbled rubber, oil and bitumen, instead of the styrene-butadiene rubber. The viscosity of the resulting composition was about 75 poise at 200 ° C. The pellets made from the composition had retained their free flow property in a period of P882 storage for 30 months and in conditions such as those indicated for Example 1.

Example 5; The procedure of Example 1 was repeated using polyethylene of Example 1 but using a harder bitumen, namely AC-20. The stability of the composition before pelleting was tested by diluting the composition to a polymer loading level of 2%. The difference in the softening point between the upper part and the lower part was 2 ° F, showing acceptable stability. The pellets were made from the composition and had retained their free-flowing property for a storage time of 3 months and conditions as indicated for Example 1. The following Table summarizes the compositions used in the Examples: P882 Compositions of Pelet t «o

Claims (15)

1. CLAIMS I 1. A bitumen composition characterized by: 45 to 85% by weight of bitumen, 10 to 50% by weight of rigid polymer or crystalline particulate, 3 to 25% by weight of rubber compatible with bitumen and incorporating and stabilizes the particulate polymer in the bitumen, and that is stable against the separation of the particulate polymer during the dilution of the composition with the bitumen to a final use composition. The composition according to claim 1, characterized in that the polymer is present in an amount of 15 to 30% by weight, the bitumen is present in an amount of 65 to 75% by weight and the rubber is present in an amount of 5% by weight. to 15% by weight. 3. The composition according to claim 1 or 2, characterized in that the polymer is a crystalline polyolefin. 4. The composition according to claim 3, characterized in that the polyolefin is polyethylene. The composition according to claim 4, characterized in that the polyethylene is stable against separation by spherical stabilization. 6. The composition according to claim 4, P882 characterized because the polyethylene remains stable against separation by stabilization by exhaustion. The composition according to claim 1 or 2, characterized in that the polymer is a rigid styrene-based polymer. 8. The composition according to claim 7, characterized in that the styrene-based polymer is a rigid polystyrene. 9. The composition according to claim 8, characterized in that the rigid polystyrene is stable against separation by domain stabilization. The composition according to any of claims 1 to 9, characterized in that it has: been pelletized or pelletized to form pellets or granules that exhibit free flow at ambient temperatures. 11. The composition according to any of claims 1 to 9, which has been processed to form blocks, disks or sheets. 12. A method for forming a bitumen composition as claimed in any of claims 1 to 11, characterized by: (1) reactively mixing the polymeric components in the bitumen, and (2) chemically incorporating the polymer components in the bitumen. bitumen by adding every time P882 greater than a crosslinking agent. The method according to claim 12, characterized in that the crosslinking agent is sulfur. The method according to claim 12 or 13, which includes granulating or pelletizing the composition to form granules or pellets that have free flow at room temperature. The method according to claim 12 or 13, which includes processing the bitumen composition to form blocks, discs or sheets. P882