Bituminous compositions comprising lignin and process for preparing the same

Abstract

Bituminous composition comprising: (a) at least one bitumen modified with an elastomeric copolymer; (b) at least one mixture comprising lignin and a mixture of fatty acids of vegetal origin, saturated and / or unsaturated, having from 6 to 22 carbon atoms, preferably from 7 to 20 carbon atoms. The aforementioned bituminous composition can advantageously be used for the preparation of bituminous conglomerates for road use. In particular, the aforementioned bituminous composition can advantageously be used for the preparation of closed bituminous conglomerates (for example, wearing courses, binders, sub-bases) or open bituminous mixes conglomerates (for example drainage, soundproofing for wearing courses), optionally in the presence of recycled conglomerates.

Description

[0001] BITUMINOUS COMPOSITIONS COMPRISING LIGNIN AND PROCESS FOR PREPARING THE SAME

[0002] DESCRIPTION

[0003] The present invention relates to bituminous compositions comprising lignin and the process for their preparation.

[0004] More specifically, the present invention relates to a bituminous composition comprising: (a) at least one bitumen modified with an elastomeric copolymer; (b) at least one mixture comprising lignin and a mixture of fatty acids of vegetal origin.

[0005] The aforementioned bituminous composition can advantageously be used for the preparation of bituminous conglomerates for road use. In particular, the aforementioned bituminous composition can advantageously be used for the preparation of closed bituminous conglomerates (for example, wearing courses, binders, sub-bases) or open bituminous conglomerates (for example drainage, soundproofing for wearing courses), optionally in the presence of recycled conglomerates.

[0006] The present invention also relates to a process for the preparation of the aforementioned bituminous composition comprising lignin.

[0007] Furthermore, the present invention also relates to a mixture comprising lignin and a mixture of fatty acids of vegetal origin as well as the process for its preparation.

[0008] In common use, traditional bitumens or polymer-modified bitumens (PMBs) are used for the production of conglomerates, i.e. bitumens to which polymeric materials are added, in particular elastomeric copolymers, more in particular conjugated styrene-diene block copolymers, even more in particular styrenebutadiene block copolymers or styrene-isoprene block copolymers.

[0009] Bituminous compositions comprising lignin are also known.

[0010] For example, US patent application US 2018 / 0346658 relates to a composition comprising bitumen, one or more plasticity modifying agents, lignin, and optionally one or more further components; wherein said lignin is obtained by a process for treating a lignocellulosic biomass, said process comprising: (a) subjecting the lignocellulosic biomass to hydrothermal pre-treatment resulting in hydrothermally pre-treated lignocellulosic biomass; followed by

[0011] (b) subjecting at least part of said hydrothermally pre-treated lignocellulosic biomass obtained in step (a) to hydrolysis obtaining a liquid fraction comprising soluble carbohydrates, and a fibrous fraction comprising lignin, wherein said hydrolysis is acid catalysed hydrolysis and / or enzymatic hydrolysis; followed by

[0012] (c) optionally subjecting at least part of the liquid fraction obtained in step (b) to fermentation so as to ferment at least part of said soluble carbohydrates into a fermentation product, such as ethanol, methane or butanol, thus obtaining a fermentation broth.

[0013] The aforementioned composition is said to have improved properties such as mixing properties and to be usable for roads, pavements, waterproofing, asphalt roofing, adhesives, and the like.

[0014] European patent application EP 2918640 relates to a bituminous composition comprising lignin or a derivative thereof, wherein 10% by weight or more of said lignin or a derivative thereof is molecularly dissolved in said bituminous composition. The aforementioned bituminous composition is said to be usable in paving or roofing.

[0015] Yao H. et al, in “Review on Applications of Lignin in Pavement Engineering: A Recent Survey”, “Frontiers in Materials” (2022), Vol. 8 DOI: 10.3389 / fmats.2021.803524, report the use of lignin in three types of pavements such as: asphalt wherein lignin can be used as a modifier, extender, emulsifier, antioxidant and coupling agent; asphalt mixtures wherein lignin can be used as an additive; road base soils wherein lignin can be used as a soil stabiliser.

[0016] However, the use of lignin in bituminous compositions can adversely affect their chemical-physical and rheological characteristics such as, for example, penetration, softening point, storage stability, elastic recovery, cohesion, as well as their performance when used for the preparation of bituminous conglomerates.

[0017] The Applicant therefore set itself the problem of finding bituminous compositions comprising lignin that could overcome the aforementioned drawbacks.

[0018] The Applicant has now found that the addition of a mixture comprising lignin and a mixture of fatty acids of vegetal origin to a bituminous composition overcomes the aforementioned drawbacks. In particular, the Applicant has now found a bituminous composition comprising (a) at least one bitumen modified with an elastomeric copolymer; (b) at least one mixture comprising lignin and a mixture of fatty acids of vegetal origin, capable of overcoming the aforementioned drawbacks. In fact, said bituminous composition presents chemical-physical and rheological characteristics such as, for example, penetration, softening point, storage stability, elastic recovery, cohesion, comparable to the starting product, i.e. to bitumen modified with an elastomeric copolymer, and, consequently, comparable performance when used for the preparation of bituminous conglomerates. In addition, both the process of preparing the mixture comprising lignin and a mixture of fatty acids of vegetal origin, and its addition to bitumen modified with an elastomeric copolymer can be carried out easily without the need for special equipment, in a relatively short time, thus saving time and costs. The aforementioned bituminous composition can advantageously be used for the preparation of bituminous conglomerates for road use. In particular, the aforementioned bituminous composition can advantageously be used for the preparation of closed bituminous conglomerates (for example, wearing courses, binders, sub-bases) or open bituminous conglomerates (for example, drainage, soundproofing for wearing courses), optionally in the presence of recycled conglomerates.

[0019] Therefore, the subject matter of the present invention is a bituminous composition comprising:

[0020] (a) at least one bitumen modified with an elastomeric copolymer;

[0021] (b) at least one mixture comprising lignin and a mixture of fatty acids of vegetal origin, saturated and / or unsaturated, having from 6 to 22 carbon atoms, preferably from 7 to 20 carbon atoms.

[0022] For the purpose of the present description and of the following claims, the definitions of the numerical ranges always include the extreme values unless otherwise specified.

[0023] For the purpose of the present description and of the following claims, the term “comprising” also includes the terms “which essentially consists of’ or “which consists of’.

[0024] In accordance with a preferred embodiment of the present invention, said bituminous composition comprises:

[0025] (a) from 80% by weight to 99% by weight, preferably from 82% by weight to 98,5% by weight, even more preferably from 84% by weight to 98% by weight, of at least one bitumen modified with an elastomeric copolymer, with respect to the total weight of said bituminous composition;

[0026] (b) from 1% by weight to 20% by weight, preferably from 1,5% by weight to 18% by weight, even more preferably from 2% by weight to 16% by weight, of at least one mixture comprising lignin and a mixture of fatty acids of vegetal origin, saturated and / or unsaturated, having from 6 to 22 carbon atoms, preferably from 7 to 20 carbon atoms, with respect to the total weight of said bituminous composition.

[0027] In accordance with a preferred embodiment of the present invention, said bitumen modified with an elastomeric copolymer can be selected, for example, from bitumens modified with conjugated styrene-diene block copolymers, preferably styrene-butadiene block copolymers or styrene-isoprene block copolymers, more preferably from bitumens modified with block copolymers containing polystyrene and polybutadiene blocks, i.e. styrene-butadiene- styrene (SBS) block copolymers.

[0028] Specific examples of bitumens modified with styrene-butadiene- styrene block copolymers (SBS) that can be used in accordance with the present invention and are commercially available are the products known as Eliflex by Eni S.p.A.

[0029] Any type of lignin can be used for the purpose of the present invention, i.e. lignin from the paper industry or from biorefineries, or from lignocellulosic materials of various kinds.

[0030] Preferably, the lignin used for the purpose of the present invention can be obtained by hydrolysis of a lignocellulosic biomass according to any of the hydrolysis methods known in the art.

[0031] Preferably, the hydrolysis of lignocellulosic biomass can be carried out by a process comprising the following steps: (i) a pre-treatment of the starting lignocellulosic biomass to produce a pre-treated lignocellulosic biomass in order to increase the accessibility of the polymeric and oligomeric sugars it contains to subsequent enzyme action; and (ii) subjecting the pre-treated lignocellulosic biomass obtained in step (i) to enzymatic hydrolysis in order to hydrolyse the polymeric and oligomeric sugars to monomeric sugars (sugars with five and six carbon atoms, mainly glucose and xylose).

[0032] Preferably, the pre-treatment step (i) comprises hydrothermal treatment of the starting lignocellulosic biomass with water, in the vapour phase, in a pressurised reactor, and the subsequent steam explosion of the lignocellulosic biomass after hydrothermal treatment implemented by rapidly releasing the pressure applied to the lignocellulosic biomass.

[0033] Preferably, prior to the pre-treatment step (i), the starting lignocellulosic biomass can be subjected to a step (i’) of soaking in water in order to remove some of the non-lignocellulosic compounds contained in the starting lignocellulosic biomass such as, for example, inorganic salts, waxes, organic acids. During said step (i’) of soaking in water, external contaminants such as, for example, dust, stones, collection residues can also be removed.

[0034] More details relative to said pre-treatment step (i) and soaking step (i’) can be found, for example, in European Patent EP 3,241,907, incorporated herein by reference.

[0035] Optionally, said pre-treatment step (i) can be carried out in two steps as described, for example, in European Patent EP 2,414,531, incorporated herein by reference.

[0036] The aforementioned enzymatic hydrolysis step (ii) can be carried out by contacting an aqueous slurry of lignocellulosic biomass obtained in step (i), with an enzyme or a cocktail of enzymes, operating under conditions capable of promoting said enzymatic hydrolysis.

[0037] In order to obtain said aqueous slurry, water can be added to the pre-treated lignocellulosic biomass obtained in step (i), possibly water from recirculation, or an aqueous solution containing sugars can be added (for example, an aqueous solution containing sugars from enzymatic hydrolysis), in such an amount as to obtain a slurry comprising an amount of pre-treated biomass (dry weight) preferably comprised between 10% by weight and 25% by weight, relative to the total weight of said aqueous slurry.

[0038] Preferably, the aforementioned enzymatic hydrolysis step (ii) can be carried out at a pH comprised between 4.5 and 5.3 at a temperature comprised between 45°C and 65°C, and for a time comprised between 24 hours and 120 hours, under stirring.

[0039] The aforementioned enzymatic hydrolysis step (ii) can comprise one or more steps.

[0040] At the end of said hydrolysis step (ii), a mixture is obtained comprising a solid residue comprising lignin and a hydrolysate from lignocellulosic biomass comprising water and monomeric sugars with five and six carbon atoms, mainly glucose and xylose.

[0041] Thereafter, said solid residue comprising lignin is removed from said mixture according to techniques known in the art such as, for example, decanting, centrifuging, or pressing, or a combination thereof, and dried (for example, under vacuum or by heating under atmospheric pressure) obtaining a powder comprising lignin which will be used for the purpose of the present invention (hereinafter referred to as “dried lignin in powder form” for simplicity).

[0042] Preferably, the enzymatic hydrolysis of the lignocellulosic biomass can be carried out by operating as described, for example, in international patent application WO 2010 / 113130, incorporated herein by reference.

[0043] The above reported enzymatic hydrolysis processes are to be considered as illustrative and preferred embodiments for the purpose of obtaining lignin from lignocellulosic biomass and not limiting the present invention.

[0044] Various lignocellulosic biomasses can be used for the purpose of the present invention. A detailed description of lignocellulosic biomasses that can be advantageously used can be found, for example, in international patent application WO 2015 / 028156, incorporated herein by reference.

[0045] Preferably, the lignocellulosic biomass can be selected, for example, from:

[0046] - plants specifically cultivated for energy use such as, for example, miscanthus, panicum (Panicum virgatuni), common reed (Arundo donctx

[0047] - plants not specifically cultivated for energy use such as, for example, sorghum

[0048] (for example, sorghum fibre);

[0049] - scraps, residues and wastes of agricultural products such as, for example, guayule, maize (for example, maize stalks, maize cobs), soybean, cotton, flax, rapeseed, wheat (for example, wheat straw), rice (for example, rice straw, rice hull, rice husk), sugar cane (for example, sugar cane straw, sugar cane bagasse), palm (for example, palm leaves, palm trunks, palm mibrids, palm empty fruit bunches);

[0050] - scraps, residues and waste of products deriving from forestry, silviculture, or wood processing such as, for example, poplar, alder, birch;

[0051] - scarps from agri-food products intended for human consumption or animal husbandry;

[0052] - residues, not chemically treated, from the paper industry;

[0053] - waste from separate collection of municipal solid waste (for example, municipal vegetable waste, paper);

[0054] - algae such as, for example, microalgae or macroalgae, in particular macroalgae.

[0055] In accordance with a preferred embodiment of the present invention, said lignin can be dried lignin in powder form having a particle size comprised between 10 mesh and 500 mesh, preferably comprised between 15 mesh and 300 mesh.

[0056] In accordance with a preferred embodiment of the present invention, the fatty acids of vegetal origin present in said mixture can be selected, for example, from caprylic acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid.

[0057] In accordance with a preferred embodiment of the present invention, said mixture of fatty acids of vegetal origin can have a flash point comprised between 150°C and 300°C, preferably comprised between 180°C and 280°C.

[0058] In accordance with a preferred embodiment of the present invention, in said mixture said lignin and said mixture of saturated and / or unsaturated fatty acids of vegetal origin having from 6 to 22 carbon atoms, preferably from 7 to 20 carbon atoms, can be present in a ratio by weight comprised between 3: 1 and 1 :3, preferably comprised between 2.5: 1 and 1 : 1.

[0059] As mentioned above, the present invention also relates to a process for preparing the aforementioned bituminous composition comprising lignin.

[0060] Accordingly, a further object of the present invention is a process for the preparation of a bituminous composition comprising lignin comprising:

[0061] (a) mixing at least one bitumen modified with an elastomeric copolymer and at least one mixture comprising lignin and a mixture of fatty acids of vegetal origin, saturated and / or unsaturated, having from 6 to 22 carbon atoms, preferably from 7 to 20 carbon atoms, at a temperature comprised between 100°C and 200°C, preferably comprised between 110°C and 195°C, for a time comprised between 30 minutes and 10 hours, preferably comprised between 40 minutes and 9 hours, obtaining a first bituminous composition comprising lignin;

[0062] (b) optionally, mixing said first bituminous composition with at least one bitumen modified with an elastomeric copolymer at a temperature comprised between 100°C and 200°C, preferably comprised between 110°C and 195°C, for a time comprised between 30 minutes and 10 hours, preferably comprised between 20 minutes and 5 hours, obtaining a second bituminous composition comprising lignin.

[0063] It should be noted that the aforementioned process is carried out at the storage temperature of the modified bitumen, which therefore does not have to undergo any additional heating, thus saving time and costs.

[0064] The mixing of the bitumen modified with an elastomeric copolymer with the mixture comprising lignin and a fatty acid mixture, or of the bitumen composition comprising lignin with the bitumen modified with an elastomeric copolymer, can be carried out in mixers known in the art such as, for example, low shear mixers, or propeller mixers, preferably propeller mixers, operating at a mixing speed comprised between 200 rpm and 1000 rpm, preferably comprised between 250 rpm and 800 rpm.

[0065] As mentioned above, the present invention also relates to a mixture comprising lignin and a mixture of fatty acids of vegetal origin as well as the process for its preparation.

[0066] Accordingly, a further object of the present invention is a mixture comprising lignin and a mixture of fatty acids of vegetal origin, saturated and / or unsaturated, having from 6 to 22 carbon atoms, preferably from 7 to 20 carbon atoms.

[0067] Further subject matter of the present invention is a process for preparing a mixture comprising lignin and a mixture of fatty acids of vegetal origin, saturated and / or unsaturated, having 6 to 22 carbon atoms, preferably from 7 to 20 carbon atoms, comprising the following steps:

[0068] (i) mixing the dried lignin in powder form with a mixture of fatty acids of vegetal origin, saturated and / or unsaturated, having from 6 to 22 carbon atoms, preferably from 7 to 20 carbon atoms;

[0069] (ii) heating the mixture obtained in step (i) at a temperature comprised between 15°C and 180°C, preferably comprised between 20°C and 140°C, at a pressure comprised between 10 mbar and the atmospheric pressure, preferably comprised between 50 mbar and the atmospheric pressure, for a time comprised between 1 minute and 6 hours, preferably comprised between 5 minutes and 4 hours.

[0070] The mixing of the lignin with the mixture of fatty acids can be carried out in mixers known in the art such as, for example, batch mixers equipped with a mechanical propeller stirrer, a whisk stirrer, or a flat beater stirrer commonly used in dough production (for example, in the food industry), preferably batch mixers equipped with a flat beater stirrer commonly used in dough production (e.g. in the food industry), preferably batch mixers equipped with a mechanical propeller stirrer, operating at a mixing speed comprised between 100 rpm and 500 rpm, preferably comprised between 300 rpm and 400 rpm.

[0071] In order to better understand the present invention and to put it into practice, some illustrative and non-limiting examples thereof are reported below.

[0072] Analysis and characterization methods The analysis methods shown in Table 1 were used.

[0073] Table 1

[0074] * difference in Ring and Ball values between head (T) and bottom (F) after 3 days of storage at 180°C.

[0075] EXAMPLE 1 (comparative)

[0076] 315 g of SBS-modified bitumen (Eliflex HD - Eni S.p.A.) was mixed in a 500 ml can, equipped with a propeller stirrer, having the following characteristics (measured using the measurement methods shown in Table 1): - penetration 25°C (0.1 mm): 60; - softening point (Ring and Ball): 76.4°C;

[0077] -A Ring and Ball: 0.0°C; and 35 g of dried lignin in powder form resulting from the enzymatic hydrolysis of white poplar veneer (particle size 200 mesh): everything was left, under stirring (600 rpm), at 190°C, for 1 hour.

[0078] The final product (10% lignin by weight) was found to have the following characteristics (measured using the measurement methods shown in Table 1):

[0079] - penetration 25°C (0.1 mm): 45 (out-of-specification value);

[0080] - softening point (Ring and Ball): 91.0°C (out-of-specification value);

[0081] -A Ring and Ball: 1 ,0°C;

[0082] - cohesion 10°C: specimens broken before the end of the test.

[0083] EXAMPLE 2 (comparative)

[0084] 329 g of SBS-modified bitumen (Eliflex HD - Eni S.p.A.) was mixed in a 500 ml can, equipped with a propeller stirrer, having the following characteristics (measured using the measurement methods shown in Table 1):

[0085] - penetration 25°C (0.1 mm): 52;

[0086] - softening point (Ring and Ball): 78.2°C;

[0087] -A Ring and Ball: 1.0°C; and 21 g of dried lignin in powder form resulting from the enzymatic hydrolysis of white poplar veneer (particle size 120 mesh): everything was left, under stirring (600 rpm), at 190°C, for 1 hour.

[0088] The final product (6.0% lignin by weight) was found to have the following characteristics (measured using the measurement methods shown in Table 1):

[0089] - penetration 25°C (0.1 mm): 40 (out-of-specification value);

[0090] - softening point (Ring and Ball): 86.0°C (out-of-specification value);

[0091] -A Ring and Ball: 0.0°C;

[0092] - cohesion 10°C: specimens broken before the end of the test.

[0093] EXAMPLE 3 (comparative)

[0094] 329 g of SBS-modified bitumen (Eliflex HD - Eni S.p.A.) was mixed in a 500 ml can, equipped with a propeller stirrer, having the following characteristics (measured using the measurement methods shown in Table 1): - penetration 25°C (0.1 mm): 60;

[0095] - softening point (Ring and Ball): 76.4°C;

[0096] -A Ring and Ball: 0.0°C; and 7 g of dried lignin powder resulting from the enzymatic hydrolysis of white poplar veneer (particle size 200 mesh): everything was left, under stirring (600 rpm), at 190°C, for 1 hour.

[0097] The final product (2.0% lignin by weight) was found to have the following characteristics (measured using the measurement methods shown in Table 1):

[0098] - penetration 25°C (0.1 mm): 57;

[0099] - softening point (Ring and Ball): 90.5°C (out-of-specification value);

[0100] -A Ring and Ball: 0.4°C;

[0101] - cohesion 10°C: one specimen broken before the end of the test; two specimens with an average value of 7.1 J / cm2.

[0102] EXAMPLE 4 (comparative)

[0103] The lignin was treated with an aromatic oil RAE (“Residual Aromatic Extract”) (Eni Clematis RL - Eni S.p.A) operating as described below.

[0104] For this purpose, 7 g of dried lignin in powder form resulting from the enzymatic hydrolysis of white poplar veneer (particle size 200 mesh) and 11.9 g of the aromatic oil RAE (Eni Clematis RL - Eni S.p.A) were mixed manually with a paddle in a 100 ml beaker at room temperature (25°C), for 10 minutes.

[0105] 331.1 g of SBS-modified bitumen (Eliflex HD - Eni S.p.A.) was mixed in a 500 ml can, equipped with a propeller stirrer, having the following characteristics (measured using the measurement methods shown in Table 1):

[0106] - penetration 25°C (0.1 mm): 60;

[0107] - softening point (Ring and Ball): 76.4°C;

[0108] A Ring and Ball: 0.0°C; and 18.9 g of the lignin mixture in RAE aromatic oil obtained as described above: everything was left, under stirring (600 rpm), at 190°C, for 1 hour.

[0109] The final product (2.0 wt% lignin and 3.4 wt% aromatic oil RAE) was found to have the following characteristics (measured using the measurement methods shown in Table 1): - penetration 25°C (0.1 mm): 43 (out-of-specification value);

[0110] - softening point (Ring and Ball): 61.8°C (out-of-specification value);

[0111] A Ring and Ball: 1.0°C; cohesion 10°C: 5.5 J / cm2.

[0112] The lignin was treated with an aromatic oil RAE (“Residual Aromatic Extract”) (Eni Clematis RL - Eni S.p.A) as described below.

[0113] For this purpose, 18 g of dried lignin in powder form resulting from the enzymatic hydrolysis of white poplar veneer (particle size 200 mesh) and 27 g of the aromatic oil RAE (Eni Clematis RL - Eni S.p.A) were mixed manually with a paddle in a 100 ml beaker at room temperature (25°C), for 10 minutes.

[0114] 305 g of SBS-modified bitumen (Eliflex HD 50 / 70 - Eni S.p.A.) was mixed in a 500 ml can, equipped with a propeller stirrer, having the following characteristics (measured using the measurement methods shown in Table 1):

[0115] - penetration 25°C (0.1 mm): 60;

[0116] - softening point (Ring and Ball): 76.4°C;

[0117] -A Ring and Ball: 0.0°C; and 45 g of the lignin mixture in RAE aromatic oil obtained as described above: everything was left, under stirring (600 rpm), at 190°C,for 1 hour.

[0118] The final product (5.1 wt.% lignin and 7.7 wt.% aromatic oil RAE) was found to have the following characteristics (measured using the measurement methods shown in Table 1):

[0119] - penetration 25°C (0.1 mm): 77 (out-of-specification value);

[0120] - softening point (Ring and Ball): 86.5°C (out-of-specification value);

[0121] A Ring and Ball: 0.8°C;

[0122] - cohesion 10°C: 3.2 J / cm2;

[0123] - elastic recovery at 25°C: 80%.

[0124] EXAMPLE 6 (invention)

[0125] For this purpose, a mixture of lignin and a mixture of fatty acids was prepared operating as follows.

[0126] In a 100 ml beaker, 21 g of dried lignin in powder form resulting from the enzymatic hydrolysis of white poplar veneer (particle size 120 mesh) and 10.5 g of the Prime Fatty Acid by-Product mixture (CAS 70321-72-1) (Temix Oleo) (lignimfatty acid mixture 2: 1 ratio by weight) were mixed manually with a paddle at room temperature (25°C), at atmospheric pressure, for 10 minutes. 318.5 g of SBS-modified bitumen (Eliflex HD - Eni S.p.A.) was mixed in a

[0127] 500 ml can, equipped with a propeller stirrer, having the following characteristics (measured using the measurement methods shown in Table 1):

[0128] - penetration 25°C (0.1 mm): 52;

[0129] - softening point (Ring and Ball): 74.6°C; -A Ring and Ball: 1.0°C; and 31.5 g of the lignimfatty acid mixture obtained as described above: everything was left, under stirring (600 rpm), at 190°C, for 1 hour.

[0130] The final product (6.0 wt.% lignin and 3.0 wt.% fatty acid mixture - 9.0 wt.% lignimfatty acid mixture) was found to have the characteristics shown in Table 2 (measured using the measurement methods shown in Table 1).

[0131] Table 2 also shows the specifications of the SBS-modified bitumen (Eliflex HD - Eni S.p.A.) for comparison (specifications are measured using the measurement methods shown in Table 1).

[0132] Table 2

[0133] * difference in Ring and Ball values between head (T) and bottom (F) after 3 days of storage at 180°C.

[0134] From the data shown in Table 2, it can be seen that the bitumen composition in accordance with the present invention exhibits characteristics in accordance with the specifications of the modified bitumen Eliflex HD (Eni S.p.A.) as such. EXAMPLE 7 (invention)

[0135] For this purpose, a mixture of lignin and a mixture of fatty acids was prepared as follows.

[0136] In a 500 ml beaker, 160 g of dried lignin in powder form resulting from the enzymatic hydrolysis of white poplar veneer (particle size 120 mesh) and 80 g of the Prime Fatty Acid by-Product mixture (CAS 70321-72-1) (Temix Oleo) (lignimfatty acid mixture 2: 1 ratio by weight) were mixed manually with a paddle at room temperature (25°C), at atmospheric pressure, for 10 minutes.

[0137] 3760 g of SBS-modified bitumen (Eliflex HD - Eni S.p.A.) was mixed in a 5 1 tin, equipped with a propeller stirrer, having the following characteristics (measured using the measurement methods shown in Table 1):

[0138] - penetration 25°C (0.1 mm): 52;

[0139] - softening point (Ring and Ball): 74.6°C;

[0140] -A Ring and Ball: 1.0°C; and 240 g of the lignimfatty acid mixture obtained as described above: everything was left, under stirring (600 rpm), at 190°C for 1 hour.

[0141] The final product (4.0 wt.% lignin and 2.0 wt.% fatty acid mixture - 6.0 wt.% lignimfatty acid mixture) was found to have the characteristics shown in Table 3 (measured using the measurement methods shown in Table 1).

[0142] Table 3 also shows the specifications of the SBS-modified bitumen (Eliflex HD - Eni S.p.A.) for comparison (specifications are measured using the measurement methods shown in Table 1).

[0143] Table 3 difference in Ring and Ball values between head (T) and bottom (F) after 3 days of storage at 180°C. From the data shown in Table 3, it can be seen that the bitumen composition in accordance with the present invention exhibits characteristics in accordance with the specifications of the modified bitumen Eliflex HD (Eni S.p.A.) as such. EXAMPLE 8 (invention)

[0144] For this purpose, a mixture of lignin and a mixture of fatty acids was prepared as follows.

[0145] In a 100 ml beaker, 28 g of dried lignin in powder form resulting from the enzymatic hydrolysis of white poplar veneer (particle size 120 mesh) and 14 g of the Prime Fatty Acid by-Product mixture (CAS 70321-72-1) (Temix Oleo) (lignimfatty acid mixture 2: 1 ratio by weight) were mixed manually with a paddle at room temperature (25°C), at atmospheric pressure, for 10 minutes.

[0146] 308 g of SBS-modified bitumen (Eliflex HD - Eni S.p.A.) was mixed in a 500 ml can, equipped with a propeller stirrer, having the following characteristics (measured using the measurement methods shown in Table 1):

[0147] - penetration 25°C (0.1 mm): 52;

[0148] - softening point (Ring and Ball): 74.6°C;

[0149] -A Ring and Ball: 1.0°C; and 42 g of the lignimfatty acid mixture obtained as described above: everything was left, under stirring (600 rpm), at 190°C, for 1 hour.

[0150] The final product (8.0 wt.% lignin and 4.0 wt.% fatty acid mixture - 12.0 wt.% lignimfatty acid mixture) was found to have the characteristics shown in Table 4 (measured using the measurement methods shown in Table 1).

[0151] Table 4 also shows the specifications of the SBS-modified bitumen (Eliflex HD - Eni S.p.A.) for comparison (specifications are measured using the measurement methods shown in Table 1).

[0152] Table 4

[0153] * difference in Ring and Ball values between head (T) and bottom (F) after 3 days of storage at 180°C.

[0154] From the data shown in Table 4, it can be seen that the bitumen composition in accordance with the present invention exhibits characteristics in accordance with the specifications of the modified bitumen Eliflex HD (Eni S.p. A.) as such. EXAMPLE 9 (invention)

[0155] To the bituminous composition (6.0 wt% lignin and 3.0 wt% fatty acid mixture - 9.0 wt% lignimfatty acid mixture) obtained as described in Example 6, SBS-modified bitumen (Eliflex HD 50 / 70 - Eni S.p. A.) was added as described below.

[0156] 1000 g of the bituminous composition (6.0% by weight of lignin and 3.0% by weight of fatty acid mixture - 9.0% by weight of lignin Tatty acid mixture) obtained as described in Example 6 and 3000 g of SBS-modified bitumen (Eliflex HD 50 / 70 - Eni S.p. A.) having the same characteristics as the one used in Example 6 were mixed in a 5 1 tin, equipped with a propeller stirrer: everything was left under stirring (600 rpm), at 190°C, for 1 hour.

[0157] The final product (1.5 wt.% lignin and 0.75 wt.% fatty acid mixture - 2.25 wt.% lignimfatty acid mixture) was found to have the characteristics shown in Table 5 (measured using the measurement methods shown in Table 1).

[0158] Table 5 also shows the specifications of the SBS-modified bitumen (Eliflex HD - Eni S.p.A.) for comparison (specifications are measured using the measurement methods shown in Table 1). Table 5

[0159] * difference in Ring and Ball values between head (T) and bottom (F) after 3 days of storage at 180°C.

[0160] From the data shown in Table 5, it can be seen that the bitumen composition in accordance with the present invention exhibits characteristics in accordance with the specifications of the modified bitumen Eliflex HD (Eni S.p.A.) as such.

Claims

CLAIMS1. Bituminous composition comprising:(a) at least one bitumen modified with an elastomeric copolymer;(b) at least one mixture comprising lignin and a mixture of fatty acids of vegetal origin, saturated and / or unsaturated, having from 6 to 22 carbon atoms, preferably from 7 to 20 carbon atoms.

2. Bituminous composition according to claim 1, wherein said bituminous composition comprises:(a) from 80% by weight to 99% by weight, preferably from 82% by weight to 98,5% by weight, even more preferably from 84% by weight to 98% by weight, of at least one bitumen modified with an elastomeric copolymer, with respect to the total weight of said bituminous composition;(b) from 1% by weight to 20% by weight, preferably from 1,5% by weight to 18% by weight, even more preferably from 2% by weight to 16% by weight, of at least one mixture comprising lignin and a mixture of fatty acids of vegetal origin, saturated and / or unsaturated, having from 6 to 22 carbon atoms, preferably from 7 to 20 carbon atoms, with respect to the total weight of said bituminous composition.

3. Bituminous composition according to claim 1 or 2, wherein said bitumen modified with an elastomeric copolymer is selected from bitumens modified with conjugated styrene-diene block copolymers, preferably styrene-butadiene block copolymers or styrene-isoprene block copolymers, more preferably from bitumens modified with radial type block copolymers containing polystyrene and polybutadiene blocks, i.e. styrene-butadiene-styrene (SBS) block copolymers.

4. Bituminous composition according to any one of the previous claims, wherein said lignin is dried lignin in powder form having a particle sizes comprised between 10 mesh and 500 mesh, preferably comprised between 20 mesh and 300 mesh.

5. Bituminous composition according to any one of the previous claims, wherein the fatty acids of vegetal origin present in said mixture are selected from caprylic acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid.

6. Bituminous composition according to any of the previous claims, whereinsaid mixture of fatty acids of vegetal origin has a flash point comprised between 150°C and 300°C, preferably comprised between 180°C and 280°C.

7. Bituminous composition according to any of the previous claims, wherein in said mixture said lignin and said mixture of fatty acids of vegetal origin, saturated and / or unsaturated, having from 6 to 22 carbon atoms, preferably from 7 to 20 carbon atoms, are present in a weight ratio comprised between 3: 1 and 1 :3, preferably comprised between 2.5: 1 and 1 :1.

8. Process for the preparation of a bituminous composition comprising lignin comprising:(a) mixing at least one bitumen modified with an elastomeric copolymer and at least one mixture comprising lignin and a mixture of fatty acids of vegetal origin, saturated and / or unsaturated, having from 6 to 22 carbon atoms, preferably from 7 to 20 carbon atoms, at a temperature comprised between 100°C and 200°C, preferably comprised between 110°C and 195°C, for a time comprised between 30 minutes and 10 hours, preferably comprised between 40 minutes and 9 hours, obtaining a first bituminous composition comprising lignin;(b) optionally, mixing said first bituminous composition with at least one bitumen modified with an elastomeric copolymer at a temperature comprised between 100°C and 200°C, preferably comprised between 110°C and 195°C, for a time comprised between 30 minutes and 10 hours, preferably comprised between 40 minutes and 9 hours, obtaining a second bituminous composition comprising lignin.

9. Mixture comprising lignin and a mixture of fatty acids of vegetal origin, saturated and / or unsaturated, having from 6 to 22 carbon atoms, preferably from 7 to 20 carbon atoms.

10. Process for the preparation of a mixture comprising lignin and a mixture of fatty acids of vegetal origin, saturated and / or unsaturated, having from 6 to 22 carbon atoms, preferably from 7 to 20 carbon atoms, comprising the following steps:(i) mixing the dried lignin in powder form with a mixture of fatty acids of vegetalorigin, saturated and / or unsaturated, having from 6 to 22 carbon atoms, preferably from 7 to 20 carbon atoms;(ii) heating the mixture obtained in step (i) at a temperature comprised between 15°C and 180°C, preferably comprised between 20°C and 140°C, at a pressure comprised between 10 mbar and the atmospheric pressure, preferably comprised between 50 mbar and the atmospheric pressure, for a time comprised between 1 minute and 6 hours, preferably comprised between 5 minutes and 4 hours.

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