EP2989162A1

EP2989162A1 - Premix composition for bitumens

Info

Publication number: EP2989162A1
Application number: EP14722292.1A
Authority: EP
Inventors: Vincent PALLUAULT; Sébastien QUINEBECHE
Original assignee: Arkema France SA
Current assignee: Arkema France SA
Priority date: 2013-04-25
Filing date: 2014-04-18
Publication date: 2016-03-02
Also published as: FR3005058A1; MX2015014794A; BR112015026984A2; FR3005058B1; WO2014174190A1; US20160102207A1

Abstract

The present invention relates to a premix composition for bitumens, comprising: - from 35% to 65%, by weight of the composition, of bitumen, - from 5% to 65%, by weight of the composition, of a first copolymer of an alpha‑olefin and of an unsaturated carboxylic acid ester, characterized in that it additionally comprises from 5% to 65% by weight of a second copolymer of an alpha-olefin, an unsaturated epoxide and an unsaturated carboxylic acid ester and in that the aforesaid first copolymer (A) and the aforesaid second copolymer (B) represent between 35% and 65% by weight of said composition. The invention also relates to a bituminous mix comprising this composition and also the use of this composition for the preparation of such a mix.

Description

PRE-MIXING COMPOSITION FOR BITUMES

Field of the invention

The invention belongs to the field of bituminous mixes and more specifically to the technologies relating to functional additives added to the mixture of bitumen and aggregates in order to confer on it particular physico-chemical and mechanical properties. More specifically, the invention relates to a premix composition directly usable to be dispersed in the mixture of bitumen and aggregates to give it the desired properties.

The invention also relates to a bituminous mix comprising a specific proportion (concentration range in the bitumen mixture and aggregates, relative weight) of the aforesaid premix and the use of this premix for obtaining an asphalt mix.

State of the art

The use of bitumen in the manufacture of materials for road and industrial applications is known for a long time: bitumen is the main hydrocarbon binder used in the field of road construction or civil engineering.

Bitumen or asphalt is the heaviest portion in the process of oil distillation. Due to the different origins and processes of distillation of such oils, the resulting bitumen can have a wide range of properties and characteristics. In the present invention, bitumen refers not only to the direct distillation petroleum product or to the distillation of petroleum at reduced pressures, but also to products derived from the extraction of tar and tar sands, oxidation products and and / or fluxing with carbon solvents comprising paraffins and waxes of such bituminous materials, as well as blown or semi-blown bitumens, synthetic bitumens (such as those described for example in FR-A-2853647), tars, petroleum resins or indene-coumarone resins mixed with aromatic and / or paraffinic hydrocarbons and mixtures thereof, mixtures of such bituminous materials with acids, and the like.

The main application for bitumen is in bituminous mixes, in which the bitumen is mixed with aggregates which may be different sizes, shapes and chemical natures. These bituminous mixes are used in particular for the construction, repair and maintenance of sidewalks, roads, highways, parking lots or airport runways and service roads and any other running surface. In the present invention, the aggregates include, but are not limited to, mineral aggregates which are the product of quarries as well as aggregates recovered from previous mixes ("Reclaimed Asphalt Pavement", RAP), as described for example in the standard AFNOR XP P98-135, December 2001, Asphalt Handbook, MS-4 7 ^th edition, published by the Asphalt Institute, USA), produced from the demolition of buildings and their mixtures as well as organic fibers and inorganic materials, such as glass, metal or carbon fibers, as well as cellulose, cotton, polypropylene, polyester, polyvinyl alcohol and polyamide fibers.

The use of bitumen in the manufacture of materials for road and industrial applications is known for a long time: bitumen is the main hydrocarbon binder (to bind the aggregates between them) used in the field of road construction or civil engineering. To be used as a binder in these different applications, the bitumen must have certain physicochemical properties. One of the most important properties is the hardness of the bitumen; this must be at sufficiently high temperatures to avoid rutting caused by traffic. Another very important characteristic is the viscosity of the bitumen; the bitumen must be sufficiently fluid at the lowest possible application temperatures.

One way to harden a bitumen is to blow it. Blown bitumens are manufactured in a blowing unit, passing a flow of air and / or oxygen through a starting bitumen. This thermal oxidation operation may be conducted in the presence of an oxidation catalyst, for example phosphoric acid. Generally, the blowing is carried out at high temperatures, of the order of 200 to 300 ° C, for relatively long periods of time typically between 30 minutes and 2 hours, continuously or batch. This blowing process has a number of disadvantages which make this technique very often unacceptable.

Another way to harden a bitumen, or to modify its mechanical properties, is to add polymers to it. These polymers make it possible in particular to improve the cohesion of the binder, to improve the elastic properties of the binder, to increase the plasticity range of the bitumen, to increase the resistance to deformation and also to increase the bitumen hardness by decreasing its penetrability and thermal susceptibility, as well as improving its rheological properties. At operating temperatures, these characteristics are therefore significantly improved, which will reduce or even eliminate the risk of cracking and rutting, which results in very low maintenance and maintenance costs. In addition, thanks to this polymer modification, it is possible to implement much finer road ribbons with unmodified bitumen, while having superior mechanical performance.

At present, the current technology for introducing these polymeric additives follows the following steps. Firstly, in a first step, the polymeric additives are added to all the necessary bitumen, or almost, to make the bituminous mix (final), which constitutes a mixture identified as "modified bitumen" or "Binder", then in a second step, the aggregates, with possibly additional bitumen, are added to this modified bitumen to form the bituminous mix.

This technique is not satisfactory. It imperatively requires two steps to achieve the bituminous mix which takes not only a relatively long preparation time but also requires expensive installations. In addition, this technique has the major disadvantage of not allowing the preparation in situ, closer to the needs of operators, bituminous mix to be applied, so that the latter having already been prepared before, It is likely to have degraded performance (hardening by thermo-oxidative aging, separation and segregation of the polymer and bitumen phases, increase in viscosity).

Recently, a completely different technique in its process of preparation of bituminous mix has appeared. It aims at overcoming the disadvantages of the aforementioned preparation technique by allowing a one-step preparation of the bituminous mix, which is moreover in situ, that is to say on the site of coating of the aggregates by the binder. bituminous. This technique for preparing the bituminous mix consists in producing a premix combining bitumen with a quantity of one or more polymers. This pre-mix is supplied to the operators who, according to the particularities of their needs in the field, realize the bituminous mix by adding this premix to bitumen and aggregates. At present, there is known the use of polymers ECB ( "Ethylene Copolymer Bitumen" combination of a bitumen with a copolymeric Evatane ^® or Lotryl ^®), polyethylene (PE) and polypropylene (PP) for these compositions premixing but they do not give full satisfaction both from the point of view of the mechanical properties of the bituminous binder, in particular the elastic return and the thermal susceptibility (plasticity interval).

It is also known to use a terpolymer of the ethylene- (meth) acrylate-glycidyl methacrylate type which makes it possible to improve the elastic return and thermal susceptibility properties, but it is also known that this type of polymer, reacting with bitumen, is very difficult to use at more than five percent (5%) in the bitumen without seeing the appearance of the bitumen deteriorate by the appearance of gels (US 5306750).

Documents US 6020404, WO 2006/107907 and US 2004/0198874 are known, but none of these disclosures propose the solution of making a premix of bitumen and of particular polymers (in the absence of aggregates, representing at least 90% of the weight of the final bituminous mix) which is subsequently dispersed in a bitumen and aggregate assembly (final bituminous mix).

Brief description of the invention

Surprisingly, the applicant has discovered, in contradiction with the teachings of the prior art that it is possible to prepare a premix containing an epoxide functionalized polymer by associating it with a copolymer of an alpha olefin and of an unsaturated carboxylic acid ester and using a thermoplastic mixing tool. Indeed, it was (re) known that a mixture Lotryl ^® / Lotader ^® too concentrated in the bitumen resulted in too high viscosity and problems of heterogeneity (formation of gels).

In addition, since the levels of polymers present in this premix are greater than 35%, the use of this premix is economically viable for the preparation of bituminous mixes in a single step.

The present invention thus relates to a premix composition for bituminous mix, comprising: from 35% to 65%, by weight of the composition, of bitumen,

from 5% to 65% by weight of the composition of a first copolymer (A) of an alpha olefin and an unsaturated carboxylic acid ester, characterized in that it further comprises % to 65% by weight of a second copolymer (B) of an alpha olefin, an unsaturated epoxide and an unsaturated carboxylic acid ester and in that the aforesaid first copolymer (A) and the aforesaid second copolymer (B) represent between 35% and 65% by weight of said composition.

According to a possibility that can be envisaged with the present invention, the premix composition will consist solely of the three elements referred to above, namely the bitumen and the first and second copolymers.

Other features or embodiments of the invention are presented below:

advantageously, the mass ratio of (B) / [(A) + (B)] is between 0.15 and

0.5, preferably between 0.25 and 0.35;

the composition according to the invention consists of the bitumen and the first and second aforementioned copolymers;

according to one advantageous aspect of the invention, the alpha olefin of the abovementioned first and second copolymers (A) and (B) consists of an ethylene, propylene, 1-butene, isobutene, 1-pentene and 1-hexene group, 1 decene, 4-methyl-1-butene, 4,4-dimethyl-1-pentene, vinylcyclohexane, styrene, methylstyrene, styrene substituted with alkyls, and preferably with ethylene;

according to another advantageous aspect of the invention, the unsaturated carboxylic acid ester of the above-mentioned first and second copolymers (A) and (B) consists of a

alkyl (meth) acrylate, the alkyl group having up to 24 carbon atoms;

according to yet another advantageous aspect of the invention, the unsaturated epoxide of the copolymer (B) consists of an aliphatic glycidyl ester / ether or an alicyclic glycidyl ester / ether;

according to a preferred embodiment of the invention, the second copolymer (B) is an ethylene / alkyl (meth) acrylate / glycidyl (meth) acrylate copolymer, having from 0.1% to 65% by weight of alkyl (meth) acrylate of which alkyl has from 1 to 10 carbons and up to 12% by weight of glycidyl (meth) acrylate;

according to a preferred embodiment of the invention, the first copolymer (A) is an ethylene / alkyl (meth) acrylate copolymer whose alkyl contains from 1 to 10 carbons and up to 65% by weight of meth) acrylate.

The invention notably has the advantages of being able to be implemented in situ, without any deterioration of the bituminous mix and for an economic gain (application time, labor, quantity of bituminous mix corresponding to the real need) .

The present invention also relates to a bituminous mix comprising aggregates and bitumen characterized in that it comprises a premix composition as defined above. Preferably, said premix composition is present between 1% and 15% by weight, preferably between 3% and 8%, in the bituminous mix.

Finally, the invention relates to the use of the abovementioned composition for the preparation of a bituminous mix.

The following description is given solely for illustrative and not limiting.

Detailed description of the invention

In the case of bitumen, this element may consist of any element falling within the definition or under the name of bitumen such that the person skilled in the art can apprehend it without undue effort.

As regards the second copolymer (B), it is a copolymer of an alpha olefin comprising at least one unsaturated epoxide and at least one unsaturated carboxylic acid ester.

The unsaturated epoxide can be chosen from: aliphatic glycidyl esters and ethers such as rallyl glycidyl ether, vinyl glycidyl ether, glycidyl maleate and itaconate, glycidyl acrylate and methacrylate, and

alicyclic glycidyl esters and ethers such as 2-cyclohexene-1-glycidyl ether, cyclohexene-4,5-diglycidylcarboxylate, cyclohexene-4-glycidyl carboxylate, 5-norbornene-2-methyl-2-glycidyl carboxylate and endocis-bicyclo (2,2,1) -5-heptene-2,3-diglycidyl dicarboxylate.

Advantageously, glycidyl (meth) acrylate is used.

The unsaturated carboxylic acid ester may be, for example, an alkyl (meth) acrylate, the alkyl group possibly having up to 24 carbon atoms.

Examples of alkyl acrylate (or methacrylate) which may be used are, in particular, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, acrylate and the like. ethylhexyl.

The alpha olefin may be ethylene, propylene, 1-butene, isobutene, 1-pentene, 1-hexene, 1-decene, 4-methyl-1-butene, 4,4 dimethyl-1-pentene, vinylcyclohexane, styrene, methylstyrene, styrene substituted with alkyls. Advantageously, ethylene is used.

The unsaturated epoxide can be grafted or copolymerized with the alpha olefin and the unsaturated carboxylic acid ester. The copolymerization is preferred.

Advantageously, (B) is an ethylene / alkyl (meth) acrylate copolymer whose alkyl has from 1 to 10 carbons / glycidyl (meth) acrylate and containing up to 65% by weight of (meth) acrylate and up to 12% by weight of epoxide.

As regards the first copolymer (A), it is a copolymer of an alpha olefin comprising at least one unsaturated carboxylic acid ester. The alpha olefin and the unsaturated carboxylic acid ester may be chosen from the same products already mentioned above for the copolymer (B).

Advantageously, (A) is an ethylene / alkyl (meth) acrylate copolymer whose alkyl has from 1 to 10 carbon atoms and containing up to 65% by weight of (meth) acrylate.

The premix according to the invention is produced according to a one-step process in which the ingredients are mixed to give a homogeneous composition and perform any chemical reactions between components. This premix can be prepared by mixing the various constituents by the conventional means of implementation of thermoplastics such as extrusion or kneading. It is possible to use an internal mixer, a co-kneader or a co-rotating twin-screw extruder. Preferably, the compositions are produced at a temperature of between 100 and 300 ° C.

Obtaining the formulations of the compositions tested:

Although the premix according to the invention is used during the step of coating the aggregates, its characterization is carried out by dilution in an unmodified bitumen in order to form a binder of composition equivalent to that obtained during the step of coating the aggregates. In fact, the elastic return and viscosity properties are conventionally measured on the binder and not on the bituminous mix.

The premixes were prepared using a Plastograph Brabender ^® internal mixer at a temperature of 160 ° C and a rotational speed of the rotors of 60 rpm ("round per minute" or rpm). The polymers are first introduced to be melted and intimately mixed. The bitumen is then introduced into the internal mixer after being preheated to 150 ° C. Adding the bitumen should be slow enough (a few minutes) to allow good incorporation into the polymer blend. The mixing time after introduction of all components is ten (10) minutes.

The binders were prepared in a reactor maintained at 160 ° C. and equipped with a mechanical stirring system by mixing 25 g of premix and 475 g of non-additive bitumen. The amount of premix used represents 5% of the binder thus obtained. The stirring speed is 400 rpm and the mixing time is 2 hours. The binder then undergoes a heat treatment of 24 hours (a full day) at 190 ° C. before evaluation of these elastic return and viscosity properties.

Tests performed:

Viscosity test

The viscosity measurements are carried out using a viscometer of the "Brookfield viscometer" type. The measuring device used is a Brookfield ^® DVIII viscometer. The principle of measurement is based on measuring the torque (proportional to the shear stress) necessary to keep constant the rotational angular velocity (proportional to the shear rate) of a mobile immersed in the modified bitumen, and deduce proportionally the viscosity of the latter.

The measurement is performed using a SC4-21 mobile (ISO 2555 standard). Between 5 to

10 mL (milliliter) of modified bitumen are introduced into the measuring chamber maintained at 135 ° C. The values given in the examples below correspond to a rotational speed of the mobile of 20 rpm and are expressed in mPa.s (milli Pascal seconds). The accuracy of the measurement is ± 10% of the indicated value.

Elastic return test

The elastic return of a modified bitumen is an indicator that makes it possible to characterize the capacity of the binder to recover its original geometric characteristics following a deformation. It is determined by means of a laboratory test using apparatus similar to that of the ductility test and that of force-ductility, a device commonly referred to as a "ductilimeter". The measuring device used is a Fröwag ^® type 1.723 ductilimeter.

The measurement is carried out as described below according to Standard NF EN 13398. After thermal equilibrium of the test pieces placed in the apparatus (30 minutes in a water bath thermostatically controlled at 25 ° C.), these are drawn at 50 mm. / min (millimeter per minute) to undergo an elongation of 200 mm. Within 10 seconds after the end of the stretching, the specimens are then cut in their medium and the shrinkage length of the specimen is measured after 30 minutes. The value of the springback is the percentage of shrinkage length of the specimen reduced to its total length. An elastic return rate of 100% corresponds to a binder that completely covers its original dimensions (before stretching).

Raw materials of the compositions tested:

The bitumen used is a bitumen having a penetrability, determined according to the methods of the NF EN1426 standard, in the range of 50/70.

Lotader ^® AX8900: terpolymer of ethylene, methyl acrylate (24% by weight) and glycidyl methacrylate (8% by weight) produced by ARKEMA having an MFI (190 ° C, 2.16 kg measured according to ISO 1133) of 6 g / 10 min. Lotryl 17BA07 ^®: copolymer of ethylene and butyl acrylate (17 wt%) produced by Arkema having an MFI (190 ° C, 2.16 kg measured according to ISO 1133) of 7 g / 10 min.

Test results:

The bituminous binder must have certain advantageous characteristics.

Here are reported in a non-exhaustive way the results relating to a bituminous binder obtained from the premix according to the present invention. In this context, three characteristics were particularly targeted, namely:

the viscosity at 135 ° C of the bituminous binder which should ideally be less than 3000 mPa.s; and

the elastic return (%) which must be greater than 60% and preferably greater than 70%); and finally

the absence of gel (observation with the naked eye) at the level of the bituminous binder.

The table below reports some of the test results obtained by the licensee. Subject to interpretation, these results allowed the licensee to define the invention as set forth in the set of appended claims.

Pre-Rate (A) (B) / Viscosity Appearance Back Mixture Lotryl® Lotader® + [(A) + Surface at 135 ° C Elastic

17BA07 AX8900 (B) (B)] (mPA.s) (%)

(A) (B)

1 50% 0% 50% 0 Smooth 1520 41

2 45% 5% 50% 0.1 Smooth 1850 46

3 40% 10% 50% 0.2 Smooth 2230 63

4 35% 15% 50% 0.3 Smooth 2630 75

5 30% 20% 50% 0.4 Smooth 3090 80

6 20% 30% 50% 0.6 Gelled 3680 82

7 10.5% 4.5% 15% 0.3 Smooth 910 44

8 17.5% 7.5% 25% 0.3 Smooth 1130 55

9 21% 9% 30% 0.3 Smooth 1550 58

10 26.5% 11.5% 38% 0.3 Smooth 1790 68

11 28% 12% 40% 0.3 Smooth 1880 72

12 42% 18% 60% 0.3 Smoothing 2820 80

13 49% 21% 70% 0.3 Gelled 3460 69

Claims

A premix composition for bituminous mix comprising:

from 35% to 65%, by weight of the composition, of bitumen,

from 5% to 65%, by weight of the composition, of a first copolymer (A) of an alpha olefin and an unsaturated carboxylic acid ester,

characterized in that it further comprises from 5% to 65% by weight of a second copolymer (B) of an alpha olefin, an unsaturated epoxide and an unsaturated carboxylic acid ester and in that the aforesaid first copolymer (A) and the aforesaid second copolymer (B) represent between 35% and 65% by weight of said composition.

2. Composition according to claim 1, characterized in that the mass ratio of (B) / [(A) + (B)] is between 0.15 and 0.5, preferably between 0.25 and 0.35. .

3. Composition according to any one of the preceding claims, characterized in that said composition consists of the bitumen and the first and second aforesaid copolymers.

4. Composition according to any one of the preceding claims, characterized in that the alpha olefin of the above-mentioned first and second copolymers (A) and (B) consists of an ethylene, propylene, 1-butene, isobutene and 1-pentene group. 1-hexene, 1-decene, 4-methyl-1-butene, 4,4-dimethyl-1-pentene, vinylcyclohexane, styrene, methylstyrene, styrene substituted with alkyls, and preferably ethylene.

5. Composition according to any one of the preceding claims, characterized in that the unsaturated carboxylic acid ester of the aforesaid first and second copolymers (A) and (B) consists of an alkyl (meth) acrylate, the grouping alkyl having up to 24 carbon atoms.

6. Composition according to any one of the preceding claims, characterized in that the unsaturated epoxide of the copolymer (B) consists of an aliphatic glycidyl ester / ether or an alicyclic glycidyl ester / ether.

7. Composition according to any one of the preceding claims, characterized in that the second copolymer (B) is an ethylene / alkyl (meth) acrylate / glycidyl (meth) acrylate copolymer, having from 0.1% to 65% by weight. % by weight of alkyl (meth) acrylate of which alkyl has 1 to 10 carbons and up to 12% by weight of glycidyl (meth) acrylate.

8. Composition according to any one of the preceding claims, characterized in that the first copolymer (A) is an ethylene / alkyl (meth) acrylate copolymer whose alkyl has from 1 to 10 carbons and up to 65% o by weight of (meth) acrylate.

9. bituminous mix according to any one of the preceding claims, comprising aggregates and bitumen characterized in that it comprises a premix composition according to any one of the preceding claims.

10. Bituminous mix according to claim 9, characterized in that said premix composition is present between 1% and 15% by weight, preferably between 3% o and 8% o, in the bituminous mix.

11. Use of the premix composition according to one of claims 1 to 8 for the preparation of a bituminous mix.