NL1009695C2 - Composition containing bitumen and mineral particles with a polymer coating, and a process for the preparation of mineral particles with a polymer coating. - Google Patents

Description

- 1 - PN 9359

COMPOSITION CONTAINING BITUMES AND MINERAL PARTICLES WITH A PQLYMER LAYER. AND A PROCESS FOR THE 5 PREPARATION OF MINERAL PARTICLES WITH A PQLYMER COATING

The invention relates to a composition containing bitumen and mineral particles, which particles are provided with a coating of a polymer.

Such compositions can be used, for example, in asphalt and roof coverings. Asphalt is usually made up of 15 mineral particles of different diameters that are enveloped and bonded together by a bituminous binder. Most of the particles form a mineral skeleton. Bitumen holds the skeleton together, filling at least a portion of the voids 20 between the particles. The bitumen can be modified or unmodified. The mineral skeleton largely provides the load-bearing capacity of the asphalt.

Bitumen are highly viscous liquids or solids, consisting essentially of hydrocarbons or derivatives thereof, which are almost entirely soluble in carbon sulfur. Both natural and factory bitumen can be used in the composition according to the invention.

Mineral particles can be subdivided by particle diameter. Particles with a diameter predominantly larger than 2 mm are called stone or 1009695-2 gravel. Particles with a diameter mainly between 63μπι and 2 mm are called sand. Particles with a diameter predominantly smaller than 63μιη are called filler. Examples of mineral particles of various diameters are crushed stone, gravel, sand and combinations thereof.

A mixture of bitumen and filler is called a mortar.

Mortar is used to fill the mineral skeleton. Mortar can partially or completely fill the hollow space between the skeleton, or be present in such a large amount that skeleton parts are pressed apart. In the latter case we speak of overfilled asphalt. In overfilled asphalt, the filling must also have load-bearing capacity. The properties of a mortar are determined, inter alia, by the ratio between the amount of bitumen and the amount of filler and the type of bitumen and the type of filler, and by the presence of any additives.

From US patent US 5,219,901 (W.J. Burke) 15.06.1993, column 2, lines 38-45, a composition is known containing bitumen and mineral particles, which particles are coated with a polymer.

The described composition contains particles of various particle diameters, which particles are coated with a high molecular weight organic polymer, which polymer is soluble in organic solvents but insoluble in water. The coating is applied by contacting the particles with a water-diluted polymer emulsion, decanting the excess emulsion, and then drying the particles. The particles are then mixed with molten bitumen.

A drawback of the known composition is that its use results in asphalt on which rutting can still occur relatively quickly. The object of the invention is to provide a composition which does not have, or to a much lesser extent, said drawback. This object is achieved in that the composition according to the invention is characterized in that the composition contains mineral particles with a particle diameter <(less than) 63 µm, which particles are provided with a polymer coating, which coating is applied to the particles from an aqueous solution. of a polymer, which polymer contains monomer units in the solution containing carboxylate anions.

Although a composition containing bitumen and a water-soluble copolymer is known from Japanese patent specification 20 JP-A-62079268, the addition of the copolymer is done there by mixing the copolymer with the bitumen. There is no question of a solution of the polymer, or the application of a coating of the polymer on mineral particles with a particle diameter <63 µm. The composition known from JP-A-62079268 is also more sensitive to rutting than the composition according to the invention.

Preferably factory-prepared 1009695-4 penetration bitumen is used in the composition according to the invention.

Preferably, the polymer coating is applied to the particles with a diameter of <63 µm from an aqueous solution of a polymer, which polymer contains 5 monomer units containing carboxylic acid groups and / or anhydride groups, or a salt thereof. Mixtures of such polymers can also be used.

Preferably, the polymer coating is applied to the 10 particles with a diameter of <63 µm from an aqueous solution, characterized in that the polymer in the aqueous solution contains at least 10 mol% monomer units containing carboxylate anions. Even more preferably, the aqueous solution contains a polymer containing at least 20 mol%, even more preferably at least 30 mol% monomer units containing carboxylate anions. Examples of polymers that can be used in the aqueous solution are water-soluble styrene-maleic anhydride copolymer, water-soluble isobutylene-maleic anhydride copolymer, polyacrylic acid and water-soluble salts of such polymers. Preferably, the particles are coated from an aqueous solution of polyacrylic acid or an aqueous solution of a copolymer of styrene and maleic anhydride, preferably a copolymer of styrene and maleic anhydride containing at least 30 mol% maleic anhydride monomer units.

In this text, water-soluble polymers are understood to mean polymers which dissolve in an aqueous medium 1009695-5, which aqueous medium can be neutral and / or acid and / or basic. Preferably, copolymers containing monomer units of maleic anhydride dissolved in an aqueous solution of an alkali metal hydroxide are used.

The molecular weight of the polymer containing monomer units containing carboxylate anions in the solution can vary from, for example, 1000 g / mol to, for example, 500,000 g / mol.

Preferably, the particles with a diameter of less than 63 µm are coated with an aqueous solution of between 0.25 and 5% by weight of polymer, based on the weight of the dry particles. Even more preferably, the particles are coated with an aqueous solution of between 1 and 2.5% by weight of polymer, based on the weight of the dry particles.

It is possible that the composition according to the invention is carried out as a mortar. In a preferred embodiment of the composition according to the invention, it is characterized in that the composition contains mineral particles of which at least 75% has a diameter smaller than 63 / m. All fillers known for use in bitumen can be used in the composition according to the invention. Examples of fillers are stone meal, fly ash, lime hydrate, limestone meal. Fly ash or limestone flour or a mixture thereof is preferably used.

It is also possible to design the composition according to the invention as an asphalt. In addition to mineral particles with a particle diameter <63 1009695 - 6 - μτη, which particles are provided with a polymer coating, which coating is applied to the particles from an aqueous solution of a polymer, which polymer in the solution contains 5 monomer units containing carboxylate anions , particles are then present in the composition with a particle diameter> 63 μπι, which particles may or may not be provided with the polymer coating.

In a preferred embodiment, the composition according to the invention is characterized in that the composition contains an elastomer and / or a thermoplastic, suitable for reducing cracking. Although it is known per se that bitumen exhibits less cracking and less rutting when such elastomers or thermoplastics are added to the bitumen, however, by using the composition according to the invention even with much smaller amounts of the elastomer or of the elastomer. thermoplastic better properties are achieved than in the known compositions. Examples of such elastomers used in bitumen are styrene-butadiene copolymers (SB) or styrene-butadiene random copolymer (SBR) or styrene-butadiene-styrene-block copolymers (SBS), styrene-isoprene-styrene block copolymers (SIS) or ethylene-propylene-diene terpolymer (EPDM). Examples of such thermoplastics are atactic polypropylene (aPP), ethylene-vinyl acetate copolymers (EVA) and polyethylene (PE). The elastomers or thermoplastics are usually added to the bitumen in powder or granulate form, 100 P β 95 i - 7 - whereby a physical mixture is formed.

The composition according to the invention preferably contains SBS, aPP or EVA. The amount of SBS containing the composition according to the invention is preferably between 0.5 and 3.5% by weight, based on the amount of bitumen. The amount of EVA containing the composition according to the invention is preferably between 0.5 and 4% by weight, based on the amount of bitumen. The amount of aPP containing the composition according to the invention is preferably between 2.5 and 10% by weight, even more preferably between 4 and 6% by weight, based on the amount of bitumen. By using a composition according to the invention in the preparation of, for example, asphalt to which a thermoplastic or elastomer is added, a considerable saving in the cost of elastomers and / or thermoplastics can be achieved.

The invention also relates to a process for the preparation of the particles provided with the polymer coating, as used in the composition according to the invention. The method is characterized in that mineral particles with a particle diameter <63 μπι are contacted with an aqueous solution of a polymer, the polymer in the solution containing monomer units containing carboxylate anions, after which the aqueous solvent is removed. The particles obtained are provided with the polymer coating.

Preferably, the method is characterized in that the 10096 & 5-8 mass which is formed after removal of the solvent is ground and sieved into particles with a diameter <G3 / m.

The removal of the aqueous solvent can take place in various ways, for example by evaporation or by filtration.

In a preferred embodiment of the method of preparing particles coated with the polymer coating, the solvent is removed by evaporation. This has the advantage that all the polymer 10 which was present in the aqueous solution adheres very well to the mineral particles with a diameter <63 µm and thus a very good asphalt can be obtained.

The composition according to the invention can be obtained by mixing particles obtained by the process for the preparation of particles provided with a polymer coating with stirring and heating.

The invention will be illustrated by way of examples, without being limited thereto.

Examples and Comparative Experiments Example I

To 16.8 ml of a potassium hydroxide solution (KOH solution) in a beaker, which solution was prepared from 45 g KOH in 55 g demi water, 20 g of a copolymer containing 34 mol% monomer units maleic anhydride and 66 mol% monomer units styrene (SMA; Stapron S (TM) SZ34080 1009695 - 9 - from DSM of the Netherlands molecular weight 80,000 g / mol) were added, after which the resulting solution was supplemented with demineralised water to a total weight of 100 g. The solution was then heated and stirred at a temperature of 80 to 90 ° C until the polymer was completely dissolved.

A dilution was then made by supplementing 14.3 g of the polymer solution with demineralised water to a total weight of 100 g.

10 100 g Wigro 60k (a filler from the Company

Winterswijksche Steen- en Kalkgroeve B.V. from the Netherlands, typically having a composition of 65-75 mass% limestone flour and 25-35 mass% lime hydrate; bitumen number (min-max) = 56-62)) with a diameter smaller than 63 μπι, was contacted with 10 ml of the diluted aqueous polymer solution (2 wt% SMA with respect to the dry filler), after which another 20 ml of extra demi water was added. Then it was stirred with a spatula until a thick paste formed. The beaker with the paste was dried in a drying oven at a temperature of 80 to 90 ° C under a nitrogen atmosphere. The cake which was formed after drying was then finely ground with a ball mill, into particles with a diameter smaller than 63 µm.

A mixture of bitumen (type Esso 80/100 (penetration index 80/100) from Esso from the Netherlands) and of the coated filler particles (50/50 parts by volume) was heated to 150 ° C in a steel mixing beaker. The mixture was manually stirred with a spatula until it looked homogeneous, and then for at least three more minutes. The resulting mortar (bitumen 1009695 - 10 - + coated filler) was poured into a mold with a diameter of 15 mm and a height of 2.3 mm. A weight of about 3 kg was placed on the mold for 5 minutes to compact the mortar.

The mold was then placed in the refrigerator. The cooled mortar released easily from the mold.

The viscoelastic behavior (dynamic modulus as a function of frequency) of mold-preformed mortar was determined as described under "Rheological Measurements" using a rheometer, type RMS800, manufacturer Rheometrics. A flat plate geometry was used, with the flat plates having a diameter of 15 mm. The plates were heated to 50 ° C. The deformation was 0.2%. The results of the measurements are shown in Table 1.

Comparative Experiment A

100 g Wigro 60k (a filler from Firma 20 Winterswijksche Steen- en Kalkgroeve B.V. from

Netherlands,) with a diameter smaller than 63 µm was mixed with bitumen (type Esso 80/100), as described in example I.

The viscoelastic behavior of the mortar thus created was determined as described under example 1. The results of the measurements are shown in Table 1.

Comparative Experiment B 30 8.82 g bitumen (type Esso 80/100 (penetration index 80/100) from Esso from the Netherlands) was heated to 180-190 ° C, 1009635-11, whereby the bitumen melted. To the molten bitumen, while stirring with a propeller stirrer, 0.18 g of SMA containing 34 mol% monomer units of maleic anhydride and 66 mol% monomer units of styrene (mol weight 80,000 g / mol) was added. After about 45 minutes, the SMA had melted. Stirring was then continued for at least 1 hour.

Then Wigro 60 K (without polymer coating) was added to the bitumen / SMA mixture at 150 [deg.] C. (50/05 parts by volume). The mixture was stirred manually with a spatula until it looked homogeneous, and then for at least three more minutes. The resulting mortar was poured into a mold with a diameter of 15 mm and a height of 2.3 mm. A weight of about 3 kg was placed on the mold for 5 minutes to compact the mortar. The mold was then placed in the refrigerator. The cooled mortar released easily from the mold.

The viscoelastic behavior of the mortar thus created was determined as described under example 1. The results of the measurements are shown in Table 1.

Example II

A mixture of bitumen and Stamyroid (TM) 43C (a mixture of atactic polypropylene with a small amount of isotactic polypropylene) from DSM from the Netherlands was prepared by 0.5 parts by weight Stamyroid 43C and 10 parts by weight Bitumen (Esso 80/100) at room temperature into a steel mixing cup. The mixture was heated to a temperature of 190 ° C with stirring. After the Stamyroid was distributed homogeneously in the bitumen, stirring was continued for at least another hour. The mass was poured into aluminum containers in aliquots of approx. 10 g and stored in the refrigerator.

As described in Example I, a mortar was prepared, but instead of pure bitumen, the above-described mixture of bitumen and Stamyroid C was used. The mixture of 50/50 parts by volume of the coated filler particles (2 wt% SMA polymer on the dry filler particles) and bitumen / Stamyroid 43C was heated to 150 ° C in a steel mixing beaker. The mixture was stirred manually with a spatula until it looked homogeneous, and then for at least three more minutes. The resulting mortar (polymer-coated filler and bitumen / Stamyroid 43C)) was poured into a mold with a diameter of 15 mm and a height of 2.3 mm. A weight of about 3 kg was placed on the mold for 5 minutes to compact the mortar. The mold was then placed in the refrigerator 20. The cooled mortar released easily from the mold.

The viscoelastic behavior of the resulting mortar was determined as described in example 1. The result of the measurements is shown in Table 1.

Veraeli-iend Experiment C

A mortar was prepared analogous to the procedure described in Example II. However, instead of filler particles with a polymer coating, filler particles without polymer coating were used.

10096 ^ 5 - 13 -

The obtained mortar was poured into a mold with a diameter of 15 mm and a height of 2.3 mm. A weight of about 3 kg was placed on the mold for 5 minutes to compact the mortar.

The mold was then placed in the refrigerator. The cooled mortar released easily from the mold.

The viscoelastic behavior of the resulting mortar was determined - as described in Example 1. The result of the measurements is shown in Table 1.

Comparative Experiment D

A mortar was prepared analogous to the method described in Comparative experiment C.

However, instead of a mixture of 0.5 parts by weight Stamyroid 43C and 10 parts by weight Bitumen (Esso 80/100), a mixture of 1 parts by weight Stamyroid and 10 parts by weight bitumen was prepared.

The obtained mortar was poured into a mold with a diameter of 15 mm and a height of 2.3 mm. A weight of about 3 kg was placed on the mold for 5 minutes to compact the mortar. The mold was then placed in the refrigerator. The cooled mortar released easily from the mold.

The viscoelastic behavior of the mortar thus created was determined as described in example 1. The result of the measurements is shown in Table 1.

30 Rheological measurements

The viscoelastic behavior of the 1009 β 95 - 14 different mortars was determined as using a rheometer, type RMS800, manufacturer Rheometrics. Flat plate geometry was used, the flat plates having a diameter of 15 mm. The plates were heated to 50 ° C. The deformation was 0.2%.

To compare compositions containing bitumen and a fraction of inorganic particles for trace behavior, the lowest temperature of each composition was determined at G * / sin (ö)> 10 kPa, at a measuring frequency of 1.6 Hz (10 rad / s). This method has been specially developed for rheological measurements on mortars and is described in described in "Effect of filler aggregate on Rheological Properties 15 of Mastic" - Molenaar, Voskuilen and Bothmer. Published in Proc. Int. RILEM Symp., 5th (1997) 101-108. The higher the measured temperature, the more insensitive the composition is for rail forming. The results of the measurements on the mortar compositions according to Examples 20 I and II and Comparative Experiments A to D are shown in Table 1.

TABLE 1

Composition T (in ° C) where G * / sin ((d)> 10 kPa i __ _. __

Example I 69

Comparative Experiment A 60.5

Comparative Experiment B 62.3

Example II "" 84

Comparative Experiment C 65.3

Comparative Experiment D 82 icopf'vfi - 15 -

Comparison of the temperature found for Comparative Experiment A and Comparative Experiment B shows that the direct addition of SMA 5 to bitumen results in a higher temperature for which G * / sin (ö)> 10 kPa. This means that composition A is less resistant to rutting than composition B. However, when comparing the results for Comparative Experiments A and B and Example I, it is clear that the composition contains those particles with a diameter <63 μπι on which the SMA is the polymer coating is applied, which is even less sensitive to rutting.

Comparison of found temperature for Comparative Experiment C and Comparative

Experiment D shows that adding twice as much Stamyroid 43C to the bitumen results in a higher temperature for which G * / sin (d)> 10 kPa. This means that composition D is much more resistant to rutting than composition C. However, when comparing the results for Comparative Experiments C and D and Example II, it is clear that the composition contains those particles with a diameter <63 μχη on which the polymer coating is still less sensitive to rutting.

1009695

Claims (20)

1. Composition containing bitumen and mineral particles, which particles are coated with a polymer, characterized in that the composition contains mineral particles with a particle diameter <63 μττι, which particles are provided with a polymer coating, which coating 10 on the particles is applied from an aqueous solution of a polymer, the polymer in the solution containing monomer units containing carboxylate anions. 2. A composition according to claim 1, characterized in that the polymer coating is applied to the particles with a diameter <63 μπι from an aqueous solution of a polymer, which polymer contains monomer units containing carboxylic acid groups and / or anhydride groups, or a salt thereof. Composition according to either of Claims 1 and 2, characterized in that the polymer in the aqueous solution contains at least 10 mol% monomer units containing carboxylate anions. Composition according to either of Claims 1 and 2, characterized in that the polymer in the aqueous solution contains at least 20 mol% monomer units containing carboxylate anions. Composition according to any one of Claims 1 to 30 with 4, characterized in that the particles are coated with an aqueous solution of polyacrylic acid 1008695-17 or an aqueous solution of a copolymer of styrene and maleic anhydride. Composition according to any one of claims 1 to 5 with 5, characterized in that copolymers containing monomer units maleic anhydride are dissolved in an aqueous solution of an alkali hydroxide. Composition according to any one of claims 1 to 10 with 6, characterized in that the particles of a diameter of less than 63 µm are coated with an aqueous solution of between 0.25 and 5% by weight of polymer, based on on the weight of the dry particles. The composition according to any one of claims 1 to 6, characterized in that the particles of a diameter smaller than 63 μπι are coated with an aqueous solution of between 1 and 2.5% by weight of polymer, based on the weight of the dry particles. The composition according to any one of claims 1 to 8, characterized in that the composition contains mineral particles of which at least 75% have a diameter smaller than 63µπι. 10. A composition according to any one of claims 1 to 9, characterized in that the mineral particles with a diameter <63 μπι fly ash or limestone flour or a mixture thereof. Composition according to any one of claims 1 to 10, characterized in that the composition contains a 1009695-18 elastomer and / or a thermoplastic. Composition according to claim 11, characterized in that the composition contains SBS, aPP or EVA. Composition according to claim 12, characterized in that the amount of SBS containing the composition is between 0.5 and 3.5% by weight, based on the amount of bitumen. 14. A composition according to claim 12, characterized in that the amount of EVA containing the composition is between 0.5 and 4% by weight, based on the amount of bitumen. 15. A composition according to claim 12, characterized in that the amount of aPP containing the composition is between 2.5 and 10% by weight, based on the amount of bitumen. A composition according to claim 12, characterized in that the amount of aPP containing the composition is between 4 and 6% by weight, based on the amount of bitumen. 17. Process for the preparation of particles provided with the polymer coating, as used in the composition according to any one of claims 1-16, characterized in that mineral particles with a particle diameter <63 μχα are brought into contact with an aqueous solution. of a polymer, which polymer contains monomer units in the solution containing carboxylate anions, after which the aqueous solvent is removed. Process according to claim 17, characterized in 1009695 # - 19 - that the mass formed after removal of the solvent is ground and sieved into particles with a diameter of <63µπι. A method according to any one of claims 17 or 18, 5, characterized in that the solvent is removed by evaporation. Use of particles provided with a polymer coating according to any one of claims 17 to 19, in a composition containing 10 bitumen. t 100 9 6 ö5 COOPERATION TREATY (PCT) REPORT ON NEWNESS RESEARCH OF INTERNATIONAL TYPE ION IDENTIFICATION OF THE NATIONAL APPLICATION Characteristic of the applicant or of the authorized representative 9359 NL Dutch filing date 1009695 20 July 1998 Priority date (name) DSM applicant Date of the request for an examination of international type Awarded by the International Research Authority (ISA) to the application for an examination of international type No SN 31517 EN I. CLASSIFICATION OF THE SUBJECT (where different classifications apply, all classification symbols specify) According to International Classification (IPC) Int.Cl.6: C 08 K 9/08, C 04 B 20/10, C 08 L 95/00 II. FIELDS OF TECHNIQUE EXAMINED Minimum documentation examined _ Classification system _ Classification symbols Int. CERTAIN CONCLUSIONS (comments on supplement sheet) IV- 1 1 LACK OF UNITY OF INVENTION (comments on supplement sheet) 7 f 'Porm PCT / ISA / 20H *! 07.1979