EP0049485A1 - Coating, method for its production and its use - Google Patents

Abstract

A covering especially for roads consisting of mineral fillers, reclaimed rubber and a binder based on bitumen, it being possible to incorporate 5 to 30% by weight of reclaimed rubber and the binder comprising a hot-homogenized blend of bitumen and thermoplastic polymers, especially of the radial teleblock copolymer type being used. The resultant coverings are capable of reducing the annoyance caused by rolling noises etc. without the necessity of putting up with losses of other qualities.

Description

The invention is a novel covering, especially _S traßenbelag consisting of mineral fillers, Gummiregeneraten and a binder based on bitumen. Furthermore, the invention relates to a method for producing this covering and its use for sound absorption, in particular of roadways.

The fight against noise, especially traffic noise, plays an important role in the fight against environmental pollution. The construction of noise barriers and noise barriers on the edge of busy roads near residential areas is one of these measures. On the other hand, it would be less time-consuming and more sensible to reduce traffic noise. Even if the engine and driving wind noise of motor vehicles are significantly reduced, there is still a significant noise pollution from the rolling noise. It is therefore an object of the present invention to develop a covering for the carriageways which reduces the formation of the rolling noises and does little reflecting the other driving noises and swallows them to a considerable extent. It was to be expected that road surfaces made of elastic asphalt with a significant proportion of elastomeric substances could be suitable for achieving noise abatement at the source. However, such a noise-reducing cover layer must meet all requirements of the traffic load and other conditions.

It is known that old tires are another environmental burden. Some of the old tires are therefore processed into granular or thread-like regenerates and some are used again in tire production. They are too Several attempts have been described to incorporate such rubber rain rates in asphalt surfaces, but it has never been possible to incorporate larger amounts than 3-5% of these rubber rain rates into these surfaces without the mechanical properties of the road surfaces having suffered unbearably.

A further object of the present invention was therefore to introduce rubber rain rates in a percentage higher than 5% in road surfaces, without the quality of these road surfaces thereby being impaired. From DE-OS 21 19 178 it is known to mix the filler and binder after heating rubber vulcanizate particles in order to adhere to the heated rock particles as a result of partial thermal change or decomposition. Already this addition of a total of 3% by weight of thread-like and powdery rubber vulcanizate leads to deteriorated properties of the pavement. It is still claimed that it has proven expedient to pretreat the thread-like rubber material with a substance to increase the adhesiveness. However, it is not specified which substances could be suitable for this. From DE-OS 21 46 9O2 it is known to mix the bitumen or asphalt with polypropylene, which is intended to increase the adhesive properties, toughness and breaking strength of the covering. The proportion of polypropylene should be 1-8, preferably 3-6% by weight. Mixing the polypropylene with the bitumen is extremely difficult and therefore requires complex special equipment. This method has therefore no meaning in practice.

DE-OS 22 53 495 describes a process for producing a covering layer in which a mixture of grit and bituminous binder is applied to the substructure and this supporting structure is then solidified by mortar penetrating into the cavities, in which fillers or elastomers stiffening the bituminous binder be added. Rubber, vinyl polymers and the like can be considered as elastomers. These materials are particularly suitable for sealing coverings, but do not fulfill the above-mentioned tasks of utilizing high amounts of rubber regeneration and having a sound-absorbing effect.

From DE-AS 24 18 977 a method for producing a material consisting of mineral, polymer and bituminous components has become known, in which the polymer components can be comminuted thermoplastic polymers of various origins. Since it is a question of thermoplastic polymers, processing is relatively easy, but only 60-100% by weight of bitumen, based on the weight of the polymeric constituents, may be added to this mixture. Rubber rain rates cannot be processed here. Due to the relatively expensive starting materials, this process can only be used to a limited extent and for special purposes.

In an article in GAK 1977 - pages 842 to 847, R. Delme proposed the modification of bitumen with radial teleblock elastomers, although he points out that only some types of bitumen appear suitable. He further describes that in the laboratory these teleblock copolymers could be mixed with the bitumen within three to five hours using a propeller stirrer at 180 °. In large tech niche scale, the mixing is to be carried out in horizontally arranged sigma mixers, as is customary in bitumen processing. The mixing process should always be carried out at 180 ° C, as the polymer degrades at higher temperatures. Mixing units with high shear forces should be used for shorter mixing cycles. Oxidized bitumen is not compatible with thermoplastic styrene-butadiene rubbers, so that only individual types of oxidized bitumen can be satisfactorily modified with the teleblock copolymers. While Delme recommends the modification of bitumen with radial teleblock elastomers for various areas of application, such as bitumen felt panels, joint seals, noise insulation and underbody protection in the automotive industry, as well as pipelines and underground cables, he makes repeated attempts to modify bitumen for road construction with rubber additives , as disappointing. So far, the difficulties and increased costs of mixing bitumen with rubbers have not been justified by a corresponding quality improvement.

It has now surprisingly been found that a binder based on bitumen, which contains 5-25% radial teleblock copolymers, these having to be hot homogenized with the bitumen, is suitable for absorbing 5-30% rubber regeneration in addition to mineral fillers and leads to coverings, especially road coverings, that meet all quality requirements. In addition, it was found that these coverings are suitable for supporting noise control at the source by reducing the rolling noise and also less the engine and driving wind be reflected in noise and swallowed instead.

Copolymers of butadiene and styrene in a ratio of 75/25 to 60/40 with a molecular weight of 50,000-600,000 have proven particularly useful as radial teleblock copolymers.

All distilled standard bitumens of classes B 25 - B 200 are particularly suitable as bitumen. These bitumen qualities are compatible with the radial teleblock copolymers and can be homogenized at temperatures of 180 - 220 ° C, preferably 180 - 200 ° C, within 0.3 - 2 hours in a high-speed mixer. In these polymer-modified binders, the rubber regeneration and minerals can be mixed in the usual way, it has proven useful to preheat the minerals and add the rubber regeneration at room temperature. The mixtures obtained in this way are processed further to the covering in a manner known per se. In order to be able to hot-homogenize bitumen and the radial teleblock copolymers, high-speed mixers are required, rotor-stator systems in particular having proven themselves.

Due to their good properties, the new coverings are particularly suitable as road coverings, from which a high level of sound absorption is expected. Due to the good mechanical properties, they can also be used for bridge plates in all-steel construction (orthotropic plates), as described for example in DE-OS 23 04 004. Furthermore, these coverings can be used for schoolyards, aircraft taxiways etc., since it has been found that the compatible components bitumen and radial teleblock Copolymers according to the invention are capable of absorbing and binding the most diverse types of mineral fillers and the most varied amounts of rubber regeneration when hot homogenized. It therefore depends on the respective intended use which bitumen quality is modified with the radial teleblock copolymers and then mixed with the desired amount of rubber regenerates and minerals to form a covering.

A great advantage of the process according to the invention is that the uneconomically long mixing times in the temperature range of 180-220 ° C. can be kept short, namely 0.3-2 hours, preferably 0.8-1.5 hours. Longer mixing times are not only uneconomical, they also change the bitumen and the copolymer negatively. The bitumen hardens and the copolymers are negatively changed by chain breakage.

The process according to the invention can be carried out either batchwise or continuously. By connecting several rotor-stator system mixers in series, the mixing time can be shortened further if desired. It is crucial that there is sufficient homogenization.

The invention is explained in more detail in the following examples. The surprisingly good properties of the coverings according to the invention, in comparison to conventional products and production processes, are evident from the comparative tests.

example 1

• a) In Anlehnung an die DIN-Norm 53504 und ASTM D 412, Typ Die A, wird die Kraftaufnahme F max bei Dehnung bis 300 % gemessen und ergibt 1,9.N. Die bleibende Dehnung nach 24 Stunden beträgt 12 %.
• b) Nach DIN 1995 beträgt der Erweichungspunkt (RuK) 110°C und der Brechpunkt (Fraaß) -43°C.
• c) Die Fließlänge nach 24 Stunden bei 80°C beträgt 8 mm.

In a device combination consisting of a conventional bitumen pump and a rotor-stator system mixer, 3 t of polymer-modified bitumen are produced by using 2.55 t of bitumen B 200 and 0.45 t of radial teleblock copolymer (butadiene -Styrene ratio 70/30, trade name Solprene 411, manufactured by Phillips Petroleum Company, USA, molecular weight 300,000) at 190 ° C. for 60 minutes. The engine output was 7.5 kW at 3,000 rpm. A sample of this binder is examined and gives the following properties:

• a) Based on the DIN standard 53504 and ASTM D 412, type Die A, the force absorption F max is measured at elongation up to 300% and results in 1.9.N. The permanent stretch after 24 hours is 12%.
• b) According to DIN 1995, the softening point (RuK) is 110 ° C and the breaking point (Fraass) is -43 ° C.
• c) The flow length after 24 hours at 80 ° C is 8 mm.

Example 2

• Erweichungspunkt (RuK) 99°C,
• Brechpunkt (Fraaß) -39°C,
• Fließlänge nach 24 Stunden bei 80°C llmm.

In a manner analogous to that described in Example 1, 3 t of polymer-modified bitumen are produced from 2.7 t of bitumen B 80 and 0.3 t of radial teleblock copolymer (Solpren 411). The mixing temperature is 200 ⁰ , the mixing time is 1 hour. The tested properties of a sample gave force absorption F max with an elongation of up to 300% 3.67 N, permanent elongation after 24 hours 10%,

• Softening point (RuK) 99 ° C,
• Breaking point (Fraass) -39 ° C,
• Flow length after 24 hours at 80 ° C llmm.

Example 3

• Kraftaufnahme F max bei Dehnung bis 300 % 10,1 N,
• bleibende Dehnung nach 24 Stunden 12 %,
• Erweichungspunkt (RuK) 98°C,
• Brechpunkt (Fraaß) -30°C,
• Fließlänge nach 24 Stunden bei 80°C 6 mm.

In a manner analogous to that described in Example 1, a polymer-modified binder is produced from 90% bitumen B 45 and 10% radial teleblock copolymer (Solpren 411). The mixing temperature during a 1 hour period is 200 ° C. The properties tested are:

• Force absorption F max with elongation up to 300% 10.1 N,
• permanent elongation after 24 hours 12%,
• Softening point (RuK) 98 ° C,
• Breaking point (Fraass) -30 ° C,
• Flow length after 24 hours at 80 ° C 6 mm.

Microscopic examination of the final samples with those taken before or after showed that after 30 minutes extensive homogenization took place, which increases only slightly over the next 1/2 hour and then remains practically constant. Good homogenization can be recognized by the structure of a network structure in which the bitumen parts are evenly enclosed by the copolymers. These homogenized binders produced on an industrial scale correspond entirely to the best homogenized mixtures that can be produced on a laboratory scale.

Example 4

In an analogous manner to that described in Example 3, 3 t of binders are produced from 90% bitumen B 200 or bitumen B 80 and 5% of the radial teleblock copolymers (Solpren 411 and Solpren 1205, butadiene-styrene ratio 75/25, molecular weight) 140,000). The mixing temperature was 190 and 200 °, respectively, the mixing time was 1 hour. Homogenization after 1 hour was complete in both cases. The other measured values for the softening point were 94 and 99 ° C, respectively. The breaking points (Fraass) -35 and -38 ° C. F max (N) was 1.25 and 3.67 and the permanent elongation after 24 hours was 18 and 10 mm.

From these two binders following recipes were ^- made:

These mixtures were mixed in a large asphalt mixing plant _- at approx. 200 ° C, the binder temperature being 175 ° C - 200 ° C, the rock temperature 220 ° C - 240 ° C, the mixture temperature 180 ° C _- 200 ° C while the rubber regeneration was added at air temperature (approx. 18 ⁰ ).

A device was installed on the feed line to the binder scales, which allowed the binder to be pumped directly into the weighing device. In addition, the elevator was prepared for the filling task in such a way that the rubber regeneration of the binding agent-mineral mixture could be added via a special weighing. The finished mixtures were partly poured into measuring plates measuring 50 x 50 x 4 cm and compacted under the support of a wooden plate using a vibrating roller, and in some cases they were also used to install a surface covering a road surface of approx. 40 m in length and approx. 3.75 m in width applied with the help of a road paver, these road surfaces were previously milled 4 cm deep. A VAT adhesive S was sprayed onto the milled surface in an amount of approx. 1 kg / m ² and then the asphalt was applied with the paver (ABG-Titan 350 S).

Example 5

In a manner analogous to that described in Example 4, a mixture of 20% polymer-modified binder (bitumen B 80) with 35% by weight of fine chippings 2/5 mm and 25% by weight of fine chippings 5/8 mm and 20% by weight % Rubber regeneration 5/8 mm mixed. The binder temperature was 200 ° C, the rock temperature 240 ° C, the mixed material temperature 190-200 C and the temperature of the rubber regenerate (air temperature) approx. 25 ° C. A polyurethane pressure-sensitive adhesive (Kleiberit R 217.1) was used as the adhesive for gluing the covering to the base. The job with the paver was done with full vibration of the screed. A cross profile measurement, a grip measurement with a pendulum device and comparative sound measurements were carried out on this surface. Installation errors on the surface could only be eliminated above a temperature of approx. 170 ° C, because the elastic asphalt cannot be processed due to the high viscosity of the binder. Such bumps can be corrected by means of electrically heated steel plates.

Other samples were made with other bitumen-based adhesives, namely Fina adhesive bridge emulsion, Tego adhesive bridge emulsion, Tego-Promak pressure sensitive adhesive E and Tego-Promak pressure sensitive adhesive. made over F. The best results were achieved with the Kleiberit R pressure-sensitive adhesive 217.1 polyurethane adhesive.

The transverse profile measurement on the test pavement of a heavily used road showed that within 30 days the difference was not more than 0.1 to 0.3 mm at two different points. The grip measurement with the pendulum device was carried out according to "Work instructions for combined grip and roughness measurement with the pendulum device and the flow meter ", Research Society for Roads, 1972 edition. The results were considerably better than the values of a comparable asphalt concrete 0/8.

Comparative sound measurements on the surface according to the invention compared to conventional surfaces showed that the surface according to the invention significantly reduces the frequencies above 800 Hz, not only by lower rolling noise at different speeds, but also by swallowing the sound from the other driving noises and Engine noise comes from. The reduction in noise was dependent on the speed (50 - 90 km / h) and the switching on and off of the motor during the measurement DL = 1 to 10 dB (A), especially in the high-frequency range from 1000 to 6000 _Hz . Comparative experiment 1

Test mixture with rubber regeneration and standard bitumen. Our own experiments with 3 - 5% rubber regeneration in bituminous asphalt mixtures showed that the rolling noise caused by vehicles is practically unchanged. Higher percentages of rubber regenerate led to poor processability and very poor solid incorporation. This result was found at different quantities, different temperatures, different bitumen types and different grain sizes of the mineral aggregates.

Comparative experiment 2

Test mixture with rubber regeneration, standard bitumen and additives of various polymeric substances. Mixing asphalt and adding "Pulvatex" (natural rubber) to the standard bitumen resulted in improved mechanical properties compared to the previous one without using a rubber regenerator conventional asphalt mixtures, however, this does not lead to better integration of rubber regeneration. Corresponding tests with the addition of "Cariphalt" (bitumen-rubber mixture) to the standard bitumen gave an improved resilience behavior, but a higher addition of rubber regenerate caused a considerable deterioration of the abrasion and the integration of the rubber regenerate.

Corresponding tests with "Baypren" (synthetic rubber) for standard bitumen also led to products with greatly deteriorated abrasion.

Asphalt mixtures with variable additions of "SBR-Latex" also showed no improvement in the abrasion values compared to other additives. Experiments with the adhesive "coumarone indene resin", which according to the manufacturer has a high temperature and thermal shock resistance, showed a relatively strong increase in the softening point (RuK). This addition also increases the splitting tensile strength of test specimens from asphalt mixtures, but only with very small additions of rubber regenerate. Elastic and rolling noise reducing and at the same time stable pavement ceilings cannot be produced with this.

Claims (5)

l. Covering, in particular road covering, consisting of mineral fillers, rubber regeneration agents and a binder based on bitumen, characterized in that the rubber regeneration content is 5-30% and the binder consists of a hot homogenized mixture of bitumen and thermoplastic polymers, preferably radial teleblock Copolymers, in a ratio of 95/5 to 75/25. 2. Covering according to claim 1, characterized in that the thermoplastic polymers are butadiene-styrene copolymers, in particular radial teleblock copolymers of butadiene and styrene in a ratio of 75/25 to 60/40 with a molecular weight of 50,000-600,000. 3. Process for the production of pavement, in particular road surface, according to claims 1 and 2, characterized in that the bitumen and the thermopla polymers at temperatures of 180 - 220 ° C within 0.3 - 2 hours in a high-speed mixer. Homogenized, then mixed with the rubber regenerates and preferably preheated minerals and then further processed in a manner known per se to form a coating. 4. The method according to claim 3, characterized in that a combination of a bitumen pump and a rotor-stator system is used as the high-speed mixer. 5. Use of coverings according to claims 1 and 2 for sound absorption, in particular of roadways.