DE10013465A1 - Bitumen or asphalt, useful for road dressing, contains high molecular weight polyolefin decomposition wax prepared by thermal decomposition of the polyolefin fraction of recycled plastics - Google Patents

Abstract

Bitumen or asphalt contains a high molecular weight polyolefin decomposition wax prepared by thermal decomposition of the polyolefin fraction of recycled plastics under the exclusion of oxygen with distillative separation of the gaseous and liquid hydrocarbons from the remaining non-volatile residue and reduction of the residual ash content to less than 5(2) wt. %. Independent claims are included for (i) a process for the production of asphalt by addition of the polyolefin wax (I) before or simultaneously with the addition of other additive such as sand, gravel or chippings and bitumen. (ii) a road covering comprising asphalt or bitumen comprising a base layer, binder layer and/or top layer containing the polyolefin wax (I).

Description

The invention relates to polyolefin degradation waxes from recycling plastics as additives to improve the own bitumen and asphalt in road construction.

It is already known to add bitumen by adding thermoplastics in its heat resistance and through the addition of elastomes to improve its cold flexibility. So z. B. Styrene-butadiene-styrene (SBS) and atactic polypropylene (APP) found wide application in the roofing membrane area.

Basically, TL-PmB 89, Part 1 distinguishes the following ready-to-use polymer modified bitumens for use in road construction:

• - Bitumen A modified with elastomer
• - Elastomer modified bitumen B
• - Thermoplastic modified bitumen C.

While the use of styrene-butadiene-styrene in road construction or styrene-butadiene-modified bitumens Gaining importance and products of this kind by almost everyone Petroleum companies sold are thermoplastic modified group C bitumens and combinations of elastomer-modified and thermoplastic-modified bitumens  So far, little has been used in road construction. At the On the one hand, the use of such combinations could beneficial effect of elastomer-modified bitumens on the in Road construction important cold properties, on the other hand the improved heat resistance modifi by adding thermoplastic decorated bitumens can be used.

From DE 44 44 752 it is already known that amorphous Thermoplastic based on polyolefins in an amount of about 7 wt .-% are added to the road bitumen at 180 ° C. can. The thermoplastic is stored finely dispersed in the Malt phase on and is swollen at the particle edges. According to the manufacturer, this storage leads lers / suppliers to change the rheological Properties of the bitumen, which are mainly in one Increasing the softening point and reducing the Penetration expresses. The ductility remains practically unchanged changes. To counteract the thermo-oxidative degradation at the To protect processing, the thermoplastics are usually equipped with stabilizers. Still, for longer Exposure to high temperatures and oxygen Decrease in molecular weight take place.

It has also been reported that the Add suitable waxes to bitumen or asphalt Application properties can be influenced. So is It has been reported that raw montan wax is added as an additive Bitumen the workability and the application technology Properties of the asphalt mixes made from it can improve. In particular, the advantages of Lowering the processing temperatures while increasing the Stability to reduce the ruts and on the Possibility of paving asphalt even at deeper ones Outside temperatures noted. In addition, the liability of the  Bitumen on mineral aggregates such as grit ver be improved.

Furthermore, DE 198 38 770 bitumens and asphalts described for the production of road surface, which is characterized by Addition of obtained by a Fischer-Tropsch synthesis Mark paraffin. Instead of the term Fischer-Tropsch- Paraffins are also sometimes the terms hard waxes and Hard paraffins or macrocrystalline paraffins are used. Fischer-Tropsch paraffins consist primarily of normal Paraffins. More than 90% are usually n-alkanes and the rest iso-alkanes. The freezing point of the Fischer-Tropsch paraffins is around 68 to 105 ° C. The amounts added to bitumen are between 0.5 and 10%.

DE 198 38 770 also describes how the addition of the Fischer-Tropsch paraffin in amounts of 2.5%, 5% and 7.5% to a bitumen of grade B 100, its properties influenced. The penetration (ÖNORM C 9214) increases 89 down to 41. At the same time, the Fraass breaking point rises (ÖNORM C 9213) from -14.5 to -10 ° C. Thereby the Erwei takes point (ÖNORM C 9212) from 44.5 to 101 ° C if a Fischer-Tropsch paraffin from C40 to C60 is used. At the same time, as a result of the improved flow behavior by adding Fischer-Tropsch paraffin the Verdich willingness to asphalt improved. They too Installation times prolonged and it can be deeper outside temperatures are worked. In addition, by the Add Fischer-Tropsch paraffin to mastic asphalt one Fixed reduction in installation temperature by up to 30 ° C to deliver. Finally, it is also reported that an addition from 3% Fischer-Tropsch paraffin to a stone mastic asphalt the groove depth at 50 ° C and 20,000 rollovers of 5.7 mm reduced to 2.2 mm.  

Tests with the bitumen qualities of types B 45, B 65 and B 80, each with 4% and 6% Fischer-Tropsch paraffin the same results were obtained. The Plasticity range (difference between softening point and Refraction point according to Fraass) could be improved considerably, the Fraass breaking point is only slightly a Binder level shifts.

In the German patent application filed at the same time . . . (internal file number B 56 P 1) describes that the there mentioned high molecular weight polyolefin degradation waxes which thermal degradation of the polyolefin fraction from recycling Plastics are obtained, also in bitumen and asphalt can be used. Subject of the present Registration is therefore application-specific for these mining waxes to develop fish in such a way that a resource-saving and high quality use in asphalt and road construction becomes possible.

This task is solved by bitumens and / or asphalt, by adding a high molecular weight polyolefin degradation wax can be produced in the thermal degradation of the polyolefin Fraction of recycled plastics in the absence of oxygen and distillative removal of the resulting gaseous and liquid hydrocarbons from the remaining, not evaporable residue and reduction in the residual ash content to an amount of less than 5 percent by weight, preferably until less than 2 percent by weight is formed.

Investigations with polyolefin degradation waxes with average molecular weights of around 1,200, 4,500 and 8,500 were carried out. The polyolefin degradation waxes used are largely freed from paraffin parts consisting of gases, oils and low molecular paraffin waxes with carbon chains shorter than about C ₅₀ by distillation, since it could be shown that a wax with an average molecular weight of about 4,500, which contains paraffinic components with carbon chains below about C ₅₀ still contained in the lane formation test according to TPA-StB 1997 edition shows the so-called slow-setting effect, ie leads to damage to the asphalt layer. In contrast, there is no slow-setting effect if the paraffin parts with carbon chains below about C _{50 have been separated} from the polyolefin degradation wax.

To determine the property improvements in a bitumen of class B 65, polyolefin degradation waxes with average molar masses of approximately 1,200, 4,500 and 8,500 were added in amounts of 5 percent by weight and test specimens were produced therefrom. These test specimens were exposed to a load of 25 N in a water bath at 30 ° C. with a 5 cm ² punch and the depression in mm was determined over the load time. It was found that the degradation wax with an average molecular weight of about 8,500, which had been freed of all paraffinic components with carbon chains below about C ₅₀ , gave the best results. In addition to the higher average molecular weight, this product also had a higher crystallinity than the other polyolefin degradation waxes. The degree of crystallinity increases from an average molecular weight of 1,200 to 8,500 from 40% to 55%. Therefore, the polyol fin degradation wax with an average molecular weight of 8,500 was used for the further experiments.

Table I shows the tests on bitumen, which with Modified polyolefin degradation wax from recycled plastics has been:  

Table I

Table I shows that an addition of 5% of the above Polyolefin degradation wax to a B 65 to reduce the Needle penetration (DIN 52010) leads from 55 to 28 × 1/10 mm. The softening point (DIN 52011) is determined by the addition of wax raised by 10 ° C, so that in this application example a Increasing the plasticity range by 10 ° C is achieved. This The result is all the more positive than the breaking point according to Fraass, there is no negative change and the down The temperature behavior of the bitumen is completely preserved remains. Other application examples with soft bitumen types, for example a B 80, result in higher values in the lowering penetration and raising the softening point. As The result of this series of experiments shows that with the Wax additive from softer types of bitumen, for example B 100 or B 80, harder types of bitumen, for example B 65 or B 45, can be produced.  

The effects of mixing time and mixing temperature are in Table II using the example of a mixture of 95% bitumen B65 with 5% polyolefin degradation wax shown:

Table II

It shows that an increase in mixing time and mixing temperature almost no influence on the solidification point (DIN 52011). That is why the wax can already be used mix into the basic bitumen for a short time.

Another important criterion is the adhesive property of the bitumen modified on the rock with the wax. The attempts were made according to Dr. Potschka performed.

Table III shows the most important results using the example a blend of 95% B65 with 5% polyolefin degradation wax compiled:

Table III

While with conventional road construction bitumens the adhesion limit Viscosities for quartzite between 4 and 5 could with the addition of wax to a B 65 achieves a value of 7. Thus the addition of wax results in an improvement in Rock adhesion.

Table IV shows the test results on one Asphalt back extracted binder. It became their own of a Stan offset with the asphalt binder 0/16 dardbitumen B 65 compared to a bitumen, the additional 3% polyolefin degradation wax were still added.

Table IV

The results show that the positive properties, which is achieved by adding the polyolefin degradation wax such as needle penetration and softening point (ring + ball ° C) also in the extracted binder find again. The Fraass breaking points also show on extracted binder with added wax even cheaper Values as on the extracted binder without wax, what the good cold properties of the wax additive again underlines.  

The properties of asphalt mixtures to which the polyolefin degradation wax according to the invention had been added were then investigated. One of the most important properties for the effect of wax additives on asphalt and bitumen was the track formation test according to TPA-StB, 1997 edition. The test plates required for the track formation test were produced with a segment compressor. Since a path-controlled compaction was chosen, the degree of compaction could be specified via the reference space density of the Marshall test and the mix weight (here 100%). The test panels were made with a thickness of 8 cm. Table V shows the results of the track formation tests on different asphalt mixes:

The results show that the depth of the ruts through the Addition of the polyolefin degradation wax according to the invention improved has been. There were average values of 1.72 mm at one Mixture of B 65 with 5% wax and an asphalt binder 0/22-DS and 2.41 mm with a wax addition of 3% with an asphalt bin the 0/16 determined. The reference value without the addition of the polyol finabbauwachses with 3% wax addition and an asphalt binder 0/16 2.86.

Table VI shows the influence of the addition of wax on the Compactibility of the mix with and without the addition of 3% Polyolefin degradation wax shown. The results show that the spatial density is increased by the addition of wax and the voids can be reduced.

Table VI

The excellent cold properties of the polyols Bituminous wax modified can be used on the transferred asphalt samples transferred. The asphalt binder 0/16 with B 65 was with and without the addition of the polyolefin degradation wax subjected to a test of the cold bending tensile strength. The Results are shown in Table VII:  

Table VII

The sample made with the addition of polyolefin degradation waxes then has a higher bending tensile strength and shows at -20 ° C only a very slight difference to that at 0 ° C value obtained. In addition to tests in rotating Pistons according to DIN 52016 were also further aging tests carried out with the model pot process. It was on Material quantities of 3 kg basalt chips 8/11 mm and 1.5 GT Binder used. The model pot consists of an electrically heated pot with external wall insulation and Perforated plate to which the mix is loosely applied. It an oxidative aging over one hour in a Air flow of 500 ml / min. performed at 140 ° C. As well a distillative aging with 500 ml / min. Nitrogen at 140 ° C carried out. Both attempts are compared with containing a B 65 binder and a B 65 binder the polyolefin degradation wax performed. The results showed that the observed increases in the softening points of Mixtures with the wax are comparable to the mixtures without added wax. Even the measurement of the resulting Ductility and breakpoints according to Fraass showed no negative Characteristics.

Claims (14)

1. Bitumen or asphalt, characterized by a portion of a high molecular weight polyolefin degradation wax, which during thermal degradation of the polyolefin fraction of recycling plastics with exclusion of oxygen and distillative removal of the resulting gaseous and liquid hydrocarbons from the remaining, non-evaporable residue and reduction of the residual ash content down to a lot of less than 5 weight percent, preferably up to less than 2 weight percent. 2. Bitumen or asphalt according to claim 1, characterized records that the polyolefin degradation wax has a medium molecular weight above 7,500, preferably above 8,500. 3. Bitumen or asphalt according to claims 1 and 2, characterized characterized that the radiographically determined Crystallinity of the polyolefin degradation wax over 50%, preferred wise is over 55%. 4. bitumen or asphalt according to claims 1 to 3, characterized characterized that from the polyolefin degradation wax paraffinic portions with up to about 50 carbon atoms have been distilled off. 5. bitumen or asphalt according to claims 1 to 4, characterized characterized that the softening point of polyolefin degradation wax above 90 ° C, preferably above 98 ° C lies.   6. bitumen or asphalt according to claims 1 to 5, characterized characterized in that the penetration measured at 20 ° C, 100 g and 5 sec. under 5 × 1/10 mm, preferably under 3 × 1/10 mm lies. 7. Bitumen for road construction, characterized in that it the polyolefin degradation wax of claims 1 to 6 in quantities from 1 to 10 percent by weight, preferably in amounts of 3 to Contains 6 percent by weight. 8. bitumen for road construction according to claim 7, characterized characterized in that it also contains styrene-butadiene polymers in amounts of 1 to 5 percent by weight, preferably in amounts contains from 1 to 3 percent by weight. 9. bitumen for road construction according to claims 7 and 8, characterized in that its viscosity by the addition of the polyolefin degradation wax in the temperature range between 110 is reduced to 180 ° C. 10. Process for the production of asphalt according to the claims 1 to 6, characterized in that the polyolefin degradation wax the asphalt mixture before or simultaneously with its ver mix with additives such as sand, gravel or grit and is added to the bitumen. 11. Use of polyolefin degradation waxes according to An Proverbs 1 to 5 to increase the hardness and decrease the Towing tendency of asphalt. 12. Use of the polyolefin degradation waxes according to the claims 1 to 5 to improve the compressibility and reduction the void content of asphalt.   13. Use of the polyolefin degradation waxes of claims 1 to 5 to reduce the processing temperature of asphalt. 14. Road surface from the asphalt or bitumen of the claims 1 to 9, characterized in that both base course and / or binding layer and / or top layer using a polyolefin degradation wax according to claims 1 to 5 have been produced.