DE3632709C2 - - Google Patents

Description

The invention relates to a method for Stabilization of mixtures of coal tar pitch and petroleum bitumen.

Mixtures of this type are used in road construction Binder used. One such binder is known for example from DE-PS 26 23 574. It consists of 80 to 65% by weight of petroleum bitumen and 20 up to 35% by weight from a plasticized Coal tar pitch. The bitumen should be highly aromatic with an asphalt content of at least 20% and a penetration between 10 and 50 · 1/10 mm. The plasticized coal tar pitch consists of 50 to 80 % By weight of a coal tar pitch with a Softening point (Kraemer-Sarnow) from 40 to 75 ° C and 50 to 20% by weight of a crystal-rich, between 350 and 450 ° C boiling coal tar fraction, and should no longer contain insoluble in toluene than 12%. The binder has turned out to be special  suitable for making more durable Road cover layers for heavily loaded roads proven (Petroleum and Coal, 1977, pp. 259 and 260).

A disadvantage of this known binder is, however, that only plasticized pitches with a low content of toluene insoluble can be used. At higher toluene insoluble contents occurs at the Hot storage a spontaneous settling of solid Ingredients on what causes malfunctions, namely to reduce the capacity of the Storage container and clogging of their drain pipe leads. This phenomenon is well known. So in the DE-PS 10 09 338 noted that for this Do not bind the coal tar pitch cracking conditions obtained from the coal tar may be, because its bitumen compatibility so much is lower, the higher the content of high molecular weight soot-like compounds (insoluble in toluene). Therefore, the content of tar-bitumen mixtures Toluene insoluble in tar limited to 10% (Georgg: Bitumen + tar, Rudolf Müller publishing company (1963), p. 136). Removing fixed Contamination from pitches is very complex and therefore unsuitable for road construction binders. The Pitch contamination does not reduce that Binding ability of the mixture still the stability of the road surface produced with it, but the mentioned Malfunctions are so serious that the Scope and the possible exploitation of the available coal tar pitch resources be restricted.  

The object of the invention is that Coal tar pitch base for the mixtures mentioned expand by finding suitable procedures for Stabilization of the Coal tar pitch-bitumen mixtures.  

The task is solved in that the Coal tar pitch before adding the Bitumen with aromatic hydrocarbon resins of Indene type or one containing these resins technical product is mixed. The amount of added resins is 2 to 25 wt .-% based on the finished mixture.

The use of obtained by various methods Coumarone indene resins, including the dark types, and from the pyrolysis residues of Production of olefins from petroleum resins. By the resin additive according to the invention is the Sedimentation rate of the solid particles reduced to the extent that no sediment deposits be observed during storage. This Stabilizing effect is on one physico-chemical interaction between the im End product suspended solid particles and the Resin component attributed.

It is known to use bitumen or tar with high polymer To mix acrylates or methacrylates in order to Adhesion and softening point increase and to lower the breaking point at the same time (DE-OS 23 31 727). However, these additions are not suitable to the pitch-bitumen mixtures mentioned stabilize.

DE-OS 30 37 279 proposes one Tar-bitumen mixture a thermoplastic polymer, such as for example a styrene-butadiene rubber or a Ethylene vinyl acetate copolymer. To this Way becomes a sprayable binder for the  Maintenance of road surfaces get the one improved adhesiveness, a higher Softening point and a lower breaking point having. These additions are also not for the Suitable for stabilizing pitch-bitumen mixtures.

In DE-OS 20 15 564 it is proposed that elastic asphalt mixes thereby the strength increase that bitumen blended with tar oils a mixture of bitumen and an aromatic Hydrocarbon resin is added. As aromatic Hydrocarbon resins are according to Ullmann's encyclopedia of technical chemistry, volume 12, 4th edition (1976), Pp. 539-542, polymerized vinyl aromatic Watch connections. Such resins are for those Stabilization of pitch-bitumen mixtures unsuitable.

According to the coal tar pitch with a Softening point (ring and ball) from 40 to 120 ° C (RuK) and a toluene insoluble content (TI) of up to 30% by weight, if necessary after plasticizing by adding high-boiling coal tar oils, with the aromatic hydrocarbon resins above the softening point of the pitch mixed homogeneously. After that, a petroleum bitumen is penetrated DIN 52 010 from 20 to 200.1 / 10 mm, preferably 40 to 120 x 1/10 mm, and the mixture above 120 ° C, preferably above 150 ° C, homogenized. In addition to the distilled bitumen common in road construction is mainly extract bitumen for production of the mixtures according to the invention.

The stability of the mixtures is based on the  "Tube test method" according to G. Zenke (Bitumen, 1973, No. 1, pp. 11-14) determined, supplemented by microscopic Observations.

The stabilized binder obtained according to the invention also points towards the binder according to the DE-PS 26 23 574 some additional advantages that justify the higher manufacturing costs. So points those with the binder stabilized according to the invention manufactured road surface layer improved  visco-elastic properties that increased Fatigue strength and greater adhesion to the Effect minerals.

The inventive method is based on the following examples explained in more detail.

Example 1

To 50 parts by weight of coal tar pitch with one Softening point (RuK) of 78 ° C, 26.7% by weight toluene-insoluble and 9.8% by weight quinoline-insoluble Ingredients are 20 parts by weight of high-boiling Anthracene oil (start of boiling: 258 ° C, 5 vol.% At 285 ° C, at 360 ° C: 34% by volume) and 35 parts by weight of light Coumarone indene resin with a softening point (RuK) of 75 ° C added and at 180 ° C for 30 min with stirring intimately mixed. Then 240 parts by weight Extract bitumen (DEX-80) with a softening point (RuK) of 52.4 ° C and a penetration of 88 · 1/10 mm added and the mixture again 30 min stirred under the same conditions. That so produced mixture has a softening point (RuK) of 48 ° C and a penetration of 102 · 1/10 mm and corresponds approximately to a bitumen B 80 Results of density measurements at Tube test procedures below 150 ° C are in Table 1 listed. Sample numbering is from below (1) upwards (5). The microscopic examination shows even after 14 days that the mixture remains homogeneous and does not separate.  

Example 2 (comparison)

As a comparison, a pitch-bitumen mixture is the same Way and with the same raw materials as in Example 1, but without the coumarone indene resin produced. The binder obtained in this way has one Softening point (RuK) of 44.5 ° C and penetration of 122 x 1/10 mm. It shows up under the microscope immediately an uneven distribution of the insoluble Particles in larger groups that already exist accumulated in the lower sample (1) after 4 days to have. The results of the tube test procedure are in reproduced in Table 1.

Example 3

To 50 parts by weight of coal tar pitch and 20 parts by weight of anthracene oil, with properties as in Example 1, 50 parts by weight of a Hydrocarbon resin from pyrolysis residues of Olefin production from gasoline with a softening point (RuK) of 105 ° C and 60 min at 170 ° C stirred. Then 280 parts by weight of bitumen (DEX-80) mixed in as in Example 1. The mixture is homogeneous and has a softening point (RuK) of 46 ° C and one Penetration of 102 x 1/10 mm. After 14 days of storage at 150 ° C is only shown in the lower sample (1) a very slight accumulation of insoluble ones Components. The density distribution after Tube test procedure is in Table 1 reproduced.  

Examples 4 to 7 (comparison)

Example 1 is repeated, but instead of Coumaron-Inden-Harzes other known from the literature Polymers added to the coal tar pitch at 150 ° C will. The finished mixtures are only microscopic examined. It shows that segregation of the system components takes place with lump formation. The results for the different polymers are reproduced in Table 2.

As the examples show, only indene type resins are used suitable to the pitch-bitumen mixtures mentioned stabilize. Bright coumarone indene resins show the greatest effectiveness. Become the cheap dark ones Hydrocarbon resins from pyrolysis oil used, so larger quantities are required to achieve the same To achieve effect.  

Table 1

Change in density in the tube test procedure

Table 2

Claims (7)

1. A method for stabilizing coal tar pitch-bitumen mixtures, characterized in that the coal tar pitch is mixed with aromatic hydrocarbon resins of the indene type or a technical product containing these resins before the bitumen is added. 2. The method according to claim 1, characterized in that that the resin the coal tar pitch at a Temperature above the softening point of the Pitch in an amount of 2 to 25 wt .-%, based to the finished mixture, is added and that finished, bituminous mixture above 120 ° C, is preferably homogenized above 150 ° C. 3. The method according to claims 1 and 2, characterized characterized in that as a hydrocarbon resin Coumarone indene resin is used.   4. The method according to claims 1 and 2, characterized characterized in that as a hydrocarbon resin from the residual oil of gasoline pyrolysis for Manufacture of olefin-derived resin used becomes. 5. The method according to claims 1 to 4, characterized characterized in that the bitumen component Extract bitumen with a penetration after DIN 52 010 is between 40 and 120 · 1/10 mm. 6. The method according to claims 1 to 5, characterized characterized in that the coal tar pitch a Softening point (ring and ball) between 40 and 120 ° C and up to 30 wt .-% toluene insoluble contains. 7. The method according to claims 1 to 6, characterized characterized that the Coal tar-bitumen mixture with tar oils is plasticized.