Note: Descriptions are shown in the official language in which they were submitted.
105Z057
This invention is concerned with asphalt compositions, particularly
for use in asphalt road surfaces.
In principle theory, in road asphalt production technology no modi-
fying additions are needed, due to the thick dressing of asphalt used and the
costs connected with modifying it. In fact, methods of improving road surfaces
by adding to the asphalt non-vulcanized natural and synthetic rubbers in a
quantity of up to 5% by weight, are known and widely used. The addition of
reclaimed rubber [obtained by heating rubber scraps to a temperature of 180
under a pressure of 5 atm in the presence of peptizing agents and plasticizers]
has also been used. These additions improved both the durability of the
asphalt surface, and its adhesion or stability; i.e., deformation resistance
at great load, freeze resistance, grindability, adhesion to the aggregates
etc. mese properties have been exhibited in a somewhat smaller degree by
asphalt having a rubber dust addition.
Known asphalts modified with the aid of additions of rubber origin
are expensive due to the high costs of the employed raw materials. In case of
rubbers, and reclaimed rubber, the procedure of reducing the vulcanized rubber
scraps to the required size of about 0,1 mm is troublesome and expensive.
This invention seeks to provide an improved asphalt containing
rubber materials. Thus in a broad aspect this invention provides an asphalt
composition suitable for road surfaces comprising an asphaltic basis material
and a modifier, the modifier comprising from 1-50% by weight of rubber thermal
degradation products in a medium chosen from petroleum asphalts, mineral oil
selective refining residues, kerosene heavy residues, or coal tar oil residues,
; the degradation of the rubber being effected by heating it at a temperature of
from 240-380 C in the chosen medium.
The modifying component used in the asphalt of this invention is
obtained by heating rubber scraps, such as spent tires, inner tubes, and in-
dustrial waste, in petroleum asphalt, the extract remaining after refining of
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oils with the aid of selective solvents, or heavy products of coal tar dis-
tillation at a temperature of 240-380 C.
According to a preferred embodiment of the invention, rubber scraps
in a quantity of 1-50% by weight, are introduced into distillation asphalt,
oxidized asphalt propane refined asphalt, and or natural asphalt one, and
heated at a temperature of 220-360 C to cause liquefaction of the mixture.
In order to elevate the softening point and lower the penetration, the obtained
asphalt containing the rubber scrap can be oxidized with the aid of air at a
temperature of 200-320&, or subjected to distillation either at a lowered `
pressure or with steam.
The rubber scraps can be subjected to destruction by introducing
` them into the asphalt during the oxidation, or during the distillation process.
According to another method the modifying component is obtained by
heating the rubber scraps at a temperature of 240-380 C in the presence of
petroleum asphalt, extracts remaining after selective refining of mineral oils,
heavy products from destructive processing of kerosene products, or heavy coal
; tar products, the heated mixture containing from 1 to 80% by weight of rubber
scraps. The mixture obtained is introduced into petroleum asphalt, or natural
asphalt, in such a quantity that the content of processed rubber scraps in the
finished asphalt preferably amountsto 1-50% by weight.
The modified asphalt can be subjected to an oxidation process by
means of air at a temperature of 220-320 C, or to distillation at decreased
pressure, or to distillation with steam, in order to obtain the desired prop-
erties. It is also possible to separate the low-boiling components from the
modifying component by subjecting it to distillation at reduced pressure, or
to steam distillation. The distillation of rubber scrap containing products
makes it possible to remove the low-boiling disagreeable-smelling components
of the rubber scrap and to obtain a finished asphalt exhibiting a higher ignition
temperature and a higher thermal stability.
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l~S~057
The road asphalt obtained according to the invention methods
has good performance characteristics, especially thermoplastic ones. Asphalt
surfaces obtained by the use of asphalts modified with rubber scrap also have
good adhesion to tires and high loading resistance.
Example I
53 kg of asphalt residue containing 3,2% by weight of paraffin are
oxidized by means of air to a penetration at a temperature of 25 C equal to
36. 50 kg of the obtained oxidized asphalt are mixed at a temperature of
380 C with 50 kg of granulated spent tires over 40 minutes, with simultaneous
10 blowing with superheated steam. The obtained mixture is distilled at a
pressure of lS mm of mercury and asphalt exhibiting the following properties
is obtained:
- softening point according to the ring and ball method .... 61 C
-penetration at 25 C, the loading being 100 g for 5 sec .. 24mm/10
-brittle point.............................................. -7 C
-ductility at 15C.......................................... 8 cm
Example II
90 kg of distillation asphalt showing a penetration of 101 mm/10 at
a temperature of 25C,is heated to a temperature of 280C, and 10 kg of
granulated spent tires introduced. The mixture is mixed at this temperature
for 1.5 hours. The mixture obtained is oxidized with the aid of air at a
temperature of 200 C for 28 hours. The asphalt shows the following properties:
-softening point according to the ring and ball method ..... 65&
-penetration at 25C, the loading being 100 g for 5 sec.... 33 mm/10
-brittle temperature ....................................... -9C
Example III
30 kg of furfural extract, showing a viscosity of 2.6 E at a tempera-
ture of 100 C, is heated to a temperature of 340 C, and 70 kg of comminuted
tires are slowly added with simultaneous mixing, blowing with steam, and heat-
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1052057
ing in order to maintain the temperature of 360 C.
91 kg of rubber scrap solution and 9 kg of oil having a boiling point
of 220-380 C are obtained.
20 kg of rubber scrap solution are mixed with 80 kg of road asphalt
showing a penetration of 16 mm/10 at a temperature of 25C and then homogen-
ized on a toothed mill. The product exhibits the following properties:
-softening point according to the ring and ball method . . . . . . . . . 63 C
-penetration at 25&, the loading being 100 g for 5 sec. . . . . . . .59mm/10
-brittle temperature ................................ -16C
-ductility at 15 C . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 cm
Example IV
50 kg of anthracene oil and 50 kg of prevulcanized rubber scraps
were mixed together and the mixture was heated for 15 hours at a temperature
of 220C.
80 kg of natural asphalt showing a softening point of 118 C and a
penetration of equal to 0 mm/10 at a temperature of 25 C were mixed together ;
with 20 kg of a rubber scrap mixture and anthracene oil to provide an asphalt
exhibiting a softening point of 77 C and a penetration of 15 ~m/10 at a temp-
erature of 25&.
Example V
90 kg of asphalt residue are oxidized with air at a t~mperature of
260 -320&. During the oxidation process 10 kg of ground rubber scraps are
added in portions.
A homogeneous asphalt exhibiting a softening point according to the
ring-ball method of 53 C and a penetration of 48 mm/10 at a temperature of
25&, and a brittle temperature of -16 C is obtained.
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