JPH09208832A - Improved asphalt and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low-cost improved asphalt by using a low-cost additive and to provide an efficient process for continuously producing the improved asphalt. SOLUTION: A waste synthetic rubber crushed to fine chips is supplied to a screw-type kneader extruder 1 and melt kneaded; a heated straight asphalt in a flowable state is supplied to the extruder 1; and the rubber in a molten state and the asphalt in a flowable state are mixed and extruded.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a modified asphalt and a method for producing the same.

[0002]

2. Description of the Related Art Generally, straight asphalt obtained by removing light components from crude oil is widely used as petroleum asphalt for paving roads and the like. However, depending on the application or the region where it is used, the purpose of use is not sufficiently achieved with only straight asphalt, and a reinforcing substance is appropriately added to the straight asphalt to be used as a modified asphalt. Especially for cold and snowy regions, styrene-butadiene rubber (SBR), styrene-isoprene-styrene (SI
S), styrene / butadiene / styrene (SBS), vinyl acetate copolymer (EVA), ethylene / ethyl acrylate copolymer (EEA), or other synthetic rubber (thermoplastic elastomer) alone or in combination. Has been added.

Conventionally, such modified asphalt is manufactured as follows. That is, a synthetic rubber is a granulated product in a petrochemical factory, in which a rubber raw material synthesized by a synthesizer is devolatilized and removed by a screw type vent extruder to remove volatile substances such as a solvent, and physical properties are stabilized. It is made into pellets. The synthetic rubber pellets thus obtained are heated together with straight asphalt in a heating pot and melt-mixed to produce a modified asphalt.

[0004]

Since the conventional modified asphalt is produced as described above, the following problems exist. That is, the reinforcing substances added for reforming are virgin materials produced in petrochemical plants, and are more effective and more valuable and valuable.
Further, the modified asphalt is manufactured in a batch-type heating pot and is discontinuously produced.

The present invention has been made to solve the above problems, and is an inexpensive modified asphalt using an inexpensive additive material, and an efficient production for continuously producing the modified asphalt. The purpose is to provide a method.

[0006]

The modified asphalt according to the present invention is straight asphalt in which waste synthetic rubber is melt-mixed.

According to the method for producing modified asphalt according to the present invention, waste synthetic rubber crushed into small pieces is supplied to a screw type kneading extruder in a fixed amount, kneaded and melted, and straight asphalt in a heated and fluidized state is kneaded with the screw type kneader. It is a method in which a fixed amount is supplied to an extruder, and the waste synthetic rubber in a molten state and the straight asphalt in a fluid state are mixed and extruded.

More specifically, the waste synthetic rubber crushed into small pieces is kneaded and melted by rotating the screw of the screw type kneading extruder at a low speed.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the modified asphalt and the method for producing the same according to the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram showing a modified asphalt manufacturing apparatus according to the present invention.

In the figure, reference numeral 1 is a screw-type kneading / extruding machine. A cylinder 1A constituting the screw-type kneading / extruding machine 1 has a hopper port 1a at its base and a vent port 1b at its middle part. An additive material supply port 1c is provided on the tip end side, and an extrusion nozzle 1d is provided on the tip end portion, which communicates with the inner hole of the cylinder. Further, the cylinder 1A is provided with a cooling device and a heating device (not shown). Further, a drive unit 3 for rotationally driving the screw inserted in the cylinder 1A is connected to the base of the screw type kneading extruder 1 via a drive speed reducer 2. The hopper mouth 1a
The raw material supply device 4 for quantitatively supplying the crushed material
Is connected. A suction pump 5, which is a vacuum pump for sucking and exhausting gas components, is connected to the vent port 1b, and a separator 6 is further connected. A heating tank 8 is connected to the additive material supply port 1c via a solution pressure pump 7 for quantitatively pressure-feeding the viscous fluid substance.

A case in which the modified asphalt is actually manufactured by the modified asphalt manufacturing apparatus configured as described above will be described below. First, in the screw-type kneading extruder 1, a heating device (not shown) and a cooling device (not shown) are operated to heat the cylinder so that the temperature of the cylinder and the temperature distribution in the axial direction are adjusted to a predetermined operating condition. . In the raw material supply device 4, waste synthetic rubber (crushed material) that has been crushed by another crushing device in advance is stored in the storage section. The suction pump 5 is operated so that a predetermined suction pressure can be obtained. In the heating tank 8, the straight asphalt is heated to a predetermined temperature, kept in a fluid state, and stored. Next, the operation of the raw material supply device 4 is started, and the stored crushed material is fed into the screw type kneading extruder 1
It is quantitatively supplied to the hopper mouth 1a. The driving of the driving machine 3 is started almost at the same time as the crushed material is supplied to the hopper port 1a, and the screw type kneading extruder 1 is driven through the driving speed reducer 2.
The screw is driven to rotate at a predetermined rotation speed. Hopper mouth 1
The crushed material supplied from a to the cylinder is heated by the kneading operation, that is, the heating from the cylinder wall surface and the shearing operation between the cylinder and the rotating screw, and is gradually melted (kneading and melting) while the screw is transported. Moves toward the tip by. The gas component generated when the crushed material is melted is forcibly sucked and discharged from the vent port 1b by the suction pump 5, and the harmful component, the odor component and the useful component are separated and removed by the separator 6, and then released into the atmosphere. Next, the operation of the solution pressure pump 7 is started, and the straight asphalt stored in the heating tank 8 is quantitatively pressure-fed to the additive material supply port 1c of the screw type kneading extruder 1. The straight asphalt supplied from the additive material supply port 1c into the cylinder has its gas component removed and mixed with the molten waste synthetic rubber by the kneading action of the rotating screw. Waste synthetic rubber is the additive material supply port 1
By the time it reaches the position c, it is in a completely melted state and is easily mixed with the straight asphalt in a fluid state supplied from the additive material supply port 1c. The mixture of the waste synthetic rubber and the straight asphalt is mixed and gradually cooled by the cylinder cooled by the cooling device, moved toward the tip end by the transporting action of the screw, and uniformly mixed with a predetermined component ratio. The asphalt is extruded from the extruding nozzle 1d at the tip. The modified asphalt extruded from the extrusion nozzle 1d is stored in a container (not shown).

In the above-mentioned modified asphalt manufacturing process, in order to prevent the decrease of the molecular weight of the waste synthetic rubber due to the shearing action as much as possible, the rotation speed of the screw is low, and the waste synthetic rubber has a long residence time in the cylinder. Then, it is melted mainly by heating from the cylinder. When the waste synthetic rubber in a molten state is mixed with the straight asphalt, the waste synthetic rubber is mixed with cooling by a cylinder in order to prevent gasification of the waste synthetic rubber. Waste tires are mainly used as waste synthetic rubber, which is the additive material of modified asphalt, but wastes of various synthetic rubbers listed in the above-mentioned conventional technology and waste materials (half-sized wastes) generated during processing are used. To be done.
The total amount of the additive material is not limited to the waste synthetic rubber, and the waste synthetic rubber and the unused synthetic rubber material may be mixed and added at a predetermined ratio. As the screw-type kneading extruder 1 which is the main equipment of the manufacturing apparatus, a co-rotating twin-screw kneading extruder is desirable, but a hetero-rotating twin-screw kneading extruder or a single-screw kneading extruder can also be used. Can be implemented.

[0013]

EXAMPLES Examples of producing modified asphalt will be described below. Modified asphalt satisfying the standard value was obtained by the following equipment and materials. From this production example, it was found that a lower screw rotation speed is desirable. (1) Screw type kneading extruder TEX44α-42AW-1V (Japan Steel Works Co-rotating twin-screw kneading extruder) Screw diameter (D): 47 mm Screw length (L / D): 42 (L: long) Cylinder heating device: Electric heating with cast aluminum heater Cylinder cooling device: Water cooling by cylinder water passage Exhaust system: One-stage vent (2) Material Crushed waste tires for passenger cars: 2-3 mm irregular shape Crushed product Straight asphalt 60 to 80: Supplied in a heated and melted state at 150 ° C (3) Production results Table 1 shows.

[0014]

[Table 1]

[0015]

The modified asphalt and the method for producing the same according to the present invention are configured as described above, so that the following effects can be obtained. (1) Since the reinforcing material added for reforming is waste synthetic rubber, it is very inexpensive and in some cases it is collected for a fee.Use such waste synthetic rubber. Thus, inexpensive modified asphalt is manufactured. (2) By reusing used waste synthetic rubber instead of unused synthetic rubber, effective use and saving of resources can be achieved. (3) Waste synthetic rubber, such as waste tires, is an industrial waste that is difficult to dispose of and is therefore expensive to dispose of, but such waste synthetic rubber is effectively used only by crushing. This can contribute to solving environmental problems caused by industrial waste. (4) Waste synthetic rubber and straight asphalt are supplied to a screw-type kneading extruder and melt-mixed to produce a modified asphalt, whereby the modified asphalt is continuously and efficiently produced. (5) By quantitatively supplying waste synthetic rubber and straight asphalt, a screw type kneading extruder capable of steady continuous operation can continuously produce a modified asphalt of a certain quality. (6) Rotate the screw of the screw type kneading extruder at low speed,
By preventing a decrease in the molecular weight of waste synthetic rubber during kneading and melting, a modified asphalt satisfying the required properties can be produced. That is, it becomes possible to reuse the waste synthetic rubber as a reinforcing material similar to the unused synthetic rubber.

[Brief description of drawings]

FIG. 1 is a block diagram of an apparatus for producing modified asphalt according to the present invention.

[Explanation of symbols]

 1 screw type kneading extruder 1a hopper port 1b vent port 1c additive material supply port 1d extrusion nozzle 4 raw material supply device 5 suction pump 7 solution pressure pump 8 heating tank

Claims (3)

[Claims] 1. A modified asphalt in which waste synthetic rubber is melt-mixed with straight asphalt. 2. A screw type kneading extruder (1), which supplies a fixed amount of waste synthetic rubber crushed into small pieces, is kneaded and melted, and heated straight asphalt is flowed to the screw type kneading extruder (1). A method for producing a modified asphalt, characterized in that the waste synthetic rubber in a molten state and the straight asphalt in a fluidized state are mixed and extruded after being supplied in a fixed amount. 3. The waste synthetic rubber crushed into small pieces,
The method for producing modified asphalt according to claim 2, wherein the screw of the screw type kneading extruder (1) is rotated at a low speed to be kneaded and melted.