JP2004188742A - Producing method for elastic material using waste tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To promote the recycling of a waste tire by providing a method for producing a good elastic material having a beautiful surface and a high market value using the waste tire. <P>SOLUTION: The almost ellipsoidal pressure chamber 27, which is expanded in its diameter so as to have a smooth curved surface, of a material extrusion passage 26 is formed in the mold 25 provided on an extrusion molding machine 2 while a molding flow channel 28, which has the same cross-sectional shape as the required cross section of a molded article and has a forced cooling means on its periphery, is provided on the downstream part of the pressure chamber. A kneaded mixture of the particulates of the waste tire and an elastic polymer is charged into the extrusion molding machine to be extruded by way of the pressure chamber and the molding channel. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for manufacturing an elastic material by recycling a waste tire.
[0002]
[Prior art]
[Patent Document 1]
JP 10-202658 A [Patent Document 2]
JP-A-10-151629 [Patent Document 3]
JP-A-10-151332
A method of recycling a waste tire in which the waste tire is pulverized, kneaded with a polymer, and molded into a desired shape is known from Patent Document 1 and the like.
[0004]
Patent Documents 2 and 3 disclose a method of recycling plastic waste materials according to the patent application of the present inventor, and sort plastic waste materials mixed with various synthetic resins such as thermoplastic or thermosetting. It is put into a mixing device equipped with high-speed rotating blades without stirring, stirred, melted by the frictional heat generated by the stirring, turned into a gel state, and charged into a molding machine as it is to mold a molded product It is.
[0005]
[Problems to be solved by the invention]
By the way, waste tires generated in large quantities are often in a state of being piled up without being able to catch up with the recycling process as described in the above-mentioned Patent Document 1, and thus have become a serious social problem as is well known. That is, according to the conventional waste tire recycling method, only a molded article having a rough surface and a low market value could be manufactured, so that the profitability was not met, and the reuse of the waste tire still did not proceed. According to the conventional molding method, when the polymer obtained by kneading the waste tire powder is pressed by an extruder and extruded from a die, the surface of the molded product becomes rough because the waste tire powder with poor slip is easily separated from the polymer. This was due to inferior product value.
[0006]
[Means for Solving the Problems]
SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and provides a method for easily producing a high-quality valuable elastic material having a smooth surface to facilitate recycling of waste tires.
For this purpose, the method for producing an elastic material by reusing a waste tire according to the present invention forms a substantially elliptical pressure chamber in which the inner diameter of a material extrusion passage is expanded with a smooth curved surface in a mold provided in an extruder. In addition, a molding passage having a required cross-sectional shape of the molded article and provided with forced cooling means around the molding chamber is provided downstream of the pressure chamber, and the kneading material of the waste rubber particles and the elastic polymer is extruded by the extrusion molding machine. And the kneaded material is extruded through the pressure chamber and the molding flow path.
In addition, the method for producing an elastic material by recycling waste tire according to the present invention is a method in which powder and elastic polymer of waste tire are charged into a mixing device having blades rotating at high speed, and frictional heat generated due to stirring of the mixing device. It is characterized in that it is melted into a gel state, which is put into a pressure molding machine and molded into a required shape.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, an embodiment of the present invention will be described with reference to the drawings. The waste tire is pulverized by a cutting machine, a pulverizer, or a freezing pulverizer to obtain powdery rubber particles (chip or powder) having a diameter of 1 mm to 5 mm. On the other hand, an elastic polymer (preferably a rubber resin such as RB (polybutadiene-based thermoplastic elastomer), SBR (styrene-butadiene rubber), or TPE (thermoplastic elastomer)) is used in a weight ratio of 80% of the waste rubber to the elastic polymer. Mix at a rate of 20%. Then, the mixed material is put into the hopper 21 of the extruder 2 shown in FIG.
[0008]
The extruder 2 is provided with a hopper 21 on the base upper surface of a horizontally supported cylinder 20, a screw 24 rotated by a motor 23 in the cylinder 20, and a die 25 at the tip of the cylinder. Is provided. Reference numeral 30 denotes a heater provided outside the cylinder.
[0009]
As shown in FIGS. 2 and 3, a material extrusion passage 26 is formed in the mold 25, and the inner diameter of the material extrusion passage 26 is expanded with a smooth curved surface, as shown in FIG. The pressure chamber 27 is formed in a substantially elliptical shape. Further, as shown in FIG. 5, a downstream side of the pressure chamber forms a forming channel 28 having a drum-shaped cross section so as to be connected to the pressure chamber 27 with a smooth curve. As shown in FIG. 6, the cross section of the drum is shaped into a rectangular shape as shown in FIG. A cooling water passage 29 is provided as forced cooling means by circulating cooling water around the molding flow passage 28.
[0010]
Reference numeral 31 denotes a roller for supporting the molded product extruded from the mold 25, and reference numeral 32 denotes a cool air blowing device provided further downstream thereof.
[0011]
Among the above elastic polymers, RB (polybutadiene-based thermoplastic elastomer) can be obtained by using a composition commercially available from JSR Corporation under the trade name (JSR RB 820): syndiotactic tic 1,2-polybutadiene. Best results can be obtained.
[0012]
The kneaded material of the waste tire powder and the elastic polymer put into the hopper 21 is pushed while being further mixed and stirred by rotating the screw 24, and the kneaded material is heated by the heater 30. Will be maintained. Then, the kneaded material is further pushed by the rotation of the screw 24 at a head pressure of about 300 kg / cm ² and reaches the pressure chamber 27 in the mold 25. Then, the kneaded material swirls in the pressure chamber 27 as indicated by the arrow and once flows backward. Thereby, the kneaded state of the waste rubber and the elastic polymer is maintained. In other words, the kneaded material may be separated from the waste rubber and the elastic polymer by friction with the inner wall surface of the extrusion passage and only the polymer having low flow resistance may be extruded first, but the pressure chamber formed in an elliptical shape may be used. The waste rubber and the polymer are remixed by swirling in 27, and immediately thereafter, they are forcedly cooled at the same time as they are molded through the molding flow path 28 and formed into a required cross-sectional shape. You. For this reason, the surface of the molded product extruded from the mold may be denser than ever before as a recycled product. It should be noted that the reason why the forming flow path 28 is once made to have a drum-shaped cross section as shown in FIG. 5 is to make the cooling speed up to the center of the thick molded product faster. The temperature of each part of the mold is appropriately set according to the mixing ratio of waste rubber and the type of polymer.
[0013]
The elastic material produced in this way has the characteristics of rubber and has a smooth surface skin so as not to be considered a regenerated product, so that it can be used widely and has high economic value. For this reason, it becomes possible to use the same as cushioning material and other general rubber products.
[0014]
In addition, in the present invention, by providing the pressure chamber 27, the extrusion speed, which was conventionally 700 to 1000 mm / min, that is, the molding speed can be significantly increased to 3000 mm / min. Efficiency can be improved.
[0015]
Next, an embodiment of the present invention will be described with reference to FIGS. In the mixing device 1 shown in FIG. 7, a helical screw 5 and a plurality of blades 6 are provided on a rotating shaft 4 that penetrates the inside of the chamber 3 so that the screw 5 and the blades 6 can be rotated at high speed by a motor 7. In the structure, reference numeral 8 denotes a material input hopper, 9 denotes an outlet, and 10 denotes a shutter provided at the outlet. In this embodiment, a material obtained by mixing 80% of the waste rubber with 20% of the elastic polymer is put into the hopper 8 of the mixing apparatus 1. Then, the waste rubber is melted by self-heating due to the impact friction with the blades 6 in the chamber 3, becomes a gel state kneaded with the elastic polymer, and the kneaded material is extracted from the discharge port 9 by opening the shutter 10.
[0016]
FIG. 8 shows an example of a pressure molding machine 42 including a lower mold 40 and an upper mold 41 for molding the kneaded material into a desired shape such as a plate or a box. The kneading material 50 in the gel state as described above is loaded into the lower mold 40 and the upper mold 41 is pressed down by the press molding machine 42 to form the kneading material into an elastic material having a desired shape. it can. The kneading material 50 is a material in which the waste rubber and the polymer are melted by the self-heating due to the impact friction with the blades 6 in the mixing device 1 to be in a gel state. Materials can be manufactured.
[0017]
【The invention's effect】
As described above, according to the present invention, waste tires can be reused, and a high-quality, particularly clean surface skin and high market value elastic material can be produced. is there.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of an extruder showing an embodiment of the present invention.
FIG. 2 is a longitudinal sectional view of a mold part of the extrusion molding machine of FIG.
FIG. 3 is a horizontal sectional view of FIG. 2;
FIG. 4 is a sectional view taken along line AA of FIG. 2;
FIG. 5 is a sectional view taken along line BB of FIG. 2;
FIG. 6 is a sectional view taken along line CC of FIG. 2;
FIG. 7 is a longitudinal sectional view of a mixing device showing another embodiment of the present invention.
FIG. 8 is a longitudinal sectional view of a pressure molding machine showing another embodiment of the present invention.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 mixing device 2 extruder 6 blade 7 motor 9 discharge port 25 mold 26 material extrusion passage 27 pressure chamber 28 molding passage 29 cooling water passage 42 pressure molding machine

Claims (2)

A substantially elliptical pressure chamber in which the inner diameter of the material extrusion passage is expanded with a smooth curved surface is formed in a mold provided in the extrusion molding machine, and a required cross-sectional shape of a molded product is provided downstream of the pressure chamber. Providing a molding channel provided with forced cooling means around the periphery, charging a kneaded material of waste tire powder and an elastic polymer into the extruder, and extruding the kneaded material through the pressure chamber and the molding channel. The manufacturing method of the elastic material which reused the waste tire characterized by the above-mentioned. The powder particles of the waste tire and the elastic polymer are put into a mixing device equipped with blades that rotate at high speed, melted by the frictional heat generated by the agitation, and turned into a gel state. A method for producing an elastic material by recycling waste tires, characterized by being molded into a shape.

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