JP2003211469A - Vulcanized rubber chip molded product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low-priced vulcanized rubber chip molded product with high strength and reliable durability. <P>SOLUTION: The vulcanized rubber chip molded product is molded out of vulcanized rubber chips without using a resin binder. The vulcanized rubber chip molded product shows that a polymer component in an interface between the vulcanized rubber chips is the same as the vulcanized rubber chips. The crosslinking density of the surface of the vulcanized rubber chip is desirably lower than that of the interior of the vulcanized rubber chip by devulcanizing the surface of the vulcanized rubber chip using an oil process or the like. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a vulcanized rubber chip molded body obtained by molding a vulcanized rubber chip.

[0002]

2. Description of the Related Art Conventionally, as a vulcanized rubber chip molded body using vulcanized rubber chips, vulcanized rubber chips obtained from rubber products such as automobile waste tires and weather strips are bonded with a resin binder such as urethane or epoxy. What you have done is known. As described above, when the resin binder is used, the vulcanized rubber chips are not chemically bonded (primarily bonded) to each other, and a certain amount is required in order to form the molded body by the physical bond and the costume of the resin binder. Is. Usually, with respect to 100 parts by weight of the vulcanized rubber chip,
The resin binder needs to be about 10 to 50 parts by weight. Such vulcanized rubber chip moldings can be used for roads, sidewalks, parks,
It is used for paving materials in stadiums, car stops, diagonal guide poles, and objects in parks.

For example, a pavement material using this vulcanized rubber chip molded body has elasticity as compared with ordinary asphalt pavement and interlocking blocks because it uses vulcanized rubber chips which are elastic aggregates. By setting the porosity to several 10% during molding, water permeability and walking feeling are improved. Further, in the case of a sidewalk, the air gap suppresses the generation of air pumping noise generated from the tire due to such a gap and can absorb the sound of a specific frequency propagating from the traveling vehicle. Furthermore, this pavement material has the excellent characteristics that it can significantly reduce traffic noise by reducing tire impact noise and pattern vibration noise generated by the impact when the tire comes in contact with the road surface. There is.

[0004]

However, in the vulcanized rubber chip molded body molded by the above-mentioned manufacturing method, the adhesiveness between the resin binder and the vulcanized rubber chip is not good, and deterioration of the resin binder occurs over time, The vulcanized rubber chips are scattered, causing a problem of poor durability and a problem of yellowing depending on the resin binder. In addition, due to the viscosity of the resin binder, the mixture sticks to the stirrer after stirring the vulcanized rubber chips and the resin binder, which causes a problem that cleaning is difficult.

On the other hand, in order to improve the adhesion between the vulcanized rubber chip and the resin binder, there is a method of pretreating the surface of the vulcanized rubber chip with a pretreatment agent such as polyol. However, using this method,
Although the initial adhesiveness is improved, the deterioration of the resin binder is not suppressed for a long period of time, so that the vulcanized rubber chips eventually scatter and the durability is not improved. Further, since urethane resin, epoxy resin, or the like, which is a resin binder for adhesion, is expensive, there is a problem that the cost of the vulcanized rubber chip molded body using this is also expensive.

The present invention is intended to solve the above problems, and an object of the present invention is to provide a vulcanized rubber chip molded body having high strength, excellent durability, and low cost.

[0007]

Means for Solving the Problems and Effects of the Invention In order to achieve the above object, a structural feature of the invention according to claim 1 is that a vulcanized rubber chip molded body is formed by using a vulcanized rubber chip. That is, the vulcanized rubber chips are molded without using a resin binder.

The vulcanized rubber chip molded body is formed by compression-molding vulcanized rubber chips, but inorganic and organic hard aggregates are also mixed if necessary.
Rubber materials such as natural rubber and synthetic rubber are used for the vulcanized rubber chips. Examples include used tires, weather strips, belts, hoses, seismic isolation rubber, anti-vibration rubber, oil seals, etc. The burr rubber used at that time is used, but currently, vulcanized rubber chips produced from waste tires and weather strips, which are generated in large quantities from the viewpoint of resource reuse, are preferably used. The shape of the vulcanized rubber chip includes a hijiki type and a granular type. The method of manufacturing the vulcanized rubber chips is generally performed using a cutter, roll, crusher, freeze crusher, etc.
It is not limited to this.

In the invention according to claim 1 configured as described above, the vulcanized rubber chips are compression-molded so that the vulcanized rubber chips are bonded to each other at the contact portion without using the resin binder, It can be a molded body. In this way, since the vulcanized rubber chips are bonded to each other and the resin binder is not used, the vulcanized rubber chips are not scattered due to the deterioration of the resin binder, and the durability thereof is secured. Further, since the present invention directly bonds the vulcanized rubber chips to each other without using the resin binder at the bonding interface between the vulcanized rubber chips, there is a manufacturing constraint that causes a problem when the resin binder is used. Absent. That is, when a resin binder is used, the mixing of the materials used, and the reaction of the resin binder may proceed during the molding of the mixed material, and the molding time is limited. There are no such restrictions. Also, depending on the viscosity of the resin binder, after stirring the vulcanized rubber chip and the resin binder,
The mixture does not stick to the stirrer, and there is no trouble in maintaining the stirrer, which makes cleaning afterwards difficult.

Further, the constitutional feature of the invention according to claim 2 is that in the vulcanized rubber chip molded body according to claim 1, the polymer component of the bonding interface between the vulcanized rubber chips is a vulcanized rubber chip. To be the same.

In the invention according to claim 2 configured as described above, the vulcanized rubber chips are directly bonded to each other without using any other polymer component such as a resin binder at the bonding interface between the vulcanized rubber chips. Therefore, compatibility with the vulcanized rubber chip interface is good and bonding is easy, and it is possible to mold an inexpensive vulcanized rubber chip molded body having high strength and excellent durability.

As a method for bonding the vulcanized rubber chips to each other, the residue of the vulcanizing agent in the vulcanized rubber chips is used for compression molding as it is, or a vulcanizing agent, a vulcanization accelerator, a rubber paste or the like is newly added. It may be added and compression molded. For example, as the vulcanizing agent to be added, sulfur, zinc oxide, 4,4 '
-Dithiodimulforin, tetramethylthiuram disulfide, benzothiazole, dicumyl peroxide, p-
Examples include quinone dioxime and ammonium benzoate. Hexamethylenetetramine as a vulcanization accelerator,
n-butyraldehyde aniline, diphenylguanidine, ethylenethiourea, 2-mercaptobenzothiazole, N-cyclohexyl-2-benzothiazolyl-sulfenamide, tetramethylthiuram disulfide,
Examples include zinc dimethyldithiocarbamate and zinc butylxanthate. The vulcanizing agent and vulcanization accelerator are selected according to the rubber type.

Further, the constitutional feature of the invention according to claim 3 is that in the vulcanized rubber chip molded body according to claim 1 or 2, a vulcanized rubber chip having a surface cross-linking density smaller than that of the inside. It is that it is molded using.

In the invention according to claim 3 configured as described above, since the cross-linking density of the surface of the vulcanized rubber chip is lower than that of the inside, bonding at the rubber chip interface is facilitated, and the vulcanized rubber chip is easily bonded. It is possible to mold an inexpensive vulcanized rubber chip molded body having high strength and excellent durability as described in 1.

For example, as a method for reducing the crosslink density on the surface of the vulcanized rubber chip as compared with the inside, there are devulcanization and high temperature treatment. Devulcanization of the vulcanized rubber chip is to depolymerize long molecular chains of the vulcanized rubber chip by oxygen, heat and mechanical action (mechanical shearing action). Specifically, there are an oil method (bread method), an alkali method, a neutral method, a reclaim meter method and the like.

(1) The oil method is a method in which a vulcanized rubber chip is mixed with a regenerant and packed in a container, the container is placed in a regenerated desulfurization can, and steam is blown directly into the regenerated devulcanized at high temperature and high pressure. . (2) The alkali method is a method in which an aqueous sodium hydroxide solution is added to a vulcanized rubber chip, the mixture is placed in a double can equipped with a stirring blade, and steam is passed through the outer can to perform devulcanization. In the alkali method, after devulcanization, the vulcanized rubber chips must be sufficiently washed with water until the alkali is removed, and further dried, which causes a problem of increasing the number of steps. (3) The neutral method is basically the same as the alkaline method,
An aqueous solution of a metal chloride such as zinc chloride is used instead of sodium hydroxide. (4) The reclaim meter method is a method in which a vulcanized rubber chip is mixed with a regenerant and the mixture is passed through a special extruder called a reclaim meter for continuous devulcanization. Of the above four devulcanization methods, the oil method (bread method) is taken into consideration considering the conditions such as workability, maintaining the shape of the vulcanized rubber chip, and devulcanizing only the surface side of the vulcanized rubber chip.
Is the most desirable method.

The high temperature treatment of the vulcanized rubber chips means a method of cutting the cross-linking points of the vulcanized rubber chips by applying heat of 100 ° C. or higher, preferably 150 ° C. or higher in an oxygen-free column, or by rubbing the vulcanized rubber chips together. There is a method of cutting the heat generated by the heating at the cross-linking point.

As a method for bonding the vulcanized rubber chips having a surface cross-linking density smaller than that of the inside, the vulcanizing agent residue in the vulcanizing rubber chips is used for compression molding as it is, or a new vulcanizing agent is added. Alternatively, a vulcanization accelerator, a rubber paste or the like may be added to perform compression molding. For example, as the vulcanizing agent to be added, sulfur, zinc oxide, 4,4′-dithiodimulpholine, tetramethylthiuram disulfide, benzothiazole, dicumyl peroxide, p-quinone dioxime, ammonium benzoate and the like can be mentioned. As the vulcanization accelerator, hexamethylenetetramine, n-butyraldehyde aniline, diphenylguanidine, ethylenethiourea, 2-mercaptobenzothiazole, N-cyclohexyl-2-benzothiazolyl-sulfenamide, tetramethylthiuram disulfide, zinc dimethyldithiocarbamate. , Zinc butyl xanthate, etc. The vulcanizing agent and vulcanization accelerator are selected according to the rubber type.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing an elastic pavement structure in which a vulcanized rubber chip molded body according to one embodiment is laid on a promenade in a park, a roadbed or the like.

The pavement material 11 is a flat plate having a thickness of 20 to 50 mm, and is made of vulcanized rubber chips (hijiki type, granular type, etc.) whose surface cross-linking density is smaller than that of the inside. A method for reducing the cross-linking density on the surface of the vulcanized rubber chip as compared with the inside is performed by the oil method (pan method) using a vulcanizing can into which steam can be injected.
The vulcanized rubber chips and the regenerant are mixed and placed in a vulcanizer, for example, steam having a vapor pressure of 5 to 20 Kgf / cm ² is introduced for 3 to 8 hours for treatment. In addition, a hard aggregate is added to the above-mentioned molded body if necessary. Examples of hard aggregates include silica sand and gravel, which have an average particle size of 0.01.
It is desirable that the two conditions are satisfied: ~ 2.6 mm, and the compounding amount is 5 to 35% by weight based on the total compounding amount including the elastic aggregate.

The above-mentioned vulcanized rubber chip is provided with a porosity of 40, for example.
%, The mixture is put into a mold, and the mold is heat-treated at 150 ° C. for 60 minutes by a hot press to form a pavement material which is a vulcanized rubber chip molded body. However,
The molding conditions (molding method, temperature, time) are not limited to these.

As described above, the pavement material 11, which is a vulcanized rubber chip molded body, does not use a resin binder by compression-molding vulcanized rubber chips having a surface cross-linking density smaller than that of the inside. However, it is formed by bonding the vulcanized rubber chips to each other at the contact portions. In this way, by bonding the vulcanized rubber chips to each other, a strong bond is formed, and the pavement material 11 having high strength and good durability is obtained. Also, paving material 11
Since no resin binder is used, the vulcanized rubber chips do not peel off and scatter due to deterioration of the resin binder, and the durability thereof is secured.

Further, since the resin binder is not used, in the production of the pavement material 11, there is no possibility that the reaction of the materials will proceed between the mixing of the used materials and the molding of the mixed material, and therefore the manufacturing time is increased. There are no restrictions. Further, since no resin binder is used, there is an advantage in manufacturing that the mixture does not stick to the stirrer after the raw materials are stirred and the stirrer can be easily maintained. Further, since the pavement material 11 does not use an expensive resin binder, the cost is significantly reduced as compared with a pavement material using a conventional resin binder.

As shown in FIG. 1, this pavement material 11 is a roadbed 1 such as concrete or asphalt provided on the ground 14.
3 is laid by adhering it to the adhesive layer 3 using an epoxy-based or urethane-based adhesive 12 to form a drainage elastic pavement structure.

In addition to the effects obtained by the vulcanized rubber chip molded body and the manufacturing method thereof, the pavement material 11 is more elastic than ordinary asphalt pavement due to the use of vulcanized rubber chips, and By setting the porosity of several tens of percent at the time of molding, water permeability is obtained, and the generation of air pumping noise generated from the tire is suppressed by such voids, and the sound of a specific frequency propagating from the traveling vehicle is absorbed. it can. Further, the pavement material 11 has excellent characteristics such that the traffic noise can be significantly reduced by reducing the tire impact sound and the pattern vibration sound generated by the impact at the time of contact between the tire and the road surface. There is.

When a hard aggregate such as sand satisfying the above two conditions is added to the pavement material 11, the sliding friction coefficient can be further increased when the surface of the pavement material is wet. it can. Therefore, while ensuring noise absorption and drainage of the pavement material, braking the vehicle on a wet road surface such as during rain can be made closer to braking the vehicle on a dry road surface, and the slip prevention effect is enhanced. As a result, it is possible to ensure operational stability even during rainfall.

Next, concrete examples of the pavement material according to the above embodiment will be described. In all of the examples of the pavement material, no resin binder was used, and only the vulcanized rubber chips were compression-molded in Example 1. The one in which sulfur and benzothiazole were added as the vulcanizing agent / vulcanization accelerator was used. In Example 2, a vulcanized rubber chip having a surface cross-linking density lower than that of the inside by the oil method (pan method) is used. The rubber paste shown in Table 3 below, which is a polymer component similar to that of Example 4, the vulcanized rubber chip, in which the reduced vulcanized rubber chip is used and sulfur and benzothiazole are added as a vulcanizing agent / vulcanization accelerator. Example 5 was the one in which sulfur and benzothiazole were added as the vulcanizing agent / vulcanization accelerator. Further, for each of Examples 1 to 4, Comparative Examples 1 to 4 using a resin binder were prepared. Table 1 below shows the combinations of the requirements for these examples, and Table 2 below shows the combinations of the requirements for the comparative examples.

The test items are the breaking condition of the pavement material in the tensile test and the workability of molding. The tensile test was performed according to JIS K6251. The rupture condition is judged by the rupture of the vulcanized rubber chip itself or the rupture at the boundary between the vulcanized rubber chips and the bonding surface.
The molding workability was rated as ∘ when the material did not stick to the stirrer when mixing the materials, and marked as x when the material stuck.

[0029]

[Table 1]

[0030]

[Table 2]

[0031]

[Table 3]

As shown in Table 1 above, in all of Examples 1 to 4, the vulcanized rubber chips themselves had a high fracture rate, and the adhesive strength and the adhesive reliability were high. Further, there is no sticking of the material to the stirrer at the time of mixing the materials, and the workability of molding is good.

On the other hand, in Comparative Examples 1 to 4,
As shown in Table 2 above, all the fractures have a high rate of fracture at the adhesive interface. Further, since the resin binder is used, the workability is poor because the material adheres to the stirrer when the materials are mixed.

The use of the above-mentioned pavement material is not limited to that for roads, but it can also be used for promenades, stadium fields, and the like. Further, the vulcanized rubber chip molded body of the present invention can be used not only as a paving material but also as a cushioning material, a sound absorbing material and the like.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an elastic pavement structure in which a pavement material (vulcanized rubber chip molded body) according to an embodiment of the present invention is laid on an automobile road.

[Explanation of symbols]

11 ... Pavement material, 12 ... Adhesive agent, 13 ... Roadbed, 14 ... Ground.

Continued front page    F term (reference) 2D051 AA02 AD07 AG03 AH02 DA11                       DC09                 4F204 AA50 AC01 AH43 FA01 FB01                       FG01

Claims (3)

[Claims] 1. A vulcanized rubber chip molded body formed by using vulcanized rubber chips, characterized in that the vulcanized rubber chips are molded without using a resin binder. Molded body. 2. The vulcanized rubber chip molded article according to claim 1, wherein the polymer component of the bonding interface between the vulcanized rubber chips is the same as that of the vulcanized rubber chip. 3. The vulcanized rubber chip molding according to claim 1 or 2, wherein the vulcanized rubber chip is molded using the vulcanized rubber chip having a cross-linking density on the surface smaller than that of the inside. body.