JPS6323816B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing granular organic rubber chemicals, and more specifically, the present invention relates to a method for producing granular organic rubber chemicals, and more specifically, the method involves stirring and granulating organic rubber chemicals that have been heated and melted in water containing a specific granulation aid. This invention relates to a new method for producing granular organic rubber chemicals that have good fluidity and do not scatter dust. Organic rubber chemicals that are solid at room temperature, such as 2-
(morpholinothio)-benzothiazole (hereinafter referred to as
MTBT (abbreviated as MTBT) is commercially available as a rubber vulcanization accelerator, usually in the form of flakes or pellets, and is used in large quantities. However, in these forms, part of the shape may be lost or collapsed during handling such as transportation and weighing, resulting in insufficient fluidity due to the generated fragments and powder, which can be a problem when continuously using a fixed amount. This not only causes problems, but also causes the generated powder to scatter, which is unfavorable from the standpoint of environmental hygiene. An object of the present invention is to provide a method for producing granules that improves the drawbacks of the shape of conventional organic rubber chemicals and does not impair the dispersibility in rubber and the performance as rubber chemicals in practice. be. A known method for granulating a heated melt of MTBT in water is to use a solvent (see Japanese Patent Publication No. 15264/1983), but if a solvent is used, the process of recovering it and the waste water This method requires a solvent treatment step, which not only complicates the process, but also partially evaporates the solvent, which is unfavorable in terms of the working environment. In addition, when granulating the heated molten material by simply stirring it in water, the shape cannot be made uniform as described in the comparative example below, and furthermore, it may not adhere to the walls of the granulation tank. happened,
This is not preferable because it causes trouble in the process. Furthermore, a method has been proposed in which organic rubber chemicals are granulated in the form of solid powder by heating and stirring in water (see Japanese Patent Laid-Open No. 1983-62245, etc.), but this method requires that the entire amount of granulation raw material be pulverized into a fine powder. There are some difficulties, such as not being able to do so. As a result of intensive research to improve the drawbacks of conventional methods for granulating organic rubber chemicals, the inventors of the present invention have found that they do not scatter dust during handling, have good fluidity, and have good dispersibility in rubber. This has led to the creation of granules that do not impair their performance as rubber chemicals. That is, in producing granules of organic rubber chemicals that are solid at room temperature, the present invention uses a heated melt of the organic rubber chemicals and a powder of the same organic rubber chemicals as the melt as a granulation aid. The present invention provides a new method for producing granular organic rubber chemicals, which is characterized by stirring and granulating in water added as a granular organic rubber drug. Below, organic rubber chemicals are represented by MTBT.
The present invention will be explained. The granulation aid of the present invention (hereinafter abbreviated as core) is
Pulverized solid MTBT is used.
The particle size of the nucleus may be 0.5 mm or less, preferably about 0.1 to 0.3 mm. There is no particular need to make it into a fine powder. The amount of nuclei supplied varies depending on the size of the target particle.
The amount is preferably 0.5 to 30 parts by weight, preferably 5 to 20 parts by weight, per 100 parts by weight of the heated melt. Granules of any size can be obtained depending on the amount of the cores supplied, the temperature of the water in the granulation tank, and stirring conditions. Since MTBT powder is used as the core, other impurities will not be mixed in. MTBT usually has a melting point of 80° C. or higher, but in the present invention, MTBT is heated and melted to about 85° C. or higher and then added to the water in the granulation tank. Alternatively, MTBT can be prepared by heating and melting MTBT to about 85℃ or higher and adding it to water prepared separately in advance.
(temperature maintained at 80-85°C) and this dispersion may be added to the water in the granulation tank. The granulation temperature of the water in the granulation tank is preferably 70°C or lower, preferably 40 to 65°C. When the temperature exceeds 70°C, the added or formed nuclei become semi-molten and cannot be granulated instantly even when MTBT melt is added. Also 40℃
If granulation is carried out below, the particle size will become irregular, which is not preferable. The method of the present invention can be either a batch method or a continuous method, but especially in the case of a continuous method, a certain amount of nuclei is supplied into the granulation tank, and after that, the nuclei are not supplied, but the nuclei are produced by stirring in the tank. This is advantageous because it is possible to cause the generation of particles, there is no need to add new nuclei, and the granulation is instantaneous due to the presence of the nuclei. The particle size of MTBT obtained by the present invention is
Although it can be freely changed depending on the type of stirring, the stirring speed, the amount of nuclei added, and the granulation temperature, a size of approximately 0.1 to 3 mm is generally preferred for practical purposes. Although the above explanation was made using MTBT as a representative example, the present invention can be applied as a method for producing granules of other organic rubber chemicals that are solid at room temperature. for example,
As a vulcanization accelerator, N-cyclohexyl-2-
Benzothiazole sulfenamide, 2-(4-
Thiazoles such as morpholinyldithio)benzothiazole, thioureas such as diethylthiourea and dibutylthiourea, anti-aging agents such as N-isopropyl-N'-phenyl-P-phenylenediamine, N-(1,3- dimethylbutyl)-N'-phenyl-P-phenylenediamine,
P such as mixed diallyl-P-phenylenediamine
-Applicable to phenylenediamine derivatives. EXAMPLES The present invention will be explained in more detail below with reference to Examples, Comparative Examples, and Test Examples, but the present invention is not limited thereto. Example 1 2480 parts by weight of water and nuclei [particle size 0.1
~0.3mm powder MTBT = Accel NS ^(*1) crushed product]
Add 56 parts by weight and raise the water temperature to 58~58 parts by weight while stirring at high speed.
MTBT (accelerator) heated and melted at 60℃
A solution prepared by dispersing 565 parts by weight of NS (melting point 81-85.5°C) in 857 parts by weight of water at 85°C with stirring was added over 15 minutes, immediately cooled, and dried at 55°C to form granules. 618 parts by weight were obtained. Its melting point was 81-85.5°C. The particle size distribution ratio of the obtained target product was measured using a wire mesh sieve, and the results were as shown in Table 1.

[Table] The particle size distribution ratio of granules with sizes ranging from 0.84 to 1.68 mm was 87%. (*1 is manufactured by Kawaguchi Chemical Industry Co., Ltd.) Example 2 The procedure of Example 1 was followed except that the amount of core added was 90 parts by weight, and 652 parts by weight of granules were obtained. Its melting point was 81-85.5°C. The particle size distribution ratio of the obtained target product was measured in the same manner as in Example 1, and the results were as shown in Table 2.

[Table] The particle size distribution ratio of granules with a size ranging from 0.5 to 1.0 mm was 78%. Example 3 The procedure of Example 1 was followed except that the stirring was changed to strong stirring, and 619 parts by weight of granules were obtained. Its melting point was 81-85.5°C. The particle size distribution ratio of the obtained target product was measured in the same manner as in Example 1, and the results are shown in Table 3.

[Table] The particle size distribution ratio of granules with a size ranging from 0.5 to 1.68 mm was 94%. Example 4 Example 1 was followed except that the granulation water temperature was maintained at 45 to 47°C, and 619 parts by weight of granules were obtained. Its melting point was 81-85.5°C. The particle size distribution ratio of the obtained target product was measured in the same manner as in Example 1, and the results are shown in Table 4.

[Table] The particle size distribution ratio of granules with sizes ranging from 0.5 to 1.68 mm was 82%. Example 5 42 parts by weight of water and kernels were added to a 100 stainless steel production grain tank.
Add 1.5 parts by weight and bring the water temperature to 58~58% while stirring at high speed.
Hold at 60℃. Next, heat and melt the
A dispersion prepared by dispersing 14.5 parts by weight of MTBT (Accel NS melting point 81-85.5°C) in 22 parts by weight of water (maintained at 85°C) with stirring is added over 20 minutes. Subsequently, a heated and melted MTBT aqueous dispersion having the same ratio as above is fed into the granulation tank at 109.5 parts by weight/hour. On the other hand, 55-60
℃ water was supplied into the granulation tank at 108 parts by weight/hour,
Maintain the granulation tank at 58-60°C. Note that new nuclei will not be supplied from outside. A part of the granules once granulated by the agitator in the granulation tank are crushed into small granules with a particle size of 0.35 mm or less. Use this as a core. The thus produced granule slurry was taken out at 217.5 parts by weight/hour, cooled, filtered, and dried at 55°C. The melting points of the granules collected after 30 minutes and 1 hour were both 81 to 85.5. It was warm at ℃.
The particle size distribution ratio of the obtained target product was measured using a wire mesh sieve, and the results were as shown in Table 5.

[Table] The particle size distribution of granules with a size ranging from 0.5 to 1.68 mm was 86% after 30 minutes and after 1 hour. Comparative Example 1 The procedure of Example 1 was repeated except that no cores were added, and 413 parts by weight of granules were obtained. Its melting point was 81-85.5°C. There was 150 parts by weight of ungranulated MTBT deposited on the stirring rod and beaker. The particle size distribution ratio of the target product obtained here is shown in Example 1.
The results measured in the same manner as above are shown in Table 6.

[Table] The particle size distribution ratio of granules with a size of 1.68 mm or more was 93%. Test Example 1 Comparison test of the angle of repose and disintegration rate of the granular product of the present invention and the flake product The angle of repose and disintegration rate of the granular product obtained in Example 2 of the present invention and the corresponding flake product (*2) A rate comparison test was conducted. The results are shown in Table 7.

【table】

[Table] The test results in Table 7 show that the granules of the present invention have better flowability than flake products and are granules that are less likely to disintegrate. Test Example 2 Dispersibility test of the granular product of the present invention in rubber A laboratory plasto mill (*5) was heated to 70°C, synthetic rubber BR01 (*6) was charged, and the example of the present invention was tested while rotating at 10 rpm. Add 0.5 phr each of the granular product No. 2 or the comparative sample (Accel NS) (*7),
A comparative test of dispersibility into rubber was conducted by rotating for 60 seconds. As a result, the granular product of Example 2 of the present invention was 60
It was completely dispersed into the rubber in seconds, and no particles were found even when observed using a microscope with a magnification of 20 times, and the dispersibility was exactly the same as that of the flake product. (*5): Manufactured by Toyo Seiki Seisakusho (*6): Manufactured by Japan Synthetic Rubber Co., Ltd. [ML ₁₊₄ (100℃) 44] (*7): Manufactured by Kawaguchi Chemical Industry Co., Ltd. Flake product test example 3 Granules of the present invention Vulcanization performance test of product The roll composition is based on the composition table in Table 8.
In accordance with JISK6300, the performance test of vulcanized rubber is
This was done in accordance with JISK6301. The result is the 9th
Shown in the table. Table 8 Compound Natural rubber (SMR-5) 100 parts by weight Zinc oxide (No. 1: manufactured by Mitsui Kinzoku Kogyo Co., Ltd.) 5 Stearic acid (manufactured by Nippon Oil & Fats Co., Ltd.) 3 HAF (Sheath #3: manufactured by Tokai Carbon Co., Ltd.)
50 Process oil (Sonic process oil R-200: manufactured by Kyodo Oil Co., Ltd.) 10 Sulfur (colloidal sulfur: manufactured by Hosoi Chemical Industry Co., Ltd.)
2.5 Test vulcanization accelerator 0.8

[Table] The test results in Table 9 show that the granular product of the present invention is equivalent to flake products in terms of vulcanization rate (times t ₅ and t ₃₅ ) and physical properties of the vulcanizate. be.

Claims (1)

[Claims] 1. In producing granules of organic rubber chemicals that are solid at room temperature, a heated melt of the organic rubber chemicals is used to produce powder of the same organic rubber chemicals as the melt. A method for producing granular organic rubber chemicals, characterized by stirring and granulating them in water added as a granulation aid. 2. The manufacturing method according to claim 1, wherein the granulation aid made of powder has a particle size of 0.5 mm or less. 3. The manufacturing method according to claim 1, wherein 0.5 to 30 parts by weight of a granulation aid made of powder is added to water per 100 parts by weight of the heated melt.