JP2004204126A - Method for granulating organic rubber chemical - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for granulating an organic rubber chemical, especially a vulcanization accelerator and improving the rubber dispersibility by the addition of a specific activation agent in the granulation process. <P>SOLUTION: The granulation of an organic rubber chemical such as mercaptobenzothiazol, dibenzothiazolyl disulfide, N-cycloheyl benzothiazyl-2-sulfenamide, tetramethyolthiuram disulfide, tetraethylthiuram disulfide and tetramethylthiuram monosulfide comprises the addition of a polyoxyethylene isodecyl ether having an HLB of 9.0-12.8 before granulation and the drying of the granulated product. A granulated product having unprecedentedly excellent thermal stability and rubber dispersibility can be produce by a new surfactant polyoxyethylene isodecyl ether into incorporating an organic vulcanization accelerator as the dispersing agent of the organic rubber chemical, especially an organic vulcanization accelerator for rubber. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
[Industrial applications]
The present invention relates to a method of granulating an organic rubber chemical, particularly a vulcanization accelerator, and a method of granulating with improved rubber dispersibility, characterized in that a specific activator is added during granulation, and granulation. About things.
[0002]
Organic rubber chemicals are often granulated for the purpose of automatic weighing, dust control and the like. Various methods have been devised for this granulation method, such as sticking and aggregating with an organic solvent, solidifying while cooling from a molten state into small particles, or pressing and molding a powder. However, these organic rubber chemicals need to be uniformly dispersed in the rubber at the time of kneading with the rubber on a roll or in a Banbury mixer when used.
[0003]
On the other hand, one of the factors related to rubber dispersion is the hardness of the granular material, and when the hardness is high, poor dispersion is caused. If the dispersion is not uniform in the rubber, the properties (heat resistance, flexibility, elongation, tear strength, scorch, vulcanization rate, etc.) of the rubber product will be adversely affected. Dispersibility is an important factor of quality.
[0004]
[Prior art]
[Patent Document 1] Published Patent Publication No. 55566/1981 [Patent Document 2] Published Patent Publication No. 16930/1986 [0005]
Patent Document 1 discloses a granulation method in which a sizing agent such as a polyoxyethylene alkyl ether is added to an organic rubber chemical in a range of 0.01 to 1% by weight. However, this document does not describe specific compounds.
[0006]
Similarly, in Patent Document 2, as a method for producing pellets that do not generate dust from powder, a polymer binder and a surfactant (a surfactant in the present application) composed of an alcohol or acid derivative of polyoxyethylene are used in combination. There is a description. Organic rubber chemicals are listed as applicable powders, and examples of polyoxyethylene oleyl ether are described as surfactants.
[0007]
[Problems to be solved by the invention]
At present, many of the commercially available rubber granules for rubber are extremely soft granules, taking into account the above-mentioned rubber dispersibility, and disintegrate during transportation to form powder or secondary agglomeration. As a result, not only is it unsuitable for automatic weighing at the time of use, but also there are many problems in working environment and safety and health due to dust.
[0008]
In addition, sulfenamide-based accelerators, which are organic vulcanization accelerators for rubber, are widely used in the rubber industry, but these compounds are unstable and have a high purity when exposed to high temperature or high humidity. Is known to decrease. It is also known that when an accelerator having a reduced purity is used for rubber vulcanization, the vulcanization characteristics of the rubber change.
[0009]
Configuration of the Invention
The present inventors have conducted intensive studies and, as a result, in the commercialization of organic rubber chemicals exemplified by organic vulcanization accelerators for rubber, pulverize the compound if necessary, and then add the nonionic surfactant By adding and granulating a polyoxyethylene isodecyl ether in the range of 9.0 to 12.8 among the polyoxyethylene isodecyl ethers, a granulated product having little disintegration and excellent dispersibility can be obtained. Was found. In particular, by applying the above-mentioned surfactant to a sulfenamide-based accelerator which is an organic vulcanization accelerator for rubber, even when exposed to a high temperature or high humidity state, the purity is stabilized without being reduced. I also found that.
[0010]
The present invention has a feature similar to that of Patent Document 1 described above, except that the use of a specific activator and a limited HLB range are employed. . By the way, a surfactant has a hydrophilic group and a hydrophobic group having a certain structural size in a molecule, thereby exhibiting various surface chemical properties. The HLB (Hydrophile-Lipophile Balance) indicates the degree of the balance between the hydrophilicity and the hydrophobicity.
[0011]
Here, the present invention will be described. Even with the same polyoxyethylene isodecyl ether-type surfactant, if the HLB is less than 9.0, the surface of the granulated product becomes lipophilic, and the surface modifying effect of the granulated product becomes insufficient, The phenomenon that the hardness of the granulated product becomes soft occurs, which is not preferable in terms of dispersibility. On the other hand, if the HLB exceeds 12.8, the hydrophilicity becomes strong, the compatibility between the rubber and the organic organic chemicals for rubber, especially the granulated product which is a vulcanization accelerator, becomes poor, and the workability in the molding process becomes poor. It is not preferable because the granulation product does not have an optimum granulation hardness, such as an increase in cracking.
[0012]
Examples of the organic rubber chemicals to which the present invention can be applied include a vulcanizing agent, a vulcanization accelerator, and an antioxidant, and specific examples thereof include a vulcanization accelerator. Examples of applicable vulcanization accelerators include thiazoles such as mercaptobenzothiazole and dibenzothiazolyl disulfide, N-tert-butylbenzothiazyl-2-sulfenamide, N-cyclohexylbenzothiazyl-2-sulfene. Examples include sulfenamide-based accelerators such as amides and thiuram-based accelerators such as tetramethylthiuram disulfide, tetraethylthiuram disulfide and tetramethylthiuram monosulfide. It should be noted that other organic vulcanizing agents, vulcanization accelerators and anti-aging agents can of course be applied.
[0013]
[Action]
In the practice of the present invention, the amount of the surfactant added is preferably 0.05 to 1% by weight of the vulcanizing agent, the vulcanization accelerator, and the weight of the organic rubber chemical exemplified by the antioxidant. Percent, more preferably 0.3-0.5 weight percent. Addition of less than 0.05% by weight has little effect on processability during granulation and dispersibility in rubber. Addition of more than 1% by weight makes the hardness during granulation molding too soft, and is not economically preferable. Further, in a specific rubber, there is a problem that excess surfactant causes bloom in the rubber.
[0014]
The amount of the surfactant to be added is preferably changed within the above-mentioned range and appropriately varied depending on the specific gravity and the desired hardness required for the rubber chemical. The surfactant of the present invention can be mixed with a dry or wet organic rubber chemical in a liquid state. Alternatively, the surfactant may be made into a solution having an appropriate concentration and then mixed. The granulation method can be carried out by any of a batch method and a continuous method, and the method is preferably ordinary extrusion molding or tablet molding.
[0015]
Further, if necessary, for the purpose of improving the dispersibility of the granular product in the rubber, a process oil such as a naphthenic oil, an aromatic oil, a paraffin oil, or a paraffin wax, which is usually added during rubber processing, may be used. A plasticizer such as a fatty acid ester may be added to the granulated product.
[0016]
【Example】
Hereinafter, examples of the present invention will be described, but the scope of the present invention is not limited thereto.
Example 1
To 400 g of N-cyclohexylbenzothiazyl-2-sulfenamide (hereinafter referred to as CM in the examples) having a water content of 30%, polyoxyethylene isodecyl ether (Neugen SD-30 HLB 10.0 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) After mixing 1.4 g, further adding 20 g of water and kneading sufficiently, the mixture was granulated by an extrusion granulator, and dried by a ventilation dryer at 80 ° C. to obtain 280 g of a granulated product. The quality of the granulated product was evaluated by the following method. The results are also described.
[0017]
1 Rubber Dispersion Test 5 g of a granulated product is added to a mixed rubber of 50 g of butadiene rubber and 50 g of EVA (ethylene vinyl acetate copolymer), kneaded on a roll for 1 minute, cut back for 1 minute, and tightly milled. The number of CM-dispersion-defective particles in the tight-through sheet was visually measured. The number of poorly dispersed particles in the granulated product was 0.
[0018]
2 Hardness Hardness is a load required to break a granulated product, is measured according to the method of JIS K6219 (1997), and the hardness of the particles is calculated by a calculation method described in JIS. As a result of measuring the hardness of the granulated product, the average hardness was 42 g. In addition, since a decrease in hardness causes an increase in the powdering ratio to be tested as described below, and an increase in hardness affects the rubber dispersion described above, a preferable average hardness of a normal rubber chemical is 30 to 50 g.
[0019]
3 Powdering Rate 10 g of the granulated product was placed in a 60-mesh sieve and vibrated for 10 minutes, and the powdering ratio was calculated from the weight difference of the granulated product remaining in the sieve. The result was 0.02%.
4. Thermal Stability Measurement Method A heat aging test was conducted by placing 30 g of a granulated product in a closed glass bottle and leaving it in a thermostat at 40 ° C. for 3 months. The purity was measured by a titration method before and after the test, and the stability of quality was evaluated based on the difference in the purity. As a result, the purity before the test was 98.8%, and the purity after the test was 96.8%, indicating excellent thermal stability with a purity change rate of 0.9% after 3 months. In addition, this test was implemented about CM which is a sulfenamide type vulcanization accelerator which has a thermal decomposition property.
[0020]
Example 2
1.4 g of polyoxyethylene isodecyl ether (Neugen SD-60 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) having an HLB of 12.0 was added to 400 g of CM having a water content of 30%, and 20 g of water was further added. The mixture was granulated by a granulator and dried by a ventilation dryer at 80 ° C. to obtain 280 g of a granulated product. Each test described in Example 1 was performed. As a result, in the rubber dispersion test, the number of defective dispersion was 0, the average hardness was 44 g, the powdering rate was 0.02%, and the purity change rate was 1.1%.
[0021]
Example 3
1.3 g of polyoxyethylene isodecyl ether (Neugen SD-60 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) having an HLB of 12.0 was mixed with 400 g of mercaptobenzothiazole having a water content of 22%, and 20 g of water was further added and kneaded sufficiently. Thereafter, the mixture was granulated by an extrusion granulator and dried by a ventilation dryer at 80 ° C. to obtain 310 g of a granulated product. Each test described in Example 1 was performed. As a result, the number of poor dispersion in the rubber dispersion test was 0, the average hardness was 30 g, and the powdering ratio was 0.03%.
[0022]
Example 4
To 400 g of tetramethylthiuram monosulfide having a moisture content of 25%, 1.2 g of HLB 10.0 polyoxyethylene isodecyl ether (Neugen SD-30 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was added, and 20 g of water was further added to the mixture. After kneading, the mixture was granulated by an extrusion granulator and dried by a ventilation dryer at 80 ° C. to obtain 298 g of a granulated product. Each test described in Example 1 was performed. As a result, the number of poor dispersion in the rubber dispersion test was 0, the average hardness was 34 g, and the powdering ratio was 0.02%.
[0023]
Example 5
To 400 g of dibenzothiazolyl disulfide having a water content of 25%, 1.2 g of polyoxyethylene isodecyl ether having a HLB of 12.6 (Neugen SDX-60 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was added, and 20 g of water was further added thereto. After kneading, the mixture was granulated by an extrusion granulator and dried by a ventilation dryer at 80 ° C. to obtain 302 g of a granulated product. Each test described in Example 1 was performed. As a result, the number of defective dispersions in the rubber dispersion test was 3, the average hardness was 32 g, and the powdering ratio was 0.02%.
[0024]
Comparative Example 1
20 g of water was added to 400 g of CM having a water content of 30%, kneaded, kneaded, granulated by an extrusion granulator, and dried by a ventilation dryer at 80 ° C. to obtain 280 g of a granulated product. Each test described in Example 1 was performed. As a result, the number of defective dispersions in the rubber dispersion test was 20, the average hardness was 15 g, the powdering rate was 1.8%, and the purity change rate was 3.0%. As compared with Examples 1 and 2 of the present invention, rubber dispersibility, average hardness and powdering ratio were inferior to the present invention.
[0025]
Comparative Example 2
1.4 g of polyoxyethylene isodecyl ether of HLB 13.0 (manufactured by Neugen SD-70 Daiichi Kogyo Seiyaku Co., Ltd.) was added to 400 g of CM having a water content of 30%, and 20 g of water was further added. The mixture was granulated by a granulator and dried by a ventilation dryer at 80 ° C. to obtain 280 g of a granulated product. Each test described in Example 1 was performed. As a result, the number of defective dispersions in the rubber dispersion test was 10, the average hardness was 25 g, the powdering rate was 0.4%, and the purity change rate was 4.0%.
This example is a surfactant of the same type as the present invention having an HLB value higher than 12.8, but is inferior in rubber dispersibility, average hardness, powdering rate, and thermal stability as compared with Examples 1 and 2. .
[0026]
Comparative Example 3
To 400 g of mercaptobenzothiazole having a water content of 22%, 1.3 g of polyoxyethylene tridecyl ether having a HLB of 12.0 (Neugen TDS-70, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was added. After kneading, the mixture was granulated by an extrusion granulator and dried by a ventilation dryer at 80 ° C. to obtain 310 g of a granulated product. Each test described in Example 1 was performed. As a result, the number of defective dispersions in the rubber dispersion test was 10, the average hardness was 25 g, and the powdering ratio was 1.2%. Compared with Example 3 of the present invention, rubber dispersibility, average hardness and powdering ratio were inferior to the present invention.
[0027]
Comparative Example 4
280 g of a granulated product was obtained in the same manner as in Comparative Example 2, except that the activator was changed to a polyoxyethylene alkyl ether of HLB 10.5 (Emulgen 705, manufactured by Kao Corporation). Each test described in Example 1 was performed. As a result, the number of defective dispersions in the rubber dispersion test was 9, the average hardness was 41 g, the powdering rate was 0.02%, and the purity reduction rate was 6.5%. As compared with Example 1 of the present invention, the same average hardness and powdering ratio were shown, but rubber dispersibility and thermal stability were inferior to the present invention.
[0028]
【The invention's effect】
The effect of the present invention is as follows. Among polyoxyethylene isodecyl ethers, which are novel surfactants as dispersants for organic rubber chemicals, especially organic vulcanization accelerators, HLB 9.0 to 12.8 activators can be used. It is an object of the present invention to provide a granulated organic rubber chemical having excellent thermal stability and rubber dispersibility, which has never been obtained before, by adding it to an organic rubber chemical such as a vulcanization accelerator.

Claims (5)

A method of granulating an organic rubber chemical, comprising adding a polyoxyethylene isodecyl ether having an HLB of 9.0 to 12.8 in the granulation of the organic rubber chemical. 2. The granulation method according to claim 1, wherein the organic rubber chemical is a vulcanizing agent, a vulcanization accelerator or an anti-aging agent. The vulcanization accelerator is mercaptobenzothiazole, dibenzothiazolyl disulfide, N-tert-butylbenzothiazyl-2-sulfenamide, N-cyclohexylbenzothiazyl-2-sulfenamide, tetramethylthiuram disulfide, tetraethylthiuram The granulation method according to claim 2, wherein the granulation is one or more selected from disulfide and tetramethylthiuram monosulfide. The granulation method according to any one of claims 1 to 3, wherein the amount of the polyoxyethylene isodecyl ether added is 0.05 to 1% by weight of the organic rubber chemicals. A granulated product produced by the granulation method according to claim 1.