JPH06864B2 - Rubber composition - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to a rubber composition. More specifically, it relates to a rubber composition of natural rubber and / or synthetic rubber for the purpose of improving the vulcanization activity of rubber.

[Problems to be Solved by the Invention]

Conventionally, organic vulcanization activators at the time of vulcanization of rubber include organic amines such as mono- or diethanolamine, dibutylamine and dicyclohexylamine, glycols such as ethylene glycol and diethylene glycol, dibutylammonium oleate and ethylene glycol. Ammonium salts such as dicyclohexyl ammonium salt are known. However, most of these conventional vulcanization activators have a liquid or deliquescent property, so that weighing, compounding, kneading and other work operations are inconvenient and vulcanization varies. The thing which improved this point and improved handling was the addition product of dicyclohexylamine and a polyol. However,
This substance has sublimation properties, and it is expected that the exterior will be contaminated during storage and further the entire storage will be contaminated.Therefore, strict control is required, and at the time of its use, when it is added during rubber processing. In addition, the sublimation of the rubber material becomes more intense due to heat generation or heating of the rubber material during kneading, which causes deterioration of the working environment. In addition, the effect on rubber is that the amount of additive added by sublimation is not constant, the vulcanization characteristics are constantly changing, making it difficult to control the vulcanization process, resulting in inevitable variations in the molded rubber. Was there.

[Means for solving the problem]

The present inventors have conducted extensive studies in view of the above circumstances, and as a result, a rubber derivative comprising a phenol derivative represented by the following general formula, or an adduct thereof with dicyclohexylamine, and a natural rubber and / or a synthetic rubber. The inventors have found that the composition has excellent vulcanization activity, and have reached the present invention. (In the formula, R is a lower alkyl group, methoxy group, n is 0 to 2
The stands, X _{is, - (CH 2) p-} O- (CH 2) p- or _{- (CH 2) p-O} -CH 2 -O- (CH 2) a p-, wherein p is 1 Is an integer of ˜3. ) Specific examples of the above-mentioned phenol derivative described in the present invention include 1,5-bis (4-hydroxyphenylthio) -3.
Examples include -oxapentane, 1,7-bis (4-hydroxyphenylthio) -3,5-dioxaheptane and 1,8-bis (4-hydroxyphenylthio) -3,5-dioxaheptane. The rubber applicable to the composition of the present invention is not particularly limited, and examples thereof include natural rubber and isoprene rubber, butadiene rubber, styrene-butadiene rubber, ethylene-propylene rubber, acrylonitrile-butadiene rubber, chloroprene rubber, and other synthetic rubbers. , Or blended rubbers thereof. The method for producing the composition of the present invention is also not particularly limited.
For example, a method of dry blending with a roll or a Banbury, a method of preparing an aqueous dispersion of a phenol derivative in advance, and mixing the solution in a latex latex of rubber can be adopted.

[Action]

In the rubber composition according to the present invention, the amount of the phenol derivative or the adduct of the phenol derivative or dicyclohexylamine is preferably about 0.1 to 5 parts, more preferably 0.5 to 2 parts, based on 100 parts of the rubber content. It is a department. The composition of the present invention further comprises a vulcanizing agent, a vulcanization accelerator, an activator,
An unvulcanized rubber can be obtained by adding and mixing an appropriate auxiliary agent such as a filler, a reinforcing agent, an antiaging agent, a spreading agent, and a coloring agent. This unvulcanized rubber mixture is vulcanized by vulcanizing by a conventional method such as thermal vulcanization or high frequency vulcanization. This vulcanization method can be appropriately selected and applied according to the purpose. In the present invention, only dicyclohexylamine is mentioned as the adduct. Although other basic substances such as guanidine, 1,3-diphenylguanidine and other guanidine derivatives, and naphthylamine-based and p-phenylenediamine-based antiaging agents form adducts and exert excellent effects, these Since all of them are solids, they can be added to the rubber independently without forming a salt, and are not desirable for use in consideration of the contamination of the above amines other than dicyclohexylamine with the rubber. As described above, the composition of the present invention has the following advantages and is extremely significant industrially. The first feature is that the phenol derivative of the present invention or an adduct thereof with dicyclohexylamine is a natural rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, ethylene-propylene rubber,
This is because the vulcanization can be activated by additionally using a vulcanization accelerator in a composition with a synthetic rubber such as acrylonitrile-butadiene rubber or chloroprene rubber. The second feature is that the phenol derivative in the composition of the present invention or the adduct of this with dicyclohexylamine is a solid at room temperature, and is easy to handle when compounding with rubber. Thirdly, the phenol derivative itself in the composition has an antiaging effect on rubber (JP-A-62-172087).
No.), the aging resistance of the vulcanized rubber is improved.

【Example】

Experimental examples and examples will be described below. Experimental Example 1 About 5 g of the sample phenol derivative and the sample of the following comparative example were precisely weighed in a glass petri dish having a diameter of 5 mm and a depth of 20 mm.
The sample was left to stand in a constant temperature bath at 150 ° C. for a predetermined time, and the weight loss of each sample was obtained from the following equation. The results are shown in Table 1. Assuming that the sample weight before the heat treatment is A and the sample weight after the heat treatment is B, weight loss (%) = (A−B) ÷ A × 100 BOH in this example is 1,7-bis ( 4-hydroxyphenylthio) -3,5-dioxaheptane, and BOH DCHA means a 1,7-bis (4-hydroxyphenylthio) -3,5-dioxaheptane / dicyclohexylamine adduct. In addition, the comparative example EG
DCHA refers to an ethylene glycol dicyclohexylamine adduct. Experimental Example 2 Approximately 10 g of the test phenol derivative and the sample of the following comparative example were precisely weighed in a glass petri dish having a diameter of 95 mm and a depth of 20 mm, left at room temperature in a desiccator containing water, and taken out at predetermined intervals and weighed. , Weight increase by the following formula (moisture absorption rate)
Was obtained and the results are shown in Table 2. When the sample weight before standing is C and the sample weight after standing is D, weight loss (%) = (D−C) ÷ C × 100 Example 1 The effective compounding ratio for rubber is shown in Table 3. Kneading is 6φ x
Using a 12'L test roll and a roll temperature of 50 ± 5 ° C., a conventional kneading method was used. Mooney scorch test results at 125 ° C (ML ₁
(125 ° C.) is shown in Table 4. The press vulcanization test at 140 ° C. is shown in Table 5. In addition, in Table 3, sun cellar D
M is the trade name of dibenzothiazyl disulfide manufactured by Sanshin Chemical Industry Co., Ltd. Example 2 Testing was carried out according to Example 1. The composition is shown in Table 6 and 12
Mooney scorch test results at 5 ° C (ML ₁ 12
The results of the press vulcanization test at 145 ° C. × 20 minutes, the heat aging test result of the rubber at 100 ° C. × 96 hours, and the colorability / discoloration test results are summarized in the seventh section.
Shown in the table. In Table 6, sun cellar H is a trade name of hexamethylenetetramine manufactured by Sanshin Chemical Industry Co., Ltd.). In addition, as the evaluation criteria of the colorability and discoloration, one having no discoloration is 1, yellow-brown is 5 and intermediate color is 2 to 4,
The comparison was made visually. Example 3 The test was carried out according to Example 1. The composition is shown in Table 8 and 12
Mooney scorch test results at 5 ° C (ML ₁ 12
5 ° C.) is shown in Table 9, and the press vulcanization test result at 140 ° C. × 15 minutes and the heat aging test result at 100 ° C. × 96 hours of the rubber are shown in Table 10. The eighth
In the table, Sanseller CM is a trade name of N-cyclohexylbenzothiazyl-2-sulfenamide manufactured by Sanshin Chemical Industry Co., Ltd.

【The invention's effect】

As is clear from the examples, when this composition is used in combination with a vulcanization accelerator, it markedly activates the vulcanization of rubber and makes it possible to shorten the vulcanization time. Therefore, the operating rate of the vulcanization facility is improved, and the facility cost can be reduced. Further, it is understood that the physical properties of the vulcanized rubber product are improved by increasing the aging resistance of the vulcanized rubber, and it is clear that the composition of the present invention is extremely useful industrially.

Claims (1)

[Claims] 1. A phenol derivative represented by the following general formula,
Alternatively, a rubber composition comprising an adduct of this and dicyclohexylamine, and natural rubber and / or synthetic rubber. (In the formula, R is a lower alkyl group, methoxy group, n is 0 to 2
And X is-(CH ₂ ) p-O-CH ₂ -O- (CH ₂ ) p- or-(C
_{H 2) p-O- (CH} 2 -O-CH 2) a p-, wherein p is an integer of 1 to 3. )