JPS6312493B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel anti-aging agent for rubber and a method for producing the same, and more specifically, the present invention relates to a novel anti-aging agent for rubber and a method for producing the same. triazinethio compound with one or two bonds,
The present invention relates to a novel anti-aging agent for rubber comprising a triazine dithio compound or a triazine trithio compound, and a method for producing the same. In the following description, the term triazinethio compound, triazine dithio compound or triazine trithio compound shall have the above meaning. Due to recent changes in automobile fuels and engine systems due to resource conservation, combined deterioration of rubber products used in this field has become a major problem, and anti-aging agents are added to rubber products even at high temperatures and/or in contact with solvents. There is a need for something that will not volatilize or be extracted. For this reason, there is an increasing demand for a so-called reactive anti-aging agent that imparts reactivity to the anti-aging agent and chemically bonds with the rubber during vulcanization. The inventor has already expressed the formula () Synthesize a compound in which an antioxidant group such as -NHC ₆ H ₄ NHC ₆ H ₅ is introduced into R of the 1,3,5-triazine ring as shown in , and R' is R or SH,
The combined use of this compound and dibenzothiazyl disulfide has revealed its action as a reactive anti-aging agent [Journal of the Japan Rubber Association, Vol. 49, No. 9712 (1976), Vol. 50, No. of the same journal. 8548 pages (1972)]. As a result of subsequent research, the present inventor discovered that 6-R-1,3,5-triazine-2 of formula (),
4-dithiol or 6-R-4-R-1,3,5
-Thioamine groups, dithioamine groups, and trithioamine groups that are more reactive toward unsaturated rubber than the thiol group of thiol-containing triazine having an antioxidant group (R) such as triazine-2-thiol are substituted with thiol groups. formula() {In the formula, R ₁ is -NHC ₆ H ₄ NHC ₆ H ₅ , -N(C _n
H _2n+1 ) C ₆ H ₄ NHC ₆ H ₅ (m is an integer from 3 to 8), -
NHC ₆ H _4-p (tert-C ₄ H ₉ ) _p OH (p is an integer from 1 to 2)
as well as

[Formula] _{represents a} group, _{R 2 is} R _{1 or -S} 5 integer) or

A triazinethio compound, a triazine dithio compound or a triazine trithio compound represented by
The present invention has been achieved based on the discovery that it is useful as a new reactive anti-aging agent for rubber. When the compound of formula () of the present invention is kneaded into unsaturated rubber, its one or two thioamine groups, dithioamine groups or trithioamine groups decompose at the vulcanization temperature of the rubber and easily form the unsaturated rubber. It has the characteristic of forming side chains or crosslinked chains by reacting with As a result, the antioxidant group such as R ₁ substituted on the triazine ring chemically bonded to the rubber does not volatilize or elute even at high temperatures or in contact with a solvent, and can maintain its antioxidative properties. Since the triazine ring contains three highly electronegative nitrogen atoms, the ring carbons are particularly strongly positively polarized. Therefore, the sulfur negativity of the thiol group bonded to this carbon is significantly lower than that of general thiol groups. Therefore, it is possible to introduce thioamine groups, dithioamine groups, and trithioamine groups, which were considered difficult to synthesize in the past, and it is expected that compounds of formula () containing thioamine groups, dithioamine groups, and trithioamine groups can be obtained in a stable state. . The present inventor skillfully applied this property to produce 1,3,5-
triazinethiol compound and N-chloramine,
By condensation with thiobisamine or dithiobisamine, a hitherto unknown triazinethio compound, triazine dithio compound, or triazine trithio compound could be stably obtained. The synthesis reaction of the compound of the formula () of the present invention is as shown in the above reaction formulas (A), (B) and (C), and the _1,3,5- It proceeds stoichiometrically by adding a solution of a triazinethiol or dithiol in a water-soluble organic solvent (alcohol, acetone, tetrahydrofuran, etc.) to a similar solution of a common N-chloroamine, thiobisamine or dithiobisamine. At this time,
Hydrochloric acid produced as a by-product in the above reaction formula (A) is neutralized and removed, for example, with caustic soda added in advance. Furthermore, the amines produced as by-products in formulas (B) and (C) need to be neutralized and removed, for example, with dilute hydrochloric acid. Also, when using a solution of a non-aqueous solvent such as methylene chloride or trichloroethylene, add dilute hydrochloric acid in an amount calculated to neutralize the entire amount of amine expected to be a by-product, and allow the whole to react while stirring. Therefore, all by-produced amines migrate to the aqueous layer as hydrochloride and can be excluded from the reaction system. In addition to thiobismorpholine, thiobisamines used in reaction formula (B) include thiobis(dibutylamine), thiobis(dioctylamine),
Thiobis (dipropylamine), Thiobis (dicyclohexylamine), Thiobis (piperidine)
In addition to dithiobismorpholine, dithiobisamines used in reaction formula (C) include dithiobis(dibutylamine), dithiobis(dioctylamine), dithiobis(dipropylamine), dithiobis(dicyclohexylamine), dithiobis (piperidine), etc. In addition to N-chloromorpholine, N-chlorobutylamine and the like are commonly used as N-chloramines used in reaction formula (A), but the present invention also includes other N-chloroamines. , monothiobisamine and dithiobisamine are all included. Next, the thioamine type obtained by the present invention,
Representative compounds of dithioamine type and trithioamine type are shown in Tables 1, 2 and 3.

【table】

【table】

[Table] Unsaturated rubbers to which the compound of the present invention can be applied as anti-aging agents for rubber include natural rubber,
All unsaturated rubbers such as styrene butadiene rubber (SBR), butadiene rubber (BR), isoprene rubber (IR), acrylonitrile butadiene rubber (NBR), chloroprene rubber (CR), ethylene propylene terpolymer (EPDM), etc. alone or in combination I can give you some rubber. In particular, when used for styrene-butadiene rubber, butadiene rubber, acrylonitrile-butadiene rubber, etc., excellent anti-aging effects are exhibited. The amount of the anti-aging agent of the present invention added to the rubber is:
Although it varies depending on the type of rubber added, it is 0.1 to 30 parts by weight, preferably 0.5 to 10 parts per 100 parts of rubber.
It is better to add some. Further, the anti-aging agent of the present invention can be used alone or in combination of two or more, and can also be used in combination with known anti-aging agents. The anti-aging agent of the present invention can be cured by any vulcanization method using not only sulfur but also organic sulfur compounds, amines, metal oxides, oxime compounds, and resin vulcanizing agents. Furthermore, any known vulcanization accelerator, reinforcing agent, filler, etc., which are other rubber compounding agents, can be used in combination. The anti-aging agent of the present invention can be added to rubber by a conventionally known addition method, such as by using a compounding roll. Examples and test examples will be described below to concretely demonstrate the effects of the present invention, but the present invention is not limited to the above description and the following examples. Various changes are possible according to the purpose. For example, although one method for producing the novel anti-aging agent of the present invention has been described above, the anti-aging agent of the present invention is not limited to that produced by the above-mentioned production method; Of course, products obtained by any production method that may be used are included in the present invention. Example 1 (Production example of No. 1 in Table 1) 2-R ₁ -1,3,5-triazine-4,6-
Dithiol (R ₁ = -NHC ₆ H ₄ NHC ₆ H ₅ ) 3.27 g
Dissolve 0.8 g of caustic soda in 50 ml of aqueous solution. This was mixed with 50 ml of a chloroform solution of 2.43 g of N-chloromorpholine, and after reacting at 30°C for 2 hours, the chloroform layer was dehydrated with anhydrous sodium sulfate, and when the chloroform was distilled off, the target crude compound No. 1 in Table 1 was obtained. Yield 95
Obtained in %. A chloroform solution (5 ml, 20%) of this crude compound was purified through a silica gel column (developing solution: chloroform, 50 g of silica gel). Melting point 146-147℃ Analysis value (%) S: 12.7 (12.88), N: 19.3 (19.72) However, ( ) is calculated value Example 2 (Production example of No. 1 in Table 2) 2-R _{1 -1,} 3, 5-triazine-4,6-
Dithiol (R ₁ = -NHC ₆ H ₄ NHC ₆ H ₅ ) 3.27 g
and 4.08g of thiomorpholine in chloroform (50ml)
In addition to this, an aqueous solution (50 ml) containing 2.4 g of acetic acid.
Mix and stir at 40°C for 3 hours. After thoroughly washing the chloroform layer with water and dehydrating it with anhydrous sodium sulfate, the chloroform was distilled off under reduced pressure to obtain the target crude compound No. 1 in Table 2 in a yield of 95%. Purification was carried out in Example 1.
I did the same thing. Melting point 102-103℃ Analysis value (%) S: 22.7 (22.82) N: 17.4 (17.47) However, ( ) is calculated value Example 3 (Production example of No. 1 in Table 3) 4,6-Bis R ₁ -1 ,3,5-triazine-
2-thiol [R ₁ =-N(i-C ₃ H ₇ )
Dissolve 5.6 g of C ₆ H ₄ NHC ₆ H ₅ in 50 ml of methylene chloride and stir with 30 ml of 1N acetic acid. After adding 2.4 g of dithiobismorpholine to the mixture over 30 minutes with stirring, the mixture was further stirred under reflux for 2 hours. The methylene chloride layer was separated, washed with water, and dried over anhydrous sodium sulfate. The methylene chloride was distilled off under reduced pressure to obtain 6.3 g of the desired crude compound No. 1 in Table 3. Purification was carried out in the same manner as in Example 1. Melting point 89-90℃ Analysis value (%) N: 15.0 (15.8), S: 13.5 (13.5) However, ( ) is calculated value Example 4 (Table 3 No. 6 Manufacturing example) 2-R _{1 -1} , 3, 5-triazine-4,6-
Add 3.3 g of dithiol (R ₁ =-NHC ₆ H ₄ NHC ₆ H ₅ ) and 4.7 g of dithiomorpholine to chloroform (50 ml).
In addition to this, an aqueous solution (50 ml) containing 2.4 g of acetic acid.
After stirring at 20℃ for 3 hours, the chloroform layer was thoroughly washed with water, dehydrated with anhydrous sodium sulfate, and the chloroform was distilled off under reduced pressure to obtain the desired product, Table 3 No. 6.
The crude compound was obtained in 95% yield. Purification was carried out in the same manner as in Example 1. Melting point 81-82℃ Analysis value (%) S: 30.2 (30.70), N: 15.5 (15.68) However, ( ) is calculated value Example 5 (Production example of No. 7 in Table 3) 2-R _{1 -1,} 3, 5-triazine-4,6-
Dithiol

Add 4.1 g of [Formula] and 4.7 g of dithiomorpholine to 50 ml of methylene chloride, add 40 ml of 1N acetic acid, and stir at 20°C for 3 hours. The methylene chloride layer was separated, washed with water, dried over anhydrous sodium sulfate, and then the methylene chloride was distilled off under reduced pressure to obtain 6.5 g of the desired crude compound No. 7 in Table 3. Purification was carried out in the same manner as in Example 1. Melting point 85-86℃ Analysis value (%) N: 13.6 (13.9), S: 27.0 (27.4) However, ( ) is a calculated value test example Reactivity of the main compound obtained in the present invention to unsaturated rubber is shown. 4. In both cases, when heated rubber is extracted with a solvent for a long time, the compound of formula () in the comparative example has a residual rate of 0% when used alone, and even when used in combination with MBTS, the residual rate is as low as 18%, but the compound of the present invention does not remain. The fact that the ratio is high and most of it remains without being extracted with the rubber indicates that it has a strong chemical bond with the rubber.

[Table] Examples 6-7 and Comparative Examples 1-2 Compound SBR1502 100 parts SRF Black 50〃 Zinc white 5〃 Stearic acid 1〃 Vulcanizing agent Table 5 Vulcanization accelerator〃 Anti-aging agent 〃 The above formulation Compounded according to JISK-6383,
It was press-vulcanized at 155°C for 30 minutes and used as a rubber physical test sample. This rubber physical test sample was subjected to a rubber physical test in accordance with JIS K-6301. Quantity symbols for physical tests were based on SRIS3101.

[Table] The results in Table 5 are based on No. 3 in Table 3, which is a compound of the present invention.
The vulcanized rubber containing No. 5 and No. 6 was the comparative example.
Compared to vulcanized rubber containing IPPD and the compound of formula (), it shows the same or better heat resistance. In particular, it has excellent heat resistance because there is little deterioration after solvent extraction. This reveals that the compounds of the present invention are excellent antiaging agents with high non-extractability to solvents by combining with SBR. Examples 8 to 11 and Comparative Example 3 Compound NBR230S 100 parts SRF Black 50〃 Zinc white 5〃 Stearic acid 1〃 Plasticizer DOP 30〃 Vulcanization accelerator Table 6 Vulcanizing agent〃 Anti-aging agent〃 Blend of the above formulation The vulcanization and vulcanization were conducted in accordance with JIS K-6384, and the rubber physical test was conducted in the same manner as in Example 6.

[Table] From the results in Table 6, it was found that the compounds in Table 2, which are the compounds of the present invention,
No. 1, No. 5 and No. 6 in Table 3 are blended with it.
Even before solvent extraction of NBR vulcanizate, the comparative example
It is clear that it has excellent heat anti-aging properties equivalent to IPPD, and especially regarding the effect after solvent extraction, by combining with NBR, it maintains high non-extractability against solvents and is resistant to heat aging. It is clear that this provides a rubber composition with extremely high resistance. Example 12 (Anti-aging effect based on oxygen absorption test) Compounded in the same manner as Examples 9 to 11 and Comparative Example 3 (however, the SRF black and plasticizer DOP were excluded), and pressed under the same conditions. sulfur and thickness
A 0.5 mm vulcanized rubber composition was obtained. This vulcanized rubber composition was cut out into a 5 mm x 20 mm test piece and used as a measurement sample. Each of the measurement samples was divided into two parts, and one of the samples was placed in a Soxhlet type extractor and extracted using an azeotropic mixed solvent with a volume ratio of methanol/acetone/chloroform = 28/35/29 for 4 days. It was used as a sample. Next, after weighing both the unextracted sample and ^the extracted sample, 145
The anti-aging effect of the sample anti-aging agent was determined by measuring the amount of oxygen absorbed at ℃. The results are shown in Figure 1 of the attached drawings. As can be seen from FIG. 1, compounds of the present invention, No. 5 ((A) line) and No. 6 ((B) line) in Table 3, were used before solvent extraction of the vulcanizate containing them ( It is clear that IPPD (solid line) has a better effect than the comparative example IPPD (line (C)), and as for the effect after solvent extraction (broken line), it is clear that by combining with NBR, the solvent It is clear that this provides a rubber composition that retains high non-extractable performance against oxidative deterioration and is extremely resistant to oxidative degradation. Note: ⁽⁹⁾ : Compliant with Rubber Test Method P392-7.1.3 Oxygen Absorption Measurement Method. (Published by Japan Rubber Association on November 1, 1982) Example 13 and Comparative Example 4 Compound JSR E601 ⁽¹⁰⁾ 100 parts (NBR/EPDM=60/40 Zinc white 5 Stearic acid 1 Sulfur Yellow Table 7 Vulcanization accelerator [Anti-aging agent] The formulation, vulcanization and physical tests of the above formulation were carried out in the same manner as in Example 8.

【table】

[Table] From the results in Table 7, it was found that the compounds in Table 3, which are the compounds of the present invention,
No. 2 shows that even before solvent extraction of the vulcanizate containing it, it has excellent heat anti-aging properties equivalent to or better than the comparative example DNPD. In particular, regarding the effect after solvent extraction, it is shown that compared to the comparative example DNPD, it maintains high non-extraction performance against solvents and provides a rubber composition with extremely high resistance to heat aging. . Example 14 and Comparative Example 5 Compound NBR230S 150 parts Zinc white 5 Stearic acid 1 Vulcanization accelerator Table 8 Anti-aging agent The formulation, vulcanization and rubber physical test of the above formulation were conducted in the same manner as in Example 8. Summer.

[Table] The results in Table 8 of Example 14 show that the compound No. 4 in Table 3, which is a compound of the present invention, has a heat aging resistance equal to or higher than that of the comparative example DTBMP even before solvent extraction of the vulcanizate containing it. This shows that the compound No. 4 in Table 3, which is a compound of the present invention, has a rubber composition with high resistance to heat aging, especially after solvent extraction, compared to the comparative example DTBMP. It shows giving. As can be seen from the above examples, the novel anti-aging agents for rubber of the present invention are hardly volatilized or extracted even when rubber products containing them are exposed to high temperatures or come into contact with solvents. , it is possible to provide rubber products with performance that is extremely resistant to the above-mentioned complex deterioration.

[Brief explanation of the drawing]

FIG. 1 of the accompanying drawings shows the anti-aging effect by an oxygen absorption test, where the solid line shows the test results before solvent extraction, and the broken line shows the test results after solvent extraction. Also,
Line (A) shows the results for the vulcanizate of Example 9, line (B) shows the results for the vulcanizate of Example 10, and line (C) shows the results for the vulcanizate of Comparative Example 3.

Claims (1)

[Claims] 1 General formula () {In the formula, R ₁ is -NHC ₆ H ₄ NHC ₆ H ₅ , -N(C _n
H _2n+1 ) C ₆ H ₄ NHC ₆ H ₅ (m is an integer from 3 to 8), -
NHC ₆ H _4-p (tert-C ₄ H ₉ ) _p OH (p is an integer from 1 to 2)
and [Formula], R ₂ is R ₁ or -S _x -R ₃ [x is an integer of 1 to 3, R ₃ is -N(C _o H _2o+1 ) ₂ (n is 1 (an integer of ~5) or a group of [Formula]]. } A novel anti-aging agent for rubber comprising a compound in which one or two monothio, dithio or trithio groups are bonded to a 1,3,5-triazine nucleus represented by . 2 General formula () (In the formula, R ₀ represents R ₁ or SH, and R ₁ has the same meaning as described in the above formula ().) A 1,3,5-triazinethiol compound represented by the general formula () R ₃ Cl () or general formula () (R ₃ ) ₂ S _y () [In formulas () and (), R ₃ has the same meaning as described in the above formula (), and y is an integer of 1 or 2. show. monothio, dithio or trithio in the 1,3,5-triazine nucleus represented by the general formula () of claim 1, characterized in that A method for producing a novel anti-aging agent for rubber comprising a compound in which one or two groups are bonded.