JPH0759651B2 - Rubber composition containing antioxidant - Google Patents

Description

The present invention relates to a novel non-extractable rubber composition containing an antioxidant.

[Prior Art] The present inventors have already described the following general formula (4). In the R of the 1,3,5-triazine ring as shown in, for example, —NHC ₆ H
₄ NHC ₆ H ₅ having an antioxidant group introduced thereinto, a compound having X as R (hereinafter abbreviated as 2AD-SH) or a compound having SH is synthesized, and these compounds (4) are converted to butadiene rubber. MBTS (dibenzothiazyl disulfide) crosslinked to an unsaturated rubber having a double bond such as (hereinafter abbreviated as BR), or
When used in combination with MBTS-sulfur crosslinking, it reacts with the rubber to form side chains, which makes it difficult for the compound of general formula (4) bound to the crosslinked rubber to be extracted into the solvent, and this crosslinked rubber undergoes solvent extraction treatment. However, it has been shown that it retains anti-aging properties [Yoshio Nakamura, Kunio Mori, Fumio Akaishi; Journal of Japan Rubber Association]
50 548 (1977)].

[Problems to be Solved by the Invention] However, even when used in combination with the above MBTS crosslink or MBTS-sulfur crosslink, the bonding ratio of the compound of the above formula (4) to the rubber is still low, and therefore the crosslinked rubber is aged. It is hard to say that it is still sufficient in terms of sex.

An object of the present invention is to improve the above-mentioned drawbacks of the prior art and to provide a novel antiaging agent having excellent non-extractability.

[Means for Solving Problems] The inventors of the present invention have made various studies to solve the above problems, and as a result, have generally shown that the triazine ring of the above formula (4) has two antioxidant groups. Formula (1) [Wherein R ¹ is —NHC ₆ H ₄ NHC ₆ H ₅ , or —N (C _m H _{2m + 1} ) C ₆ H ₄
NHC ₆ H ₅ (m is an integer of 3 to 8)] and a general formula (2) having reactivity with p-aminodiphenylamine We have succeeded in synthesizing a new anti-aging agent of [wherein R ² represents> NC ₆ H ₄ NHC ₆ H ₅ ].

And these two kinds of antioxidants are acrylonitrile-butadiene rubber (hereinafter abbreviated as NBR), styrene-butadiene rubber (hereinafter abbreviated as SBR), isoprene rubber (hereinafter abbreviated as IR), natural rubber ( (Hereinafter, abbreviated as NR) and the like, or by blending it with an unsaturated rubber (hereinafter, abbreviated as rubber), or the following formula (3) The present invention has been completed by discovering the fact that the compounding ratio of (1) to (3) is used together for crosslinking and that the rate of bonding to rubber is high, and therefore the aging resistance of the obtained crosslinked rubber is remarkably excellent even after solvent extraction.

The present invention has been completed based on the above findings, that is, the compound represented by the general formula (1) and / or (2) is contained in an amount of 0.5 to 10 parts by weight based on 100 parts by weight of rubber. A rubber composition containing an antioxidant and 0.5 to 10 parts by weight of an antioxidant represented by the general formula (1) and / or (2) per 100 parts by weight of rubber, and a compound represented by the formula (3) 0.3 to 100 parts by weight of rubber
The present invention newly provides a rubber composition containing an antioxidant characterized by containing 15 parts by weight.

In the present invention, the antioxidant represented by the general formula (1) can be synthesized, for example, as follows. That is, when cyanuric chloride is first reacted with diallylamine in an organic solvent and then 4-aminodiphenylamine is added and reacted, 2-diallylamino-4,6-bis- (N'-
Phenyl-p-phenylenediamino) -1,3,5-triazine [2AD-AA] is obtained. The chemical reaction formula is as follows.

The antioxidant represented by the general formula (2) (hereinafter abbreviated as DA) is produced by reacting 4-aminodiphenylamine with allyl chloride in an organic solvent, then adding water to the reaction solution, and then adding ether. The product is extracted with ether to obtain N, N-diallyl-N'-phenyl-p-phenylenediamine [DA]. The chemical reaction formula is as follows.

Then, specific examples of the anti-aging agent for rubber represented by the general formula (1) include, for example, 2-diallylamino-4,6.
-Bis- (N'-phenyl-p-phenylenediamino)
-1,3,5-triazine [2AD-AA], 2-diallylamino-4,6-bis- (N'-phenyl-N-isopropyl-
p-phenylenediamino) -1,3,5-triazine and the like are exemplified, and the antioxidant represented by the general formula (2) is
N, N-diallyl-N'-phenyl-p-phenylenediamine [DA]. Further, examples of the compound represented by the formula (3) include 1,3,5-triazine-2,4,6-trithiol [hereinafter abbreviated as TTCA].

The addition amount of the antioxidant of the general formula (1) and / or (2) and the compound of the formula (3) to the rubber varies depending on the kind of the rubber product and the properties required for the rubber product, but generally it is the weight. The amount of the antioxidant of the general formula (1) and / or (2) is 0.5 to 10 parts per 100 parts of rubber. The compound of formula (3) is also 0.3 to 15 parts, preferably 0.5 to 5 parts.
It is a department.

In addition, depending on the purpose, vulcanizing agents such as sulfur, MBT
One or more vulcanization accelerators such as S, CBS (cyclohexylbenzothiazole sulfenamide), TMTM (tetramethylthiuram monosulfide), DPG (diphenylguanidine) and H (hexamethylenetetramine) can be used in combination. In addition, it is possible to add carbon black, silica, an inorganic filler, other antiaging agents, etc. which are commonly used in rubber compounding.

The anti-aging agent-containing rubber composition of the present invention can be mixed and crosslinked by an ordinary method, but in order to fully exert the effects of the present invention, the compounds of the general formula (1) and / or (2) are used. It is better to combine the anti-aging agent or the compound of formula (3) with the anti-aging agent, and mix them in advance by heating (for example, at 160 ° C. for 20 minutes) and then kneading into the rubber to improve the binding rate of the anti-aging agent to the rubber. Is preferred, which is preferable.

EXAMPLES Next, examples of the present invention will be described more specifically.
Of course, the present invention is not limited to the above description.

1. Rubber sample 1-1. Mixing and kneading NBR (JIR-N230S, AN: 35%) 100 parts, ZnO 4 parts, stearic acid (St) 1 part, anti-aging agent (2AD-AA, DA), vulcanization The accelerators (MBTS, CBS, DS, TMTM) and the amounts of sulfur and TTCA were changed, and the mixture was roll-kneaded for 10 minutes to prepare an NBR compound.
Further, when the antioxidant, vulcanization accelerator, sulfur and TTCA are preliminarily reacted and roll kneading is performed, these reagents are mixed well in a mortar, and after reacting at 160 ° C for 20 minutes, the reaction product is well mixed in a mortar. The crushed roll was kneaded to obtain an NBR compound.

1-2. Quantification of antioxidant group bound to NBR rubber ¹⁾ NBR film for IR spectrum measurement used for quantification of antioxidant group is NBR
A vulcanized rubber film (thickness 2μ) was azeotroped with methanol-acetone-chloroform (volume ratio = 28:35:29).
Soxhlet extraction was performed for 48 hours to extract unreacted antioxidant. The content of antioxidant groups bound to the rubber is 16% of this sample.
The ratio of the absorbance at 50 cm ^-1 (νC _{= C of} unsaturated bond of NBR) and 1600 cm ^-1 (ν _{C = C} of benzene nucleus of antioxidant group) was measured and determined from the calibration curve of FIG. The calibration curve is 2AD-AA, DA
Was made from the blended film of NBR and NBR as a model of the structure of the antioxidant group bound to NBR.

Note ¹⁾ Journal of Japan Rubber Association 43 337 to 345 (1970) 1-3. Heat aging test and physical test (a) For the heat aging test, NBR compound obtained by roll-kneading NBR and various compounding agents for 10 minutes Was heated at 160 ° C. for 20 minutes, and a 2 mm thick NBR vulcanizate was molded into a JIS3 type dumbbell and used.

(B) After extraction, the sample obtained above was extracted with a Soxhlet extractor for 48 hours using a methanol-acetone-chloroform (volume mixing ratio 28:35:29) azeotrope mixed solvent.
It was obtained by vacuum drying at ℃ for 24 hours.

(C) The heat aging test of the vulcanizate was conducted in a gear oven at 120 ° C, and the strength and elongation of the sample before and after aging (pulling speed of 200 mm / min at 25 ° C) were measured using Shimadzu Auto Club S100. The retention rate after aging was obtained to evaluate the degree of aging.

Examples 1 to 5 Table 1 shows the anti-aging agent binding rate (%) of Examples 3 to 5 [hereinafter,
Abbreviated as a protective bond ratio (%)] is higher than in Comparative Examples 1 and 2. In addition, Examples 1 to 2 and Examples 3 to 5
In comparison, it is shown that the combined use of TTCA improves the protective bond rate (%).

Examples 6 to 7 Table 2 shows that Examples 6 to 7 are superior to Comparative Example 3 in physical properties (T _B , E _B ) in a heat aging test at 120 ° C. and physical properties after extraction with an azeotropic solvent mixture. Is shown.

Examples 8 to 11 Table 3 shows the compound (3) TTCA and the antioxidant of the present invention (1).
It shows a comparison of the anti-bonding ratio (%) when (2AD-AA) and / or (2) (DA) were heated and reacted at 120 ° C. for 20 minutes and kneaded into rubber. That is, in Examples 8 to 11 in which the compounding agent was heat-treated, the protective bond ratio (%) was remarkably improved as compared with the case where the compounding agent was not heat-treated.

These examples suggest that the rubber composition containing the antiaging agent 2AD-AA and / or DA of the present invention and the compound (3) TTCA gives a vulcanized rubber excellent in heat aging resistance. .

[Advantages of the Invention] The anti-aging agent of the present invention has a high binding rate to rubber,
The obtained crosslinked rubber has an extremely excellent aging resistance and an extremely good durability, and in particular, can provide a non-extractable antiaging effect.

[Brief description of drawings]

 FIG. 1 shows the calibration curve of the reactive anti-aging agent.

Claims (2)

[Claims] 1. The following general formula (1) and / or general formula (2) [Wherein R ¹ is —NHC ₆ H ₄ NHC ₆ H ₅ , or —N (C _m H _{2m + 1} ) C ₆ H ₄
NHC ₆ H ₅ (m is an integer of 3 to 8)] [Wherein R ² represents> NC ₆ H ₄ NHC ₆ H ₅ ] is added in an amount of 0.5-10 with respect to 100 parts by weight of rubber.
An antiaging agent-containing rubber composition, characterized in that it is contained in an amount of 1 part by weight. 2. The following general formula (1) and / or general formula (2) [Wherein R ¹ is —NHC ₆ H ₄ NHC ₆ H ₅ , or —N (C _m H _{2m + 1} ) C ₆ H ₄
NHC ₆ H ₅ (m is an integer of 3 to 8)] [Wherein R ² represents> NC ₆ H ₄ NHC ₆ H ₅ ] is added in an amount of 0.5-10 with respect to 100 parts by weight of rubber.
Parts by weight, and the following formula (3) A rubber composition containing an antioxidant, characterized in that the compound represented by (3) is contained in an amount of 0.3 to 15 parts by weight per 100 parts by weight of rubber.