JPS595211B2 - stabilized rubber composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to rubber compositions stabilized by novel stabilizers.

In order to prevent deterioration of polymeric substances due to the effects of heat, light, oxygen, ozone, etc., phenol-based and amine-based deterioration inhibitors have been widely used.

By the way, the present inventors have developed a deterioration inhibitor that is superior to the above-mentioned known deterioration inhibitors for rubbers in which the compound represented by the following general formula contains a carbon-carbon double bond in the main chain. The present invention was completed based on the new finding that it has an effect. In the present invention, the stabilizer 10 used as a stabilizer has the following general formula; is an alkyl group or an aryl group, X is a hydrogen atom, hydroxy group, amino group, or alkyl group, Y is a hydrogen atom, hydroxy group, alkoxy group, amino group, or an alkyl group, and At least one of Y is always the above atomic group other than a hydrogen atom.

] Monocyclic aromatic amides. Among the above monocyclic aromatic amides, preferred are those represented by the general formula:
is an amino group, especially a monoalf5 kylamino group or a dialkylamino group. Furthermore, in the monocyclic aromatic amide, the 2nd and 4th positions of the aromatic ring are substituted with a hydroxyl group, an amino group, or an alkyl group, or in the above general formula, either R1 or R2? When 0 is an aryl group and the aryl group has an amide group, an alkoxy group or a substituted amino group, in particular, all the amide groups contained in the monocyclic aromatic amides are When it is a secondary or tertiary amino group, it is suitably used as a particularly preferred stabilizer in the present application. Representative examples of these particularly preferred stabilizers are shown below. Each of the above stabilizers can be easily produced by conventionally known methods. For example, the stabilizer may be 1 mole of P-nitroaniline and 1 mole of P-nitrobenzoic acid.
mol in toluene in the presence of phosphorus trichloride at 120°C,
After reacting for 4 hours, it was made alkaline with Na2cO3, and the 4,4'-dinitro compound precipitated by leaking toluene was heated to 80°C in iron monohydrochloric acid, reduced, and dissolved in soda ash. The stabilizer (P-dimethylamino(P-dimethylaminobenzoic acid) anilide) is obtained by neutralizing the above stabilizer with methyl iodide. Obtained by methylation depending on Other stabilizers of the present invention can be easily produced in substantially the same manner by dehydration condensation reaction of the corresponding carboxylic acid and amino compound. Each of the stabilizers thus obtained is preferably a purified product, but there is no need for further purification, and even industrial grade products can sufficiently exhibit the desired performance.

The above-mentioned stabilizers used in the present invention are ASTM
R class in the rubber nomenclature according to D-1418-72a, that is, rubbers with unsaturated carbon bonds in the main chain, can be used alone or as a mixture of two or more, or with conventional rubber compounding agents and fillers. It is used in combination with a known stabilizer and kneaded using conventional mixing methods and equipment such as a roll mill, Banbury mixer, or rubber extruder, and prevents discoloration due to oxidation of the resin base material during heating and processing. To effectively prevent deterioration of an obtained molded product without causing deterioration or deterioration. Above AS
R-class rubbers according to TM include natural rubber and various synthetic rubbers, examples of the latter include butadiene rubber (BR), brominated butyl rubber (BIIR), chlorinated butyl rubber (CIIR), butyl rubber (IIR), and chloroprene. rubber (CR), isoprene rubber (IR), nitrile rubber (NBR), and styrene-butadiene rubber (S
BR) is available.

In addition to the above-mentioned rubbers, the stabilizer used in the present invention is also effective when applied to chlorosulfonated polyethylene, epichlorohydrin rubber, fluorine rubber, silicone rubber, and the like.

Furthermore, the stabilizer does not color or discolor the resin base material, does not leach from the rubber base material during processing and molding, and even during use, thus stabilizing the rubber base material over a long period of time. At the point. Furthermore, the stabilizing effect of the stabilizer of the present invention remains unchanged even when the rubber base material is crosslinked.

The amount of stabilizer used is determined depending on the rubber base material used, the type of additives and fillers used together, and the purpose of the molded/processed product, but it is usually 100 parts by weight (parts by weight) of the resin base material. , hereinafter the same), in an amount of 0.1 to 10 parts, more preferably 0.2 to 5 parts. Therefore, the present invention is useful as a highly stable rubber composition for general molding industrial products or electrical insulation.

Next, the remarkable effects of the composition of the present invention will be explained with reference to Examples and Comparative Examples; however, the present invention is not limited to these Examples in any way.

Examples 1 to 6, Comparative Example 1 Solution polymerized SBR (manufactured by Asahi Kasei, Tuffden 2000, amount of bound styrene 25%, specific gravity 0.93
) was used as a resin base material, and one or two of the stabilizers exemplified by the above structural formula were blended in the following basic formulation to obtain compositions of Examples.

This composition was kneaded using rolls, and then press vulcanized at 150°C for 20 minutes. It was made into a thick sheet.

This sheet was punched out using a JIS No. 3 tamper to obtain sample pieces. Note that a sample piece not containing the stabilizer of the present invention was also prepared as Comparison 1 in the same manner.

The prepared sample piece was placed in a gear oven at 1200C.
After deteriorating for a predetermined period of time, its tensile strength (Kg/Mm
2) and elongation (%) were measured, and the aging resistance was evaluated based on the ratio (remaining rate, %) to each measured value before aging.

The results are shown in Table 1〇As is clear from Table 1,
The composition of the present invention has extremely excellent stability compared to the composition without additives (Comparative Example 1). Example 7
~12, Comparative Example 2 IIR (manufactured by Polysar Co., Ltd., butyl #100) was used as the resin base material.
, unsaturation degree 0.7%), and one or two of the stabilizers exemplified by the above structural formula were blended in the following basic formulation to obtain compositions of examples.

This composition was kneaded using rolls, and then press vulcanized at 160'C for 45 minutes to form a sheet with a thickness of 2m7n.

Sample pieces were prepared from this sheet in the same manner as in Examples 1 to 6, and the same deterioration test was conducted to obtain the results shown in Table 2. Incidentally, a test on a composition (Comparative Example 2) not containing the stabilizer of the present invention was conducted in the same manner. As is clear from Table 2, the composition of the present invention has no additives (Comparative Example 2).
It has extremely superior stability compared to the case of

Examples 13 to 18, Comparative Example 3 Using NBR (Hiker 1042 manufactured by B.F. GOOdrlch, 30% nitrile) as the resin base material, in the following basic formulation, one of the stabilizers exemplified by the above structural formula was used. ~
The two types were blended to form a composition of an example.

This composition was kneaded using a roll, and then press vulcanized at 160°C for 45 minutes to form a 2 mm thick sheet.
Sample pieces were prepared from this sheet in the same manner as in Examples 1 to 6, and the same deterioration test was conducted to obtain the results shown in Table 3.

The same procedure was carried out for Comparative Example 3 which did not contain the stabilizer of the present invention. Table 3 also shows that the composition of the present invention has extremely superior stability compared to the composition without additives (Comparative Example 3). Examples 19 to 24, Comparative Example 4 Vulcanized sample pieces were collected in the same manner as Examples 1 to 6, except that chloroprene (Neoprene W, manufactured by Showa Neoprene Co., Ltd.) was used as the resin base material, and the following basic formulation was used. A deterioration test was conducted under the same conditions for Examples 19 to 24 and Comparative Example 4 in which the stabilizer of the present invention was not added, and the results shown in Table 4 were obtained.

Claims (1)

[Claims] 1. A rubber containing a carbon-carbon double bond in the main chain has the general formula ▲
There are mathematical formulas, chemical formulas, tables, etc. ▼ [In the formula, R^1 and R^2 are a hydrogen atom, an alkyl group, a hydroxyalkyl group, an aminoalkyl group, or an aryl group, and X is a hydrogen atom, a hydroxyl group, or an amino group. or an alkyl group, Y is a hydrogen atom, a hydroxy group, an alkoxy group, an amino group, or an alkyl group, and at least one of X or Y is always the above atomic group other than a hydrogen atom. ] A stabilized rubber composition comprising a monocyclic aromatic amide represented by the following as a stabilizer.