JPH07149990A - Synthetic rubber composition - Google Patents

Abstract

PURPOSE:To provide a synthetic rubber compsn. mainly usable in a lubricating oil hose, a fuel hose, etc., for a car and excellent in cold resistance and heat resistance by using an acrylic rubber or a hydrogenated nitrile rubber as the main component. CONSTITUTION:A synthetic rubber compsn, comprises at least one synthetic rubber selected from among acrylic rubbers and hydrogenated nitrile rubbers, and at least one dibasic fatty diester of alkoxypolyethylene glycol added thereto and represented by the formula (wherein R and R' are each a 8-18C alkyl group; R''-is a 1-12C alkylene group; and n is 2 to 5).

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a synthetic rubber composition having excellent cold resistance and heat resistance, and more specifically, it is mainly used for lubricating oil hoses and fuel hoses for automobiles, and is made of acrylic rubber and hydrogenated nitrile rubber. The present invention relates to a synthetic rubber composition excellent in cold resistance and heat resistance, which is obtained by adding at least one dibasic fatty acid diester of alkoxy polyethylene glycol to at least one selected synthetic rubber.

[0002]

2. Description of the Related Art Among synthetic rubbers, acrylic rubber and hydrogenated nitrile rubber are
Because of its excellent heat resistance and oil resistance, it is mainly used for lubricating oil hoses and fuel hoses for automobiles. The rubber material used for such an application needs to have flexibility, and in order to withstand use especially in cold regions, it is required to have good cold resistance, that is, to retain flexibility even at low temperatures. R. Also, due to the increase in engine output due to the recent innovation of automobile technology, the use environment has become higher in temperature, and rubber materials used for such applications have high heat resistance, that is,
It is also necessary to maintain the initial physical properties even when exposed to high temperatures.

Conventionally, ester-based plasticizers have been blended in rubber materials used for such applications in order to impart cold resistance. However, the conventionally used ester-based plasticizers have comparative cold resistance. However, the heat resistance is poor, and the physical properties after heating are significantly deteriorated.

For example, JP-A-59-122532 proposes to use an ester of a hydroxy compound and an unsaturated fatty acid as a cold resistance improver for rubber, and JP-A-61-145236. It has been proposed to add a reaction product of an alkylene glycol or polyoxyalkylene glycol and a fatty acid, a dicarboxylic acid or a polymer acid to a chloroprene rubber.
JP-A-2-253643 proposes to add a reaction product of an alkylene glycol or polyoxyalkylene glycol and a fatty acid, a dicarboxylic acid or a polymer acid to a butadiene rubber.

An ester compound of an alkoxypolyalkylene glycol and a dibasic acid is known as a plasticizer for synthetic rubber. For example, Japanese Patent Laid-Open No. 53-10645 discloses propoxytriethylene glycol or butoxydiethylene glycol and a diacid. It is described that an ester compound with a basic acid is effective as a cold-resistant plasticizer for synthetic rubber,
EPA 0439443 discloses that an ester compound of an alkoxypolyalkylene glycol and a dibasic acid improves weather resistance and processability of a rubber-modified graft copolymer. Synthetic rubber compositions used as plasticizers for rubber or hydrogenated nitrile rubber have not yet been sufficiently satisfactory in cold resistance and heat resistance.

Therefore, an object of the present invention is to mainly use in a lubricating oil hose or a fuel hose for automobiles, and a synthetic rubber composition containing acrylic rubber or hydrogenated nitrile rubber as a main component and having excellent cold resistance and heat resistance. To provide things.

[0007]

As a result of various investigations, the present inventors have found that at least one kind of synthetic rubber selected from acrylic rubber and hydrogenated nitrile rubber is used as a dibasic fatty acid of a specific alkoxy polyethylene glycol. The present invention has been completed by finding that a synthetic rubber composition obtained by adding at least one kind of diester can achieve the above object.

That is, the present invention is represented by the general formula (I) of the following [Chemical formula 2] (the same as the above [Chemical formula 1]) in at least one kind of synthetic rubber selected from acrylic rubber and hydrogenated nitrile rubber. The present invention provides a synthetic rubber composition having excellent cold resistance and heat resistance, which is obtained by adding at least one dibasic fatty acid diester of alkoxy polyethylene glycol.

[0009]

[Chemical 2]

The synthetic rubber composition of the present invention will be described in detail below.

The acrylic rubber used in the present invention is a polymer or copolymer of at least one monomer selected from the group consisting of alkyl acrylates such as ethyl acrylate and butyl acrylate. It may be a copolymer with a monomer such as methoxyethyl acrylate, ethoxyethyl acrylate, acrylonitrile, 2-chloroethyl vinyl ether, vinyl monochloroacetate, allyl chloroacetate, allyl glycidyl ether, glycidyl methacrylate and ethylene.

The hydrogenated nitrile rubber used in the present invention is obtained by hydrogenating a part or all of the unsaturated bonds of the main chain in order to improve the heat resistance of the nitrile rubber. JP-A-52-32095, JP-A-59-115303, JP-A-59-1175.
Various production methods are disclosed in Japanese Patent Publication No. 01, etc., but are not particularly limited. Further, the nitrile rubber is a copolymer of acrylonitrile and butadiene,
It may be a copolymer of the copolymer and a third component such as divinylbenzene, methacrylic acid or acrylic acid.

In the above general formula (I), the alkyl group having 8 to 18 carbon atoms represented by R and R'includes octyl, 2-ethylhexyl, isooctyl, nonyl, isononyl, decyl, isodecyl, undecyl, isoundecyl. , Dodecyl, isododecyl, tridecyl, isotridecyl, tetradecyl, isotetradecyl, pentadecyl, isopentadecyl, hexadecyl, isohexadecyl, heptadecyl, isoheptadecyl, octadecyl,
Examples thereof include groups such as isooctadecyl, and among these, an alkyl group having 8 to 12 carbon atoms is more preferable. Here, if the number of carbon atoms is less than 8, heat resistance and cold resistance cannot be obtained, and if the number of carbon atoms exceeds 18, the compatibility with acrylic rubber or hydrogenated nitrile rubber is poor.
Examples of the alkylene group having 1 to 12 carbon atoms represented by R ″ include groups such as methylene, ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene and dodecylene. However, an alkylene group having 4 to 10 carbon atoms is more preferable, where one having more than 12 carbon atoms has poor compatibility with an acrylic rubber or a hydrogenated nitrile rubber, and n is 2 to 5, particularly 2 or When n is less than 2, satisfactory heat resistance cannot be obtained, and when n exceeds 5, compatibility with acrylic rubber or hydrogenated nitrile rubber is poor and cold resistance is satisfactory. I can't.

Accordingly, examples of the compound represented by the above general formula (I) used in the present invention include compounds 1 to 6 of the following [formula 3] to [formula 8].

[0015]

[Chemical 3]

[0016]

[Chemical 4]

[0017]

[Chemical 5]

[0018]

[Chemical 6]

[0019]

[Chemical 7]

[0020]

[Chemical 8]

The compound represented by the general formula (I), that is, the dibasic fatty acid diester of alkoxypolyethylene glycol can be easily produced by the esterification reaction of the alkoxypolyethylene glycol and the dibasic fatty acid. The manufacturing method is not particularly limited.

The amount of the compound represented by the general formula (I) added varies depending on the use, but is usually 2 to 50 parts by weight, preferably 5 to 30 parts by weight, based on 100 parts by weight of the rubber component. .

To obtain the synthetic rubber composition of the present invention,
A usual rubber kneading method can be applied, and for example, an open roll, a Banbury mixer, a kneader blender or the like is used depending on the purpose.

If necessary, the synthetic rubber composition of the present invention contains additives such as vulcanizing agents, vulcanization accelerators, antioxidants, fillers, softening agents and processing aids. Agents and the like can be added.

[0025]

EXAMPLES Hereinafter, the composition of the present invention and its effect will be specifically described with reference to examples. However, the invention is not limited to these examples.

Example 1 In order to confirm the compatibility of various ester compounds with acrylic rubber and hydrogenated nitrile rubber, Banbury kneading was carried out by the following formulations [formulation 1], [formulation 2] and [formulation 3]. Then, the exudation phenomenon from the sheet obtained by press molding was observed. The results are shown in [Table 1] below.
Shown in. The pressing conditions differ depending on the composition and are shown in the following [Table 1]. In addition, the evaluation criteria for bleeding are as follows.

[Evaluation Criteria] ○: No bleeding out △: Some bleeding out ×: Severe bleeding out

[Formulation 1] Parts by weight AR-31 (acrylic rubber manufactured by Zeon Corporation) 100 FEF carbon 50 stearic acid 1 ammonium benzoate 1 test compound (shown in [Table 1] and [Table 2] below) 15

[Formulation 2] Parts by weight Baymac G (ethylene acrylic rubber manufactured by DuPont) 100 MAF carbon 50 stearic acid 2 stearylamine 0.5 hexamethylenediamine 1.25 Noward 445 (manufactured by Uniroyal Antiaging Agent) 2 test compound ( (Shown in [Table 1] and [Table 3] below) 20

[Compound 3] Parts by weight Zettopol 2010 100 (hydrogenated nitrile rubber manufactured by Nippon Zeon) FEF carbon 55 Peroximon F-40 (peroxide manufactured by NOF Corporation) 6 test compounds ([Table 1] and [Table 4 below] ]) 20

[0031]

[Table 1]

Comparison-1 to comparison-4 in the above [Table 1]
Are compounds of the following [Chemical Formula 9] to [Chemical Formula 12], respectively.

[0033]

[Chemical 9]

[0034]

[Chemical 10]

[0035]

[Chemical 11]

[0036]

[Chemical 12]

Examples 2 to 4 According to the formulations of [formulation 1], [formulation 2] and [formulation 3] of Example 1, hardness was measured and tensile strength and elongation were measured by a tensile test. In addition, the hardness, tensile strength and elongation after heat aging (175 ° C. × 70 hr) were measured, and the difference in hardness was determined. Further, for the formulations of [Compound 1] and [Compound 2], the embrittlement temperature before and after heat aging was measured, and for the formulation of [Composition 3], the low temperature twist temperature before and after heat aging was measured. The above test was conducted according to JIS K-6301.

Further, the weight reduction of the plasticizer at the time of secondary vulcanization was measured by the formulations of [formulation 1] and [formulation 2] of Example 1. The evaluation method is 15 using a sheet with a thickness of 2 mm.
A 0 mm × 150 mm test piece was prepared and calculated from the mass change when placed in a gear oven at 175 ° C. for 4 hours and 2 hours, respectively.

[Formulation 1], [Formulation 2] and [Formulation 3]
The evaluation results of the prescription of
It shows in [Table 3] and [Table 4]. The vulcanization conditions are shown below the table.

[0040]

[Table 2]

[0041]

[Table 3]

[0042]

[Table 4]

From the results of [Table 2] to [Table 4] above, among the dibasic fatty acid esters of alkoxyalkylene glycol, those having a larger alkyl group or ethylene oxide unit than those of the present invention, Inferior compatibility with acrylic rubber or hydrogenated nitrile rubber, short alkyl groups or small ethylene oxide units have excellent compatibility but cannot provide sufficient performance for cold resistance and heat resistance. I understand.

On the other hand, the dibasic fatty acid ester of the alkoxyalkylene glycol of the present invention represented by the above general formula (I) has excellent compatibility with acrylic rubber or hydrogenated nitrile rubber, and further has cold resistance and heat resistance. It can be seen that the sexual performance is excellent.

[0045]

The synthetic rubber composition of the present invention is obtained by adding at least one dibasic fatty acid diester of a specific alkoxy polyethylene glycol to at least one synthetic rubber selected from acrylic rubber and hydrogenated nitrile rubber. It has excellent cold resistance and heat resistance, and is mainly used for lubricating oil hoses and fuel hoses for automobiles.

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[Procedure amendment]

[Submission date] March 15, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0024

[Correction method] Change

[Correction content]

If necessary, the synthetic rubber composition of the present invention contains additives such as vulcanizing agents, vulcanization accelerators, antioxidants, fillers, softening agents and processing aids. Agents and the like can be added. The synthetic rubber composition of the present invention,
Lubrication due to excellent cold resistance and heat resistance
Oil hose, fuel hose, diaphragm, packing, tie
Suitable for automotive applications such as ming belts
However, as a matter of course, its application is limited to automobile applications.
Not specified, but an oil seal, gasket, seal
Other uses such as printing rolls, blankets, and steelmaking rolls
It can also be used en route .

Claims (1)

[Claims] 1. At least one synthetic rubber selected from acrylic rubber and hydrogenated nitrile rubber, and at least one dibasic fatty acid diester of alkoxypolyethylene glycol represented by the following general formula (I) A synthetic rubber composition which is excellent in cold resistance and heat resistance. [Chemical 1]