JPH09324083A - Rubber composition and method for inhibiting coloration by staining - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a sulfur-vulcanizable rubber compsn. which does not stain a coated metal sheet in contact therewith by componding an ethylene-propylene- diene terpolymer, an acid anhydride, sulfur, and a specific vulcanization accelerator as the main ingredients. SOLUTION: This compsn. mainly comprises 100 pts.wt. ethylene-propylene- diene terpolymer, at least one acid anhydride pref. in an amt. of 0.1-5 pts.wt. and pref. selected from among phthalic, trimellitic, pyromellitic, benzophenonetetracarboxylic, and citraconic anhydrides, sulfur, and at least one vulcanization accelerator which is not prepared from an amine having a b.p. under normal pressure of 100 deg.C or lower and is selected from among N,N'-diphenylguanidine, dibenzothiazyl disulfide, a zinc salt of 2- mercaptobenzothiazole, N-cyclohexylbenzothiazyl-2-sulfenamide, and zinc dibutyldithiocarbamate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composition of ethylene-propylene-diene monomer copolymer (hereinafter referred to as "EPDM") which does not contaminate contacting automobile painted sheet metal and the like and its use. is there. EPDM is a mixture of ethylene and propylene with a small amount of a diene monomer and copolymerization. Examples of the diene monomer include ethylidene norbornene, 1,4-hexadiene, dicyclopentadiene and the like.

[0002]

2. Description of the Related Art Rubber products vulcanized and molded using an EPDM compounding composition are excellent in ozone resistance, heat resistance and the like. Therefore, cushion rubber for automobiles, weather strips and the like which require these characteristics are required. It is widely used as a material. The vulcanization method includes sulfur vulcanization type and non-sulfur vulcanization type (organic peroxide vulcanization type). Among them, the non-sulfur vulcanization type has less yellowing phenomenon of the coated sheet metal in contact, but the cost, productivity and physical properties are significantly inferior to the sulfur vulcanization type, so high productivity and low cost etc. From the standpoint of, sulfur vulcanization systems are usually used.

[0003]

[Problems to be Solved] However, sulfur vulcanization type EPD
As described above, when a rubber product molded from the M composition is left in contact with an automobile coating plate or the like, the contact surface yellows, resulting in a problem that the appearance function is significantly impaired.

[0004]

The present invention relates to a vulcanization which does not use an amine as a raw material and has a boiling point of 100 ° C. or less at atmospheric pressure (hereinafter, in the description of the boiling point of amine, description that atmospheric pressure is omitted). By using an accelerator and an acid anhydride together, it was found that the above-mentioned problems were solved even though it was a sulfur vulcanization system, and color contamination when contacting with the mating material was suppressed, and to complete this I arrived. That is, an object of the present invention is to provide a rubber composition which is excellent in preventing coloring of a coated metal plate.

It is considered that the stain on the coated plate discussed in the above-mentioned problems is caused by the kind of the vulcanization accelerator used, and the amine as a raw material has a stain of 100 ° C. as a boundary. It can be divided into certain vulcanization accelerators and weakly polluting agents. However, even when a vulcanization accelerator not having an amine having a boiling point of 100 ° C. or lower as a raw material was used in combination, there was still a slight dry stain on the coated metal plate. However, by adding an acid anhydride such as phthalic anhydride or pyromellitic dianhydride to this system, contamination and coloring can be completely prevented. Even when an acid anhydride was used in combination with a vulcanization accelerator whose raw material was an amine at 100 ° C. or lower, the effect was not obtained.

The rubber composition of the present invention, which is excellent in coloration-preventing property due to contact with the mating material, contains EPDM, acid anhydride, and sulfur, and when the EPDM is 100 parts by weight, the acid anhydride is 0.1% by weight. It is 1 to 5 parts by weight, and more preferably 1 to 2 parts by weight. The types of acid anhydrides used in the present invention include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic anhydride, citraconic anhydride,
Itaconic anhydride, Tetrahydrophthalic anhydride, Tetrahydromethylphthalic anhydride, Ethylene glycol bis-anhydro trimellitate, Glycerol tris-anhydro trimellitate, Nadic acid anhydride, Methyl nadic acid anhydride, Ethylene-styrene- Examples thereof include maleic anhydride copolymer resin and isobutylene-maleic anhydride copolymer resin.

Examples of amines used as raw materials for vulcanization accelerators, their boiling points, and vulcanization accelerators are shown below. Vulcanization accelerator Raw material amine Boiling point (° C) Tetramethylthiuram disulfide dimethylamine 6.9 Tetramethylthiuram monosulfite dimethylamine 6.9 Dimethyldithiocarbamic acid zinc dimethylamine 6.9 N-N'-diethylthiourea ethylamine 16.6 N-tert-butyl benzylsodium thiol- 2-tert-Butylamine 45.0 Sulfenamidodiethyldithiocarbamate Zinc diethylamine 55.5 Diethyldithiocarbamate tellurium diethylamine 55.5 Tetraethylthiuram disulfopyridine Diamine 55.5 N-N'-Dihexylpyrupyrpyrupyridine pyrulydine pyrethridine pyrethlidine 10% 106.0 Ethylenethiourea Ethylenediamine 116 .5 N-Oxyethylene Ethylene Benzothiazyl-2-Morpholine 129.0 Sulfenamid 2-Mercapto Benzothiazol Cyclohexylamine 134.0 Cyclohexylamine Salt N-Cyclohexylbenzenthiazyl-2-Cyclohexylamine 134.0 Sulfenamido N-Methyl 13% N'-Methylphenylazinosulfenamidyl dibutylaminedithiocarbamate dibutylamine 159.0 -Le aniline 184.0 Genzo-thiazyl sulfide aniline 184.0 2-mercapto benzine-zinc salt of aniline aniline 184.0 N, N ' -Di-o-tolylanidin o-toluidine 199.7 Ethylphenyl zinc dithiocarbamate N-ethylaniline 204.7 2-Dicyclohexylamine 254.5 2-mercaptobenzenthiazoyl N, N-Dicyclohexylbenzazothiadicyclohexylamine 254.5 Syl-2- Sulfenamide Tetraoctylthiuram Sulfide Di-2-ethylhexylamine 281.0

From the above examples, the vulcanization accelerator applicable to the present invention without using an amine having a boiling point of 100 ° C. or lower as a raw material is
N, N'-diphenylguanidine, N, N'-di-o-tolylguanidine, 2-mercaptobenzothiazole, dibenzothiazyl disulfide, zinc salt of 2-mercaptobenzothiazole, 2-mercaptobenzothiazo- Cyclohexylamine salt, 2-mercaptobenzothiazole dicyclohexylamine salt, N-cyclohexylbenzothiazyl-2-sulfenamide, N-oxydiethylene benzothiazyl-2-sulfenamide, N, N-
Dicyclohexyl benzothiazyl-2-sulfenamide, ethylenethiourea, tetrabutyl thiuram disulfide, dipentamethylene thiuram tetrasulfide, dipentamethylene thiuram hexasulfide, N-methyl piperazino thiocarbamyl-N'-methyl piperazinosulfenamide , Zinc dibutyldithiocarbamate, zinc ethylphenyldithiocarbamate, tetraoctylthiuram disulfide and the like.

The above-mentioned vulcanization accelerators can be used in combination, and, as a natural consequence, vulcanization accelerators not containing amine as a raw material are also included in the scope of the present invention, and should be added and used together. You can Examples thereof include zinc isopropyl xanthate, zinc dibutyl phosphorodithioate salt and the like. Further, in view of the gist of the invention, a process oil, a carbon black, an anti-aging agent or the like which has no or little pollution can be appropriately used in the rubber composition of the present invention.

[0010]

When a vulcanization accelerator made from an amine having a boiling point of 100 ° C. or lower is used in the vulcanization of EPDM, the amine decomposed and liberated during the vulcanization reaction migrates in the rubber even after being commercialized, It can be presumed that it appears on the rubber surface and significantly contaminates the painted plate with which it comes into contact. On the other hand, when a vulcanization accelerator having an amine having a boiling point of 100 ° C. or lower as a raw material is used, it is presumed that the contamination is considerably reduced because the migration to the rubber surface is slow. In addition, as a result of the above, in the vulcanization accelerator composed of a plurality of amines, the amine having the lowest boiling point should be evaluated as 100 ° C. or below according to the present invention.

The effect can be remarkably improved by further adding an acid anhydride to this system. As shown in Formula 1, the effect of adding an acid anhydride is to prevent migration of amine in rubber by amidating and trapping amine generated from a vulcanization accelerator during vulcanization reaction. Is estimated.

[0012]

(Equation 1)

[0013]

The present invention will be described in detail below with reference to examples and comparative examples. In order to examine the stain resistance of each vulcanization accelerator to the coated sheet metal, a rubber composition containing EPDM, sulfur and a vulcanization accelerator was prepared.

Comparative Example A comparative test of contamination was conducted as shown below. The dough of the following composition contains 8 parts of sulfur, vulcanization accelerator and other compounding agents.
It was obtained by kneading using an inch open roll. This kneaded material was press-vulcanized at 170 ° C. for 20 minutes to obtain a rubber sheet having a thickness of 2 mm. This was cut into a size of 2 cm × 2 cm to prepare each test piece. In addition, as a test method for promoting contamination,
50 g / cm of the created test piece was pinched by an iron plate sprayed with an automotive synthetic resin paint (Super White 2).
A load of ² was applied, and heat treatment was performed in a gear oven at 100 ° C. for 4 hours. The results are summarized in Tables 1-3.

Compounding (parts by weight) EPDM 100 HAF carbon black 90 Process oil 90 Zinc white # 1 5 Stearic acid 1 Sulfur 1 Vulcanization accelerator Other notes Acid anhydrides Other notes

Description of Abbreviations Contamination Test ○: No Contamination △: Slightly Contamination ×: Contamination Compounded Vulcanization Accelerator A: Zinc Isopropylxanthate B: Dibutylphosphorodithioate Zinc Salt C: N-Methyl Piperazinothiocarbamyl-N'-methyl piperazinosulfenamide

[0017]

[Table 1]

[0018]

[Table 2]

[0019]

[Table 3]

Examples and Comparative Examples Tables 4 and 5 show the contamination test of EPDM, acid anhydride, sulfur, and a rubber composition comprising a vulcanization accelerator having a boiling point of 100 ° C. or lower and not having an amine as a raw material after the vulcanization reaction. The results are shown in Table 6 as the results of the physical property test of the same rubber composition. In addition, a comparative example when no acid anhydride is added is also shown. The unvulcanized test shown in Table 6 was measured using a rheometer, and the test methods for physical properties of the vulcanized test piece, "tensile strength" and "elongation", were in accordance with JIS K6301.

[0021]

[Table 4]

[0022]

[Table 5]

[0023]

[Table 6]

Common to the Examples and Comparative Examples, the abbreviations are as follows: "EPDM" was obtained by using ethylidene norbornene as a diene monomer and manufactured by Nippon Synthetic Rubber Co., Ltd. (trade name: EP57C). "HAF carbon black" is manufactured by Tokai Carbon Co., Ltd. (trade name; Seast 3) "Process oil" is manufactured by Idemitsu Kosan Co., Ltd. (trade name; PW-90) "MBTS" is Sanshin Chemical Industry ( Co., Ltd. product (trade name;
Sanseller DM) "ZnBDC" is a product of Sanshin Chemical Industry Co., Ltd. (trade name; Sanseller BZ) "ZnEPDC" is a product of Sanshin Chemical Industry Co., Ltd. (trade name: Sanseller PX) "CMBT" is three Manufactured by Shin Kagaku Kogyo Co., Ltd. (trade name;
Sanseller HM) "TMTD" is a product of Sanshin Chemical Industry Co., Ltd. (trade name;
Sanseller TT) "MBT" is a product of Sanshin Chemical Industry Co., Ltd. (trade name; Sunseller M) "ZnMBT" is a product of Sanshin Chemical Industry Co., Ltd. (trade name: Sanseller MZ) "BBS" is Product of Shin-Chemical Industry Co., Ltd. (product name; Sanseller NS-G) "TMTM" is product of San-Shin Chemical Co., Ltd. (product name;
Sanseller TS) "TETD" is a product of Sanshin Chemical Industry Co., Ltd. (trade name;
Sansera TET-G) "TBTD" is a product of Sanshin Chemical Industry Co., Ltd. (trade name;
Sanseller TBT-P) "DPTT" is a product of Sanshin Chemical Industry Co., Ltd. (trade name;
Sansel TRA) "ZnMDC" is a product of Sanshin Chemical Industry Co., Ltd. (trade name; Sancella PZ) "ZnEDC" is a product of Sanshin Chemical Industry Co., Ltd. (product name: Sunceller EZ) "TeEDC" is Shin-Chemical Industry Co., Ltd. (trade name; Sunceller TE-G) "CuMDC" is Sanshin Chemical Co., Ltd. (trade name; Sunceller TT-CU) "FeMDC" is Sanshin Chemical Industry ( Phthalic anhydride manufactured by Sanshin Chemical Industry Co., Ltd. (trade name; retarder BC) Pyromellitic anhydride manufactured by Mitsubishi Gas Chemical Co., Inc. ) Manufactured by Daicel Chemical Industries, Ltd.
The itaconic anhydride manufactured by Iwata Chemical Co., Ltd. was used as the itaconic anhydride manufactured by Iwata Chemical Co., Ltd.

[0025]

From Tables 1 to 3, the rubber composition comprising EPDM, sulfur and a vulcanization accelerator which does not use amine having a boiling point of 100 ° C. or lower as a raw material has considerably reduced the contamination of coated plates. Further, it can be seen from Tables 4 and 5 that the addition of an acid anhydride to this system further improves the coloring prevention property of the coated plate. According to the results of the physical property test of the rubber composition shown in Table 6, the vulcanized physical properties of Examples 1 and 4 are almost at satisfactory levels as compared with Comparative Example 20, and the physical properties required for automobile cushion rubber and the like are retained. Is understood to be doing.

Therefore, according to the rubber composition of the present invention, sulfur vulcanization can be carried out, and the vulcanization physical properties are satisfactory, and at the same time, the coloring prevention property of the coated plate is remarkably improved. Therefore,
For example, it is apparent that it is extremely useful as a rubber composition for automobile cushion rubber and weather strip.

Claims (9)

[Claims] 1. An ethylene-propylene-diene monomer copolymer, an acid anhydride, sulfur, and a boiling point of 100 ° C. at atmospheric pressure.
A rubber composition containing, as a main component, a vulcanization accelerator not containing the following amine as a raw material. 2. An ethylene-propylene-diene monomer copolymer, an acid anhydride, sulfur, and a boiling point of 100 ° C. at atmospheric pressure.
A rubber composition comprising a vulcanization accelerator not containing the following amine as a raw material. 3. The rubber composition according to claim 1, wherein 0.1 to 5 parts by weight of an acid anhydride is mixed with 100 parts by weight of an ethylene-propylene-diene monomer copolymer. 4. The acid anhydride according to any one of claims 1 to 3, which is phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic anhydride, citraconic anhydride, itaconic anhydride. , 1 or 2 selected from tetrahydrophthalic anhydride, tetrahydromethylphthalic anhydride, ethylene glycol bisanhydrotrimellitate, glycerol trisanhydrotrimellitate, nadic acid anhydride, methylnadic acid anhydride
The rubber composition according to any one of claims 1 to 3, which is one or more kinds. 5. The acid anhydride according to claim 1 or 2 selected from ethylene-styrene-maleic anhydride copolymer resin and isobutylene-maleic anhydride copolymer resin.
The rubber composition according to any one of claims 1 to 3, which is one or more kinds. 6. The vulcanization accelerator according to claim 1 or 2, wherein N, N′-diphenylguanidine, N, N′-di-o-tolylguanidine, 2-mercaptobenzothiazole, dibenzothiazyl. Disulfide, zinc salt of 2-mercaptobenzothiazole, cyclohexylamine salt of 2-mercaptobenzothiazole, dicyclohexylamine salt of 2-mercaptobenzothiazole, N-cyclohexylbenzothiazyl-2-sulfenamide, N-oxydiethylene benzothiazyl-2-sulfenamide, N, N-
Dicyclohexyl benzothiazyl-2-sulfenamide, ethylenethiourea, tetrabutylthiuram disulfide, tetraoctylthiuram disulfide, dipentamethylenethiuram tetrasulfide, zinc dibutyldithiocarbamate, zinc ethylphenyldithiocarbamate, N-methylpiperazinothiocarbamyl-N The rubber composition according to claim 1 or 2, which is one kind or two or more kinds selected from'-methylpiperazinosulfenamide, zinc isopropylxanthogenate, and zinc dibutylphosphorodithioate salt. 7. A rubber composition comprising the rubber composition according to any one of claims 1 to 6 as a component and capable of preventing coloring of a coated metal in contact therewith. 8. A method for preventing staining and coloring of a coated metal plate with a rubber, which comprises using the rubber composition according to any one of claims 1 to 7. 9. The coated metal plate is a steel plate for automobiles.
The method for preventing staining and coloring according to.