JPS59226038A - Rubber composition having oil resistance and weather resistance - Google Patents

Abstract

PURPOSE:An oil-resistant and weather-resistance rubber composition having improved mechanical properties, obtained by blending unsaturated nitrile-conjugated diene copolymer rubber having a specific functional group with a halogenated EPDM. CONSTITUTION:(A) Unsaturated nitrile-conjugated copolymer rubber copolymerized with <=20wt%, preferably 0.5-10wt% copolymerizable monomer containing a functional group selected from amino group, epoxy group, and carboxyl group (e.g., dimethylaminoethyl acrylate, glycidyl ether, methacrylic acid) is blended with (B) halogenated ethylene-alpha-olefin-nonconjugated diene copolymer rubber containing 0.5-50wt%, preferably 0.5-10wt% halogen content in a weight ratio of A:B of (95:5)-(5:95), preferably (80:20)-(20:80).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to mechanically superior oil and weather resistant rubber compositions. More specifically, unsaturated nitrile containing at least one of an amine group, an epoxy group, and a carboxyl group.
The present invention relates to an oil- and weather-resistant rubber composition having excellent mechanical properties and comprising a conjugated diene copolymer rubber and a halogenated ethylene-α-olefin-nonconjugated diene copolymer rubber.

Acrylonitrile-butadiene copolymer comb (hereinafter referred to as NB)
Unsaturated nitrile-conjugated diene copolymer rubber represented by R) is widely used industrially as an oil-resistant rubber, but it has the drawback of poor weather resistance. NBR
It would be of great industrial value if weather resistance could be improved without impairing the excellent oil resistance. Various techniques have been proposed to solve this problem. For example, a method of blending (1) ethylene-propylene-nonconjugated diene copolymer rubber (hereinafter abbreviated as EPDM) with NBR (JP-A-56-109230, JP-A-57-96)
032), (2) EPDM and EPDM mixture grafted with vinyl chloride (JP-A-53-67754), or EPDM grafted with acrylonitrile (JP-A-57-1999)
-40544, JP-A-57-44647), and (3) a method of blending chlorinated polyethylene (JP-A-57-3836).

However, in the methods (1) and (2) above, EP1
) EPDM grafted with M or a polar monomer has low oil resistance.If the blending amount is increased to a level that improves the weather resistance of the NB tank, a problem arises in that the NBR0 oil resistance is sacrificed. Furthermore, in method (3), it is not easy to achieve co-vulcanization with chlorinated polyethylene and NBRO;
Vulcanizing agent selection is limited.

As a method to solve these problems, we first developed an unsaturated nitrile-conjugated diene copolymer rubber and a halogenated ethylene-α-
We have proposed an oil- and weather-resistant rubber composition containing an olefin-nonconjugated diene copolymer rubber as an essential component.

As a result of further extensive studies, the present applicant found that using a modified unsaturated nitrile-conjugated diene copolymer rubber having an amine group, an epoxy group, or a carboxyl group, halogenated ethylene-α-olefin-nonconjugated diene copolymer rubber can be used. The present invention was accomplished by discovering that the composition has excellent co-crosslinking properties with polymer rubbers, and further improves the vulcanization adhesion of the composition with other diene rubbers. That is, the present invention provides an amine group,
Unsaturated 2) IJ-conjugated diene copolymer com (A) halogenated ethylene-α having at least one functional group selected from epoxy and carboxyl groups
- olefin-nonconjugated diene copolymer rubber).

Unsaturated 2) IJsil- having a functional group used in the present invention
The conjugated diene copolymer rubber is a copolymerizable monomer having a functional group with a conjugated diene such as butadiene or isoprene and an unsaturated nitrile such as acrylonitrile or methacrylonitrile (at least one of Obtained by copolymerizing with nitrile.
O weight minus ≠ half. If the content of monomer (0) exceeds the weight ratio, it is undesirable because processability deteriorates.The content of acrylonitrile in the copolymer (4) is not particularly limited, but from the viewpoint of oil resistance-cold resistance balance. A weight ratio of 15 to 55 is desirable.

Among such monomers C), monomers having an amino group include dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate, diethylaminoethyl methacrylate, dipropylaminoethyl acrylate, diethylaminoethyl methacrylate, and diptyl. Examples include aminoethyl methacrylate, dibutylaminoethyl acrylate, diethylamine propyl methacrylate, and ethylaminoethyl methacrylate. Specific examples of monomers having epoxy groups include glycidyl acrylate, glycidyl methacrylate, glycidyl vinyl ether, and glycidyl allyl ether. Further, specific examples of the monomer having a carboxyl group include acrylic acid, methacrylic acid, itaconic acid, fumaric acid, and maleic acid.

Although any polymerization method may be used to produce the unsaturated nitrile-conjugated diene copolymer rubber having a functional group, it is generally obtained by emulsion polymerization. As polymerization initiators, conventional free radical catalysts such as peroxides, redox initiators, persulfates and azo compounds can be used. Various surfactants can be used as emulsifiers, but fatty acid salt soaps and sulfonate soaps are preferably used. Representative examples of molecular weight modifiers include sulfur compounds such as tertiary dodecyl mercaptan, normal dodecyl mercaptan, diinopropyl xanthogen disulfite, and halogen compounds such as carbon tetrachloride and carbon tetrabromide.

The polymerization is carried out in an oxygen-free reactor at 0-80°C. Monomers, emulsifiers, initiators, and other polymerization agents may be added in their entirety to the reaction system before the start of the reaction, or may be added in appropriate portions after the start of the reaction. Further, operating conditions such as temperature and stirring can be changed as appropriate during the reaction.

The polymerization method may be continuous, semi-batch or batch. Latex is coagulated with acidic or neutral aqueous solutions of metal salts or alcohol, and
and washed with neutral water.

The l-logenated ethylene-α-olefin-nonconjugated diene copolymer rubber used in the present invention consists of ethylene, propylene, α-olefins such as butene-1, ethylidenenorbornene, dicyclopentadiene, and flobenylnorbornene. , 1° or more, by converting an ethylene-α-olefin-nonconjugated diene copolymer rubber by a known method.

The type of halogen is preferably chlorine or bromine. Chlorination can be carried out, for example, by crushing the copolymer rubber into fine particles and contacting them with molecular chlorine gas, or by making the fine particles into an aqueous suspension and contacting them with molecular chlorine, or by using n-hexane, n-hebutane. Hydrocarbons such as carbon tetrachloride, tetrachloroethylene, and chlorobenzene are dissolved in a nano-chlorinated hydrocarbon, and the copolymer rubber is brought into contact with molecular chlorine in a homogeneous solution state. It will be done.

Bromination is carried out, as in the case of chlorination in a homogeneous solution state, by dissolving the copolymer rubber in a hydrocarbon or a halogenated hydrocarbon and bringing it into contact with molecular bromine.

In order to accelerate the reaction during these reactions, ultraviolet rays may be irradiated or peroxide may be added.

After the halogenation reaction, the process is carried out as follows: In the case of solid-phase chlorination, after the reaction is completed, excess chlorine is expelled through nitrogen gas to obtain a chlorinated copolymer rubber. After the reaction in a suspended state, the reaction product is washed with water and then dried to obtain a chlorinated copolymer rubber. After chlorination or bromination in solution, for example, the reaction product is treated with an aqueous solution of caustic soda, washed with water, and then steam stripped to obtain a chlorinated or brominated copolymer rubber.

If the halogen content of the halogenated ethylene-α-olefin-nonconjugated diene copolymer rubber used in the present invention is too low, the effects of the present invention cannot be obtained, and if it is too high, the balance of physical properties will be lost. Preferably 0.5-50
The weight ratio is particularly preferably 0.5 to 10 weight ratio.

Halogenated ethylene-α-olefin-nonconjugated diene copolymer rubber (B) and unsaturated nitrile-conjugated diene copolymer rubber having a functional group (4) thus produced
is mixed with ordinary rubber compounding agents such as carbon black, plasticizer, extender oil, anti-aging agent, vulcanization accelerator, vulcanizing agent, etc. using a mixer such as a roll or Banbury mixer to form a compounded rubber composition. be done. Unsaturated nitrile with functional group
Conjugated diene copolymer rubber and halogenated coral
9515 to 5/95 (weight 11; ratio).

9J4. (<tz ”/lo〜工'/go z”13
j.

Note that the purpose can be achieved even if the molecular weight of the unsaturated nitrile-conjugated diene copolymer rubber (4) having a functional group is small. In addition, non-halogenated ethylene α-olefin
Non-conjugated diene copolymer rubber and halogenated ethylene-α-
An olefin-nonconjugated diene copolymer rubber may be mixed with an unsaturated nitrile-conjugated diene copolymer rubber having a functional group at an appropriate chlorine content.

Similarly, an unsaturated IJ-conjugated diene copolymer rubber can also be mixed into the rubber composition.

The vulcanization system used in the present invention typically contains NB 1%,! :
Any material used for crosslinking EPDM may be used, and combinations of sulfur and various vulcanization accelerators are used. Examples of vulcanization accelerators include thiurams such as tetramethylthiuram disulfide and tetraethylthiuram disulfide;
- Thiazoles such as mercaptobenzothiazole, dibenzothiazyl disulfide, N-cyclohexyl-2-benzothiazolesulfenamide, imidazolines such as 2-mercaptoimidacillin, guanidines such as diphenylguanidine, dimethyldithiocarbamic acid Examples include dithiocarbamate salts such as zinc, and xanthate salts such as zinc ingropyl xanthate. The amount of vulcanization accelerator is preferably (1,1
~I Ophr, more preferably 0.2 to 5 phr.

Furthermore, metal compounds such as zinc oxide, magnesium oxide, litharge, calcium carbonate, and magnesium carbonate may be added as necessary. The amount of these compounding agents may be determined by taking into consideration the optimum vulcanization properties, processing stability, etc., and there is no restriction on the amount used.

When using an unsaturated nitrile-conjugated diene copolymer rubber having a carboxyl group, a low molecular organic diamine such as N, N, N', N'-tetramethylethylenediamine, N, N, N', N'- Tetramethyl-
1,6-hexanediamine, N, N, N', N'
-Tetramethyl-1,3-propanediamine, N.

N, N', N'-tetramethyl-benzidine, N
, N, N'.

N'-tetrahydroxyethyl-1,3-diamino-2
- It is desirable to mix the propatool, and it is preferable to mix the low-molecular organic diamine as soon as possible when mixing the rubber and compounding agents.

Vulcanization is usually carried out by heating at 120-200°C for 0.5-60 minutes.

The rubber composition according to the present invention is used in rubber products that require oil resistance and weather resistance, such as oil hoses, fuel hoses,
Hoses such as gas hoses, brake hoses, Freon hoses, cover materials for hoses, backings, gaskets, 0-links, belts, linings, oil seals,
Industrial parts such as dust boots, aircraft, and automobiles.

The test method for vulcanized rubber in the following examples is JIS K.
It was carried out according to 6301.

All amounts of compounding agents used, ) and rogene content are expressed in heavy parts and weight percent unless otherwise specified.

Example Rubber prototypes used in each example were produced as follows.

1. Preparation of unsaturated nitrile-conjugated diene copolymer rubber (4) having functional groups The copolymer rubber having amine groups, epoxy groups and carboxyl groups was polymerized in an autoclave at 30°C according to the recipe shown in Table 1. I did it.

At a polymerization conversion rate of 70, 0.2 parts by weight of diethylhydroxylamine was added to stop the polymerization. Subsequently, residual monomers were removed by steam distillation, and after adding 2 parts by weight of alkylated phenol per 100 parts by weight of rubber solid content, the mixture was coagulated in an aqueous calcium chloride solution. The resulting crumb was washed with water and then vacuum dried. The amount of bound acrylonitrile in the obtained rubbers (measured by the Kalepool method) was approximately 35% in all cases. The results are shown in Table 1.

(2) Preparation of halogenated ethylene-α-olefin-nonconjugated diene copolymer rubber (B) EP and DM manufactured by Nippon Synthetic Rubber were dissolved in a solvent in an autoclave, and the specified amounts of each were dissolved at 55 to 60°C. Chlorine was blown in or bromine was added to form chlorinated EPDM or brominated EPDM. The results are shown in Table 2.

(Left below) Table 1 The above rubber prototype and normal NBR (Japan Synthetic Rubber NBR)
23O8, bound acrylonitrile amount 35%), normal E
Physical properties were compared using various combinations of PDM (base BPDM in Table 2). Examples and comparative examples thereof are shown in Tables 3 to 6.

These physical properties were compared according to the following procedure.

N B R or amine group-containing, epoxy group or carboxyl group-containing N B II, (!: EPDM still) / rogogenated B P'DM are blended as shown below at the mixing ratios shown in Tables 3 to 6. After kneading in a 250CG plastomill according to the recipe, the vulcanizing agent and vulcanization accelerator were mixed in a roll, and the resulting mixture was press-vulcanized at 160°C for 20 minutes.
A tensile test, an oil resistance test, a weather resistance test, and a vulcanization adhesion test with SBR were conducted.

Blend Prescription Polymer 100 (Part) F1 ShiF Black 60 Naphthenic Oil 10 D OP 15 Zinc White No. 1
5 Stearic acid 1 (part) Accelerator CB
S'') 1.5 Sulfur 1.5so N-Cyclohexyl-2-benzothiazolylsulfenamide SBH used for vulcanization adhesion test with SBR (vulcanization adhesion between unvulcanized fabrics, 160°C x 30 minutes) The following formulation was used.

5BR41500100 (parts) HA Ii” Black 50 Aromatic Oil 5 Zinc White No. 1
3 Stearic acid 1 Accelerator B B 8”) 1 Sulfur 1 +2>Nt-butyl-2-penzothiazolylsulfenamide

Claims (1)

[Claims] Unsaturated nitrile-conjugated diene copolymer rubber having at least one functional group selected from amine group, epoxy group and carboxyl group and halogenated ethylene-
Consisting of α-olefin-nonconjugated diene copolymer rubber (B), the blending ratio of the above-mentioned prison component and component (B) is 95:5 to 5.
:95 (weight ratio)