JP3265741B2 - Radiator hose - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to a radiator hose .

[0002]

2. Description of the Related Art Conventionally, as a radiator hose, an ethylene-α-olefin copolymer rubber represented by ethylene-propylene rubber (EPM) or ethylene-propylene-non-conjugated diene rubber (EPDM) or ethylene-α-
Olefin-non-conjugated diene copolymer rubbers are widely used. Here, the ethylene-α-olefin copolymer rubber and the ethylene-α-olefin-nonconjugated diene copolymer rubber are used as vulcanized rubber vulcanized using an organic peroxide. In this case, for the purpose of preventing aging, it has been common technical knowledge to use a zinc-containing compound typified by zinc white (zinc oxide) in a rubber composition as one of the essential components. However, when a rubber composition containing a zinc-containing compound is used as a radiator hose, zinc is eluted in a cooling medium, which causes inconvenience to a mechanical system,
The electrical conductivity provided by zinc causes an electrical corrosion effect, which results in cracks in the radiator hose,
Further, there is a problem that the crack is easily enlarged.

[0003]

SUMMARY OF THE INVENTION In view of this situation, an object of the present invention is to provide an ethylene-α-olefin copolymer rubber or an ethylene-α-olefin-nonconjugated diene copolymer rubber as a main component. A vulcanized rubber composition obtained by vulcanizing a rubber composition having excellent anti-aging properties without using a zinc-containing compound with the above disadvantages.
It is to provide a used radiator hose.

[0004]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have reached the present invention. That is, the present invention provides a rubber composition containing the following (A) to (C) and not containing a compound having zinc .
(A) The content of (B) per 100 parts by weight is 0.1 to
(C) per 100 parts by weight of (A)
The present invention relates to a radiator hose using a vulcanized rubber composition obtained by vulcanizing a rubber composition having a content of 10 to 200 parts by weight with an organic peroxide. However,
In terms of the content, ethylene-α-olefin
Copolymer rubber and ethylene-α-olefin-non-conjugated
When the diene copolymer rubber is used in combination, the amount of (A)
Based on the total amount of rubber. (A) Ethylene-α-olefin copolymer rubber and / or ethylene-α-olefin-non-conjugated diene copolymer rubber (B) N, N′-bis [3- (3,5-di-t-butyl) -4-hydroxyphenyl) propionyl] hydrazine, N, N'-dibenzal- (oxalyldihydrazide) and 2,2'-oxamidobis- [ethyl-3-
(3,5-di-t-butyl-4-hydroxyphenyl)
At least one compound selected from the group consisting of (propionate) (C) carbon black

[0005]

[0006]

The details will be described below. Examples of the α-olefin in the ethylene-α-olefin copolymer rubber and the ethylene-α-olefin-nonconjugated diene copolymer rubber of the present invention include propylene, 1-butene, 1-
Pentene, 1-hexene, 4-methyl-1-pentene,
Examples thereof include 1-octene and 1-decene, among which propylene is preferred. Examples of the non-conjugated diene include 1,4-hexadiene, 1.6-octadiene,
2-methyl-1,5-hexadiene, 6-methyl-1.
Linear non-conjugated dienes such as 5-heptadiene, 7-methyl-1-6-octadiene; cyclohexadiene, dicyclopentadiene, methyltetrahydroindene, 5-
Cyclic non-conjugated dienes such as vinyl norbornene, 5-ethylidene-2-norbornene, 5-methylene-2-norbornene, 5-isopropylidene-2-norbornene, 6-chloromethyl-5-isopropylenyl-2-norbornene; 2 -3-diisopropylidene-5-norbornene, 2-ethylidene-3-isopropylidene-5-norbornene, 2-propenyl-2,2-norbornadiene, 1,3,7-octatriene, 1,4,9-decatriene Trienes, such as 1,4-
Hexadiene, dicyclopentadiene and 5-ethylidene-2-norbornene are preferred.

[0008] As the ethylene-α-olefin copolymer rubber or ethylene-α-olefin-non-conjugated diene copolymer rubber, an oil-extended rubber containing extended oil may be used.

In the present invention, as the copolymer component,
In addition to the ethylene-α-olefin copolymer rubber and the ethylene-α-olefin-non-conjugated diene copolymer rubber, an ethylene- (meth) acrylate-based copolymer can be used. In addition, it is possible to further improve the oil resistance of the obtained vulcanized rubber composition. Here, the ethylene- (meth) acrylate-based copolymer means a copolymer containing ethylene and acrylate and / or methacrylate.

As the acrylate ester and methacrylate ester, esters composed of alcohols having 1 to 8 carbon atoms are preferable. For example, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate,
N-butyl acrylate, n-butyl methacrylate,
Acrylic acid tert-butyl, methacrylic acid ter
t-butyl, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate and the like. These may be used alone or in a combination of two or more.

The ratio (molar ratio) of ethylene / (meth) acrylate is usually 50/50 to 85/15, preferably 58/42 to 80/20. When the proportion of ethylene is too small, the embrittlement point of the copolymer becomes high, and it may be difficult to use the elastomer at a low temperature.
On the other hand, when the proportion of ethylene is excessive, the crystallinity of the copolymer becomes high, and sufficient elastomer elasticity may not be obtained.

The ethylene- (meth) acrylic acid ester-based copolymer is a kind of unsaturated glycidyl ester, acid anhydride, and unsaturated compound having a carboxylic acid group (hereinafter sometimes referred to as "third component"). It may contain the above. Examples of the unsaturated glycidyl ester include glycidyl acrylate, glycidyl methacrylate, diglycidyl itaconate, triglycidyl butenetricarboxylate, glycidyl p-styrenecarboxylate described in JP-B-46-45085. Examples of the unsaturated compound having a carboxylic acid group include acrylic acid, methacrylic acid, maleic acid, and a half esterified product of maleic acid, and examples of the acid anhydride include maleic anhydride. The amount of the third component to be used is from 0.05 to the total amount of both the ethylene and the (meth) acrylate.
It is 5 mol%, preferably 0.1 to 3 mol%.

It is also possible to copolymerize the ethylene copolymer of the present invention with a comonomer that can be copolymerized with other ethylene. Specific examples include isobutylene, styrene and derivatives thereof, vinyl acetate, and halogenated olefins such as tetrafluoroethylene and hexafluoropropylene.

The ethylene- (meth) acrylic acid ester-based copolymer is defined by JIS K6791.
A copolymer having a melt index at 90 ° C. of usually 0.5 to 500 g / 10 min, preferably 0.5 to 50 g / 10 min is used.

When an ethylene- (meth) acrylate copolymer is used, ethylene-α-olefin copolymer rubber, ethylene-α-olefin-nonconjugated diene copolymer rubber and ethylene- (meth) acrylic acid are used. The mixing ratio of the ester copolymer is preferably in the range of 50/50 to 99/1 (weight ratio). If the ratio is too small, the tensile strength of the vulcanized rubber composition, heat resistance and compression set may be reduced, while if the ratio is too large,
The effect of improving oil resistance may be insufficient. In addition, ethylene-α-olefin copolymer rubber or ethylene-α
The above value in the case of using an oil-extended rubber as the olefin-non-conjugated diene copolymer rubber is a value based on the weight of only the polymer component excluding the extension oil (the same applies hereinafter).

In the present invention, N, N'-bis [3- (3,5
-Di-t-butyl-4-hydroxyphenyl) propionyl] hydrazine ((1) below), N, N'-dibenzal- (oxalyldihydrazide) ((2) below) and 2,2'-oxamidobis- [ethyl- 3- (3,5-
At least one compound selected from the group consisting of [di-t-butyl-4-hydroxyphenyl) propionate] ((3) below) is used.

[0017]

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The above compounds may be used singly or as a mixture of two or more. When the ethylene-α-olefin copolymer rubber and / or the ethylene-α-olefin-non-conjugated diene copolymer rubber is used, and the ethylene- (meth) acrylate ester-based copolymer is used, -100 parts by weight of the total amount of all copolymers including the (meth) acrylic acid ester-based copolymer (hereinafter sometimes referred to as "copolymer component").
0.1 to 10 parts by weight, preferably 0.3 to 6 parts by weight. When the amount of the compound is too small, the anti-aging property is insufficient, while when the amount of the compound is too large, the anti-aging effect is saturated, which may be uneconomical. When two or more compounds are used as a mixture, the above amount is based on the total amount of all the compounds.

In the present invention, carbon black is used to maintain strength and weather resistance at a high level. The amount used is 10 to 10 parts by weight per 100 parts by weight of the copolymer component.
It is 200 parts by weight, preferably 40 to 140 parts by weight.

In the present invention, N, N'-bis [3-
(3,5-di-t-butyl-4-hydroxyphenyl)
Propionyl] hydrazine, N, N'-dibenzal-
(Oxalyl dihydrazide) and 2,2'-oxamidobis- [ethyl-3- (3,5-di-t-butyl-4-
It is particularly important to use at least one compound selected from the group consisting of [hydroxyphenyl) propionate] and not to use a compound having zinc. This eliminates the aforementioned problems associated with zinc, and tensile strength, elongation, and the like associated with use in a high-temperature air atmosphere and high-temperature oil.
Aging phenomena in which characteristics such as hardness deteriorate can be prevented.

As the organic peroxide used in the present invention, organic peroxides usually used for crosslinking rubber can be used, such as di-t-butyl peroxide and t-butyl peroxide.
Butylcumyl peroxide, dicumyl peroxide, α, α-bis (t-butylperoxyisopropyl) benzene, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl −2,5
-Di (t-butylperoxy) hexyne-3,1,1-
Bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, n-butyl-4,4-bis (t-butylperoxy) valerate, 2,2-bis (t-butylperoxy) butane, 2,2-bis (t-butylperoxy) octane and the like.

The amount of the organic peroxide used depends on the amount of the copolymer component 1
The amount is preferably 1 to 10 parts by weight, more preferably 2 to 6 parts by weight, per 100 parts by weight. If the amount is too small, the crosslinking density is low, and the mechanical strength of the vulcanized rubber composition is insufficient. On the other hand, if the amount is too large, problems such as foaming during vulcanization molding may occur. In order to improve the crosslinking efficiency at the time of vulcanization with an organic peroxide, known crosslinking auxiliaries such as p, p'-dibenzoylquinone dioxime, quinone dioxime, triallyl cyanurate, sulfur, ethylene dimeta Acrylate, N, N′-m-phenylenebismaleimide, triallyl isocyanurate,
You may use trimethylol propane trimethacrylate, a metal acrylate, etc.

In order to obtain a vulcanized rubber composition using the rubber composition of the present invention, for example, a copolymer component, N, N'-
Bis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyl] hydrazine, N, N'-dibenzal- (oxalyldihydrazide) and 2,2'-oxamidobis- [ethyl-3- (3 , 5-di-t-butyl-4-hydroxyphenyl) propionate], carbon black and organic peroxide, as required, an antioxidant and a vulcanization accelerator. , Processing aids, stearic acid, reinforcing agents, fillers, plasticizers, softeners, etc. (limited to those that do not contain zinc) by using a conventional kneading machine such as a roll or Banbury. A vulcanizable rubber composition, usually 120 ° C. or higher, preferably 150 to 220
Vulcanization may be performed at a temperature of about 1 to 30 minutes. The vulcanization can be applied to any of press vulcanization and steam vulcanization.

The vulcanized rubber composition obtained from the rubber composition of the present invention can be processed into a radiator hose by a usual method, and the radiator hose is an extremely excellent radiator hose having the characteristics described above. is there.

[0025]

Next, the present invention will be described with reference to Examples and Comparative Examples. Examples 1-4, Comparative Examples 1-12 and Reference Example 1 As a copolymer component, ethylene-propylene-ethylidene norbornene copolymer rubber (E50 manufactured by Sumitomo Chemical Co., Ltd.)
5. Mooney viscosity ML _{1 + 4} 100 ° C. 75, ethylene content 49% by weight, 95 parts by weight of iodine value 24) and ethylene-propylene-ethylidene norbornene copolymer rubber (E601F manufactured by Sumitomo Chemical Co., Ltd., Mooney viscosity ML _{1 + 4)} 1
21 ° C. 63, ethylene content 57% by weight, iodine value 1
5 parts by weight (2,70 phr oil extended product) (the amount based on the polymer component excluding the extender oil) was mixed and used. The copolymer component 1
100 parts by weight, 97 parts by weight of Asahi 50HG (Carbon Black manufactured by Asahi Carbon Co., Ltd.), and Sampar 2280 (paraffinic oil manufactured by Sun Oil Co., Ltd.) Parts by weight, Structor WB212 (Schill & Seelach)
er company's processing aid) 2 parts by weight, acrylic ester ED
2 parts by weight (crosslinking aid manufactured by Mitsubishi Kasei Co., Ltd.) and 1 part by weight of stearic acid were added, and the mixture was kneaded for 5 minutes at a rotor rotation speed of 60 rpm using a 1500 ml Banbury mixer adjusted to 90 ° C. Thereafter, using an 8-inch open roll, 7 parts by weight of DCP (40% dicumyl peroxide manufactured by NOF CORPORATION) was added and kneaded to obtain a rubber composition. Next, the rubber composition was press-vulcanized at 170 ° C. for 15 minutes to obtain a vulcanized rubber composition. The evaluation of the vulcanized rubber composition was performed according to JIS K6301. Also,
The heat resistance was evaluated by the rate of change in physical properties before and after standing at 160 ° C. for 94 hours in air, and the oil resistance was determined by ASTM.
No. Evaluation was made based on the rate of change in physical properties before and after standing at 100 ° C. for 22 hours in 2 oils. The results are shown in Tables 1 to 3.

Examples 5 to 8 Ethylene-propylene-ethylidene norbornene copolymer rubber (E56 manufactured by Sumitomo Chemical Co., Ltd.) was used as a copolymer component.
7, Mooney viscosity ML _{1 + 4} 100 ° C. 50, ethylene content 50% by weight, iodine value 5) and ethylene-propylene-ethylidene norbornene copolymer rubber (E601F manufactured by Sumitomo Chemical Co., Ltd., Mooney viscosity ML _{1 + 4} 121 ° C. 63) ,
Ethylene content 57% by weight, iodine value 12, 70 phr
Oil extended product) and ethylene-methyl acrylate copolymer (EMA2152, manufactured by Sumitomo Chemical Co., Ltd., ethylene / methyl acrylate molar ratio 68/32, JIS K 6791 melting index (190 ° C.) 7) at the ratios shown in Table 4. The procedure was the same as in Example 1, except for the fact that Table 4 shows conditions and results
It was shown to.

The following can be understood from the results. In Reference Example 1, zinc oxide was added. On the other hand, the heat resistance of Comparative Example 1 in which no zinc oxide was used was reduced. However, Examples using the compound of the present invention without using zinc oxide have particularly excellent heat resistance and maintain a satisfactory level of oil resistance. In contrast, Comparative Examples 2 to 12 using compounds other than the compound of the present invention without using zinc oxide are inferior in heat resistance and oil resistance. In Examples 6 to 9 using ethylene-methyl acrylate in combination, the effect of improving oil resistance was remarkable.

[0028]

Table 1--------------------------------------------------------------------------------------------------------------------- 4 Compound added * 1 Type Z-E1 E2 E3 E4 Amount 5-5 5 5 5 Evaluation Vulcanizate properties T _B Tensile strength Kgf / cm ² 155 150 153 152 155 153 EB E _B elongation% 250 280 280 250 270 280 H _S hardness JIS-A 68 67 68 69 67 66 Heat resistance Δ T _B % +11 -51 -5 -15 -4 -7 Δ E _B % -19 -56 -19 -20 -15 -20 -20 Δ H _S point + 10 +10 +5 +7 +6 +8 Oil resistance Δ T _B % -31 -35 -35 -32 -40 -38 Δ E _B % -38 -38 -32 -28 -38 -32 Δ H _S point- 20 -20 -18 -17 -17 -17 -17 Δ V% * 2 +75 +72 +71 +71 +82 +83 −−−−−−−−−−−−−−−−−−−−−−−− −−−−−−−−−−−−−−

[0029]

[Table 2] ---------------------------------------- Comparative Example 23 4 5 6 7 Compound added * 1 Type C2 C3 C4 C5 C6 C7 Amount 5 5 5 5 5 5 Evaluation Vulcanizate Properties T _B Tensile Strength Kgf / cm ² 155 122 126 111 147 144 E _B Elongation% 240 450 480 500 260 350 H _S Hardness JIS- A 66 59 63 61 68 66 Heat resistance Δ T _B % -57 -45 +14 -30 -38 0 Δ E _B % -71 -80 -35 -82 -77 -49 Δ H _S point +10 +19 +5 +18 +15 +10 Oil resistance Δ T _B % -32 -48 -50 -56 -34 -44 Δ E _B % -29 -42 -42 -50 -31 -40 Δ H _S point -18 -28 -34 -26 -20 -26 Δ V% * 2 +73 +99 +103 +114 +74 +88 −−−−−−−−−−−−−−−−−−−−−−−−−−−−− −−−−−−−−

[0030]

Table 3 −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Comparative Example 8 9 10 11 12 Compound added * 1 Type C8 C9 C10 C11 C1 Amount 5 5 5 5 5 Evaluation Vulcanizate properties T _B Tensile strength Kgf / cm ² 101 134 63 20 153 E _B elongation% 500 370 620 790 270 270 H _S hardness JIS-A 59 65 60 56 63 Heat resistance Δ T _B % +8 +9 +105 +420 -5 Δ E _B % -76 -55 -58 -72 -41 Δ H _S point +24 +11 +12 +14 +11 Oil resistance Δ T _B % -58- 46 -54 -70 -37 Δ E _B % -50 -40 -52 -57 -33 Δ H _S point -35 -27 -45 -49 -18 Δ V% * 2 +120 +92 +145 +179 +80 −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

[0031]

[Table 4] ------------------------------------------------------------------------ Example 5 6 7 8 9 Copolymer component wt * 3 E601F (Table 4)---------------------------------------- 30 30 30 30 30 E567 70 60 50 40 20 EMA2152 0 10 20 30 50 Compound added * 1 Type E1 E1 E1 E1 E1 Amount 0.5 0.5 0.5 0.5 0.5 Evaluation Vulcanizate properties T _B Tensile strength Kgf / cm ² 160 141 132 127 112 E _B elongation% 310 310 310 320 300 H _S hardness JIS-A 67 67 68 67 67 Heat resistance Δ T _B % -33 -32 -33 -24 -20 Δ E _B % -23 -32 -32 -28 -13 Δ H _S point +3 +3 +4 +6 +8 Oil resistance Δ T _B % -24 -18 -19 -20 -15 -15 E _B % -35 -32 -29 -34 -27 Δ H _S point -20 -20 -22 -20 -19 Δ V% * 2 +81 +75 +70 +61 +46 Compression set% * 4 33 39 37 41 51 −−−−−−−−−−−−−−− −−−−−−−−−−−−−−−−−−−−

* 1 Compounds added Z: zinc white (zinc oxide) E1: IRGANOX (Irganox) MD102
4 (N, N'-bis [3- manufactured by Ciba Geigy)
(3,5-di-t-butyl-4-hydroxyphenyl)
Propionyl] hydrazine) E2: Eastman Inhibitor OABH
(N, N'-dibenzal- (oxalyldihydrazide) manufactured by Eastman Kodak Company) E3: Naugard (Nogard) XL-1 (Uni
2,2'-oxamidobis- [ethyl-3- (3,5-di-t-butyl-) manufactured by Royal Chemical
4-Hydroxyphenyl) propionate] E4: Additive manufactured by Adeka Argus Chemical Co., Ltd.
kZS19 C1: IRGANOX (Irganox) 1010
(Pentaerythritol tetrakis [3, (3,5-di-t-butyl-4-hydroxyphenyl) propionate] manufactured by Ciba Geigy)

C2: Sanol 770 (bis (2,2,6,6-tetramethyl-4-piperidyl) manufactured by Sankyo Pharmaceutical Co., Ltd.)
Sebacate) C3: Nocrack NS10N (Ouchi Shinkosha 1,3)
-Bis (dimethylaminopropyl) -2-thiourea) C4: Antigen NBC (nickel dibutyldithiocarbamate manufactured by Sumitomo Chemical Co., Ltd.) C5: Antigen W (1,1-bis (4-hydroxyphenyl) cyclohexane manufactured by Sumitomo Chemical Co., Ltd.) C6: Sumilizer MB (2-mercaptobensuimidazole manufactured by Sumitomo Chemical Co., Ltd.)

C7: Antigen RD (a polymer of 2,2,4-trimethyl-1,2-dihydroquinoline manufactured by Sumitomo Chemical Co., Ltd.) C8: Naugard (Nogard) 445 (Unir)
oyl Chemical's substituted diphenylamine C9: Nocrack White (Ouchi Shinko's N, N'-
Di-2-naphthyl-p-phenylenediamine) C10: Antigen DA (reaction product of phenyl-β-naphthylamine and acetone manufactured by Sumitomo Chemical Co., Ltd.) C11: Antigen PA (phenyl-α-naphthylamine manufactured by Sumitomo Chemical Co., Ltd.) Amount of compound: expressed in parts by weight per 100 parts by weight of rubber polymer component excluding extender oil * 2 ΔV%: volume change rate * 3 Copolymer component: The meanings of the symbols are as described above. The numerical values are parts by weight of the mixture, and the oil-extended rubber E601F is the weight based on the polymer component excluding the extending oil. * 4 Compression set: The vulcanizate at 170 ° C. for 20 minutes was measured for compression set at 160 ° C. for 22 hours by the VW method.

[0035]

As described above, according to the present invention, the ethylene-α-olefin copolymer rubber or ethylene-α
-Using a vulcanized rubber composition obtained by vulcanizing a rubber composition having an olefin-non-conjugated diene copolymer rubber as a main component, not using a zinc-containing compound, and having excellent anti-aging properties.
Radiator hose could be provided.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI C08K 5:25) C08K 5:25) (C08L 23/16 (C08L 23/16 23:08) 23:08) (56) Reference Document JP-A-2-36247 (JP, A) JP-A-3-207733 (JP, A) JP-A-63-46246 (JP, A) JP-A-63-110231 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) C08L 23/00-23/36 C08K 3/00-13/08

Claims (2)

(57) [Claims] 1. A rubber composition containing the following (A) to (C) and not containing a compound having zinc :
(A) The content of (B) per 100 parts by weight is 0.1 to
(C) per 100 parts by weight of (A)
A radiator hose using a vulcanized rubber composition obtained by vulcanizing a rubber composition having a content of 10 to 200 parts by weight with an organic peroxide. However, in the above content,
(A) ethylene-α-olefin copolymer rubber and
And ethylene-α-olefin-non-conjugated diene copolymer
The amount of (A) when the rubber is used together is based on the total amount of both rubbers.
Standard. (A) Ethylene-α-olefin copolymer rubber and / or ethylene-α-olefin-non-conjugated diene copolymer rubber (B) N, N′-bis [3- (3,5-di-t-butyl) -4-hydroxyphenyl) propionyl] hydrazine, N, N'-dibenzal- (oxalyldihydrazide) and 2,2'-oxamidobis- [ethyl-3-
(3,5-di-t-butyl-4-hydroxyphenyl)
At least one compound selected from the group consisting of (propionate) (C) carbon black 2. A rubber composition containing (A) to (C) according to claim 1 and the following (D) and not containing a compound having zinc, wherein the total of (A) and (D) is 100
The content of (B) per part by weight is 0.1 to 10 parts by weight.
Yes, the total amount of (A) and (D) per 100 parts by weight
The content of (C) is 10 to 200 parts by weight, and (A) /
The mixing ratio (weight ratio) of (D) is 50/50 to 99/1.
A radiator hose using a vulcanized rubber composition obtained by vulcanizing a rubber composition (weight ratio) with an organic peroxide. (D) Ethylene- (meth) acrylate copolymer