JP3367309B2 - Hydrogenated nitrile rubber composition - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a hydrogenated nitrile rubber composition. More specifically, it relates to a hydrogenated nitrile rubber composition having excellent resistance to Freon R12 and Freon R134a.

[0002]

_2. Description of the Related Art Currently, hydrogenated nitrile rubber is used for rubber parts (O-rings, packings, etc.) of air conditioners that use Freon R12 (CCl ₂ F ₂ ) as a refrigerant. Freon R12 is Freon R134a (CH ₂ FC
It is going to be an alternative to the F _3). However, the hydrogenated nitrile rubber has a drawback that it foams when it comes into contact with Freon R134a.

Japanese Laid-Open Patent Publication No. 6-271705 discloses a fluorocarbon R134a.
A hydrogenated nitrile rubber composition having resistance to is described, and the composition is a hydrogenated nitrile rubber 100.
2 to 15 parts by weight of crosslinking agent, 0.1 to 10 parts by weight of crosslinking aid, 1 to 20 parts by weight of metal oxide, 100 to 180 parts by weight of reinforcing agent and 5 to 20 parts by weight of plasticizer per parts by weight. Is included.

As the metal oxide, those generally used as additives for rubber are said to be used, and alkaline ones such as ZnO, SbO, MgO, PbO and CaO are preferably used. It is considered that these metal oxides are added as an acid acceptor. Further, it is described that the reinforcing agent is not preferable when used in a ratio of less than 100 parts by weight because swelling due to Freon R134a increases.

[0005]

When a hydrogenated nitrile rubber is used as a vulcanization molding material for a sealing material that comes into contact with Freon, the vulcanized product becomes harder as the proportion of the reinforcing agent added to the vulcanization material naturally increases. Since the mountability and sealing performance may be impaired, the reinforcing agent is often used in an amount less than 100 parts by weight per 100 parts by weight of hydrogenated nitrile rubber, and in such a case, the CFC resistance R134a is impaired. This is as described in the above-mentioned publication. Also, when MT carbon black is used as a reinforcing agent, foaming is observed at the addition of about 100 to 120 parts by weight, and at about 130 to 150 parts by weight, the addition amount of the plasticizer and the vulcanizing agent and the vulcanization condition are In some cases, foaming may occur. Furthermore,
Even when 100 parts by weight or more of thermal black having a low reinforcing property is used, the CFC resistance may be impaired when the hardness is lowered by adding a plasticizer or the like.

At present, it is going to be replaced by Freon R12 by Freon R134a, but there are various problems with it, and it takes a considerable time before all Freon R12 is replaced by Freon R134a. The current situation is to have one. As a measure during this period, Freon R12 and Freon R134a are to be used respectively, and therefore there is a demand for a rubber composition that can be used for both Freon R12 and Freon R134a refrigerants.

The object of the present invention is to provide excellent resistance to both Freon R12 and Freon R134a refrigerants, regardless of the proportion of addition of reinforcing agents and fillers to hydrogenated nitrile rubber. It is to provide a hydrogenated nitrile rubber composition capable of giving a vulcanized product showing

[0008]

The object of the present invention is as follows.
Containing about 20 to 180 parts by weight of reinforcing agent or filler, about 0.5 to 100 parts by weight of Fe ₂ O ₃ or TiO ₂ and about 1 to 10 parts by weight of organic peroxide per 100 parts by weight of hydrogenated nitrile rubber. Achieved by a vulcanized hydrogenated nitrile rubber composition.

As the hydrogenated nitrile rubber, a copolymer rubber of acrylonitrile and butadiene (nitrile rubber) is hydrogenated, and the amount of carbon-carbon double bonds in the main chain of the molecule is about 20%.
The following is used, preferably 10% or less. Regarding its Mooney viscosity ML _{1 + 4} (100 ° C), it is 60-90.
Although those having a degree of use are used, those having a degree of 100 or more are preferably used (see Japanese Patent Laid-Open No. 5-65,369). In practice, commercially available products such as those manufactured by Nippon Zeon's Zet Pole series are used.

As the reinforcing agent or filler, fine silica, activated calcium carbonate and the like are used, but carbon black is generally used. As carbon black, furnace black produced by incompletely burning oil, thermal black produced by pyrolyzing natural gas, etc. are generally used, and these are commercially available products for the rubber industry as they are. Can be used.
These reinforcing agents are generally used in a proportion of about 20 to 180 parts by weight, preferably about 40 to 150 parts by weight, per 100 parts by weight of hydrogenated nitrile rubber.

Fe ₂ O ₃ and TiO ₂ have an average particle size of about 0.05 to 1
Since it is about 0 μm, which is smaller than that of the conventional filler, even if it is compounded, the sealing property is not impaired. These are used in a proportion of about 20 to 180 parts by weight, preferably about 2 to 30 parts by weight, per 100 parts by weight of hydrogenated nitrile rubber. If the addition ratio is less than this, the effect of improving the flon resistance, which is the object of the present invention, cannot be obtained, while if it is used at a ratio higher than this, kneading workability (roll processability)
Will be damaged.

When other metal oxides which are considered to act as a conventionally known acid acceptor instead of Fe ₂ O ₃ or TiO ₂ , such as ZnO and MgO, are used, a large amount of the reinforcing agent is not used. As far as it is, the improvement of the CFC resistance, especially the CFC resistance R134a is not performed.

The organic peroxide used as a cross-linking agent for hydrogenated nitrile rubber in an amount of about 1 to 10 parts by weight, preferably about 2 to 8 parts by weight, per 100 parts by weight of the hydrogenated nitrile rubber is, for example, ditertiary butyl peroxide. Oxide, dicumyl peroxide,
Tertiary butylcumyl peroxide, 1,1-di (tertiary butylperoxy) -3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-di (tertiary butylperoxy) hexane, 2 , 5-Dimethyl-2,5-di (tert-butylperoxy) hexyne-3,1,3-di
(Tertiary butylperoxyisopropyl) benzene, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, tert-butylperoxybenzoate, tert-butylperoxyisopropyl carbonate, n-butyl-4,4 -Di (tertiary butylperoxy) valerate or the like is used.

In the rubber composition, in addition to the above essential components, polyfunctional compounds such as triallyl (iso) cyanurate, trimethylolpropane trimethacrylate and triallyl trimellitate, talc, clay, graphite and calcium silicate. Commonly used in rubber industry such as fillers, processing aids such as stearic acid, palmitic acid, paraffin wax, acid acceptors such as magnesium oxide, hydrotalcite, epoxy resin, anti-aging agents, plasticizers, etc. The compounding agent used is appropriately added and used as necessary.

The rubber composition is prepared by kneading using an intermix, a kneader, a Banbury mixer, or an open roll, and the vulcanization thereof is performed by an injection molding machine, a compression molding machine, or a vulcanization machine. Generally, it is performed by heating at about 150 to 200 ° C for about 3 to 60 minutes using a sulfur press or the like, and at about 120 to 200 ° C for about 1
Secondary vulcanization is performed by heating for ~ 24 hours.

[0016]

EFFECT OF THE INVENTION Fe ₂ O ₃ or TiO is added to hydrogenated nitrile rubber.
_{When 2} is mixed, there is no problem in dispersibility and the like and uniform mixing is possible. When such a hydrogenated nitrile rubber composition is crosslinked with an organic peroxide, even if a reinforcing agent or a filler is added to the hydrogenated nitrile rubber, regardless of the addition ratio thereof, Freon R12, R134a A vulcanizate having excellent resistance to both refrigerants is obtained. Moreover, the mold stain property is not observed.

Therefore, the hydrogenated nitrile rubber composition according to the present invention is a machine / equipment device using both of CFC R12 and CFC R134a, for example, O-rings and packings used in compressors for air conditioners and refrigerators.
It can be suitably used as a vulcanization molding material for a sealing material such as a lip seal.

[0018]

EXAMPLES The present invention will now be described with reference to examples.

Example 1 100 parts by weight of hydrogenated NBR (Zetpol 2010H manufactured by Zeon Corporation) [Nitrile content 36%, iodine value 11, ML _{1 + 4} (100 ° C) 130] SRF carbon black 50〃 stearic acid 0.5〃 oxidation Zinc 5 〃 1,3-bis (tertiary butylperoxyisopropyl) benzene 3 〃 Trimethylolpropane triacrylate 10 〃 Fe ₂ O ₃ (average particle size 0.2 μm) 5 〃 Pressure kneader and open roll Knead the mixture and press vulcanize at 170 ℃ for 20 minutes and
It was vulcanized and molded into a 150 × 150 × 2 mm sheet by oven vulcanization at 50 ° C. for 1 hour.

Example 2 In Example 1, the amount of Fe ₂ O ₃ was changed to 15 parts by weight.

Example 3 100 parts by weight of hydrogenated NBR (Zeonpol 2010H manufactured by Zeon Corporation) [Nitrile content 36%, iodine value 11, ML _{1 + 4} (100 ° C.) 130] MT carbon black 130 〃 stearic acid 0.5 〃 oxidation Zinc 5 〃 1,3-bis (tertiary butylperoxyisopropyl) benzene 6 〃 Di (butoxyethyl) adipate 10 〃 Fe ₂ O ₃ (average particle size 0.2 μm) 5 〃 Pressure kneader and open Knead using a roll, press vulcanize the kneaded product at 170 ℃ for 20 minutes and
It was vulcanized and molded into a sheet of 150 × 150 × 2 mm by oven vulcanization at 60 ° C. for 3 hours.

Comparative Example 1 In Example 1, Fe ₂ O ₃ was not used.

Comparative Example 2 In Example 2, the same amount (15 parts by weight) of C ₂ was used instead of Fe ₂ O _3.
r ₂ O ₃ was used.

Comparative Example 3 In Example 3, Fe ₂ O ₃ was not used.

With respect to the vulcanized sheets obtained in each of the above Examples and Comparative Examples, normal physical properties (JIS K-6301 compliant),
Freon resistance (24 at 40 ° C in Freon R12 or Freon R134a
After dipping for an hour, observe the presence or absence of foaming when heated in an oven at 160 ° C for 0.5 hours) and mold fouling property (use a cleaning mold to measure the number of shots until product chipping due to mold fouling) And observation was performed, and the results as shown in the following Table 1 were obtained. Table 1 Item actual -1 actual -2 actual -3 ratio -1 Ratio -2 ratio -3 [normal physical properties] Hardness (JIS A) 77 78 79 77 78 80 Tensile strength (MPa) 29.0 27.6 18.6 29.4 28.5 18.2 Elongation (%) 330 350 180 330 330 180 [CFC resistance] CFC R12 No foam No foam No foam No foam No foam No CFC R134a 〃 〃 〃 Foam Yes Foam Yes Foam [Stain resistance] Number of shots (times) )>11>11>11>11>11> 11

Example 4 100 parts by weight of hydrogenated NBR (Zeonpol 2020 manufactured by Zeon Corporation) [nitrile content 36%, iodine value 28, ML _{1 + 4} (100 ° C.) 78] SRF carbon black 60 〃 stearic acid 1 〃 diphenylamine Anti-aging agent 1.5 〃 Imidazole anti-aging agent 1.5 〃 Dicumyl peroxide 4 〃 TiO ₂ (average particle size 0.3 μm) 10 〃 The above components are kneaded using a 3L kneader and an open roll, and the kneaded product is 170 Press vulcanization for 20 minutes at ℃ and 1
It was vulcanized and molded into a sheet of 150 × 150 × 2 mm by oven vulcanization at 60 ° C. for 3 hours.

Example 5 In Example 4, the amount of TiO ₂ was changed to 20 parts by weight.

Comparative Example 4 In Example 4, no TiO ₂ was used.

Comparative Examples 5 to 6 In Example 4, the same amount of ZnO (Comparative Example 5) or Cr ₂ O ₃ (Comparative Example 6) was used instead of TiO ₂ .

The vulcanized sheets obtained in Examples 4 to 5 and Comparative Examples 4 to 6 were measured and observed for normal physical properties, flon resistance and mold stain resistance in the same manner as described above. The results are shown in. Table 2 Item real -4 actual -5 ratio -4 ratio -5 ratio -6 normal physical properties] Hardness (JIS A) 76 77 76 77 77 Tensile strength (MPa) 31.0 30.9 31.4 32.0 30.4 Elongation (%) 300 310 300 290 300 [CFC resistance] CFC R12 No foaming No foaming No foaming No foaming CFC R134a 〃 〃 Foaming With foaming With foaming [Stain resistance] Number of shots (times)>11>11>11> 11 > 11

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-6-271705 (JP, A) JP-A-7-118447 (JP, A) JP-A-5-65369 (JP, A) JP-A-1- 275646 (JP, A) JP 5-230314 (JP, A) JP 5-271474 (JP, A) JP 2-91136 (JP, A) JP 7-258550 (JP, A) JP-A-63-218764 (JP, A) JP-A-2-170842 (JP, A) JP-A-4-76058 (JP, A) JP-A-5-148414 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08L 9/02 C08K 3/22 C08K 5/14

Claims (3)

(57) [Claims] 1. Per 100 parts by weight of hydrogenated nitrile rubber,
A hydrogenated nitrile rubber composition comprising about 20 to 180 parts by weight of a reinforcing agent or filler, about 0.5 to 100 parts by weight of Fe ₂ O ₃ and about 1 to 10 parts by weight of an organic peroxide. 2. Per 100 parts by weight of hydrogenated nitrile rubber,
A hydrogenated nitrile rubber composition comprising about 20 to 180 parts by weight of a reinforcing agent or filler, about 0.5 to 100 parts by weight of TiO ₂ and about 1 to 10 parts by weight of organic peroxide. 3. The hydrogenated nitrile rubber composition according to claim 1, which is used as a vulcanization molding material for a sealing material which is in contact with Freon R12 and Freon R134a.