JP3508431B2 - Fluoro rubber composition - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a fluororubber composition. More specifically, it relates to a fluororubber composition effectively used as a vulcanization molding material for a seal ring for FFV fuel oil.

[0002]

2. Description of the Related Art FFV (Flexible Fuel Vehic) in which alcohol, methyl tert-butyl ether, etc. are added to gasoline in order to improve the efficiency of fuel for automobiles and comply with exhaust gas regulations
le) fuel oil has come to be used, and along with this, there is an increasing tendency to use fluororubber having fuel oil resistance as a sealing material.

The composition of fuel oil for FFV depends on the manufacturer,
Materials that are compatible with FFV fuel oil require various properties such as fuel oil swelling resistance, heat resistance and low temperature balance, amine crack resistance, metal corrosion resistance, etc. There is.

In the conventionally used fluororubber, since the FFV fuel oil component is not constant as described above, various problems have been observed. In particular, when the content of alcohol-based substances is high, there is a problem that the metal, which is the piping member, is exposed to high temperature conditions, causing corrosion at the rubber contact part, and high temperature such as fuel injectors.・ When used under high pressure,
Problems such as destruction of the seal rubber due to swelling were observed.

[0005]

The object of the present invention is to provide an FF.
A fluororubber composition which is suitably used as a vulcanization molding material for a V fuel oil seal ring, and can give a seal ring excellent in fuel oil swelling resistance, low temperature resistance, amine crack resistance, metal corrosion resistance and the like. To provide.

[0006]

The object of the present invention is as follows.
Vinylidene fluoride with a fluorine content of 66% or more-perfluoro
(Methyl vinyl ether) -tetrafluoroethylene terpolymer, liquid fluororubber, iodine adsorption amount 40 ~ 100mg / g
It is achieved by fluorine rubber composition containing the hydrotalcite / calcium hydroxide mixture of carbon black and the weight mixing ratio of 40 / 60-95 / 5.

[0007]

DETAILED DESCRIPTION OF THE INVENTION Vinylidene fluoride-perfluoro
The (methyl vinyl ether) -tetrafluoroethylene terpolymer (hereinafter simply referred to as fluororubber) has a fluorine content of 66% or more, preferably 66 to 68%, and a Mooney viscosity ML _{1 + 10} ( 100 ° C) is about 30-100, preferably about 35-
70's are used. This terpolymer has an excellent balance between swelling resistance to swelling fuel oils such as alcohol, heat resistance and low temperature resistance, and also has excellent amine crack resistance. In order to achieve this, the above fluorine content is required. actually,
Commercially available products such as those manufactured by DuPont Viton G series can be used.

The liquid fluororubber includes vinylidene fluoride-hexafluoropropene copolymer, vinylidene fluoride-hexafluoropropene-tetrafluoroethylene terpolymer, etc., and its viscosity (100 ° C.) is about 500. ~ 30
00 cps, preferably about 550 to 2000 cps, is used in a ratio of about 1 to 20 parts by weight, preferably about 4 to 10 parts by weight, per 100 parts by weight of fluororubber. When the liquid fluororubber is reinforced with carbon black, the processability and low-temperature property are deteriorated. On the other hand, the liquid fluororubber is blended and used in the above proportions in order to prevent it.

Carbon black has an iodine adsorption amount of about 40 to 100 mg / g (DBP oil absorption amount of about 80 to 150 ml / 100).
g), preferably about 45 to 85 mg / g (about 90 to 140 ml / 100 g), is used in a ratio of about 5 to 40 parts by weight, preferably about 7 to 25 parts by weight per 100 parts by weight of fluororubber. . As the carbon black having such an iodine adsorption amount, specifically,
N320 to N550 reinforcing carbon black is used. When carbon black other than this, for example, carbon black having an iodine adsorption amount larger than this, in other words, carbon black having a smaller particle size, is used, dispersibility in rubber,
This is not preferable because problems such as scorch will occur.

The hydrotalcite / calcium hydroxide mixture is used in a weight ratio of about 40/60 to 95/5, preferably about 60/40.
The mixture of 90/10 is used as an antacid in an amount of about 3 to 20 parts by weight, preferably about 5 to 15 parts by weight, per 100 parts by weight of fluororubber. Hydrotalcite Mg _4.5 Al ₂
(OH) ₁₃ CO ₃ · 3.5H ₂ O and calcium hydroxide are uniformly mixed and used in a dry type mixer such as a Henschel mixer.

The fuel oil for FFV used in the market contains about 10 to 90% of alcohol such as methanol and ethanol in addition to the gasoline component which is the base oil. In place of the above, a rubber swelling component such as methyl tert-butyl ether may be contained in an amount of about 5 to 30% as an exhaust gas countermeasure. In addition, metal corrosive components including acidic substances called "Aggressive" components are present in the fuel oil, which is considered to be the cause of rust formation at the rubber-metal contact.

The hydrotalcite / calcium hydroxide mixture absorbs the corrosive component generated from the aggressive component in the fuel oil inside the rubber, and prevents the metal-rubber cell action due to the corrosive component to prevent metal Prevents accelerated corrosion. It has also been found that hydrotalcite and calcium hydroxide are more effective in preventing corrosion when they are uniformly mixed by premixing and then kneaded into rubber, rather than kneading each into rubber.

For the preparation of the fluororubber composition containing the above-mentioned respective components as essential components, other necessary compounding agents such as vulcanizing agents such as organic peroxides and co-crosslinking agents which are polyfunctional unsaturated compounds are used. , Vulcanization accelerator, processing aids, etc.
It is carried out by kneading for a predetermined time using a kneading machine such as a Banbury mixer.After kneading and discharging, the kneaded product is rolled out into sheets or cut into dough of any shape, then a compression molding machine, a transfer molding machine, etc. The vulcanization molding is performed according to the usual vulcanization molding conditions, and is vulcanized into a seal ring shape.

[0014]

EFFECTS OF THE INVENTION The fluororubber composition according to the present invention can give a vulcanized molded article excellent in fuel oil swelling resistance, low temperature resistance, amine crack resistance, metal corrosion resistance and the like. It is preferably used as a vulcanization molding material for seal rings used for injectors, piping connectors and the like.

The vulcanized seal ring is used in a bad environment for rubber, and even if it is used at high temperature and high pressure like a fuel oil injector, the seal rubber is not damaged, and moreover, it is resistant to Aggressive Fuel.
providing a sealing rubber material having material properties of high strength with superior l property.

[0016]

EXAMPLES Next, the effects of the present invention will be described with reference to examples.

EXAMPLES The following components were used. (1) Vinylidene fluoride-perfluoro (methyl vinyl ether) -tetrafluoroethylene terpolymer ・ Viton GFLT (DuPont product) Fluorine content 67% ML _{1 + 10} (100 ℃) 90 ・ Viton G301 (DuPont company) Product) Fluorine content 66% ML _{1 + 10} (100 ℃) 30 ・ Viton G501 (Dupont product) Fluorine content 66% ML _{1 + 10} (100 ℃) 50 ・ Viton G505 (Dupont product) Fluorine content 65 % ML _{1 + 10} (100 ℃) 50 ・ Viton GF (Dupont product) Fluorine content 70% However, vinylidene fluoride-hexafluoropropene-tetrafluoroethylene terpolymer ・ Viton E60C (Dupont product) Fluorine Content 66% However, vinylidene fluoride-hexafluoropropene copolymer (2) Liquid fluororubber ・ Viton LM (Dupont product) Viscosity (100 ℃) 2000cps ・ Daikin G101 (Daikin product) Viscosity (100 ℃) 1200cps ( 3) Carbon black N330 (Showa Ki Bot products Show Black N330) Iodine adsorption amount 80mg / g ・ N340 (Mitsubishi Chemical product Diablack SH) Iodine adsorption amount 95mg / g ・ N550 (Cabot's product Sterling SO) Iodine adsorption amount 45mg / g ・ N326 (Colombian Neotex) N326) Iodine adsorption amount 85 mg / g ・ N990 (MT carbon black) Iodine adsorption amount 20 mg / g (4) Hydrotalcite / calcium hydroxide mixture ・ Hydrotalcite (Kyowa Chemical DHT-4A) ・ Calcium hydroxide (Shiroishi (Calcium products) (5) Other compounding agents, triallyl isocyanurate (Nippon Kasei Product Tayk M-6
0,60%) ・ 2,5-Dimethyl-2,5-di-tert-butylperoxyhexane
(Nippon Oil and Fat Products Perhexa 25B-40, 40%)-Dicumyl peroxide (Nippon Oil and Fat Products Perkmill D) -1,3-Di-tert-butyl peroxyisopropylbenzene (Nippon Oil and Fat Products Peroximon F-40) -Aliphatic Wax (Dupont product VPA No.3) -Sodium stearate (Kao product NS soap) -Methylenebis stearamide (Armor product Armowax) -Aluminum silicate (clay) -Barium sulfate (Sakai Chemical product blank fix) -Calcium carbonate (Shiroishi calcium product) ・ Magnesium oxide (Kyowa Chemical product)

After kneading each compounding component excluding the vulcanizing agent in each of Examples and Comparative Examples described below with a 1 L kneader, a vulcanizing agent was added to form a rubber sheet, and 170 ° C. for 10 minutes (Example 3, Comparative Example 3 At 165 ° C for 15 minutes), press vulcanization (primary vulcanization) and 200
℃, 24 hours oven vulcanization (secondary vulcanization), 150 × 150
A × 2 mm slab sheet was vulcanized and molded. At the same time, 3.0 mm diameter O-rings for compression set tests were vulcanized and molded.

The vulcanized molded product thus obtained was measured or evaluated for the following items. Vulcanization properties: JIS K-6301 compliant compression set: 150 ° C., 70 hours Fuel oil resistance (1): Fuel oil C at 100 ° C. [isooctane / toluene (volume ratio 50:50) mixture] -methanol (80:20) ) Measurement of hardness change and volume change rate after immersion in mixed solution for 120 hours Fuel oil resistance (2): Fuel oil at 100 ° C. Immersed in C-methyl tert-butyl ether (80:20) mixed solution for 120 hours The change in hardness and the rate of change in volume were measured. Fuel oil resistance (3): Change in hardness after 120 hours of immersion in a mixed liquid of fuel oil C-ethylenediamine (95.5: 0.5) at 100 ° C. and While measuring the volume change rate, bend the rubber sheet sample by 180 degrees by hand and visually observe the presence of cracks on the rubber surface. Fuel oil resistance (4): Fuel oil C-methanol (80:20) mixed solution at 100 ° C 2% Aggre-ssiv
e solution (water-Na ₂ SO ₄ -HCl) was added, the hardness change and volume change rate after immersion for 120 hours were measured, and rubber was sandwiched between metals (SPCC) to obtain a test solution at 100 ° C. After immersing in 150 ml for 120 hours, take out the sample and visually observe the presence of rust on the metal surface. Fuel oil resistance (5): For alcohol fuel (gasoline procured in Brazil), the same measurement and observation as above (4) Fuel oil resistance (6): The alcohol fuel (gasoline procured in the United States) was measured and observed in the same manner as in (4) above. Low temperature characteristics: TR-10 value was measured.

Example 1 100 parts by weight of terpolymer (Viton G301) Liquid fluororubber (Viton LM) 2 〃 N330 carbon black 20 〃 Hydrotalcite / Ca (OH) ₂ (weight ratio 70:30) mixture 8 〃 Sodium stearate (NS soap) 1 〃 Aliphatic wax (VPA No.3) 1 〃 Methylenebis stearamide (armowax) 0.5 〃 Triallyl isocyanurate (Tyke M-60) 6 〃 Organic peroxide (Park mill) D) 2〃

Example 2 100 parts by weight of terpolymer (Viton G501) Liquid fluororubber (Viton LM) 5 〃 N326 carbon black 25 〃 Hydrotalcite / Ca (OH) ₂ (weight ratio 90:10) mixture 7 〃 Aliphatic wax (VPA No.3) 1 〃 Methylenebis stearamide (armowax) 2 〃 Triallyl isocyanurate (Tyke M-60) 6 〃 Organic peroxide (Perhexa 25B-60) 5 〃

Example 3 80 parts by weight of terpolymer (Viton GFLT) 〃 (Viton G301) 20 〃 Liquid fluororubber (G101) 4 〃 N550 carbon black 28 〃 Hydrotalcite / Ca (OH) ₂ (weight ratio 70:30) Mixture 10 〃 Sodium stearate (NS soap) 2 〃 Methylene bis stearamide (armowax) 1 〃 Triallyl isocyanurate (Tyke M-60) 6 〃 Organic peroxide (Peroximon F-40) 6 〃

Example 4 50 parts by weight of terpolymer (Viton G501) 〃 (Viton G301) 50 〃 Liquid fluororubber (G101) 2 〃 N347 carbon black 12 〃 Hydrotalcite / Ca (OH) ₂ (weight ratio 90:10) Mixture 6 〃 Sodium stearate (NS soap) 1 〃 Aliphatic wax (VPA No.3) 1 〃 Methylenebis stearamide (armowax) 1 〃 Triallyl isocyanurate (Tyke M-60) 7 〃 Organic peroxide (Park Mill D) 3〃

Comparative Example 1 100 parts by weight of terpolymer (Viton G505) Liquid fluororubber (Viton LM) 2 〃 N330 carbon black 20 〃 Hydrotalcite / Ca (OH) ₂ (weight ratio 70:30) mixture 1 〃 Sodium stearate (NS soap) 1 〃 Aliphatic wax (VPA No.3) 1 〃 Methylenebis stearamide (armowax) 0.5 〃 Triallyl isocyanurate (Tyke M-60) 6 〃 Organic peroxide (Park mill) D) 2〃

Comparative Example 2     100 parts by weight of terpolymer (Viton GF)     Liquid fluororubber (Viton LM) 5 〃     N326 Carbon Black 25〃     Aliphatic wax (VPA No.3) 1 〃     Methylenebis stearamide (armowax) 2〃     Triallyl isocyanurate (Tyke M-60) 6 〃     Organic peroxide (Perhexa 25B-40) 5〃

Comparative Example 3 Binary copolymer (Viton E60C) 100 parts by weight Liquid fluororubber (Viton LM) 2〃 N326 carbon black 20〃 MgO / Ca (OH) ₂ mixture 3 / 5〃 Aliphatic wax (VPA No) .3) 1 〃 methylene bis stearamide (armowax) 0.5 〃

Comparative Example 4 50 parts by weight of terpolymer (Viton G501) 〃 (Viton G301) 50 〃 Liquid fluororubber (G101) 2 〃 MT carbon black 12 〃 Hydrotalcite / Ca (OH) ₂ (weight ratio 90:10) Mixture 1.5 〃 Sodium stearate (NS soap) 1 〃 Aliphatic wax (VPA No.3) 1 〃 Methylenebis stearamide (armowax) 1 〃 Triallyl isocyanurate (Tyke M-60) 7 〃 Organic peroxide (Park Mill D) 3〃

Comparative Example 5     80 parts by weight of terpolymer (Viton GFLT)          〃 (Viton G301) 20 〃     Liquid fluororubber (G101) 4 〃     Aluminum silicate (clay) 10〃     Barium Sulfate (Blank Fix) 20〃     Calcium carbonate 10〃     Sodium stearate (NS soap) 2〃     Methylenebis stearamide (Armorax) 1 〃     Triallyl isocyanurate (Tyke M-60) 6 〃     Organic peroxide (Peroximon F-40) 6 〃

Comparative Example 6 100 parts by weight of terpolymer (Viton GFLT) N330 carbon black 15 〃 barium sulfate (blank fix) 10 〃 calcium carbonate 5 〃 hydrotalcite / Ca (OH) ₂ (weight ratio 70:30 ) Mixture 2 〃 Sodium stearate (NS soap) 1 〃 Aliphatic wax (VPA No.3) 1 〃 Methylenebis stearamide (armowax) 0.5 〃 Triallyl isocyanurate (Tyke M-60) 6 〃 Organic peroxide Thing (Park Mill D) 2 〃

Comparative Example 7 100 parts by weight of terpolymer (Viton G301) Liquid fluororubber (Viton LM) 2 〃 N330 carbon black 20 〃 Hydrotalcite / Ca (OH) ₂ (weight ratio 10:90) mixture 8 〃 Sodium stearate (NS soap) 1 〃 Aliphatic wax (VPA No.3) 1 〃 Methylenebis stearamide (armowax) 0.5 〃 Triallyl isocyanurate (Tyke M-60) 6 〃 Organic peroxide (Park mill) D) 2〃

The results obtained are shown in the following table. Table Example Comparative Example Measurement items 1 2 3 4 1 2 3 4 5 6 7 [Normal physical properties] Hardness (JIS A) (Point) 78 81 85 72 75 82 80 70 72 75 78 Tensile strength (MPa) 19.2 20.2 21.2 18.1 16.9 21.0 15.3 11.0 10.6 18.3 19.7 Elongation at break (%) 210 190 180 190 210 170 200 160 230 190 220 [Compression set] 150 ℃, 70 hours (%) 25 24 26 23 27 40 14 24 44 28 24 [Fuel oil resistance (1)] Hardness change (point) -14 -12 -13 -16 -22 -12 -21 -15 -14 -12 -13 Volume change rate (%) +26 +23 +24 +27 +48 +15 +45 +26 +26 +24 +26 [Fuel oil resistance (2)] Hardness change (points) -10 -9 -10 -10 -19 -8 -18 -10 -11 -9 -10 Volume change rate (%) +16 +14 +16 +17 +40 +12 +39 +16 +17 +15 +15 [Fuel oil resistance (3)] Hardness change (points) -8 -7 -8 -8 -16 -10 -15 -9 -8 -8 -8 Volume change rate (%) +12 +10 +11 +12 +24 +9 +22 +13 +8 +11 +12 180 ° Bending test None None None None None No Yes Yes Yes No No No No None [Fuel oil resistance (4)] Hardness change (points) -13 -12 -12 -14 -21 -12 -20 -13 -14 -14 -13 Volume change rate (%) +25 +23 +26 +25 +47 +16 +46 +24 +26 +24 +24 Metal corrosion No No No No No No Yes Yes Yes Yes Yes Yes Yes [Fuel oil resistance (5) ] Hardness change (point) -11 -10 -11 -11 -17 -9 -16 -11 -12 -10 -12 Volume change rate (%) +18 +15 +10 +12 +23 +8 +22 + 10 +16 +16 +18 Metal corrosion No No No No Yes Yes Yes Yes Yes Yes Yes [Fuel oil resistance (6)] Hardness change (points) -9 -7 -8 -9 -16 -10 -15 -8 -9 -9 -9 Volume change rate (%) +13 +12 +13 +14 +24 +7 +22 +14 +13 +12 +13 Metal corrosion No No No No No Yes Yes Yes Yes Yes Yes Yes [Low temperature characteristics ] TR-10 (℃) -26 -27 -25 -26 -29 -6 -16 -26 -24 -25 -25

From the above results, the following can be said. (1) The vulcanized molded products obtained in the respective examples have high strength physical properties in which FFV fuel oil resistance and cold resistance are well balanced, and metal corrosion is not observed. (2) In Comparative Example 1 having a lower fluorine content and a smaller blending amount of the hydrotalcite / Ca (OH) ₂ mixture as compared with Example 1,
FFV fuel oil resistance is poor and metal corrosion is also observed. (3) In Comparative Example 2 in which another terpolymer having a higher fluorine content than that in Example 2 was used, but no antacid was used, low temperature characteristics and amine resistance were poor, Metal corrosion is also seen. (4) In Comparative Example 3 in which a binary copolymer different from that in Example 1 was used and other antacid mixture was used, FF resistance was improved.
V Fuel oil resistance and amine resistance are poor, and metal corrosion is also observed. (5) In Comparative Example 4 in which MT carbon black was used as compared with Example 4, the strength was low and metal corrosiveness was also observed. (6) In Comparative Example 5, in which a reinforcing agent different from that in Example 3 was used, the strength was low, the compression set was large, and the metal corrosiveness was also observed. (7) In Comparative Example 6 in which the liquid fluororubber was not used as compared with Example 1, workability was poor and metal corrosiveness was also observed. (8) In Comparative Example 7 in which the mixing ratio of the hydrotalcite / Ca (OH) ₂ mixture was changed as compared with Example 1, the physical properties were good, but metal corrosion was present.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI C08L 27/18 C08L 27/18 29/10 29/10 (56) Reference JP-A-6-116464 (JP, A) JP JP-A-6-293850 (JP, A) JP-A-8-272208 (JP, A) JP-A-62-277456 (JP, A) JP-A-59-22943 (JP, A) JP-A-6-331040 (JP , A) JP-A-2-191644 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08L 27/12-27/20 C08L 29/10

Claims (2)

(57) [Claims] 1. A vinylidene fluoride-perfluoro (methyl vinyl ether) -tetrafluoroethylene terpolymer having a fluorine content of 66% or more, a liquid fluororubber, a carbon black having an iodine adsorption amount of 40 to 100 mg / g, and a weight mixture. Ratio 40 /
A fluororubber composition comprising a hydrotalcite / calcium hydroxide mixture of 60 to 95/5. 2. The fluororubber composition according to claim 1, which is used as a vulcanization molding material for a seal ring for FFV fuel oil.