JP4345220B2 - Fluorine-containing elastomer composition - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fluorine-containing elastomer composition. More specifically, the present invention relates to a fluorine-containing elastomer composition suitably used as a molding material for a sealing material .
[0002]
[Prior art]
In recent years, various rubber products including automobile rubber parts have been required to have high performance. As for fluorine-containing elastomers, particularly those with peroxide cross-linking systems are growing in demand due to their unique performance. In peroxide cross-linking systems, co-crosslinking agents made of polyfunctional unsaturated compounds are generally used in combination. .
[0003]
However, such peroxide crosslinking a vulcanized article obtained by using the white considered also to be due to side reaction of the co-crosslinking agent, to a light yellow no observed many brown foreign matter failure, the production objectionable It ’s in a bad situation. Conventionally, in order to reduce such appearance defects, a method of reducing the use amount of the co-crosslinking agent has been taken, but this method is an important characteristic when used as a sealing material, particularly the physical properties of the vulcanized product. It worsens the compression set.
[0004]
[Problems to be solved by the invention]
An object of the present invention is a peroxide cross-linked fluorine-containing elastomer composition for molding a sealing material , which reduces physical properties of a vulcanizate even when a polyfunctional unsaturated compound co-crosslinking agent is used in combination. And to provide a device capable of reducing the appearance defect.
[0005]
[Means for Solving the Problems]
The object of the present invention is achieved by a fluorine-containing elastomer composition containing a peroxide -crosslinkable fluorine-containing elastomer, triallyl isocyanurate prepolymer , a polyfunctional unsaturated compound co-crosslinking agent and an organic peroxide.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Peroxide-crosslinkable fluorine-containing elastomer includes at least one fluorine-containing monomer such as vinylidene fluoride, hexafluoropropene, tetrafluoroethylene, perfluorovinyl ether, chlorotrifluoroethylene, or the like. It is obtained by polymerization in the presence of a compound or the like, and ethylene, propylene and the like can be further copolymerized there. Here, examples of the perfluorovinyl ether include the following compounds.
CF ₂ = CFOCF ₃
CF ₂ = CFOC ₂ F ₅
CF ₂ = CFOC ₃ F ₇
CF ₂ = CFO [CF ₂ CF (CF ₃ ) O] _{1 to 4} CF ₃
CF ₂ = CFO [CF ₂ CF (CF ₃ ) O] _{1 to 4} C ₃ F ₇
CF ₂ = CFO (CF ₂ ) _n OCF ₃
CF ₂ = CFOCF ₂ CF ₂ O (CF ₂ O) _n CF ₃
[0007]
Examples of the bromine-containing and / or iodine compound or nitrile-containing compound used for forming a crosslinking point in the fluorine-containing elastomer include the following saturated or unsaturated compounds.
CF ₂ = CFBr
CF ₂ = CFI
CF ₂ = CHBr
CF ₂ = CHI
C H ₂ = CHCF ₂ CF ₂ Br
C H ₂ = CHCF ₂ CF ₂ I
CF ₂ = CFOCF ₂ CF ₂ Br
CF ₂ = CFOCF ₂ CF ₂ I
CH ₂ = CHBr
CH ₂ = CHI
Br (CF ₂ ) ₄ Br
I (CF ₂ ) ₄ I
Br (CH ₂ ) ₂ (CF ₂ ) ₄ CH ₂ CH ₂ Br
I (CH ₂ ) ₂ (CF ₂ ) ₄ CH ₂ CH ₂ I
ICF ₂ CF ₂ Br
CF ₂ = CFO (CF ₂ ) _n OCF (CF ₃ ) CN (n: 1 to 10)
CF ₂ = CFO (CF ₂ ) _n CN (n: 1 to 10)
CF ₂ = CFO [CF ₂ CF (CF ₃ ) O] _m (CF ₂ ) _n CN (m: 1 to 10, n: 1 to 10)
[0008]
To such a peroxide-crosslinkable fluorine-containing elastomer, about 0.5 to 20 parts by weight, preferably about 1 to 10 parts by weight of triallyl isocyanurate prepolymer is added per 100 parts by weight thereof. As this prepolymer, those having a molecular weight of about 500 to 100,000, preferably about 5000 to 60,000 are used, and commercially available products having such a molecular weight range are used as they are. When the addition ratio is less than this, it is impossible to achieve the appearance of defects reduced, which is an object of the present invention, whereas above ratio, the physical properties of the formed molded article comes to deteriorate.
[0009]
Examples of the organic peroxide used as the crosslinking agent include tertiary butyl hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, p-menthane hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydro Peroxide, 2,5-dimethylhexane-2,5-dihydroperoxide, di-tert-butyl peroxide, dicumyl peroxide, tert-butyl cumyl peroxide, 1,1-bis (tert-butyl peroxy) Cyclododecane, 2,2-bis (tert-butylperoxy) octane, 1,1-ditert-butylperoxycyclohexane, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane, 2 , 5-Dimethyl-2,5-di (tert-butylperoxy) hexyne-3, 1,3-bis (tert-butylperoxyisopropyl) benzene, 2,5-dimethyl-2,5-di (benzoylper) (Oxy) Hexane, 1,1-bis (tert-butylperoxy) -3,3,5-trimethylcyclohexane, n-butyl-4,4-bis (tert-butylperoxy) valerate, benzoyl peroxide, m-toluylper Oxide, p-chlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, tertiary butyl peroxyisobutyrate, tertiary butyl peroxy-2-ethylhexanoate, tertiary butyl peroxybenzoate, tertiary butyl Peroxyisopropyl carbonate, tertiary butyl peroxyallyl carbonate, and the like are used at a ratio of about 0.1 to 10 parts by weight, preferably about 0.5 to 5 parts by weight, per 100 parts by weight of the fluorine-containing elastomer.
[0010]
When performing peroxide crosslinking, a polyfunctional unsaturated compound co-crosslinking agent is used in combination , such as diallyl phthalate, triallyl cyanurate, triallyl isocyanurate, trimethallyl isocyanurate, triallyl trimellitate, trimethylol. Propane trimethacrylate, ethylene glycol dimethacrylate, and the like are used at a ratio of about 10 parts by weight or less, preferably about 0.5 to 5 parts by weight, per 100 parts by weight of the fluorine-containing elastomer.
[0011]
In the composition comprising each of the above components, other compounding agents such as reinforcing agents, fillers, acid acceptors, anti-aging agents, lubricants, plasticizers, pigments, and the like are further added as necessary. After kneading with a closed kneader or the like, vulcanization molding is performed by a compression molding method, an injection molding method, or the like according to generally used crosslinking conditions.
[0012]
【The invention's effect】
In the fluorine-containing elastomer composition according to the present invention, even when a polyfunctional unsaturated compound co-crosslinking agent is used in combination, the appearance defect of the vulcanized molded product is remarkably reduced, and this adversely affects other physical properties. Very little effect. Therefore, this composition is effectively used as a molding material for sealing materials such as gaskets, O-rings and packings.
[0013]
【Example】
Next, the present invention will be described with reference to examples.
[0014]
Example 1
Vinylidene fluoride / hexafluoropropene / 1-iodo-2-bromotetrafluoroethane (charged weight ratio 55 / 44.5 / 0.5) copolymer [fluorinated elastomer A] 100 parts (weight, the same applies hereinafter), MT carbon black ( N990) 20 parts, organic peroxide (Japanese oil product perhexa 25B-40; 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane 40% content) 4 parts, triallyl isocyanurate ( 7 parts of Nippon Kasei Products Taiko M-60; 60% content) and 2 parts of triallyl isocyanurate prepolymer (Nippon Kasei products; molecular weight 5000-30000) were kneaded using a 1 L kneader and an open roll.
[0015]
The obtained kneaded product was subjected to press vulcanization at 180 ° C. for 10 minutes and secondary vulcanization at 200 ° C. for 6 hours to vulcanize and mold O-ring and sheet-like test pieces. For O-rings, appearance defects (counting the number of white, yellow, or brown foreign matter in four O-rings with an inner diameter of 20 mm, an outer diameter of 30 mm, and a wire diameter of 5 mm with a 20-fold magnifier) and compression set (JIS K-6262 compliant; 25% compression, 200 ° C, 70 hours) Measured for vulcanized sheet, hardness (JIS K-6253 compliant), tensile strength (JIS K-6251 compliant) and elongation (JIS JIS)
K-6251) was measured as a normal state physical property.
[0016]
Example 2
In Example 1, the amount of triallyl isocyanurate prepolymer was changed to 4 parts.
[0017]
Example 3
In Example 1, the amount of triallyl isocyanurate prepolymer was changed to 6 parts.
[0018]
Example 4
In Example 1, in place of MT carbon black, 10 parts of a hydrous silica-based reinforcing agent (Shionogi Pharmaceutical White Carbon Carplex 1120) and 5 parts of titanium oxide (Ishihara Sangyo Products Type A-100) were used.
[0019]
Example 5
In Example 2, 10 parts of a hydrous silica reinforcing agent (Carplex 1120) and 5 parts of titanium oxide (Typaque A-100) were used in place of MT carbon black.
[0020]
Example 6
In Example 3, 10 parts of a hydrous silica-based reinforcing agent (Carplex 1120) and 5 parts of titanium oxide (Typaque A-100) were used instead of MT carbon black.
[0021]
Example 7
In Example 5, instead of the fluorinated elastomer A, the same amount of vinylidene fluoride / tetrafluoroethylene / hexafluoropropene / 1-iodo-2-bromotetrafluoroethane (charged weight ratio 23/14 / 62.5 / 0.5) A copolymer [fluorinated elastomer B] was used.
[0022]
Example 8
In Example 5, instead of the fluorinated elastomer A, the same amount of vinylidene fluoride / tetrafluoroethylene / perfluoro (methyl vinyl ether) / 1-iodo-2-bromotetrafluoroethane (feed weight ratio 51/11 / 37.5 /0.5) copolymer [fluorinated elastomer C] was used, and the amount of organic peroxide (Perhexa 25B-40) and triallyl isocyanurate (Tyke M-60) were each changed to 2 parts.
[0023]
Example 9
In Example 5, instead of fluorine-containing elastomer A, the same amount of tetrafluoroethylene / perfluoro (methyl vinyl ether) / 1-iodo-2-bromotetrafluoroethane (feed weight ratio 26 / 73.5 / 0.5) copolymer [Fluorine-containing elastomer D] was used, and the amount of organic peroxide (Perhexa 25B-40) was changed to 2 parts, and the amount of triallyl isocyanurate (Tyke M-60) was changed to 4 parts.
[0024]
Comparative Example 1
In Example 1 in which the fluorinated elastomer A was used, the triallyl isocyanurate prepolymer was not used.
[0025]
Comparative Example 2
In Example 4 in which the fluorine-containing elastomer A was used, the triallyl isocyanurate prepolymer was not used.
[0026]
Comparative Example 3
In Example 7 in which the fluorinated elastomer B was used, the triallyl isocyanurate prepolymer was not used.
[0027]
Comparative Example 4
In Example 8 in which the fluorinated elastomer C was used, the triallyl isocyanurate prepolymer was not used.
[0028]
Comparative Example 5
In Example 9 in which the fluorine-containing elastomer D was used, the triallyl isocyanurate prepolymer was not used.
[0029]
The measurement results in the above examples and comparative examples are shown in the following table.

Claims (3)

A fluorine-containing elastomer composition for molding a sealing material, comprising a fluorine-containing elastomer capable of peroxide crosslinking, a triallyl isocyanurate prepolymer , a polyfunctional unsaturated compound co-crosslinking agent and an organic peroxide. The fluorine-containing elastomer composition according to claim 1, wherein a triallyl isocyanurate prepolymer having a molecular weight of 500 to 100,000 is used. A sealing material vulcanized and molded from the fluorine-containing elastomer composition according to claim 1.