JP2006199849A - Fluorine-containing elastomer composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluorine-containing elastomer composition without soiling a mold used for its peroxide cross-linking and the surface of a cross-linked molded article, and also excellent in mold-releasing property and metal corrosion resistance. <P>SOLUTION: This fluorine-containing elastomer composition is obtained by adding triethanol amine to a fluorine-containing elastomer capable of being cross-linked with the peroxide. The fluorine-containing elastomer composition does not soil the mold used for the peroxide cross-linking, and the surface of the molded article is not soiled since the added triethanol amine [N(CH<SB>2</SB>CH<SB>2</SB>OH)<SB>3</SB>] is not bled out. The effects of excellent mold releasing property and metal corrosion resistance are obtained by almost without damaging the normal state physical properties and compression set characteristics of the cross-linked article. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a fluorine-containing elastomer composition. More specifically, the present invention relates to a fluorine-containing elastomer composition that does not contaminate the mold used for peroxide crosslinking and the surface of the crosslinked molded article and is excellent in mold releasability and metal corrosion resistance.

  In recent years, various rubber products such as automobile rubber parts have been required to have high performance, and fluorine-containing elastomers are no exception. Various types of polymers and vulcanization systems have been developed to meet various demands for higher performance, but peroxide crosslinkable fluorine-containing elastomers are in demand for various applications due to their unique performance. Although it is stretched, there are problems with mold releasability and mold fouling during molding.

In order to improve mold releasability during molding of a peroxide-crosslinkable fluorine-containing elastomer, it has been proposed to add a primary higher alkylamine, as shown in the results of Comparative Examples 7 to 8 below. As described above, the mold release rate is not always satisfied, and the surface of the molded article that has undergone peroxide crosslinking is contaminated with bleed out.
Japanese Patent Laid-Open No. 6-322211

  An object of the present invention is to provide a fluorine-containing elastomer composition that does not contaminate the mold used for peroxide crosslinking and the surface of the crosslinked molded article, and is excellent in mold releasability and metal corrosion resistance. is there.

  The object of the present invention is achieved by a fluorine-containing elastomer composition in which triethanolamine is added to a peroxide-crosslinkable fluorine-containing elastomer.

The fluorine-containing elastomer composition according to the present invention does not stain the mold used for peroxide crosslinking, and the added triethanolamine N (CH ₂ CH ₂ OH) ₃ does not bleed out, so the surface of the molded product is soiled. In addition, the effects of excellent mold releasability and metal corrosion resistance can be obtained without substantially impairing the normal physical properties and compression set properties of the crosslinked molded product.

In contrast, ethanolamine NH ₂ CH ₂ CH ₂ OH and 1,8-diazabicyclo [5.4.0] undecene are unavoidable in mold releasability and compression set resistance, and primary higher alkyl amines The bleed-out is inevitable due to the compatibility with the fluorine-containing elastomer, and triisopropanolamine and triethylamine give only a result that the mold releasability and the compression set resistance are remarkably inferior.

The peroxide-crosslinkable fluorine-containing elastomer contains at least one fluorine-containing olefin such as vinylidene fluoride, hexafluoropropene, tetrafluoroethylene, perfluorovinyl ether, chlorotrifluoroethylene and the like, and contains bromine-containing and / or iodine-containing crosslinking points. It is obtained by polymerizing in the presence of a forming compound and 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] _1-4 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

  More specifically, copolymers of vinylidene fluoride and other fluorine-containing monomers, such as vinylidene fluoride-hexafluoropropene-tetrafluoroethylene terpolymer, vinylidene fluoride-hexafluproppropene copolymer Examples thereof include a polymer and a tetrafluoroethylene-perfluoro (alkyl vinyl ether) copolymer.

  Copolymers of tetrafluoroethylene [TFE] and perfluoro (alkyl vinyl ether) [FAVE] include TFE and perfluoro (methyl vinyl ether) [FMVE], perfluoro (ethyl vinyl ether) [FEVE], perfluoro (propyl). Vinyl ether) [FPVE] and the like, and a TFE-FMVE copolymer is preferably used. TFE and FAVE in these copolymers are a proportion of about 75-55 mol%, preferably about 70-65 mol% for the former and about 25-45 mol%, preferably about 30-35 mol% for the latter. It is desirable to use what is copolymerized with. Further, in the vinylidene fluoride [VdF] -hexafluoropropene [HFP] copolymer, VdF is about 65 to 85 mol%, preferably about 75 to 85 mol%, and HFP is about 35 to 15 mol%, It is preferable to use those copolymerized at a ratio of about 25 to 15 mol%. Furthermore, in the case of vinylidene fluoride [VdF] -hexafluoropropene [HFP] -tetrafluoroethylene [TFE] terpolymer, VdF is about 30 to 85 mol%, preferably about 40 to 80 mol%, It is preferable to use a copolymer in which HFP is copolymerized in an amount of about 5 to 50 mol%, preferably about 15 to 30 mol%, and TFE is about 0.1 to 35 mol%, preferably about 5 to 30 mol%.

In addition, examples of the bromine-containing and / or iodine compound used for forming a crosslinking point in the fluorine-containing elastomer include the following saturated or unsaturated compounds, and are described in Patent Document 2 below. Thus, an iodine-containing bromine compound represented by the general formula RBrnIm (R: fluorohydrocarbon group, chlorofluorohydrocarbon group or carbon hydrogen group, n, m: 1 or 2) can also be used.
CF ₂ = CFBr
CF ₂ = CFI
CF ₂ = CHBr
CF ₂ = CHI
CH ₂ = CHCF ₂ CF ₂ Br
CH 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)
Japanese Patent Publication No. 1-57125

  These bromine-containing and / or iodine compounds are contained in the fluorine-containing elastomer in a proportion of about 0.001 to 5% by weight, preferably about 0.01 to 3% by weight as Br atoms and / or I atoms. I atom is a polyfunctional compound formulated as a co-crosslinking agent (crosslinking aid) by radicals generated from organic peroxides during crosslinking of fluorine-containing elastomers. It is possible to efficiently form a crosslink by adding to the unsaturated compound. Moreover, since the crosslinking point is a CC bond, it is chemically more stable than the C = N bond of polyamine vulcanization or the CO bond of polyol vulcanization, and the rubber elasticity, heat resistance, chemical resistance, etc. of the crosslinked product are improved. It shows a tendency to improve.

  The copolymerization reaction of the fluorinated olefin in the presence of these bromine-containing and / or iodine crosslinking point-forming compounds is carried out by a solution in the presence of a polymerization initiator that is generally performed as described in Patent Document 2 above. It is carried out by a polymerization method, an emulsion polymerization method, a suspension polymerization method or the like.

  Such peroxide-crosslinkable fluorine-containing elastomer is added with about 0.1 to 5 parts by weight, preferably about 0.1 to 2 parts by weight of triethanolamine per 100 parts by weight thereof. When the addition ratio of triethanolamine is smaller than this, the surface of the mold used for the target peroxide of the present invention and the cross-linked molded product will not be stained, and the mold releasability and metal corrosion resistance will be improved. On the other hand, if it is used in a proportion higher than this, a decrease in physical properties cannot be avoided. Triethanolamine may be hydrochloride.

  The fluorine-containing elastomer is crosslinked by an organic peroxide. 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-di (tertiary butyl peroxy) Cyclododecane, 2,2-di (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) hex Sun, 1,1-di (tert-butylperoxy) -3,3,5-trimethylcyclohexane, n-butyl-4,4-di (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, etc. are used, preferably 2,5-dimethyl-2,5-di (tertiary butyl peroxy) hexane, 2,5-dimethyl-2,5-di (Benzoylperoxy) hexane and dicumyl peroxide are used in a proportion of about 0.1 to 10 parts by weight, preferably about 0.5 to 3 parts by weight, per 100 parts by weight of the fluorine-containing elastomer.

  When performing peroxide crosslinking, a polyfunctional unsaturated compound is used in combination as a co-crosslinking agent. When this co-crosslinking agent is used together with an organic peroxide, a vulcanized property is improved, and a fluororubber vulcanizate having excellent mechanical strength and compression set can be obtained. Examples of the polyfunctional unsaturated compound include tri (meth) allyl isocyanurate, tri (meth) allyl cyanurate, triallyl trimellitate, N, Nm-phenylene bismaleimide, diallyl phthalate, tris (diallylamine) -s- At least one of triazine, 1,2-polybutadiene, ethylene glycol diacrylate, diethylene glycol diacrylate, trimethylolpropane trimethacrylate and the like is about 10 parts by weight or less, preferably about 1 to 5 parts by weight per 100 parts by weight of the fluorine-containing elastomer. Used in proportions.

  In the composition comprising the above components, if necessary, other compounding agents, such as organic peroxide crosslinkable (co) polymers, processing aids, reinforcing agents, fillers, acid acceptors, Anti-aging agent, lubricant, plasticizer, pigment, perfluoropolyether, etc. are added, kneaded using roll, kneader, Banbury mixer, etc., then compression molding method, injection molding method according to generally used crosslinking conditions Vulcanization molding to gaskets, O-rings, packings, etc. is performed. Heating is generally performed by performing temporary vulcanization at a temperature of about 100 to 250 ° C. for about 1 to 120 minutes and then performing a two-time vulcanization at a temperature of about 150 to 300 ° C. for about 0 to 30 hours. Done. Examples of the organic peroxide-crosslinkable (co) polymer include fluorosilicone rubber, fluorophosphazene rubber, and fluororesin. Further, as perfluoropolyether, for example, perfluoro (polyethylene oxide), perfluoro (polypropylene oxide) may be added in an amount of 20 parts by weight or less, preferably 5 to 10 parts by weight with respect to 100 parts by weight of the fluorine-containing elastomer. it can.

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

Example 1
100 parts by weight of fluorine-containing elastomer A
MT carbon black (N990) 20 〃
Zinc flower 3 〃
2,5-dimethyl-2,5-di (tert-butylperoxy) hexane 3 3
(Japanese oil product Perhexa 25B-40; concentration 40%)
Triallyl isocyanurate 4 〃
(Nippon Kasei product Taiku M-60; concentration 60%)
Triethanolamine 1 〃
(Wako Pure Chemical Products)
As the fluorine-containing elastomer A, a charged composition of vinylidene fluoride [VdF] / hexaflupropane [HFP] / 1-iodo-2-bromotetrafluoroethane [IBrTFE] = 55 / 44.5 / 0.5 (% by weight) is usually used. A copolymer obtained by a copolymerization reaction at a polymerization rate of 90% or more was used.

  Each of the above components is kneaded using a 1 L kneader (manufactured by Moriyama) and an open roll, and the kneaded product is press-crosslinked to an O-ring and a sheet-like test piece at 180 ° C. for 10 minutes, and then secondary crosslinked at 200 ° C. for 6 hours. Went. While visually observing the presence or absence of bleed-out on the surface of the cross-linked molded product and the surface of the cross-linked molded product, mold releasability, metal corrosion resistance, normal physical properties and compression set were measured. Mold releasability is the same as above, using a mold that can integrally form a burr and an O-ring with a P6 O-ring of 10 P-24 and a burr thickness of 0.06 mm, without using an external release agent. Under the condition of press-crosslinking below, the operation of measuring whether or not the O-ring and the burr part can be released integrally is repeated 5 times, and the ratio (average value) of the O-ring remaining on the mold is taken as the release rate. This was used as a measure of mold releasability. The corrosion resistance of metal is less than 10% when the corrosion area ratio is 10% or more after measuring the corrosion area ratio after standing for 1 week under the condition of temperature 40 ℃ and humidity 80%. Was judged as having no corrosion.

Example 2
In Example 1, instead of fluorine-containing elastomer A, a charged composition of VdF / TFE (tetrafluoroethylene) /HFP/IBrTFE=23/14/62.5/0.5 (wt%), and polymerization of 90% or more by a conventional method The same amount of the fluorine-containing elastomer B copolymerized at a high rate was used.

Example 3
In Example 1, instead of the fluorine-containing elastomer A, a charged composition of VdF / TFE / FMVE (perfluoromethyl vinyl ether) /IBrTFE=51/11/37.5/0.5 (% by weight) was 90% or more by a conventional method. The same amount of fluorine-containing elastomer C copolymerized at a polymerization rate was used.

Example 4
In Example 1, instead of the fluorine-containing elastomer A, the fluorine-containing elastomer copolymerized by a conventional method with a charging composition of VdF / FMVE / IBrTFE = 26 / 73.5 / 0.5 (wt%) and a polymerization rate of 90% or more. The same amount of elastomer D was used.

Comparative Example 1
In Example 4, no triethanolamine was used.

Comparative Example 2
In Example 4, the same amount of ethanolamine (Wako Pure Chemical Industries, Ltd.) was used instead of triethanolamine.

Comparative Example 3
In Example 4, instead of triethanolamine, the same amount of triisopropanolamine (Kanto Chemical Co.) was used.

Comparative Example 4
In Example 4, the same amount of triethylamine (Wako Pure Chemical Industries, Ltd.) was used instead of triethanolamine.

Comparative Example 5
In Example 4, the same amount of pyridine (Wako Pure Chemical Industries, Ltd.) was used instead of triethanolamine.

Comparative Example 6
In Example 4, instead of triethanolamine, the same amount of 1,8-diazabicyclo [5.4.0] undecene (Sanapro product) was used.

Comparative Example 7
In Example 4, instead of triethanolamine, the same amount of octadecylamine (Akuso Chemicals product Armin 18D) was used.

Comparative Example 8
In Example 4, instead of triethanolamine, the same amount of trioctadecylamine (Akuzo Chemical product Armin DM-18D) was used.

The results obtained are shown in the following table.
table
Bleed Mold release Hardness Tensile strength Elongation Compression permanent Metal
Example Dirt out mold rate (%) (Point) (MPa) (%) Strain (%) Corrosive Example 1 None None 0 70 17.5 190 20 None
〃 2 〃 〃 0 71 18.6 210 22 〃
〃 3 〃 〃 0 66 16.9 180 27 〃
４ 4 〃 〃 0 70 19.5 220 22 〃
Comparative Example 1 〃 〃 100 69 18.9 210 20 Yes 〃 2 〃 〃 20 72 19.1 240 30 No 〃 3 〃 〃 80 70 16.9 190 30 〃
〃 4 〃 〃 100 73 16.5 260 41 〃
５ 5 〃 〃 90 71 17.9 200 27 〃
６ 6 〃 〃 30 73 20.1 180 29 〃
〃 7 Yes Yes 80 69 18.6 210 25 〃
〃 8 〃 〃 50 70 18.9 200 25 〃

The normal physical properties of hardness, tensile strength, and elongation are in accordance with JIS K6253, JIS K6251, and JIS K-6251, respectively, and compression set (25% compression, 200 ° C, 70 hours) is in accordance with JIS K6262. Each was measured in compliance.

Claims (3)

  A fluorine-containing elastomer composition comprising triethanolamine added to a peroxide-crosslinkable fluorine-containing elastomer.   The fluorine-containing elastomer composition according to claim 1, wherein 0.1 to 5 parts by weight of triethanolamine is added per 100 parts by weight of the fluorine-containing elastomer. The fluorine-containing elastomer composition according to claim 2, further comprising 10 parts by weight or less of a polyfunctional unsaturated compound co-crosslinking agent.