JP2834504B2 - Novel quaternary benzimidazole salt and crosslinkable fluorine-containing elastomer composition containing the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a novel quaternary benzimidazole salt and a crosslinkable fluorine-containing elastomer composition containing the same. More specifically, the present invention relates to a novel quaternary benzimidazole salt used as an additive for a fluorine-containing elastomer containing iodine and / or bromine in a molecule, and a crosslinkable fluorine-containing elastomer composition containing the same.

[Conventional technology]

The organic peroxide crosslinking of the fluorinated elastomer is considered to be superior to conventional crosslinking methods such as polyol crosslinking and polyamine crosslinking because it gives a crosslinked product having excellent engine oil resistance and solvent resistance.

As a fluorine-containing elastomer crosslinked by an organic peroxide, one containing iodine and bromine, iodine or bromine in the molecule has been proposed by the present applicant and others (Japanese Patent Application No. 62-58145, No. 62-232,407, No. 53-125,491, No. 60-221,409, No. 59
JP-A-20,310, JP-A-62-260,807, JP-B-54-158
No. 5, etc.).

However, the organic peroxide used in this crosslinking generates toxic substances such as methyl iodide (CH ₃ I) or methyl bromide (CH ₃ Br) derived from the methyl group in the molecule upon decomposition. This is a problem that cannot be ignored in terms of maintaining the workplace and surrounding environment.

[Problems to be Solved by the Invention] One object of the present invention is to provide a method for crosslinking CH ₃ generated during decomposition of an organic peroxide during crosslinking of an iodine and / or bromine-containing fluorine-containing elastomer which is cross-linked by an organic peroxide. I or CH
An object of the present invention is to provide a novel additive that significantly reduces the amount of ₃ Br generated.

Another object of the present invention is to provide a crosslinkable composition of an iodine and / or bromine-containing fluoroelastomer containing such a novel additive.

[Means for solving the problem]

The novel additive that achieves the object of the present invention is:
The following two types of compounds.

1-aralkyl or 1-alkyl-4-piperidinopyridinium benzimidazole-2-thioate 5-aralkyl or 5-alkyl-1,5-diazabicyclo [4,3,0] nonanium benzimidazole-2
-Thioate In these formulas, R is an alkyl group having 1 to 24 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, and the compound of the above formula [I] is preferably a 4-piperidinopyridinium halide having a benzyl group at the 1-position. 2
-An alkali metal salt of mecaptobenzimidazole is separately dissolved in a polar solvent (soluble solvent such as water, alcohol, ketone, ester, amide, ether, etc.), and each of these solutions is added to about -20 to It can be easily produced by stirring and mixing at + 40 ° C., generally at room temperature.

Further, the compound of the above formula [II] may be a compound of the known 5-aralkyl or 5-aryl-substituted, preferably 5-benzyl-substituted 1,5-diazabicyclo [4,3,0] nonanium halide and 2-mercaptobenzimidazole. Can be easily produced by the same reaction method as described above using the above-mentioned alkali metal salt.

The quaternary benzimidazole thus obtained
The 2-thioate compound [I] or [II] is an iodine and / or bromine-containing fluorine-containing elastomer 10
It is used in an amount of about 0.1 to 5 parts by weight, preferably about 0.5 to 3 parts by weight per 0 parts by weight, and forms a crosslinkable fluoroelastomer composition together with an organic peroxide.

As the fluorine-containing olefin constituting the main part of the fluorine-containing elastomer containing iodine and / or bromine in the molecule used in the present invention, those having 2 to 8 carbon atoms are preferably used, for example, vinylidene fluoride, Tetrafluoroethylene, hexafluoropropene, pentafluoropropene, chlorotrifluoroethylene, methyl perfluorovinyl ether, ethyl perfluorovinyl ether, n- or isopropyl perfluorovinyl ether, n-, iso- or tert-butyl perfluorovinyl ether , N- or iso-amyl perfluorovinyl ether, perfluoro (methyl vinyl ether), perfluoro (ethyl vinyl ether), perfluoro (n- or iso-propyl vinyl ether), perfluoro (n , Iso- or tertiary butyl vinyl ether), perfluoro (n- or iso-amyl vinyl ether), perfluoro (propoxypropyl vinyl ether) and the like. Ethylene, perfluorocyclobutene, perfluoro (methylcyclopropene), hexafluoroisobutene, 1,2,
2-trifluorostyrene, perfluorostyrene and the like are also used.

These fluorinated olefins can also be used in the form of being copolymerized with an olefinic compound having 2 to 6 carbon atoms and / or a fluorinated diene having 4 to 8 carbon atoms.

Examples of the olefinic compound include those having 2 to 6 carbon atoms such as ethylene, propylene, butene, unsaturated vinyl esters such as vinyl acetate, and alkyl vinyl ethers such as methyl vinyl ether and ethyl vinyl ether. Copolymerize at a rate of 50 mol%.

Further, as the fluorine-containing diene, for example, perfluoro-1,3-butadiene, perfluoro-1,4-pentadiene, 1,1,2-trifluoro-1,3-butadiene, 1,1,2-
Trifluoro-1,4-pentadiene, 1,1,2,3,3-pentafluoro-1,4-pentadiene, perfluoro-1,7-octanediene, perfluorodivinyl ether, perfluorovinyl perfluoroallyl ether , Vinyl perfluoro allyl ether, perfluoro vinyl vinyl ether and the like having 4 to 8 carbon atoms. These fluorinated dienes are preferably copolymerized so as to be present in the fluorinated elastomer at a ratio of about 1 mol% or less. When copolymerization is carried out in a large proportion, gelling of the copolymer elastomer becomes remarkable, and processability (flow characteristics) and elongation of the vulcanized product deteriorate.

Specific fluorinated olefin copolymers include hexafluoropropene-vinylidene fluoride copolymer, hexafluoropropene-vinylidene fluoride-tetrafluoroethylene terpolymer, and tetrafluoroethylene-vinylidene fluoride-perfluorocopolymer. (Methyl vinyl ether) terpolymer, tetrafluoroethylene-vinylidene fluoride-perfluoro (propyl vinyl ether) 3
Copolymer, tetrafluoroethylene-perfluoro (propoxypropyl vinyl ether) copolymer, tetrafluoroethylene-perfluoro (methyl vinyl ether) copolymer, tetrafluoroethylene-propylene copolymer, tetrafluoroethylene-vinylidene fluoride -Hexafluoropropene-pentafluoropropene 4
Terpolymer, tetrafluoroethylene-hexafluoropropene-vinylidene fluoride-perfluoro (methyl vinyl ether) quaternary copolymer, tetrafluoroethylene-hexafluoropropene-hexafluoroisobutene terpolymer, tetrafluoroethylene- Cyclohexyl vinyl ether copolymer, hexafluoropropene
Vinylidene fluoride-chlorotrifluoroethylene terpolymer, vinylidene fluoride-tetrafluoroethylene-
Methyl perfluorovinyl ether terpolymer, vinylidene fluoride-tetrafluoroethyl-n-butyl perfluorovinyl ether terpolymer, vinylidene fluoride-methyl perfluorovinyl ether-perfluoro (methyl vinyl ether) terpolymer Terpolymer, tetrafluoroethylene-methyl perfluorovinyl ether-perfluoro (methyl vinyl ether) terpolymer, vinylidene fluoride-hexafluoropropene-tetrafluoroethylene-methyl perfluorovinyl ether quaternary copolymer, tetrafluoroethylene-n- Butyl perfluorovinyl ether-perfluoro (methyl vinyl ether) terpolymer, vinylidene fluoride-n-butyl perfluorovinyl ether copolymer, tetrafluoroethylene-propylene -n- butyl perfluorovinyl ether terpolymer, tetrafluoroethylene - vinylidene fluoride - propylene -n- butyl perfluorovinyl ether quaternary copolymer and the like.

The polymerization reaction is carried out by solution polymerization, suspension polymerization or emulsion polymerization of a fluorine-containing olefin or the above-mentioned comonomer and the above-mentioned comonomer by a conventionally known method.

When an iodine-containing odor compound, an iodine-containing compound or a bromine-containing compound is allowed to coexist during this polymerization reaction, iodine and / or bromine are introduced into the fluorinated olefin copolymer, and the crosslinking point at the time of organic peroxide crosslinking. To form

As the iodine-containing bromine compound, a saturated or unsaturated compound represented by the general formula RBrnIm (R: fluorohydrocarbon group, chlorofluorohydrocarbon group, chlorohydrocarbon group or hydrocarbon group, n, m: 1 or 2) A chain or aromatic compound in which n and m are each 1 is preferably used. Examples of the linear iodine-containing bromine compound include 1-bromo-2-iodoperfluoroethane, 1-bromo-3-iodoperfluoropropane, and 1-bromo-4.
-Iodoperfluorobutane, 2-bromo-3-iodoperfluorobutane, 3,4-dibromo-1-iodo-1,
1,2,2,4,4-hexafluorobutane, 3-bromo-4-
Iodoperfluorobutene-1, 2-bromo-4-iodoperfluorobutene-1 and the like are used. Examples of the aromatic iodine-containing bromine compound include monoiodomonobromo-substituted products at various substitution positions of benzene, Substituted iodomonobromo, monoiododibromo, (2-iodoethyl) and (2-bromoethyl) are used. These iodine-containing bromine compounds generally provide a fluorine-containing elastomer which is bonded to a molecular terminal to achieve crosslinking at a high rate. Therefore, iodine and bromine are used in an amount of about 0.001 to 5% by weight, preferably about 0.01 to 3% by weight, respectively.
It is combined to give a weight%.

As the iodine-containing compound, an aromatic compound or a perfluoroaromatic compound poly-substituted by an iodine atom or an alkyl iodide group represented by an ethyl iodide group is about 0.001 as iodine in a fluorine-containing elastomer.
Iodine-substituted saturated or unsaturated aliphatic hydrocarbon, fluoroaliphatic hydrocarbon or chlorofluoroaliphatic hydrocarbon in a proportion such that the amount of binding is about 5 to 5% by weight, preferably about 0.01 to 3% by weight. Is used in such a ratio as to give a binding amount of about 0.001 to 10% by weight as iodine in the fluorine-containing elastomer.

As the bromine-containing compound, an aromatic compound or perfluoroaromatic compound poly-substituted by an alkyl bromide group represented by a bromine atom or an ethyl bromide group,
A bromine-substituted product of a saturated aliphatic hydrocarbon is contained in an amount such that the amount of bromine in the fluorine-containing elastomer is about 0.001 to 5% by weight, preferably about 0.01 to 3% by weight, or
About 0.001 to 10% by weight as bromine in fluorine-containing elastomer
And the bromine-containing olefin is used in a proportion such that the bromine-containing olefin has a bond amount of about 0.05% by weight or more, generally about 0.3 to 1.5% by weight, as bromine in the fluorine-containing elastomer. Others such as 3- or 2-bromoperfluoropropyl perfluorovinyl ether can also be used.

Examples of the organic peroxide include n-butyl-4,4-bis (tert-butylperoxy) valerate, 1,1-bis (tert-butylperoxy) -3,3,5-trimethylcyclohexane, 1-bis (α, α-dimethylbutylperoxy) cyclohexane, 1,1-bis (α, α-dimethylbutylperoxy) -3,3,5-trimethylcyclohexane, tertiary butylperoxy-3,3,3 5-trimethylhexanoate, dicumyl peroxide, α, α-bis (tert-butylperoxy-m-isopropyl) benzene, 2,
5-dimethyl-2,5-di (tert-butylperoxy) hexyne-3, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane, 2,5-dimethyl-2,5- Di (tertiary amyl peroxy) hexane, benzoyl peroxide, lauroyl peroxide, tertiary butyl peroxyisopropyl carbonate, tertiary butyl peroxy laurate,
Tertiary butyl peroxyisobutyrate, tertiary butyl peroxy (2-ethylhexanoate), tertiary hexyl peroxy neohexanoate, tertiary butyl peroxypivalate, tertiary butyl peroxymaleic acid, 1 1,1-bis (tert-butylperoxy) cyclohexane or the like is used in an amount 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.

In the composition, tri (meth) allyl isocyanurate, tri (meth) allyl cyanurate, triallyl trimellitate, N, N'-m-phenylenebismaleimide,
Diallyl phthalate, tris (diallylamine) -s-
A polyfunctional compound such as triazine, triallyl phosphite, (di) ethylene glycol diacrylate, neopentyl glycol acrylate, etc., which improves mechanical strength and compression set, is added in an amount of about 0.1 to 15 parts by weight per 100 parts by weight of the fluorine-containing elastomer. Parts, preferably about 2 to 10 parts by weight. Further, if necessary, other additives such as a filler, a reinforcing agent, a plasticizer, a lubricant, a processing aid, and a pigment can be appropriately compounded.

The composition is prepared by a commonly used mixing method such as roll mixing, kneader mixing, Banbury mixing, solution mixing, etc., and the crosslinking thereof is generally performed at about 100 to 250 ° C. for about 1 to 120 minutes. Primary crosslinking and about 150-300 ° C
By secondary crosslinking performed for about 0 to 30 hours.

〔The invention's effect〕

It is unavoidable to generate toxic gas such as methyl iodide and methyl bromide during the thermal crosslinking of fluorine-containing elastomer containing iodine and / or bromine in the molecule with organic peroxide. 1-aralkyl or 1-alkyl-4-piperidinopyridinium
Benzimidazole-2-thioate or 5-aralkyl or 5-alkyl-1,5-diazabicyclo [4,3,
[0] By blending nonanium benzimidazole-2-thioate as an additive, the amount of the toxic gas generated can be effectively reduced.

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

Example 1 500 m capacity equipped with a bellows trap, thermometer and stirrer
Into a l separable flask, 15 g of 2-mercaptobenzimidazole, 14 g of sodium hydroxide and 200 ml of n-butanol were charged, and the mixture was heated and stirred at a liquid temperature of 40 to 45 ° C. When the mercaptobenzimidazole was completely dissolved, stirring was stopped. To form the sodium salt.

Separately, in a 500-ml separable flask equipped with a stirrer, 29 g of 1-benzyl-4-piperidinopyridinium chloride and 150 ml of n-butanol were charged and dissolved by stirring. When dissolved, the stirring was interrupted, and the sodium salt of mercaptobenzimidazole was n-
The mixture was stirred with heating at a liquid temperature of 40 to 45 ° C., the stirring was stopped after 30 minutes, and the mixture was allowed to stand at this temperature for 2 hours.

After that, the mixture was filtered under reduced pressure.At that time, a small amount of water was sprinkled on the orange-colored filter to remove sodium salt, and then a very small amount of acetone was sprinkled on top of it to promote dehydration. Continued to pass. The filtrate was transferred into a vacuum drier and dried under vacuum for 24 hours.
-Piperidinopyridinium benzimidazole-2-
Thioate was obtained in 31.9 g (67.4% yield).

Elemental analysis: Actual values: C 71.6%, H 5.9%, N 14.3%, S 8.1% Calculated values: C 71.8%, H 6.2%, N 14.0%, S 8.0% Infrared absorption spectrum: FIG. 1 FT-NMR analysis Frequency of iodine and bromine-containing fluorine elastomer (vinylidene fluoride-hexafluoropropene-tetrafluoroethylene terpolymer copolymerized in the presence of 1-bromo-2-iodoperfluoroethane) 100 parts (weight, same hereafter), MT carbon black 20 parts, triallyl isocyanurate (concentration 60%) 10 parts, 2,5-dimethyl-2,5-ditert-butylhexane (concentration 40%) 3.75 parts, 3 parts of lead oxide and 0.5 part or 1 part of 1-benzyl-4-piperidinopyridinium benzimidazole-2-thioate were kneaded with a roll to prepare a crosslinkable fluoroelastomer composition.

50 mg of each prepared composition was weighed and placed in a pyrolysis furnace, and the gas generated by pyrolysis at 180 ° C. for 15 minutes was subjected to gas chromatography / mass spectrum measurement apparatus (CG-MS manufactured by Shimadzu Corporation). -QP1000A) and detected CH ₃ Br (M / Z = 94) and CH ₃ I (M / Z = 142) in the MF mode. The detected generation amounts are shown in Table 1 below.

Example 2 Capacity 1 equipped with a bellows trap, thermometer and stirrer
30 g of 2-mercaptobenzimidazole, 28 g of sodium hydroxide and n-butanol
300 ml was charged, and the mixture was heated and stirred at a liquid temperature of 40 to 45 ° C. When the mercaptobenzimidazole was completely dissolved, the stirring was stopped to form a sodium salt.

Separately, 5-benzyl-1,5-diazabicyclo [4,
3,0] nonanium chloride 50g and n-butanol
100 ml was charged and dissolved by stirring. After dissolution, stirring was interrupted, and the above-mentioned sodium salt of mercaptobenzimidazole was mixed with n-butanol solution, and heating and stirring were continued at a liquid temperature of 40 to 45 ° C. After 30 minutes, stirring was stopped and the mixture was left at this temperature for 2 hours. Was placed.

Then, vacuum filtration is performed to obtain a white lump (mainly NaCl)
When the filtrate was allowed to stand for 24 hours, a large amount of white precipitated crystals were obtained there. This was subjected to a pressure measurement, and at that time, water was sprinkled with 5 times the amount of sodium salt obtained from the ash (residue remaining after ashing of the crude crystal) to remove sodium salt. Vacuum filtration was continued for 10 minutes while sprinkling a very small amount of acetone to promote dehydration. The filtered material was transferred to a vacuum drying garment, vacuum dried for 24 hours, and
57.0 g of benzyl-1,5-diazabicyclo [4,3,0] nonanium benzimidazole-2-thioate (yield 78.0 g)
%).

Elemental analysis: Actual values: C 69.2%, H 6.1%, N 15.8%, S 9.0% Calculated values: C 69.2%, H 6.6%, N 15.4%, S 8.8% Infrared absorption spectrum: FIG. 3 FT-NMR analysis Frequency: 100 parts of iodine and bromine-containing fluorine-containing elastomer used in Example 1, 20 parts of MT carbon black, 10 parts of triallyl isocyanurate (concentration: 60%), 2,5-dimethyl-2 3.75 parts of 5,5-di-tert-butylhexane (concentration: 40%),
3 parts of lead oxide and 0.5 part, 1 part or 1.5 parts of 5-benzyl-1,5-diazabicyclo [4,3,0] nonanium benzimidazole-2-thioate are kneaded with a roll,
A crosslinkable fluorine-containing elastomer composition was prepared.

50 mg of each prepared composition was weighed and placed in a pyrolysis furnace, and the gas generated by pyrolysis at 180 ° C. for 15 minutes was subjected to gas chromatography / mass spectrometry (GC-MS- manufactured by Shimadzu Corporation). QP1000A) and detected CH ₃ Br (M / Z = 94) and CH ₃ I (M / Z = 142) in the MF mode. The detected generation amounts are shown in Table 2 below.

[Brief description of the drawings]

FIGS. 1 and 3 are infrared absorption spectra of the 2-mercaptobenzimidazole salts obtained in Examples 1 and 2, respectively. FIGS. 2 and 4 are spectra showing the resonance frequency of the 2-mercaptobenzimidazole salt obtained in Examples 1 and 2 by FT-NMR analysis.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08L 27/12 C08L 27/12

Claims (4)

(57) [Claims] (1) 1-aralkyl or 1-alkyl-4-
Piperidinopyridinium benzimidazole-2-thioate. (2) 5-aralkyl or 5-alkyl-1,5
-Diazabicyclo [4,3,0] nonanium benzimidazole-2-thioate. 3. A composition comprising a fluorine-containing elastomer containing iodine and / or bromine in the molecule, an organic peroxide and 1-aralkyl or 1-alkyl-4-piperidinopyridinium benzimidazole-2-thioate. Crosslinkable fluorine-containing elastomer composition. 4. A fluorine-containing elastomer containing iodine and / or bromine in the molecule, an organic peroxide and 5-aralkyl or 5-alkyl-1,5-diazabicyclo [4,3,0] nonanium benzimidazole-2. -A crosslinkable fluorine-containing elastomer composition containing thioate.