JPH03197545A - New quaternary benzimidazole salt, and crosslinkable fluoroelastomer composition containing the same - Google Patents

Abstract

PURPOSE:To reduce the amt. of CH3I and/or CH3Br generated during the decomposition of an org. peroxide by compounding a fluoroelastomer contg. I and/or Br in the molecule with an org. peroxide and a specific quaternary benzimidazole salt. CONSTITUTION:The title compsn. comprises 100 pts.wt. fluoroelastomer contg. 0.001-10wt.% I and/or Br in the molecule; 0.1-5 pts.wt. quaternary benzimidazole salt selected from the group consisting of a 1-aralkyl- or 1-alkyl-4- piperidinopyridinium benzimidazole and 5-aralkyl- or 5-alkyl-1,5- diazabicyclo[4,3,0]nonanium benzimidazole-2-thioate; and 0.1-10 pts.wt. org. peroxide [e.g. n-butyl 4,4-bis(t-butylperoxy)valerate].

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] 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 disstomer containing iodine and/or bromine in the molecule, and a crosslinkable fluorine-containing elastomer composition containing the same.

[Conventional technology]

Organic peroxide crosslinking of fluorine-containing elastomers provides crosslinked products with excellent engine oil resistance and solvent resistance.
It is considered to be superior to conventional crosslinking methods such as polyol crosslinking and polyamine crosslinking.

The present applicant and others have proposed fluorine-containing elastomers crosslinked with organic peroxides containing iodine and bromine in the molecule (Japanese Patent Application No. 62-58145, 62-232
, No. 407, No. 53-125, 491, No. 6
Publication No. 0-221,409, Publication No. 59-20,310, Publication No. 62-260.807, Japanese Patent Publication No. 54-15
Publication No. 85, etc.).

However, when the organic peroxide used for this crosslinking is decomposed, methyl iodide (C
It generates toxic substances such as H,I) or methyl bromide (CH3Br), which is a problem that cannot be ignored from the viewpoint of maintaining the workplace and surrounding environment.

[Problem to be solved by the invention]

One object of the present invention is to provide CH,
The object of the present invention is to provide a new additive that can significantly reduce the amount of CH3Br and CH3Br generated.

Another object of the present invention is to provide a crosslinkable composition of a fluorine-containing elastomer containing iodine and/or bromine, which contains such a novel additive.

[Means to solve the problem]

The novel additives that achieve the object of the present invention are 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,O]nonanium benzimidazole-2 With these formulas , R: alkyl group having 1 to 24 carbon atoms, 7 to 24 carbon atoms
20 Aralkyl Groups The compound of the above formula [I] is prepared by separately treating 4-piperidinopyridinium halide, which preferably has a benzyl group at the l-position, and an alkali metal salt of 2-mercaptobenzimidazole in a polar solvent (water). , alcohols, ketones, esters, amides, ethers, etc.) and stirring and mixing these solutions at approximately -20 to +40°C, generally at room temperature. can be done.

In addition, the compound of the above formula [■] is composed of a known 5-aralkyl or 5-alkyl substituted, preferably 5-benzyl substituted 1,5-diazabicyclo[4,3,0]nonanium halide and a 2-mercaptobenzate. It can be easily produced by the same reaction method as above using an alkali metal salt of imidazole.

Quaternary benzimidazole-2 thus obtained
-Thioate compound [I] or [II] is an iodine- and/or bromine-containing fluorine-containing elastomer 1, respectively.
0.00 parts by weight, preferably about 0.1 to 5 parts by weight, preferably about 0.00 parts by weight.
It is used in an amount of 5 to 3 parts by weight to form a crosslinkable fluorine-containing elastomer composition together with the 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, such as vinylidene fluoride, Tetrafluoroethylene, hexafluoropropene, pentafluoropropene, 4-lortrifluoroethylene, methyl perfluorovinyl ether, ethyl perfluorovinyl ether, n- or iso-propyl 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 tert-butyl vinyl ether), perfluoro(n- or iso-amyl vinyl ether),
At least one type of perfluoro(propoxypropyl vinyl ether) is mainly used, and in addition to this, vinyl fluoride, trifluoroethylene, perfluorocyclobutene, perfluoro(methylcyclopropene), hexafluoroisobutyne, 1,2 .2-Trifluorostyrene, perfluorostyrene, etc. are also used.

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

Examples of olefinic compounds include those having 2 to 6 carbon atoms, such as unsaturated vinyl esters such as ethylene, propylene, butene, and vinyl acetate, and alkyl vinyl ethers such as methyl vinyl ether and ethyl vinyl ether. Copolymerization is carried out in a proportion of 1 to 50 mol%.

Further, as the fluorine-containing diene, for example, perfluoro-
1,3-butadiene, perfluoro-1,4-pentadiene, 1. ．． 1.2-)-Lifluoro-1,3-butadiene, 1.1.2-trifluoro-1,4-pentadiene, 1,1,2,3゜3-pentafluoro-1,4-pentadiene, perfluoro Examples include those having 4 to 8 carbon atoms, such as -1,7-octadiene, perfluorodivinyl ether, perfluorovinyl perfluoroallyl ether, vinyl perfluoroallyl ether, and perfluorovinyl vinyl ether. These fluorine-containing dienes are preferably copolymerized so that they are present in the fluorine-containing elastomer in a proportion of about 1 mol % or less. If the copolymer is copolymerized in a proportion larger than this, gelation of the copolymer elastomer will become significant, and processability (flow characteristics) and elongation of the vulcanizate will deteriorate.

Specific fluorine-containing olefin copolymers include hexafluoropropene-vinylidene fluoride copolymer, hexafluoropropene-vinylidene fluoride-tetrafluoroethylene ternary copolymer, and tetrafluoroethylene-vinylidene fluoride-perfluoroethylene copolymer. (methyl vinyl ether)
Ternary copolymer, tetrafluoroethylene-vinylidene fluoride-perfluoro(propyl vinyl ether) ternary copolymer, tetrafluoroethylene-perfluoro(propoxypropyl vinyl ether) copolymer, tetrafluoroethylene-perfluoro(methyl) vinyl ether)
copolymer, tetrafluoroethylene-propylene copolymer, tetrafluoroethylene-vinylidene fluoride-hexafluoropropene-pentafluoropropene quaternary copolymer, tetrafluoroethylene-hexafluoropropene-vinylidene fluoride 7 = 8- Fluoro(methyl vinyl ether) quaternary copolymer, tetrafluoroethylene-hexafluoropropene-hexafluoroisobutyne ternary copolymer, tetrafluoroethylene-cyclohexyl vinyl ether copolymer, hexafluoropropene-vinylidene fluoride-chlorotripolymer Fluoroethylene ternary copolymer, vinylidene fluoride-tetrafluoroethylene-methyl perfluorovinyl ether ternary copolymer, vinylidene fluoride-tetrafluoroethyl-n-butyl perfluorovinyl ether ternary copolymer, vinylidene fluoride-methyl Perfluorovinyl ether-perfluoro(methyl vinyl ether) terpolymer, tetrafluoroethylene-methyl perfluorovinyl ether-perfluoro(methyl vinyl ether) 3
Original copolymer, vinylidene fluoride hexafluoropropene-tetrafluoroethylene-methyl perfluorovinyl ether quaternary copolymer, tetrafluoroethylene-rope chil perfluorovinyl ether-perfluoro(methyl vinyl ether) ternary copolymer , vinylidene fluoride-n-butyl perfluorovinyl ether copolymer, tetrafluoroethylene-propylene-n-butyl perfluorovinyl ether ternary copolymer, tetrafluoroethylene-vinylidene fluoride-propylene-〇-butyl perfluorovinyl ether quaternary copolymer Examples include copolymers.

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

During this polymerization reaction, if an iodine-containing bromine compound, an iodine-containing compound, or a bromine-containing compound is co-present, iodine and/or bromine will be introduced into the fluorine-containing olefin copolymer, and the crosslinking point during organic peroxide crosslinking will occur. form.

As the iodine-containing bromine compound, the general formula RBrnI (R
: fluorohydrocarbon group, chlorofluorohydrocarbon group, chlorohydrocarbon group or hydrocarbon group, n, m: 1 or 2
), preferably in which n and m are each 1
are used. Examples of chain iodine-containing bromine compounds include 1-bromo-2-iodoperfluoroethane, 1-bromo-3-iodoperfluoropropane, and 1-bromo-2-iodoperfluoropropane.
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, etc. are used, and aromatic iodine-containing bromine compounds include, for example, monoiodo monobromo substituted products, short monobromo substituted products, monobromo substituted products at various substitution positions of benzene. Iododibromo substituted products, (2-iodoethyl) and (2-bromoethyl) substituted products, etc. are used. These iodine-containing bromine compounds are generally bonded to the molecular ends to provide a fluorine-containing elastomer that can efficiently achieve crosslinking, and for this purpose, the amount of iodine and bromine, respectively, is about 0.001 to 5% by weight, preferably about 0.00% by weight. 01 to 3% by weight.

As the iodine-containing compound, an aromatic compound polysubstituted with an iodine atom or an iodized alkyl group represented by an ethyl iodide group or a perfluoroaromatic compound is used, which contains about 0.00% of the iodine in the fluorine-containing elastomer.
or of saturated or unsaturated aliphatic hydrocarbons, fluoroaliphatic hydrocarbons or chlorofluoroaliphatic hydrocarbons, in proportions such that the bond amount is from 1 to 5 by weight 2, preferably from about 0.01 to 3 by weight 2. The iodine-substituted products are used in such a proportion that the amount of iodine bound in the fluorine-containing elastomer is approximately 0.001 to 10% by weight.

As the bromine-containing compound, an aromatic compound polysubstituted with a bromine atom or an alkyl bromide group represented by an ethyl bromide group or a perfluoro aromatic compound is used, and the bromine content in the fluorine-containing elastomer is about o, ooi to 5 The bromine substituted product of the saturated aliphatic hydrocarbon is bonded in a proportion such that the amount of bromine in the fluorine-containing elastomer is from about 0.001 to 3% by weight, preferably about 0.01 to 3% by weight.
The amount of bromine-containing olefin in the fluorine-containing elastomer is approximately 0 as bromine in the fluorinated elastomer.
．． 05% by weight 1- or more, generally used in proportions such that the binding amount is about 0.3 to 1.5% by weight, and in addition 3- or 2-
Bromoperfluoropropyl perfluorovinyl ether and the like can also be used.

Examples of organic peroxides include n-butyl-4,4-bis(tert-butylperoxy)valerate, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, 1, 1-bis(α,α-dimethylbutylperoxy)cyclohexane, ■,1-bis(α,α-
dimethylbutylperoxy)-3,3,5-trimethylcyclohexane, tert-butylperoxy-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(tert-amylperoxy)hexane,
Benzoyl peroxide, lauroyl peroxide, tert-butyl peroxyisopropyl carbonate, tert-butyl peroxylaurate, tert-butyl peroxy 12
- tertiary butyl peroxy (2-ethylhexanoate), tertiary hexyl peroxyneohexanoate, tertiary butyl peroxypiparate, tertiary butyl peroxymaleic acid, 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'-+n-phenylene bismaleimide,
Diallyl phthalate, tris(diallylamine)-8-
A polyfunctional compound such as triazine, triallyl phosphite, (di)ethylene glycol diacrylate, neopentyl glycol diacrylate, etc. that improves mechanical strength, compression set, etc. is added at about 0.1% per 100 parts by weight of the fluorine-containing elastomer. It is desirable to add it in a proportion of ~15 parts by weight, preferably about 2 to 10 parts by weight. In addition, other additives such as fillers, reinforcing agents, plasticizers, lubricants, processing aids, pigments, etc. can also be blended as appropriate.

The composition is prepared by commonly used mixing methods such as roll mixing, kneader mixing, Banbury mixing, and solution mixing. cross-linked and about 150
Secondary crosslinking is carried out at ~300°C for about 0 to 30 hours.

〔Effect of the invention〕

It is unavoidable that toxic gases such as methyl iodide and methyl bromide are generated during thermal crosslinking of fluorine-containing distomers containing iodine and/or bromine in their molecules with organic peroxides; 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.

〔Example〕

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

Example 1 Capacity 500 with corrugated tube trap, thermometer and stirrer
m In a Q separable flask, 15 g of 2-mercaptobenzimidazole, 14 g of sodium hydroxide, and n
- Pour 200m of butanol Q, liquid temperature 40-45℃
When the mercaptobenzimidazole was completely dissolved, the stirring was stopped to form a sodium salt.

Separately, in a 500 m Q separable flask equipped with a stirrer, 29 g of 1-benzyl-4-piperidinopyridinium chloride and 15 g of n-butanol were added.
0 mΩ was charged and stirred to dissolve. Once dissolved, the stirring is stopped, and the n-butanol solution of the sodium salt of mercaptobenzimidazole is mixed in, and the liquid temperature is 40-40%.
Heating and stirring was continued at 5°C, stirring was stopped after 30 minutes, and the mixture was left at this temperature for 2 hours.

After that, pass through a vacuum port, and at that time, sprinkle a small amount of water on the orange-colored filtrate to remove sodium salt, and then sprinkle a very small amount of acetone on top of it to promote dehydration. The vacuum passage was continued for a minute.

This sip was transferred to a vacuum dryer and vacuum dried for 24 hours to obtain 31.9 g of 1-benzyl-4-piperidinopyridinium benzimidazole-2-thioate (yield 67
．． 4%).

Elemental analysis: Actual values: C71, parts, H5,9%, N 14.3%,
, 58.1% Calculated value: C71.8%, ■6.2%, N
14.0%, 88.0% Infrared absorption spectrum: Fig. 1 Resonance frequency in FT-NMR analysis: Fig. 2 Iodine- and bromine-containing fluorine-containing elastomer (compounded in the coexistence of 1-bromo-2-iodoperfluoroethane) Polymerized vinylidene fluoride-hexafluoropropene-tetrafluoroethylene terpolymer) 100 parts (weight, same hereinafter), M
20 parts of T carbon black, 10 parts of triallylisocyanurate (concentration 60%), 2,5-dimethyl-2,5-
Cross-linkable A fluorine-containing elastomer composition was prepared.

Weigh out 50 mg of each of the prepared compositions, put them into a pyrolysis furnace, and pyrolyze them at 180°C for 15 minutes. MS-QP1000A)
CH3Br (M/Z=94) and CHlI (A/Z=142) were detected in MF mode. The detected amounts are shown in Table 1 below.

Table 1 0 0.1221 3.127
0.5 0.0589 0.78
851 0.0179 0.3
562 Example 2 30 g of 2-mercaptobenzimidazole, 28 g of sodium hydroxide, and 300 m of n-butanol were charged into a separable flask with a capacity of IQ equipped with a corrugated pipe trap, a thermometer, and a stirrer, and the mixture was heated at a liquid temperature of 40 to 45°C. The mixture was heated and stirred, and when the mercaptobenzimidazole was completely dissolved, the stirring was stopped to form a salt of 1-3.

Separately, 5-benzyl-1,5-diazabicyclo[4
, 3. 50 g of OF nonanium chloride and 100 mρ of n-butanol were charged and dissolved by stirring.

Once dissolved, the stirring was stopped, and the n-butanol solution of the sodium salt of mercaptobenzimidazole was mixed in, and the mixture was heated and stirred at a temperature of 40 to 45°C. After 30 minutes, the stirring was stopped, and the mixture was kept at this temperature for 2 hours. I placed it.

After that, vacuum filtration was performed, and white 0 mass (mainly NaCQ)
) and 0 liquid, and when the 0 liquid was allowed to stand for 24 hours, a large amount of white precipitated crystals were obtained. This is passed through a vacuum port, at which time water in an amount 5 times the amount of sodium salt obtained from the ash (residue left after ashing the crude crystals) is sprinkled over the whole to remove sodium salt, and then While sprinkling a small amount of acetone to promote dehydration, vacuum filtration was continued for 10 minutes.

The filtrate was transferred to a vacuum dryer and vacuum-dried for 24 hours.
0] Nonanium benzimidazole-2-thioate was obtained in an amount of 57.0 g (yield 78.0%).

Elemental analysis: Actual values: C69.2%, H6.1%, N 15.8%
, 39.0% Calculated value: C69.2%, ) 16.6%,
N 15.4%, 58.8% infrared absorption spectrum:
Figure 3: FT=resonance frequency in NMR analysis: Figure 4: Fluorine-containing elastomer 1 containing iodine and bromine used in Example 1
00 parts, 20 parts of revised carbon black, 10 parts of triallylisocyanurate (concentration 60%), 2,5-dimethyl-
2,5-di-tert-butylhexane (concentration 40%) 3.75
part, 3 parts of lead oxide and 5-benzyl-1,5-diazabicyclo[4,3,0]nonaniumbenzimidazole-
A crosslinkable fluorine-containing elastomer composition was prepared by kneading 0.5 part, 1 part, or 1.5 parts of 2-thioate using a roll.

Weighed out 501 g of each of the prepared compositions, placed them in a thermal decomposition furnace, and thermally decomposed them at 180°C for 15 minutes. -QP100OA) and detected CH3Br (M/Z==94) and CH3I19 20- (M/Z=142) in MF mode. The detected amount is
It is shown in Table 2 below.

Table 2 2-mercaptobenz CH, Br imidazole salt constant tlin 0 0.1221 0.5 0.05501
0.0192 1.5 0.0080

[Brief explanation of drawings]

FIG. 1 and FIG. 3 are infrared absorption spectra of the 2-mercaptobenzimidazole salts obtained in Examples 1 and 2, respectively. Moreover, FIG. 2 and FIG. 4 are spectra showing the resonance frequencies in FT-NMR analysis of the 2-mercaptobenzimidazole salts obtained in Examples 1 and 2, respectively. From CHl σ 3.127 1.0555 0.3826 0.1425

Claims (1)

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 fluorine-containing elastomer containing iodine and/or bromine in the molecule, a crosslinkable compound containing an organic peroxide and 1-aralkyl or 1-alkyl-4-piperidinopyridinium benzimidazole-2-thioate. Fluoroelastomer composition. 4. Fluorine-containing elastomer containing iodine and/or bromine in the molecule, organic peroxide and 5-aralkyl or 5-alkyl-1,5-diazabicyclo[4,3
, 0] A crosslinkable fluorine-containing elastomer composition containing nonanium benzimidazole-2-thioate.