JPWO2006090728A1 - Fluorine-containing elastomer and method for producing fluorine-containing elastomer - Google Patents

Abstract

The present invention provides a method for producing a fluorine-containing elastomer containing a group having an unsaturated bond at the main chain end and / or side chain end. Moreover, the curable composition containing this fluorine-containing elastomer and the molded article obtained by bridge | crosslinking this curable composition are provided. An alkali metal, an alkaline earth metal, and / or a transition metal is added to the fluorine-containing elastomer having a site represented by the general formula (1): or the general formula (2): at the main chain end and / or the side chain end. This is a method for producing a fluorinated elastomer, which comprises a step of converting a site represented by the general formula (1) or (2) into a site represented by the general formula (3):

Description

  The present invention relates to a method for producing a fluorine-containing elastomer containing a group having an unsaturated bond at the main chain end and / or side chain end. The present invention also relates to a curable composition containing the fluorine-containing elastomer and a molded product obtained by crosslinking the curable composition.

  Fluorine-containing elastomers are widely used in fields such as the automobile industry, semiconductor industry, and chemical industry as sealing materials in harsh environments because they exhibit excellent chemical resistance, solvent resistance, and heat resistance. .

  However, with the advancement of technology, the required characteristics become more severe, and in various fields such as aerospace field, semiconductor manufacturing equipment field, chemical plant field, automobile industry, etc., superior heat resistance, chemical resistance, solvent resistance And processability are required.

  In order to reinforce these various properties, a composition comprising a fluorine-containing elastomer having a vinyl group or an allyl group introduced at the terminal and a composition comprising a crosslinking agent have been developed.

For example, a composition comprising a fluorine-containing elastomer having a structure of —Si (R ^′ ) (CH ₃ ) CH═CH ₂ at both ends and a curing agent having a specific structure is disclosed (for example, JP-A-56-56). -829). However, since this fluorine-containing elastomer has a silicone structure, it has a problem of being vulnerable to acid.

In addition, a curable composition containing a main chain terminal ester group-containing fluorine oligomer and an unsaturated group-containing amine and a main chain both terminal unsaturated group-containing fluorine oligomer (see, for example, JP-A-2001-81131). And a composition comprising a fluorine-containing amide compound in which —Si (R ¹ ) (R ² ) CH═CH ₂ is bonded to both ends of the fluorine-containing elastomer via an amide bond and a fluorine-containing organosiloxane. (See, for example, JP-A-9-95615). However, since the unsaturated group of the fluorine-containing oligomer or elastomer is introduced into the main chain via an amide bond, it has a problem of being weak against alkali.

  Furthermore, a curable composition comprising a fluorine-containing elastomer having hydroxyl groups at both ends and a fluorine-containing elastomer having allyl groups at both ends obtained by reacting a compound having an isocyanate group and a vinyl group is disclosed (for example, , See International Publication No. 2004/050758 pamphlet). However, the fluorine-containing elastomer has a problem that heat resistance is inferior because an unsaturated group is introduced into the main chain via a urethane bond.

  As described above, as a method for introducing a vinyl group into a terminal, many methods are generally known which are introduced via a bond such as an amide bond. However, these bonded parts have problems such as low heat resistance and weakness against acids and alkalis. Therefore, these bonding parts are resistant to heat and acids and alkalis, and contain a vinyl or allyl group introduced by a carbon-carbon bond. The development of fluoroelastomers was anxious.

  The present invention provides a method for producing a fluorine-containing elastomer containing a group having an unsaturated bond at the main chain end and / or side chain end. Moreover, the curable composition containing this fluorine-containing elastomer and the molded article obtained by bridge | crosslinking this curable composition are provided.

  That is, the present invention provides the general formula (1) at the end of the main chain and / or the side chain end:

Or general formula (2):

Wherein X ¹ , X ² and X ³ are the same or different and are a hydrogen atom, a fluorine atom, —CH ₃ or —CF ₃ , Y ¹ is an iodine atom, a bromine atom or a chlorine atom, and Z is fluorine An atom, an iodine atom, a bromine atom, a chlorine atom, —OR ¹ , or —SR ¹ (R ¹ is an alkyl group having 1 to 5 carbon atoms, an acyl group having 1 to 5 carbon atoms, a benzoyl group, an aryl group, a tosyl group, A trifluoromethanesulfonyl group, and part or all of the hydrogen atoms of these groups may be substituted with fluorine atoms))
In the fluorine-containing elastomer having a site represented by
An alkali metal, an alkaline earth metal, and / or a transition metal,
The site represented by the general formula (1) or (2) is represented by the general formula (3):

(Wherein X ¹ , X ² and X ³ are the same as above)
The manufacturing method of a fluorine-containing elastomer including the process converted into the site | part shown by these.

  Furthermore, an oxidant is allowed to act so that the general formula (3):

(Wherein X ¹ , X ² and X ³ are the same as above)
It is preferable to include the process of converting the site | part shown by -COOH.

The present invention also provides a compound represented by the general formula (4):
B _a- (M)-(A) -C _b (4)
(In the formula, M is a structural unit derived from vinylidene fluoride and / or tetrafluoroethylene, A is a structural unit derived from an ethylenic monomer copolymerizable with M, and B and C are the same or different. General formula (5):

Wherein X ¹ , X ² and X ³ are the same or different and are a hydrogen atom, a fluorine atom, —CH ₃ or —CF ₃ , and R ² is an alkylene which may contain an ether bond having 1 to 5 carbon atoms. A part of or all of the hydrogen atoms may be substituted with fluorine atoms, and n is an integer of 0 or more)
Wherein a and b are each 0 or 1, and a + b ≠ 0. )
It is related with the fluorine-containing elastomer shown by these.

  The fluorine-containing elastomer is preferably a vinylidene fluoride-based fluororubber.

  The number average molecular weight is preferably 500 to 500,000.

  The present invention also relates to a curable composition containing the fluorine-containing elastomer and a molded product obtained by crosslinking the curable composition.

  The present invention provides the general formula (1) at the main chain end and / or the side chain end:

Or general formula (2):

Wherein X ¹ , X ² and X ³ are the same or different and are a hydrogen atom, a fluorine atom, —CH ₃ or —CF ₃ , Y ¹ is an iodine atom, a bromine atom or a chlorine atom, and Z is fluorine An atom, an iodine atom, a bromine atom, a chlorine atom, —OR ¹ , or —SR ¹ (R ¹ is an alkyl group having 1 to 5 carbon atoms, an acyl group having 1 to 5 carbon atoms, a benzoyl group, an aryl group, a tosyl group, A trifluoromethanesulfonyl group, and part or all of the hydrogen atoms of these groups may be substituted with fluorine atoms))
In the fluorine-containing elastomer having a site represented by
By reacting an alkali metal, an alkaline earth metal, and / or a transition metal, a site represented by the general formula (1) or (2) is represented by the general formula (3):

(Wherein X ¹ , X ² and X ³ are the same as above)
The manufacturing method of a fluorine-containing elastomer including the process converted into the site | part shown by these.

  According to the production method of the present invention, at the end of the main chain and / or the end of the side chain, the general formula (1):

Or general formula (2):

(Wherein, X ¹ , X ² , X ³ , Y ¹ , Z are the same as above)
When an alkali metal, an alkaline earth metal, and / or a transition metal is allowed to act on various fluorine-containing elastomers having the moiety represented by the following formula, dehalogenation reaction occurs, and Y ¹ Z is eliminated, and the general formula (3 ):

(Wherein X ¹ , X ² and X ³ are the same as above)
It is possible to economically and easily convert to the site having an unsaturated bond represented by

  Moreover, in the method of the present invention, a group having an unsaturated bond can be introduced via a carbon-carbon bond at the main chain end and / or side chain end of the fluorine-containing elastomer. The skeleton of the main chain of the fluorine-containing elastomer is composed only of carbon-carbon bonds. By crosslinking such a curable composition containing a fluorine-containing elastomer, a molded product having excellent heat resistance and a small compression set (CS) can be obtained.

  The fluorine-containing elastomer used in the present invention is not particularly limited as long as it is a fluorine-containing elastomer having a moiety represented by the general formula (1) or (2) at the main chain terminal and / or the side chain terminal.

X ¹ , X ² and X ³ in the general formula (1) and the general formula (2) are the same or different and are a hydrogen atom, a fluorine atom, —CH ₃ or —CF ₃ . Among these, a hydrogen atom and a fluorine atom are preferable from the viewpoint of not sterically hindering the reactivity of the unsaturated bond, and a fluorine atom and —CF ₃ are preferable from the viewpoint of heat resistance at the crosslinking point after curing, From the viewpoint of the reactivity of the curing reaction by hydrosilylation reaction, a hydrogen atom is preferred.

Y ¹ is an iodine atom, a bromine atom or a chlorine atom. Among these, iodine is easy because it can be easily introduced into the polymer end, and has high reactivity with alkali metals, alkaline earth metals, or transition metals. An atom and a bromine atom are preferable, and an iodine atom is more preferable.

Z acts as a leaving group and is a fluorine atom, an iodine atom, a bromine atom, a chlorine atom, —OR ¹ , or —SR ¹ (R ¹ is an alkyl group having 1 to 5 carbon atoms, 1 to 1 carbon atoms, 5 is an acyl group, a benzoyl group, an aryl group, a tosyl group, a trifluoromethanesulfonyl group, or a part or all of the hydrogen atoms of these groups are substituted with fluorine atoms). From the viewpoint of efficiently occurring, a fluorine atom, an iodine atom, a bromine atom, and -OR ¹ are preferable. Further, among the —OR ^1, the more stable the —OR ¹ anion generated by elimination, the easier it is to eliminate, so R ¹ is preferably an alkyl group, acyl group, fluorine-containing alkyl group, tosyl group, or trifluoromethanesulfonyl group. In view of availability, R ¹ is preferably an alkyl group or an acyl group.

Among these, since the elimination reaction occurs efficiently and the introduction is easy, the sites represented by the general formulas (1) and (2) include —CF ₂ CH ₂ I, —CF ₂ CFICF _3. ,

What has a site | part shown by is more preferable.

  As a method for introducing the site represented by the general formula (1) or (2) at the terminal, a method of copolymerizing a monomer having a crosslinking site at the time of polymerization of the fluorine-containing elastomer, or iodine transfer polymerization as described later. Examples thereof include a polymerization method and a method of adding a monomer to the iodine terminal of a fluorine-containing elastomer obtained by an iodine transfer polymerization method.

  Examples of the fluorine-containing elastomer include fluororubber (a), thermoplastic fluororubber (b), and rubber compositions containing these fluororubbers. Among these, fluororubber (a) is preferable.

  Examples of the fluororubber (a) include non-perfluorofluororubber (a-1) and perfluorofluororubber (a-2). In addition, perfluoro fluororubber means the thing which 90 mol% or more consists of a perfluoro monomer among the structural units.

  Non-perfluoro fluororubber (a-1) includes vinylidene fluoride (VdF) fluororubber, tetrafluoroethylene (TFE) / propylene fluororubber, tetrafluoroethylene (TFE) / propylene / vinylidene fluoride (VdF). Fluorine rubber, ethylene / hexafluoropropylene (HFP) fluorine rubber, ethylene / hexafluoropropylene (HFP) / vinylidene fluoride (VdF) fluorine rubber, ethylene / hexafluoropropylene (HFP) / tetrafluoroethylene (TFE) Fluororubbers, fluorosilicone fluororubbers, fluorophosphazene fluororubbers, etc., and these can be used alone or in any combination as long as the effects of the present invention are not impaired. Two isopropylidene fluoride (VdF) type fluorine-containing rubbers, it is preferable to use a tetrafluoroethylene (TFE) / propylene fluorine rubber.

  As the vinylidene fluoride (VdF) fluororubber, those represented by the following general formula (6) are preferable.

― (M ¹ ) ― (M ² ) ― (N ¹ ) ― (6)
(In the formula, the structural unit M ¹ is a structural unit derived from vinylidene fluoride (m ¹ ), the structural unit M ² is a structural unit derived from a fluorine-containing ethylenic monomer (m ² ), and the structural unit N ¹ Is a repeating unit derived from the monomer (m ¹ ) and the monomer (n ¹ ) copolymerizable with the monomer (m ² )

Formula (6) Among the vinylidene fluoride (VdF) fluorine rubber represented by the structural unit M ¹ 45 to 85 mol%, preferably not containing a structural unit M ² fifty-five to fifteen mole%, more preferably structure The unit M ¹ is 50 to 80 mol%, and the structural unit M ² is 50 to 20 mol%. The structural unit N ¹ is preferably 0 to 10 mol% with respect to the total amount of the structural unit M ¹ and the structural unit M ² .

As the fluorine-containing ethylenic monomer (m ² ), one or more monomers can be used. For example, tetrafluoroethylene (TFE), chlorotrifluoroethylene (CTFE), trifluoroethylene, hexafluoro Fluorine-containing monomers such as propylene (HFP), trifluoropropylene, tetrafluoropropylene, pentafluoropropylene, trifluorobutene, tetrafluoroisobutene, perfluoro (alkyl vinyl ether) (PAVE), and vinyl fluoride can be mentioned. Of these, tetrafluoroethylene, hexafluoropropylene, and perfluoro (alkyl vinyl ether) are preferable.

The monomer (n ¹ ) may be any monomer as long as it is copolymerizable with the monomer (m ¹ ) and the monomer (m ² ). For example, ethylene, propylene, alkyl vinyl ether, etc. can give.

The monomer (n ¹ ) is preferably a monomer that gives a cross-linked site.

As a monomer giving such a crosslinking site, the general formula (7):
CY ² ₂ = CY ² -R _f ¹ CHR ³ X ⁴ (7)
Wherein Y ² is a hydrogen atom, fluorine atom or —CH ₃ , R _f ¹ is a fluoroalkylene group, perfluoroalkylene group, fluoropolyoxyalkylene group or perfluoropolyoxyalkylene group, and R ³ is hydrogen. Atom or —CH ₃ , X ⁴ is an iodine atom or a bromine atom), or an iodine or bromine-containing monomer represented by the general formula (8):
_{CF 2 = CFO (CF 2 CF} (CF 3) O) m (CF 2) n -X 5 (8)
(Wherein m is an integer of 0 to 5, n is an integer of 1 to 3, and X ⁵ is a cyano group, a carboxyl group, an alkoxycarbonyl group, a bromine atom, an iodine atom), General formula (9):
CH ₂ = CH (CF ₂ ) _n I (9)
(Wherein n is an integer of 1 to 10) and the like, and examples thereof include perfluoro (described in JP-B-5-63482 and JP-A-7-316234). Iodine-containing monomers such as 6,6-dihydro-6-iodo-3-oxa-1-hexene) and perfluoro (5-iodo-3-oxa-1-pentene), JP-A-4-505341 Bromine-containing monomer described, cyano group-containing monomer, carboxyl group-containing monomer, alkoxycarbonyl group-containing as described in JP-A-4-505345, JP-A-5-500070 And monomers. These can be used alone or in any combination.

  This iodine atom and bromine atom can introduce a vinyl group at the terminal by a dehalogenation reaction. In addition, a vinyl group, an iodine atom, a bromine atom, a cyano group, a carboxyl group, and an alkoxycarbonyl group can function as a crosslinking point.

  Specific examples of such vinylidene fluoride (VdF) -based fluororubber include VdF-HFP rubber, VdF-HFP-TFE rubber, VdF-CTFE rubber, VdF-CTFE-TFE rubber, and the like. It is done.

  As the tetrafluoroethylene (TFE) / propylene-based fluororubber, those represented by the following general formula (10) are preferable.

― (M ³ ) ― (M ⁴ ) ― (N ² ) ― (10)
(In the formula, the structural unit M ³ is a structural unit derived from tetrafluoroethylene (m ³ ), the structural unit M ⁴ is a structural unit derived from propylene (m ⁴ ), and the structural unit N ² is a monomer (m ³ ) and repeating unit derived from monomer (n ² ) copolymerizable with monomer (m ⁴ ))

Formula (10) tetrafluoroethylene represented by (TFE) / Among the propylene fluorine rubber, a structural unit M ³ 40 to 70 mol%, preferably not containing a structural unit M ⁴ 60 to 30 mol%, more preferably it is a structural unit M ³ 50-60 mol%, in which the structural unit M ⁴ 50-40 mol%. The structural unit N ² is preferably 0 to 40 mol% with respect to the total amount of the structural unit M ³ and the structural unit M ⁴ .

The monomer (n ² ) may be any monomer that can be copolymerized with the monomer (m ³ ) and the monomer (m ⁴ ). Is preferred. Examples thereof include vinylidene fluoride and ethylene.

  As perfluoro fluororubber (a-2), what is represented by following General formula (11) is preferable.

― (M ⁵ ) ― (M ⁶ ) ― (N ³ ) ― (11)
(In the formula, structural unit M ⁵ is a structural unit derived from tetrafluoroethylene (m ⁵ ), structural unit M ⁶ is a structural unit derived from perfluoro (alkyl vinyl ether) (m ⁶ ), and structural unit N ³ is (It is a repeating unit derived from the monomer (m ³ ) and the monomer (n ³ ) copolymerizable with the monomer (m ⁶ ))

Among the perfluoro fluorine-containing rubbers represented by the general formula (11) (a-2) , the structural unit M ⁵ 50 to 90 mol%, preferably not containing a structural unit M ⁶ 10 to 50 mol%, more preferably structure unit M ⁵ 50 to 80 mol%, which comprises a structural unit M ⁶ 20 to 50 mol%, more preferably a structural unit M ⁵ 55 to 70 mol%, the structural unit M ⁶ 30-45 mole% containing It is a waste. The structural unit N ³ is preferably 0 to 5 mol%, more preferably 0 to 2 mol%, based on the total amount of the structural unit M ⁵ and the structural unit M ⁶ . When the composition is out of the range, the properties as a rubber elastic body are lost, and the properties tend to be similar to those of a resin.

Examples of perfluoro (alkyl vinyl ether) (m ⁶ ) include perfluoro (methyl vinyl ether) and perfluoro (propyl vinyl ether), and these can be used alone or in any combination.

The monomer (n ³ ) may be any monomer as long as it is copolymerizable with the monomer (m ⁵ ) and the monomer (m ⁶ ). preferable.

Examples of the monomer that gives such a crosslinking site include vinylidene fluoride, general formula (7):
CY ² ₂ = CY ³ −R _f ¹ CHR ³ X ⁴ (7)
Wherein Y ² is a hydrogen atom, fluorine atom or —CH ₃ , R _f ¹ is a fluoroalkylene group, perfluoroalkylene group, fluoropolyoxyalkylene group or perfluoropolyoxyalkylene group, and R ³ is hydrogen. Atom or —CH ₃ , X ⁴ is an iodine atom or a bromine atom), or an iodine or bromine-containing monomer represented by the general formula (8):
_{CF 2 = CFO (CF 2 CF} (CF 3) O) m (CF 2) n -X 5 (8)
(Wherein m is an integer of 0 to 5, n is an integer of 1 to 3, and X ⁵ is a cyano group, a carboxyl group, an alkoxycarbonyl group, a bromine atom, an iodine atom), General formula (9)
CH ₂ = CH (CF ₂ ) _n I (9)
(Wherein n is an integer of 1 to 10) and the like, and examples thereof include perfluoro (described in JP-B-5-63482 and JP-A-7-316234). Iodine-containing monomers such as 6,6-dihydro-6-iodo-3-oxa-1-hexene) and perfluoro (5-iodo-3-oxa-1-pentene), JP-A-4-505341 Bromine-containing monomer described, cyano group-containing monomer, carboxyl group-containing monomer, alkoxycarbonyl group-containing as described in JP-A-4-505345, JP-A-5-500070 And monomers. These can be used alone or in any combination.

  This iodine atom and bromine atom can introduce a vinyl group at the terminal by a dehalogenation reaction. In addition, a vinyl group, an iodine atom, a bromine atom, a cyano group, a carboxyl group, and an alkoxycarbonyl group can function as a crosslinking point.

  Specific examples of such perfluoro fluororubber (a-2) include International Publication No. 97/24381, Japanese Patent Publication No. 61-57324, Japanese Patent Publication No. 4-81608, Japanese Patent Publication No. 5-13961, and the like. Examples thereof include fluororubber described.

  The fluororubber (a) preferably has a number average molecular weight of 500 to 500,000, more preferably 1,000 to 500,000.

  On the other hand, it is preferable that the fluororubber (a) has fluidity at room temperature in that a molded product having a complicated shape can be easily obtained and on-site construction molds can be formed. The above “normal temperature” means 0 to 50 ° C.

  Specifically, the fluororubber (a) having fluidity at room temperature preferably has a viscosity at room temperature of 0.1 to 2000 Pa · s, and more preferably 1 to 1000 Pa · s. If the viscosity is less than 0.1 Pa · s, the polymer chain tends to be too short to be crosslinked, and if it exceeds 2000 Pa · s, it may not have fluidity at room temperature, and the molded product has a complicated shape. Tend to be difficult to obtain.

  Further, the fluororubber (a) having fluidity at room temperature preferably has a Mooney viscosity at room temperature of 5 to 100, and more preferably 50 to 75. If the Mooney viscosity is less than 5, the polymer chain tends to be too short to be crosslinked, and if it exceeds 100, it may not have fluidity at room temperature and it is difficult to obtain a molded product having a complicated shape. Tend to be. The Mooney viscosity is a value obtained by measurement using a Mooney viscometer MV2000 (manufactured by Monsanto) in accordance with JIS K 6300 (1994).

  And as for the fluororubber (a) which has fluidity at normal temperature, it is preferable that a number average molecular weight is 500-20000, and it is more preferable that it is 900-10000. If the number average molecular weight is less than 500, it tends to be difficult to form a three-dimensional network structure by crosslinking, and if it exceeds 20000, it may not have fluidity at room temperature, and a molded product having a complicated shape is obtained. Tend to be difficult. The number average molecular weight is a value determined by size exclusion chromatography (HLC-8020 manufactured by Tosoh Corporation, polystyrene standard).

The non-perfluorofluororubber (a-1) and the perfluorofluororubber (a-2) described above can be produced by a conventional method, but the obtained polymer has a narrow molecular weight distribution and the molecular weight can be easily controlled. From the point that iodine atoms can be introduced into the terminal, a known iodine transfer polymerization method is preferred as a method for producing fluororubber. For example, in a substantially oxygen-free manner, in the presence of an iodine compound, preferably a diiodine compound, a monomer constituting the fluorine-containing elastomer and, if necessary, a monomer that gives a crosslinking site are added under pressure. Examples thereof include a method of performing emulsion polymerization or solution polymerization in an aqueous medium in the presence of a radical initiator while stirring. As a representative example of the iodine compound to be used, for example, the general formula (12):
R ⁴ I _x Br _y (12)
(Wherein x and y are each an integer of 0 to 2 and satisfy 1 ≦ x + y ≦ 2, and R ⁴ is a saturated or unsaturated fluorohydrocarbon group having 1 to 16 carbon atoms or chlorofluoro A hydrocarbon group, or a hydrocarbon group having 1 to 3 carbon atoms, which may contain an oxygen atom). An iodine atom or a bromine atom is introduced into the terminal of the fluorine-containing elastomer obtained using such an iodine compound.

Examples of the compound represented by the general formula (12) include 1,3-diiodoperfluoropropane, 1,3-diiodo-2-chloroperfluoropropane, 1,4-diiodoperfluorobutane, 1,5. -Diiodo-2,4-dichloroperfluoropentane, 1,6-diiodoperfluorohexane, 1,8-diiodoperfluorooctane, 1,12-diiodoperfluorododecane, 1,16-diiodoperfluoro hexadecane, diiodomethane, 1,2-diiodoethane, 1,3-diiodo -n- _{propane, CF 2 Br 2, BrCF 2} CF 2 Br, CF 3 CFBrCF 2 Br, CFClBr 2, BrCF 2 CFClBr, CFBrClCFClBr, BrCF 2 CF 2 _{CF 2 Br, BrCF 2 CFBrOCF 3} , 1- bromo-2-iodo -Fluoroethane, 1-bromo-3-iodoperfluoropropane, 1-bromo-4-iodoperfluorobutane, 2-bromo-3-iodoperfluorobutane, 3-bromo-4-iodoperfluorobutene-1, 2- Bromo-4-iodoperfluorobutene-1, benzene monoiodomonobromo-substituted, diiodo-substituted, (2-iodoethyl) and (2-bromoethyl) -substituted, etc. They may be used or may be used in combination with each other.

  Among these, 1,4-diiodoperfluorobutane, diiodomethane, and the like are preferable from the viewpoints of polymerization reactivity, crosslinking reactivity, availability, and the like.

  The radical polymerization initiator used in the present invention may be the same as that conventionally used for the polymerization of fluorine-containing elastomers. These initiators include organic and inorganic peroxides and azo compounds. Typical initiators include persulfates, carbonate peroxides, peroxide esters and the like, and a preferred initiator is ammonium persulfate (APS). APS may be used alone or in combination with a reducing agent such as sulfites and sulfites.

  A wide range of emulsifiers can be used as the emulsion polymerization. From the viewpoint of suppressing the chain transfer reaction to the emulsifier molecule that occurs during the polymerization, the carboxylic acid having a fluorocarbon chain or a fluoropolyether chain is used. Salts are desirable. The amount of the emulsifier used is preferably about 0.05 to 2% by weight, more preferably 0.2 to 1.5% by weight, of the added water.

  The monomer mixed gas used in the present invention is explosive as described in GH Kalb et al., Advances in Chemistry Series., 129, 13 (1973). Therefore, it is necessary to devise a polymerization apparatus so as not to generate a spark or the like as an ignition source.

  The polymerization pressure can be varied within a wide range. Generally, it is the range of 0.5-7MPa. The higher the polymerization pressure, the higher the polymerization rate. Therefore, from the viewpoint of improving productivity, the polymerization pressure is preferably 0.8 MPa or more.

  The addition amount of the compound represented by the general formula (12) may be 0.0001 to 15% by weight based on the total weight of the obtained fluorine-containing elastomer.

  Furthermore, in the present invention, a composition containing fluororubber as described above can also be used.

  Next, alkali metals, alkaline earth metals, and transition metals will be described.

Alkali metal, alkaline earth metal, and transition metal act as a dehalogenating agent and are represented by the general formula (1) or the general formula (2) existing at the main chain terminal and / or the side chain terminal. Y ¹ Z is eliminated from the site by a dehalogenation reaction and converted to the site represented by the general formula (3). In addition, it is known that side reactions such as the formation of a hydrogen reductant occur along with the dehalogenation reaction depending on the setting of conditions such as the addition amount and the selection of the solvent.

  Among alkali metals, alkaline earth metals, and transition metals, alkali metals are strong in basicity and tend to deteriorate the fluorine-containing elastomer. Therefore, alkaline earth metals and transition metals are preferable, from the viewpoint of dehalogenation ability. In addition, transition metals having an atomic weight of 21-30, Mg, and Ca are preferable, and Mg, Cu, and Zn are more preferable because they are inexpensive and have high dehalogenation ability.

  The amount of alkali metal, alkaline earth metal, or transition metal added is preferably 1 to 50 times the molar amount of the site represented by the general formula (1) or (2) of the fluorine-containing elastomer. It is more preferable that the amount is ˜20 times the molar amount, and it is further more preferable that the amount is 5 to 20 times the molar amount because the fluorine-containing elastomer can be produced with a higher yield. If the amount is less than 1 times the molar amount, the dehalogenation reaction tends not to proceed sufficiently. If the amount exceeds 20 times the molar amount, the yield does not increase any more, and the cost of the metal reagent tends to increase. is there.

  In addition, as a solvent used for the dehalogenation reaction, a solvent having a low acidity, a solvent having a structure that hardly causes radical chain, a solvent having a high polarity, and a solvent having a low water content can be used because side reactions can be suppressed. In order to increase the reaction rate, it is more preferable to dissolve rubber.

  The solvent with low acidity preferably has a pKa of 6 or more, more preferably 10 or more, and even more preferably 14 or more.

  The solvent having a high polarity is preferably one having a dielectric constant of 2 or more, more preferably 5 or more.

  As the solvent having a structure that hardly causes radical chaining, a solvent having a structure that does not have a hydrogen atom that is easily extracted by a radical reaction is preferable.

  Specifically, alcohols are preferable from the viewpoint of rubber solubility and radical stability, and nitriles, ketones, esters, and ethers are preferable from the viewpoint of rubber solubility, radical stability, and low pKa. Nitriles are preferable.

  As the alcohols, alcohols having 15 or less carbon atoms are preferable and alcohols having 7 or less carbon atoms are more preferable from the viewpoint of rubber solubility and radical stability. Specific examples include methanol, ethanol, propanol, isopropanol, butanol, t-butanol, phenol, and the like. Among these, methanol is preferable from the viewpoint of rubber solubility.

  Nitriles are preferably those having 10 or less carbon atoms, more preferably those having 8 or less carbon atoms, from the viewpoint of rubber solubility and radical stability. Specific examples include acetonitrile, ethyl cyanide, butyronitrile, butyl cyanide, and benzonitrile. Among these, acetonitrile is preferable because of its high rubber solubility.

  The ketones are preferably those having 10 or less carbon atoms, more preferably those having 6 or less carbon atoms, from the viewpoint of rubber solubility and radical stability. Specific examples include acetone, dimethyl ketone, methyl ethyl ketone, diethyl ketone, and cyclohexanone.

  Esters are preferably those having 10 or less carbon atoms, more preferably those having 6 or less carbon atoms, from the viewpoint of rubber solubility and radical stability. Specific examples include methyl acetate, ethyl acetate, butyl acetate, propyl acetate and the like.

  The ethers are preferably those having 10 or less carbon atoms, more preferably those having 6 or less carbon atoms, from the viewpoint of rubber solubility and radical stability. Specific examples include tetrahydrofuran, monoglyme, diglyme, and tetraglyme.

  The addition amount of the solvent is not particularly limited, but is preferably 500 to 5000 parts by weight with respect to 100 parts by weight of the fluorine-containing elastomer.

  The reaction conditions may be appropriately selected according to the type of fluorine-containing elastomer, alkali metal, alkaline earth metal, transition metal, solvent, etc., but may be reacted at 50 to 100 ° C. for 1 to 24 hours. preferable.

  In the fluorine-containing elastomer having the site represented by the general formula (3) obtained by the dehalogenation reaction, the ratio of the unsaturated group to the terminal is preferably 50% or more and 70% when both terminals are used in the reaction. The above is more preferable, and 90% or more is more preferable. When one end is used for the reaction, 70% or more of the one end is preferable, 80% or more is more preferable, and 90% or more is more preferable. When the ratio of the unsaturated group is outside this range, there is a tendency that sufficient crosslinking cannot be performed when the obtained fluorine-containing elastomer is crosslinked.

  In the present invention, an oxidizing agent is allowed to act on the fluorine-containing elastomer having the site represented by the general formula (3) obtained by the dehalogenation reaction, so that the site represented by the general formula (3) is converted to —COOH. A step of converting can also be included.

  The oxidizing agent is not particularly limited. For example, any oxidizing agent described in, for example, the Chemical Society of Japan, 5th edition, Experimental Chemistry Course Vol. 17, 2004 Maruzen Co., Ltd. can be used. Specifically, hypochlorite, chromic acid, manganese compound, osmium tetroxide, ruthenium tetroxide, copper compound, palladium compound, iron compound, vanadium compound, metal oxide, oxygen, ozone, etc. are preferable, chromic acid Permanganate, activated manganese dioxide, manganese (III) salt, osmium tetroxide, and ruthenium tetroxide are more preferred.

  The addition amount of the oxidizing agent is preferably 1 to 50 times the molar amount, more preferably 2 to 50 times the molar amount of the site represented by the general formula (3) of the fluorine-containing elastomer, From the viewpoint of high conversion efficiency to —COOH, the molar amount is more preferably 5 to 20 times. If the amount is less than 1 times the molar amount, the oxidation reaction tends not to proceed sufficiently. If the amount exceeds 50 times the molar amount, only the cost of the oxidizing agent is increased and there is no merit.

  As reaction conditions, optimal conditions may be selected as appropriate depending on the type of fluorine-containing elastomer, oxidizing agent, solvent, etc., but it is preferable to react at room temperature to 100 ° C. for 1 to 20 hours.

Thus, as a fluorine-containing elastomer converted into the site | part shown by General formula (3) obtained by the manufacturing method of this invention, for example, General formula (4):
B _a- (M)-(A) -C _b (4)
Is a novel substance that is unknown in the literature.

  In the formula, M is a structural unit derived from vinylidene fluoride and / or tetrafluoroethylene, and any of the above-mentioned fluorine-containing elastomers can be used more suitably.

  A may be any structural unit derived from an ethylenic monomer copolymerizable with M. For example, chlorotrifluoroethylene (CTFE), trifluoroethylene, hexafluoropropylene (HFP), Fluorinated monomers such as fluoropropylene, tetrafluoropropylene, pentafluoropropylene, trifluorobutene, tetrafluoroisobutene, perfluoro (alkyl vinyl ether) (PAVE), vinyl fluoride, ethylene, propylene, alkyl vinyl ether, etc. .

B and C are the same or different,
General formula (5):

It is group shown by these.

  a and b are each 0 or 1, and a + b ≠ 0. When a and b are each 0, as the terminal of the fluorine-containing elastomer represented by the general formula (4), the general formula (13a):

General formula (13b):

Or a group selected from the group consisting of a chain transfer residue or an initiator end.

In the formula, Y ³ is a hydrogen atom, a bromine atom, a chlorine atom or an iodine atom.

R ² is an alkylene group that may contain an ether bond having 1 to 5 carbon atoms, and part or all of the hydrogen atoms may be substituted with fluorine atoms.

  n is an integer of 0 or more, and 0 is preferable. Although it does not specifically limit as an upper limit, It is preferable that it is 5 or less.

The chain transfer residue is the structure of the polymer terminal derived from the chain transfer agent used for the synthesis of the fluorine-containing elastomer. The chain transfer terminal is terminated by the chain transfer agent, and the chain transfer is terminated by the polymerization growth terminal. comprise a terminal of the polymer polymerization is restarted from the dosage, for _{example, -CF 3, -CF 2 CF 3} , -CF 2 CF 2 CF 2 CF 2 COOH, -CF (CF 3) 2, -CF 2 CF 2 H , —CF ₂ CH ₃ , —CH ₂ CF ₂ H, and the like.

The initiator terminal is the structure of the polymer terminal derived from the polymerization initiator used for the synthesis of the fluorine-containing elastomer, and the structure of the polymerization initiator or the monomer constituting the polymerization initiator and the fluorine-containing elastomer reacted. It includes a structure, _{e.g., -CF 2 CH 2 OH, -CH} 2 COOH, -CF 2 COOH, -CF 2 COOD, ( the D, NH _4, or, Na, alkali metals such as K) -CH ₂ COOD etc. Can be given.

  Among these groups, as the fluorine-containing elastomer of the present invention, those having a group represented by the general formula (5) are preferable.

  The fluorine-containing elastomer represented by the general formula (4) is preferably obtained by the production method described above.

  Moreover, it is preferable that the number average molecular weights of a fluorine-containing elastomer are 500-500000, and it is more preferable that it is 3000-500000. When the number average molecular weight is less than 500, the crosslinking density tends to be excessively increased when a terminal-based curing reaction is performed. When the number average molecular weight exceeds 500,000, the viscosity of the fluorine-containing elastomer is too high and mixing with the crosslinking agent becomes difficult. Tend.

  Next, the curable composition of this invention is demonstrated.

  The curable composition of the present invention is sufficiently cross-linked to contain a compound capable of undergoing a cross-linking reaction with the fluorine-containing elastomer having a site represented by the general formula (3) at the main chain end and / or side chain end. This is preferable from the viewpoint of obtaining a cured product.

  As the compound capable of crosslinking reaction, a polyfunctional compound having a plurality of functional groups capable of reacting with the fluorine-containing elastomer in the molecule is preferably exemplified. As the polyfunctional compound, it is preferable to use a polyfunctional compound having at least 2 functional groups per molecule and, if necessary, 3 or more from the viewpoint of sufficient crosslinking.

  Moreover, in order for a curable composition to fully bridge | crosslink, it is preferable to use the polyfunctional compound according to the crosslinked part which the said fluorine-containing elastomer has. Hereinafter, although the specific example of this polyfunctional compound is given, this polyfunctional compound may use 1 type (s) or 2 or more types.

  When the crosslinkable site is a hydrocarbon group having 2 to 10 carbon atoms having at least one unsaturated bond, examples of the polyfunctional compound include a compound having a —SiH group and a polyfunctional unsaturated compound.

  When peroxide crosslinking is performed using an organic peroxide, the elastomer of the present invention does not have iodine at the end compared to the conventional elastomer containing iodine at the end, so that no iodine-containing compound is generated during crosslinking. preferable.

  When the crosslinking site is a -COOH group, preferred examples of the polyfunctional compound include polyamine compounds, polyisocyanate compounds, polyepoxy compounds, polyaminophenol compounds, polyaminothiophenol compounds, and the like.

  Examples of the polyamine compound include polyamines such as hexamethylenediamine, triethylenetetramine, and triethylenediamine; combined use of a polyamine salt and a guanidine derivative.

  Examples of the polyisocyanate compound include tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate and the like. The polyisocyanate compound may be a block type capable of selecting a prepolymer and a crosslinking temperature.

  Examples of the polyepoxy compound include novolak type, bisphenol A type, and bisphenol AF type. The polyepoxy compound may be a prepolymer.

  As the polyaminophenol compound, polyaminothiophenol compound, and polyamine compound, the general formula (14):

(Wherein X ⁶ is —OH, —SH, —NH ₂ , R ⁵ is a hydrocarbon group having 1 to 10 carbon atoms, and n is an integer of 2 to 5).

  In addition, when the crosslinking site is a hydrocarbon group having 2 to 10 carbon atoms having at least one unsaturated bond, the unsaturated bond can contribute to the three-dimensional network structure by hydrosilylation reaction. Especially as a compound, it is preferable that it is a compound which has a 2 or more Si-H group.

The compound having two or more —SiH groups is generally represented by the general formula (15):
R ⁶ _b H _c SiO _{(4-bc) / 2} (15)
In the formula, R ⁶ is a substituted or unsubstituted monovalent hydrocarbon group having 1 to 10 carbon atoms, particularly 1 to 8 carbon atoms, excluding an aliphatic unsaturated bond. Examples of such a monovalent hydrocarbon group include an alkyl group substituted with a halogen such as a trifluoropropyl group, an alkyl group, and a phenyl group. Among these, a methyl group, an ethyl group, a propyl group, a phenyl group, and a trifluoropropyl group are preferable, and a methyl group and a phenyl group are particularly preferable.

  In the general formula (15), b is preferably 0 ≦ b <3, more preferably 0.6 <b <2.2, and further preferably 1.5 ≦ b ≦ 2. , C is preferably 0 <c ≦ 3, more preferably 0.002 ≦ c <2, and still more preferably 0.01 ≦ c ≦ 1. Further, b + c is preferably 0 <b + c ≦ 3, and more preferably 1.5 <b + c ≦ 2.7.

The compound having two or more —SiH groups is preferably an organohydrogenpolysiloxane having 1 to 1000 silicon atoms, more preferably 2 to 300 silicon atoms, and further preferably 4 to 200 silicon atoms in one molecule. Yes, specifically 1,1,3,3-tetramethyldisiloxane, 1,3,5-trimethylcyclotrisiloxane, 1,3,5,7-tetramethylcyclotetrasiloxane, 1,3,5 , 7,9-Pentamethylcyclopentasiloxane, etc .; molecular chain both ends trimethylsiloxy group-blocked methylhydrogen polysiloxane, molecular chain both ends trimethylsiloxy group-blocked dimethylsiloxane / methylhydrogensiloxane copolymer, molecular chain Both ends silanol-blocked methyl hydrogen polysiloxane, both molecular chains End silanol group-blocked dimethylsiloxane / methylhydrogensiloxane copolymer, molecular chain both ends dimethylhydrogensiloxy group-blocked dimethylpolysiloxane, molecular chain both ends dimethylhydrogensiloxy group-blocked methylhydrogenpolysiloxane, molecular chain both ends dimethyl Hydrogensiloxy group-blocked dimethylsiloxane / methylhydrogensiloxane copolymer, comprising R ⁶ ₂ (H) SiO _1/2 units and SiO _4/2 units, optionally R ⁶ ₃ SiO _1/2 units, R ⁶ _Examples thereof include silicone resins containing ₂ SiO _2/2 units, R ⁶ (H) SiO _2/2 units, (H) SiO _3/2 units, or R ⁶ SiO _3/2 units.

  Examples of the methyl hydrogen polysiloxane blocked with trimethylsiloxy groups at both ends of the molecular chain include, for example, a compound represented by the general formula (16), wherein a part or all of the methyl groups in the general formula (16) are ethyl, propyl, phenyl And a compound substituted with a trifluoropropyl group.

(In the formula, d represents an integer of 2 or more.)

  The trimethylsiloxy group-blocked dimethylsiloxane / methylhydrogensiloxane copolymer at both molecular chain terminals is a compound represented by the general formula (17), wherein a part or all of the methyl groups in the general formula (17) are ethyl or propyl. And compounds substituted with a group, phenyl group, trifluoropropyl group, and the like.

(In the formula, e represents an integer of 1 or more, and f represents an integer of 2 or more.)

  Examples of the silanol group-blocked methyl hydrogen polysiloxane having both molecular chain ends include, for example, a compound represented by the following formula, and in the following formula, part or all of the methyl group is an ethyl group, a propyl group, a phenyl group, a trifluoropropyl group, etc. Examples thereof include substituted compounds.

  Examples of the dimethylsiloxane / methylhydrogensiloxane copolymer blocked with silanol groups at both ends of the molecular chain include, for example, a compound represented by the general formula (18), a part or all of the methyl groups in the general formula (18) being ethyl group, propyl And compounds substituted with a group, phenyl group, trifluoropropyl group, and the like.

(In the formula, e represents an integer of 1 or more, and f represents an integer of 2 or more.)

  Examples of the dimethylpolysiloxane blocked with a dimethylhydrogensiloxy group at both ends of the molecular chain include, for example, a compound represented by the general formula (19), and a part or all of the methyl groups in the general formula (19) are ethyl, propyl, phenyl And a compound substituted with a trifluoropropyl group.

(In the formula, e represents an integer of 1 or more.)

  Examples of the dimethylhydrogensiloxy group-blocked methylhydrogenpolysiloxane having both molecular chain terminals include, for example, a compound represented by the general formula (20), a part or all of the methyl groups in the general formula (20), an ethyl group, a propyl group, Examples thereof include compounds substituted with a phenyl group, a trifluoropropyl group, and the like.

(In the formula, e represents an integer of 1 or more.)

  Examples of the dimethylhydrogensiloxy group-blocked dimethylsiloxane / methylhydrogensiloxane copolymer having both ends of the molecular chain include a compound represented by the general formula (21), a part or all of the methyl groups in the general formula (21) being ethyl And compounds substituted with a group, a propyl group, a phenyl group, a trifluoropropyl group, and the like.

(In the formula, g and h each represent an integer of 1 or more.)

  Such a compound can be produced by a known method, for example, a compound containing octamethylcyclotetrasiloxane and / or tetramethylcyclotetrasiloxane and a triorganosilyl group or diorganohydrogensiloxy group which can be a terminal group. Can be easily obtained by equilibrating at a temperature of about −10 to 40 ° C. in the presence of a catalyst such as sulfuric acid, trifluoromethanesulfonic acid or methanesulfonic acid. Examples of the compound containing a triorganosilyl group include hexamethyldisiloxane, and examples of the compound containing a diorganohydrogensiloxy group include 1,3-dihydro-1,1,3,3-tetra. Examples thereof include methyldisiloxane.

  In consideration of compatibility with the fluorine-containing elastomer of the present invention, dispersibility, and uniformity after crosslinking, the compound having two or more Si-H groups in one molecule is one or more in one molecule. Having a monovalent perfluorooxyalkyl group, a monovalent perfluoroalkyl group, a divalent perfluorooxyalkylene group, or a divalent perfluoroalkylene group, and two or more, preferably three or more Those having Si-H groups are preferred. Examples of the perfluorooxyalkyl group, perfluoroalkyl group, perfluorooxyalkylene group, and perfluoroalkylene group include those represented by the following general formula.

As the monovalent perfluoroalkyl group, the general formula (22):
C _k F _{2k + 1} − (22)
(Wherein k represents an integer of 1-20, preferably 2-10),
As the divalent perfluoroalkylene group, the general formula (23):
−C _k F _2k − (23)
(Wherein k represents an integer of 1 to 20, preferably 2 to 10),
As the monovalent perfluorooxyalkyl group, the general formula (24) or (25):

(In the formula, n represents an integer of 1 to 5.)

  As the divalent perfluorooxyalkylene group, the general formula (26):

(In the formula, m represents an integer of 1 to 50, n represents an integer of 1 to 50, m + n satisfies 2 to 100), or General Formula (27):
_{- (CF 2 O) m -} (CF 2 CF 2 O) n -CF 2 - (27)
(In the formula, m and n each represent an integer of 1 to 50.)
As the divalent linking group for connecting the perfluoroalkyl group, perfluorooxyalkyl group, perfluoroalkylene group or perfluorooxyalkylene group and a silicon atom, an alkylene group, an arylene group, an alkylene group and an arylene group are combined. A group in which an ether bond oxygen atom, an amide bond, a carbonyl bond or the like is interposed in these groups, for example, —CH ₂ CH ₂ —, —CH ₂ CH ₂ CH ₂ —, —CH _{2 CH 2 CH 2 OCH 2 -,} - CH 2 CH 2 CH 2 -NH-CO -, - CH 2 CH 2 CH 2 -N (Ph) -CO-, ( wherein, Ph represents a phenyl group.) Examples thereof include those having 2 to 12 carbon atoms such as —CH ₂ CH ₂ CH ₂ —N (CH ₃ ) —CO— and —CH ₂ CH ₂ CH ₂ —O—CO—.

  In addition, the monovalent or divalent fluorine-containing substituent in the compound having two or more —SiH groups in one molecule, that is, a perfluoroalkyl group, a perfluorooxyalkyl group, a perfluoroalkylene group, or a perfluorooxy group. Examples of the monovalent substituent bonded to the silicon atom other than the monovalent organic group containing an alkylene group include a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, a cyclohexyl group, an octyl group, and a decyl group. Alkyl groups such as vinyl groups and allyl groups; aryl groups such as phenyl groups, tolyl groups and naphthyl groups; aralkyl groups such as benzyl groups and phenylethyl groups; and at least some of the hydrogen atoms of these groups Substituted with chlorine atom, cyano group, etc., for example chloromethyl group, chloropropyl group, cyano Unsubstituted or substituted hydrocarbon group having 1 to 20 carbon atoms such as methyl group and the like.

  The compound having two or more —SiH groups in one molecule may be any of cyclic, chain, three-dimensional network, or a combination thereof. The number of silicon atoms in the compound having two or more —SiH groups in one molecule is not particularly limited, but is usually 2 to 60, preferably 3 to 60, and more preferably 3 to 30.

  Examples of the compound having two or more —SiH groups in one molecule include the following compounds. In the following formulae, Me represents a methyl group and Ph represents a phenyl group. In addition, these compounds can be used individually by 1 type or in combination of 2 or more types.

(In the formula, m represents an integer of 1 to 20 and an average of 10, and n represents an integer of 1 to 10 and an average of 6.)

(Where S is

N represents an integer of 1 to 30, and m represents an integer of 1 to 30. n + m satisfies 2 to 60 and an average of 2 to 50. )

(Where S is

N represents an integer of 1 to 30, and m represents an integer of 1 to 30. n + m satisfies 2 to 60 and an average of 2 to 50. )

(In the formula, n represents an integer of 2 to 60 and an average of 3 to 50.)

(In the formula, n represents an integer of 2 to 60 and an average of 3 to 50.)

(In the formula, n represents an integer of 2 to 60 and an average of 3 to 50.)

  Moreover, the curable composition containing the fluorine-containing elastomer whose crosslinking site is a C2-C10 hydrocarbon group having at least one unsaturated bond and a compound having two or more Si-H groups in one molecule. In this case, it is preferable to add a hydrosilylation reaction catalyst from the viewpoint of the reactivity of the hydrosilylation reaction.

  The hydrosilylation reaction catalyst is not particularly limited as long as it promotes an addition reaction (alkene hydrosilylation reaction) between a fluorine-containing elastomer and a compound having two or more Si-H groups in one molecule. An addition reaction catalyst (group 8 metal catalyst such as group 8 metal, group 8 metal complex, group 8 metal compound, etc.) of platinum group elements such as platinum catalyst, palladium catalyst, rhodium catalyst, etc. Among them, a platinum-based catalyst is preferable because it is relatively easy to obtain.

  The platinum-based catalyst may be a known one that is usually used for addition-curing type curing, such as a finely powdered platinum metal catalyst described in US Pat. No. 2,970,150, US Pat. No. 2,823, No. 218, chloroplatinic acid catalyst, platinum and hydrocarbon complex compounds described in US Pat. No. 3,159,601 and US Pat. No. 159,662, US Pat. Complexes of chloroplatinic acid and olefins described in US Pat. No. 516,946, platinum and vinylsiloxane described in US Pat. No. 3,775,452 and US Pat. No. 3,814,780 And the complex compounds. More specifically, platinum alone (platinum black); chloroplatinic acid; a complex of chloroplatinic acid and an olefin such as ethylene; a complex of chloroplatinic acid and an alcohol or vinylsiloxane; a carrier such as silica, alumina or carbon For example, platinum supported thereon.

The palladium-based catalyst is composed of palladium, palladium compound, chloropalladic acid, and the rhodium-based catalyst is composed of rhodium, rhodium compound, rhodium chloride, and the like. For example, RhCl (PPh ₃ ) ₃ , RhCl (CO ) (PPh ₃ ) ₂ , RhCl (C ₂ H ₄ ) ₂ , Ru ₃ (CO) ₁₂ , IrCl (CO) (PPh ₃ ) ₂ , Pd (PPh ₃ ) ₄ (Ph represents a phenyl group), etc. Can be given.

  The hydrosilylation reaction catalyst may also be a Lewis acid, cobalt carbonyl, or the like.

  Moreover, it is preferable to use a reaction inhibitor. Examples of the reaction inhibitor include benzotriazole; acrylonitrile; N, N-diallylacetamide, N, N-diallylbenzamide, N, N, N ′, N′-tetraallyl-o-phthalic acid diamide, N, N, N. Amide compounds such as ', N'-tetraallyl-m-phthalic acid diamide, N, N, N', N'-tetraallyl-p-phthalic acid diamide; sulfur; phosphorus; nitrogen; amine compound; sulfur compound; Tin; tin compound; tetramethyltetravinylcyclotetrasiloxane; and organic peroxides such as hydroperoxide.

  Examples of the reaction inhibitor include 1-ethynyl-1-hydroxycyclohexane, 3-methyl-1-butyn-3-ol, 3,5-dimethyl-1-hexyn-3-ol, and phenylbutynol. Of acetylene alcohol, 3-methyl-3-penten-1-yne, 3,5-dimethyl-3-hexen-1-yne, 3-methyl-1-penten-3-ol, US Pat. No. 3,445,420 It may be an acetylene compound such as a compound exemplified as the compound (4) in the specification and a compound exemplified as the component (d) in JP-B-54-3774.

  The amount of the compound capable of undergoing a crosslinking reaction with the crosslinking site of the fluorine-containing elastomer of the present invention is preferably 0.05 to 10 parts by weight, and 0.5 to 5 parts by weight with respect to 100 parts by weight of the fluorine-containing elastomer. It is more preferable that If the amount is less than 0.05 parts by weight, the crosslinking cannot be sufficiently performed. If the amount exceeds 10 parts by weight, the crosslinking reaction tends to proceed only to an extent corresponding to the amount added.

  In the curable composition of the present invention, an acid acceptor may be added in advance in order to accelerate the reaction. Examples of the acid acceptor include metal oxides such as magnesium oxide, calcium oxide, silicon oxide, aluminum oxide, and lead oxide; metal hydroxides such as magnesium hydroxide, calcium hydroxide, and aluminum hydroxide; synthetic hydrotalcite, etc. Can be used. It is preferable that the usage-amount of an acid acceptor is 1-30 weight part with respect to 100 weight part of fluorine-containing elastomers.

  In addition, the curable composition of the present invention may also contain other fluorine-containing elastomers that are not included in the fluorine-containing elastomer obtained by the production method of the present invention described above, from the viewpoint that a function as a processing aid can be expected. Good.

  The curable composition of the present invention is a conventional additive blended in the curable composition containing a fluorine-containing elastomer as necessary, for example, a filler, a processing aid, a plasticizer, a colorant, an antioxidant. , Anti-aging agents, ozone degrading agents, ultraviolet absorbers and the like can be blended, and one or more conventional crosslinking agents and crosslinking aids different from those mentioned above may be blended, It can prepare by mixing using a normal elastomer processing machine, for example, an open roll, a Banbury mixer, a kneader. In addition, it can be prepared by a method using a closed mixer or a method of co-coagulation from emulsion mixing. The curable composition thus obtained is crosslinked and molded according to a conventional method. That is, it is molded by compression molding, injection molding, extrusion molding, calendar molding, dip molding, coating, etc. by dissolving in a solvent.

  The crosslinking conditions vary depending on the molding method and the shape of the molded product, but are generally in the range of several seconds to 5 hours at 100 ° C to 300 ° C. Further, secondary crosslinking may be performed in order to stabilize the physical properties of the crosslinked product. Secondary crosslinking conditions are 150 to 300 ° C. and about 30 minutes to 48 hours.

  Moreover, what is necessary is just to mix with a planetary mixer or a tabletop mixer, when the fluorine-containing elastomer obtained by the manufacturing method of this invention is low molecular weight and has fluidity | liquidity at normal temperature. At this time, the temperature may be raised to 50 ° C. or higher in order to promote the reaction. Furthermore, the curable composition is preferably reacted at a temperature of 50 ° C. or higher for 3 hours or longer.

  The curable composition having fluidity at room temperature is usually processed at a temperature of 200 ° C. or less by an extrusion gun such as a hot melt gun, injection molding or extrusion molding by a LIMS (Liquid Injection Molding System) molding machine, room temperature to 200 ° C. The molding performed by pouring into a mold can be performed.

  As a method for crosslinking the curable composition, a method other than the above can be used depending on the type of the crosslinking site.

  The molded article of the present invention can be suitably used in the following fields.

  In semiconductor-related fields such as semiconductor manufacturing equipment, liquid crystal panel manufacturing equipment, plasma panel manufacturing equipment, plasma addressed liquid crystal panels, field emission display panels, solar cell substrates, etc., O (square) rings, packing, sealing materials, tubes, rolls, coatings Linings, gaskets, diaphragms, hoses, etc. These include CVD equipment, dry etching equipment, wet etching equipment, oxidation diffusion equipment, sputtering equipment, ashing equipment, cleaning equipment, ion implantation equipment, exhaust equipment, chemical piping, gas Can be used for piping. Specifically, as a gate valve O-ring, seal material, quartz window O-ring, seal material, chamber O-ring, seal material, gate O-ring, seal material, bell jar O-ring, seal material As an O-ring for a coupling, as a sealing material, as an O-ring for a pump, as a sealing material, as a diaphragm, as an O-ring for a semiconductor gas control device, as a sealing material, as an O-ring for a resist developer and as a stripping solution As a wafer cleaning solution hose and tube, as a wafer transfer roll, as a resist developer bath, a stripping solution bath lining, as a coating, as a wafer cleaning bath lining, as a coating or as a wet etching bath lining, as a coating Can do. In addition, sealing materials and sealants, optical fiber quartz coatings, electronic parts for insulation, vibration proofing, waterproofing and moisture proofing, circuit board potting, coating, adhesive sealing, gaskets for magnetic storage devices, epoxies, etc. Used as a sealing material modifier, sealant for clean rooms and clean facilities, etc.

  In the automotive field, gaskets, shaft seals, valve stem seals, sealing materials and hoses can be used for engines and peripheral devices, hoses and sealing materials can be used for AT devices, O (square) rings, tubes, packings. The valve core material, hose, sealing material and diaphragm can be used for fuel systems and peripheral devices. Specifically, engine head gasket, metal gasket, oil pan gasket, crankshaft seal, camshaft seal, valve stem seal, manifold packing, oil hose, oxygen sensor seal, ATF hose, injector O-ring, injector packing, fuel Pump O-ring, diaphragm, fuel hose, crankshaft seal, gearbox seal, power piston seal, cylinder liner seal, valve stem seal, automatic transmission front pump seal, rear axle pinion seal, universal joint gasket, speed Meter pinion seal, foot brake piston cup, torque transmission O-ring, oil seal, exhaust gas reburner seal, bearing Lumpur, EGR tubes, Tsuinkyabu tube, the sensor diaphragm of the carburetor, rubber vibration isolator (engine mount, exhaust part, etc.), afterburners hoses, can be used as an oxygen sensor bush.

  In the aircraft field, the rocket field, and the marine field, there are diaphragms, O (square) rings, valves, tubes, packings, hoses, sealing materials, and the like, which can be used for fuel systems. Specifically, in the aircraft field, it is used for jet engine valve steal seals, fuel supply hoses, gaskets and O-rings, rotating shaft seals, hydraulic equipment gaskets, firewall seals, etc. Used for propeller shaft stern seal, diesel engine intake / exhaust valve stem seal, butterfly valve seal, butterfly valve shaft seal, etc.

  In the field of chemical products such as plants, linings, valves, packing, rolls, hoses, diaphragms, O (square) rings, tubes, sealing materials, chemical-resistant coatings, etc., these include pharmaceuticals, agricultural chemicals, paints, resins, etc. It can be used in chemical manufacturing processes. Specifically, chemical pumps, rheometers, pipe seals, heat exchanger seals, glass cooler packing of sulfuric acid production equipment, pesticide sprayers, pesticide transfer pump seals, gas pipe seals, plating solutions Seals, packing for high-temperature vacuum dryers, roller seals for papermaking belts, fuel cell seals, wind tunnel joint seals, rolls for trichrene (for fiber dyeing), acid-resistant hoses (for concentrated sulfuric acid), gas chromatography, pH meter It can be used as packing for tube joints, chlorine gas transfer hoses, benzene, rainwater drain hoses for toluene storage tanks, seals for analytical instruments, physics and chemistry instruments, tubes, diaphragms, valve parts, and the like.

  In the pharmaceutical field such as pharmaceuticals, it can be used as a medicine stopper.

  In the photographic field such as a developing machine, the printing field such as a printing machine, and the coating field such as a coating facility, there are rolls and the like, which can be used for a film developing machine, an X-ray film developing machine, a printing roll, and a coating roll, respectively. Specifically, as a developing roll of a film developing machine / X-ray film developing machine, a gravure roll of a printing roll, a guide roll, a gravure roll of a magnetic tape manufacturing coating line of a coating roll, a guide of a magnetic tape manufacturing coating line It can be used as a roll, various coating rolls, and the like. Furthermore, dry copying machine seals, printing equipment printing rolls, scrapers, tubes, valve parts, coating, coating equipment coating rolls, scrapers, tubes, valve parts, printer ink tubes, rolls, belts, dry copying machine belts , Rolls, printing press rolls, belts, and the like.

  Tubes can also be used in the field of analysis and physics and chemistry.

  In the field of food plant equipment, linings, valves, packings, rolls, hoses, diaphragms, O (square) rings, tubes, sealing materials, belts and the like can be mentioned and used in food production processes. Specifically, it can be used as a seal for a plate heat exchanger, a solenoid valve seal for a vending machine, or the like.

  In the field of nuclear plant equipment, packing, O-rings, hoses, sealing materials, diaphragms, valves, rolls, tubes and the like can be mentioned.

  In the steel field such as iron plate processing equipment, rolls and the like can be mentioned, and the steel plate processing rolls can be used.

  In general industrial fields, packing, O-rings, hoses, sealing materials, diaphragms, valves, rolls, tubes, linings, mandrels, electric wires, flexible joints, belts, rubber plates, weather strips, rolls for PPC copiers, roll blades, belts Etc. Specifically, oil pressure, lubrication machine seals, bearing seals, dry cleaning equipment windows, other seals, uranium hexafluoride concentrator seals, cyclotron seal (vacuum) valves, automatic packaging machine seals, air It is used for diaphragms (pollution measuring devices) for analysis of sulfurous acid gas and chlorine gas in the inside, rolls for printing presses, belts, pickling rolls for pickling.

  In the electric field, specifically, it is used as an insulating oil cap for Shinkansen, a bench seal for a liquid seal transformer, a jacket for an oil well cable, and the like.

  In the fuel cell field, specifically, it is used as a sealing material between electrodes and separators, a seal for hydrogen / oxygen / product water piping, and the like.

  Specifically, in the field of electronic components, it is used as a heat radiation material, an electromagnetic shielding material, a modified material of a printed wiring board prepreg resin such as epoxy, an anti-scattering material such as a light bulb, and a gasket of a hard disk drive of a computer.

  There are no particular limitations on what can be used for on-site molding, such as metal gasket coatings for automobile engines, engine oil pan gaskets, copier / printer rolls, architectural sealants, Gaskets for magnetic recording devices, sealants for filter units for clean rooms, coating agents for printed boards, fixing agents for electrical and electronic components, insulation and moisture-proof treatment of electrical equipment lead wire terminals, oven seals for electric furnaces, sheathed heaters Examples include end treatment, microwave window frame seal, CRT wedge and neck adhesion, automotive electrical component adhesion, joint seals for kitchens, bathrooms, washrooms, and the like.

  The curable composition of the present invention is particularly suitable for a sealing material for clean equipment such as a gasket for a magnetic recording device (hard disk drive), a sealing material for a device storage such as a semiconductor manufacturing apparatus or a wafer, etc., taking advantage of cleanliness. Used.

  The curable composition of the present invention utilizes characteristics such as chemical resistance, low gas permeability, flame retardancy, etc., and seals for fuel cells such as packing used between fuel cell electrode electrodes and surrounding pipes, etc. Also particularly preferably used.

  Next, the present invention will be described with reference to examples, but the present invention is not limited to such examples.

Reference example 1
(Polymerization of fluorine-containing elastomer)
A polymerization tank having an internal volume of 3.0 liters having a magnetic induction stirrer was supplied with 1.47 L of pure water and 30 g of an aqueous 10% by weight ammonium perfluorooctanoate solution. After sufficiently replacing the system with nitrogen gas and then reducing the pressure, the internal temperature was raised to 80 ° C., HFP was charged to an internal pressure of 0.73 MPa, and VdF was charged to 1.5 MPa. Under stirring, 0.114 g of ammonium persulfate (APS) was dissolved in 8.1 g of water and charged to initiate polymerization. The polymerization pressure was set to 1.5 MPa, and in order to compensate for the pressure drop during polymerization, VdF / HFP mixed monomer (78/22 (mol%)) was continuously supplied, and 300 g of monomer was put into the tank until the polymerization was completed. Supplied. In the middle, when 7 g of the VdF / HFP mixed monomer was supplied, 22.7 g of octafluoro-1,4-diiodobutane and 0.114 g of APS were dissolved in 8.1 g of water 3 hours and 6 hours after the start of polymerization, respectively. Additional aqueous solution was charged. The reaction time was 10 hours and 1 minute. The weight of the obtained emulsion was 1851 g, and the polymer concentration was 17.7% by weight.

This emulsion was coagulated with an aluminum sulfate aqueous solution and then washed with warm water to obtain a viscous fluorine-containing elastomer. The copolymer composition ratio of the obtained fluorine-containing elastomer was VdF / HFP = 77.5 / 22.5 (mol%) as measured by ¹⁹ F-NMR. The molecular weight in terms of polystyrene as measured by GPC was a weight average molecular weight of 10760 and a number average molecular weight of 8600. In ¹ H-NMR analysis with a heavy acetone solvent, peaks of 3.97, 3.91, 3.85, 3.78 ppm derived from the terminal structure —CF ₂ CH ₂ I were observed. The ratio between the intensity of this peak and the intensity of the peak derived from the main chain —CH ₂ — of the fluorine-containing elastomer was 1:34.

Example 1
7.75 g of the fluorine-containing elastomer obtained in Reference Example 1 was dissolved in 100 g of anhydrous acetonitrile under water-free conditions in a four-necked flask equipped with a reflux condenser, and further zinc powder (first grade, Kishida Chemical Co., Ltd.) (Manufactured) 0.73 g (5.6-fold molar amount with respect to the —CF ₂ CH ₂ I content of the fluorine-containing elastomer) was supplied, followed by heating for 18 hours with stirring to reflux acetonitrile.

After removing zinc powder by filtration from the obtained reaction solution, acetonitrile was removed using an evaporator, and then the viscous elastomer precipitated was dissolved in HCFC-141b. This HCFC-141b solution was washed with water four times, then washed twice with a saturated aqueous sodium thiosulfate solution, and dried using anhydrous magnesium sulfate. After removing magnesium sulfate from the HCFC-141b solution by filtration, HCFC-141b was removed using an evaporator and drying under reduced pressure at 120 ° C. to obtain a viscous fluorine-containing elastomer. In the ¹ H-NMR analysis of the elastomer in a heavy acetone solvent, the peak derived from the terminal structure —CF ₂ CH ₂ I observed in Reference Example 1 was not observed, but —CF═CH of terminal unsaturated bond A complex peak around 5.1 to 5.4 ppm derived from ₂ was observed. In IR measurement, since sharp absorption at 1693 cm ⁻¹ based on C═C stretching of the terminal unsaturated structure was observed, it is considered that the structure of terminal iodine of the fluorine-containing elastomer was converted to a terminal unsaturated structure. Moreover, since the ratio of the intensity of the complex peak derived from —CF═CH ₂ and the intensity of the peak derived from the main chain —CH ₂ — of the fluorine-containing elastomer was 1:34, the structure of the iodine terminal was all terminal. It is thought that it was converted to an unsaturated structure.

Example 2
In a 300 ml three-necked flask, 2 g of the fluorine-containing elastomer having an unsaturated structure at the terminal obtained in Example 1 was dissolved in 100 ml of acetone and cooled in an ice bath. Then, 0.316 g of potassium permanganate ( 3.8 times the molar amount of the unsaturated portion content of the fluorine-containing elastomer) was added. Under stirring, the ice bath was removed and stirring was continued at room temperature for 5 hours. The mixture was cooled again in an ice bath, 100 ml of methanol was added dropwise, the ice bath was removed, and the mixture was stirred at room temperature for 1 hour.

When the obtained reaction solution was concentrated with an evaporator, a viscous elastomer was precipitated. Therefore, after redissolving in HCFC-141b, the insoluble matter was filtered. This HCFC-141b solution was washed with dilute hydrochloric acid using a separatory funnel, and then washed with water three times. The HCFC-141b solution was dried over anhydrous MgSO ₄ , and MgSO ₄ was removed by filtration. Then, HCFC-141b was removed by drying under reduced pressure at 120 ° C. with an evaporator to obtain a viscous fluorine-containing elastomer.

In this fluorine-containing elastomer, a complicated peak derived from terminal unsaturated bonds observed in the fluorine-containing elastomer obtained in Example 1 was not observed by ¹ H-NMR analysis using heavy acetone. Further, in IR measurement, a large absorption of 1773 cm ⁻¹ derived from the C═O stretching of the terminal carboxylic acid structure was observed, but the sharp absorption of 1693 cm ⁻¹ observed in Example 1 was not observed. The terminal unsaturated structure is considered to have changed to carboxylic acid.

Example 3
18.13 g of the fluorine-containing elastomer obtained in Reference Example 1 was dissolved in 150 g of methanol in a four-necked flask equipped with a reflux condenser, and 1.71 g of zinc powder (manufactured by Primary Kishida Chemical Co., Ltd.) After adding 5.6 times the molar amount of the fluorine elastomer —CF ₂ CH ₂ I content), the mixture was heated with stirring for 18 hours to reflux methanol.

From the obtained reaction solution, zinc powder was removed by filtration, and then methanol was removed using an evaporator, and then the viscous elastomer that precipitated was dissolved in HCFC-141b. This HCFC-141b solution was washed with water four times, then washed twice with a saturated aqueous sodium thiosulfate solution, and dried using anhydrous magnesium sulfate. After removing magnesium sulfate from the HCFC-141b solution by filtration, HCFC-141b was removed using an evaporator and drying under reduced pressure at 120 ° C. to obtain a viscous fluorine-containing elastomer. In the ¹ H-NMR analysis of the elastomer in a heavy acetone solvent, the peak derived from the terminal structure —CF ₂ CH ₂ I observed in Reference Example 1 was not observed, but —CF═CH of terminal unsaturated bond A complex peak around 5.1 to 5.4 ppm derived from ₂ was observed. However, a complex peak around 1.6 to 1.9 ppm based on the structure of —CF ₂ CH ₃ in which iodine of —CF ₂ CH ₂ I was replaced with hydrogen was also observed. The ratio between the intensity of the complex peak derived from —CF═CH ₂ and the intensity of the peak derived from the main chain —CH ₂ — of the fluorine-containing elastomer was 0.75: 34. In IR measurement, a sharp absorption of 1693 cm ⁻¹ based on C═C stretching of the terminal unsaturated structure was observed. From the above analysis, it is considered that 75% of the iodine terminal structure was converted to a terminal unsaturated structure.

Example 4
10.41 g of the fluorine-containing elastomer obtained in Reference Example 1 was dissolved in 100 g of anhydrous tetrahydrofuran under water-free conditions in a four-necked flask equipped with a reflux condenser, and further zinc powder (manufactured by Kishida Chemical Co., Ltd.) ) 0.981 g (5.6 molar amount relative to the —CF ₂ CH ₂ I content of the fluorine-containing elastomer) was added, followed by heating for 18 hours with stirring to reflux tetrahydrofuran.

After removing zinc powder by filtration from the obtained reaction solution, tetrahydrofuran was removed using an evaporator, and the viscous elastomer that precipitated was dissolved in HCFC-141b. This HCFC-141b solution was washed with water four times, then washed twice with a saturated aqueous sodium thiosulfate solution, and dried using anhydrous magnesium sulfate. After removing magnesium sulfate from the HCFC-141b solution by filtration, HCFC-141b was removed using an evaporator and drying under reduced pressure at 120 ° C. to obtain a viscous fluorine-containing elastomer. In the ¹ H-NMR analysis of the elastomer in a heavy acetone solvent, the peak derived from the terminal structure —CF ₂ CH ₂ I observed in Reference Example 1 was not observed, but —CF═CH of terminal unsaturated bond A complex peak around 5.1 to 5.4 ppm derived from ₂ was observed. However, a complex peak around 1.6 to 1.9 ppm based on the structure of —CF ₂ CH ₃ in which iodine of —CF ₂ CH ₂ I was replaced with hydrogen was also observed. The ratio of the intensity of the complex peak derived from —CF═CH ₂ and the intensity of the peak derived from the main chain —CH ₂ — of the fluorine-containing elastomer was 0.74: 34. In IR measurement, a sharp absorption of 1693 cm ⁻¹ based on C═C stretching of the terminal unsaturated structure was observed. From the above analysis, it is considered that 74% of the iodine terminal structure was converted to a terminal unsaturated structure.

  In the production method of the present invention, a group having an unsaturated bond can be introduced via a carbon-carbon bond at the main chain end and / or the side chain end of the fluorine-containing elastomer. By crosslinking the composition, a molded product having excellent heat resistance and small compression set (CS) can be obtained. Moreover, the curable composition containing this fluorine-containing elastomer is excellent in workability, and can form a molded article having a complicated shape. Moreover, since this fluorine-containing elastomer has a highly reactive unsaturated group, it is also possible to convert the unsaturated group and introduce a different functional group.

Claims (7)

At the main chain end and / or side chain end, the general formula (1):

Or general formula (2):

Wherein X ¹ , X ² and X ³ are the same or different and are a hydrogen atom, a fluorine atom, —CH ₃ or —CF ₃ , Y ¹ is an iodine atom, a bromine atom or a chlorine atom, and Z is fluorine An atom, an iodine atom, a bromine atom, a chlorine atom, —OR ¹ , or —SR ¹ (R ¹ is an alkyl group having 1 to 5 carbon atoms, an acyl group having 1 to 5 carbon atoms, a benzoyl group, an aryl group, a tosyl group, A trifluoromethanesulfonyl group, and part or all of the hydrogen atoms of these groups may be substituted with fluorine atoms))
In the fluorine-containing elastomer having a site represented by
An alkali metal, an alkaline earth metal, and / or a transition metal,
The site represented by the general formula (1) or (2) is represented by the general formula (3):

(Wherein X ¹ , X ² and X ³ are the same as above)
The manufacturing method of a fluorine-containing elastomer including the process converted into the site | part shown by. Furthermore, an oxidant is allowed to act so that the general formula (3):

(Wherein X ¹ , X ² and X ³ are the same as above)
The method for producing a fluorine-containing elastomer according to claim 1, comprising a step of converting the site represented by -COOH into -COOH. General formula (4):
B _a- (M)-(A) -C _b (4)
(In the formula, M is a structural unit derived from vinylidene fluoride and / or tetrafluoroethylene, A is a structural unit derived from an ethylenic monomer copolymerizable with M, and B and C are the same or different. General formula (5):

Wherein X ¹ , X ² and X ³ are the same or different and are a hydrogen atom, a fluorine atom, —CH ₃ or —CF ₃ , and R ² is an alkylene which may contain an ether bond having 1 to 5 carbon atoms. A part of or all of the hydrogen atoms may be substituted with fluorine atoms, and n is an integer of 0 or more)
Wherein a and b are each 0 or 1, and a + b ≠ 0. )
A fluorine-containing elastomer represented by   The fluorine-containing elastomer according to claim 3, wherein the fluorine-containing elastomer is a vinylidene fluoride-based fluororubber.   The fluorine-containing elastomer according to claim 3 or 4, wherein the number average molecular weight is 500 to 500,000.   A curable composition comprising the fluorine-containing elastomer according to any one of claims 3 to 5.   A molded article obtained by crosslinking the curable composition according to claim 6.