Olefin-containing vulcanization point monomer, preparation method therefor, and fluoropolymer elastomer

Abstract

The present invention provides an olefin-containing vulcanization point monomer as represented by formula (CXY＝CX-R2)n-R1-(Rf-M)m, and further provides a preparation method for the olefin-containing vulcanization point monomer. Furthermore, the present application further provides a preparation method for a fluoropolymer elastomer and a peroxide-cured fluoropolymer elastomer. The olefin-containing vulcanization point monomer provided in the present application contains a plurality of bromine / iodine atoms, and can provide a plurality of vulcanization points for the fluoropolymer elastomer, such that a peroxide-cured fluoropolymer elastomer has the advantages of a high cross-linking density, low permanent compression deformation and excellent processing performance.

Description

Olefin-containing curing site monomer, preparation method thereof and fluoropolymer elastomer

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on February 26, 2024, with application number 202410211762.X and invention name “Olefin-containing vulcanization site monomer, preparation method thereof and fluoropolymer elastomer”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present invention relates to the technical field of fluoropolymer elastomers, in particular to an olefin-containing vulcanization point monomer, a preparation method thereof and a fluoropolymer elastomer. Background Art

[0003] At present, there are many types of fluoropolymer elastomers sold on the market, including bisphenol-cured fluoropolymer elastomers, peroxide-cured fluoropolymer elastomers and polyamine-cured fluoropolymer elastomers. Among them, peroxide-cured fluoropolymer elastomers have a higher fluorine content. Compared with other curing systems, they have higher resistance to water vapor, chemical media and low fuel permeation.

[0004] Conventional peroxide-cured fluoropolymer elastomers generally use iodine or bromine atoms as vulcanization site monomers, usually with a linear structure, and each vulcanization site monomer has only one iodine atom. When peroxide-cured, they cannot form a tighter three-dimensional network structure. The resulting fluoropolymer elastomer products have low crosslinking density and high permanent compression deformation, and also affect the product's processability, such as demolding. Therefore, their application in high-end sealing fields such as automobiles, semiconductors, electronic terminals, and new energy is limited.

[0005] In order to solve the problems of low crosslinking, high compression set, and easy adhesion during demolding of the above-mentioned fluoropolymer elastomers, and to produce fluoropolymer elastomer sealing rings and pipes with better performance, the present invention proposes a highly crosslinkable polyiodinated and / or polybrominated olefin-containing vulcanization site monomer structure. Summary of the Invention

[0006] The technical problem solved by the present invention is to provide a vulcanization site monomer containing olefins. The vulcanization site monomer containing olefins provided in the present application is applied to fluoropolymer elastomers to obtain peroxide-cured fluoropolymer elastomers with excellent processing performance and lower permanent compression set.

[0007] In view of this, the present application provides an olefin-containing sulfurization site monomer as shown in formula (I), (CXY=CX-R2) n -R1-(R f -M) m(Ⅰ);

[0008] wherein X is selected from H, F, -CH2- or a C1-C10 alkyl group containing a substituent; Y is selected from H, F, CH- or a C1-C10 alkyl group containing a substituent; R2 is selected from a C1-C10 alkylene group containing a substituent or not; R1 is selected from a linking group; n is 1-2, m is 2-6; M is selected from Br or I;

[0009] R f Having the structure shown in formula (II); R2-CXY-CX-R4- (II);

[0010] wherein R4 is selected from -(CF2) a -and-(CF2) b -(CH2) c -One or more of;

[0011] Among them, a is 1 to 8, b is 1 to 8, and c is 0 to 4.

[0012] Preferably, the R1 is C, N, P, B,

[0013] Preferably, the R2 is selected from -(CH2) d -、-(CH2-O) d -、-(CH2) d -O-, -(CH2) d -O-CO-, -(CF2) d -、-(CF2-O) d -、-(CF2) d -O- and -(CF2) d One or more of -O-CO-; wherein d is 1 to 8.

[0014] The present application also provides a method for preparing the olefin-containing sulfurization site monomer, comprising the following steps:

[0015] A) mixing a raw material 1 as described in formula (III) and a raw material 2 as described in formula (IV) in a solvent to obtain a mixed raw material;

[0016] B) reacting the mixed raw materials under the action of copper acetate and cesium carbonate to obtain a sulfide monomer; (CXY=CX-R2) n -R1-(R2-CX=CXY) m (Ⅲ); M-R4-M (Ⅳ);

[0017] wherein X is selected from H, F, -CH2- or a C1-C10 alkyl group containing a substituent; Y is selected from H, F, CH- or a C1-C10 alkyl group containing a substituent; R2 is selected from a C1-C10 alkylene group containing a substituent or not; R1 is selected from a linking group; n is 1-2, m is 2-6; M is selected from Br or I;

[0018] R4 is selected from -(CF2) a -and-(CF2) b -(CH2) c -One or more of;

[0019] a is 1 to 8, b is 1 to 8, and c is 0 to 4.

[0020] Preferably, the molar ratio of the raw material one to the raw material two is 1:2.

[0021] Preferably, the reaction is carried out in a protective atmosphere at a temperature of 80 to 120° C. for 10 to 15 hours.

[0022] The present application also provides a fluoropolymer elastomer, comprising a fluorine-containing monomer and an olefin-containing vulcanization site monomer, characterized in that the olefin-containing vulcanization site monomer is the vulcanization site monomer described or the vulcanization site monomer prepared by the preparation method described.

[0023] Preferably, the vulcanization site monomer is 0.02-2 wt% of the total of the fluorine-containing monomer and the olefin-containing vulcanization site monomer, and the total of the fluorine-containing monomer and the olefin-containing vulcanization site monomer is 98-99.5 wt% of the fluoropolymer elastomer.

[0024] Preferably, the fluoropolymer elastomer further includes an emulsifier, an initiator, and a chain transfer agent, wherein the emulsifier is selected from ammonium perfluorooctanoate, the initiator is selected from one or more of persulfate, persulfate-bisulfite and diisopropyl peroxydicarbonate, and the chain transfer agent is selected from one or more of diiododifluoromethane, diiodoperfluoropropane and diiodoperfluorobutane.

[0025] Preferably, the emulsifier is 0.05-1 wt% of the fluoropolymer elastomer, the initiator is 0.01-0.1 wt% of the fluoropolymer elastomer, and the chain transfer agent is 0.1-1 wt% of the fluoropolymer elastomer.

[0026] Preferably, the method for preparing the fluoropolymer elastomer comprises the following steps:

[0027] A) replacing the gas in the polymerization reaction vessel with nitrogen, adding water and an emulsifier, replacing the gas in the polymerization reaction vessel with nitrogen again, and heating the polymerization reaction vessel to 80-120° C.;

[0028] B) adding a fluorine-containing monomer to the polymerization reaction vessel obtained in step A), then adding an olefin-containing vulcanization point monomer, adjusting the temperature of the polymerization reaction solution to 80-120° C., and finally adding an initiator to start a polymerization reaction; supplementing the initiator, fluorine-containing monomer and chain transfer agent during the polymerization reaction to obtain a fluoropolymer elastomer.

[0029] Preferably, in step B), after the fluorine-containing monomer is added, the pressure of the polymerization reaction vessel is 1.2-1.3 MPa.

[0030] Preferably, the polymerization reaction pressure is 1.2-1.3 MPa and the temperature is 80-120°C.

[0031] The present application also provides a method for preparing a peroxide-cured fluoropolymer elastomer, comprising:

[0032] vulcanizing the fluoropolymer elastomer and the crosslinking agent under the action of a peroxide vulcanizing agent to obtain a peroxide-cured fluoropolymer elastomer;

[0033] The fluoropolymer elastomer is the fluoropolymer elastomer described above.

[0034] Preferably, the vulcanizing agent is di-2,5-dimethylbenzene; the crosslinking agent is TAIC crosslinking agent; the vulcanization includes primary vulcanization and secondary vulcanization, the temperature of the primary vulcanization is 150-170°C, the time is 10-20 minutes, and the temperature of the secondary vulcanization is 170-200°C, the time is 3-5 hours.

[0035] The present application provides a vulcanization point monomer containing olefins, which has a structure with at least two iodine atoms or bromine atoms. When applied to a fluoropolymer elastomer, the fluoropolymer elastomer structure has more crosslinking points, and is more likely to form a three-dimensional network structure during the later peroxide curing process, thereby obtaining a peroxide-cured fluoropolymer elastomer with a high crosslinking density and lower permanent compression set, and the fluoropolymer elastomer has good processing performance. DETAILED DESCRIPTION

[0036] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0037] To address the problems of low crosslinking, high compression set, and easy sticking during demolding in existing fluoropolymer elastomers, this application provides an olefin-containing curing site monomer. This monomer, through a structure containing at least two iodine or bromine atoms, increases the crosslinking density of the fluoropolymer elastomer and reduces the permanent compression set of the fluoropolymer elastomer. Specifically, this application provides an olefin-containing curing site monomer as shown in formula (I): (CXY=CX-R2) n -R1-(R f -M) m (Ⅰ);

[0038] wherein X is selected from H, F, -CH2- or a C1-C10 alkyl group containing a substituent; Y is selected from H, F, CH- or a C1-C10 alkyl group containing a substituent; R2 is selected from a C1-C10 alkylene group containing a substituent or not; R1 is selected from a linking group; n is 1-2, m is 2-6; M is selected from Br or I;

[0039] R f Having the structure shown in formula (II); R2-CXY-CX-R4- (II);

[0040] wherein R4 is selected from -(CF2) a -and-(CF2) b -(CH2) c -One or more of;

[0041] Among them, a is 1 to 8, b is 1 to 8, and c is 0 to 4.

[0042] In the olefin-containing sulfur-site monomer provided herein, X can be specifically selected from H, -CH2-, -CH(CH3)- or -CH(CH3)-CH2-, and Y can be selected from H, F, CH-, -C(CH3) or -CH(CH3)-CH or -CF. R2 can be specifically selected from -(CH2) d -、-(CH2-O) d -、-(CH2) d -O-, -(CH2) d -O-CO-, -(CF2) d -、-(CF2-O) d -、-(CF2) d -O- and -(CF2) d -O-CO-; wherein, d is 1 to 8, specifically, d is 1, 2, 3, 4, 5, 6, 7 or 8; more specifically, R2 is selected from -CH2-.

[0043] R1 is a connecting group, which can be selected from C, N, P, B, m is 2 to 6, more specifically, m is 2, 3, 4, 5 or 6.

[0044] R f Having the structure shown in formula (II); R2-CXY-CX-R4- (II);

[0045] wherein R4 is selected from -(CF2) a -and-(CF2) b -(CH2) c -One or more of;

[0046] a is 1 to 8, b is 1 to 8, and c is 0 to 4.

[0047] More specifically, a is 1, 2, 3, 4, 5, 6, 7 or 8, b is 1, 2, 3, 4, 5, 6, 7 or 8, and c is 0, 1, 2, 3 or 4.

[0048] Furthermore, the present application also provides a method for preparing the above-mentioned olefin-containing sulfurization site monomer, comprising the following steps:

[0049] A) mixing a raw material 1 as described in formula (III) and a raw material 2 as described in formula (IV) in a solvent to obtain a mixed raw material;

[0050] B) reacting the mixed raw materials under the action of copper acetate and cesium carbonate to obtain a sulfide monomer; (CXY=CX-R2) n -R1-(R2-CX=CXY) m (Ⅲ); M-R4-M (Ⅳ);

[0051] wherein X is selected from H, F, -CH2- or a C1-C10 alkyl group containing a substituent; Y is selected from H, F, CH- or a C1-C10 alkyl group containing a substituent; R2 is selected from a C1-C10 alkylene group containing a substituent or not; R1 is selected from a linking group; n is 1-2, m is 2-6; M is selected from Br or I;

[0052] R4 is selected from -(CF2) a -and-(CF2) b -(CH2) c -One or more of;

[0053] a is 1 to 8, b is 1 to 8, and c is 0 to 4.

[0054] In the preparation process of the olefin-containing sulfur-site monomer, the present application first converts (CXY=CX-R2) n -R1-(R2-CX=CXY)m and M-R4-M in a solvent, mixed and stirred to obtain a mixed raw material; the solvent is a solvent well known to those skilled in the art. In a specific embodiment, the solvent is specifically selected from N, N-dimethylformamide, and the (CXY=CX-R2) n -R1-(R2-CX=CXY) m The molar ratio of the raw material to the M-R4-M is 1:2; and the mixing and stirring time is 20 to 40 minutes. In a specific embodiment, the raw material 1 can be selected from tetraallylmethane, triallylamine, triallyl isocyanurate, 1,3,5-triallyloxybenzene or 2,4,6-tris(diallylamino)-1,3,5-triazine, and the raw material 2 can be selected from 1,3-diiodohexafluoropropane, 1,4-diiodoperfluorobutane, 1,2-diiodoperfluoroethane, 1,2-diiodoethane or 1,4-dibromoperfluorobutane.

[0055] According to the present invention, the mixed raw materials are then reacted in a nitrogen atmosphere under the action of copper acetate and cesium carbonate to obtain a vulcanization site monomer; the reaction temperature is 80-120° C. and the reaction time is 10-15 hours; specifically, the reaction temperature is 90-100° C. and the reaction time is 11-12 hours.

[0056] The present application also provides a fluoropolymer elastomer, which includes a fluorine-containing monomer and an olefin-containing vulcanization site monomer, wherein the olefin-containing vulcanization site monomer is specifically the olefin-containing vulcanization site monomer described in the above scheme.

[0057] In the fluoropolymer elastomer provided herein, the fluorine-containing monomer may be selected from one or more of vinylidene fluoride, tetrafluoroethylene, and hexafluoropropylene. The vulcanization site monomer may be 0.02-2 wt % of the total of the fluorine-containing monomer and the olefin-containing vulcanization site monomer, specifically 0.3-1.5 wt % of the total of the fluorine-containing monomer and the olefin-containing vulcanization site monomer. The total of the fluorine-containing monomer and the olefin-containing vulcanization site monomer may be 98-99.5 wt % of the fluoropolymer elastomer, specifically 98.5-99 wt % of the fluorine-containing monomer and the olefin-containing vulcanization site monomer.

[0058] The raw materials of the fluoropolymer elastomer also include an emulsifier, an initiator, and a chain transfer agent. The emulsifier is selected from ammonium perfluorooctanoate, the initiator is selected from one or more of persulfates, persulfate-bisulfites, and diisopropyl peroxydicarbonate, and the chain transfer agent is selected from one or more of diiododifluoromethane, diiodoperfluoropropane, and diiodoperfluorobutane. More specifically, the initiator is selected from ammonium persulfate, and the chain transfer agent is diiodoperfluorobutane. The initiator is present in an amount of 0.01 to 0.1 wt% of the fluoropolymer elastomer, specifically 0.03 to 0.08 wt% of the fluoropolymer elastomer. The emulsifier is present in an amount of 0.05 to 1 wt% of the fluoropolymer elastomer, specifically 0.1 to 0.8 wt% of the fluoropolymer elastomer. The chain transfer agent is present in an amount of 0.1 to 1 wt% of the fluoropolymer elastomer, specifically 0.3 to 0.7 wt% of the fluoropolymer elastomer. In the present application, the total mass of the fluorine-containing monomer, the olefin-containing cure site monomer, the emulsifier, the initiator and the chain transfer agent is expressed based on the fluoropolymer elastomer.

[0059] The present application further provides a method for preparing the fluoropolymer elastomer, comprising the following steps:

[0060] A) replacing the gas in the polymerization reaction vessel with nitrogen, adding water and an emulsifier, replacing the gas in the polymerization reaction vessel with nitrogen again, and heating the polymerization reaction vessel to 80-120° C.;

[0061] B) adding a fluorine-containing monomer to the polymerization reaction vessel obtained in step A), then adding an olefin-containing vulcanization point monomer, adjusting the temperature of the polymerization reaction solution to 80-120° C., and finally adding an initiator to start a polymerization reaction; supplementing the initiator, fluorine-containing monomer and chain transfer agent during the polymerization reaction to obtain a fluoropolymer elastomer.

[0062] In the above process, the pressure after adding the fluorine-containing monomer is 1.2-1.3 MPa. Similarly, the pressure of the polymerization reaction is 1.2-1.3 MPa and the temperature is 83-120°C.

[0063] The present application also provides a method for preparing a peroxide-cured fluoropolymer elastomer, comprising the following steps:

[0064] vulcanizing the fluoropolymer elastomer and the crosslinking agent under the action of a peroxide vulcanizing agent to obtain a peroxide-cured fluoropolymer elastomer;

[0065] The fluoropolymer elastomer is the fluoropolymer elastomer described in the above embodiment.

[0066] In the preparation process of peroxide-cured fluoropolymer elastomer, the crosslinking agent is TAIC crosslinking agent, the vulcanizing agent is di-2,5 vulcanizing agent, the vulcanization includes primary vulcanization and secondary vulcanization, the temperature of the primary vulcanization is 150-170°C, the time is 10-20 minutes, and the temperature of the secondary vulcanization is 170-200°C, and the time is 3-5 hours.

[0067] In the above process, based on 100 parts by weight of the fluoropolymer elastomer, the content of the crosslinking agent is 3 to 5 parts by weight, and the content of the vulcanizing agent is 1 to 3 parts by weight.

[0068] The following specifically describes the formation process of a peroxide-cured fluoropolymer elastomer prepared from a polybrominated or polyiodinated olefin-containing cure site monomer and the formation process of a peroxide-cured fluoropolymer elastomer prepared from a monobrominated or monoiodinated olefin-containing cure site monomer:

[0069] Taking the polyiodinated olefin prepared in Example 3 as an example, the structure of the fluoropolymer elastomer (olefin polymerization reaction under the initiator (ammonium persulfate)) composed thereof is shown below:

[0070] It undergoes cross-linking and curing under the action of peroxide vulcanizing agent and cross-linking agent. The process and structure of the obtained peroxide-cured fluoropolymer elastomer are as follows:

[0071] The structure of the fluoropolymer elastomer composed of monoiodinated olefin (4-iodo-1-butene) is as follows:

[0072] It undergoes cross-linking and curing under the action of peroxide vulcanizer and cross-linking agent:

[0073] represent

[0074] According to the formation process of the above-mentioned peroxide-curable fluoropolymer elastomer, it can be seen that the poly-iodinated or poly-brominated olefin-containing vulcanization site monomer is conducive to the formation of a highly cross-linked fluoropolymer elastomer, thereby ultimately improving its sealing performance, processability and low compression set.

[0075] In order to further understand the present invention, the olefin-containing sulfide monomer, its preparation method and application provided by the present invention are described in detail below with reference to the examples. The protection scope of the present invention is not limited by the following examples.

[0076] Example 1

[0077] The polyolefin compounds involved in the polyiodinated olefin synthesis method are conventional chemical reagents, and the source is not limited, as long as the purity is greater than 98%. The synthesis method of the corresponding polyiodinated olefin compound is as follows:

[0078] 1) Synthesis of polyiodinated olefin 1

[0079] Under nitrogen protection, tetraallylmethane (17.7 g, 0.1 mol), copper acetate [Cu(OAc)2] (1.27 g, 0.007 mmol), cesium carbonate [Cs2CO3] (96.7 g, 0.3 mol), and DMF (500 mL) were added sequentially to a Shrek reaction flask. After stirring and dissolving, 1,3-diiodohexafluoropropane (120 g, 0.3 mol) was added to the flask. After the addition of the raw materials was complete, the mixture was heated to 100°C under nitrogen protection and stirred for 12 hours. The reaction was stopped after the LC analysis showed no change in the raw materials or intermediates. Ethyl acetate was then added to the reaction solution, which was washed sequentially with water and saturated brine, dried, and concentrated to obtain crude polyiodinated olefin 1. The crude product was then distilled under reduced pressure to obtain the sulfide monomer, the structural formula of which is shown below:

[0080] 1 H NMR (400MHz, CDCl3, δ): 5.77 (m, 1H), 5.14-5.27 (m, 2H), 4.43 (d, 2H), 3.75 (t, 6H), 2.66 (m, 6H), 1.74 (m, 6H).

[0081] 2) Synthesis of polyiodinated olefins 2

[0082] Under nitrogen protection, triallylamine (13.7 g, 0.1 mol), copper acetate [Cu(OAc)2] (1.27 g, 0.007 mmol), cesium carbonate [Cs2CO3] (64.5 g, 0.2 mol), and DMF (500 mL) were added sequentially to a Shrek reaction flask. After stirring to dissolve, 1,3-diiodohexafluoropropane (80.6 g, 0.2 mol) was added to the reaction flask. After the raw materials were completely added, the reaction was heated to 100°C and stirred for 12 hours under nitrogen protection. The reaction was stopped after LC control showed no change in the raw materials and intermediates. Ethyl acetate was then added to the reaction solution, which was washed sequentially with water and saturated brine, dried, and concentrated to obtain crude polyiodinated olefin 2. The crude product was then distilled under reduced pressure to obtain the sulfide monomer, the structural formula of which is shown below:

[0083] 1H NMR (400MHz, CDCl3, δ): 5.82 (m, 1H), 5.1-5.21 (m, 2H), 4.39 (d, 2H), 3.81 (t, 4H), 2.72 (m, 4H), 1.71 (m, 4H).

[0084] 3) Synthesis of polyiodinated olefins 3

[0085] a. A mixture of triallyl isocyanurate (30 g, 0.12 mol), Grubbs second-generation catalyst (Grubbs second-generation, 20 mol%, 0.024 mol), ethyl vinyl ether (20 mol%, 0.024 mol) and o-dichlorobenzene (0.6 mL) was placed in a pressure-resistant reactor; then, the gas phase in the reactor was replaced with tetrafluoroethylene (1.0 atm, 2.7 mL, 0.12 mol); the reactor was heated at 180° C. for 1 hour. After the reaction was completed, the reaction mixture was cooled and concentrated to obtain the intermediate shown in the following formula, which was directly subjected to the next reaction;

[0086] b. Under N2 protection, the intermediate of the previous step (28.5 g, 0.1 mol), copper acetate [Cu(OAc)2] (1.27 g, 0.007 mmol), cesium carbonate [Cs2CO3] (64.5 g, 0.2 mol) and DMF (500 mL) were added to a Shrek reaction flask in sequence. After stirring and dissolving, 1,3-diiodohexafluoropropane (80.6 g, 0.2 mol) was added to the reaction flask. After the raw materials were added completely, the mixture was heated to 100°C and stirred for 12 h under N2 protection. The reaction was stopped after the reaction raw materials and intermediates showed no change by LC. Ethyl acetate was then added to the reaction solution, which was washed with water and saturated brine in sequence, dried, and concentrated to obtain a crude product of polyiodinated olefin 3. The crude product was then stirred and slurried with petroleum ether, filtered, washed with petroleum ether, and dried to obtain a sulfide monomer with the structural formula shown below:

[0087] 1 H NMR (400MHz, DMSO, δ): 5.78 (m, 1H), 4.43 (d, 2H), 3.87 (t, 4H), 2.73 (m, 4H), 1.76 (m, 4H).

[0088] 4) Synthesis of polyiodinated olefins 4

[0089] Under N2 protection, triallyl isocyanurate (24.9 g, 0.1 mol), copper acetate [Cu(OAc)2] (1.27 g, 0.007 mmol), cesium carbonate [Cs2CO3] (64.5 g, 0.2 mol) and DMF (500 mL) were added to a Shrek reaction flask in sequence. After stirring and dissolving, 1,4-diiodoperfluorobutane (90.7 g, 0.2 mol) was added to the reaction flask. After the raw materials were completely added, the mixture was heated to 100°C and stirred for 12 h under N2 protection. The reaction was stopped after LC control showed no change in the raw materials and intermediates. Ethyl acetate was then added to the reaction solution, which was washed with water and saturated brine in sequence, dried, and concentrated to obtain a crude product of polyiodinated olefin 4. The crude product was then stirred and slurried with petroleum ether, filtered, washed with petroleum ether, and dried to obtain a sulfide monomer with the structural formula shown below:

[0090] 1 H NMR (400MHz, DMSO, δ): 5.8 (m, 1H), 5.2-5.25 (m, 2H), 4.42 (d, 2H), 3.84 (t, 4H), 2.76 (m, 4H), 1.78 (m, 4H).

[0091] 5) Synthesis of polyiodinated olefin 5

[0092] Under N2 protection, 1,3,5-triallyloxybenzene (24.6 g, 0.1 mol), copper acetate [Cu(OAc)2] (1.27 g, 0.007 mmol), cesium carbonate [Cs2CO3] (64.5 g, 0.2 mol) and DMF (500 mL) were added to a Shrek reaction flask in sequence. After stirring and dissolving, 1,4-diiodoperfluorobutane (90.7 g, 0.2 mol) was added to the reaction flask. After the raw materials were added completely, the mixture was heated to 100°C and stirred for 12 h under N2 protection. The reaction was stopped after LC control showed no change in the raw materials and intermediates. Ethyl acetate was then added to the reaction solution, which was washed with water and saturated brine in sequence, dried, and concentrated to obtain a crude product of polyiodinated olefin 5. The crude product was then stirred and slurried with petroleum ether, filtered, washed with petroleum ether, and dried to obtain a sulfide monomer with the structural formula shown below:

[0093] 1 H NMR (400MHz, CDCl3, δ): 6.13 (s, 3H), 5.97 (m, 1H), 5.2-5.25 (m, 2H), 4.5 (d, 2H), 4.2 (t, 4H), 2.81 (m, 4H), 1.68 (m, 4H).

[0094] 6) Synthesis of polyiodinated olefins 6

[0095] Under N2 protection, 2,4,6-tris(diallylamino)-1,3,5-triazine (36.6 g, 0.1 mol), copper acetate [Cu(OAc)2] (1.27 g, 0.007 mmol), cesium carbonate [Cs2CO3] (129 g, 0.4 mol) and DMF (1000 mL) were added to a Shrek reaction flask in sequence. After stirring and dissolving, 1,2-diiodoperfluoroethane (141.5 g, 0.4 mol) was added to the reaction flask. After the raw materials were added completely, the mixture was heated to 100°C and stirred for 12 h under N2 protection. The reaction was stopped after LC control showed no change in the raw materials and intermediates. Ethyl acetate was then added to the reaction solution, which was washed with water and saturated brine in sequence, dried, and concentrated to obtain a crude product of polyiodinated olefin 6. The crude product was then stirred with petroleum ether, filtered, washed with petroleum ether, and dried to obtain a sulfide monomer with the structural formula shown below:

[0096] 1 H NMR (400MHz, DMSO, δ): 5.9 (m, 2H), 5.3-5.35 (m, 4H), 4.47 (d, 4H), 3.9 (t, 8H), 2.9 (m, 8H), 1.72 (m, 8H).

[0097] 7) Synthesis of polyiodinated olefins 7

[0098] Under N2 protection, triallyl isocyanurate (24.9 g, 0.1 mol), copper acetate [Cu(OAc)2] (1.27 g, 0.007 mmol), cesium carbonate [Cs2CO3] (64.5 g, 0.2 mol) and DMF (500 mL) were added to a Shrek reaction flask in sequence. After stirring and dissolving, 1,2-diiodoethane (56.4 g, 0.2 mol) was added to the reaction flask. After the raw materials were completely added, the mixture was heated to 100°C and stirred for 12 h under N2 protection. The reaction was stopped after LC control showed no change in the raw materials and intermediates. Ethyl acetate was then added to the reaction solution, which was washed with water and saturated brine in sequence, dried, and concentrated to obtain a crude product of polyiodinated olefin 7. The crude product was then stirred and slurried with petroleum ether, filtered, washed with petroleum ether, and dried to obtain a sulfide monomer with the structural formula shown below:

[0099] 1 H NMR (400MHz, DMSO, δ): 5.69 (m, 1H), 5.1-5.2 (m, 2H), 4.45 (d, 2H), 3.9 (t, 4H), 3.2 (m, 4H), 1.4-1.8 (m, 12H).

[0100] 8) Synthesis of polybrominated olefins 8

[0101] Under nitrogen protection, triallyl isocyanurate (24.9 g, 0.1 mol), copper acetate [Cu(OAc)2] (1.27 g, 0.007 mmol), cesium carbonate [Cs2CO3] (64.5 g, 0.2 mol), and DMF (500 mL) were added sequentially to a Shrek reaction flask. After stirring and dissolving, 1,4-dibromoperfluorobutane (72 g, 0.2 mol) was added to the flask. After the addition of the raw materials was complete, the reaction was heated to 100°C and stirred for 12 hours under nitrogen protection. The reaction was stopped after LC control showed no change in the raw materials and intermediates. Ethyl acetate was then added to the reaction solution, which was washed sequentially with water and saturated brine, dried, and concentrated to obtain crude polyiodinated olefin 8. The crude product was then stirred with petroleum ether, filtered, washed with petroleum ether, and dried to obtain the sulfide monomer, the structural formula of which is shown below:

[0102] 1 H NMR (400MHz, DMSO, δ): 5.86 (m, 1H), 5.2-5.3 (m, 2H), 4.5 (d, 2H), 3.87 (t, 4H), 2.8 (m, 4H), 1.73 (m, 4H).

[0103] Example 2 Synthesis of highly cross-linked peroxide-curable fluoropolymer elastomer:

[0104] Step ①: Repeatedly use nitrogen N2 to replace the gas in the polymerization reaction vessel to fully expel the oxygen therein; inject a certain amount of deionized water and emulsifier solution into the polymerization reaction vessel from which oxygen has been removed;

[0105] Step 2: Replace the oxygen in the polymerization reaction vessel with N2 again and heat the temperature in the polymerization reaction vessel to 80°C;

[0106] Step ③: injecting a certain proportion of fluorine-containing mixed monomers such as vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene, and perfluoropolyether olefin into the polymerization reaction vessel obtained in 2) until the pressure in the polymerization reaction vessel reaches 1.2 MPa to 1.3 MPa; during the stirring process, adding a certain amount of highly cross-linkable polyiodinated or polybrominated olefin compound sulfurization point monomer, and adjusting the temperature of the polymerization reaction vessel so that the mixture in the polymerization reaction vessel reaches 80° C., and adding an initiator to start the polymerization reaction;

[0107] Step ④: During the polymerization process, the initiator is added multiple times, a certain proportion of the above-mentioned fluorinated mixed monomer is added, and a certain amount of chain transfer agent is added. The pressure of the polymerization reaction vessel during the polymerization process is maintained at 1.2 MPa to 1.3 MPa and the temperature is 80°C;

[0108] After the polymerization is completed, the polymer obtained is subjected to post-treatment processes such as coagulation and drying to obtain a highly cross-linked peroxide-curable fluoropolymer elastomer.

[0109] Preparation of fluoropolymer elastomers The fluoropolymer elastomers were prepared according to the above method. The proportions of the raw materials and the properties of the fluoropolymer elastomers are shown in Table 1.

[0110] Table 1 Fluoropolymer elastomer preparation raw materials and performance data

[0111] Standard formula: fluoropolymer elastomer prepared in Example (100 parts), carbon black (20 parts), TAIC additive (4 parts), and vulcanizing agent dimethyl sulfoxide (1.5 parts);

[0112] Vulcanization conditions: the first stage vulcanization condition is 160℃×10min, the second stage vulcanization condition is 180℃×4h.

[0113] The above embodiments are only intended to help understand the method and core concept of the present invention. It should be noted that, without departing from the principles of the present invention, a number of improvements and modifications may be made to the present invention by those skilled in the art, and such improvements and modifications also fall within the scope of protection of the claims of the present invention.

[0114] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An olefin-containing sulfur-site monomer represented by formula (I), (CXY=CX-R2) n -R1-(R f -M) m (Ⅰ); in, X is selected from H, F, -CH2- or a C1-C10 alkyl group containing a substituent; Y is selected from H, F, CH- or a C1-C10 alkyl group containing a substituent; R2 is selected from a C1-C10 alkylene group containing a substituent or an unsubstituted C1-C10 group; R1 is selected from a linking group; n is 1-2, m is 2-6; M is selected from Br or I; R f Having the structure shown in formula (II); R2-CXY-CX-R4- (Ⅱ); wherein R4 is selected from -(CF2) a -and-(CF2) b -(CH2) c -One or more of; Among them, a is 1 to 8, b is 1 to 8, and c is 0 to 4.

2. The vulcanization site monomer according to claim 1, wherein The R1 is C, N, P, B, 3. The vulcanization site monomer according to claim 1, characterized in that Said R2 is selected from -(CH2) d -、-(CH2-O) d -、-(CH2) d -O-, -(CH2) d -O-CO-, -(CF2) d -、-(CF2-O) d -、-(CF2) d -O- and -(CF2) d One or more of -O-CO-; wherein d is 1 to 8.

4. The method for preparing the olefin-containing sulfide monomer according to claim 1, comprising the steps of: A) mixing a raw material 1 as described in formula (III) and a raw material 2 as described in formula (IV) in a solvent to obtain a mixed raw material; B) reacting the mixed raw materials under the action of cupric acetate and cesium carbonate to obtain a sulfide monomer; (CXY=CX-R2) n -R1-(R2-CX=CXY) m (III) M-R4-M (Ⅳ); wherein X is selected from H, F, -CH2- or a C1-C10 alkyl group containing a substituent; Y is selected from H, F, CH- or a C1-C10 alkyl group containing a substituent; R2 is selected from a C1-C10 alkylene group containing a substituent or not; R1 is selected from a linking group; n is 1-2, m is 2-6; M is selected from Br or I; R4 is selected from -(CF2) a -and-(CF2) b -(CH2) c -One or more of; a is 1 to 8, b is 1 to 8, and c is 0 to 4.

5. The preparation method according to claim 4, characterized in that The molar ratio of the raw material 1 to the raw material 2 is 1:

2.

6. The preparation method according to claim 4, characterized in that The reaction is carried out in a protective atmosphere at a temperature of 80 to 120° C. for 10 to 15 hours.

7. A fluoropolymer elastomer comprising a fluorine-containing monomer and an olefin-containing vulcanization site monomer, characterized in that: The olefin-containing vulcanization site monomer is the vulcanization site monomer according to any one of claims 1 to 3 or the vulcanization site monomer prepared by the preparation method according to any one of claims 4 to 6.

8. The fluoropolymer elastomer according to claim 7, characterized in that The said curing point monomer is 0.02-2 wt% of the total of the said fluorine-containing monomer and the said olefin-containing curing point monomer, and the total of the said fluorine-containing monomer and the said olefin-containing curing point monomer is 98-99.5 wt% of the said fluoropolymer elastomer.

9. The fluoropolymer elastomer according to claim 7, wherein The fluoropolymer elastomer also includes an emulsifier, an initiator, and a chain transfer agent. The emulsifier is selected from ammonium perfluorooctanoate, the initiator is selected from one or more of persulfate, persulfate-bisulfite and diisopropyl peroxydicarbonate, and the chain transfer agent is selected from one or more of diiododifluoromethane, diiodoperfluoropropane and diiodoperfluorobutane.

10. The fluoropolymer elastomer according to claim 7, wherein The emulsifier accounts for 0.05-1 wt% of the fluoropolymer elastomer, the initiator accounts for 0.01-0.1 wt% of the fluoropolymer elastomer, and the chain transfer agent accounts for 0.1-1 wt% of the fluoropolymer elastomer.

11. The fluoropolymer elastomer according to claim 7, wherein The preparation method of the fluoropolymer elastomer comprises the following steps: A) replacing the gas in the polymerization reaction vessel with nitrogen, adding water and an emulsifier, replacing the gas in the polymerization reaction vessel with nitrogen again, and heating the polymerization reaction vessel to 80-120° C.; B) adding a fluorine-containing monomer to the polymerization reaction vessel obtained in step A), then adding an olefin-containing vulcanization point monomer, adjusting the temperature of the polymerization reaction solution to 80-120° C., and finally adding an initiator to start a polymerization reaction; supplementing the initiator, fluorine-containing monomer and chain transfer agent during the polymerization reaction to obtain a fluoropolymer elastomer.

12. The fluoropolymer elastomer according to claim 11, wherein In step B), after the fluorine-containing monomer is added, the pressure of the polymerization reaction vessel is 1.2-1.3 MPa.

13. The fluoropolymer elastomer according to claim 11, wherein The polymerization reaction is carried out under a pressure of 1.2-1.3 MPa and at a temperature of 80-120°C.

14. A method for preparing a peroxide-cured fluoropolymer elastomer, comprising: vulcanizing the fluoropolymer elastomer and the crosslinking agent under the action of a peroxide vulcanizing agent to obtain a peroxide-cured fluoropolymer elastomer; The fluoropolymer elastomer is the fluoropolymer elastomer according to any one of claims 7 to 11.

15. The preparation method according to claim 14, characterized in that The vulcanizing agent is di-2,5-dimethylbenzene; the crosslinking agent is TAIC crosslinking agent; the vulcanization includes primary vulcanization and secondary vulcanization, the temperature of the primary vulcanization is 150-170°C and the time is 10-20 minutes, and the temperature of the secondary vulcanization is 170-200°C and the time is 3-5 hours.

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