Fluoroelastomers

Abstract

Fluoroelastomers comprising in the polymer chain units deriving from fluorovinyl ethers having the formula:

Description

[0001] The present invention relates to fluorovinyl ethers, the process for preparing them and the polymers obtainable therefrom.

[0002] It is well known that perfluoroalkylvinyl ethers are generally used as monomers for the olefin copolymerization, specifically tetrafluoroethylene, vinylidene fluoride, chlorotrifluoroethylene (CTFE), hexafluoropropene. The introduction of small amounts of perfluoroalkylvinyl ethers in plastomeric polymers implies a higher polymer processability and better hot mechanical properties. The introduction of high amounts of perfluorovinyl ethers in crosslinkable fluoropolymers implies elastomeric properties at low temperature of fluorinated rubbers.

[0003] The need was felt, in the field of fluorinated polymer materials, to produce elastoamers having improved properties at low temperatures. Such properties can generally be expressed by the glass transition temperature Tg.

[0004] A lower Tg allows to have elastomeric polymers which can be used at lower temperatures and therefore to have available elastomers with a wider use range. To obtain the combination of the above mentioned properties, fluorovinyl ethers must have a high unitary capability to modify the base backbone properties, as well as high reactivity to be used as comonomers in elastomeric fluoropolymers. It was desirable to have available vinyl ethers obtainable by simple processes having a limited number of steps. Preferably it would be desirable to have available a continuous process for preparing said vinyl ethers.

[0005] To solve the above technical problem, fluorovinyl ethers having different structural properties, have been proposed in the prior art. However from the prior art, hereinafter described, various unsolved problems result evident in the perfluorovinylether synthesis and in the preparation of the corresponding polymers having the combination of the above mentioned properties.

[0006] U.S. Pat. No. 3,132,123 describes the preparation of perfluoroalkylvinyl ethers, of the corresponding homopolymers and copolymers with TFE. Homopolymers are obtained under extreme experimental conditions, by using polymerization pressures from 4,000 to 18,000 atm. The perfluoromethylvinylether (PMVE) homopolymer is an elastomer: the Tg is not reported. The general formula of the described vinyl ethers is the following:

CF2═CFORoF

[0007] wherein RoF is a perfluoroalkyl radical preferably from 1 to 5 carbon atoms. A process for preparing these vinyl ethers is described in U.S. Pat. No. 3,291,843 wherein the starting acylfluoride is salified and pyrolized with carbonates also in the presence of solvents. By this process undesired hydrogenated byproducts are obtained.

[0008] U.S. Pat. No. 3,450,684 relates to vinyl ethers having the formula:

CF2═CFO(CF2CFX0O)n, CF2CF2X0

[0009] wherein X0═F, Cl, CF3, H and n′ can range from 1 to 20. Also homopolymers obtained by UV polymerization are reported. The exemplified copolymers are not characterized by their mechanical and elastomeric properties at low temperatures.

[0010] U.S. Pat. No. 3,635,926 relates to the emulsion copolymerization of perfluorovinyl ethers with TFE, showing that the presence of —COF acylfluoride end groups makes the polymers unstable. The same phenomenon was already reported in U.S. Pat. No. 3,085,083 in the perfluorovinylether polymerization systems in solvent.

[0011] U.S. Pat. No. 3,817,960 relates to the preparation and polymerization of perfluorovinyl ethers having the formula

CF3O(CF2O)n″CF2CF2OCF═CF2

[0012] wherein n″ can range from 1 to 5. The compound synthesis is complex, it requires three steps. The preparation of the starting compound CF3O(CF2O)n″CF2C(O)F is carried out by oxidation at low temperature in the presence of U.V. radiations; besides the condensation with HFPO (hexafluoropropenoxide) and the subsequent alkaline pyrolisis is necessary. No characterization data on the above indicated properties are reported. With regard to this see patent application DE 19,713,806.

[0013] U.S. Pat. No. 3,896,179 relates to the separation of “primary” isomers of perfluorovinylether, for example of CF3CF2CF2OCF═CF2 from the corresponding less stable “secondary” isomers CF3(CF3)CFOCF═CF2. The latter are undesired products as regards both the polymer preparation and the poor properties of the obtained polymers.

[0014] U.S. Pat. No. 4,340,750 relates to the preparation of perfluorovinyl ethers having the formula

CF2═CFOCF2RofX1

[0015] wherein Rof is a C1-C20 perfluoroalkyl optionally containing oxygen, X1═H, Cl, Br, F, COORo, CONRoR wherein Ro is a C1-C10 alkyl group and R′ represents H or a C1-C10 alkyl group. In the preparation of these compounds an acylfluoride together with iodine and tetrafluoroethylene is used, avoiding the final step of the acylfluoride pyrolisis which comes from the perfluoro-propene epoxide, by a deiodofluorination reaction, which takes place with low yields.

[0016] U.S. Pat. No. 4,487,903 relates to the preparation of fluoroelastomeric copolymers using perfluorovinyl ethers having the formula:

CF2═CF(OCF2CFYo)noOX2

[0017] wherein n0 ranges from 1 to 4; Yo═F, Cl, CF3, H; X2 can be C1-C3 perfluoroalkyl group, C1-C3 &ohgr;-hydroperfluoroalkyl group, C1-C3 &ohgr;-chloroperfluoroalkyl group. The polymer has a content of fluorovinylether units content ranging from 15 to 50% by moles. These vinyl ethers give copolymers which at low temperatures have better properties than those of the above mentioned perfluorovinyl ethers PVE (perfluoropropylvinylether) and MVE type. In the patent it is disclosed that in order to have good properties at low temperature, the presence of at least two ether bonds in the side chain adjacent to the double bond is required. Furthermore from the patent it results that for n0 values higher than 4 it is difficult to purify the monomers and the effect on the decrease of the polymer Tg is lower. Besides the reactivity of the described vinyl ethers is very low and it is difficult to obtain polymers having a high molecular weight able to give good elastomeric properties for the indicated applications. A TFE /perfluorovinyl ether copolymer (no═2) 31/69% by weight with Tg of −32° C. is exemplified. However the polymer is obtained with very long reaction times (96 hours of polymerization). Also in this case no characterization data of the cured elastomer are given.

[0018] EP 130,052 describes the perfluorovinylpolyether (PVPE) polymerization which leads to amorphous perfluoropolymers with a Tg ranging from −15 to −100° C. The described polymers have Tg values reaching up to −76° C.; the further Tg decrease is obtained by using perfluoropolyethers as plasticizers. In the patent copolymers and terpolymers of TFE and KVE with vinylethers (PVPE) having the formula

CF2═CFO(CF2CF(CF3)0)n′″Rof,

[0019] are described, wherein n′″ ranges from 3 to 30 and Rof, is a perfluoroalkyl group. Due to purification difficulties, the used vinyl ethers are vinylether mixtures with different n′″ values. According to said patent the most evident effect on the Tg decrease is shown when n′″ is equal to or higher than 3, preferably higher than 4. According to the polymerization examples described in said patent the final mass of the polymer, besides the hot and under vacuum treatment, must then be washed with freon® TF in order to remove all the unreacted monomer (PVPE). From the Examples it results that the reactivity of all the described monomers (PVPE) is poor.

[0020] U.S. Pat. No. 4,515,989 relates to the preparation of new intermediates for the fluorovinylether synthesis. According to the patent the vinylether synthesis is improved by using an intermediate able to more easily decarboxylate. For its preparation fluoroepoxides of formula: 1

[0021] wherein X3═Cl, Br are used.

[0022] U.S. Pat. No. 4,766,190 relates to the polymerization of perfluorovinylpolyethers (PVPE) similar to those of U.S. Pat. No. 4,487,903 with TFE and low perfluoropropene percentages, in order to increase the mechanical properties of the obtained polymers.

[0023] EP 338,755 relates to the preparation of perfluorinated copolymers by using direct fluorination of partially fluorinated copolymers. More reactive partially fluorinated monomers are used, subjecting then the obtained polymers to fluorination with elemental fluorine. The fluorination step requires a supplementary process unit, besides in this step elemental fluorine is used, which is a highly oxidizing gas, with the consequent precautions connected to its use. Besides in the patent it is stated that in order not to compromise the fluorination reaction and the properties of the obtained polymer, using the invention process the percentage of the comonomer in the polymer cannot exceed 50% by moles.

[0024] U.S. Pat. No. 5,268,405 reports the preparation of perfluorinated rubbers having a low Tg, by using high viscosity perfluoropolyethers as plasticizers of perfluorinated rubbers (TFE/MVE copolymers). However during the use perfluoropolyether bleeds take place. This is true especially for the the PFPE having a low molecular weight (low viscosity): in said patent, therefore, the high viscosity PFPE use is suggested, and therefore the low viscosity PFPES must previously be removed.

[0025] U.S. Pat. No. 5,350,497 relates to the preparation of perfluoroalkylvinyl ethers by fluorination with elemental fluorine of hydrofluorochloroethers and subsequent dechlorination.

[0026] U.S. Pat. No. 5,401,818 relates to the preparation of perfluorovinyl ethers of formula:

R1f(OCF2CF2CF2)m, —OCF═CF2

[0027] (wherein R1f is a C1-C3 perfluoroalkyl radical and m′ is an integer ranging from 1 to 4) and of the corresponding copolymers having improved properties at low temperature. The preparation of said perfluorovinyl ethers is carried out by 7 steps, some of them have very low yields, and comprise also a perfluorination with elemental F2. The reactivity of said perfluorovinyl ethers is anyhow low.

[0028] As it is shown from the above reported prior art, the perfluorovinylether synthesis generally involves a multistep process with low yields (U.S. Pat. No. 3,132,123, U.S. Pat No. 3,450,684), with additional purifications to remove undesired isomers (U.S. Pat. No. 3,896,179) and the need to control the undesired hydrogenated by-products (U.S. Pat. No. 3,291,843). Alternatively, in the synthesis substances acting as intermediates, which are suitably prepared, and which allow to eliminate said drawbacks (U.S. Pat. No. 4,340,750, U.S. Pat No. 4,515,989), are used.

[0029] Furthermore in some cases the vinylether preparation requires the fluorination with elemental fluorine of partially fluorinated intermediates (U.S. Pat. No. 5,350,497); or, to avoid synthesis and low reactivity problems of the perfluorovinyl ethers, fluorination of partially fluorinated polymers (EP 338,755) is suggested.

[0030] Other problems shown in the prior art relate to the low reactivity of the perfluorovinyl ethers, which makes it necessary the recovery of the unreacted monomers from the reaction products (UK 1,514,700), and the stability problems for the polymers having —C(O)F end groups (U.S. Pat. No. 3,635,926). These last can be furtherly transformed by suitable reactants in order to increase the stability of the fluorinated polymer (EP 178,935).

[0031] Perfluorooxyalkylvinyl ethers are furthermore used to confer to the fluorinated rubbers good properties at low temperatures, and specifically to lower the glass transition temperature.

[0032] By increasing the perfluorooxyalkyl units forming the side perfluorooxyalkyl substituent, the Tg of the respective obtainable amorphous copolymers decreases, but at the same time the vinylether reactivity drastically decreases, making it difficult or impossible to obtain polymers having a sufficiently high molecular weight for giving to the polymers the desired elastomeric properties, and besides making more evident the problems previously shown for the recovery of the unreacted monomer from the polymerization raw products or from the polymer itself (U.S. Pat. No. 4,487,903- EP 130,052). In some cases, where the monomer cannot be completely removed by simple stripping under vacuum, more washings must then be carried out with fluorinated solvents for completely eliminating the unreacted vinylether from the polymer mass.

[0033] The amorphous copolymers of TFE with perfluoromethylvinylether have a Tg around 0° C. or slightly lower (Maskornik, M. et al. “ECD-006 Fluoroelastomer-A high performance engineering material”. Soc. Plast Eng. Tech. Pao. (1974), 20, 675-7).

[0034] The Tg extrapolated value of the MVE homopolymer is of about −5° C. (J. Macromol. Sci.-Phys., B1(4), 815-830, Dec. 1967).

[0035] In U.S. Pat. No. 5,296,617 and 5,235,074 there is described the hypofluorite CF2(OF)2 reactivity towards unsaturated products, which contemporaneously leads to the formation of the dioxolane derivative and to the fluorination compound of the olefin itself. In EP 683,181 there is described the CF2(OF)2 reactivity towards olefins which leads to the formation of linear reaction compound between one hypofluorite molecule and two molecules of the same olefin, for the preparation of symmetric dienes.

[0036] More specifically fluoroelastomers, suitable to the preparation of O-rings, based on monomeric units deriving from vinylidenfluoride (VDF), hexafluorapropene (HFP), perfluoroalkylvinyl ethers (PAVE) such as for example methylvinyl ether, and optionally tetrafluoroethylene (TFE), which are curable by ionic route, have high elastomeric properties at low and high temperatures and show good processability, at the mould release after curing (see U.S. Pat. No. 5,260,393). Said fluoroelastomers show improved properties with respect to the copolymers formed by VFD and HFP units, used in the O-ring preparation. In fact said last copolymers show good hot properties, but poor properties at low temperatures.

[0037] It is also known that fluoroelastomers having better cold properties are those based on VDF, PAVE and optionally TFE units, curable by radical route with peroxides and crosslinking agents.

[0038] By this kind of crosslinking, however, the process for producing manufactured articles is more complex with respect to the crosslinking of ionic type.

[0039] Fluoroelastomeric copolymers based on monomeric units deriving from vinylidenfluoride (VDF), which are curable by ionic route and suitable for the production of shaft seals and fuel hoses (see U.S. Pat. No. 5,260,392), are also known.

[0040] As it is known, the preparation of such manufactured articles requires elastomeric materials having an optimal combination of the following properties: good resistance properties to motor oils and/or petrols, good resistance properties at high temperatures as well as good cold behaviour and in particular, for the manufactured articles as shaft seals, good processability in both compression and injection moulding and also good curing rate.

[0041] It is known to use for such manufactured articles fluoroelastomeric copolymers formed by monomeric units of VDF, perfluoroalkylvinyl ethers (PAVE) and tetrafluoroethylene (TFE).

[0042] Said copolymers have good properties at low temperatures, however they show the drawback to be curable only by peroxidic route, with all the drawbacks due to said curing method, such as for example the need to carefully control the temperatures in the compounding operations, the short scorch and thermal activation times.

[0043] Fluoroelastomers having an improved processability and very good mechanical and elastic properties curable both by ionic and peroxidic route, are also known.

[0044] It is also known that an improvement in the fluoroelasomer processability is obtainable by suitably mixing polymers having a different molecular weight distribution. This inevitably implies, besides swelling phenomena after extrusion, a worsening in the mechanical properties and in the final product mouldability.

[0045] Said fluoroelastomers show an improved processability, especially during the blend calendering, combined with very good mechanical and workability properties during the extrusion and the injection moulding, together with a very good mould release. These fluoroelastomers are obtained by introducing in the polymer chain small amounts of a bis-olefin (see U.S. Pat. No. 5,585,449). The above described fluoroelastomers have however the drawback to show at low temperatures properties not yet able to satisfy the most urgent requirements of resistance at low temperatures, such as for example in car industry, wherein materials are required having the combination of the following properties:

[0046] chemical resistance to petrols additived with alcohols or MBTE or other polar compounds,

[0047] high resistance at low temperatures such as for example shown by TR 10 (ASTM D 1329 method),

[0048] very low Tg,

[0049] maintenance of good elastomeric properties, such as for example mechanical and sealing properties, in particular at high temperatures.

[0050] The Applicant has surprisingly and unexpectedly found that it is possible to solve the above technical problem as described hereinafter, by using special fluorovinyl ethers, which are furthermore easily synthetizable and obtainable by a continuous process.

[0051] An object of the present invention are fluoroelastomers that is elastomeric fluoropolymers, comprising in the polymer chain units deriving from fluorovinyl ethers of general formula:

CFX═CXOCF2OR  (I)

[0052] wherein R is a C2-C6 linear, branched or C5-C6 cyclic (per)fluoroalkyl group, or a C2-C6 linear, branched (per)fluorooxyalkyl group containing from one to three oxygen atoms; when R is a fluoroalkyl or fluorooxyalkyl group as above defined it can contain from 1 to 2 atoms, equal or different, selected from the following: H, Cl, Br, and I; X═F, H.

[0053] The fluorovinyl ethers of general formula:

CFX═CXOCF2OCF2CF2Y  (II)

[0054] wherein Y═F, OCF3; X is as above defined, are preferred among the compounds of formula (I).

[0055] The perfluorovinyl ethers of formula:

CF2═CFOCF2OCF2CF2Y  (III)

[0056] wherein Y is as above defined, are particularly preferred.

[0057] The perfluorovinylether having the formula:

CF2═CFOCF2OCF2CF3  (IV)

[0058] is still furtherly preferred.

[0059] Surprisingly, the vinyl ethers according to the invention show the advantages reported hereinafter with respect to the known vinyl ethers.

[0060] The obtainable advantages can be attributed to the —OCF2O— unit directly bound to the ethylene unsaturation.

[0061] The Tg lowering obtained with the vinyl ethers of the invention is connected to the presence of the (—OCF2O—) unit directly bound to the unsaturation. The Tg lowering is surprisingly so evident to be defined a primary effect.

[0062] In fact if the vinylether of the invention with two oxygen atoms is used:

CF2═CF—O—CF2—O—CF2CF3  (MOVE 1)

[0063] the Tg lowering, in copolymers with TFE having vinylether percentages of about 46% by weight is of 35° C. with respect to PVE

CF2═CF—O—CF2CF2CF3  (PVE)

[0064] and of 15° C. with respect to the vinylether having the same empirical formula, but with the second oxygen atom in a different position and without showing the characteristic unit (—OCF2O—)

CF2═CF—O—CF2CF2O—CF3  (&bgr;-PDE)

[0065] It is still more surprising to notice that with respect to MVE

CF2═CF—O—CF3

[0066] the &bgr;-PDE vinylether does not give any advantage as regards Tg.

[0067] On the contrary the primary effect of the (—OCF2O—) unit results very clear with the vinyl ethers of the invention (MOVE).

[0068] It has been found that the (—OCF2O—) unit bound to the ethylene unsaturation of the vinyl ethers of the invention increases the vinylether reactivity, reducing the rearrangements to COF which cause instability.

[0069] The advantages of the polymers of the invention can be summarized as follows:

[0070] The reactivity of the new monomers allows to prepare copolymers having a very low content of carboxylic groups or derivatives thereof such as —C(O)F, —COO—. The carboxylic group content in the copolymer with TFE has resulted of about 10 times lower than that of a copolymer prepared under the same conditions but using PVE instead of fluorovinyl ethers (see the Examples). As said, the presence of a lower content of carboxylic groups, or of the corresponding derivatives (amides, esters, etc.) allows to obtain more stable polymers.

[0071] The reactivity of the monomers of formula (I) is surprisingly high (see the Examples).

[0072] To obtain amorphous polymers the amount of the vinylether of the invention must be such to lead to the disappearance of the crystalline domains. That is, the polymer is substantially free of crystalline domains. The skilled man in the art can easily verify the amount of the vinyl ethers of the invention which is required for obtaining said results. Generally the amount of the vinylether for obtaining amorphous polymers is higher than 10% by moles, (i.e. 10 mole %) preferably in the range from about 15 to 20% by moles, or higher.

[0073] The properties at low temperature (Tg) of the polymers object of the invention result clearly better with respect both to copolymers having the same MVE content (see the Examples) and also, surprisingly, with respect to copolymers where the perfluorovinylether, the oxygen atoms being equal, does not show the —OCF2O— group directly bound to the unsaturation, as in the case of the CF2═CFOCF2CF2OCF3 (&bgr;-PDE)(see the Examples).

[0074] A further advantage of the fluorovinyl ethers (I) of the invention, as hereinafter illustrated, consists in that their preparation is carried out in a continuous manner by a limited number of steps. Furthermore the used raw materials are inexpensive. The following ones can for example be mentioned: CF2(OF)2, CF2═CF2, CF2═CFOCF3, CHC1═CFC1, CFC1═CFC1, CF2═CFC1, CF2═CFH, CF2═CH2, CHC1═CHC1 and other olefins.

[0075] The use of these reactants is specified in the synthesis process of the vinyl ethers of the invention.

[0076] The copolymers of the invention are obtainable by polymerizing with suitable comonomers, the fluorovinyl ethers of general formula (I)-(IV). To obtain the fluoroelastomers of the invention the amount of the comonomers of formula (I)-(IV) used in the comonomer mixture is such to lead to the disappearance of the crystalline domains. Generally the amount is higher than 10% by moles.

[0077] When used in connection with a quantity the term about refers to such normal variation in that quantity as would be expected by the skilled artisan.

[0078] As used herein, essentially free of crystalline zones or regions means that crystallinity is not detected by, for example, DSC, under typical ordinary conditions as would be used by the skilled artisan in routine experiments.

[0079] With copolymer, a polymer containing the vinyl ether of the invention and one or more comonomers, is meant.

[0080] Preferred comonomers are fluorinated compounds having at least one polymerizable carbon-carbon double bond C═C, optionally containing hydrogen and/or chlorine and/or bromine and/or iodine and/or oxygen.

[0081] Other comonomers that can be copolymerized withn the fluorovinyl ethers of the present invention are non fluorinated C2-C8 olefins, i.e. olefinically unsulated hydrocarbons such as ethylene, propylene, and isobutylene.

[0082] The following are some examples of suitable copolymerizable comonomers, as that term is used herein, and others will be in the contemplation of the skilled artisan:

[0083] C2-C8 perfluoroolefins, such as tetrafluoroethylene (TFE) hexafluoropropene (HFP), hexafluoroisobutene;

[0084] C2-C8 hydrogenated fluoroolefins, such as vinyl fluoride (VF), vinylidene fluoride (VDF), trifluoroethylene,

[0085] CH2═CH—R2f perfluoroalkylethylenes wherein R2f is a C1-C6 perfluoroalkyl;

[0086] C2-C8 chloro- and/or bromo- and/or iodo-fluoroolefins, such as chlorotrifluoroethylene (CTFE) and bromotri-fluoroethylene;

[0087] CF2═CFOR2f (per)fluoroalkylvinyl ethers (PAVE), wherein R2f is a C1-C6 (per)fluoroalkyl, for example trifluoromethyl, bromodifluoromethyl or heptafluoropropyl;

[0088] CF2═CFOXa (per)fluoro-oxyalkylvinyl ethers, wherein Xa is a C1-C12 alkyl, or a C1-C12 oxyalkyl, or a C1-C12 (per)fluorooxyalkyl having one or more ether groups, for example perfluoro-2-propoxy-propyl.

[0089] sulphonic monomers having the structure CF2═CFOXbSO2F, wherein Xb═CF2CF2, CF2CF2CF2, CF2CF(CFXC) wherein Xc═F, Cl, Br.

[0090] a bis-olefin having the general formula

RI1, RI2, C═CRI3,—Z—CRI4═CRI5RI6,  (IA)

[0091] wherein

[0092] RI1, RI2, RI3, RI4, RI5, RI6, equal to or different from each other, are H or C1-C5 alkyls;

[0093] Z is a C1-C18 linear or branched alkylene or cycloalkylene radical, optionally containing oxygen atoms, preferably

[0094] at least partially fluorinated, or a (per)fluoropolyoxy-alkylene radical.

[0095] In the formula (IA), Z is preferably a C4-C12 perfluoro-alkylene radical, while RI1 , RI2, RI3, RI4, RI5, RI6 are preferably hydrogen.

[0096] When Z is a (per) fluoropolyoxyalkylene radical, it preferably has the formula:

—(Q)p—CF2O—(CF2CF2O)ma(CF2O)na—CF2—(Q)p—  (IIA)

[0097] wherein:

[0098] Q is a C1-C10 alkylene or oxyalkylene radical;

[0099] p is 0 or 1;

[0100] ma and na are integers such that the ma/na ratio is comprised between 0.2 and 5 and the molecular weight of said (per)fluoropolyoxyalkylene radical is in the range from 500 to 10,000, preferably from 1,000 to 4,000.

[0101] Preferably, Q is selected from the following groups:

—CH2OCH2—; —CH2O(CH2CH2O)sCH2—,

[0102] with s =1-3.

[0103] The bis-olefins of formula (IA) wherein Z is an alkylene or cycloalkylene radical can be prepared according to what described, for example, by I. L. Knunyants et al. in Izv. Akad. Nauk. SSR, Ser. Khim. 1964(2), 384-6, while the bis-olefins containing (per)fluoropolyoxyalkylene sequences are described in USP 3,810,874.

[0104] The amount of units in the chain deriving from said bis-olefins is generally in the range 0.01-1.0 by moles.

[0105] The above indicated comonomers, polymerizable with perfluorovinyl ethers, can be used separately or in admixture with other comonomers.

[0106] The base structure of the fluoroelastomer can in particular be selected from:

[0107] (1) copolymers based on VDF, wherein the latter is copolymerized with at least one copolymerizable comonomer selected from:

[0108] C2-C8 perfluoroolefins such as tetrafluoroethylene (TFE), hexafluoropropene (HFP) C2-C8 chloro- and/or bromo and/or iodo-fluoroolefins, such as chlorotrifluoroethyethylene (CTFE) and bromotrifluoroethylene; CF2═CFORtf (per)fluoroalkylvinyl ethers (PAVE), wherein Rtf is a C1-C6 (per)fluoroalkyl, for example trifluoromethyl, bromodifluoromethyl, pentafluoropropyl; CF2═CFOXt perfluorooxyalkylvinyl ethers, wherein Xt is a C1-C12 perfluorooxyalkyl having one or more ether groups, for example perfluoro-2-propoxy-propyl; C2-C8 non fluorinated olefins (01), for example ethylene and propylene;

[0109] (2) copolymers based on TFE, where the latter is copolymerized with at least one copolymerizable comonomer selected from:

[0110] CF2═CFORtf (per)fluoroalkylvinyl ethers (PAVE), wherein Rtf is as above defined; CF2═CFOXt perfluorooxyalkylvinyl ethers, wherein Xt is as above defined; C2-C8 fluoroolefins containing hydrogen and/or chlorine and/or bromine and/or iodine atoms;

[0111] C2-C8 non fluorinated olefins (01).

[0112] Inside the above defined classes of fluoroelastomers, preferred base monomeric compositions (by moles) are the following: 1 VDF 45-85 HFP and/or PAVE  0-45 TFE  0-30 MOVE  1-45, preferably 5-40 01  0-40 the sum of HFP + PAVE + MOVE being at most 45%; TFE 50-85 PAVE  0-50 MOVE  1-50, preferably 5-40 01  0-40

[0113] the sum of PAVE+MOVE being at most 50.

[0114] The fluoroelastomers of the invention are preferably cured by peroxidic route.

[0115] When they are cured by ionic route, the preferred compositions (expressed by moles) are the following when the fluoroelastomer is used for the O-Ring preparation: 2 VDF 48-65 HFP 20-35 PAVE 0-6 TFE  0-20 MOVE 3-9

[0116] the SUM PAVE +MOVE lower than or equal to 10% by moles.

[0117] For the use of fluoroelastomers for obtaining shaft seals or fuel hoses the following compositions (by moles) are preferred: 3 VDF 30-47 HFP 20-40 PAVE  0-17 TFE 10-30 MOVE  3-20

[0118] the sum PAVE+MOVE lower than or equal to 20% by moles.

[0119] In the case of fluoroelastomers curable by peroxidic route, it is preferable to add small amounts of a bis-olefin as above mentioned.

[0120] In order to reach a good curing degree it is suitable to use fluoroelastomers containing reactive sites, i.e. iodine and/or bromine in chain, preferably iodine (cure site monomer).

[0121] Also an iodinated and/or brominated transfer agent can be used.

[0122] The process for the preparation of fluorinated polymers according to the present invention can be carried out by polymerization in organic solvent as described in U.S. Pat. Nos. 4,864,006 and 5,182,342, herein incorporated by reference. The organic solvent is selected from the group comprising chlorofluorocarbons, perfluoropolyethers, hydrofluorocarbons and hydrofluoroethers.

[0123] Alternatively the preparation of fluoroelastomers object of the present invention can be carried out by copolymerization of the monomers in aqueous emulsion according to well known methods in the prior art, in the presence of radical initiators (for example alkaline or ammonium persulphates, perphosphates, perborates or percarbonates), optionally in combination with ferrous, cuprous or silver salts, or of other easily oxidizable metals. In the reaction medium also surfactants of various type are usually present, among which the fluorinated surfactants of formula:

R3f—X−M+

[0124] are particularly preferred, wherein R3f is a C5-C16 (per)fluoroalkyl chain or a (per) fluoropolyoxyalkyl chain, X− is —COO− or —SO3−, M+is selected from: H+, NH4+, an alkaline metal ion. Among the most commonly used, ammonium perfluorooctanoate, (per)fluoropolyoxyalkylenes ended with one or more carboxylic groups, etc. can be mentioned.

[0125] See U.S. Pat. No. 4,990,283 and U.S. Pat. No. 4,864,006.

[0126] At the end of the polymerization, the fluoroelastomer is separated from the emulsion by conventional methods, such as coagulation by addition of electrolytes or by cooling.

[0127] Alternatively, the polymerization can be carried out in bulk or in suspension, in an organic liquid where a radical initiator is present, according to well known techniques.

[0128] The polymerization reaction is generally carried out at temperatures comprised between 25° C. and 150° C., under pressure up to 10 MPa.

[0129] The preparation of the fluoroelastomers of the present invention is preferably carried out in aqueous emulsion in the presence of an emulsion, dispersion or microemulsion of perfluoropolyoxyalkylenes, according to U.S. Pat. No. 4,789,717 and U.S. Pat. No. 4,864,006.

[0130] The fluoroelastomers of the present invention are preferably cured by peroxidic route, wherefore they preferably contain in the chain and/or in terminal position of the macromolecules iodine and/or bromine atoms, preferably iodine. The introduction of such iodine and/or bromine atoms can be carried out by addition, in the reaction mixture, of brominated and/or iodinated cure-site comonomers, such as bromo and/or iodo olefins having from 2 to 10 carbon atoms (as described for example in U.S. Pat. No. 4,035,165 and U.S. Pat. No. 4,694,045), or iodo and/or bromo fluoroalkylvinyl ethers (as described in patents U.S. Pat. No. 4,745,165, U.S. Pat. No. 4,564,662 and EP 199,138), in amounts such that the content of cure-site comonomers in the final product is generally in the range 0.05-2 moles for 100 moles of the other base monomeric units.

[0131] Alternatively or also in combination with cure-site comonomers, it is possible to introduce iodine and/or bromine end atoms by addition to the reaction mixture of iodinated and/or brominated chain transfer agents, such as for example compounds of formula Rbf(I)x(Br)y, wherein Rbf is a (per)fluoroalkyl or a (per)fluorochloroalkyl having from 1 to 8 carbon atoms, while x and y are integers comprised between 0 and 2, with 1≦x+y ≦2 (see for example patents U.S. Pat. No. 4,243,770 and U.S. Pat. No. 4,943,622).

[0132] It is also possible to use as chain transfer agents iodides and/or bromides of alkaline or alkaline-earth metals, according to U.S. Pat. No. 5,173,553.

[0133] Alternatively or in combination with the chain transfer agents containing iodine and/or bromine, other chain transfer agents known in the prior art, such as ethyl acetate, diethylmalonate, etc., can be used.

[0134] Curing by peroxidic route is carried out, according to known techniques, by addition of a suitable peroxide able to generate radicals by heating.

[0135] Among the most commonly used we remind: dialkylperoxides, such as for example di-terbutyl-peroxide and 2,5-dimethyl-2,5-di(terbutylperoxy)hexane; dicumyl peroxide, dibenzoyl peroxide; diterbutyl perbenzoate; di-[1,3-dimethyl-3-(terbutylperoxy)butyl]carbonate. Other peroxidic systems are described, for example, in European patent applications EP 136,596 and EP 410,351.

[0136] To the curing blend other compounds are then added, such as:

[0137] (a) curing coagents, in amounts generally in the range 0.5-10%, preferably 1-7%, by weight with respect to the polymer; among them: triallyl-cyanurate, triallyl isocyanurate (TAIC), tris(diallylamine)-s-triazine; triallylphosphite; N,N-diallyl-acrylamide;

[0138] N,N,N′,N′-tetraallyl-malonamide; tri-vinyl-isocyanurate; and 4,6-tri-vinyl-methyltrisiloxane, etc. are commonly used: TAIC is particularly preferred;

[0139] (b) a metal compound, in amounts in the range 1-15%, preferably 2-10%, by weight with respect to the polymer, selected from oxides and hydroxides of divalent metals, such as for example Mg, Zn, Ca or Pb, optionally combined with a weak acid salt, such as for example stearates, benzoates, carbonates, oxalates or phosphites of Ba, Na, K, Pb, Ca;

[0140] (c) other conventional additives, such as thickeners, pigments, antioxidants, stabilizers and the like.

[0141] The fluoroelastomers of the present invention can be cured by ionic route. Suitable well known in the art curing and accelerating agents are added to the curing blend, besides the above mentioned products at points (b) and (c). For example, as curing agents aromatic or aliphatic polyhydroxylated compounds, or derivatives thereof can be used, as described for example in EP 335,705 and U.S. Pat. No. 4,233,427. Among them it can in particular be mentioned: di-, tri- and tetra-hydroxybenzenes, naphthalenes or anthracenes; bisphenols wherein the two aromatic rings are linked each other by an aliphatic, cycloaliphatic or aromatic bivalent radical, or by one oxygen or sulphur atom, or also one carbonyl group. The aromatic rings can be replaced with one or more chlorine, fluorine, bromine atoms, or with carbonyl, alkyl, acyl.

[0142] As accelerants it can for example be used: ammonium, phosphonium, arsonium or antimony quaternary salts (see for example EP 335,705 and U.S. Pat. No. 3,876,654); amino-phosphonium salts (see for example U.S. Pat. No. 4,259,463); phosphoranes (see for example U.S. Pat. No. 3,752,787); the iminic compounds described in EP 182,299 and EP 120,462; etc. Also adducts between an accelerant and a curing agent can be used, see patents U.S. Pat. No. 5,648,429, U.S. Pat. No. 5,430,381, U.S. Pat. No. 5,648,430 herein incorporated by reference.

[0143] It is also possible to use systems of mixed, both ionic and peroxidic, curing, as described in EP 136,596.

[0144] The synthesis process of the new (per) fluorovinyl ethers, which comprises the initial reaction of the hypofluorite with a fluorinated olefin of formula R1R2C═CR3R4 to give the intermediate hypofluorite F—CR1R2—CR3R4—OCF2OF, the subsequent reaction of said compound with a second fluorinated olefin of formula R5R6C═CR7R8 to give the intermediate F—CR1R2—CR3R4—OCF2O—CR5R6—CR7R8—F which by dehalogenation or dehydrohalogenation leads to the new perfluorovinyl ethers.

[0145] The general scheme of the synthesis is the following:

a) CF2(OF)2+R1R2C=CR3R4→F−CR1R2−CR3R4−OCF2OF  (VI)

b) F−CR1R2−Cr3R4−OCF2OF=R5R6C2=C1R7R8- - - →F−CR1R2−CR3R4−OCF2O−C2R5R6−C1R7R8−F dehalogen./  (VII)

c) F−CR1R2−CR3R4−OCF20−C2R5R6−C1R7R8−F - - - →, /dehydrohalogen.

CFX=CXOCF2OR  (I)

[0146] In this synthesis scheme:

[0147] with reference to the formula of the compound (VII):

[0148] R1, R4, equal or different, are H, F; R2, R3, equal or different are H, Cl under the following conditions: (1) when the final reaction is a dehalogenation R2, R3═Cl, (2) when the final reaction is a dehydrohalogenation one of the two substituents R2, R3 is H and the other is Cl; R5, R6, R7, R8 are:

[0149] F, or one of them is a C1-C4 linear or branched perfluoroalkyl group, or a C1-C4 linear or branched perfluorooxyalkyl group containing from one to three oxygen atoms, or R5 and R7, or R6 and R8, are linked each other to form with C2 and C1 a C5-C6 cycle perfluoroalkyl group;

[0150] when one of the R5-R8, radicals is a C2-C4 linear or branched fluoroalkyl, or a C2-C4 linear or branched fluorooxyalkyl containing from one to three oxygen atoms, one or two of the other R5-R8 are F and one or two of the remainders, equal to or different from each other, are selected from H, Cl, Br, Iodine; when the substituents selected from H, Cl, Br, Iodine are two, they are both linked to the same carbon atom; when R5 and R7, or R6 and R8, are linked each other to form with C2 and C1 a C5-C6 cycle fluoroalkyl group, one of the two free substituents R6, R8 or R5, R7 is F and the other is selected from H, Cl, Br, Iodine.

[0151] the fluoroalkene used in the reaction a) is replaceable with that of the subsequent reaction b); in this case the meanings defined for the substituents of the R1-R4 group, and respectively of the R5-R8 group, are interchangeable each other, with the proviso that the position of each radical of each of the two groups R1-R4 and R5-R8 with respect to —OCF2O— on the chain of the intermediate compound (VII), is the same which is occupied if the synthesis takes place according to the above reported scheme and the two olefins each react in the considered steps.

[0152] In the first reaction a) of the above illustrated scheme a hypofluorite gas flow CF2(OF)2, suitably diluted with an inert fluid, comes into contact, in a suitable reactor with outlet, on the bottom of the same (first reactor), with a flow formed by the R1R2C═CR3R4 olefin, optionally diluted in an inert fluid, so as to allow the chemical reaction a) with formation of the intermediate hypofluorite (VI). To favour the reaction stoichiometry, the reactants must be introduced into the reactor in an approximately unitary molar ratio, or with an excess of CF2(OF)2. The residence time of the mixture in the reactor can range from few hundredths of second up to about 120 seconds depending on the olefin reactivity, the reaction temperature and the presence of optional reaction solvents.

[0153] The reaction temperature can range from −40° to −150° C., preferably from −80° to −130° C.

[0154] The compound (VI) usually is not separated from the reaction product and it is transferred in a continuous way to the subsequent reaction described in step b).

[0155] The mixture of the products coming out from the first reactor can be heated at room temperature before being fed into the second reactor.

[0156] In the second reaction b) the second olefin R5R6C═CR7R8 pure or in solution, reacts with the product obtained in the first reaction with formation of compound (VII).

[0157] The olefin can be fed in a continuous way, so as to maintain its concentration constant in the reactor. The temperature of the reaction b) can range from −20° to −130° C., preferably from −50° to −100° C. The olefin concentration is higher than or equal to 0.01 M, preferably the concentration is higher than 3 M, more preferably also the pure compound can be used.

[0158] The solvents used in steps a) and b) are perfluorinated or chlorohydrofluorinated solvents or hydrofluorocarbons. Examples of said solvents are: CF2Cl2, CFCl3, CF3CF2H, CF3CFH2, CF3CF2CF3, CF3CCl2H, CF3CF2Cl. In the reaction c) the compound (VII), dependently on the olefins used in steps a) and b), after distillation from the reaction raw product, is subjected to dechlorination or to dehydrochlorination to obtain the vinyl ethers of formula (I). This last step can be carried out by using reactions widely described in the prior art. The suitable selection of the substituents R1 to R8 in the two olefins used in the synthesis allows to obtain the vinyl ethers of the present invention.

[0159] Another object of the invention is a process wherein a hypofluorite of formula X1X2C(OF)2 wherein X1 and X2 equal or different are F, CF3, and two fluoroalkenes of formula respectively RA1RA2C═CRA3RA4 and RA5RA6C═CRA7RA8 wherein RA1RA8equal or different, are F, H, Cl, Br, I, —CF2OSO2F, —SO2F,—COF, C1-C5 linear or branched perfluoroalkyl or oxyperfluoroalkyl group, are reacted according to steps a) and b) of the above indicated scheme of synthesis, excluding the dehalogenation or dehydrohalogenation step, to obtain compounds of general formula (VIII)

F—CRA1RA2—CRA3RA4—OCF2O—CRA5RA6—CRA7RA8—F.

[0160] The following Examples are reported with the purpose to illustrate the invention and they do not limit the scope of the same.

[0161] In the Examples the thermogravimetric analysis TGA is carried out by using a 10° C./min rate.

EXAMPLE 1

[0162] Synthesis of CF3CF 2OCF2OCFClCF2Cl perfluoro-1-2,dichloro-3,5-dioxaheptane.

[0163] The used reactor is of cylindrical type, with a total volume of 300 ml and is equipped with magnetic dragging mechanical stirrer, turbine with recycle of the reacting gas placed at 20 cm from the reactor top, internal thermocouple, two internal copper pipes for the reactant feeding which end at about 1 mm from the turbine, and product outlet from the bottom. In the reactor, inside which the temperature is maintained at −114° C., 1.1 1/h (litres/hour) of CF2(OF)2 and 3.3 1/h of He are introduced through one of the two inlet pipes; A flow of 1.1 1/h of CF2═CF2 and 0.7 1/h of He is maintained through the second inlet pipe. Feeding is continued for 6.6 hours.

[0164] The residence time of the transport gas in the reaction zone comprised between the outlet of the two feeding pipes in the reactor and the inlet of the discharge pipe is of about 4 sec.

[0165] On the reactor bottom the reaction products are brought again to room temperature and the gaseous mixture flow, monitored by gaschromatography, is fed in a continuous way, under mechanical stirring, into a second reactor having a 250 ml volume maintained at the temperature of —70° C., equipped with mechanical stirrer, thermocouple, dipping inlet for the reacting mixture, outlet with head of inert gas. The reactor contains 72.6 g of dichlorodifluoroethylene CFCl═CFCl.

[0166] At the end of the addition of reacting gases into the second reactor, the reaction raw material is distilled by a plate column at atmospheric pressure, collecting 41.5 g of the desired product (boiling point 91° C.).

[0167] The yield of perfluoro-1,2 dichloro-3,5-dioxaheptane, calculated with respect to CF2(OF)2, is of 36%.

[0168] Characterization of perfluoro 1,2, dichloro-3,5-dioxaheptane.

[0169] Boiling point at atmospheric pressure: 91° C.

[0170] 19F-NMR spectrum in p.p.m. (with respect to CFCl3=0):

[0171] −51.3/−53.0 (2F, O—CF2—O); −70. 6/−72.6 (2F, C—CF2Cl);

[0172] −78.0/−78.4 (1F, O—CFC1—C); −87.8 (3F, CF3—C):

[0173] −90.2 /−91.8 (2F, C—CF2—O).

[0174] Mass spectrum (E.I. electronic impact), main peaks and respective intensities:

[0175] 69 (48.6%); 119 (84.3%); 151 (76.8%); 153 (69.8%); 185 (100%).

[0176] IR spectrum (cm−1) intensity: (w)=weak, (m)=medium, (s)=strong, (vs)=very strong:

[0177] 1407.3 (w); 1235.8 (vs); 1177.7 (vs); 1097.5 (vs); 1032.2 (s); 929.3 (w); 847. 9 (m)

EXAMPLE 2

[0178] Synthesis of CF3OCF2CF2OCF2OCFClCF2Cl perfluoro-1,2-dichloro3,5,8-trioxanonane (isomer A) and of CF3OCF(CF3) OCF2OCFClCF2Cl perfluoro-1,2-dichloro-3,5,7-trioxa-6-methyloctane (isomer B)

[0179] In a reactor identical to that used in Example 1, maintained at the same temperature of −114° C., 1.55 1/h of CF2(OF)2 and 4.5 1/h of He are introduced through one of the two inlet pipes; through the second inlet pipe 1.4 1/h of CF2═CF—OCF3 and 0.7 1/h of He for 4.5 hours.

[0180] The residence time of the transport gas in the reaction zone comprised between the reactor outlet and the end of the two feeding pipes is of about 3 sec.

[0181] On the reactor bottom the reaction products are brought to room temperature and the gaseous mixture flow, monitored by gaschromatography, is fed in a continuous way, under mechanical stirring, into a second reactor identical to the one used for the same step in Example 1. Inside, where a temperature of −70° C. is maintained, there are 51 g of dichlorofluoroethylene CFCl═CFCl.

[0182] At the end of the addition of the reacting gases into the second reactor, the reaction raw material is distilled by a plate column at the reduced pressure of 250 mmHg. 50 g of a mixture formed by two isomers, respectively, isomer A) perfluoro-1,2-dichloro-3,5,8-trioxanonane and isomer B) perfluoro-1,2-dichloro-3,5,7-trioxa-6-methyloctane are collected. The mixture composition is determined by gaschromatography and is the following: isomer A 79%, isomer B 21%. The molar yield of A+B with respect to the used CF2(OF)2 is 38%. The molar yield of A+B with respect to the used perfluoromethylvinylether is 42%. The isomers have been separated by preparative gaschromatography.

[0183] Characterization of products A and B

[0184] Mixture boiling point (A 79%, B 21%) at the reduced pressure of 250 mmHg: 82° C.

[0185] 19F-NMR spectrum in p.p.m. (with respect to CFCl3=0) of the isomer A: 4 −50.6/−52.4(2F, O—CF2—O) −70.0/−71.8(2F, C—CF2Cl); −77.7(1F, O—CFCl—C); −55.3/−55.6(3F, CF3—OC); −90.7/−91.1(2F, C—OCF2—C) −90.2/−90.6(2F, C—OC—CF2OCOC).

[0186] 19F-NMR spectrum in p.p.m. (with respect to CFCl3=0) of isomer B: 5 −50.0/−52.1(2F, O—CF2—O)  −70.0/−71.8(2F, C—CF2Cl) −77.9(IF, O—CFCl—C);  −54.6/−54.9(3F, CF3OC): −85.7/−86.1(3F, OC(CF3)O) −100.3/−101.0(IF, OCF(C)O).

[0187] Mass spectrum (electronic impact), main peaks and respective intensities:

[0188] Product A: 69 (50); 119 (100); 151 (50); 185 (42); 251 (38);

[0189] Product B: 69 (96); 97 (50); 135 (42); 151 (92); 185 (100).

[0190] IR spectrum (cm−1) intensity of the mixture A 79%, B 21%: (w)=weak, (m)=medium, (s)=strong, (vs)=very strong: 1388 (w); 1288 (vs); 1233 (vs); 1151 (vs); 1104 (vs); 1032 (s); 846 (m); 685 (w)

EXAMPLE 3

[0191] Synthesis of CF3OCF2CF2OCF2OCHClCHFCl perfluoro-1 2-dichloro-1,2-dihydro-3,5,8-trioxanonane (isomer C) and of CF3OCF(CF3)OCF2OCHClCHFC1 perfluoro-1,2-dichloro-1,2-dihydro-3,5,7-trioxa-6-methyloctane (isomer D).

[0192] In a reactor identical to that used in Example 1, maintained at the temperature of −112° C., 1.55 1/h of CF2(OF2, and 4.5 1/h of He are introduced through one of the two inlet pipes; through the second inlet pipe 1.4 1/h of CF2═CF—OCF3 and 0.7 1/h of He for 5 hours.

[0193] The residence time of the transport gas in the reaction zone comprised between the reactor outlet and the end of the two feeding pipes is of about 3 sec.

[0194] On the reactor bottom the reaction products are brought again to room temperature and the gaseous mixture flow, monitored by gaschromatography, is fed in a continuous way, under mechanical stirring, into a second reactor identical to the one used for the same step in Example 1. Inside, the temperature is of −70° C. and there are 50 g of 1,2-dichloroethylene CClH═CClH and 50 g of CFC13.

[0195] At the end of the addition of the reacting gases into the second reactor, after distillation of the solvent at room pressure, the reaction raw material is distilled by a plate column at the reduced pressure of 100 mmHg. 43.5 g of the mixture of the desired products (isomer C 78%, isomer D 22%, determined by gaschromatography) are collected. The molar yield of C+D with respect to the used CF2(OF) 2 is 33%. The isomers have been separated by preparative gaschromatography.

[0196] Characterization of products C and D

[0197] Mixture boiling point (C 78%, D 22%) at the reduced pressure of 100 mmHg: 71° C.

[0198] 19F-NMR spectrum in p.p.m. (with respect to CFCl3=0) of the isomer C perfluoro-1,2-dichloro-1,2-dihydro-3,5,8-trioxanonane: 6 −56.0/−57.2(2F, O—CF2—O); −143.2/−146.0(1F, C—CHFCl); −55.8(3F, CF3—OC);  −91.0/−91.4(2F, −90.3/−90.5(2F, C—OC—CF2OCOC). C—OCF2—C);

[0199] 19F-NMR spectrum in p.p.m. (with respect to CFCl3=0) of the isomer D perfluoro-1,2-dichloro-1,2-dihydro-3,5, 7-trioxa-6-methyloctane: 7  −56.0/−57.2(2F, O—CF2—O); −143.2/−146.0(1F, C—CHFCl);  −54.9/−55.1(3F, CF3—OC);  −86.2/−86.3(3F, OC(CF3)O); −100.5/−101.0(1F, OCF(C)O).

[0200] 1H spectrum in p.p.m. (with respect to TMS) of the isomers C and D: 6.28/6.05 (1H -CHFC1); 6.02/5.95 (1H —CHC1—)

[0201] Mass spectrum (electronic impact), main peaks and (respective intensities %): 69 (84); 119 (100); 185 (51.1); 251 (84); 281 (15.8); 283 (4.8); 347 (5.7); 349 (1.7).

[0202] IR spectrum (cm−1) intensity: (w)=weak, (m)=medium, (s)=strong, (vs)=very strong:

[0203] 3001.0 (w); 2920.9 (w); 2850.9 (w); 1286.3 (vs); 1233.7 (vs); 1125.5 (vs); 1081.8 (S); 1047.9 (s); 815.9(m); 766.3 (m)

EXAMPLE 4

[0204] Dehalogenation of perfluoro 1,2-dichloro-3,5-dioxaheptane

[0205] In a 25 ml three-necked flask, equipped with mechanical stirrer, thermometer, dropping funnel, distillation column equipped with water refrigerant and collecting trap maintained at −78° C. and connected to a mechanical vacuum pump, 150 ml of DMF, 15 g of Zn in powder, 0.5 g of K2CO3 and 100 mg of 12 are introduced. The internal temperature is brought to 80° C. and 50 g of perfluoro -1,2-dichloro-3,5-dioxaheptane are added drop by drop.

[0206] When the addition is over it is allowed to react for about 30 minutes. At the end the internal pressure is gradually brought from starting 760 mmHg to 300 mmHg. After about 20 minutes the collecting trap containing 34.2 g of perfluoro-3,5-dioxa-l-heptene (MOVE 1) is disconnected.

[0207] The dehalogenation yield is 85%.

[0208] Characterization of perfluoro-3,5-dioxa-l-heptene (MOVE 1)

[0209] Boiling point at atmospheric pressure: 41.9° C.

[0210] 19F-NMR spectrum in p.p.m. with respect to CFC13=0: 8  −56.8(2F, O—CF2—O);  −87.2(3F, CF3—C);  −90.6(2F, C—CF2—O); −114(IF, O—C═C—F); −121.8(1F, O—C═CF); −137(IF, O—C—F═C);

[0211] Mass spectrum (electronic impact) main peaks and respective intensities: 69 (66.5%); 119 (100%); 147 (83.4%); 185 (89.4%); 216 (67.3%); 282 (8.2%).

[0212] IR spectrum (cm−1) intensity: (w)=weak, (m)=medium, (s)=strong, (vs)=very strong:

[0213] 1839.5 (m); 1407.6 (w); 1307.4 (vs); 1245.8 (VS); 1117.4 (VS) 907.2 (m); 846.0 (m)

EXAMPLE 5

[0214] Dehalogenation of the isomer mixture A+B obtained in Example 2 perfluoro-1,2-dichloro-3,5,8-trioxanonane CF3OCF2CF2CF2OCFClCF2Cl+perfluoro-1,2-dichloro-3,5,7-trioxa-6-methyloctane CF3OCF (CF3)OCF2OCFClCF2Cl).

[0215] In a 250 ml flask equipped as described in the previous Example 4, 110 Ml of DMF, 10 g of Zn in powder and 0.3 ml of Br2 are introduced. The internal temperature is brought to 75° C. and 30.3 g of the binary mixture A+B separated in the previous Example 2 are added drop by drop. When the addition is over the mixture is allowed to ract for about 3 hours. At the end the internal pressure is gradually lowered from 760 mmHg to 200 mmHg at −79° C. After about 30 minutes the collecting trap is disconnected. The corresponding content, which is washed with water, is recovered. At the end 24.0 g of a mixture formed for 79% (gaschromatographic determination) by perfluoro-3,5,8-trioxa-l-nonene (MOVE 2) CF3OCF2CF2OCF2OCF═CF2 (isomer A′) and for 21% by perfluoro-3,5,7-trioxa-6,methyl-1 octene (MOVE 2a) CF2OCF(CF3)OCF2O—CF═CF2 (isomer B′) are obtained, which are then separated by preparative gaschromatography.

[0216] Characterization of products A′ and B′

[0217] Boiling range of the isomer mixture at atmospheric pressure: 72.50-74.5° C.

[0218] 19F-NMR spectrum in p.p.m. (with respect to CFC13═O) of the isomer A′:

[0219] −55.9 (3F, CF3—O); −56.9 (2F, O—CF2—O); −90.8 (2F, C—CF2—O); −91.2 (2F, O—CF2—C); —114 (IF, O—C═C—F); —121.8 (IF,—O—C═CF); −137 (IF, O—CF═C)

[0220] 19F-NMR spectrum in p.p.m. (with respect to CFC13═O) of the isomer B′:

[0221] −55.9 (3F, CF3—O); −56.2 (2F, O—CF2—O); −86.4 (3F, CF3—C)

[0222] −100.9 (1F, CF; −114 (lF, O—C═C—F); -122 (iF, O—C═CF); -137 (1F, O—CF═C).

[0223] Mass spectrum (electronic impact), main peaks and respective intensities of the isomer A′: 69 (74); 81 (18); 119 (100); 147 (59); 185 (26); 251 (21);

[0224] Mass spectrum (electronic impact), main peaks and respective intensities of the isomer B′: 69 (80); 81 (37); 97 (47); 119 (36); 147 (100); 185 (19).

[0225] IR spectrum (cm−1), intensity: (w)=weak, (m)=medium, (s)=strong, (vs)=very strong, 1839 (m); 1343 (s); 1248 (vs); 1145 (vs); 918 (m); 889 (m)

EXAMPLE 6

[0226] Dehalogenation of the isomers C+D mixture obtained in Example 3 CF3OCF2CF2OCF2OCHClCHFCl perfluoro-1,2-dichloro-1,2-dihydro-3,5,8-trioxanonane (isomer C)+CF3OCF(CF3) OCF2OCHClCHFCl perfluoro-1,2-dichloro-1,2-dihydro-3,5,7-trioxa-6-methyloctane (isomer D).

[0227] In a 500 ml volume three-necked flask, equipped with mechanical stirrer, thermometer, dropping funnel, distillation column having a water refrigerant and a collecting trap maintained at the temperature of −78° C., 250 ml of DMF, 30 g of zinc in powder and 300 mg of 2 are introduced.

[0228] The temperature is brought to 100° C. and 56.9 g of the isomer mixture obtained in Example 3 are added drop by drop.

[0229] When the addition is over the reactor internal temperature is brought to 120° C. and stirring is maintained for 24 hours. At the end the reaction product, which contains traces of solvent and which is collected in the trap maintained at −78° C., is distilled. After washing with water 35 g of a mixture of perfluoro-1,2-dihydro-3-5-8-trioxa-l-nonene (isomer C′, 79% by moles) and of perfluoro-1,2-dihydro-3-5-7-trioxa-5-methyl-1-octene (isomer D′, 21% by moles) are recovered. The isomers are separated by preparative gaschromatography.

[0230] The dehaloagenation reaction yield is 76%.

[0231] Characterization of products C′ and D′

[0232] Boiling range of the mixture of isomers C′ 79%, D′ 21% at atmospheric pressure: 90.00-92.0° C.

[0233] 19F-NMR spectrum in p.p.m. (with respect to CFCl3═O) of the isomer C, perfluoro-1,2-dihydro-3,5,8-trioxa-l-nonene: 9  −55.7(3F, CF3—O); −57.3(2F, O—CF2—O);  −90.9(2F, C—CF2—O); −91.2(2F, O—CF2—C); −149.3/−150.0(1F, O—C═C—F).

[0234] 19F-NMR spectrum in p.p.m. (with respect to CFCl3═O) of the isomer D′ perfluoro-1,2-dihydro-3,5,7-trioxa-6-methyl-l-octene: 10  −55.0(3F, CF3—O);  −56.9(2F, O—CF2—O);  −86.2(3F, CF3—C); −101.0(1F, CF). −149.3/−150.0(1F, O—C═C—F)

[0235] Mass spectrum (electronic impact), main peaks and respective intensities): 69 (82); 119 (100); 185 (29); 246 (25); 251 (20); 312 (43).

[0236] IR spectrum (cm−1) intensity of the isomer mixture (C′ 79%, D′ 21%): (w)=weak, (m)=medium, (s)=strong, (vs)=very strong: 3140 (w); 1722 (w); 1695 (w); 1402 (m); 1281 (vs); 1237 (vs) 1147 (vs); 1106 (vs); 1030 (m)

EXAMPLE 7

[0237] Homopolymerization of perfluoro-3, 5-dioxa-1-heptene (MOVE 1)

[0238] In a glass reactor for polymerizations, having a 20 ml volume, equipped with magnetic stirring and with an inlet for the reactant feeding and discharge, 60 &mgr;l of perfluoropropionylperoxide at 3% by weight in CFC12CF2Cl and 3 g of MOVE 1 are in sequence introduced. The so charged reactor is brought to the temperature of −196° C., evacuated, brought to room temperature, the all twice. At the end of the degassing operations the reactor is thermostated at the temperature of 30° C. and it is allowed to react under these conditions for two days under magnetic stirring.

[0239] The reaction raw material which is finally recovered appears as a slightly viscous, transparent, colourless and homogeneous solution.

[0240] After distillation of the unreacted monomer, and subsequent stripping under vacuum at 150° C. for 3 hours, 180 mg of the polymer are separated.

[0241] The IR analysis of the obtained polymer shows that, in the spectrum absorption bands in the zone of the fluorinated double bonds are absent.

[0242] The 19F-NMR analysis carried out on the polymer dissolved in C6F6 is in accordance with the homopolymer structure having a molecular weight of 50,000. The analysis does not show the presence of unreacted monomer.

[0243] The DSC graph does not show any melting endothermic curve, wherefore the polymer is amorphous. The polymer Tg determined by DSC, is −35.4° C. The thermogravimetric analysis (TGA) shows a weight loss of 2% at 332° C. and of 10% at 383° C.

EXAMPLE 8

[0244] Copolymer between perfluoro-3,5,8-trioxa-l-nonene CF3OCF2CF2OCF2OCF═CF2 (MOVE 2) and perfluoro-3,5,7-trioxa-6, methyl-1-octene CF3OCF(CF3)OCF2O—CF═CF2 (MOVE 2a).

[0245] In a reactor having the same characteristics as that described in Example 7, 150 &mgr;l of perfluoropropionyl-peroxide at 3% by weight in CFCl2CF2Cl and 3.2 g of a mixture prepared according to the process of Example 5 and containing 83% MOVE 2 and 17% MOVE 2a, are introduced. The reactor is then evacuated, cooled, and the subsequent reaction carried out as described in the previous Example 7.

[0246] The reaction raw material appears as a slightly viscous, transparent, colourless and homogeneous solution. The monomers which have not reacted are distilled and a stripping under vacuum at 150° C. for 3 hours is in sequence carried out. Finally 350 mg of the polymer are separated.

[0247] The IR analysis shows that in the polymer spectrum, absorption bands in the zone of the fluorinated double bonds are absent.

[0248] The 19F-NMR analysis is in accordance with the copolymer structure having an average molecular weight of 35,000 and a MOVE 2/MOVE 2a content equal to the percentages of the reacting mixture; unreacted monomers are not evident.

[0249] The DSC graph does not show any melting endothermic curve, wherefore the polymer is amorphous. The polymer Tg, determined by DSC, is −52.6° C. The thermogravimetric analysis (TGA) shows a weight loss of 2% at 280° C. and of 10% at 327° C.

EXAMPLE 9

[0250] Amorphous copolymer between MOVE 1 and TFE.

[0251] In an AISI-316 polymerization reactor having a 40 ml volume, equipped with magnetic stirring, pressure transducer and an inlet for the reactant feeding and discharge, 250 &mgr;l of perfluoropropionylperoxide at 3% by weight in CFC12CF2Cl, 9.8 mmoles of MOVE 1 and 18 mmoles of tetrafluoroethylene are introduced.

[0252] The reactor is cooled to the temperature of −196° C., evacuated, then brought to room temperature and cooled again, the all twice.

[0253] At the end of the degassing operations the reactor is thermostated at the temperature of 30° C. and the reaction mixture maintained under magnetic stirring. The internal pressure decreases from 6.4 atm to 4.7 atm in about 8 hours (reaction time).

[0254] After distillation of the unreacted monomers, and polymer stripping under vacuum for 3 hours at 150° C., 1,100 mg of polymer are recovered, which appears as a transparent and colourless rubber.

[0255] By 19F-NMR analysis of the polymer dissolved under heating in C6F6 it is determined that the MOVE 1 molar percentage in the polymer is 24%.

[0256] The IR analysis does not show in the polymer spectrum absorption bands in the zone of the fluorinated double bonds, and shows the presence of very small absorption bands in the zone of the carboxyl signals. The intensity of these signals, compared with the similar ones obtained from a film having the same thickness obtained with the polymer of the comparative Example 1, is equal to about {fraction (1/10)} of these latter.

[0257] The DSC graph does not show any melting endothermic curve, wherefore the polymer is amorphous. The Tg determined by DSC is −21.4° C.

[0258] The TGA shows a weight loss of 2% at 450° C. and of 10% at 477° C. The polymer therefore results thermally more stable with respect to the comparative Example (see afterwards).

[0259] The polymer intrinsic viscosity measured at 30° C. in Fluorinert® FC-75, is 35.5 ml/g.

EXAMPLE 10

[0260] Amorphous co-polymer between MOVE 1 and TFE.

[0261] In an AISI-316 polymerization reactor identical to that described in the previous Example 9, 250 &mgr;l of perfluoropropionylperoxide at 3% by weight in CFC12CF2Cl, 9.75 mmoles of MOVE 1 and 9 mmoles of tetrafluoroethylene are in sequence introduced.

[0262] The procedure already described in the previous Example 9 is then followed until the thermostating step at the temperature of 30° C. under magnetic stirring. During the reaction the internal pressure decreases from 3.4 atm to 2.9 atm in about 8 hours.

[0263] At the end the unreacted monomers are distilled and the polymer is stripped under vacuum at 150° C. for 3 hours.

[0264] 480 mg of the polymer are separated.

[0265] By 19F-NMR analysis of the polymer dissolved under heating in C6F6 it is determined that the MOVE 1 molar percentage in the polymer is 39%.

[0266] The IR analysis shows that in the polymer spectrum absorption bands in the zone of the fluorinated double bonds are absent.

[0267] The DSC graph does not show any melting endothermic curve, wherefore the polymer is amorphous. The Tg determined by DSC is −29.8° C.

[0268] The TGA shows a weight loss of 10% at 435° C.

EXAMPLE 11

[0269] Amorphous copolymer between MOVE 1 and CF2═CH2

[0270] In a polymerization reactor identical to that described in Example 9, 250 &mgr;l of perfluoropropionylperoxide at 3% by weight in CFC12CF2Cl 10 mmoles of MOVE 1 and 18 mmoles of VDF are in sequence introduced.

[0271] The procedure already described in the previous Example 9 is followed until the thermostating step at the temperature of 30° C. under magnetic stirring. The internal pressure decreases from 6.8 atm to 5.0 atm during the reaction (about 8 hours).

[0272] After distillation of the unreacted monomers, and subsequent polymer stripping under vacuum at 1500C for 3 hours, 1,600 mg of the polymer are separated, appearing as a transparent and colourless rubber.

[0273] By the 19F-NMR analysis carried out on the polymer dissolved in C6F6 it is determined that the MOVE 1 molar percentage in the polymer is 40%.

[0274] The DSC graph does not show any melting endothermic curve, wherefore the polymer is amorphous. The Tg determined by DSC, is −47° C.

[0275] The TGA shows a weight loss of 2% at 428° C. and of 10% at 455° C.

EXAMPLE 12

[0276] Amorphous terpolymer MOVE 2/MOVE 2a/TFE.

[0277] In a polymerization reactor identical to that described in Example 9, 100 &mgr;l of perfluoropropionyl-peroxide at 6% by weight in CFC12CF2Cl, 10 mmoles of a MOVE 2 83% and MOVE 2a 17% mixture sinthetized according to the process of Example 5, and 18 mmoles of tetrafluoroethylene (TFE) are in sequence introduced.

[0278] The procedure already described in the previous Example 9 is then followed until thermostating at the temperature of 30° C. under magnetic stirring. The internal pressure decreases from 6.1 atm to 3.9 atm during the reaction (about 8 hours).

[0279] After distillation of the unreacted monomers and polymer stripping under vacuum at 150° C. for 3 hours, the polymer is separated.

[0280] By the 19F-NMR analysis carried out on the polymer dissolved in C6F6 it results that the total molar percentage of the MOVE 2+MOVE 2a perfluorovinyl ethers in the polymer is 22%; the MOVE 2/MOVE 2a ratio by moles in the polymer is 83/17 and it is equal to that of the starting fed mixture.

[0281] The presence of unreacted monomers is not evident.

[0282] The IR analysis does not show in the polymer spectrum absorption bands in the zone of the fluorinated double bonds, and it shows the presence of very small absorptions in the zone of the carboxyl signals. The intensity of these signals, compared with the similar ones obtained from a film having the same thickness obtained with the polymer of the comparative Example 1, is equal to about {fraction (1/10)} of the latter.

[0283] The DSC graph does not show any melting endothermic curve, wherefore the polymer is amorphous. The Tg determined by DSC, is −37.5° C.

[0284] The TGA shows a weight loss of 10% at 473° C.

[0285] The polymer intrinsic viscosity measured at 30° C. in Fluorinert® FC-75, is 40.0 ml/g.

EXAMPLE 13

[0286] Amorphous terpolymer MOVE 2/MOVE 2a/TFE.

[0287] In a polymerization reactor identical to that described in Example 9, 100 &mgr;l of perfluoropropionylperoxide at 6% by weight in CFC12 CF2Cl, 9.7 mmoles of the MOVE 2 (83%) and MOVE 2a (17%) mixture sinthetized according to the process of Example 5, and 10 mmoles of tetrafluoroethylene (TFE) are in sequence introduced.

[0288] The procedure already described in the previous Example 9 is then followed until the thermostating step at the temperature of 30° C. under magnetic stirring. The internal pressure decreases from 3.6 atm to 2.7 atm during the reaction course (about 8 hours).

[0289] After distillation of the unreacted monomers and polymer stripping under vacuum at 150° C. for 3 hours 652 mg of polymer are separated.

[0290] By the 19F-NMR analysis carried out on the polymer dissolved in C6F6 it results that the total molar percentage of the MOVE 2+MOVE 2a perfluorovinyl ethers in the polymer is 37%; the MOVE 2/MOVE 2a molar ratio in the polymer is 83/17 and it is equal to that of the starting fed mixture.

[0291] The presence of unreacted monomers is not evident.

[0292] The IR analysis does not show in the polymer spectrum absorption bands in the zone of the fluorinated double bonds.

[0293] The DSC graph does not show any melting endothermic curve, wherefore the polymer is amorphous. The Tg determined by DSC, is −44.5° C.

[0294] The TGA shows a weight loss of 10% at 451° C.

[0295] The polymer intrinsic viscosity measured at 30° C. in Fluorinert® FC-75, is 16.7 ml/g.

EXAMPLE 14

[0296] Amorphous copolymer between perfluoro-1,2-dihydro-3,5,8-trioxa-l-nonene (H-MOVE 2) and perfluoro-1,2-dihydro-3,5, 7-trioxa-6-methyl-l-octene (H-MOVE 2a) with molar ratio 88/12.

[0297] In a reactor identical to that described in Example 7, 200 &mgr;l of perfluoropropionylperoxide at 3% by weight in CFCl2—CF2Cl and 3.1 g of a H-MOVE 2/H-MOVE 2a 88/12 mixture are introduced.

[0298] The procedure described in Example 7 is followed.

[0299] The recovered reaction raw material appears as a slightly viscous, transparent, colourless and homogeneous solution.

[0300] After distillation of the unreacted monomer and subsequent stripping under vacuum at 150° C. for 3 hours, 120 mg of polymer are separated.

[0301] The IR analysis of the obtained polymer shows that in the polymer spectrum absorption bands in the zone of the fluorinated double bonds are absent.

[0302] The 19F-NMR analysis is in accordance with the copolymer structure having a content of monomers H-MOVE 2 and H-MOVE 2a equal to the H-MOVE 2 and H-MOVE 2a percentages in the reacting mixture. The analysis does not show the presence of unreacted monomers. The DSC graph does not show any melting endothermic curve, wherefore the polymer is amorphous. The polymer Tg. determined by DSC, is —58.0° C. The thermogravimetric analysis (TGA) shows a weight loss of 10% at 307° C.

EXAMPLE 15

[0303] Terpolymer H-MOVE 2/H-MOVE 2a/TFE.

[0304] In a reactor similar to that described in Example 9, 100 &mgr;l of perfluoropropionylperoxide at 6% by weight of CFCl2—CF2Cl and 5 mmoles of a H-MOVE 2 (88%) and H-MOVE 2a (12%) mixture and 18 mmoles of tetrafluoroethylene, are introduced.

[0305] The same procedure described in Example 9 is followed.

[0306] At the end of the degassing, the reactor is thermostated at the temperature of 30° C. under magnetic stirring. The internal pressure decreases from 6.8 atm to 6.5 atm in about 6 hours (reaction time).

[0307] After distillation of the unreacted monomers, and polymer stripping under vacuum at 150° C. for 3 hours, 300 mg of the polymer are separated.

[0308] By 19F-NMR analysis of the polymer dissolved under heating in C6F6 it is calculated that the molar percentage of the perfluorovinyl ethers (H-MOVE 2+H-MOVE 2a) contained in the polymer is 33%. The H-MOVE 2/H-MOVE 2a molar ratio in the polymer is equal to the H-MOVE 2/H-MOVE 2a molar ratio of the fed mixture. Unreacted monomers are not evident.

[0309] The IR analysis does not show in the polymer spectrum absorption bands in the zone of the fldorinated double bonds.

[0310] The DSC graph does not show any melting endothermic curve wherefore the polymer is amorphous. The Tg determined by DSC, is −44.5° C.

[0311] The TGA shows a weight loss of 10% at 450° C.

EXAMPLE 1 (comparative)

[0312] Copolymer PVE/TFE.

[0313] In a polymerization reactor identical to that described in Example 9, 250 &mgr;l of perfluoropropionylperoxide at 3% by weight in CFCl2CF2Cl, 9.8 mmoles of PVE and 18 mmoles of tetrafluoroethylene, are in sequence introduced.

[0314] The procedure already described in the previous Example 9 is followed until thermostating at the temperature of 30° C. under magnetic stirring. The reaction time is of eight hours.

[0315] After distillation of the unreacted monomers and stripping under vacuum at 150° C. for 3 hours, 540 mg of polymer are recovered.

[0316] By the 19F-NMR analysis carried out on the polymer dissolved in C6F6 it is calculated that the PVE molar percentage in the polymer is 23%.

[0317] The IR analysis shows that in the polymer spectrum there are absorption bands in the carboxyl zone, whose intensity is 10 times higher than that obtained from a MOVE 1/TFE copolymer film prepared according to Example 9, and having the same thickness:

[0318] The DSC graph does not show any melting endothermic curve, wherefore the polymer is amorphous. The TGA shows a weight loss of 2% at 427° C. and of 10% at 463° C. The Tg, determined by DSC, is +15° C.

[0319] The polymer intrinsic viscosity, measured at 30° C. in Fluorinert® FC-75, is 51 ml/g.

EXAMPLE 2 (comparative)

[0320] Copolymer between &bgr;-PDE (CF3OCF2CF2OCF═CF2)/TFE.

[0321] In a polymerization reactor identical to that described in Example 9, 250 &mgr;l of perfluoropropionylperoxide at 3% by weight in CFCl2—CF2Cl 10 mmoles of &bgr;-PDE and 18 mmoles of tetrafluoroethylene, are in sequence introduced.

[0322] The procedure described in the previous Example 9 is followed until the thermostating step at the temperature of 30° C. under magnetic stirring.

[0323] By the 19F-NMR analysis carried out on the polymer purified from the monomers by the processes described in the previous Examples, it is calculated that the molar percentage of &bgr;-PDE in the polymer is 23%.

[0324] The DSC graph does not show any melting endothermic curve wherefore the polymer is amorphous. The Tg, determined by DSC, is −4.8° C. This Tg value is clearly higher than those obtainable with the vinyl ethers of the invention (see above).

Claims

1. A fluoroelastomer comprising units derived from fluorovinyl ethers of formula:

CFX═CXOCF2OR  (I)

wherein:

1) R is a C2-C6 linear or branched perfluoroalkyl group, a C5-C6 cyclic perfluoroalkyl group, or a linear or branched perfluorooxyalkyl group comprising 2 to 6 carbon atoms and 1 to 3 oxygen atoms;

2) up to two fluorine atoms of the perfluoroalkyl group or the perfluorooxyalkyl group can be independently replaced with atoms selected from the group consisting of H, Cl, Br, and I; and

3) X is F or H.

2. The fluoroelastomer of

claim 1 wherein R is CF2CF2Y and Y is F or OCF3.

3. The fluoroelastomer of

claim 2 wherein each X is F.

4. The fluoroelastomer of

claim 3 wherein Y is F.

5. The fluoroelastomer of

claim 1 further comprising in the polymer chain units derived from either:

1) vinylidene fluoride and at least one additional copolymerizable comonomer selected from a C2-C8 perfluoroolefin; a C2-C8 chlorofluoroolefin; a C2-C8 bromofluoroolefin; a C2-C8 iodofluoroolefin; a fluoroalkyl vinyl ether of structure CF2═CFORtf, wherein Rtf is a C1-C6 alkyl group in which from one up to all hydrogen atoms are replaced with fluorine atoms; a perfluorooxyalkyl vinyl ether of structure CF2═CFOXt, wherein xt is a C1-C12 perfluorooxyalkyl group having one or more ether oxygens; or a C2-C8 olefin; or

2) tetrafluoroethylene and at least one additional copolymerizable comonomer selected from; fluoroalkyl vinyl ethers of structure CF2═CFORtf, wherein Rtf is as above defined; perfluorooxyalkyl vinyl ethers of structure CF2═CFOXt, wherein xt is as above defined;

C2-C8 fluoroolefin, chlorofluoroolefins, bromofluoroolefins, and iodofluoroolefins; and C2-C8 olefins.

6. The fluoroelastomer of

claim 5 wherein the C2-C8 perfluoroolefin is either tetrafluoroethylene, hexafluoropropene, or hexafluoroisobutene.

7. The fluoroelastomer of

claim 5 wherein the C2-C8 chlorofluoroolefin is chlorotrifluoroethylene.

8. The fluoroelastomer of

claim 5 wherein the C2-C8 bromofluoroolefin is bromotrifluoroethylene.

9. The fluoroelastomer of

claim 5 wherein the fluoroalkyl vinyl ether is heptafluoropropyl trifluorovinyl ether.

10. The fluoroelastomer of

claim 5 wherein the perfluorooxyalkyl vinyl ether is tetradecylfluoro-2-propoxypropyl trifluorovinyl ether.

11. The fluoroelastomer of

claim 5 wherein the C2-C8 olefin is either ethylene or propylene.

12. A fluoroelastomer made by the copolymerization of one or more comonomers, which comonomers together comprise a base fluoroelastomer composition, with a fluorovinyl ether of formula:

CFX═CXOCF2OR  (I)

wherein

1) R is a C2-C6 linear or branched perfluoroalkyl group, a C5-C6 cyclic perfluoroalkyl group, or a linear or branched perfluorooxyalkyl group comprising 2 to 6 carbon atoms and 1 to 3 oxygen atoms;

2) up to two fluorine atoms of the linear, branched or cyclic perfluoroalkyl group or the perfluorooxyalkyl group can be independently replaced with an atom selected from the group consisting of H, Cl, Br, and I; and

3) X is F or H; wherein

a sufficient amount of fluorovinyl ether is used in the copolymerization to result in an elastomeric copolymer.

13. The fluoroelastomer of

claim 12 wherein R is CF2CF2Y and Y is F or OCF3.

14. The fluoroelastomer of

claim 13 wherein each X is F.

15. The fluoroelastomer of

claim 14 wherein Y is F.

16. The fluoroelastomer of

claim 12 wherein the amount of fluorovinyl ether used in the copolymerization is at least about 10 mole %, the remainder comprising one or more comonomers.

17. The fluoroelastomer of

claim 16 wherein the amount of fluorovinyl ether used is at least about 15 mole %.

18. The fluoroelastomer of

claim 17 wherein the amount of fluorovinyl ether used is between about 15 mole % and about 20 mole %.

19. The fluoroelastomer of

claim 12 wherein the one or more comonomers are fluorinated compounds having at least one polymerizable carbon-carbon double bond, said comonomers being capable of forming copolymers with the fluorovinyl ether.

20. The fluoroelastomer of

claim 19 wherein the fluorinated compound further comprises at least one atom selected from the group consisting of chlorine, bromine, iodine, and oxygen.

21. The fluoroelastomer of

claim 19, wherein the olefin is copolymerized with at least one comonomer that is a C2-C8 olefin.

22. The fluoroelastomer of

claim 21 wherein the olefinically unsaturated hydrocarbon is selected from the group consisting of ethylene, propylene, and isobutylene.

23. The fluoroelastomer of

claim 19 wherein the one or more comonomers are selected from the following:

1) C2-C8 perfluoroolefins;

2) C2-C8 fluoroolefins;

3) C2-C8 chlorofluoroolefins,

4) C2-C8 bromofluoroolefins,

5) C2-C8 iodofluoroolefins;

6) perfluoroalkyl vinyl ethers having the structure CF2=CFOR f (PAVE), wherein R f is a Cl-C6 perfluoroalkyl group in which 0 or 1 of the fluorine atoms is replaced with a bromine atom;

7) fluorooxyalkyl vinyl ethers having the structure CF2═CFOXa, wherein Xa is a C1-C12 alkyl group, a C1-C12 oxyalkyl group, or a C1-C12 perfluorooxyalkyl group having at least one ether oxygen;

8) sulphonic monomers having the structure CF2═CFOXbSO2F, wherein Xb is selected from CF2CF2, CF2CF2CF2, and CF2CF(CFXC), and wherein Xc is selected from F, Cl, and Br;

9) a bis-olefin having the general formula RI1RI2C═CRI3,—Z—CRI4═CRI5RI6  (IA)

wherein;

RI1, RI2, RI3, RI4, RI5, and RI6, are the same or different and are either H or C1-C5 alkyl; and Z is a C1-C18 linear or branched alkylene or cycloalkylene diradical in which none to all of the hydrogen atoms are replaced with fluorine, or Z is a polyoxyalkylene diradical in which none to all of the hydrogen atoms are replaced with fluorine.

24. The fluoroelastomer of

claim 23 wherein the perfluoroolefin is selected from the group consisting of tetrafluoroethylene (TFE), hexafluoropropene (HFP), and hexafluoroisobutene.

25. The fluoroelastomer of

claim 23 wherein the fluoroolefin is selected from the group consisting of vinylfluoride (VF), vinylidene fluoride (VDF), trifluoroethylene, and fluoroalkenes represented by the formula CH2═CHR2f, wherein R2f is a linear or branched C1-C6 perfluoroalkyl group.

26. The fluoroelastomer of

claim 23 wherein the comonomer is either chlorotrifluoroethylene or bromotrifluoroethylene.

27. The fluoroelastomer of

claim 23 wherein Xa is the tetradecafluoro-2-propoxypropyl group.

28. The fluoroelastomer of

claim 23 wherein Z is at least partially fluorinated.

29. The fluoroelastomer of

claim 23 wherein Z is a perfluoropolyoxyalkylene diradical.

30. The fluoroelastomer of

claim 23 wherein Z is a C4-C12 perfluoroalkylene diradical and RI1, RI2, RI3, RI4, RI5, RI6 are H.

31. The fluoroelastomer of

claim 23 wherein Z is a fluoropolyoxyalkylene diradical having the formula:

—(Q)p—CF2O—(CF2CF2O)ma(CF2O)na—CF2—(Q)p—  (IIA)

wherein:

a) Q is a C1-C10 alkylene or oxyalkylene radical;

b) p is 0 or 1;

c) ma and na are integers such that the ma/na ratio is between about 0.2 and about 5; and

d) the molecular weight of the fluoropolyoxyalkylene diradical is between about 500 and about 10,000.

32. The fluoroelastomer of

claim 31 wherein the molecular weight of the fluoropolyoxyalkylene diradical is between about 1,000 and about 4,000.

33. The fluoroelastomer of

claim 31 wherein Q is selected from —CH2OCH2— and —CH2O(CH2CH2O)sCH2— wherein s is 1 to 3.

34. The fluoroelastomer of

claim 23 wherein the amount of bis-olefin of formula (IA) used in copolymerization is such that between about 0.001 and about 1 mole percent of repeat units in the polymer are dervied from the bis-olefin.

35. The fluoroelastomer of

claim 12 wherein the base fluoroelastomer composition is comprised of one or more comonomers selected from:

1) vinylidene fluoride and at least one additional comonomer selected from a C2-C8 perfluoroolefin; a C2-C8 chlorofluoroolefin; a C2-C8 bromofluoroolefin; a C2-C8 iodofluoroolefin; a fluoroalkyl vinyl ether of structure CF2═CFORtf, wherein Rtf is a C1-C6 alkyl group in which from one up to all hydrogen atoms replaced with fluorine and up to one such hydrogen atom not replaced with fluorine is replaced with bromine; perfluorooxyalkyl vinyl ethers of structure CF2═CFOXt, wherein xt is a C1-C12 perfluorooxyalkyl group having one or more ether oxygens; and a C2-C8 olefin; or

2) tetrafluoroethylene and at least one additional comonomer selected from a perfluoroalkylvinylether of structure CF2═CFORtf, wherein Rtf is as above defined; perfluorooxyalkylvinyl ethers of structure CF2═CFOXt, wherein xt is as above defined; a C2-C8 fluoroolefin, a C2-C8 chlorofluoroolefin, a C2-C8 bromofluoroolefins, or a C2-C8 iodofluoroolefin; and a C2-C8 olefin.

36. The fluoroelastomer of

claim 35 wherein the C2-C8 perfluoroolefin is selected from tetrafluoroethylene and hexafluoropropylene.

37. The fluoroelastomer of

claim 35 wherein the C2-C8 chlorofluoroolefin is chlorotrifluoroethylene.

38. The fluoroelastomer of

claim 35 wherein the C2-C8 bromofluoroolefin is bromotrifluoroethylene.

39. The fluoroelastomer of

claim 35 wherein the fluoroalkyl vinyl ether is pentafluoropropyl trifluorovinyl ether.

40. The fluoroelastomer of

claim 35 wherein the perfluorooxyalkyl vinyl ether is perfluoro-2-propoxypropyl vinyl ether.

41. The fluoroelastomer of

claim 35 wherein the C2-C8 olefin is either ethylene or propylene.

42. A fluoroelastomer, curable by a peroxidic route, comprising units derived from the following monomers:

1) from about 45 mole % to about 65 mole % vinylidene fluoride;

2) from 0 to about 45 mole % of either hexafluoropropene or a perfluoroalkyl vinyl ether of structure CF2═CFOR2f, wherein R2f is a C1-C6 perfluoroalkyl group in which 0 or 1 fluorine atoms are replaced with bromine atoms;

3) from 0 to about 30 mole % tetrafluoroethylene;

4) from 0 to about 40 mole % of a C2-C8 olefin; and

5) from 5 to about 40 mole % of a fluorovinyl ether of formula

CFX═CXOCF2OR  (I)

wherein:

a) R is a C2-C6 linear or branched perfluoroalkyl group, a C5-C6 cyclic perfluoroalkyl group, or a linear or branched perfluorooxyalkyl group comprising 2 to 6 carbon atoms and 1 to 3 oxygen atoms;

b) up to two fluorine atoms of the perfluoroalkyl group or the perfluorooxyalkyl group can be independently replaced with an atom selected from the group consisting of H, Cl, Br, and I; and

c) X is F or H; with the proviso that, together, less than about 45 mole % of all units in the fluoroelastomer are dervived from hexafluoropropene, perfluoroalky vinyl ether, and perfluorovinyl ether combined.

43. The fluoroelastomer of

claim 42 having one or more atoms selected from bromine and iodine.

44. The fluoroelastomer of

claim 42 in the form of an O-ring.

45. A fluoroelastomer, curable by a peroxidic route, comprising units derived from the following monomers:

1) from about 50 mole % to about 85 mole % tetrafluoroethylene;

2) from 0 to about 50 mole % of a perfluoroalkyl vinyl ether of structure CF2═CFOR2f, wherein R2f is a C1-C6 perfluoroalkyl group in which 0 or 1 fluorine atoms are replaced with bromine atoms;

4) from 0 to about 40 mole % of a C2-C8 olefin; and

5) from about 1 to about 40 mole % of a fluorovinyl ether of formula

CFX═CXOCF2OR

wherein:

a) R is a C2-C6 linear or branched perfluoroalkyl group, a C5-C6 cyclic perfluoroalkyl group, or a linear or branched perfluorooxyalkyl group comprising 2 to 6 carbon atoms and 1 to 3 oxygen atoms;

b) up to two fluorine atoms of the perfluoroalkyl group or the perfluorooxyalkyl group can be independently replaced with an atom selected from the group consisting of H, Cl, Br, and I; and

c) X is F or H; with the proviso that, together, less than about 50 mole % of the units are derived from perfluoroalky vinyl ether and fluorovinyl ether.

46. The fluoroelastomer of

claim 45 having one or more atoms that selected from bromine and iodine.

47. The fluoroelastomer of

claim 45 in the form of an 0-ring.

48. A fluoroelastomer, curable by an ionic route, comprising units derived from the following monomers in the given amounts:

1) between about 48 mole % and about 85 mole % vinylidene fluoride;

2) from 20 mole % up to about 35 mole % hexafluoropropene;

3) from 0 up to about 6 mole % of a perfluoroalkyl vinyl ether of structure CF2=CFOR2f, wherein R2f is a C1-C6 perfluoroalkyl group in which 0 or 1 fluorine atoms are replaced with bromine atoms;

3) from 0 up to about 20 mole % tetrafluoroethylene;

4) from about 3 mole % to about 9 mole % of a fluorovinyl ether of formula

CFX═CXOCF2OR

wherein:

a) R is a C2-C6 linear or branched perfluoroalkyl group, a C5-C6 cyclic perfluoroalkyl group, or a linear or branched perfluorooxyalkyl group comprising 2 to 6 carbon atoms and 1 to 3 oxygen atoms;

b) up to two fluorine atoms of the perfluoroalkyl group or the perfluorooxyalkyl group can be independently replaced with an atom selected from the group consisting of H, Cl, Br, and I; and

c) X is F or H; with the proviso that, together, less than about 10 mole % of the units are derived from perfluoroalkyl vinyl ether and perfluoorovinyl ether combined.

49. The fluoroelastomer of

claim 48 in the form of an O-ring.

50. A fluoroelastomer, curable by an ionic route, comprising units derived from the following monomers:

1) from about 30 mole % to about 47 mole % vinylidene fluoride;

2) from about 20 mole % to about 40 mole % hexafluoropropene;

3) from 0 up to about 17 mole % of a perfluoroalkyl vinyl ether of structure CF2═CFOR2f, wherein R2f is a C1-C6 perfluoroalkyl group in which 0 or 1 fluorine atoms are replaced with bromine atoms;

4) from about 10 mole % to about 30 mole % tetrafluoroethylene; and

5) from about 3 mole % to about 20 mole % of a fluorovinyl ether of formula

CFX═CXOCF2OR

wherein:

1) R is a C2-C6 linear or branched perfluoroalkyl group, a C5-C6 cyclic perfluoroalkyl group, or a linear or branched perfluorooxyalkyl group comprising 2 to 6 carbon atoms and 1 to 3 oxygen atoms;

2) up to two fluorine atoms of the perfluoroalkyl group or the perfluorooxyalkyl group can be independently replaced with an atom selected from the group consisting of H, Cl, Br, and I; and

3) X is F or H; with the proviso that, together, less than about 20 mole % of the units are derived from perfluoroalkyl vinyl ether and perfluorovinyl ether combined.

51. The fluoroelastomer of

claim 50 in the form of a hose.