Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F216/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an alcohol, ether, aldehydo, ketonic, acetal or ketal radical
  • C08F216/12—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an alcohol, ether, aldehydo, ketonic, acetal or ketal radical by an ether radical
  • C08F216/14—Monomers containing only one unsaturated aliphatic radical
  • C08F216/1416—Monomers containing oxygen in addition to the ether oxygen, e.g. allyl glycidyl ether

Definitions

• the present invention relates to fluorovinyl ethers, the process for preparing them and the polymers obtainable therefrom.
• perfluoroalkylvinyl ethers are generally used as monomers for the olefin copolymerization, specifically tetrafluoroethylene, vinylidene fluoride, chlorotrifluoroethylene (CTFE), hexafluoropropene.
• CTFE chlorotrifluoroethylene
• 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.
• a lower T g allows to have elastomeric polymers which can be used at lower temperatures and therefore to have available elastomers with a wider use range.
• 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.
• 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 T g is not reported.
• the general formula of the described vinyl ethers is the following:
• R o F 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.
• X 0 ⁇ F, Cl, CF 3 , 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.
• 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.
• U.S. Pat. No. 3,817,960 relates to the preparation and polymerization of perfluorovinyl ethers having the formula
• n′′ can range from 1 to 5.
• the compound synthesis is complex, it requires three steps.
• the preparation of the starting compound CF 3 O(CF 2 O) n′′ CF 2 C(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.
• U.S. Pat. No. 3,896,179 relates to the separation of “primary” isomers of perfluorovinylether, for example of CF 3 CF 2 CF 2 OCF ⁇ CF 2 from the corresponding less stable “secondary” isomers CF 3 (CF 3 )CFOCF ⁇ CF 2 .
• the latter are undesired products as regards both the polymer preparation and the poor properties of the obtained polymers.
• R o f is a C 1 -C 20 perfluoroalkyl optionally containing oxygen, X 1 ⁇ H, Cl, Br, F, COOR o , CONR o R wherein R o is a C 1 -C 10 alkyl group and R′ represents H or a C 1 -C 10 alkyl group.
• 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.
• U.S. Pat. No. 4,487,903 relates to the preparation of fluoroelastomeric copolymers using perfluorovinyl ethers having the formula:
• n 0 ranges from 1 to 4; Y o ⁇ F, Cl, CF 3 , H; X 2 can be C 1 -C 3 perfluoroalkyl group, C 1 -C 3 ⁇ -hydroperfluoroalkyl group, C 1 -C 3 ⁇ -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.
• EP 130,052 describes the perfluorovinylpolyether (PVPE) polymerization which leads to amorphous perfluoropolymers with a T g ranging from ⁇ 15 to ⁇ 100° C.
• the described polymers have T g values reaching up to ⁇ 76° C.; the further T g decrease is obtained by using perfluoropolyethers as plasticizers.
• PVPE perfluorovinylpolyether
• n′′′ ranges from 3 to 30 and R o f , is a perfluoroalkyl group.
• the used vinyl ethers are vinylether mixtures with different n′′′ values.
• n′′′ is equal to or higher than 3, preferably higher than 4.
• 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.
• U.S. Pat. No. 4,515,989 relates to the preparation of new intermediates for the fluorovinylether synthesis.
• the vinylether synthesis is improved by using an intermediate able to more easily decarboxylate.
• 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.
• PVPE perfluorovinylpolyethers
• 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.
• elemental fluorine is used, which is a highly oxidizing gas, with the consequent precautions connected to its use.
• the percentage of the comonomer in the polymer cannot exceed 50% by moles.
• U.S. Pat. No. 5,268,405 reports the preparation of perfluorinated rubbers having a low T g , by using high viscosity perfluoropolyethers as plasticizers of perfluorinated rubbers (TFE/MVE copolymers).
• TFE/MVE copolymers plasticizers of perfluorinated rubbers
• 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.
• U.S. Pat. No. 5,350,497 relates to the preparation of perfluoroalkylvinyl ethers by fluorination with elemental fluorine of hydrofluorochloroethers and subsequent dechlorination.
• 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).
• 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.
• 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.
• Perfluorooxyalkylvinyl ethers are furthermore used to confer to the fluorinated rubbers good properties at low temperatures, and specifically to lower the glass transition temperature.
• the T g 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.
• the amorphous copolymers of TFE with perfluoromethylvinylether have a T g 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).
• the T g extrapolated value of the MVE homopolymer is of about ⁇ 5° C. (J. Macromol. Sci.-Phys., B1(4), 815-830, Dec. 1967).
• 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.
• fluoroelastomers having better cold properties are those based on VDF, PAVE and optionally TFE units, curable by radical route with peroxides and crosslinking agents.
• VDF vinylidenfluoride
• 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.
• 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.
• Fluoroelastomers having an improved processability and very good mechanical and elastic properties curable both by ionic and peroxidic route, are also known.
• 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:
• 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:
• R is a C 2 -C 6 linear, branched or C 5 -C 6 cyclic (per)fluoroalkyl group, or a C 2 -C 6 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.
• the vinyl ethers according to the invention show the advantages reported hereinafter with respect to the known vinyl ethers.
• the T g lowering obtained with the vinyl ethers of the invention is connected to the presence of the (—OCF 2 O—) unit directly bound to the unsaturation.
• the T g lowering is surprisingly so evident to be defined a primary effect.
• the T g lowering, in copolymers with TFE having vinylether percentages of about 46% by weight is of 35° C. with respect to PVE
• the ⁇ -PDE vinylether does not give any advantage as regards T g .
• 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).
• PVE instead of fluorovinyl ethers
• 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.
• 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.
• T g The properties at low temperature (T g ) 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 —OCF 2 O— group directly bound to the unsaturation, as in the case of the CF 2 ⁇ CFOCF 2 CF 2 OCF 3 ( ⁇ -PDE)(see the Examples).
• a further advantage of the fluorovinyl ethers (I) of the invention 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: CF 2 (OF) 2 , CF 2 ⁇ CF 2 , CF 2 ⁇ CFOCF 3 , CHC1 ⁇ CFC1, CFC1 ⁇ CFC1, CF 2 ⁇ CFC1, CF 2 ⁇ CFH, CF 2 ⁇ CH 2 , CHC1 ⁇ CHC1 and other olefins.
• the copolymers of the invention are obtainable by polymerizing with suitable comonomers, the fluorovinyl ethers of general formula (I)-(IV).
• suitable comonomers the fluorovinyl ethers of general formula (I)-(IV).
• 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.
• 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.
• copolymer a polymer containing the vinyl ether of the invention and one or more comonomers, is meant.
• 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.
• fluorovinyl ethers of the present invention are non fluorinated C 2 -C 8 olefins, i.e. olefinically unsulated hydrocarbons such as ethylene, propylene, and isobutylene.
• C 2 -C 8 perfluoroolefins such as tetrafluoroethylene (TFE) hexafluoropropene (HFP), hexafluoroisobutene;
• C 2 -C 8 hydrogenated fluoroolefins such as vinyl fluoride (VF), vinylidene fluoride (VDF), trifluoroethylene,
• C 2 -C 8 chloro- and/or bromo- and/or iodo-fluoroolefins such as chlorotrifluoroethylene (CTFE) and bromotri-fluoroethylene;
• CF 2 ⁇ CFOX a (per)fluoro-oxyalkylvinyl ethers, wherein X a is a C 1 -C 12 alkyl, or a C 1 -C 12 oxyalkyl, or a C 1 -C 12 (per)fluorooxyalkyl having one or more ether groups, for example perfluoro-2-propoxy-propyl.
• sulphonic monomers having the structure CF 2 ⁇ CFOX b SO 2 F, wherein X b ⁇ CF 2 CF 2 , CF 2 CF 2 CF 2 , CF 2 CF(CFX C ) wherein X c ⁇ F, Cl, Br.
• R I 1 , R I 2 , R I 3 , R I 4 , R I 5 , R I 6 are H or C 1 -C 5 alkyls;
• Z is a C 1 -C 18 linear or branched alkylene or cycloalkylene radical, optionally containing oxygen atoms, preferably
• Z is preferably a C 4 -C 12 perfluoro-alkylene radical, while R I 1 , R I 2 , R I 3 , R I 4 , R I 5 , R I 6 are preferably hydrogen.
• Z is a (per) fluoropolyoxyalkylene radical, it preferably has the formula:
• Q is a C 1 -C 10 alkylene or oxyalkylene radical
• p is 0 or 1;
• 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.
• Q is selected from the following groups:
• 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.
• the amount of units in the chain deriving from said bis-olefins is generally in the range 0.01-1.0 by moles.
• the base structure of the fluoroelastomer can in particular be selected from:
• copolymers based on VDF wherein the latter is copolymerized with at least one copolymerizable comonomer selected from:
• C 2 -C 8 perfluoroolefins such as tetrafluoroethylene (TFE), hexafluoropropene (HFP) C 2 -C 8 chloro- and/or bromo and/or iodo-fluoroolefins, such as chlorotrifluoroethyethylene (CTFE) and bromotrifluoroethylene; CF 2 ⁇ CFOR t f (per)fluoroalkylvinyl ethers (PAVE), wherein R t f is a C 1 -C 6 (per)fluoroalkyl, for example trifluoromethyl, bromodifluoromethyl, pentafluoropropyl; CF 2 ⁇ CFOX t perfluorooxyalkylvinyl ethers, wherein X t is a C 1 -C 12 perfluorooxyalkyl having one or more ether groups, for example perfluoro-2-propoxy-
• preferred base monomeric compositions are the following: 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
• the fluoroelastomers of the invention are preferably cured by peroxidic route.
• the preferred compositions are the following when the fluoroelastomer is used for the O-Ring preparation: VDF 48-65 HFP 20-35 PAVE 0-6 TFE 0-20 MOVE 3-9
• fluoroelastomers containing reactive sites i.e. iodine and/or bromine in chain, preferably iodine (cure site monomer).
• an iodinated and/or brominated transfer agent can be used.
• 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.
• 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.
• radical initiators for example alkaline or ammonium persulphates, perphosphates, perborates or percarbonates
• ferrous, cuprous or silver salts or of other easily oxidizable metals.
• surfactants of various type are usually present, among which the fluorinated surfactants of formula:
• R 3 f is a C 5 -C 16 (per)fluoroalkyl chain or a (per) fluoropolyoxyalkyl chain
• X ⁇ is —COO ⁇ or —SO 3 ⁇
• M + is selected from: H + , NH 4 + , an alkaline metal ion.
• ammonium perfluorooctanoate, (per)fluoropolyoxyalkylenes ended with one or more carboxylic groups, etc. can be mentioned.
• the fluoroelastomer is separated from the emulsion by conventional methods, such as coagulation by addition of electrolytes or by cooling.
• 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.
• the polymerization reaction is generally carried out at temperatures comprised between 25° C. and 150° C., under pressure up to 10 MPa.
• 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.
• 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.
• 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 R b f (I) x (Br) y , wherein R b f 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).
• chain transfer agents iodides and/or bromides of alkaline or alkaline-earth metals according to U.S. Pat. No. 5,173,553.
• chain transfer agents containing iodine and/or bromine can be used.
• chain transfer agents containing iodine and/or bromine such as ethyl acetate, diethylmalonate, etc.
• Curing by peroxidic route is carried out, according to known techniques, by addition of a suitable peroxide able to generate radicals by heating.
• 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.
• 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.
• (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;
• N,N,N′,N′-tetraallyl-malonamide; tri-vinyl-isocyanurate; and 4,6-tri-vinyl-methyltrisiloxane, etc. are commonly used: TAIC is particularly preferred;
• 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;
• 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).
• 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.
• 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.
• 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.
• R 1 , R4, equal or different are H, F;
• R 2 , R 3 , equal or different are H, Cl under the following conditions: (1) when the final reaction is a dehalogenation R 2 , R 3 ⁇ Cl, (2) when the final reaction is a dehydrohalogenation one of the two substituents R 2 , R 3 is H and the other is Cl;
• R 5 , R 6 , R 7 , R 8 are:
• F or one of them is a C 1 -C 4 linear or branched perfluoroalkyl group, or a C 1 -C 4 linear or branched perfluorooxyalkyl group containing from one to three oxygen atoms, or R 5 and R 7 , or R 6 and R 8 , are linked each other to form with C 2 and C 1 a C 5 -C 6 cycle perfluoroalkyl group;
• R 5 -R 8 when one of the R 5 -R 8 , radicals is a C 2 -C 4 linear or branched fluoroalkyl, or a C 2 -C 4 linear or branched fluorooxyalkyl containing from one to three oxygen atoms, one or two of the other R 5 -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 R 5 and R 7 , or R 6 and R 8 , are linked each other to form with C 2 and C 1 a C 5 -C 6 cycle fluoroalkyl group, one of the two free substituents R 6 , R 8 or R 5 , R 7 is F and the other is selected from H, Cl, Br, Iodine.
• 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 R 1 -R 4 group, and respectively of the R 5 -R 8 group, are interchangeable each other, with the proviso that the position of each radical of each of the two groups R 1 -R 4 and R 5 -R 8 with respect to —OCF 2 O— 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.
• a hypofluorite gas flow CF 2 (OF) 2 comes into contact, in a suitable reactor with outlet, on the bottom of the same (first reactor), with a flow formed by the R 1 R 2 C ⁇ CR 3 R 4 olefin, optionally diluted in an inert fluid, so as to allow the chemical reaction a) with formation of the intermediate hypofluorite (VI).
• the reactants must be introduced into the reactor in an approximately unitary molar ratio, or with an excess of CF 2 (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.
• the reaction temperature can range from ⁇ 40° to ⁇ 150° C., preferably from ⁇ 80° to ⁇ 130° C.
• 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).
• the mixture of the products coming out from the first reactor can be heated at room temperature before being fed into the second reactor.
• 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.
• the solvents used in steps a) and b) are perfluorinated or chlorohydrofluorinated solvents or hydrofluorocarbons. Examples of said solvents are: CF 2 Cl 2 , CFCl 3 , CF 3 CF 2 H, CF 3 CFH 2 , CF 3 CF 2 CF 3 , CF 3 CCl 2 H, CF 3 CF 2 Cl.
• 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 R 1 to R 8 in the two olefins used in the synthesis allows to obtain the vinyl ethers of the present invention.
• Another object of the invention is a process wherein a hypofluorite of formula X 1 X 2 C(OF) 2 wherein X 1 and X 2 equal or different are F, CF 3 , and two fluoroalkenes of formula respectively R A 1 R A 2 C ⁇ CR A 3 R A 4 and R A 5 R A 6 C ⁇ CR A 7 R A 8 wherein R A 1 R A 8 equal or different, are F, H, Cl, Br, I, —CF 2 OSO 2 F, —SO 2 F,—COF, C 1 -C 5 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)
• thermogravimetric analysis TGA is carried out by using a 10° C./min rate.
• 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.
• 1.1 1/h (litres/hour) of CF 2 (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 CF 2 ⁇ CF 2 and 0.7 1/h of He is maintained through the second inlet pipe. Feeding is continued for 6.6 hours.
• 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.
• 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.
• reaction raw material is distilled by a plate column at atmospheric pressure, collecting 41.5 g of the desired product (boiling point 91° C.).
• 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.
• 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 CF 2 (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.
• Product B 69 (96); 97 (50); 135 (42); 151 (92); 185 (100).
• 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.
• 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 CF 2 (OF) 2 is 33%.
• the isomers have been separated by preparative gaschromatography.
• 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).
• the dehalogenation yield is 85%.
• 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%).
• Boiling range of the isomer mixture at atmospheric pressure 72.5 0 -74.5° C.
• 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);
• 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).
• Mass spectrum (electronic impact), main peaks and respective intensities): 69 (82); 119 (100); 185 (29); 246 (25); 251 (20); 312 (43).
• 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 ⁇ l of perfluoropropionylperoxide at 3% by weight in CFC1 2 CF 2 Cl 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.
• 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.
• reaction raw material which is finally recovered appears as a slightly viscous, transparent, colourless and homogeneous solution.
• the DSC graph does not show any melting endothermic curve, wherefore the polymer is amorphous.
• the polymer T g 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.
• 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.
• the 19 F-NMR analysis is in accordance with the copolymer structure having an average molecular weight of 35,000 and a MOVE 2/MOVE 2 a content equal to the percentages of the reacting mixture; unreacted monomers are not evident.
• 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.
• the reactor is cooled to the temperature of ⁇ 196° C., evacuated, then brought to room temperature and cooled again, the all twice.
• the reactor 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).
• 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.
• the DSC graph does not show any melting endothermic curve, wherefore the polymer is amorphous.
• the T g determined by DSC is ⁇ 21.4° C.
• 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).
• the polymer intrinsic viscosity measured at 30° C. in Fluorinert® FC-75, is 35.5 ml/g.
• the DSC graph does not show any melting endothermic curve, wherefore the polymer is amorphous.
• the T g determined by DSC is ⁇ 29.8° C.
• the TGA shows a weight loss of 10% at 435° C.
• the DSC graph does not show any melting endothermic curve, wherefore the polymer is amorphous.
• the T g determined by DSC, is ⁇ 47° C.
• the TGA shows a weight loss of 2% at 428° C. and of 10% at 455° C.
• 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.
• the DSC graph does not show any melting endothermic curve, wherefore the polymer is amorphous.
• the Tg determined by DSC, is ⁇ 37.5° C.
• the TGA shows a weight loss of 10% at 473° C.
• the polymer intrinsic viscosity measured at 30° C. in Fluorinert® FC-75, is 40.0 ml/g.
• the DSC graph does not show any melting endothermic curve, wherefore the polymer is amorphous.
• the T g determined by DSC, is ⁇ 44.5° C.
• the TGA shows a weight loss of 10% at 451° C.
• the polymer intrinsic viscosity measured at 30° C. in Fluorinert® FC-75, is 16.7 ml/g.
• the 19 F-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 T g . determined by DSC, is —58.0° C.
• the thermogravimetric analysis (TGA) shows a weight loss of 10% at 307° C.
• the reactor 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).
• the DSC graph does not show any melting endothermic curve wherefore the polymer is amorphous.
• the Tg determined by DSC, is ⁇ 44.5° C.
• the TGA shows a weight loss of 10% at 450° C.
• 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.
• the polymer intrinsic viscosity measured at 30° C. in Fluorinert® FC-75, is 51 ml/g.
• the DSC graph does not show any melting endothermic curve wherefore the polymer is amorphous.
• the T g 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).

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