CA2206092A1 - Fluorine-containing polymers and preparation thereof - Google Patents
Fluorine-containing polymers and preparation thereofInfo
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- CA2206092A1 CA2206092A1 CA 2206092 CA2206092A CA2206092A1 CA 2206092 A1 CA2206092 A1 CA 2206092A1 CA 2206092 CA2206092 CA 2206092 CA 2206092 A CA2206092 A CA 2206092A CA 2206092 A1 CA2206092 A1 CA 2206092A1
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Abstract
A method for polymerizing fluorine-containing ethylenically-unsaturated monomer and allylic-hydrogen containing olefin monomer is provided. The method involves the use of fluoroaliphatic-group containing sulfinate. Novel polymers are also disclosed, comprising interpolymerized units derived from tetrafluoroethylene and allylic-hydrogen containing olefin, for example, propylene.
Description
CA 02206092 1997-0~-27 W O 96/1866~ PCTAUS95/14260 Ei'LUORINE-CONTAINING POLYMERS AND PREPAR~TION 'l~REOF
This invention relates to fluorine-co~ ;..;--g polymers, their p[el~al~ion and use. In another aspect, this invention relates to methods of free-radical 10 polymerization of monomer mixtures comprising a fluorine-co~ it~ ethylenically-ull~ul~ed monomer and an allylic-hydrogen co..l~i..i..g olefin monomer, and to the rçs--ltin~ polyrners and shaped articles thereo~
Fluorine-co-.l~ il-g polymers, or fluoropolymers, are an important class of polymers and include for example, amorphous fluorocarbon elastomers and semi-1~ crystalline fluorocarbon plastics. Within this class are polymers of high thermal stability and usçfi~lness at high temperatures, and extreme toughnec.~ and flexibility at very low tempel ~Lul es. Many of these polymers are almost totally insoluble in a wide variety of organic solvents, and are chemically inert. Some have extremely low dielectric loss and high dielectric-strength, and most have unique nonadhesive and low-friction properties. See, for example, F.W. Billmeyer, Textbook of Polymer Science, 3rd ed., pp. 398-403, John Wiley & Sons, New York (1984).
Amorphous fluorocarbon elastomers, particularly the copolymers of vinylidene fluoride with other ethylenically unsaturated halogenated monomers, such as h~.Y~fl~olul)ropene, have particular utility in high temperature applications, such as seals, g~kets7 and linings - see, for example, Brullo, R.A., "Fluoroelastomer Rubber for Automotive Applications," Automotive Elastomer & Desi~n, June 1985, "Fluoroelastomer Seal Up Automotive Future," Materials En~ineerin~ October 1988, and "Fluorinated Elastomers," Kirk-Othmer, Encvclopedia of Chemical Technolo~y Vol. 8, pp. 500-515 (3rd ed., John Wiley & Sons, 1979).
Semi-crystalline fluoroplastics, particularly polychlorotrifluoroethylene, polytetrafluoroethylene, copolymers of tetrafluoroethylene and h~.Y~fll-oroplol)ylene, and poly(vinylidene fluoride), have numerous electrical,merh~nir.~l and chemical applications. Fluoroplastics are useful, for example, in wire coatings, electrical components, seals, solid and lined pipes, and pyroelectric CA 02206092 1997-0~-27 W O96/1866~ PCTrUS95/14260 detectors. See, for example, "Organic Fluorine Compounds," Kirk-Othmer, Encyclopedia of Chemical Technolo~y. Vol. 11, pp. 20, 21, 32, 33, 40, 41, 48, 50, 52, 62, 70, 71, John Wiley & Sons, (1980).
Fluorine-co.~t~ ,g polymers can be prepared by free-radical initiated 5 polymerization of one or more fluorine-co-l~ ng ethylenically unsaturated monomers. Free radicals are typically formed by the decomposition of a free-radical initiator. Free-radical initiators may be decomposed by light, heat, high energy radiation, or as a result of oxidation-reduction reactions. When free radicals are generated in the presence of free-radical polymerizable ethylenically unsaturated 0 monomers, a chain reaction occurs producing polymer. The polymer can be prepare:d by polymerization of monomers in bulk, in solution, in emulsion, or insuspension. Fluoroelastomers and fluoroplastics are preferably prepared by aqueous emulsion or suspension polymerization because of the rapid and nearly complei:e conversion of monomers, easy removal of the heat of polymerization andready isolation of the polymer. Emulsion or suspension polymerization typically involves polymerizing monomers in an aqueous medium in the presence of an inorganic free-radical initiator system, and surfactant or suspending agent.
Copolymers of tetrafluoroethylene ("TFE") and propylene, and terpolymers of TFE, propylene, and vinylidene fluoride are known and useful polymers. See, 20 e.g., D. E. Hull et al., "New Elastomers are More Re.~ict~nt to Many Automotive Fluids," SAE Technical Paper Series, #890361, SAE Publications Division, Warrendale, Pa., (1989), D. E. Hull et al., "New Type Fluoroelastomers With Improved Chemical R~ci~t~nce to Automotive Oils and Lubricants," SAE Technical Paper Series. #900121, SAE Publications Division, Warrendale, Pa., (1989), 2s Grootaelt et al., "Elastomers, Synthetic Fluorocarbon Elastomers," Kirk-Othmer, Encyclopedia of Chemical Technolo~y, Fourth Ed., Vol. 8, pp. 990-1005, John Wiley & Sons, (1993), Grootaert et al., "A Novel Fluorocarbon Elastomer For High-Temperature Sealing Applications In Aggressive Motor-Oil Environments,"
Rubber Chemistrv and Technolo~y. Volume 63, pp. 516-522, American Chemical 30 Society (l990), and Kolb et al., "Aging Behavior of Fluorocarbon in Various Motor Oils," Automotive Polymers & Desi~n, Volume 7 (No. 6), pp. 10-13, Lippincott &
This invention relates to fluorine-co~ ;..;--g polymers, their p[el~al~ion and use. In another aspect, this invention relates to methods of free-radical 10 polymerization of monomer mixtures comprising a fluorine-co~ it~ ethylenically-ull~ul~ed monomer and an allylic-hydrogen co..l~i..i..g olefin monomer, and to the rçs--ltin~ polyrners and shaped articles thereo~
Fluorine-co-.l~ il-g polymers, or fluoropolymers, are an important class of polymers and include for example, amorphous fluorocarbon elastomers and semi-1~ crystalline fluorocarbon plastics. Within this class are polymers of high thermal stability and usçfi~lness at high temperatures, and extreme toughnec.~ and flexibility at very low tempel ~Lul es. Many of these polymers are almost totally insoluble in a wide variety of organic solvents, and are chemically inert. Some have extremely low dielectric loss and high dielectric-strength, and most have unique nonadhesive and low-friction properties. See, for example, F.W. Billmeyer, Textbook of Polymer Science, 3rd ed., pp. 398-403, John Wiley & Sons, New York (1984).
Amorphous fluorocarbon elastomers, particularly the copolymers of vinylidene fluoride with other ethylenically unsaturated halogenated monomers, such as h~.Y~fl~olul)ropene, have particular utility in high temperature applications, such as seals, g~kets7 and linings - see, for example, Brullo, R.A., "Fluoroelastomer Rubber for Automotive Applications," Automotive Elastomer & Desi~n, June 1985, "Fluoroelastomer Seal Up Automotive Future," Materials En~ineerin~ October 1988, and "Fluorinated Elastomers," Kirk-Othmer, Encvclopedia of Chemical Technolo~y Vol. 8, pp. 500-515 (3rd ed., John Wiley & Sons, 1979).
Semi-crystalline fluoroplastics, particularly polychlorotrifluoroethylene, polytetrafluoroethylene, copolymers of tetrafluoroethylene and h~.Y~fll-oroplol)ylene, and poly(vinylidene fluoride), have numerous electrical,merh~nir.~l and chemical applications. Fluoroplastics are useful, for example, in wire coatings, electrical components, seals, solid and lined pipes, and pyroelectric CA 02206092 1997-0~-27 W O96/1866~ PCTrUS95/14260 detectors. See, for example, "Organic Fluorine Compounds," Kirk-Othmer, Encyclopedia of Chemical Technolo~y. Vol. 11, pp. 20, 21, 32, 33, 40, 41, 48, 50, 52, 62, 70, 71, John Wiley & Sons, (1980).
Fluorine-co.~t~ ,g polymers can be prepared by free-radical initiated 5 polymerization of one or more fluorine-co-l~ ng ethylenically unsaturated monomers. Free radicals are typically formed by the decomposition of a free-radical initiator. Free-radical initiators may be decomposed by light, heat, high energy radiation, or as a result of oxidation-reduction reactions. When free radicals are generated in the presence of free-radical polymerizable ethylenically unsaturated 0 monomers, a chain reaction occurs producing polymer. The polymer can be prepare:d by polymerization of monomers in bulk, in solution, in emulsion, or insuspension. Fluoroelastomers and fluoroplastics are preferably prepared by aqueous emulsion or suspension polymerization because of the rapid and nearly complei:e conversion of monomers, easy removal of the heat of polymerization andready isolation of the polymer. Emulsion or suspension polymerization typically involves polymerizing monomers in an aqueous medium in the presence of an inorganic free-radical initiator system, and surfactant or suspending agent.
Copolymers of tetrafluoroethylene ("TFE") and propylene, and terpolymers of TFE, propylene, and vinylidene fluoride are known and useful polymers. See, 20 e.g., D. E. Hull et al., "New Elastomers are More Re.~ict~nt to Many Automotive Fluids," SAE Technical Paper Series, #890361, SAE Publications Division, Warrendale, Pa., (1989), D. E. Hull et al., "New Type Fluoroelastomers With Improved Chemical R~ci~t~nce to Automotive Oils and Lubricants," SAE Technical Paper Series. #900121, SAE Publications Division, Warrendale, Pa., (1989), 2s Grootaelt et al., "Elastomers, Synthetic Fluorocarbon Elastomers," Kirk-Othmer, Encyclopedia of Chemical Technolo~y, Fourth Ed., Vol. 8, pp. 990-1005, John Wiley & Sons, (1993), Grootaert et al., "A Novel Fluorocarbon Elastomer For High-Temperature Sealing Applications In Aggressive Motor-Oil Environments,"
Rubber Chemistrv and Technolo~y. Volume 63, pp. 516-522, American Chemical 30 Society (l990), and Kolb et al., "Aging Behavior of Fluorocarbon in Various Motor Oils," Automotive Polymers & Desi~n, Volume 7 (No. 6), pp. 10-13, Lippincott &
-CA 02206092 1997-0~-27 W O 96/18665 PC~rUS9~14260 Peto, Inc. (1988). However, their m~nllf~ctllre has been known to be difficult, particularly with respect to the p, c;pal aLion of amorphous polymers derived ~om ; and propylene. Various patents describe processes to make these polymers.
U.S. Pat. No. 3,859,259 ~Iarrel et al.) plGpalt;s certain amorphous copolymers of 1 ~ ~ and propylene by a continuous aqueous emulsion polymerization process at high pressure (preferably about 500 to 1,500 psig) using arnmonium persulfate as initiator and sodium lauryl sulfate as the çm~ ifier.
U.S. Pat. No. 5,037,921 (Carlson) plepales certain fluoroelastomer copolymers of TF~ and propylene by a semi batch, emulsion polymerization processin the presence of diiodo chain L.ansrer agents. The polymerizations are preferably run at le,-,~ res of 70~C to 90~C and preferably at pressures of 2.6 to 2.7 MPa (380 to 400 psig).
U.S. Pat. No. 3,933,773 (Foerster) prepares certain thermoplastic elastomeric copolymers of 1~ and propylene by an emulsion poly}nerization reaction ~tili~inE a redox initiator system at a pressure of 100 to 1,000 psig, preferably 250 to 350 p.s.i.g.
It is generally believed that one important problem in these polymerizations is degradative chain ~. ~nsrel reactivity of alpha-olefins cot~ g an allylic hydrogen, e.g., propylene. See, e.g., Encyclopedia of Polymer Science and En~ineerin~ Volume 13, pp. 714-715, John Wiley & Sons (1988), and George Odian, Principles of Polymerization, 2nd Ed., pp. 250-251, John Wiley & Sons.
This degradative chain transfer is thought to be due to the weakness of the allylic carbon-hydrogen bond. For example, in propylene polymerizations, it is thought that a propylene molecule reacts with a prop~g~ting polymer-chain radical through transfer of its allylic hydrogen instead of through its double bond thus leading to low polymerization rates and resulting in polymers with low molecular weight. The formed allyl radical is resonance stabilized and unable to initiate a new polymerization.
CA 02206092 1997-0~-27 W 096/18665 PCT~US95/14260 + ~
H
This reaction is also believed to be temperature dependent, and the polymerization rate is expected to decrease at higher temperatures. Therefore a great deal of effort s has been put into development of low temperature redox initi~ting systems that would allow fast reaction rates and high molecular weight copolymers. Note that other monomers such as methyl methacrylate and methacrylonitrile, which also contain allylic carbon-hydrogen bonds, do not under go extensive degradative chain transfer because the ester or nitrile substituents are believed to stabilize the0 prop~tin~ radicals and decrease their reactivity toward transfer conlpa,ed to olefins.
U.S. Pat. No. 4,277,586 (Ukihashi et al.) discloses a method for the low temperature (0-50~C) polymerization of ~ and propylene. The patent states in Col. 1 t;hat "propylene-tetrafluoroethylene copolymers prepared by the conventional process~ss are characterized by low molecular weight. . . " In the method of the'586 pal:ent "When the reaction temperature is above 50~C, the molecular weight of ~he copolymer will be decreased and the Mooney viscosity of the copolymer will be increased." (Col. 3, line 68, and Col. 4, lines 1-3). See also, G. Kojima and M.~ eue, "Die Emulsionscopolymerisation von Tetrafluoroethylen mit Propylen bei 20 niedrigen Tempe-~u,en," Makromol. Chem., Vol. 182, pp. 1429-1439 (1981).
In U.S. 4,463,144 (Kojima et al. ) this process was improved by means of an initi~tin~ system comprising a water soluble persulfate, a water soluble iron salt, a hydrox~nneth~n~slllfin~te, and ethylenedi~minetetraacetic acid or a salt thereof, in an alkaline aqueous solution co.~;ni.~.~ a specific amount oftertialy butanol and an 25 emulsifier at pH of up to 10.5. The tertiary butanol is said to act as an accelerator and "If the amount of tertiary butanol is less than 5 wt.%, no adequate effects are obtainable."(Col. 4, lines 5-7).
U.S. Pat. No. 5,285,002 (Grootaert) discloses the p,cpa,~lion of fluorine-cont~ining polymers by polymerizing an aqueous emulsion or suspension of a 30 polymerizable mixture comprising fluoroaliphatic-group con~ g slllfin~te WO96/18665 ~CrlUS951~4260 Briefly, in one aspect, the present invention provides a method for the p~ lion of fluorine-cG.~ polymer comprising polymerizing, under free-radical conditions, an aqueous emulsion or ~u~ension of a polymerizable mixture comprising a fluorine-c~ E ethylenically-,msa~u1~Led monomer, an allylic-s hydrogen c~ olefin monomer, e.g., propylene, a fluoroaliph~tic-group coll~ g s--lfin~te~ and an o~ i7in~ agent capable of oxitli7i~ said sulfin~te to a sulfonyl radical.
In another aspect, this invention provides semi-crystalline copolymers comprising interpolymerized units derived from 1 ~ ~. and allylic-hydrogen 0 co..~ p olefin monomer, e.g., propylene, wherein less than 10%, pre~ bly less than 5%, of the total heat of fusion is attributable to a secondary melt-transition above 300~C as shown by the heating curve from Di~1enLial Sç~nning Calolilll~tly~DSC). The res-llting polymers possess improved processing con~pa1ed to prior art polymers, particularly at low processing temperatures.
We have found that with the use ofthe initi~ting system disclosed in U.S.
Patent No. 5,285,002, supra, both redox and thermal initiation is possible for monomer mixtures co~ fluorine-co~ monomers and allylic-hydrogen co111 ~ g monomers. Co1-1part:d to prior art processes, particularly in the plep~Lion of amorphous polymers, the process of the present invention does not 20 require cosolvents such as tertiary butanol, can be run smoothly at relatively low pressures, and proceeds at relatively rapid reaction rates. The polymers obtained are of usable molecular weight as indicated by their viscosity or melt-flow index (MFI) which are in the range of viscosities or MFI generally seen in cu11ll.1e1 ~,ially useful polymers, and are clean colorless polymers. Furthermore, there is no 2~ evidence ofthe degradative chain L1~11srt;1, even when polymerized at elevated temperatures such as 71~C, as evidenced by the absence of a detect~ble CF2H
resonance in the proton N~.
A class ofthe fluoroaliphatic slllfin~tes useful in this invention can be represented by the following general formulae CA 02206092 1997-0~-27 W O96/18665 PCTfUS9~/14260 R fS~2M 1 h, I
R ~'[SO2M ~
wherein Rf re~rc~s~nls a monovalent fluoro~liph~tic group having, for example, from 1 to 20 carbon atoms, preferably 4 to 10 carbon atoms, Rf represenls a polyvalent, preferably divalent, fluoroaliphatic group having, for example, from 1 to 20 carbon atoms, plerel~bly from 2 to 10 carbon atoms, M represents a hydrogen atom or s cation with valence x, which is 1 to 2, and is plere,dl~ly 1, n is 2 to 4, preferably 2.
The monovalent fluoroaliphatic group, Rf, is a fluorinated, stable, inert, non-polar"~alul~l~d moiety. It can be straight chain, branched chain, and, if suf~iciently large, cyclic, or col"bindlions thereof, such as alkyl cycloaliphatic groups.
Generally, Rf will have 1 to 20 carbon atoms, preferably 4 to 10, and will contain o 40 to 83 weight percent, preferably 50 to 78 weight percent fluorine. The pler~lled compounds are those in which the Rf group is fully or substantially completely fluorinated, as in the case where Rf is perfluoroalkyl, CnF2n+1, where n is 1 to 20.
The polyvalent, preferably divalent, fluoro~ h~tic group, Rf, is a fluo,i,laltd, stable, inert, non-polar, saturated moiety. It can be straight chain, 5 branched chain, and, if suffiiciently large, cyclic or co",bina~ions thereof, such as alkyl cycloaliphatic divalent groups. Generally, Rf, will have 1 to 20 carbon atoms, preferal~ly 2 to 10. Fx~mrles of p, ~fe, rc;d compounds are those in which the Rf group is perfluoroalkylene, CnF2n, where n is 1 to 20, or perfluorocycloalkyl, C~2" 2, where n is 5 to 20.
With respect to either R~ or Rf, the skeletal chain of carbon atoms can be interrupted by divalent oxygen, hexavalent sulfur or trivalent nitrogen hetero atoms, each of which is bonded only to carbon atoms, but preferably where such hetero atoms are present, such skeletal chain does not contain more than one said hetero atom for every two carbon atoms. An occasional carbon-bonded hydrogen atom, iodine, bromine, or chlorine atom may be present; where present, however, they pl ~re,~ly are present not more than one for every two carbon atoms in the chain.
Where Rf or Rf is or contains a cyclic structure, such structure preferably has 6 ring ~ , _ WO 9611~665 PCTJUS95J14260 m~ml~çr atoms, 1 or 2 of which can be said hetero atoms, e.g., oxygen and/or nitrogen. F.Y~ml~les of Rf groups are fluorinated allyl, e.g., C4Fg-, C6Fl3-, CgFI7-, alkoxyallyl, e.g., C3F7OCF2-. Examples of Rf' are fluorinated alkylene, e.g., -C4F8-, -C8FI6-. Where R~ is ~lesi~ted as a specific group, e.g., C8FI,-, it should be 5 understood that this group can re~ se~ll an average structure of a mixture, e.g., C6FI3- to CloF2l-~ which ~ ure can also include branched structures.
Repl~esel~lali~re fluoroaliphatic slllfin~te compounds use~l in the practice of this invention include the following:
CF3S02Na C4F9S~2H
C4FgSO2 Na C6F13S~2Na C8F17S~2Na CF3C(CI)2CF2s02K
Cl(CF2)gOC2F4S02Na Cl(CF2)xCF2SO2Na where x is 1 to 10 NaO2SCgFl6s02Na Nao2sc6Fl2so2Na NaO2SC2F4Oc2F4sO2Na NaO2SC2F4OC2F4X where X is Br or I
Nao2s(c4F8o)nc3F6so2Na where n is 1 to 20 NaO2SCF20(CF2CF20)m(CF20)nCF2S02Na where n and m are each 1 to 20 2s (CF3)2NCF2CF2SO2Na (c2F5)2NcF2cF2so2Na N(C2F4S02Na)3 NaO2SCgFl 6s02F
CA 02206092 1997-0~-27 W O96/18665 PCT~US95/14260 Nao2sc3F6o(c4F8o)nc3F6so2Na where n is 4 to 8 NaO2SCI~CF2--I~l\J~cF2cF2sc~2Na o/~CF2CFzSO~Na Suitable fluorine-co.. l~;n;.lg ethylenically-unsaturated monomers for use in this invention include the terminally unsaturated mono-olefins typically used for the p,c:p~ion of fluorine-cont~inin~ polymers such as vinylidene fluoride, hexafluol Opl ~,pelle, chlorotrifluoroethylene, 2-chloropentafluo, c,pl opene, perfluoroalkyl vinyl ethers, e.g., CF3OCF=CF2 or CF3CF2CF2OCF=CF2, 10 tetrafluoroethylene, l-I,~dropf~ n.1oroplopelle, 2-hydrop~nt~fluoroprol)ene, dichlorodifluoroethylene, trifluoroethylene, 1,1-dichlorofluoroethylene, vinyl fluoride, and mixtures thereo~ Perfluoro-1,3-dioxoles may also be used. The perfluoro-1,3-dioxole monomers and their copolymers are described, for example, in U.S. Pat. No. 4,558,141 (Squire). Certain fluorine-co-.1;~ di-olefins are also 5 useful, such as, perfluorodiallylether and perfluoro-1,3-butadiene.
A class of the allylic-hydrogen cont~ining olefin monomers useful in this invention are those mono-olefins which contain only carbon, hydrogen, and halogen atoms. Suitable allylic-hydrogen co..~ olefin monomers useful in the method ofthis invention include propylene, butylene, isobutylene, and 20 1,1,2-t~ifluo,uprop~ne.
The monomer mixtures useful in this invention may also contain additional ethylenically unsaturated comonomers, e.g., ethylene or butadiene. Said monomer mixtures may also contain iodine- or bromine-cont~ining cure-site comonomers in order to prepare peroxide curable polymers, e.g., fluoroelastomers. Suitable cure-25 site monomers include terminally unsaturated mono-olefins of 2 to 4 carbon atoms such as bromodifluoroethylene, bromotrifluoroethylene, iodotrifluoroethylene, CF2=CFOCF2CF2Br, and 4-bromo-3,3,4,4-tetrafluorobutene-1.
WO 96/18665 PCrrUS95~14~60 The method of this invention can comprise otherwise conventional emulsion or suspension free-radical polyme~ ion techniques. Such conv~ntinn~l emulsion or suspension poly.,l~:-~Lion techniques typically involve polymerizing monomersin an aqueous m~ m in the prt;sence of an inorganic free-radical initiator system s and surfactant or suspending agent. In one aspect, the method of this invention comprises the use of fluorinated slllfin~te as a re~lcing agent and a water soluble oxidi7in~ agent capable of converting the .s -lfin~te to a sulfonyl radical. ~lerelled oxitli7in~ agents are sodium, pot~.cium, and ammonium persl-lf~tec, perphosphates, ~elbol~les, and pel~;~bona~es. Particularly plerélled oxi-li7inE~ agents are sodium, 0 pot~ m, and a"-",ollium persulf~tes The sulfonyl radical so produced is believed to el;~ e SO2, forming a fluorinated radical that initi~tes the polym~ri7~tinn of the monomers.
In addition to the s~-lfin~te, other red~lcing agents can be present, such as sodium, potassium or ammonium sulfites, bisulfite, metabisulfite, hyposulfite, 15 thiosulfite, phosphite, sodium or potassium formaldehyde sulfoxylate or hypophosphite. Activators such as ferrous, cuprous, and silver salts, may also be present.
Aqueous emulsion and suspension polymerizations can be carried out under conventional steady-state conditions in which, for example, monomers, water, 20 surf~ct~nts, buffers and catalysts are fed continuously to a stirred reactor under opl;.,.u... pressure and temperature conditions while the res~llting emulsion or~uSIJellSiOn is removed contin--ou~ly. An alternative technique is batch or semibatch polymerization by feeding the ingredients into a stirred reactor and allowing them to react at a set te ~~per~L-Ire for a specified length of time or by charging ingredients 2s into the reactor and feeding the monomer into the reactor to "~ i.. a consL~lL
pressure until a desired amount of polymer is formed.
CA 02206092 1997-0~-27 W O96/18665 PCTrUS95114260 The amount of fluoro~liph~tic s -lfin~te used can vary, depending, for example, on the molecular weight of polymer desired. Preferably the amount of fluoro~liph~tic s-llfin~te is from 0.01 to 50 mole %, and most preferably from 0.05 to 10 mole %, of s~lfin~te compound based on total quantity of monomers.
Con,l~ alions of monos~llfin~tes, di~l-lfin~tçs, and tri~ ~lfin~tes can be used,depending on whether it is desired to use s llfin~te as an initiator, a monomer, or both. When polyvalent sulfin~tç~, such as those I epresented by Formula II, are used, the s--lfinQte is believed to act as a monomer and the fluorinated moiety is believed to be incol~ola~ed into the polymer backbone. When monosulfin~tes are o used the fluorinated moiety is believed to be incorporated as a polymer end group.
Polymers pl cp~ ed by the method of this invention, such as amorphous fluoroelastomers, can be compounded and cured using conventional methods. Such polymers are often cured by nucleophiles such as di~mines or polyhydroxy compounds. For example, certain fluoroelastomers prepal ed by the method of thisinvention may be cros~linl~ed with aromatic polyhydroxy compounds, such as bisphenols, which are compounded with the polymer along with a curing accelerator, such as a quaterna~y phosphonium salt, and acid acceptors, such as m~ n/~.~ium oxide and calcium hydroxide. Particularly useful polyhydroxy compounds include 4,4'-thiodiphenol, isopropylidene-bis(4-hydroxybenzene), and hexafluoroisopropylidene-bis(4-hydroxybenzene) ("bisphenol AF") which are described, for example, in U.S. Pat. No. 4,233,421 (Worm). Such crosslinkin~
methods are described, for example, in U.S. Pat. Nos. 4,287,320 (Kolb), 4,882,390 (Grootaert et al.), 5,086,123 (~u~ntllner et al.), and Canadian Patent 2056692 (Kruger et al.).
Certain polymers may be cured with peroxides. A cure-site monomer susceptible to free-radical attack is generally required to render polymers peroxide-curable. For c~",plc, polymers which contain interpolymerized units derived fromiodine- or brornine-co.,l~ ;..g monomers are often peroxide-curable. Such cure-site monomers are described, for example, in U.S. Pat. Nos 4,035,565 (Apotheker et al.), 4,450,263 (West), 4,564,662 (Albin), and C~n~ n Pat. Application No.
2,056,692 (Kruger et al.) Wo 96/18665 PCTIUS95114260 The semi-crystalline polymers of this invention co""~, ;se interpolymerized units derived from '1~1~ and an allylic-hydrogen co~ E olefin monomer. The semi-crystalline polymers of this invention differ from those of the prior art in that c they exhibit a much smaller, highLe~ )e~alu~e melt-peak. This is d~mnn~trated by s DSC curves which show that in the polymers ofthis invention less than 10%, pr~r~ably less than 5%, most pler~lably less than 3%, ofthe total heat offusion is attributable to a seconda.y melt-transition above 300~C. The semi-crystalline polymers of this invention possess improved processing co,.lpared to prior art polymers, particularly at low processing tempel~Lu-es, i.e., at or below 300~C.
lo Fillers can be mixed with the polymers of this invention to improve mol~ing characteristics and other prope, lies. When a filler is employed, it can be added in a...ou..l~ of up to about 100 parts per hundred parts by weight of polymer, preferably between about 15 to 50 parts per hundred parts by weight of the polymer. Fx~mrles of fillers which may be used are thermal-grade carbon blacks, 5 or fillers of relatively low ~c;i.~,-;e",ent characteristics such as clays and barytes.
The sl-lfin~te compounds useful in this invention result in polymers which have non-polar, non-ionic end groups. These non-ionic end groups generally result in improved plope lies such as improved thermal stability and improved rheological behavior. Polymers with non-ionic end groups exhibit lower apparenl viscosities 20 during procçsc~ing, e.g. injection molding, when con,pa. t:d at the same shear rates to polymers with ionic end groups. The res~llting polymers may be elastomers or plastics. The polymers may be shaped to form useful articles in~ -rling O rings,fuel-line hoses, shaft seals, and wire insulation.
2s EXAMPLES
In the following Fx~mples and ColllpdldLi~e Examples polymers were p-~ ed. The average reaction rates were observed and calculated in grams of total monomer con~llmP~l per liter of water (or water and cosolvent mixture) charged to the reactor per hour ("g/l-h").
CA 02206092 1997-0~-27 W O96/18665 PCTrUS95/14260 Mooney Viscosities of polyrners were measured at 121 ~C according to AST~ D 1646-81, using a Monsanto Mooney Viscome~el model MV 2000, a large rotor, 1 minute preheat, and measurement after 10 mimltes ("ML 1+10 ~ 121~C").
MFI for polyrners were obtained under the conditions described in the Fx~mrles and Col"~ ive Examples using the methodology described in ASTM
D-123 8 using a Tinius Olsen extrusion plastometer.
Therrnal analysis was pe,ro""ed using a TA Instruments DSC-2910 and 2000-series controller equipped with an LNCA-II controlled cooling accesso,y.
Heating curves were obtained under nitrogen purge by equilibrating samples at -100~C, holding isotherrnal for 1 minute, heating to 350~C at a heating rate of 10~C
per minute, slowly cooling back to -100~C under the "equilibrating segm~nt" of the eq~-iprn~nt software, and heating again to 350~C at a heating rate of 10~C per minute. ~e~tinp; curves shown in all of the Figures are from the second heating cycle.
Unless otherwise inflic~te~l, all % are by weight.
P~ Lion of s--lfin~tes Fluorochemical sl-lfin~tes can be prepared by deiodosl-lfin~tion ofthe corresponding iodides following the general procedure of Hu et al. in J. Or~.
Chem., Vol. 56, No. 8, 1991, page 2803. The fluorochemical s~1lfin~tes C4FgSO2Na and C6F13SO2Na were prepared by reduction ofthe corresponding sulfonyl fluorides C4FgSO2F and C6F13SO2F with Na2SO3 in a one to one mixture of water and dioxane. See also, U.S. Pat. No. 5,285,002, supra. The purity ofthese fluorochemical s~lfin~te~7 as determined by 19F NMR analysis, wasabout 90%.
W O96118665 PCTnUS95114~60 F,~ lple 1 A l9-liter reactor was cha,~ed with 13,500 g deionized water, 37.8 g KOH, 81 g ammonium perfluoro oct~no~te (commercially available from 3M Co. as 7 FLUORADlM FC 143 fluorochemical), 29.8 g Na2SO3, 324 g of a 20% solution of perfiuorohexyl sodium sl~lfin~t~- in water, and a solution of 0.56 g CuS04 5H20 in 500 mL deionized water. Af~ter r~ated vacuum/nitrogen purges, the reactor was heated under agitation (375 rpm) to 54~C and pressurized to 1.93 MPa (280 psig) with a mixture of 95% T~ ~ and 5% propylene. A 10% solution of ~..."-o~- ~m persulfate in dcio~ ed water was fed into the reactor through the use of a lo co~ . ;c pump at a rate of 1.2 grams per minute. As soon as the ples~ure dropped, intlic~tin~ polymerization, the monomers were repleni~hed at 1.86 MPa (270 psig), in a ratio of 75% '1~; and 25% propylene. The reaction proceeded for5 hours, during which 4,712 g monomer was con~med to give a calculated average reaction rate of 67 g/l-h. At this time the feed of ammonium persulfate solution was 15 halted, which stopped the reaction within 2 mimltes The excess monom~r was vented, and a white latex was drained from the reactor and the polymer was co~ ted by d,i~,pi"g into a solution of m~gne~ m chloride in water, followed by washing and drying, to yield a white rubbery polymer. The Mooney viscosity (ML 1+10~121~C) was 71.
Example 2 A l9-liter reactor was charged with 14,000 g deionized water, 50 g K2HPO4, 9 g KOX 81 g ~mmonillm perfluoro oct~noatç, and 324 g of a 20 %
solution of perfluorohexyl sodium sulfin~te in deionized water. After ,~ea~ed 25 vacuum/nitrogen purges, the reactor was heated to 71~C under ~git~ti~n ~445 rpm), and pressured to 2.07 MPa (300 psig) with a mixture of 50% T~ ~, 5% propylene, and 45% vinylidene fluoride. A 10% solution of ammonium persulfate in deionized water was fed into the reactor using a cons~all~etric pump at a rate of 3 grams per minute. As soon as the pressure dropped, the monomers were replenished with 30 55% TFE, 15% propylene, and 30% vinylidene fluoride. After 600 g ofthe ammonium persulfate solution was added, this feed was stopped and the reaction CA 02206092 1997-0~-27 W O96/18665 PCTrUS95/14260 allowed to contin~le In a total of 7 hours, 3,848 g of monomers were con~llmed to give a ç~lcul~te(l average reaction rate of 39 g/l-h. The reactor was cooled andexcess monomer was vented. A white latex was obtained and was worked up as in Example 1 to yield a rubbery polymer with a Mooney viscosity (ML 1+10~121~C) of28.
Example 3 A 150-liter enamel-lined reactor was charged with 105 kg deionized water, 2,024 g of a 20% solution of ~mmonium perfluoro oct~noate in deionized water, 0 284 g KOH, 223 g Na2SO3, 4.2 g CuS04 5H20, and 1,472 g of a 25% solution of perfluoro butyl sodium sl-lfin~te in deionized water. After repeated vacuum/nitrogen purges, the reactor contents were heated under agitation (210 rpm) to 54~C and the reactor was pressured with a mixture of 84.9% 1 12.1~/c vinylidene fluoride, and 3.0% propylene to a pressure of 1.59 MPa 1S (230 psig). A 10% solution of ammonium persulfate in deionized water was fed to the reactor at a rate of 400 g per hour and as soon as the pressu,e dropped, themonomer was replenished with a mixture of 71% 1 ~;, 22% propylene, and 7%
vinylidene fluoride as to ~--~;--l~in a constant pressure of 1.59 MPa (230 psig). After 5.75 hours, a total of 30 kg of monomer was con.~llmed to give a calculated average reaction rate of 50 gA-h. The initiator feed was stopped and the excess monomer was vented. The 22.7% solids latex was drained from the reactor and the polymer was co~ ted by dripping into a solution of m~gnesium chloride in water, followed by washing and drying, to yield a rubbery polymer. The Mooney viscosity~L 1 +10~121~C) was 90. The number average molecular weight (Mn) determined by N~ spectroscopy was 88,000.(0.17 mole % C4Fg endgroups).
Example 4 A 150-liter enamel-lined reactor was charged with 105 kg deionized water, 2,024 g of a 20% solution of ammonium perfluoro octanoate in deionized water, 68 g KOH, 376 g K2HP04, and 1,705 g of a 21% solution of perfluorobutyl sodium sulfin~l e in deionized water. After repeated vacuum/nitrogen purges the reactor wo 96tl8665 PCTrUS95l14260 co~ ls were heated under agitation (210 rpm) to 71 degrees centigrade and the reactor was ~c;s~uled to 1.59 MPa (230 psig) with 83.8% ~ ;, 3.2% propylene, and 13% vinylidene fluoride. A 10% solution of ammonium persulfate in water was fed to the reactor at a rate of 1.4 kg per hour, and as soon as the pressure dropped, s the monomers were replçniehed with 71% 1~, 22% propylene, and 7% vinylidene fluoride as to ..,~ consl~nl pressure of 1.59 MPa (230 psig). After 3.2 kg ofthe ammonium persulfate solution had been fed, this feed was halted and the reaction was continlle~ A~er 5. 8 hours, a total of 30 kg of monomer was con.~iu~..ed to give a c:~lclll~ted average reaction rate of 49 g/l-h. The reactor was cooled and excess monomer was vented. The 22.5% solids polymer latex was isolated and worked up as in Example 1. A white rubbery polymer was isolated with a Mooney viscosity (1\~ 1+10~121~C) of 65. The number average molecular weight ~,) determined by NMR spectroscopy was 91,000 (0.16 mole % C4Fg end-groups).
Example 5 A l9-liter reactor vessel was cha.ged with 14,000 g deionized water, 50 g K2HPO4 buffer, 9 g KOH, 81 g FC-143 ~m~ ifier, and 324 g of a 20% solution of perfluorohexyl sodium sulfin~te in water. Under agitation (445 rpm) the reactor was heated to 71~C and pressurized to 2.00 MPa (290 psig) with a mixture of 95% TFE and 5% propylene. Using a con.~t~metric pump, a 10% solution of anll,lo~ m persulfate in water was fed to the reactor at a rate of 135 g per hour.
When the pressure dropped, indicating reaction, the monomers were replenished ina Illi~Ul'e of 75% '~ and 25% propylene to ~ ;ll 2.00 ~a (290 psig). After 2s 389 g ofthe ammonium persulfate solution was added, this feed was stopped and the reaction continued thermally until a total of 4000 g of monomer was consumed.
This was achieved 4 hours and 45 minlltes after the reaction started to give a calculated average reaction rate of 60 g/l-h. At that time, the agitation was decreased and the reactor was cooled and vented. The reactor was drained and a highly transparent latex was obtained. The latex was co~ ted by dripping into a m~gnçsil1m chloride solution in water, to yield a snow-white elastomer gum which CA 02206092 1997-0~-27 W O96/18665 PCTrUS95/14260 was washed several times with hot deionized water and dried overnight at 110~C.
There was obtained a snow-white elastomer gum with a Mooney viscosity ~L 1+10 (~ 121~C) of 25.
5 Co~ u~Li~e Example C1 Polymer was prepared as in Example 5, but with omission of the perfluorohexyl sodium sl~lfin~te and all the ammonium persulfate was batch chal~ed at the beginning instead of pumping it in over time. The polymerization was extremely slow and the polymerization was abandoned after 3 hours. Only 368 g of10 monomer was con~l~med over this time to give a calculated average reaction rate of 9 g/l-h.
Co",p~ing F.~mples 1-5 with Colllpal~Live Example C1 illustrates the effect ofthe perfluoro alkyl s--lfin~te. In Examples 1-5, in which perfluoro alkyl 15 s llfin~te was used, the reaction proceeded rapidly. In Colllpal~Li~e Example C1, even with batch charging the persulfate, the rate was much slower than in Examples 1-5. Note that the rate in Colllpa~aLi~le Example C1 would have been even slower if the persulfate had been charged over time as in Examples 1-5, rather than batch chalged.
Example 6 A 19-liter vertically-stirred polymerization reactor was charged with 14,000 g deionized water, 9 g KOX 50 g K2HPO4, 81 g ammonium perfluoro oct~noate, and 162 g of a 20% solution of C6F,3SO2Na in deionized water. The 25 reactor was then al~ellla~ely evacuated and purged with N2 until ~2 level is less than 50 ppm. The reactor was then ev7~cll~te~17 the temperature raised to 71~C, and the agitation set at 445 rpm. Next, the reactor was charged with 455 g of l~ and 8.26 g of propylene to give a pressure of 1.52 MPa (220 psig). The polymerization was initi~ted by feeding a 5% solution of (NH4)2S208, in deionized water to the 30 reactor by means of a metering pump at approx;",~ely 4 g/min until 1 equivalent of (NH4)2S208 was fed (approxilllately 370 g of soln.). Upon the observation of a pressure drop, the running feed, which consisted of 93% TFE and 7% propylene, WO 96/18C65 PCTrUS9~/14260 was started and continuously adjusted by the reactor's control system in order to the desired pre~ure. The polyme-~ion was halted by slowing the agitation to 60 rpm after 3,784 g of TFE and 278 g of propylene had been fed, 4 hours after start of mnning feed to give a c~lcul~ted average reaction rate of73 g/l-h. The reactor was then vented, cooled, and drained to isolate the latex. The resulting polymer was isolated by freeze co~ tion~ washed six times with hot deionized water, and dried overnight in an oven at 100~C. The polymer, when analyzed by DSC, exhibited a broad melting tr~n.~ition with a peak melting tempe,a~re of 187~C and a small secondary melt-transition with a peak melting-te--.pe-~lule of 320~C which integration ofthe large and small melt-peaks shows accounts for 0.5% of the total heat of fusion (see Fig. 1). El~mPnt~l analysis of the polymer for carbon, hydrogen, and fluorine, indicated a polymer composition of 92.3% TFE and 7.7% propylene. The Melt Flow Index (~I) of the polymer was detellll,lled to be 13 g/10 min. ~ 265~C and 2.5 kg applied load.
Fx~ plc7 A 150-liter vertically-stirred polymerization reactor was charged with 120,000 g deionized water, 78 g KOH, 430 g K2HP04, 694 g ammonium perfluoro oct~no~tP:~ and 1,023 g of a 20% solution of C4FgSO2Na in deionized water. The reactor was then alternately ev~cu~ted and purged with N2 until O2 level is less than 50 ppm. The reactor was then ev~c~l~ted, the temperature raised to 71~C, and theagitation set at 210 rpm. Next, the reactor was charged with 3929 g of TFE and 79 g of propylene to give a pl e~u.e of 15.2 bar (220 psig). The polymerization was initi~ted by feeding a 5% solution of (N~)2S2Og in deionized water to the reactor by means of a metering pump at approxi. "~tely 25 g/min until 1 equivalent of (~H4)2S208 was fed (appl ~ ately 3,200 g of solution). Upon the observation of a pressure drop, the running feed, which consisted of 91% 'l ~ ~ and 9% propylene, was started and continuously adjusted by the reactor's control system in order to ~ the desired pressure. The polymerization was halted by slowing the agitation after 31,300 g of TFE and 3,080 g of propylene had been fed, 5 hours after start of running feed to give a calculated average reaction rate of CA 02206092 1997-0~-27 W O96/18665 PCTrUS95/14260 57 gA-h. The reactor was then vented, cooled, and drained to isolate the latex. The resulting polymer was co~ ted by adding HCI to the latex, gran~ ted, washed six times with d~ ecl water, and dried overnight in an oven at 120~C. The polymer, when analyzed by DSC, ~,A}.ibiled a broad melting transition with a peak melting tempc;, ~l~lre of 154~C and a small secondary melt-transition with a peak melting-telnpt. c-L~lre of 316~C which i,.leg. ~lion of the large and small melt-peaks shows accounts for 2.8% of the total heat of fusion (see Fig. 2). Elpm~nt~l analysis of the polymer for carbon, hydrogen, and fluorine, indicated a polymer composition of 90.9% 1~ ~ and 9.1% propylene. The Melt Flow Index (~I) of the polymer was determined to be 3.3 g/10 min. (~ 265~C and 2.16 kg applied load.
Example 8 An 86-liter vertically-stirred polymerization reactor was charged with 52,000 g deionized water, 140 g KOH, 300 g ammonium perfluoro oct~no~t~, 110 g Na2SO3, 2 g CuSO4-5H2O, and 1,000 g of a 20% solution of C6Fl3SO2Na in deioni~ed water. The reactor was then alternately ev~c~ted and purged with N2 until C~2 level is less than 50 ppm. The reactor was then evac~te(l, the te---pe-~ re raised to 54~C, and the agitation set at 150 rpm. Next, the reactor was charged with 1256 g of l~k; and 37.18 g of propylene to give a pressure of 0.83 MPa (120 psig). The poly.. e.iGalion was initi~ted by feeding a 10% solution of ~NH4)~S20g, in deionized water to the reactor by means of a metering pump at approximately 3 g/min until 778 g of soln. was fed. Upon the observation of a pressure drop, the running feed, which consisted of 88% 1~ and 12% propylene, was started and continuously adjusted by the reactor's control system in order to 25 ...~ the desired pressure. The polymerization was halted by slowing the agitation to 30 rpm after 7,825 g of TFE and 1080 g of propylene had been fed, 5 hours after start of running feed to give a calculated average reaction rate of 34 g/l--h. The reactor was then vented, cooled, and drained to isolate the latex. The rçs~ inp polymer was isolated by freeze coagulation, washed six times with hot 30 deionized water, and dried overnight in an oven at 100~C. The polymer, when analyzed by DSC, exhibited a broad melting transition with a peak melting W Og6/18665 PCTnUS9~114260 t~ el~Ult; of 103~C and no secondary melt-transition above 300~C (see Fig. 3).
Elemental analysis of the polymer for carbon, hydrogen, and fluorine, in :licated a polymer composition of 88.1% 1~ and 11.9% propylene. The Melt Flow Index (MFI) of the polymer was deLe. ~uned to be 7 g/l 0 min. ~ 1 90~C and 2.5 kg 5 applied load.
,. .
Co."pa,ali~re Example C2 A l9-liter vertically-stirred poly.,lel~alion reactor was chal~ed with 14,000 g deionized water, 9 g KOH, 50 g K2HOP4, and 81 g ammonium perfluoro 10 oct~n~te The reactor was then alle.n-d~ely ev~c l~ted and purged with N2 until O2 level is less than 50 ppm. The reactor was then evacu~terl~ the temperature raised to 71~C, and the agitation set at 445 rpm. Next, the reactor was cha-~;ed with 414 g of l~-~ and 11.2 g of propylene to give a pressure of 1.59 MPa (230 psig).The pol~lllt;-~Lon was initi~ted by feeding a 5% solution of(NH4)2S2O8 in 1S deionized water to the reactor by means of a metering pump a~p. o~.--ately 14 g/min until 1 equivalent of ~)2S2O8 was fed (approxiln~ y 370g of soln.).
No pressure drop, which would intlic~te the onset of polymerization, was observed.
Co.npa.~Li~re Fx~mrle C3 Following the procedure of example 6 of U.S. Pat. No. 3,933,733, supra, an 86-liter vertically-stirred polymerization reactor was charged with 60,000 g deionized water, 300 g NaOH, 300 g ammonium perfluoro octanoate, and 12 g Na2SO3. The reactor was then allel ,.dlely ev~cl~tecl and purged with N2 until O2 level is less than 50 ppm. The reactor was then evacuated, the temperature raised 25 to 60~C, and the agitation set at 150 rpm. Next, the reactor was charged with2100 g of'l~ and 46.~ g of propylene to give a pressure of 1.72 MPa (2~0 psig).
The polymerization was initi~te~ by feeding a 5.7% solution of ~I4)2S208 in deionized water to the reactor by means of a metering pump at maximum pump speed (approx;...~lçly 100 g/min) until 432 g of soln. was fed. Upon the 30 observation of a pressure drop, the running feed, which consisted of 88% 1~ and 12% propylene, was started and continuously adjusted by the reactor's control CA 02206092 1997-0~-27 system in order to ~ - the desired pressure. The polyl"e.i~Lion was halted after 6 hours by slowing the agitation to 50 rpm, during which time 3,458 g of TFE
and 489.5 g of propylene had been fed to give a c~lc~ ted average reaction rate of 11 gA-h. The reactor was then vented, cooled, and drained to isolate the 6% solids latex. The resl-lting polymer was i~ol~ted by freeze co~ tion~ washed six times with deionized water, and dried overnight in an oven at 100~C. The polymer, whenanalyzed by DSC, exhibited two melting transitions with peak melting temperatures of 105~C and 316~C (see fig. 4). Integration ofthe large and small melt-peaks shows that 26% of the total heat of fusion is attributable to the 316~C peak 0 (See Fig. 4). Fl~m~nt~l analysis of the polymer for carbon, hydrogen, and fluorine, indica~ed a polymer composition of 88.1% 1~ and 11.9% propylene. The Melt Flow l[ndex (~I) of the polymer was determined to be zero g/10 min ~ 265~C and 15 kg applied load.
Colll~al ~ e Example C4 Following the procedure described in U.S. Pat. No. 4,463,144, supra.
except using anl,llol~ium perfluoro oct~no~te as the emulsifier, an 86-liter vertically-stirred polymerization reactor was charged with 51,600 g deionized water, 5,600 g t-butanol, 281 g ammonium perfluoro octanoate, 167 g KOH, 857 g K2~04, 3.4 g Na2EDTA, and 2.8 g FeSO4-7H20. The reactor was then alternately evacu~ted and purged with N2 until O2 level is less than 50 ppm. The reactor was then ev~c~te~l, the tenlpel~L~lre raised to 27~C, and the agitation set at 130 rpm. Next, the reactor was charged with 2170 g of 1 ~ ~ and 64.1 g of propylene to g*e a pressure of 1.52 MPa ~220 psig). The polymerization was initi~ted by feeding a solution consisting of 175 g +Na~SO2CH20H, 15 g Na2EDTA, and 18.4 g KOH in 1810 g of deionized water, to the reactor by means of a metering pump (applox;.~-~tçly 3 g/min) until 950 g of soln. was fed. Upon the observation of a pressure drop, the running feed, which consisted of 88% 1~ and 12% propylene, was started and continuously adjusted by the reactor's control system in order to ,..~ the desired pressure.
The polymerization halted after 8,479 g of 1~ and 1,173 g of propylene had been fed, 5.5 hours after start of running feed to give a calculated average reaction rate of 30 g/l-h. The reactor was then vented, cooled, and drained to isolate the polymer suspension. The r~.cl-lting polymer was isolated by filtration, washed six times with hot deionized water, and dried overnight in an oven at 100~C. The polymer, when analyzed by DSC, e.~llibiLed two melting transitions with peak melting t~ elaL~lres of 114~C and 321~C (see Fig. ~). Integration ofthe large and small melt-peaks shows that 27% of the total heat of fusion is aUl;bulable to the 321~C peak (see Fig. 4). Ele-nPnf~1 analysis of the polymer for carbon, hydrogen, and fluorine, indicated a polymer composition of 88.8% TFE and 11.2% propylene.
The Melt Flow Index (MFI) ofthe polymer was determined to be 59 g/10 min (~
o 265~C and S kg applied load.
Examples 6-8 and Comparative Examples C2 and C3 show that unlike the semi-crystalline polymers of the prior art, the semi-crystalline polymers of this invention have very little if any melt transitions above 300~C. It is believed that the improved melt-processing of semi-crystalline polymers of this invention is due in part to the absence of significant melt-transitions above 300~C.
FT-IR spectra of thin films of the resultin~ polymers showed no observable carbonyl absorptions for Examples 6-9, a relatively large carbonyl absorption at1695 cm~l for Col~lp~live Example C2, and a moderate carbonyl absorption at 1744 cm-l for Comparative Example C3 . This indicates that the polymers of this invention do not contain significant amounts of carbonyl-cont~ining end-groups.
Various modifications and alterations of this invention will be apparent to those skilled in the art without departing from the scope and spirit of this invention and this invention should not be restricted to that set forth herein for illustrative purposes.
U.S. Pat. No. 3,859,259 ~Iarrel et al.) plGpalt;s certain amorphous copolymers of 1 ~ ~ and propylene by a continuous aqueous emulsion polymerization process at high pressure (preferably about 500 to 1,500 psig) using arnmonium persulfate as initiator and sodium lauryl sulfate as the çm~ ifier.
U.S. Pat. No. 5,037,921 (Carlson) plepales certain fluoroelastomer copolymers of TF~ and propylene by a semi batch, emulsion polymerization processin the presence of diiodo chain L.ansrer agents. The polymerizations are preferably run at le,-,~ res of 70~C to 90~C and preferably at pressures of 2.6 to 2.7 MPa (380 to 400 psig).
U.S. Pat. No. 3,933,773 (Foerster) prepares certain thermoplastic elastomeric copolymers of 1~ and propylene by an emulsion poly}nerization reaction ~tili~inE a redox initiator system at a pressure of 100 to 1,000 psig, preferably 250 to 350 p.s.i.g.
It is generally believed that one important problem in these polymerizations is degradative chain ~. ~nsrel reactivity of alpha-olefins cot~ g an allylic hydrogen, e.g., propylene. See, e.g., Encyclopedia of Polymer Science and En~ineerin~ Volume 13, pp. 714-715, John Wiley & Sons (1988), and George Odian, Principles of Polymerization, 2nd Ed., pp. 250-251, John Wiley & Sons.
This degradative chain transfer is thought to be due to the weakness of the allylic carbon-hydrogen bond. For example, in propylene polymerizations, it is thought that a propylene molecule reacts with a prop~g~ting polymer-chain radical through transfer of its allylic hydrogen instead of through its double bond thus leading to low polymerization rates and resulting in polymers with low molecular weight. The formed allyl radical is resonance stabilized and unable to initiate a new polymerization.
CA 02206092 1997-0~-27 W 096/18665 PCT~US95/14260 + ~
H
This reaction is also believed to be temperature dependent, and the polymerization rate is expected to decrease at higher temperatures. Therefore a great deal of effort s has been put into development of low temperature redox initi~ting systems that would allow fast reaction rates and high molecular weight copolymers. Note that other monomers such as methyl methacrylate and methacrylonitrile, which also contain allylic carbon-hydrogen bonds, do not under go extensive degradative chain transfer because the ester or nitrile substituents are believed to stabilize the0 prop~tin~ radicals and decrease their reactivity toward transfer conlpa,ed to olefins.
U.S. Pat. No. 4,277,586 (Ukihashi et al.) discloses a method for the low temperature (0-50~C) polymerization of ~ and propylene. The patent states in Col. 1 t;hat "propylene-tetrafluoroethylene copolymers prepared by the conventional process~ss are characterized by low molecular weight. . . " In the method of the'586 pal:ent "When the reaction temperature is above 50~C, the molecular weight of ~he copolymer will be decreased and the Mooney viscosity of the copolymer will be increased." (Col. 3, line 68, and Col. 4, lines 1-3). See also, G. Kojima and M.~ eue, "Die Emulsionscopolymerisation von Tetrafluoroethylen mit Propylen bei 20 niedrigen Tempe-~u,en," Makromol. Chem., Vol. 182, pp. 1429-1439 (1981).
In U.S. 4,463,144 (Kojima et al. ) this process was improved by means of an initi~tin~ system comprising a water soluble persulfate, a water soluble iron salt, a hydrox~nneth~n~slllfin~te, and ethylenedi~minetetraacetic acid or a salt thereof, in an alkaline aqueous solution co.~;ni.~.~ a specific amount oftertialy butanol and an 25 emulsifier at pH of up to 10.5. The tertiary butanol is said to act as an accelerator and "If the amount of tertiary butanol is less than 5 wt.%, no adequate effects are obtainable."(Col. 4, lines 5-7).
U.S. Pat. No. 5,285,002 (Grootaert) discloses the p,cpa,~lion of fluorine-cont~ining polymers by polymerizing an aqueous emulsion or suspension of a 30 polymerizable mixture comprising fluoroaliphatic-group con~ g slllfin~te WO96/18665 ~CrlUS951~4260 Briefly, in one aspect, the present invention provides a method for the p~ lion of fluorine-cG.~ polymer comprising polymerizing, under free-radical conditions, an aqueous emulsion or ~u~ension of a polymerizable mixture comprising a fluorine-c~ E ethylenically-,msa~u1~Led monomer, an allylic-s hydrogen c~ olefin monomer, e.g., propylene, a fluoroaliph~tic-group coll~ g s--lfin~te~ and an o~ i7in~ agent capable of oxitli7i~ said sulfin~te to a sulfonyl radical.
In another aspect, this invention provides semi-crystalline copolymers comprising interpolymerized units derived from 1 ~ ~. and allylic-hydrogen 0 co..~ p olefin monomer, e.g., propylene, wherein less than 10%, pre~ bly less than 5%, of the total heat of fusion is attributable to a secondary melt-transition above 300~C as shown by the heating curve from Di~1enLial Sç~nning Calolilll~tly~DSC). The res-llting polymers possess improved processing con~pa1ed to prior art polymers, particularly at low processing temperatures.
We have found that with the use ofthe initi~ting system disclosed in U.S.
Patent No. 5,285,002, supra, both redox and thermal initiation is possible for monomer mixtures co~ fluorine-co~ monomers and allylic-hydrogen co111 ~ g monomers. Co1-1part:d to prior art processes, particularly in the plep~Lion of amorphous polymers, the process of the present invention does not 20 require cosolvents such as tertiary butanol, can be run smoothly at relatively low pressures, and proceeds at relatively rapid reaction rates. The polymers obtained are of usable molecular weight as indicated by their viscosity or melt-flow index (MFI) which are in the range of viscosities or MFI generally seen in cu11ll.1e1 ~,ially useful polymers, and are clean colorless polymers. Furthermore, there is no 2~ evidence ofthe degradative chain L1~11srt;1, even when polymerized at elevated temperatures such as 71~C, as evidenced by the absence of a detect~ble CF2H
resonance in the proton N~.
A class ofthe fluoroaliphatic slllfin~tes useful in this invention can be represented by the following general formulae CA 02206092 1997-0~-27 W O96/18665 PCTfUS9~/14260 R fS~2M 1 h, I
R ~'[SO2M ~
wherein Rf re~rc~s~nls a monovalent fluoro~liph~tic group having, for example, from 1 to 20 carbon atoms, preferably 4 to 10 carbon atoms, Rf represenls a polyvalent, preferably divalent, fluoroaliphatic group having, for example, from 1 to 20 carbon atoms, plerel~bly from 2 to 10 carbon atoms, M represents a hydrogen atom or s cation with valence x, which is 1 to 2, and is plere,dl~ly 1, n is 2 to 4, preferably 2.
The monovalent fluoroaliphatic group, Rf, is a fluorinated, stable, inert, non-polar"~alul~l~d moiety. It can be straight chain, branched chain, and, if suf~iciently large, cyclic, or col"bindlions thereof, such as alkyl cycloaliphatic groups.
Generally, Rf will have 1 to 20 carbon atoms, preferably 4 to 10, and will contain o 40 to 83 weight percent, preferably 50 to 78 weight percent fluorine. The pler~lled compounds are those in which the Rf group is fully or substantially completely fluorinated, as in the case where Rf is perfluoroalkyl, CnF2n+1, where n is 1 to 20.
The polyvalent, preferably divalent, fluoro~ h~tic group, Rf, is a fluo,i,laltd, stable, inert, non-polar, saturated moiety. It can be straight chain, 5 branched chain, and, if suffiiciently large, cyclic or co",bina~ions thereof, such as alkyl cycloaliphatic divalent groups. Generally, Rf, will have 1 to 20 carbon atoms, preferal~ly 2 to 10. Fx~mrles of p, ~fe, rc;d compounds are those in which the Rf group is perfluoroalkylene, CnF2n, where n is 1 to 20, or perfluorocycloalkyl, C~2" 2, where n is 5 to 20.
With respect to either R~ or Rf, the skeletal chain of carbon atoms can be interrupted by divalent oxygen, hexavalent sulfur or trivalent nitrogen hetero atoms, each of which is bonded only to carbon atoms, but preferably where such hetero atoms are present, such skeletal chain does not contain more than one said hetero atom for every two carbon atoms. An occasional carbon-bonded hydrogen atom, iodine, bromine, or chlorine atom may be present; where present, however, they pl ~re,~ly are present not more than one for every two carbon atoms in the chain.
Where Rf or Rf is or contains a cyclic structure, such structure preferably has 6 ring ~ , _ WO 9611~665 PCTJUS95J14260 m~ml~çr atoms, 1 or 2 of which can be said hetero atoms, e.g., oxygen and/or nitrogen. F.Y~ml~les of Rf groups are fluorinated allyl, e.g., C4Fg-, C6Fl3-, CgFI7-, alkoxyallyl, e.g., C3F7OCF2-. Examples of Rf' are fluorinated alkylene, e.g., -C4F8-, -C8FI6-. Where R~ is ~lesi~ted as a specific group, e.g., C8FI,-, it should be 5 understood that this group can re~ se~ll an average structure of a mixture, e.g., C6FI3- to CloF2l-~ which ~ ure can also include branched structures.
Repl~esel~lali~re fluoroaliphatic slllfin~te compounds use~l in the practice of this invention include the following:
CF3S02Na C4F9S~2H
C4FgSO2 Na C6F13S~2Na C8F17S~2Na CF3C(CI)2CF2s02K
Cl(CF2)gOC2F4S02Na Cl(CF2)xCF2SO2Na where x is 1 to 10 NaO2SCgFl6s02Na Nao2sc6Fl2so2Na NaO2SC2F4Oc2F4sO2Na NaO2SC2F4OC2F4X where X is Br or I
Nao2s(c4F8o)nc3F6so2Na where n is 1 to 20 NaO2SCF20(CF2CF20)m(CF20)nCF2S02Na where n and m are each 1 to 20 2s (CF3)2NCF2CF2SO2Na (c2F5)2NcF2cF2so2Na N(C2F4S02Na)3 NaO2SCgFl 6s02F
CA 02206092 1997-0~-27 W O96/18665 PCT~US95/14260 Nao2sc3F6o(c4F8o)nc3F6so2Na where n is 4 to 8 NaO2SCI~CF2--I~l\J~cF2cF2sc~2Na o/~CF2CFzSO~Na Suitable fluorine-co.. l~;n;.lg ethylenically-unsaturated monomers for use in this invention include the terminally unsaturated mono-olefins typically used for the p,c:p~ion of fluorine-cont~inin~ polymers such as vinylidene fluoride, hexafluol Opl ~,pelle, chlorotrifluoroethylene, 2-chloropentafluo, c,pl opene, perfluoroalkyl vinyl ethers, e.g., CF3OCF=CF2 or CF3CF2CF2OCF=CF2, 10 tetrafluoroethylene, l-I,~dropf~ n.1oroplopelle, 2-hydrop~nt~fluoroprol)ene, dichlorodifluoroethylene, trifluoroethylene, 1,1-dichlorofluoroethylene, vinyl fluoride, and mixtures thereo~ Perfluoro-1,3-dioxoles may also be used. The perfluoro-1,3-dioxole monomers and their copolymers are described, for example, in U.S. Pat. No. 4,558,141 (Squire). Certain fluorine-co-.1;~ di-olefins are also 5 useful, such as, perfluorodiallylether and perfluoro-1,3-butadiene.
A class of the allylic-hydrogen cont~ining olefin monomers useful in this invention are those mono-olefins which contain only carbon, hydrogen, and halogen atoms. Suitable allylic-hydrogen co..~ olefin monomers useful in the method ofthis invention include propylene, butylene, isobutylene, and 20 1,1,2-t~ifluo,uprop~ne.
The monomer mixtures useful in this invention may also contain additional ethylenically unsaturated comonomers, e.g., ethylene or butadiene. Said monomer mixtures may also contain iodine- or bromine-cont~ining cure-site comonomers in order to prepare peroxide curable polymers, e.g., fluoroelastomers. Suitable cure-25 site monomers include terminally unsaturated mono-olefins of 2 to 4 carbon atoms such as bromodifluoroethylene, bromotrifluoroethylene, iodotrifluoroethylene, CF2=CFOCF2CF2Br, and 4-bromo-3,3,4,4-tetrafluorobutene-1.
WO 96/18665 PCrrUS95~14~60 The method of this invention can comprise otherwise conventional emulsion or suspension free-radical polyme~ ion techniques. Such conv~ntinn~l emulsion or suspension poly.,l~:-~Lion techniques typically involve polymerizing monomersin an aqueous m~ m in the prt;sence of an inorganic free-radical initiator system s and surfactant or suspending agent. In one aspect, the method of this invention comprises the use of fluorinated slllfin~te as a re~lcing agent and a water soluble oxidi7in~ agent capable of converting the .s -lfin~te to a sulfonyl radical. ~lerelled oxitli7in~ agents are sodium, pot~.cium, and ammonium persl-lf~tec, perphosphates, ~elbol~les, and pel~;~bona~es. Particularly plerélled oxi-li7inE~ agents are sodium, 0 pot~ m, and a"-",ollium persulf~tes The sulfonyl radical so produced is believed to el;~ e SO2, forming a fluorinated radical that initi~tes the polym~ri7~tinn of the monomers.
In addition to the s~-lfin~te, other red~lcing agents can be present, such as sodium, potassium or ammonium sulfites, bisulfite, metabisulfite, hyposulfite, 15 thiosulfite, phosphite, sodium or potassium formaldehyde sulfoxylate or hypophosphite. Activators such as ferrous, cuprous, and silver salts, may also be present.
Aqueous emulsion and suspension polymerizations can be carried out under conventional steady-state conditions in which, for example, monomers, water, 20 surf~ct~nts, buffers and catalysts are fed continuously to a stirred reactor under opl;.,.u... pressure and temperature conditions while the res~llting emulsion or~uSIJellSiOn is removed contin--ou~ly. An alternative technique is batch or semibatch polymerization by feeding the ingredients into a stirred reactor and allowing them to react at a set te ~~per~L-Ire for a specified length of time or by charging ingredients 2s into the reactor and feeding the monomer into the reactor to "~ i.. a consL~lL
pressure until a desired amount of polymer is formed.
CA 02206092 1997-0~-27 W O96/18665 PCTrUS95114260 The amount of fluoro~liph~tic s -lfin~te used can vary, depending, for example, on the molecular weight of polymer desired. Preferably the amount of fluoro~liph~tic s-llfin~te is from 0.01 to 50 mole %, and most preferably from 0.05 to 10 mole %, of s~lfin~te compound based on total quantity of monomers.
Con,l~ alions of monos~llfin~tes, di~l-lfin~tçs, and tri~ ~lfin~tes can be used,depending on whether it is desired to use s llfin~te as an initiator, a monomer, or both. When polyvalent sulfin~tç~, such as those I epresented by Formula II, are used, the s--lfinQte is believed to act as a monomer and the fluorinated moiety is believed to be incol~ola~ed into the polymer backbone. When monosulfin~tes are o used the fluorinated moiety is believed to be incorporated as a polymer end group.
Polymers pl cp~ ed by the method of this invention, such as amorphous fluoroelastomers, can be compounded and cured using conventional methods. Such polymers are often cured by nucleophiles such as di~mines or polyhydroxy compounds. For example, certain fluoroelastomers prepal ed by the method of thisinvention may be cros~linl~ed with aromatic polyhydroxy compounds, such as bisphenols, which are compounded with the polymer along with a curing accelerator, such as a quaterna~y phosphonium salt, and acid acceptors, such as m~ n/~.~ium oxide and calcium hydroxide. Particularly useful polyhydroxy compounds include 4,4'-thiodiphenol, isopropylidene-bis(4-hydroxybenzene), and hexafluoroisopropylidene-bis(4-hydroxybenzene) ("bisphenol AF") which are described, for example, in U.S. Pat. No. 4,233,421 (Worm). Such crosslinkin~
methods are described, for example, in U.S. Pat. Nos. 4,287,320 (Kolb), 4,882,390 (Grootaert et al.), 5,086,123 (~u~ntllner et al.), and Canadian Patent 2056692 (Kruger et al.).
Certain polymers may be cured with peroxides. A cure-site monomer susceptible to free-radical attack is generally required to render polymers peroxide-curable. For c~",plc, polymers which contain interpolymerized units derived fromiodine- or brornine-co.,l~ ;..g monomers are often peroxide-curable. Such cure-site monomers are described, for example, in U.S. Pat. Nos 4,035,565 (Apotheker et al.), 4,450,263 (West), 4,564,662 (Albin), and C~n~ n Pat. Application No.
2,056,692 (Kruger et al.) Wo 96/18665 PCTIUS95114260 The semi-crystalline polymers of this invention co""~, ;se interpolymerized units derived from '1~1~ and an allylic-hydrogen co~ E olefin monomer. The semi-crystalline polymers of this invention differ from those of the prior art in that c they exhibit a much smaller, highLe~ )e~alu~e melt-peak. This is d~mnn~trated by s DSC curves which show that in the polymers ofthis invention less than 10%, pr~r~ably less than 5%, most pler~lably less than 3%, ofthe total heat offusion is attributable to a seconda.y melt-transition above 300~C. The semi-crystalline polymers of this invention possess improved processing co,.lpared to prior art polymers, particularly at low processing tempel~Lu-es, i.e., at or below 300~C.
lo Fillers can be mixed with the polymers of this invention to improve mol~ing characteristics and other prope, lies. When a filler is employed, it can be added in a...ou..l~ of up to about 100 parts per hundred parts by weight of polymer, preferably between about 15 to 50 parts per hundred parts by weight of the polymer. Fx~mrles of fillers which may be used are thermal-grade carbon blacks, 5 or fillers of relatively low ~c;i.~,-;e",ent characteristics such as clays and barytes.
The sl-lfin~te compounds useful in this invention result in polymers which have non-polar, non-ionic end groups. These non-ionic end groups generally result in improved plope lies such as improved thermal stability and improved rheological behavior. Polymers with non-ionic end groups exhibit lower apparenl viscosities 20 during procçsc~ing, e.g. injection molding, when con,pa. t:d at the same shear rates to polymers with ionic end groups. The res~llting polymers may be elastomers or plastics. The polymers may be shaped to form useful articles in~ -rling O rings,fuel-line hoses, shaft seals, and wire insulation.
2s EXAMPLES
In the following Fx~mples and ColllpdldLi~e Examples polymers were p-~ ed. The average reaction rates were observed and calculated in grams of total monomer con~llmP~l per liter of water (or water and cosolvent mixture) charged to the reactor per hour ("g/l-h").
CA 02206092 1997-0~-27 W O96/18665 PCTrUS95/14260 Mooney Viscosities of polyrners were measured at 121 ~C according to AST~ D 1646-81, using a Monsanto Mooney Viscome~el model MV 2000, a large rotor, 1 minute preheat, and measurement after 10 mimltes ("ML 1+10 ~ 121~C").
MFI for polyrners were obtained under the conditions described in the Fx~mrles and Col"~ ive Examples using the methodology described in ASTM
D-123 8 using a Tinius Olsen extrusion plastometer.
Therrnal analysis was pe,ro""ed using a TA Instruments DSC-2910 and 2000-series controller equipped with an LNCA-II controlled cooling accesso,y.
Heating curves were obtained under nitrogen purge by equilibrating samples at -100~C, holding isotherrnal for 1 minute, heating to 350~C at a heating rate of 10~C
per minute, slowly cooling back to -100~C under the "equilibrating segm~nt" of the eq~-iprn~nt software, and heating again to 350~C at a heating rate of 10~C per minute. ~e~tinp; curves shown in all of the Figures are from the second heating cycle.
Unless otherwise inflic~te~l, all % are by weight.
P~ Lion of s--lfin~tes Fluorochemical sl-lfin~tes can be prepared by deiodosl-lfin~tion ofthe corresponding iodides following the general procedure of Hu et al. in J. Or~.
Chem., Vol. 56, No. 8, 1991, page 2803. The fluorochemical s~1lfin~tes C4FgSO2Na and C6F13SO2Na were prepared by reduction ofthe corresponding sulfonyl fluorides C4FgSO2F and C6F13SO2F with Na2SO3 in a one to one mixture of water and dioxane. See also, U.S. Pat. No. 5,285,002, supra. The purity ofthese fluorochemical s~lfin~te~7 as determined by 19F NMR analysis, wasabout 90%.
W O96118665 PCTnUS95114~60 F,~ lple 1 A l9-liter reactor was cha,~ed with 13,500 g deionized water, 37.8 g KOH, 81 g ammonium perfluoro oct~no~te (commercially available from 3M Co. as 7 FLUORADlM FC 143 fluorochemical), 29.8 g Na2SO3, 324 g of a 20% solution of perfiuorohexyl sodium sl~lfin~t~- in water, and a solution of 0.56 g CuS04 5H20 in 500 mL deionized water. Af~ter r~ated vacuum/nitrogen purges, the reactor was heated under agitation (375 rpm) to 54~C and pressurized to 1.93 MPa (280 psig) with a mixture of 95% T~ ~ and 5% propylene. A 10% solution of ~..."-o~- ~m persulfate in dcio~ ed water was fed into the reactor through the use of a lo co~ . ;c pump at a rate of 1.2 grams per minute. As soon as the ples~ure dropped, intlic~tin~ polymerization, the monomers were repleni~hed at 1.86 MPa (270 psig), in a ratio of 75% '1~; and 25% propylene. The reaction proceeded for5 hours, during which 4,712 g monomer was con~med to give a calculated average reaction rate of 67 g/l-h. At this time the feed of ammonium persulfate solution was 15 halted, which stopped the reaction within 2 mimltes The excess monom~r was vented, and a white latex was drained from the reactor and the polymer was co~ ted by d,i~,pi"g into a solution of m~gne~ m chloride in water, followed by washing and drying, to yield a white rubbery polymer. The Mooney viscosity (ML 1+10~121~C) was 71.
Example 2 A l9-liter reactor was charged with 14,000 g deionized water, 50 g K2HPO4, 9 g KOX 81 g ~mmonillm perfluoro oct~noatç, and 324 g of a 20 %
solution of perfluorohexyl sodium sulfin~te in deionized water. After ,~ea~ed 25 vacuum/nitrogen purges, the reactor was heated to 71~C under ~git~ti~n ~445 rpm), and pressured to 2.07 MPa (300 psig) with a mixture of 50% T~ ~, 5% propylene, and 45% vinylidene fluoride. A 10% solution of ammonium persulfate in deionized water was fed into the reactor using a cons~all~etric pump at a rate of 3 grams per minute. As soon as the pressure dropped, the monomers were replenished with 30 55% TFE, 15% propylene, and 30% vinylidene fluoride. After 600 g ofthe ammonium persulfate solution was added, this feed was stopped and the reaction CA 02206092 1997-0~-27 W O96/18665 PCTrUS95/14260 allowed to contin~le In a total of 7 hours, 3,848 g of monomers were con~llmed to give a ç~lcul~te(l average reaction rate of 39 g/l-h. The reactor was cooled andexcess monomer was vented. A white latex was obtained and was worked up as in Example 1 to yield a rubbery polymer with a Mooney viscosity (ML 1+10~121~C) of28.
Example 3 A 150-liter enamel-lined reactor was charged with 105 kg deionized water, 2,024 g of a 20% solution of ~mmonium perfluoro oct~noate in deionized water, 0 284 g KOH, 223 g Na2SO3, 4.2 g CuS04 5H20, and 1,472 g of a 25% solution of perfluoro butyl sodium sl-lfin~te in deionized water. After repeated vacuum/nitrogen purges, the reactor contents were heated under agitation (210 rpm) to 54~C and the reactor was pressured with a mixture of 84.9% 1 12.1~/c vinylidene fluoride, and 3.0% propylene to a pressure of 1.59 MPa 1S (230 psig). A 10% solution of ammonium persulfate in deionized water was fed to the reactor at a rate of 400 g per hour and as soon as the pressu,e dropped, themonomer was replenished with a mixture of 71% 1 ~;, 22% propylene, and 7%
vinylidene fluoride as to ~--~;--l~in a constant pressure of 1.59 MPa (230 psig). After 5.75 hours, a total of 30 kg of monomer was con.~llmed to give a calculated average reaction rate of 50 gA-h. The initiator feed was stopped and the excess monomer was vented. The 22.7% solids latex was drained from the reactor and the polymer was co~ ted by dripping into a solution of m~gnesium chloride in water, followed by washing and drying, to yield a rubbery polymer. The Mooney viscosity~L 1 +10~121~C) was 90. The number average molecular weight (Mn) determined by N~ spectroscopy was 88,000.(0.17 mole % C4Fg endgroups).
Example 4 A 150-liter enamel-lined reactor was charged with 105 kg deionized water, 2,024 g of a 20% solution of ammonium perfluoro octanoate in deionized water, 68 g KOH, 376 g K2HP04, and 1,705 g of a 21% solution of perfluorobutyl sodium sulfin~l e in deionized water. After repeated vacuum/nitrogen purges the reactor wo 96tl8665 PCTrUS95l14260 co~ ls were heated under agitation (210 rpm) to 71 degrees centigrade and the reactor was ~c;s~uled to 1.59 MPa (230 psig) with 83.8% ~ ;, 3.2% propylene, and 13% vinylidene fluoride. A 10% solution of ammonium persulfate in water was fed to the reactor at a rate of 1.4 kg per hour, and as soon as the pressure dropped, s the monomers were replçniehed with 71% 1~, 22% propylene, and 7% vinylidene fluoride as to ..,~ consl~nl pressure of 1.59 MPa (230 psig). After 3.2 kg ofthe ammonium persulfate solution had been fed, this feed was halted and the reaction was continlle~ A~er 5. 8 hours, a total of 30 kg of monomer was con.~iu~..ed to give a c:~lclll~ted average reaction rate of 49 g/l-h. The reactor was cooled and excess monomer was vented. The 22.5% solids polymer latex was isolated and worked up as in Example 1. A white rubbery polymer was isolated with a Mooney viscosity (1\~ 1+10~121~C) of 65. The number average molecular weight ~,) determined by NMR spectroscopy was 91,000 (0.16 mole % C4Fg end-groups).
Example 5 A l9-liter reactor vessel was cha.ged with 14,000 g deionized water, 50 g K2HPO4 buffer, 9 g KOH, 81 g FC-143 ~m~ ifier, and 324 g of a 20% solution of perfluorohexyl sodium sulfin~te in water. Under agitation (445 rpm) the reactor was heated to 71~C and pressurized to 2.00 MPa (290 psig) with a mixture of 95% TFE and 5% propylene. Using a con.~t~metric pump, a 10% solution of anll,lo~ m persulfate in water was fed to the reactor at a rate of 135 g per hour.
When the pressure dropped, indicating reaction, the monomers were replenished ina Illi~Ul'e of 75% '~ and 25% propylene to ~ ;ll 2.00 ~a (290 psig). After 2s 389 g ofthe ammonium persulfate solution was added, this feed was stopped and the reaction continued thermally until a total of 4000 g of monomer was consumed.
This was achieved 4 hours and 45 minlltes after the reaction started to give a calculated average reaction rate of 60 g/l-h. At that time, the agitation was decreased and the reactor was cooled and vented. The reactor was drained and a highly transparent latex was obtained. The latex was co~ ted by dripping into a m~gnçsil1m chloride solution in water, to yield a snow-white elastomer gum which CA 02206092 1997-0~-27 W O96/18665 PCTrUS95/14260 was washed several times with hot deionized water and dried overnight at 110~C.
There was obtained a snow-white elastomer gum with a Mooney viscosity ~L 1+10 (~ 121~C) of 25.
5 Co~ u~Li~e Example C1 Polymer was prepared as in Example 5, but with omission of the perfluorohexyl sodium sl~lfin~te and all the ammonium persulfate was batch chal~ed at the beginning instead of pumping it in over time. The polymerization was extremely slow and the polymerization was abandoned after 3 hours. Only 368 g of10 monomer was con~l~med over this time to give a calculated average reaction rate of 9 g/l-h.
Co",p~ing F.~mples 1-5 with Colllpal~Live Example C1 illustrates the effect ofthe perfluoro alkyl s--lfin~te. In Examples 1-5, in which perfluoro alkyl 15 s llfin~te was used, the reaction proceeded rapidly. In Colllpal~Li~e Example C1, even with batch charging the persulfate, the rate was much slower than in Examples 1-5. Note that the rate in Colllpa~aLi~le Example C1 would have been even slower if the persulfate had been charged over time as in Examples 1-5, rather than batch chalged.
Example 6 A 19-liter vertically-stirred polymerization reactor was charged with 14,000 g deionized water, 9 g KOX 50 g K2HPO4, 81 g ammonium perfluoro oct~noate, and 162 g of a 20% solution of C6F,3SO2Na in deionized water. The 25 reactor was then al~ellla~ely evacuated and purged with N2 until ~2 level is less than 50 ppm. The reactor was then ev7~cll~te~17 the temperature raised to 71~C, and the agitation set at 445 rpm. Next, the reactor was charged with 455 g of l~ and 8.26 g of propylene to give a pressure of 1.52 MPa (220 psig). The polymerization was initi~ted by feeding a 5% solution of (NH4)2S208, in deionized water to the 30 reactor by means of a metering pump at approx;",~ely 4 g/min until 1 equivalent of (NH4)2S208 was fed (approxilllately 370 g of soln.). Upon the observation of a pressure drop, the running feed, which consisted of 93% TFE and 7% propylene, WO 96/18C65 PCTrUS9~/14260 was started and continuously adjusted by the reactor's control system in order to the desired pre~ure. The polyme-~ion was halted by slowing the agitation to 60 rpm after 3,784 g of TFE and 278 g of propylene had been fed, 4 hours after start of mnning feed to give a c~lcul~ted average reaction rate of73 g/l-h. The reactor was then vented, cooled, and drained to isolate the latex. The resulting polymer was isolated by freeze co~ tion~ washed six times with hot deionized water, and dried overnight in an oven at 100~C. The polymer, when analyzed by DSC, exhibited a broad melting tr~n.~ition with a peak melting tempe,a~re of 187~C and a small secondary melt-transition with a peak melting-te--.pe-~lule of 320~C which integration ofthe large and small melt-peaks shows accounts for 0.5% of the total heat of fusion (see Fig. 1). El~mPnt~l analysis of the polymer for carbon, hydrogen, and fluorine, indicated a polymer composition of 92.3% TFE and 7.7% propylene. The Melt Flow Index (~I) of the polymer was detellll,lled to be 13 g/10 min. ~ 265~C and 2.5 kg applied load.
Fx~ plc7 A 150-liter vertically-stirred polymerization reactor was charged with 120,000 g deionized water, 78 g KOH, 430 g K2HP04, 694 g ammonium perfluoro oct~no~tP:~ and 1,023 g of a 20% solution of C4FgSO2Na in deionized water. The reactor was then alternately ev~cu~ted and purged with N2 until O2 level is less than 50 ppm. The reactor was then ev~c~l~ted, the temperature raised to 71~C, and theagitation set at 210 rpm. Next, the reactor was charged with 3929 g of TFE and 79 g of propylene to give a pl e~u.e of 15.2 bar (220 psig). The polymerization was initi~ted by feeding a 5% solution of (N~)2S2Og in deionized water to the reactor by means of a metering pump at approxi. "~tely 25 g/min until 1 equivalent of (~H4)2S208 was fed (appl ~ ately 3,200 g of solution). Upon the observation of a pressure drop, the running feed, which consisted of 91% 'l ~ ~ and 9% propylene, was started and continuously adjusted by the reactor's control system in order to ~ the desired pressure. The polymerization was halted by slowing the agitation after 31,300 g of TFE and 3,080 g of propylene had been fed, 5 hours after start of running feed to give a calculated average reaction rate of CA 02206092 1997-0~-27 W O96/18665 PCTrUS95/14260 57 gA-h. The reactor was then vented, cooled, and drained to isolate the latex. The resulting polymer was co~ ted by adding HCI to the latex, gran~ ted, washed six times with d~ ecl water, and dried overnight in an oven at 120~C. The polymer, when analyzed by DSC, ~,A}.ibiled a broad melting transition with a peak melting tempc;, ~l~lre of 154~C and a small secondary melt-transition with a peak melting-telnpt. c-L~lre of 316~C which i,.leg. ~lion of the large and small melt-peaks shows accounts for 2.8% of the total heat of fusion (see Fig. 2). Elpm~nt~l analysis of the polymer for carbon, hydrogen, and fluorine, indicated a polymer composition of 90.9% 1~ ~ and 9.1% propylene. The Melt Flow Index (~I) of the polymer was determined to be 3.3 g/10 min. (~ 265~C and 2.16 kg applied load.
Example 8 An 86-liter vertically-stirred polymerization reactor was charged with 52,000 g deionized water, 140 g KOH, 300 g ammonium perfluoro oct~no~t~, 110 g Na2SO3, 2 g CuSO4-5H2O, and 1,000 g of a 20% solution of C6Fl3SO2Na in deioni~ed water. The reactor was then alternately ev~c~ted and purged with N2 until C~2 level is less than 50 ppm. The reactor was then evac~te(l, the te---pe-~ re raised to 54~C, and the agitation set at 150 rpm. Next, the reactor was charged with 1256 g of l~k; and 37.18 g of propylene to give a pressure of 0.83 MPa (120 psig). The poly.. e.iGalion was initi~ted by feeding a 10% solution of ~NH4)~S20g, in deionized water to the reactor by means of a metering pump at approximately 3 g/min until 778 g of soln. was fed. Upon the observation of a pressure drop, the running feed, which consisted of 88% 1~ and 12% propylene, was started and continuously adjusted by the reactor's control system in order to 25 ...~ the desired pressure. The polymerization was halted by slowing the agitation to 30 rpm after 7,825 g of TFE and 1080 g of propylene had been fed, 5 hours after start of running feed to give a calculated average reaction rate of 34 g/l--h. The reactor was then vented, cooled, and drained to isolate the latex. The rçs~ inp polymer was isolated by freeze coagulation, washed six times with hot 30 deionized water, and dried overnight in an oven at 100~C. The polymer, when analyzed by DSC, exhibited a broad melting transition with a peak melting W Og6/18665 PCTnUS9~114260 t~ el~Ult; of 103~C and no secondary melt-transition above 300~C (see Fig. 3).
Elemental analysis of the polymer for carbon, hydrogen, and fluorine, in :licated a polymer composition of 88.1% 1~ and 11.9% propylene. The Melt Flow Index (MFI) of the polymer was deLe. ~uned to be 7 g/l 0 min. ~ 1 90~C and 2.5 kg 5 applied load.
,. .
Co."pa,ali~re Example C2 A l9-liter vertically-stirred poly.,lel~alion reactor was chal~ed with 14,000 g deionized water, 9 g KOH, 50 g K2HOP4, and 81 g ammonium perfluoro 10 oct~n~te The reactor was then alle.n-d~ely ev~c l~ted and purged with N2 until O2 level is less than 50 ppm. The reactor was then evacu~terl~ the temperature raised to 71~C, and the agitation set at 445 rpm. Next, the reactor was cha-~;ed with 414 g of l~-~ and 11.2 g of propylene to give a pressure of 1.59 MPa (230 psig).The pol~lllt;-~Lon was initi~ted by feeding a 5% solution of(NH4)2S2O8 in 1S deionized water to the reactor by means of a metering pump a~p. o~.--ately 14 g/min until 1 equivalent of ~)2S2O8 was fed (approxiln~ y 370g of soln.).
No pressure drop, which would intlic~te the onset of polymerization, was observed.
Co.npa.~Li~re Fx~mrle C3 Following the procedure of example 6 of U.S. Pat. No. 3,933,733, supra, an 86-liter vertically-stirred polymerization reactor was charged with 60,000 g deionized water, 300 g NaOH, 300 g ammonium perfluoro octanoate, and 12 g Na2SO3. The reactor was then allel ,.dlely ev~cl~tecl and purged with N2 until O2 level is less than 50 ppm. The reactor was then evacuated, the temperature raised 25 to 60~C, and the agitation set at 150 rpm. Next, the reactor was charged with2100 g of'l~ and 46.~ g of propylene to give a pressure of 1.72 MPa (2~0 psig).
The polymerization was initi~te~ by feeding a 5.7% solution of ~I4)2S208 in deionized water to the reactor by means of a metering pump at maximum pump speed (approx;...~lçly 100 g/min) until 432 g of soln. was fed. Upon the 30 observation of a pressure drop, the running feed, which consisted of 88% 1~ and 12% propylene, was started and continuously adjusted by the reactor's control CA 02206092 1997-0~-27 system in order to ~ - the desired pressure. The polyl"e.i~Lion was halted after 6 hours by slowing the agitation to 50 rpm, during which time 3,458 g of TFE
and 489.5 g of propylene had been fed to give a c~lc~ ted average reaction rate of 11 gA-h. The reactor was then vented, cooled, and drained to isolate the 6% solids latex. The resl-lting polymer was i~ol~ted by freeze co~ tion~ washed six times with deionized water, and dried overnight in an oven at 100~C. The polymer, whenanalyzed by DSC, exhibited two melting transitions with peak melting temperatures of 105~C and 316~C (see fig. 4). Integration ofthe large and small melt-peaks shows that 26% of the total heat of fusion is attributable to the 316~C peak 0 (See Fig. 4). Fl~m~nt~l analysis of the polymer for carbon, hydrogen, and fluorine, indica~ed a polymer composition of 88.1% 1~ and 11.9% propylene. The Melt Flow l[ndex (~I) of the polymer was determined to be zero g/10 min ~ 265~C and 15 kg applied load.
Colll~al ~ e Example C4 Following the procedure described in U.S. Pat. No. 4,463,144, supra.
except using anl,llol~ium perfluoro oct~no~te as the emulsifier, an 86-liter vertically-stirred polymerization reactor was charged with 51,600 g deionized water, 5,600 g t-butanol, 281 g ammonium perfluoro octanoate, 167 g KOH, 857 g K2~04, 3.4 g Na2EDTA, and 2.8 g FeSO4-7H20. The reactor was then alternately evacu~ted and purged with N2 until O2 level is less than 50 ppm. The reactor was then ev~c~te~l, the tenlpel~L~lre raised to 27~C, and the agitation set at 130 rpm. Next, the reactor was charged with 2170 g of 1 ~ ~ and 64.1 g of propylene to g*e a pressure of 1.52 MPa ~220 psig). The polymerization was initi~ted by feeding a solution consisting of 175 g +Na~SO2CH20H, 15 g Na2EDTA, and 18.4 g KOH in 1810 g of deionized water, to the reactor by means of a metering pump (applox;.~-~tçly 3 g/min) until 950 g of soln. was fed. Upon the observation of a pressure drop, the running feed, which consisted of 88% 1~ and 12% propylene, was started and continuously adjusted by the reactor's control system in order to ,..~ the desired pressure.
The polymerization halted after 8,479 g of 1~ and 1,173 g of propylene had been fed, 5.5 hours after start of running feed to give a calculated average reaction rate of 30 g/l-h. The reactor was then vented, cooled, and drained to isolate the polymer suspension. The r~.cl-lting polymer was isolated by filtration, washed six times with hot deionized water, and dried overnight in an oven at 100~C. The polymer, when analyzed by DSC, e.~llibiLed two melting transitions with peak melting t~ elaL~lres of 114~C and 321~C (see Fig. ~). Integration ofthe large and small melt-peaks shows that 27% of the total heat of fusion is aUl;bulable to the 321~C peak (see Fig. 4). Ele-nPnf~1 analysis of the polymer for carbon, hydrogen, and fluorine, indicated a polymer composition of 88.8% TFE and 11.2% propylene.
The Melt Flow Index (MFI) ofthe polymer was determined to be 59 g/10 min (~
o 265~C and S kg applied load.
Examples 6-8 and Comparative Examples C2 and C3 show that unlike the semi-crystalline polymers of the prior art, the semi-crystalline polymers of this invention have very little if any melt transitions above 300~C. It is believed that the improved melt-processing of semi-crystalline polymers of this invention is due in part to the absence of significant melt-transitions above 300~C.
FT-IR spectra of thin films of the resultin~ polymers showed no observable carbonyl absorptions for Examples 6-9, a relatively large carbonyl absorption at1695 cm~l for Col~lp~live Example C2, and a moderate carbonyl absorption at 1744 cm-l for Comparative Example C3 . This indicates that the polymers of this invention do not contain significant amounts of carbonyl-cont~ining end-groups.
Various modifications and alterations of this invention will be apparent to those skilled in the art without departing from the scope and spirit of this invention and this invention should not be restricted to that set forth herein for illustrative purposes.
Claims (10)
1. A method for the preparation of fluorine-containing polymer comprising, polymerizing at temperatures above about 50°C, under free-radical conditions, an aqueous emulsion or suspension of a polymerizable mixture comprising a fluorine-containing ethylenically-unsaturated monomer, an allylic-hydrogen containing olefin monomer, a fluoroaliphatic-group containing sulfinate, and an oxidizing agent capable of oxidizing said sulfinate to a sulfonyl radical.
2. The method of Claim 1 wherein said fluorine-containing monomer is selected from the group consisting of vinylidene fluoride, hexafluoropropylene, chlorotrifluoroethylene, 1-chloropentafluoropropene, perfluoroalkyl vinyl ethers, tetrafluoroethylene, 1-hydropentafluoropropene, dichlorodifluoroethylene, 2-hydropentafluoropropene, vinyl fluoride, trifluoroethylene, 1,1-dichlorofluoroethylene, perfluorodiallylether, and perfluoro-1,3-dioxoles, and wherein said allylic-hydrogen containing olefin monomer is a mono-olefin consisting of carbon, hydrogen, and halogen atoms.
3. The method of Claim 1 wherein said allylic-hydrogen containing olefin monomer is selected from the group consisting of propylene, butylene, isobutylene, and 1,1,2-trifluoropropene
4. The method of Claim 1 wherein said sulfinate is Rf(SO2Ml/x)n where Rf is a fluoroaliphatic group, M is a hydrogen atom or a cation of valence x, and n is 1 or 2.
5. The method of Claim 1 wherein the mixture of monomers in said polymerizable mixture consists essentially of monomers selected from the group consisting of tetrafluoroethylene, vinylidene fluoride, and propylene.
6. A semi-crystalline polymer comprising interpolymerized units derived from tetrafluoroethylene and allylic-hydrogen containing olefin monomer,wherein less than 10% of the total heat of fusion is attributable to a secondarymelt-transition above 300°C as shown by the heating curve from Differential Scanning Calorimetry.
7. The polymer of Claim 6 wherein said allylic-hydrogen containing olefin monomer is a mono-olefin consisting of carbon, hydrogen, and halogen atoms.
8. The polymer of Claim 6 wherein said allylic-hydrogen containing olefin monomer is propylene.
9. The polymer of Claim 6 wherein said polymer consists essentially of interpolymerized units derived from tetrafluoroethylene and allylic-hydrogen containing olefin monomer.
10. Shaped article comprising the polymer of Claim 6.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US35550694A | 1994-12-14 | 1994-12-14 | |
| US08/355506 | 1994-12-14 | ||
| PCT/US1995/014260 WO1996018665A1 (en) | 1994-12-14 | 1995-11-06 | Fluorine-containing polymers and preparation thereof |
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| Publication Number | Publication Date |
|---|---|
| CA2206092A1 true CA2206092A1 (en) | 1996-06-20 |
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| CA 2206092 Abandoned CA2206092A1 (en) | 1994-12-14 | 1995-11-06 | Fluorine-containing polymers and preparation thereof |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115340459A (en) * | 2021-05-13 | 2022-11-15 | 中昊晨光化工研究院有限公司 | Industrial method for removing impurities in trifluoromethyl hypofluorite |
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1995
- 1995-11-06 CA CA 2206092 patent/CA2206092A1/en not_active Abandoned
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115340459A (en) * | 2021-05-13 | 2022-11-15 | 中昊晨光化工研究院有限公司 | Industrial method for removing impurities in trifluoromethyl hypofluorite |
| CN115340459B (en) * | 2021-05-13 | 2023-12-26 | 中昊晨光化工研究院有限公司 | Industrial method for removing impurities in trifluoromethyl fluoacid ester |
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