claim: 1. A process which comprises polymerizing a monomeric mixture of a dichlorohexafluorobutene selected from the group consisting of 2,3- dichlorohexaffuorobutene-2 and 4,4-dichlorohexaffuorobutene-I and a partially halogenated 1,3-butadiene selected from the group consisting of trifluorobutadiene, 1,1- difluoro-2-methyl1,3-butadiene, fluoroprene and chloroprene, said mixture containing between about 20 mole percent and about 60 mole percentdichlorohexafluorobutene and the remaining major constituent being the partiallyhalogenated 1,3butadiene, at a temperature betiveen about -20' C. and about 100' C. in the presence of a polymerization promoter selected from the gr6up consisting of a water soluble peroxy promoter and an organic peroxy promoter. 2. A process which comprises polymerizing a monomeric mixture of a dichlorohexafluo,robutene selected from the group consisting of 2,3- dichlorohexafluorobutene-2 and 4,4-dichlorohexafluorobutene-1 and a partially halogenated 1,.3-butadiene selected from the group consisting of trifluorobutadiene, 1,1- diffuoro-2-methyl-1,3butadiene, fluoroprene and chloroprene, said mixture containing between about 20 mole percent and about 50 mole percentdichlorahexafluorobutene and the remaining major constituent being the partiallyhalogenated 1,3-butadiene, at a temperature between aboiit -20' C. and about 100' C. in the presence of a polymerization promoter selected from the group consisting of a water soluble peroxy promoter and an organic peroxy promoter. 3. A process which comprises polymerizing a mono- fi@orobutene selected meric mixture of a dichlorohexa from the group consisting of 2,3-dichlorohexafluorobutene-2 and 4,4- dichlorohexafluorobutene-I and trifluorobutadiene, said mixture containing between about 20 mole percent and about 60 mole percent dic hlorohexafluorobutene and the remaining major constituent being trifluoro-1,3-butadiene, at a temperature between about -20' C. and about 100' C. in the presence of a polymerization promoter selected from the group consisting of a water soluble peroxy promoter and an organic peroxy promoter. 4. A process which coniprises polymerizing a monomeric mixture of a dichlorohexafluorobutene selected from the group consisting of 2,3-dichlorohexafluorobutene-2 and 4,4- dichlorohexafluorobutene-1 and 1,1-difluoro-2-methy l-1,3-butadiene, said mixture containing between about 20 mole percent and about 60 mole percent dichlorohexafluorobutene and.the remaining major constituent being 1,1-difluoro-2- methyl-1,3-butadiene, at a temperature between about -20' C. and about 100' C. in the presence of a polymerization promoter selected from the group consisting of a water soluble peroxy promoter and an organic peroxy promoter. 5. A process which comprises polymerizing a monomeric mixture of a dichlorohexafluorobutene selected from the group consisting of 2,3- dichlorohexafluorobutene-2 and 4,4-dichlorohexafluorobtitene-I and fluoroprene, said mixture containing between about 20 mole percent and about 60 mole percent dichlorohexaflucrobutene and the remaining major constituent being fluoroprene, at a temperature between about -20' C. and abo-ut 100' C. in the presence of a polymerization promoter selected from the grolip consisting of a water soluble peroxy promoter and an organic peroxy promoter. 6. A process which comprises polymerizing a monomeric mixture of a dichlorohexafluorobutene selected from the group consisting of 2,3- dichlorohexafluorobutene-2 and 4,4-diclorohexaffuorobutene-1 and a chloroprene, said mixture containing between about 20 mole percent and about 60 mole percent dichlorohexafluorobutene and the remaining major constituent being chloroprene, at a temperature bet,,veen about -20' C. and about 100' C. in the presence of a polymer ization pro-

9 moter selected from the group consisting of a water soluble peroxy promoter and an organic peroxy promoter. 7. A copolymer of about I mole percent to abolt 30 mole percent of a dichlorohexafluorobutene selected from the group consisting of 2,3- dichlorohexafluorobutene-2 and 414-dichlorohexafluorobutene-1 and correspondingly about 99 mole percent and about 70 mole percent of a partially halogenated 1,3- butadiene selected from the grotip consisting of tr ifluorobutadiene, 1,1-difluoro2methyl-1,3-butadiene, ffuoroprene and chloroprene. 8. A copolymer of about 1 mole percent to about 30 mole percent of a dichlorohexafluorobutene selected from the group consisting of 2,3-dirhlorohexafluorobutene-2 and 4,4-dichlorohexafluorobutene-1 and correspondiiigly about 99 mole percent to about 70 mole percent of t rifluorobutadiene. 9. A copolymer of about I mole percent to about 30 mole percent of a dichlorohexafluorobutene selected from the -roup consisting of 2,3- dichlorohexafluorobutene-2 and 4,4-dichlorohexaflucrobutene-I and correspondingly about 99 mole percent to about 70 mole percent of 1 ,1difluoro-2-me'@hyl-1,3- butadiene. 10. A copolymer of at-out 1 mole percent to about 30 mole percent of a dichlorohexafluorobutene selected from the group consisting of 2,3- dichlorohexafluorobL,tene-2 and 4,4-dichlorohexafluorob@,itene-I and coirespond@'ngly about 99 mol-@ percent to about 70 mole percent of fluoroprene. 11. A copolymer of about 1 mole percent to about 30 mole percent of a dichlorohex&quorobutere selected from the groiip consisting of 2,3- dichlorohexafluorobutene-2 and 4,4-dichlorohexafluorobutene-I and coi-respondin.-ly abo,,it 99 mole percent to about 70 mole percent of chloroprene. 12. A process which comprises polymerizing a monomeric mixtiire of 2,3- dichlorohexafluorobutene-2 an(i a partially halogenated1,3-butadiene selected from the group consisting of trifluorobutadiene, 1,1-difluor (i-2methyl-1,3-butadiene, fluoroprene and cliloroprene, said mixture containing between about 20 mole percent and about 60 mole percent 2,3-dichlorohexafluorobutene2 and the remaining major constituent being said partiilly halo-enated 1,3-butadiene, at a temperature between ab,ut -20' C. and about 100' C. in the presence of a polymerization promoter selected from the group coi,sisting of a water soluble peroxy promoter and an organic peroxy promoter. 2,914,514 10 13. A process which comprises polymerizing a monomeric mixture of 4,4-dichlorohexafluorobutene-1 and a partially halogenated 1,3-butadiene selected from the groi-ip consisting of tr-'@fluorobutadiene, 1,1-difluoro-2- methyl-1,3-butadiene, fluoroprene and chloroprene, said mixture containing between about 20 mole percent and abotit 60 mole perccnt 4,4- dichlbrohexafluorobutene-1 and the remaining major constituent being said partially halogenated 1,3-butadiene, at a temperature between 10 about -20' C. and about 100' C. in the presence of apolymerization promoter selected from the group consisting of a water soluble peroxy promoter and an organic peroxy promoter. 14. A copolymer of about 1 mole percent to about 30 15 mole percent of 2,3-dichlorohexafluorobutene-2 and correspondingly about 99 mole percent to about 70 mole percent of trilluo ro-113-butadiene. 15. A copolymer of about I mole percent to about 30 mole p@rcent of 4,4-dichlorohexafluorobutene-1 and 20 correspondingly about 99 mole percent to about 70 mole p--rcent of trifluoro1,3-butadiene. 16. A process -,@ihich comprises polyrierizing in an emulsion system a monomeric mixture of a dichlorohexafluorobutene selected from the group consisting of 2,3- 25 dichlorohexafluorobutene-2 and 4,4-dichlorohexafluorobutene-1, and a partially halogenated 1,3-butadiene selected from the group consisting of trifluorobutadiene, 1,1-difluoro-2-rqethyl-1,3-butadiene, fluoroprene and chloroprene, said mixture containin@ between about 20 mole 30 @ercent and about 60 mole percent diclilorohexafluorobutene and the remaining major constituent being the partially halogenated 1,3 butad,.ene, at a temperature between about 5' C. and about 100' C. and a pH of bet@veen about 7 and 11 in the presence of a polymeriza35 tion promoter selected from the group consisting of a water soluble peroxy promoter and an organic peroxy promoter. References Cited in the file of this patent 40 UN ITED STATES PATENTS 217 05,706 Ditt man et al - ---------- Apr. 5, 1955 FO REIGN PATENTS 45 478, 511 Can ada --------------- Nov. 13, 1951 494, 441 Can ada --------------- July 14, 1953

UNITED STATES PATENT OF'.FICE CERTIFICATE OF CORRECTION' Patent No. 2,914,514 November 24, 1959 Elizab.eth S. Lo It is hereby.certified that error appears in the above numbered patent requiring correction and that.the said Letters Patent should read as corrected below. Column 4, 'line 2, for "10 parts" read 100 parts column 7, line 14, for "D-470-49T" read D-471- 49T Signed and sealed this.12th day of July 1960. (SEAL) Attest: KARL H. AXLINE R O B E R T C . W A T S O N Attesting Offic'er Commissioner of Patents

United States Patent@ Office 22914@514 2,91e@',,514 COPOLYM[ERS OF DICHLOROHEXAFLUOROBUTENF, Elizabeth S. Lo, Elizabeth, N.J., assignor, by mesne as. signments, to @Nftnesata AUning and Manufacturing Company, St. Paul, Minn.,,a corporation of Delaware No Drawing. AppHeation April 30, 1956 Serial 'No. 581,328 @16 Claims. (Cl. 260-87.5) This invention relates to, and has for its @ object, the preparation of new and useful copolymers of dich':orohexdfluorobutene. More particularly, the invention relates to, and has for its objeot, the preparation of thermoplastic copolymers of aichlorohexafluorobutene, having a wide variety df commercial uses and applications. Still more particularly, the invention relates to, and has for its object, a method for the preparation of these copolymers. Other objects and advantages inherent in the inv6ntion will become apparent to those skilled in the art from the accompanying description and disclosure. In accordance with the present invention, dichloroh exafluorobutene is copolymerized with a partially halogenated 1,3-butadiene to produce new and useful copolymeric compositions. In this respect, it is found that the presence of relatively small amounts of the dichlorohexafluorobutene in the copolymeric product of -lis monoiner and the partially halogenated 1,3-butadiene results in a thermoplastic composition of improved resiliency an rubbery characteristics, not otherwise possessed by the butadiene homopolyn-ier itself. In this respect, it is also found that these copolymeric compositions possess increased tensile strength, increased resistance to oil and hydrocarbon fuels, improved flow-properties and improved chemical and physical stability over any of the aforementioned butadiene comonomers alone, when employed in the form of their corresponding homopolymers. These polymeric compogitions of dichlorohexafluorobu@ tene and the aforementioned partially halogenated buta dienes, constitute valuable macromolecules and are adaptable to a wide variety of commercial uses. They possess low temperature flexibility, in addition to the aforementioned properties of chemical and physical stability and resistance to oil and hydrocarbon fuels. They are also selectively soluble in various commercial solvents and serve as durable, flexible, protective coatings on surfaces which are subjected to environmental conditions in which they may come into cbntact with,any o,f the aforeinentioned corrosive substances. In general, as more fully hereinafter disclosed, the copolymeric compositions of the present invention are produced from the polymers of monomeric mixtures containing dichlorohexafluorobutene (e.g., 4,4-dichlorohexafluorobutene-I or 213- dichlorohexafluorobutene-2) and the partially halogenated 1,3-butadiene as a cornonomer such as trifluoro-1,3-butadiene (e.g., 1 ,1,2-trifluoro-1,3butadiene or 111,3- trifluoro-1,3-butadiene); 1,1-difluoro2-methyl-1,3-bufadiene; fluoroprene (2-fluoro-1,3- butadiene); or chloroprene (2-chloro-1,3-btitadiene). The copolymerization reaction is carried out at temperatures between about -20' C. and about 150', C., with intermediate temperature ranges being @elected with reference to the specific polymerization system employed. The most useful thermoplastic copolymeric compositions of the present invention are copolymers produced from monomeric mixtures containing between about 20 mole percent and about 60 mole.percent of the dichlorohexafluorobutene and the remaining major constituent being Patented Nov. 24, 1959 any of 'the aforementioned partially halogenated 1,3-L butadienes. The preferred copolymeric coinpositions of the present invention are copolymers produced from monomeric mixtiires @ontaining between about 20 mole perrent and about 50 mole percent of the dichloro fluorobuteni3 and the remaining major constituent bein'g any of the aforementioned 1,3-butadiene comonomers-. I In producing copolymeric compositions from the @ior&mentioned mixtures cdntaining I between ab6ut ?O mole 10 percent and aboiit 60 triole percent of the dich lorohexafluorobutene and the remaining major constituent @being any of the aforementioned partially halogenb@ted 1,3buta:dienes, it is f6und that the finished copol@m6iilc produtt contains between about 1 mole percent and 15 about 30 mole percent of 'the dichlorohexafluorobuted I e and the remaining major constituent being any of th'e aforementioned butadienes. In producing copolymeric compositions from the @forementioi2ed monomeric@nii . x@ tureg containing between about 20. mole percent and 2o about 50 inole percent of the dichlorohexafluorobuti@nd, it is found that the finished copolymeric @product . con7 tains between about 1 mole percent and about 10 @mole percent of the dichlorohexafluorobutene and the remainin,@ major constituent being any of the dorementioned 25 partially halogenated 1,3-butadienes. The copolymeric compositions of the present invention are preferably prepared by carrying out the'polym6rization reaction in the presence of a free radicalforihiiig promoter. For this purpose, the polymerizatibn reaction 30 is carried out by employing a water-soluble peroyy type initiator in a watersuspension type recipe or:an org@;iie peroxide initiator in a bulk-type system. The water-suspension type recipe is preferred@ The water@suspension type system contains a water35 soltible peroxy-type initiator, which is preferably present in the form of an inorganic persulfate such as pota sium persulfate, sodium persulfate or ammonium petsulfate. In addition, the water-suspension type recipe system may also contain, in some instances, a variable-valence metal 40 salt, for example, an iron salt such as ferrous sulfate or ferrbus nitrate to accelerate the copolymerization reaction. The water-soluble initiator present in the wat&rsuspension type recipe system comprises between about 0.1 and about 5 parts by weight per 100 parts of tot@l 45 monomers present. The variable-valence metal sbLIt is preferably 6mployed in an amount bet@veeii about 0.0 . I and about 0.2 parts by weight p&r 100 parts of ;total monomers present. It is also desirable, in some iii-' stances, in these water-suspension type recipe 8yst6ms, 5o that a reductant be present, preferably in the forni of a bisulfite, such as sodium bislilfite, potassium bisiilfite, sodium metabisulfite or potassium metabisulfite. The reductant cotftprises between aboi@t 0.05 and about 5 parts by weight @oer 100 parts of total monomers present; 55 prefer@bly the reductant comprises between about 0.1 and about 2 parts by weight per 100 parts of total monomers present. In these water-suspension type recipe systems, it is desirable to eniploy an emulsifying agent. This emul6o sifying agent is present either in.the f6rm of an aliphatic metal acid-salt having from 14 to 20 carbon atoms per molecule, or in the form of a halogenated-organic acid or salts thereof, having from 6 to 18 carbon atoms per molecule. A typical example of the f6rmer i s potassium 65 stearate. Typical examples of the halogenated-organic acid or salts thereof, serving as emulsifying agents in the above mentioned water-suspension type recipe sys-' tems, are polyfluorocarboxylic acids (e.g., perfluorooctanoic acid) or perfluorochlorocarboxylic acid salts (e.g., 70 trifluorochloroethylene telomer acid soaps). 'I@le polyfluorocarboxylic acids which may be employed are such as those disclo@ed in U.S. Patent No, Z,559,752; and tho

2,914,514 3 non-acidic derivatives of the acids disclosed therein as being effective dispersing agents may also,be used in the process of the present invention. The perfluorochlorocarboxylic acid salts which may be used in accorddnce with this invention are those disclosed in co5 pending application Serial No. 501,782, now Patent No. 2,806,867 filed April 18, 1955, as being usbful dispersing agents are present in an amount between about 0.5 and about 10 parts by weight per 100 parts of total monome rs present. 10 The. polymerization reaction is preferably conducted under alkaline conditions. It is desirable, therefore, that the pH be maintained between about 7 and I I in order to prevent gelling of the resulting polymeric product, a condition which often causes slow-down or stoppage of 15 the polymerization reaction. In this respect, it should be noted that ft is sometimes necessary to maintain the pH of the system within the aforementioned pH limits by the addition of suitable buffer agents. Typical examples are sodium borate and disodiurn phosphate. 20 As indicated above, the polymerization reaction may also be carried out with the initiator being present in the form of an organic peroxide in a bulk-type - polymerization system. Of these organic peroxide proinoters, halogen-sustituted peroxides are most desirable. A pre25 ferred promoter of this type is trichloroacetyl peroxide. Other halogen-substituted organic peroxides for - carrying out the polymerization reaction are trifluor odichloropropionyl peroxide, trifluoroacetyl peroxide, d ifluoroacetyl peroxide, chloracetyl peroxide, 2,4-dichlorobenzoyl per30 oicide and dichlorofluoroacetyl peroxide. As previously indicated, the polymerization reaction is carried out ' in general, at a temperature between about -20' C. and about 150' C. When the p olymerization reaction is carried out employing a water-suspension type 35 recipe, temperatures between about 5' C. and about 100' C. are preferably employed. When the p olymerization rea@tion is carried out in the presence of an organic peroxide initiator in a bulk-type polymerization system, temperatures over the entire range of between about 40 -20' C. and about 150' C. are preferably - employed depending upon the decomposition temperature of the promoter. The polymerization reactions described herein to produce the polymeric compositions of the present invention are carried out under autogenous con- 45 ditions of pressure. These pressures may vary from about atmospheric pressure to as high as 2000 pounds per square inch. However, in general, these pressures do not rise above approximately 500 pounds per square inch. 50 As previously indicated, the polymeric compositions of the present invention are particularly suitable and useful,when employed in the form of durable, - flexible coatings on a wide variety of surfaces, and particularly on surfaces which are subjected to dislortion in normal 56 uses, such as fabric surfaces. For this purpose, the polynieric composition may be dissolved in various commercial solvents. Particularly useful solvents - comprise the aliphatic and aromatic esters, ketones and h'alogenated hydrocarbons. Typical examples of these - solvents 60 are di-isobutyl ketone, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate and 1,1,2-triflu orotrichloroethane. In this respect, it should be noted that it is often desirable to regulate the molecular weight of the polymeric compositions of the present invention in order to 6,5 obtain greater solubility in organic sol-vents. It is found that the addition of various polymerization modifiers appreciably reduces the molecular weiglit of the polymeric compositions and increases their solubility, without affecting, unduly, the overall yield. Suitable polymeri- 70 zation modifiers include chloroform (CHC13), Freon-I 13 I CF2CICFC12), carbon tetrachloride (CC14), trichloroacetyl chioride (CC13COCI), bromotri chloromethane (CBrCls), dodecyl mercaptan (Cl2H25SH) and mixed. 4 added in amounts between about 0.01 and about 10 parts b weight per 10 parts of fotal monomers charged to @ y the polymerization reaction. Chloroform is preferred. The foflowing examples are offered for a better understanding in producing the thermoplastic copolymeric compositions of the present invention and are not to be construed as limiting its scope. Example I A heavy-walled glass polymerization tube of about 20 ml. capacity was flushed with nitrogen and then charged with I ml. of a solution prepared by dissolving 0.4 grams of sodium metabisulfite in 20 ml. of water. The contents of the tube were then frozen. The tube was next connected to a gas-transfer system and evacuated at liquid nitrogen temperature. Therefore, there was added to the tube 4 ml. of a solution prepared by dissolving 1.0 gram of potassium persulfate in 80 ml. of water. Thereafter, there was added to the tube 5 ml. of a solution prepared by dissolving 5 grams of potassium stearate in 100 ml. of water, this solution having previously been adjusted to a pH of 10. The contents of the tube were then refrozen, and the tube was next connected to a gastransfer system and evacuated at liquid nitrogen temperature. To the frozen contents of the tube were added, by distillation, 2.4 grams of 4,4-dichlorohexafluorobutene-I and 2.6,grams of 1,1,2-trifluoro-1,3-butadiene, whi@h comprised a 30/70 molar ratio. The,4,4-dichlorohexafluorobutene-I monomer is prepared as follows: Trifluorochloroethylene is telomerized in the presence @of sulfuryl chloride, employing benzoyl peroxide as a promoter, at a temperature of approximately 95' C. for a @eriod of 4 hours, to produce the telomer dimer product, C l-(CFT-CFCI)2-C" 1,2,4,4- tetrachlorohexafluorobutarle, having a boiling point of 134' C. and an index of refraction (nD20) of 1.3820. To a I L. round-bottom flask equipped with a magnetic stirrer, a dropping funnel, and a Friedrich condenser (which, in turn, is attached to a bubbler and cold trap maintained at a temperature of @68' C.) there is charged 357 grams (1.17 mol) of the aforementioned 1,2,4,4-tetrachlorohexafluorobutane. The contents of the flask are then heated to l@0'. C. Thereafter, 105.5 grams (0.63 mol) of triethyl phosphite are added dropwise over a period of 3 hour@. The heating is continued for an additional period of I h6ur, after which time the generation of gas has ceased. The cold trap is found to contain only liquefied ethyl chloride (25.6 grams). The 1,1-12-trifluoro-1,3-butadiene monomer was obtained by adding dibromofluoromethane to 1-fluoropropene to produce the adduct CF2BrCHFCHBrCH3, which, upon dehydrobromination, yielded CF2@CFCHCH2 B.P. 4.8' C.-8.0' C. 1-fluoropropene was prepared by the following sdrie@ of reartions: (1) R.T. CHCI=CIEECH3 + Br2 CHCIBrCHBrClIs (2) sealed bomb ORCIBrCHBrCE3 + TTF/1190 ------- CHCIFCHBROH, R.T.; 18 bours n-propanol (3) CHCIFCHBrCH3 + zn R.T. i CHF=CHCH3 The polymerization tube, following the addition of the afor6mentioned monomers, was next sealed under vacuum and agitated in a temperature-regulated water-bath at 50' C.'for a period of 24 hours. At the end of this time, the contents of the tube were coagulated by freezin.- at liquid nitrogen temperature. The coagulated product was then removed from the tube, washed with hot water anl then dried to constant weight in vacuo at 351 C. A rubbery copolymeric product was obtained which was found, upon analysis, to comprise 2.5 mole percent 4,4dirh lorohexafluorobutene-1, and the remaining major constituent, 1,1,2-trifluoro-1,3-butadiene, being present in tertiary mercaptans. These modifiers are preferably 7 ri, an =ovnt of 97.5 mole percent. The copolymer was

2,914,514 5 obtained in an amount cortesponding to a 43% conversion. Example II Employing the procedure set forth in Example I and the same I polymerization system, the tube was charged wi,th 1.76 grams of 2,3-dichloro hexafluorobuiene-2 and 3.24 grams of 1,1,2-trifluoro-1,3-biitadiene, which comprise,d a 20/80 molar ratio. The 2,3-dichlorohexafluorobutene-2 is prepared accoreling to the procedure disclosed by Henne and Trott, 'o Joi)rnal of the American Chemical Society, volume 69, page 1820 (1947). The polymerization reaction was carried out at a temperature of 50' C. for a period of 23 hours. The re- Jr, sultant rubbery product was worked-up i n accordance with the sam& procedure as set forth in Examr)le 1. This rub@ery copolymeric product was found, upon analysis. to comprise approximately 29.5 mole percent 2,3-dichlorohexafluorobutene-2, and the remainin- majo,r constituent, 20 1,1,2-trifluoro-1,3-butadiene, being present@ in an amour@t of approximately 70.5 mole percent. The Copolymer was obtained in an amount cortesponding to a 36% conversion. Example III 25 Employing the procedure set forth in Example I and the same polymerization system, the tube was charged with 2.4 grams of 4,4-dichloroh elxafluorobutene-1 and 2.6 grams of 1,1,3-trifluoro-1,3-butadiene, which comprised a 30/70 molar ratio. 30 The 1,1,3-trifluoro-1,3-butadiene monomer was obtained by addina dibromodifluoromethane to a 2-fluoropropene to produce the adduct, CF2BrCH2CFBrCH,, which was then dehydrobrominated at about 150' C. using tri-nbutyl amine to yield CF2=CH-CF=CH2, 35 B.P. 17.5' C.-19.4' C. 2-fluoropropene was prepared by the following series of reactions: CH2CICHCICH3+KOH - CH2@--CCICHS+CHCI=CHCH3 40 (2) CH2==CCICH3+HF CHaCFCICH3 K OH: 95 percent (3) CH3CFC]CH3 CH2:==CF-CH3 ethanol The polymerization reaction was carried out at a temperature of 50' C. for a period of 24 hours. The re45 sultant rubbery copolymeric product was worked-up in ' a@cordance with the same procedure as set forth in Example I. This rubber-y product, upon analysis, was found to comprise approximately 2 mole perc.ent 4,4-dichlorohexaflubrobutene-1, and the remaining major constituent, ti o 1,1,3-trifluoro-1,3-butadiene, being present in an amount of approximately 98 mole percent. The copolymer was obtained in an amount corresponding to a 27% conversion. Example IV 55 Employing the procedure set forth in Example 1, the atalyst system was employed, except that the same c potassium stearate solution was replaced with 5 ml. of a solution prepared by dissolving I gram of the potassium salt of octanoic acid in 100 ml. of water, previously 6 0 adjusted to a pH of 11. The polymerization tube was next charged with 3.44 grams of - 4,4-dichlorohexafluorobutene-I and 1.56 grams of 1, 1,3-trifluoro-1,3-butadiene, which comprised a 50150 molar ratio. The polymerization reaction was carried out at a tem65 perature of 50' C. for a p--riod of 16 hours. The resultant rubbery copolvmeric product was worked-up in accordance with the same procedure as set forth in Example 1. This rubbery product, upon analysis, was found 70 to comprise approximately 2 mole percent 4,4-dichlorohexafluorobutene-1, and the remainin.- niajor constituent, 1,1,3-trifluoro-1,3-butadiene, being present in an amount of approximately 08 mole percent. The copolymer was obtained in an amount corresponding to a 12% conver- 75 6 Sion. The copolymeric mat6iial was ndxt cold-milled at 25' C. for a period of 10 miputes. A uniform rubbp7 sli@pt was obtained. Examp@e V Employing the procedure set forth in Example IV- and the same polymerizatioii system, the tube w@s charged with 2.44 grams of 4,4-dichlo rohexafluorobutene-1 and 2.56 grams of 1;1-difluord-2-methyl:.I,3@bu'tadiene, which comprised a 30/70 molar -ratio. The 1,1-diflu6io-2' niethyl-1,3@butadiene is p-repar6d as follows-. -benzoyl peroxide C F2Br2 + CH3CH=CHCH3 CH3 CH3 tri n-butylamine CF2BrCHCHBrOH3 C Ff-4-CH=CH2 The polymerization reaction was cam'ed out at a temperature of 50' C. for a pqriod of 16 hoiirs. The resultant rubb r e,y qopolymeric lyroduct was r6rked-up iii' . . I -1. @@i: I @ 1cordance with the same vrocedure as set f6rth i@ Ekample 1. This rubbery product, upon anal@si@. w@s f6un@d to con-lprise appro 2.5 m6le perc6iii 4,4-dichl6ro' hexafluorobutene-1, and the-Irema . ing majpjr constituent 1;1-difluoro-2-methyl-@1,3-butadiene. being present in du amount of approximately 97.5 mole percent. The copolymer was obtained in an amount coirrds onding to e. @ p 15@o' conversion.' The iaw rlibbery cdpolytieric produ-,t was cold-milled at a temperature of about 25* C.,for a period 6f 10 minutes. The uniform rubbery sheet'wag obtained. Example VI A heavy-walled glass polym,erization tube of about 20 mi. capa6iiy was fi@sh6d 'w@ @ith: nitrcigen and then charged with 5 ml. of a soluti 1 6ti :@rep@red by dissolving I gra4i of potassium persiilfate,in 100 ml. of @water. The contents of the tube w@re ihen froz6ji, and the iube was next coilnected t6 a gas-transfer system and evacu;ited at liquid nitrogen tempetature. To the fi6zen -con,tents o@,:. the tube were next added 5 ml.-Of a@ @oiutio@ pr6paied by dissolv'mg 0.75 @xanis 6f the Ctele omer aci 'd CF2CI(CFCICF2)3COOH and dissolved in ibo mi. of water, and the solution adjusted*ithpotassitimhydioxideto@ipHbf7. Thecbntehts of the tube wefe theii ftoze@. The tube wa:s then connected to a gas-transfer sy@tem and 6V@ed;ited at li4uid nitrogen tempeiat&e. To the, 'fr6zeii coni@tt@ of :the tube were added, by distillati6n, 1.76 grani@ of 2,3- dichlorohexafluorobutene-2 an:d' @3'.24 'grdmg''of 1,1 . 3@tn' fluoro-113-butadiene, '@vhich cojiiprised a 20/80 mol@r ratio. I @ - I 1. : I .1 11 . The polymerization tube was next sealed under vacuum and agitatdd@in a teriiperature-reguldted water-bath at 50' C. for a @eriod of 23-hoiirs. At the etd . of this time, the contents of the tube',,vere coagulated by frdezingatliquidnitrogentethperature. - Thd-codgu'latedproduct was then removed frdm the tube, Wa@hed With hot water and then dried to cbnstant weight in Vdciio @t 35' C. A copolymeric@ riibb@ry pr6duct was 6bt@Lined which was found, upon aha I lysis, to cbm@rise 1 in6le percent of 2,3-dichlorohexafliibrobuten&-21 and the i6maining major constituent,' 1,1,3-triflioro-1,3-buta@diene I being present in an arhount of appro--@imately 99 mole percent. I The copblymer'was obt@iiiied iii an a-mount corresponding to a 9,7o conversion. Example VII Employing the procedure set forth in Exa,mple I and the same polymerization system, the tube was charged with 2.24 grams of 2,3-dichlorohe lxafluorobutene-2 and 2.76 grams of fluoroprene (2-fluoro-1,3-butadiene),, @lihich comprised a. 20/80 molar Tatio. The polymerization reaction wa-s carried out at a temperature of 50' C. for a period of 24 hours. The resultqnt rubbery product was w rked-:up inaccordance with the same procedure as set forth. in Example 1. This

2,914,514 7 thermoplastic product w@s found, upon analysis, to comprise approximately 2.5 mole percent of 2,3-dichlorohexaffuorobutene-2, and the remaining major constituent, fluoroprene, being present in an amount of approxiniately 97.5 mole percent. The copolynier was obtained 5 in an amount corresponding to a 33% conversion. A sample of the raw copolymer was cold-milled at 25': C. for a period of 10 minutes to produce a rubbery sheeted material. This material was compression molded at a temperature of 250' F. for a period of 10 minutes. 10 After molding, the sample;retained its rubbery characteristics. A volume increase of 49% was observed in the molded sample when tested by ASTM Designation, D-470-49 T, in ASTM Type II Fuel, consisting of isooctane (60% by volume), benzene (5% by volume), 15 toluene (20,@o by volume) and xylene (15% by volume) ' The Gehman Stiffness of the molded sample of the raw copol:,mer determined according to ASTM Designation, D@1053-49 T, was as follows: 20 T2=+4.4' C.; T5=-9.10 C. Tlo=-14.7' C.; Tl(o=-29.5' C. As previously indicated, the polymeric compositions of the present invention possess highly desir@ble physical 25 and chemical properties -which make them useful for fabrication of a wide v6riety of thermoplastic articles, or for the application to various surfaces as protective coatings. In such uses, a raw elastomeric copolymer, such as is produced in accordance with the procedure set forth 30 in the above examples, is extruded or pressed into sheets at temperatures between about 250' F. and about 400' F. and at a pressure between about 500 and about 15,000 pounds per square inch for. a peri6d of about 5 to abotit 60 minutes. Thereafter, various articles can be molded 35 from preforms cut from sheets and extruded stock in the form of gaskets, diaphragms, packings, etc. In this respect, it is preferred in such applications., - that the raw copolymer also includes various vulcanizin@ agents and fluers. 40 When employed as protective coatings on any of the surfaces previously described, the raw copolymeric composition is dissolved,in any of,the aforementioned solvents and is applied to the desired surfaces, employing such apparatus as a knife-spreader ' or a doctor-blade Or 45 a reverse-roll coater. The solvent, after the copolymeric coating composition has been applied to the surface, is permitted to evaporate'. This may also be accomplished in the presence of elevated temperatures, if so desired. In many applications, it is desirable to in- r)o clude in the copolymeric coating composition, various vulcanizing agents. In the latter case, supplementary heat-treatment of the coating is required, either during the solvent-removal step or thereafter. After the solvent has been completely evaporated, the coated surface 55 is ready for use. In this respect, it should be noted that the polymeric coating or, if so desired, the protective coating may be built-up by the application of several layers, each layer being permitted to harden by solvent evaporation before the next layer is applied. Further- 60 more, if so desired, the protective coatings, or the polymeric composition, when obtained in the form of sheets, may be suitably pigmented. Other uses for the polymeric compositions of the present invention reside in the @fabrication of belting, @hose, mountings, piston and pump- r, - o valves sheet or valve disks, rolls, tubing, pressure-sensie " tiv tape for electrical insulation purposes, grommets, or as adhesives for fastening a rubber surface to a metal or another rubber surface. Since certain changes may be made in carrying olit 70 the process of the present invention in producing the desired polymeric compositions without departing from the scope of the invention, it is intended that all matter contained in the above description is to be interpreted as illustrative and not in a limiting sense. 75 8 I