Патент USA US2412960код для вставки
2,412,960 Patented Dec. 24, 1946 UNITED ‘STATES PATENT OFFICE 2,412,980 FLUID COMPOSITIONS coN'rKiNmc co POLYMERS or 'rn'ramuoaosrmnun AND ETHYLENE Kenneth L. Berry, Hockessln, Del., assignor to E. I. du Pont de Nemours & Company, Wilmington, Del., a corporation of Delaware No Drawing. Application March 19, 1945, Serial No. 583,640 2 Claims. 1 This invention relates to compositions of mat ter and more particularly to new and useful ?uid compositions comprising tetra?uoroethylene co polymers. Copolymers of tetra?uoroethylene and ethyl ene, particularly those containing a high propor tion of tetrafiuoroethylene, are characterized by (01. 260-32) , 2 ?uoroethylene/ethylene of 1:0.78 (82% tetra ?uoroethylene) and 9 parts of diisobutyl adipate was heated while stirring at 260 to 265° C. where upon a. clear solution resulted. Upon cooling the solution gelation occurred. The tetra?uoroethylene/ethylene copolymers can be obtained by polymerizing a mixture of tetrailuoroethylene and ethylene, containing at least 50% of tetra?uoroethylene under pressures bility in the common organic solvents. Such gen erally useful solvents as dimethyl succinate or 10 substantially above atmospheric pressure at a temperature in the range of 40 to 150° C. in the dimethyl phthalate will not dissolve copc‘ymers presence of water or a mixture of water and a of tetrafluoroethylene and ethylene containing a non-reactive diluent and oxygen or a peroxy cat high proportion of the former constituent. alyst. The polymer used in the foregoing ex These copolymers are also soluble only s‘ ,litly or to a, limited degree in the high boiling ketones 15 ample was prepared by the following procedure: A stainless steel high pressure reactor was flushed such as isofenchone, acetophenone, benzophe with oxygen-free nitrogen and charged with 150 none, and isophorone. Somewhat better solu parts of deoxygenated water, 50 parts of tertiary bility is obtained in a complex mixture of unsat butyl alcohol and 0.3 part of benzoyl peroxide. urated cyclic ketones boiling within the range of 250° C. to 325° C., and containing from twelve 20 The reactor was then closed and further charged with 100 parts of a mixture of tetra?uoroethyl to eighteen carbon atoms. Although the high ene and ethylene (mole ratio 1:1.28). The poly melting point and general insolubility of the co- ‘ merization was then carried out by heating the polymers of tetra?uoroethylene with ethylene is reactor at 80° C. while maintaining an internal desirable for many applications, these same prop erties make the polymers unavailable for other 25 pressure of 1600-1800 lbs/sq. in. by the periodic high melting points, non-workability and insolu uses. For many applications there are advan tages in the use of solutions rather than molten compositions to achieve the ?uid state necessary in lacquers, coating compositions, and dopes suit . injection of additional quantities of the above in dicated tetra?uoroethylene-ethylene monomer mixture. The sum of individual pressure drops during the reaction period of 19 hours was 1005 able for use in forming various objects, such as 30 lbs. The reactor was cooled, the pressure release ?lms, sheets, ribbons, bristles and ?laments. A and the copolymer discharged. ' cosity. methyl hexahydrophthalate. Dialkyl esters of saturated acyclic hydrocarbon dicarboxylic acids Solutions similar to that described in the above still further advantage in the use of solutions lies example were obtained by heating the copolymer in the ease with which they can be cast into films with the following esters: dimethyl glutarate, di or coatings of uniform thickness, which is me chanically more di?icult to accomplish with a 35 methyl adipate, diethyl adipate, dimethyl azelate, dibutyl seba-cate, dimethyl methadipate and di molten composition due to its relatively high vis This invention has as an object new and use in which the alkyl groups each contain from 1 ful compositions of matter. A further object is a method for preparing new and improved tetra 40 to 4 carbon atoms and the dicarboxylic acid con tains from 5 to 10 carbon atoms are preferred iluoroethylene copolymer compositions useful in making ?laments, bristles, ribbons, ?lms, sheets and coatings on various materials such as metal. Other objects will appear hereinafter. since in general they yield solutions having the highest polymer content. This invention is applicable to and is usually The above objects are accomplished by dissolv 46 practiced with copolymers consisting essentially of the reaction product of 50 to 85% tetra?uoro ing a tetra?uoroethylene/ethylene copolymer ethylene and 50 to 15% ethylene. containing from 50 to 85% of tetra?uoroethylene The polymer solution can be conveniently pre in a neutral ester of a saturated dicarboxylic acid pared by agitating the polymer with the solvent containing at least 5 carbon atoms, such ester being free of multiple carbon to carbon linkages 50 at temperatures ranging from approximately 200“ up to the boiling point of the solvent. Solu and containing from '7 to 18 carbon atoms. tions prepared in this manner will gel 'upon cool The following example is further illustrative of ing to temperatures somewhat below that used the practice of the invention: _ A mixture of 1 part of tetra?uoroethylene/ in the preparation of the solution. The tem perature of gelation is dependent somewhat upon ethylene copolymer having a mole ratio oi tetra aéraceo the solvent, the concentration of the solution and the viscosity of the polymer. Thus, highly con= centrated solutions, e. g. about 40% solids, usu ally gel at higher temperatures than do solutions and porous objects such as fabrics, paper, regen erated cellulose and wood. As many apparently widely di?'erent embodi ments of this invention may be made without de parting iromthe spirit and scope thereof, it is to _ Similarly solutions of polymer containing high be understood that I do not limit myself to the viscosity polymer gel at higher temperatures than speci?c embodiments thereof except as de?ned in do solutions containing lower viscosity polymers. the appended claims. In general, the solubility of the polymer is de» I claim: creased and the gel temperature of polymer sclu= 10 1. A composition oi’ matter comprising a solu tions is raised as the percentage of tetra?uorm ‘ ' tion in organic solvent of a copoiymer of tetra ethylene in the polymer is increased. containing > lower concentration of ; polymer. . By employing the neutral esters of dicarboxylic ?uoroethylene and ethylene containing from 50% acids of the type hereinbefore described, solu to_85% tetrajfiuoroethylene, said solvent being a tion ranges from 1 up to approximately 40%. The present process is of particular value in that the solutions can be obtained with copolymers free of multiple carbon to carbon linkages and containing from 7 to 18 carbon atoms. ester of a saturated dicarboxylic acid con tions of tetra?uoroethylene/ethylene copolymers 15 neutral taining at least 5 carbon atoms, said ester being can be obtained in which the polymer concentra= 2. A process for obtaininga solution in an or~ ganic solvent of a copolymer of tetra?uoroethyl made from tetraiiuoroethylene and ethylene 20 one and ethylene containing from 50% to 85% alone, and without including in the polymer re l~tetra?uoroethylene, said process comprising heat» action mixture any modifying agent designed. to ing said polymer with a neutral ester at a tem improve solubility. 1 perature of from 200° C. to that of the boiling The new solutions of tetra?uoroethylene/eth point of said ester, said ester being an ester of a ylene copolymers disclosed herein are advanta 25 saturated dicarboxylic acid containing at least 5 geously used in a number of applications, for ex carbon atoms, said ester being free of multiple ample for the preparation of the polymer disper carbon to carbon linkages and containing from sions, for coating metal objects such as wire, for 7 to 18 carbon atoms. ' casting ?lms and iorimpregnating glass ?bers ’ - L. BERRY.