FLUORINATED ESTER MELT ADDITIVES FOR THERMOPLASTIC FIBERS

Abstract: A composition having repellency to low surface tension fluids comprising a material prepared by forming a mixture of a polymer selected from the group consisting of polyolefin, polyamide, polyester, polyacrylate, and blends and copolymers thereof, and a fluorochemical compound comprising a fluorocarbon/hydrocarbon ester of the formulae: Rf-O-C(O)-R1 or Rf-C(O)-O-R1 wherein Rf is selected from the group consisting of: 1) F(CF2)x-(CH2)m wherein x is from about 4 to about 20 and m is from about 0 to about 6; and 2) F(CF2)x-SO2N(R2)-R3 where x is a positive integer from about 4 to about 20, R2 is an alkyl radical of from about 1 to about 4 carbon atoms, R3 is an alkylene radical of from about 1 to about 12 carbon atoms; and R1 is an aliphatic hydrocarbon having from about 12 to about 76 carbon atoms; and provided that said fluorochemical compound is other than perfluoroalkylethyl stearate; and melt extruding the mixture.

Description: TITLE FLUORINATED ESTER MELT ADDITIVES FOR THERMOPLASTIC FIBERS FIELD OF THE INVENTION This invention relates to a process for imparting superior repellency of low surface tension fluids to thermoplastic polymers, in particular fibers, fabrics, nonwovens, films and molded articles by the addition of certain fluorinated esters to the polymer melt. BACKGROUND OF THE INVENTION Thermoplastic polymer fibers are frequently treated with fiuorochemical compounds m order to affect the surface characteristics of the fiber, for example to improve water repellency or to impart stain or dry soil resistance Most frequently, fiuorochemical dispersions are applied topically to the fabrics made from these fibers by spraying, padding or foaming, followed by a drying step to remove water. For example, a method is known for obtaining dry soil resistance and nonflame propagating characteristics m a textile fiber by applying topically aqueous dispersions of a variety of fluorinated esters derived from perfluoroalkyl aliphatic alcohols of the formula C n F 2n+ {CH2) m 0H where n is from about 3 to 14 and m is 1 to 3 , together with mono- or polycarboxylic acids which contain from 3 to 30 carbons and can contain other substituents. The fluorinated esters include, among others, a perfluoroalkylethyl stearate corresponding to "ZONYL" FTS, as well as perfluoroalkylethyl diesters made from dodecanedioic acid or tridecanedioic ac d. It is well recognized that the process of manufacturing thermoplastic polymeric fibers and fabrics could be simplified and significant capital investment could be eliminated if the topical application were replaced by incorporating a fiuorochemical additive into the polymer melt prior to the extrusion of the fiber. The difficulty has been m finding suitably effective fiuorochemical additives. Thermoplastic polymers include, among others, polyolefins, polyesters, polyamides and polyacrylates. Polyolefins, and m particular polypropylene, are frequently used for disposable nonwoven protective garments, particularly m the medical/surgical field, m part because of a polyolefin's inherent water-repellency. However, po.yolefms are not inherently good repellents for other lower surface tension fluids frequently encountered in the medical field such as blood and isopropyl alcohol . To get around t his deficiency, fiuorochemical dispersions are applied topically to these fabrics . The requirements of an additive suitable for incorporating into a polyolefin melt include, besides the ability to repel low surface tension fluids at a low concentration of the additive, a satisfactory thermal stability and low volatility to withstand processing conditions. Preferably the compound will migrate to the surface of the fiber so as to minimize the amount of additive needed for adequate repellency While this migration can often be enhanced by post-extrusion heating of the fiber, it is more preferable for the migration to occur without the need for this heating step. This requirement for mobility m the polymeric fiber m turn tends to limit the size of the fiuorochemical molecule, and effectively eliminates from consideration high molecular weight polymeric fiuorochemical additives . The general concept of incorporating fiuorochemical additives into a polyolefin fiber melt is known, but the difficulty in finding suitable effective additives has limited the application of this concept Many of the past efforts to evaluate such fiuorochemical additives have been aimed at improving other properties of the polyolefin, and do not tea:h methods of its improving repellency to low surface tsnsion fluids . Nonwoven composite structures are known consisting m part of two or more melt-extruded nonwoven layers, at least one of which includes an additive which imparts to the surface at least one characteristic different than the surface characteristics of the polymer alone as a result of preferential migration of the additive to the surface without the need for post-formation treatment of any kind. Examples of the additive-including layer include polypropylene modified by commercially available fiuorochemical additives, including "ZONYL" FTS defined above. U.S. Patent 5,178,931 and U.S. Patent 5,178,932 disclose specific nonwoven lammiferous and composite structures respectively, consisting m part of three melt- extruded nonwoven layers, the second of which includes an additive which imparts alcohol repellency as a result of preferential migration of the additive to the surface without the need for post-formation treatment of any kind, and where at least one of the first and third layers has been treated by topical application of an agent to change its characteristics m some way. Examples of the additive-including second layer include commercially available fluorochemicals, including "ZONYL" FTS. Soil resistant polymeric compositions are known which are prepared by melt extrusion with a nonpolymeric fiuorochemical dispersed throughout the polymer. The polymers used include polypropylene, polyethylene, polyamide and polyester, and the fiuorochemical used is a perfluoroalkylstearate, in particular "ZONYL" FTS. In addition, a polymeric composition is known comprising a mixture of a polymer selected from the group of polypropylene, polyethylene, polyamide and polyester with a fiuorochemical comprising a fluorinated oleophobic, hydrophobic alkyl group attached to a nonfluoπnated oleophilic alkyl, aryl, aralkyl or alkaryl moiety optionally through a linking moiety, which can be melt extruded as a mixture. A more specific description of the above fiuorochemical is not disclosed, but among the many compounds which are applicable are esters where the oleophilic organic group contains from 2 to 35 carbon atoms. Examples of such are "ZONYL" FTS or a product made by transesterifying "ZONYL" BA with methyl stearate and methyl palmitate . An automotive coating film is known containing an organic solvent-soluble waxy hydrocarbon which possesses a fluorine-containing organic group. This component is a product obtained by esterifymg and coupling a high molecular weight alcohol with a carboxylic acid which possesses a fluorine- containing group or a product obtained by esterifymg and coupling a high molecular weight fatty acid and an airohol which possesses a fluorine-containing group As examples of high molecular weight alcohols included are those witn average carbon chain lengths with up to 50 carbons As examples of high molecular weight fatty acids included are those .vith carbon chain lengths of up to 31 carbons (mellisic acid) . The products were tested only as a waxing agent for automobiles. Japanese Patent Application 3-41160 to Kao Corp. teaches a thermoplastic resin composition containing a perfluoroalkyl group-containing long chain fatty ester of the formula Rf-Rχ-OCO-R2 where Rf is a perfluoroalkyl group with 5 to 16 carbons, R-*_ is an alkylene group with 1 to 4 carbons, and R2 is an unsaturated alkyl group or a saturated alkyl group with 21 to 50 carbons One example reacts CgF 17 C 2 H 4 θH with C 27 H5 5 COOH to produce the ester The resins included polyethylene and polypropylene Benefits of the additive were shown by the contact angle of water with molded articles of the resin. No tests are reported on the repellency to low surface tension fluids of the resulting polymers In summary, while the prior art discloses numerous examples of polyolefin fibers containing a fiuorochemical additive incorporated at the melt stage to alter the surface characteristics of the extruded flbei , much of this was aimed at soiling and staining resistance, water repellency or other purposes Those references which were aimed at imparting alcohol repellency to polyolefin fabrics employ "ZONYL" FTS. A need exists to achieve superior repellency to low surface tension fluids and superior product efficiency. The fluorinated compounds of the present invention meet this need. SUMMARY OF THE INVENTION The present invention comprises a composition and a process for imparting repellency of low surface tension fluids to thermoplastic polymer articles. The composition having repellency to low surface tension fluids of the present invention comprises a material prepared by: forming a mixture of a polymer selected from the group consisting of polyolefin, polyamide, polyester, polyacrylate, and blends and copolymers thereof, and a fiuorochemical compound comprising a fluorocarbon/hydrocarbon ester of the formulae : Rf-O-C(O) -R-i or R f -C(0)-0-R 1 wherein Rf is selected from the group consisting of 1) F (CF2) " (CH 2 ) r n wherein x is from about 4 to about 20 and m is from about 0 to about 6, and 2) F (CF 2 ) x -S0 N(R 2 ) -R3 wherein x is a positive integer from about 4 to about 20, R 2 is an alkyl radical of from 1 to about 4 carbon atoms, and R3 is an alkylene radical of from 1 to about 12 carbon atoms and R- j _ is an aliphatic hydrocarbon of from about 12 to about 76 carbon atoms; provided that said fiuorochemical compound is other than perfluoroalkylethyl stearate; and melt extruding the mixture . The present invention further comprises the above composition in the form of a filament, fiber, nonwoven fabric or web, film or molded article. The present invention further comprises a process for imparting repellency of low surface tension fluids to a thermoplastic polymer article comprising forming a mixture prior to article formation of a polymer and an effective amount of a fiuorochemical compound comprising a fluorocarbon/hydrocarbon ester as defined above and melt extruding the mixture. Such articles include filaments, fibers, nonwoven webs or fabrics, films or molded articles. DETAILED DESCRIPTION OF THE INVENTION Superior repellency to low surface tension fluids is imparted to thermoplastic polymer articles, in particular fibers, fabrics, filaments, nonwovens, films, and molded articles, by the addition of certain monomeric fluorinated ester compounds to a polymer prior to article formation and melt extruding the resulting mixture. This process is used either with or without post-extrusion heating of the article to promote movement of the additive to the article surface, since the ester compounds of this invention tend by their nature to concentrate on the surface. The term "low surface tension fluids" is used herein to mean fluids having a surface tension of less than 50 dynes/cm (50 x 10 "7 newton metre) . Examples of such fluids include alcohols, blood, and certain body fluids. The composition of the present invention comprises a material prepared by melt extruding a mixture of a polymer selected from the group consisting of polyolefin, polyamide, polyester, polyacrylate, and blends and copolymers thereof, and a fiuorochemical compound, other than perfluoroalkylethyl stearate, comprising a fluorocarbon/hydrocarbon ester of the formulae : Rf-0-C(0)-R-ι or Rf-C{0)-0-R 1 wherein Rf in the above formulas is F (CF ) • - (CH 2 ) m wherein x has a preferred average value of about 7 to 10 and a range of about 4 to about 20 and m has a value of 0 to 6. Especially preferred for Rf is a composition wherein the chain length distribution is as follows: x=6 or less 0-10% by weight x=8 45-75% by weight x=10 20-40% by weight x=12 1-20% by weight x=14 or greater 0-5% by weight. This composition range, when m=2, and x has an average value of about 9, is hereinafter referred to as Telomer BN. This definition of Rf in the formula Rf-OH is referred to as Telomer BN alcohol . Alternatively Rf is a fluorinated sulfonamide of the structure F (CF 2 ) x -S0 2 N (R 2 ) -R3 wherein x is a positive integer from about 4 to about 20, preferably 4 to 10 inclusive, R 2 is an alkyl radical having from 1 to 4 carbon atoms, and R3 is an alkylene radical having from 1 to 12 carbon atoms. Preferably R 2 is CH 3 and R 3 is -CH 2 CH 2 -, -(CH 2 ) 3 -, or -<CH 2 ) 4 -. The fluoroalkyl portion of the alternative Rf structure is a fluorinated, preferably saturated, monovalent, non-aromatic, aliphatic radical of at least three fully fluorinated connected carbon atoms m a chain. The chain m the radical is straight, branched, or, if sufficiently large, cyclic and is optionally interrupted by divalent oxygen atoms, hexavalent sulfur atoms, or trivalent nitrogen atoms bonded only to carbon atoms A fully fluorinated aliphatic radical is preferred, but hydrogen or chlorine atoms are optionally present as substituents m the radical provided that not more than one atom of either is present m the radical for every two carbon atoms . R^ is an aliphatic hydrocarbon with a carbon chain length of about 12 to about 76 carbons, preferably from about 24 to about 50 carbons. Alcohols corresponding to are commercially available from Petrolite Corporation, Polymer Division Headquarters, 6910 E. 14th Street, Tulsa, Oklahoma, USA 74112, under the trademark "UNILIN". "UNILIN" alcohols are fully saturated long chain linear alcohols The approximate R 1 ranges of "UNILIN" 350, 425, 550 and 700 are 12 to 50, 14 to 58, 16 to 56 and 14 to 66, respectively. The average chain lengths for "UNILIN" 350, 425, 550 and 700 are about 24, 32, 40 and 48, respectively. These are preferred for use m the present invention Acids corresponding to R-*_- COOH are commercially available from Petrolite Corporation, Polymers Division Headquarters, 6910 E. 14th Street, Tulsa, Oklahoma, 74112, under the trademark "UNICID" . The range of average chain lengths for "UNICID" 350, 425, 550 and 700 are 24-29, 29-37, 37-45 and 40-48, respectively. These are preferred for use in the present invention. More particularly the "UNILIN" and "UNICID" carbon chain lengths are as noted m Table A. TABLE A GC DATA** UNILIN Lit . Avσ % Alcohol Ranqe Average 350 C24-26 C12-46 C24-26 425 C30-32 85.0 C14-58 C30-32 550 C40-42 79.5 C16-56 C38 700 C48-50 83.6 C14-66 C50 cc DATA** UNICID Lit, Avg-* % Acid Ranσe Averag 350 C24-29 79.0 C12-50 C28-30 425 C29-37 550 C37-45 80.0 C16-62 C42-44 700 C40-48 C16-76 * Literature average **Gas chromatography data There are various methods by which the above compounds can be prepared, and the inventive process is not limited to a particular method of preparation. For example, the above compounds are conveniently made by reacting an appropriate fatty alcohol with the appropriate fluorocarbon acid to form an acid ester, or by reacting an appropriate fatty acid with the appropriate fluorocarbon alcohol. Other compounds in these groups are readily made by those skilled in the art by following similar processes. The esters useful in this invention are mixed with thermoplastic polymers by adding them to pelletized, granular, powdered or other appropriate forms of the polymers and rolling, agitating or compounding the mixture to achieve a uniform mixture which is then melt extruded. Alternatively the esters are added to a polymer melt to form a mixture which is then melt extruded. The thermoplastic polymer is a polyolefin, polyester, polyamide, or polyacrylate. The thermoplastic polymer preferably is a polyolefin, mixture or blend of one or more polyolefins, a polyolefin copolymer, mixture of polyolefin copolymers, or a mixture of at least one polyolefin and at least one polyolefin copolymer. The thermoplastic polymer is more preferably a polyolefin polymer or copolymer wherein the polymer unit or copolymer unit is ethylene, propylene or butylene or mixtures thereof. Thus the polyolefin is preferably polypropylene, polyethylene, polybutylene or a blend or copolymer thereof The amount of the fluorinated compound to be added to the thermoplastic polymer is preferably between 0.1 and about 5% by weight of the polymer Amounts above this range can be used but are unnecessarily expensive in relation to the benefit received. The blend is then melted and extruded into fibers, filaments, nonwoven webs or fabrics, films, or molded articles using known methods The fluorine content of the fiber, filament, nonwoven fabric or web prepared therefrom, film or molded article is from about 200 ug/g to about 25,000 ug/g Extrusion is used to form various types of nonwovens In particular, extrusion is used to form a melt blown nonwoven web of continuous and randomly deposited microfibers having an average diameter of approximately 0.1 to 10 microns, preferably m the range of about 3 to 5 microns The melt extrusion is carried out through a die at a resin flow rate of at least 0.1 to 5 grams per minute per hole, with the microfibers being randomly deposited on a moving support to form the web In the above melt blowing process, polymer and a compound of the present invention are fed into an extruder where it is melted and passed through a die containing a row of tiny orifices As the polymer emerges from the die, it is contacted by two converging, high-velocity hot air streams, which attenuate the polymer into a blast of fine, discontinuous fibers of 0.1 to 10 microns m diameter The useful polymer throughputs or flow rates range from 0.1 to 5 grams per minute per hole. Typical gas flow rates range from 2.5 to 100 pounds per square inch (1 72 x 10 5 to 6.89 x 10 5 Pa) per minute of gas outlet area. The air temperature ranges from about 400°F (204°C) to 750°F (399°C) Cooling air then quenches the fibers, and they are deposited as a random, entangled web on a moving screen which is placed 6 to 12 inches (15.2 to 30.5 cm) m front of the blast of fibers Melt blowing processes are described m further detail in articles by V A Wente, "Superfine Thermoplastic Fibers", Industrial and Engineering Chemistry, Vol. 48(8) , pp 1342-1346 (1956) ; and by R. R. Buntin and D. T. Lohkamp, "Melt Blowing - A One-step Web Process for New Nonwoven Products", Journal of the Technical Association of the Pulp and Paper Industry, Vol. 56(4) , pp 74-77 (1973) ; as well as in U.S. Patent 3,972,759 to R. R. Buntin. The disclosures of these documents are hereby incorporated by reference. The unique properties of a melt blown nonwoven web comprised of a random array of fine, entangled fibers include very large surface areas, very small pore sizes, moderate strength and light weight fabric structure. These properties make the nonwoven webs particularly suitable for such applications as medical fabrics where barrier properties as well as breathability and drape are important. Extrusion is also used to form polymeric films. In film applications, a film forming polymer is simultaneously melted and mixed as it is conveyed through the extruder by a rotating screw or screws and then is forced out through a slot or flat die, for example, where the film is quenched by a variety of techniques known to those skilled in the art. The films optionally are oriented prior to quenching by drawing or stretching the film at elevated temperatures. Molded articles are produced by pressing or by injecting molten polymer from a melt extruder as described above into a mold where the polymer solidifies. Typical melt forming techniques include injection molding, blow molding, compression molding and extrusion, and are well known to those skilled in the art. The molded article is then ejected from the mold and optionally heat-treated to effect migration of the polymer additives to the surface of the article. An optional heating or annealing step can be conducted but is not required. The polymer melt or extruded fiber, filament, nonwoven web or fabric, film, or molded article is heated to a temperature of from about 25°C to about 150°C. The heating in some cases may improve the effectiveness of the fiuorochemical additive in lmpai'ting alcohol repellency. The compositions of the present invention are useful in various fibers, filaments, nonwoven webs or fabrics, films and molded articles. Examples include fibers for use in fabrics and carpets, nonwoven fabrics used in protective garments used in the medical/surgical field, and molded plastic articles of many types. The process of the present invention is useful for imparting repellency of low surface tension fluids to various thermoplastic polymer articles such as filaments, fibers, nonwoven webs or fabrics, films and molded articles. Example 1 Synthesis of Rf-O-C(O) -R-*_, wherein Rf is an aliphatic fluorocarbon radical of formula F (CF 2 ) x (CH 2 ) m where the average value of x is 9, m=2, and wherein R-]_ has an average value of 32 carbon atoms. A 250-mL flask was fitted with a mechanical stirrer, temperature control device, Dean-Stark trap, water condenser, nitrogen gas inlet tube and heating mantle. Into the flask were charged 79. lg (0.15 mole) F (CF 2 ) n CH 2 CH 2 OH where n=6-18, avg. n=9 and 89.4g (0.15 mole) "UNICID" 425 Acid (C 29 -C 37 aliphatic acid from Petrolite Corporation, 6910 E. 14th Street, Tulsa, Oklahoma, USA, 74112, acid no. = 94 mgKOH/g) . The mixture was heated and held at 120°C. When the mixture was homogeneous, 0.3g phosphorous acid and 0.12g boric acid were added. The temperature was raised to 140-145°C and held for approximately 87 hours with continuous removal of water. When a gas chromatographic analysis of the reaction mixture indicated that all telomer BN alcohol had reacted, the mixture was cooled slightly and discharged yielding 44.65g (87%) of product. Infrared analysis confirmed the above structure. The product was a tan solid and melted at 66.65°C by Differential Scanning Calorimetry (DSC) . The percent fluorine found by analysis was 32.4 % compared to a theoretical analysis of 33.4%. Examples 2 - 15 These examples were prepared using the procedure of Example 1 Table 2 lists the acid from which the fluoroester was prepared and the fluorocarbon distribution of the alcohol All examples were used to prepare melt blown nonwoven webs and tested for alcohol repellency as described m Example 16 : Example 16 Step 1 : Preparation of the polymer blend Uniform mixtures of the fiuorochemical additives produced m Examples 1-16 together with a polyolefin were prepared by combining them and rolling the mixture for about 24 hours. Comparative examples A-D used the monoester "ZONYL' FTS and were prepared in a similar manner In particular, for the compound of Example 4, a uniform mixture of 16. lg (1.2 weight %) of finely ground compound of Example 4, and l,349g Escorene PD3746G (Exxon Chemical Americas, P.O. Box 3273, Houston, Texas 77001) polypropylene resm having a melt flow rate of approximately 1000 was prepared by rolling the mixture for 24 hours. The fluorine concentration m the mixture was calculated to be 3300μg/g fluorine. Actual fluorine concentration m the nonwoven web was 2930μg/g fluorine. Comparative examples, designated A-D were prepared ir the same manner. Step 2 : Melt blown web formation Melt blown nonwoven webs were prepared from the above mixtures using a 6-mch (15 cm) melt blowing pilot unit at a polymer feed rate of about 0.4 gram/minute/hole . The polymer blends were fed into the extruder having three barrel zones eit temperatures ranging from 175°C to 250°C. The temperature at the die was from 200°C to 260°C and the air temperature at the die varied from 200°C to 270°C. The die tip gap was 0.060 inches (0.15 cm) and the primary air pressure was 2 6 psi (17.9 x 10 3 Pa) . The webs were formed on a drum coated with "TEFLON" at an output of 0.4gram/hole/mmute and collected on a take-up roll operating at 30 feet/minute (914 cm/minute) which resulted in the fabrics having a basis weight of 1.0 oz. /square yard (34 gm/square meter) . Step 3. Repellency testing The water repellent properties of the melt blown webs were measured using an isopropyl alcohol/water test and are expressed in terms of percent isopropyl alcohol rating. Webs that resisted penetration of a 100% isopropyl alcohol/0% water solution (lowest surface tension fluid) after 1-2 minutes were given the highest rating of 100. Webs that are only resistant to a 100% water/0% isopropyl alcohol solution after 1-2 minutes are given the lowest rating of 0. Table 1 lists ratings that correspond to other isopropyl alcohol/water mixtures used m this test. The rating for a given fabric corresponds to the lowest surface tension fluid (greatest % isopropyl alcohol/water solution) that does not wet the fabric after 1-2 minutes. Table 1 Percent Isopropyl Alcohol Ratings Rati .ng %Isopropyl alcohol/%water (vol/vol 100 100/0 90 90/10 80 80/20 70 70/30 60 60/40 50 50/50 40 40/60 30 30/70 20 20/80 To evaluate m-process repellency, the webs were rated immediately after exiting the melt blown line and then after two days and after about one week. Table 2 summarizes the percent isopropyl alcohol data for the polypropylene melt blown webs containing the esters of Examples 1-15 and the comparison examples A-D containing "ZONYL" FTS available from E. I. du Pont de Nemours and Company, Wilmington, Delaware, at different fluorine concentration levels. Also included in the table is a polypropylene control sample (PP Control) . The results in Table 2 showed the clear advantage of the inventive composition over the comparative and control samples, the advantages showing up immediately and over time. A related advantage for the inventive composition is better performance at lower levels of fiuorochemical additive. Table 2 Isopropyl Alcohol Repellency of Polypropylene Melt Blown Webs μg/g Fluorine Isopropyl alcohol repellency Example Dist- 1 Acid Targe /Actual As made 2 days 1 week Heated 2 1 BN "UNICID" 350 1500/1480 40 -- 90 100 30 a 2 BL "UNICID" 350 1700/1480 40 -- 80 30 a 3 BN "UNICID" 425 3300/2930 90 90-100 90- 100 90 b 4 BN "UNICID" 425 3300/3120 40 80 90 90 b 5 BN "UNICID" 550 3300/2720 100 100 100 100 b 6 BN "UNICID" 550 3300/2790 40 60 90 90 b 7 BN "UNICID" 550 1980/1910 70 80 100 a 8 BL "UNICID" 550 1980/1570 60 -- -- 92 9 BN "UNICID" 700 3300/3210 100 100 10C ) 100 c 10 BN "UNICID" 700 4500/2760 40 40 100 b 11 BN "UNICID" 700 1980/1780 50-60 80 90 70 12 BN Stearic 3300/2940 70 80-90 90- 100 80 b tn 13 BN Stearic 3300/3510 30 60 80 70 b 14 M "UNICID" 550 1980/1550 40 50 80 50 15 M Stearic 1980/1610 30 40 30 a A B Stearic 3300/3050 70 80-90 90 80 b B B Stearic 3300/3010 30 60 80 60-70 b C B Stearic 2875/2426 40 80 80 80 b D B Stearic 2423/1910 30 70 70- 80 80-90 b Control 20 20 20 Fluoro Annealing process a Web was annealed at 176F (80°C) for 15 seconds shortly after processing b Web was annealed at 140F (60°C) for 25 hours about one week after processing c Web was annealed at 180F (82 20°C) for 1 minute shortly after processing

Claims: What is claimed is: 1. A composition having repellency to low surface tension fluids comprising a material prepared by: forming a mixture of a polymer selected from the group consisting of polyolefin, polyamide, polyester, polyacrylate, and blends and copolymers thereof, and a fiuorochemical compound comprising a fluorocarbon/hydrocarbon ester of the formulae: R f -0-C(0) -R 1 or R f -C(0) -0-R 1 wherein Rf is selected from the group consisting of : 1) F (CF2) x - ( H2) m wherein x is from about 4 to about 20 and m is from about 0 to about 6 ; and 2) F (CF2) X -SO2 (R2) -R3 wherein x is a positive integer from about 4 to about 20, R2 is an alkyl radical of from 1 to about 4 carbon atoms, and R3 is an alkylene radical of from 1 to about 12 carbon atoms; and R- ] _ is an aliphatic hydrocarbon having from about 12 to about 76 carbon atoms; provided that said fiuorochemical compound is other than perfluoroalkyethyl stearate; and melt extruding the mixture. 2. The composition of Claim 1 wherein the polymer is selected from the group consisting of polyolefin, mixture of polyolefins, polyolefin copolymer, mixture of polyolefin copolymers, and mixture of at least one polyolefin and at least one polyolefin copolymer. 3. The composition of Claim 1 wherein Rf is F (CF2) x (CH2) t n wherein x is from about 8 to about 12 and is an average of about 9, and m is 2. 4. The composition of Claim 1 wherein the fiuorochemical is present in an amount of from about 0.1% to about 5% by weight of the polymer. 5. The composition of Claim 1 having a fluorine content of from about 200 ug/g to about 25,000 ug/g. 6. The composition of Claim 1 in a form selected from the group consisting of an extruded filament, fiber, nonwoven web, nonwoven fabric, film and molded article. 7. A process for imparting repellency of low surface tension fluids to a thermoplastic polymer article comprising forming a mixture prior to article formation of a polymer and an effective amount of a fiuorochemical compound comprising a fluorocarbon/hydrocarbon ester of the formulae: R f -0-C(0)-R 1 or Rf-CCC -O-R- L wherein Rf is selected from the group consisting of: 1) F (CF 2 ) x - (CH 2 ) m wherein x is from about 4 to about 20 and m is from about 0 to about 6; and 2) F (CF2) χ -S02N(R ) -R3 wherein x is a positive integer from about 4 to about 20, R2 is an alkyl radical of from about 1 to about 4 carbon atoms, and R3 is an alkylene radical of from about 1 to about 12 carbon atoms; and R ] _ is an aliphatic hydrocarbon having from about 12 to about 76 carbon atoms; provided that said fiuorochemical compound is other than perfluoroalkylethyl stearate; and melt extruding the mixture. 8. The process of Claim 7 further comprising heating the formed article to a temperature of from about 25°C to about 150°C. 9. The process of Claim 7 wherein the amount of the fiuorochemical compound is from about 0.1% to about 5% by weight of the polymer. 10. The process of Claim 7 wherein the article after formation has a fluorine content of from about 200 ug/g to about 25,000 ug/g.

Inventors: GREENWOOD EDWARD JAMES, LISS THEODOR ARTHUR, RAIFORD KIMBERLY GHEYSEN, GREENWOOD, EDWARD, JAMES, LISS, THEODOR, ARTHUR, RAIFORD, KIMBERLY, GHEYSEN
Applicants: DU PONT, E.I. DU PONT DE NEMOURS AND COMPANY
Application year: 1996
Main classification: C08K5
IPC codes: C08K5, C08L23, C08L33, C08L67, C08L77, C08L101, D01F1, D01F6, D04H1