US3839312A - Polypropylene fibers having improved soil and stain repellency - Google Patents

Abstract

The soil and stain repellency of extruded filaments of a synthetic resin can be improved by incorporating in the resin a small amount, about 1 percent, of an amphipathic compound having from one to four fluoroalkyl groups pendent from an organic radical. The repellency is provided by the fluoroalkyl groups, which tend to be concentrated at the surface of the fiber.

Description

United States Patent Oxenrider et al. Oct. 1, 1974 POLYPROPYLENE FIBERS HAVING [52] US. Cl. 260/93.7, 260/75 H, 260/78 S, IMPROVED SOIL AND STAIN 260/88.7 B, 260/94.9 GD R LL [51] Int. Cl. C08f 29/02 [75] Inventors: Bryce C Oxenride-r, Florham Park; [58] Field of Search 260/93.7, 94.9 GD 3 ll Woolf Momstown both of Primary ExaminerMelvin Goldstein Attorney, Agent, or Firm-Arthur J. Plantamura [73] Assignee: Allied Chemical Corporation, New

York, NY. [57] ABSTRACT [22] Filed. July 25 1973 The soil and stain repellency of extruded filaments of a synthetic resin can be improved by incorporating in PP 382,622 the resin a small amount, about 1 percent, of an am- Related Application Data phipathic compound having from one to four fluoroal- [62] Division of Ser. No. 205,424, Dec. 6, 1971, Pat. No kyl groups pendent from an Orgamc radical The re- 3,767,625, which is a division of Ser. No. 867,368, Oct. 17, 1969, Pat. No. 3,646,153.

pellency is provided by the fluoroalkyl groups, which tend to be concentrated at the surface of the fiber,

3 Claims, No Drawings POLYPROPYLENE FIBERS HAVING IMPROVED SOIL AND STAIN REPELLENCY This is a division of application Ser. No. 205,424, filed Dec. 6, 1971 which in turn is a division of application Ser. No. 867,368, filed Oct. 17, 1969 now U.S. Pat. Nos. 3,767,625 and 3,646,153 respectively.

BACKGROUND OF THE INVENTION This invention relates to synthetic fibers having im proved soil and stain repellency.

It is desirable to impart soil and stain repellency to fabrics used in apparel, upholstery, draperies and similar applications. The present method used to impart soil and stain repellency to fabrics involves coating the fabric with an oil and water repellent compound. The coating is applied using common textile finishing techniques, such as treating the fabric with a padding bath of a solution or aqueous dispersion of the compound or spraying the surface of the fabric with the compound. In any case, the operation represents a separate step which must be performed upon a fabric after it has been dyed or printed. In addition, a subsequent curing step is normally required to set the coating. The coating is present on the fabric as a distinct phase which is subject to removal. Soil which penetrates the coating is not easily removed by laundering or dry cleaning because the soil becomes trapped beneath the coating.

Another drawback of the present method is the difficulty inherent therein of applying a uniform coating to the fabric. The coating tends to be distributed unevenly on the fabric and to form globules thereon.

SUMMARY OF THE INVENTION We have found that oil and stain repellency can be imparted to extruded filaments of fiber-forming thermoplastic resins directly by adding certain fluorine containing compounds to the resin from which the fibers are prepared. Fibers prepared from the modified resin have improved soil and stain repellency and exhibit better stain release during laundering and dry cleaning. The fluorocompound additives of this invention reduce the surface energy of the fiber, but otherwise do not affect the mechanical (e.g. tensile) properties of the fiber. Consequently, the fibers can be woven into fabrics in the same manner as unmodified fibers, and in addition, can be used to prepare other textile products, such as carpets, having improved soil and stain repellency. A principal advantage of this invention is that oil and stain repellency can be readily imparted directly to the fiber by the fiber manufacturer, thereby eliminating the need for the manufacturer of the ultimate textile product to apply a repellent coating to the fabric.

The additive is added to the resin in an amount ranging from about 0.1 to about 2 percent, preferably about 0.5 to 1.5 percent, based on the weight of the resin.

This small amount of additive causes a substantial lowering ofthe surface energy of the fiber, which is a direct measure of the ability of the fiber to repel oil and water borne soil and stain. For example, a fiber of unmodified nylon-6 normally has a surface energy of about 46 dynes/cm, whereas a fiber of nylon-6 containing 1 percent of an additive of this invention has a surface energy which is only slightly more than that of the additive itself (the additives have surface energies ranging from about l0 to 20 dynes/cm.). To explain this phenomenon, it is theorized that the additive migrates to the surface of the fiber as the fiber is extruded to form a boundary layer between the rest of the fiber system and that which contacts the fiber. This boundary layer is not permanently removed by scouring, laundering, dry cleaning or dyeing, which indicates that it is stable to use conditions.

In spite of this boundary layer, the fiber can be dyed just like the unmodified fiber, which is surprising in view of the repellent nature of the layer.

The fluorocompound additives of this invention are characterized in their molecular structure in having from one to four fluoroalkyl groups, which provide the repellency, pendent from an organic radical which serves to make the additive dispersible in the resin. Hence, the additive is amphipathic in that one segment of the molecule has an affinity for the resin substrate while the remainder of the molecule, containing the perfluoroalkyl groups, is essentially repellent in nature.

In referring to the relationship between the additive and the resin, the terms dispersed and dispersible are used herein to indicate that the additive and the resin together form a macroscopically homogeneous single phase which behaves substantially like the resin alone in processing and in forming filaments. As is indicated in Examples 1-4, the additive can be present in the resin as (l) a solution of the additive in the resin, (2) a random distribution of additive particles throughout the resin, or (3) a concentration of additive particles near the surface of the resin.

The fluoroalkyl group is the more critical portion of the molecule and has the formula:

wherein m is an integer from 1 to 16,n is an integer not greater than m from 0 to 8, with the sum of m plus n being from 1 to 20, and Y is selected from the group consisting of F;,C and radicals having the formula wherein R and R are fluorine or perfluoroalkyl groups having from one to two carbon atoms, provided that not more than three of the R and R groups are perfluoroalkyl groups. R, and R are preferably fluorine. Preferred results are obtained when the total number of perfluorinated carbon atoms in each fluoroalkyl group is from five to 10 and the total number of fluoroalkyl groups is at least two. For convenience, the fluoroalkyl group is sometimes referred to hereinafter as R,.

The fluoroalkyl groups are pendent from an organic radical which makes the additive dispersible in the resin. Since the resin is normally basically a hydrocarbon containing functional groups, such as amide and ester linkages, dispersibility in the resin is achieved by having the organic radical portion of the additive molecule be of such structure as to effect chemical association, such as hydrogen bonding, between the resin and the organic radical portion. We have found that dispersibility can be achieved if the organic radical contains from 1 to 6 carbonyl groups (including the present in acyl groups), from 1 to 21 methylene groups, from 2 to 8 nitrogen atoms, and from O to 2 phenyl groups, provided the total number of carbon and nitrogen atoms is from to 35. In addition, the organic radi cal can contain other atoms, such as oxygen forming an ether linkage, which do not interfere with the dispersibility desired to be effected.

in addition to having the foregoing chemical structure, the additive must also possess certain physical properties. The additive must be substantially thermally stable at the temperature at which the filament is extruded. This temperature normally is within the range of 200 to 350 C. An additive is thermally stable if it survives the extrusion process without forming undesirable decomposition products and without decomposing to such an extent as to lose an appreciable amount of effectiveness in imparting soil and stain repellency to the filament. In addition to being thermally stable, the additive must also be nonfugitive, i.e., not

appreciably volatile, at the temperature of extrusion,

otherwise it would escape from the filament. A further requirement is that the additive must itself have a low surface energy in order to impart a low surface energy to the filament. To be suitable, the additive must have a surface energy of less than dynes/cm.

We have identified the following classes of compounds as being suitable additives in the practice of this invention:

A. Monoamides of the formula wherein R is an alkyl diradical of one to eight carbon atoms, an alkylene diradical of two to eight carbon atoms, or a phenyl diradical;

B. Diamides of the formula wherein R is an alkyl diradical of one to eight carbon atoms, an alkylene diradical of two to eight carbon atoms, a phenyl diradical, or a dicarboxy phenyl diradical having the formula C Hexahydrotriazines of the formula ll I ll RrCNHgNHCRr 20 wherein R is hydrogen, trichloromethyl, or a phenyl radical; E. lsocyanurate esters of the formula F. lsocyanurate esters of the formula N 0 ir 1 0 ll I (Riomoomcm NOHzCHZOoRi G. Substituted ureas of the formula H. Substituted ureas of the formula ll RiCNHCHzCHz (M) if CHzCHrNHCRr N-CNH-R-NHC-N RrCNHCHgCHz CHzcHzNHtlIllRr ll 0 O Mae ani;aaarmmiearar area; l3carb6n atoms, an alkylene diradical of two to 13 carbon atoms, or an aryl, aralkyl, or aralkylene diradical of six to 13 carbon atoms;

J. Substituted oxamides of the formula 0 0 II I moNHomom o o omcmmzrbm with a cyclic 'aaiayd'rraeaf'ihe farinma'" *w'h'ereinmame meaning previously givrifo r the ad- '7 ditives of Class A. The reaction is carried out in an inert solvent, such as acetone, at temperatures ranging from room temperature to the reflux temperature of the reaction mixture. The additives of Class A, as novel compositions of matter, are the subject of copending application Ser. No. 867,371, now U.S. Pat. No. 3,754,026, filed concurrently herewith, the pertinent subject matter of which is incorporated herein by reference.

The cyclic anhydride reactants are well known materials. The triaza reactants are readily prepared by reacting a lower alkyl ester of an acid having the formula R,COOH with an amine having the formula NH (Cl-l NH(CH Nl-l wherein R, has the meaning given for the compounds of this invention. Esters derived from acids having the formula R,COOl-l wherein the Y group of the R, component is F;,C are well Maximum use Surface temperenergy a e, dynes/ Class B; R 0. cm.

A C: 1 F2)a -(CH2)a- 225 13. 5 C3F1O (CFflr- (CH2)I 250 13. 5 CFs(CFz)n 2)a 200 15. 5

B C3F7O (CFg)3 250 14. 1

CFACFM- 300 12. 2 C3F7O (OFzh- 250 3 1 2)4 225 CF3(OF (monoester) 250 15. 5 CFa(CFn)o-(di65t8l) 260 12. 5 CF3(CF2)6(tYiBSt6l) 300 13. 0 O F O(CF )2(monoestei-) 250 16. 5 CaF1O(CF )@(d1estez-) 250 18-14 F CF (CFz)a(d16StBr) 260 14 G CF3(CF;)Q- 225 16 H F2)o- R1 is H, R: is gienyl 225 16. 5 a(CF2)e R1 and R are 225 16. 1

I CF3 CF 0- 260 15. 8

CF:(CF2)0- -(CH1)s 260 15 CF3(CF2)u 260 13 5 J CFa(CF)t- 300 15 1 Not tested.

PREPARATION OF ADDITIVES iiib'wh' materials and can be made from the acids, which are generally available commercially. Acids wherein Y has the formula can be prepared from a telomer halide having the formula wherein R and R have the afore-stated meanings, w and x are integers indicating the respective degrees of telomerization, and E is bromine or iodine. These telomer halides and their method of preparation are described in US. application Ser. No. 633,359 filed Apr. 25, 1967, now US. Pat. No. 3,514,487 the pertinent subject matter of which is incorporated herein by reference. The telomer halides are prepared by reacting telogens of the formula FOR-2 FCOCFzCFzE FRz wherein n is O can be prepared by reacting the corresponding telomer halide with ICN or (CN) at pressures above atmospheres and at temperatures above 300C. to form the nitrile, followed by hydrolysis of the nitrile in accordance with conventional methods to form the acid. Acids wherein n is greater than zero can be prepared by reacting the corresponding telomer halide with an alkali metal cyanide in the presence of dimethyl sulfoxide at temperatures between 60 and 100C. to form the nitrile, from which the acid can be prepared in accordance with conventional methods. The acid can also be prepared (regardless of whether n or O or greater) by reacting the telomer halide with sulfur trioxide, followed by hydrolysis of the reaction product to obtain the acid. By this method. the acid contains one less carbon atom than the telomer halide from which it was prepared. Also, the acid thus formed can be converted to the corresponding telomer iodide for further telomerization by reaction with alkali-free silver oxide to form the silver salt, followed by reaction of the silver salt with powdered iodine to form the telomer iodide. By this method, acids having either an odd or even number of hydrocarbyl or fluorocarbyl groups can be prepared.

The additives of Class B are prepared by reacting the triaza compound referred to above with a diacid chloride having the formula ClOCRCOCl, where R has the meaning previously given for the additives of Class B, with the exception that R is not a dicarboxy phenyl radical. In order to prepare the additive of Class B wherein R is a dicarboxy phenyl radical having the formula of a diacid chloride. The reaction is carried out in an inert solvent, such as acetone, at temperatures ranging from room temperature up to the reflux temperature of the reaction mixture. The additives of Class B, as novel compositions of matter, are the subject of copending application Ser. No. 867,373, now US. Pat. No. 3,697,562, filed concurrently herewith, the pertinent subject matter of which is incorporated herein by reference.

The additives of Class C are prepared by reacting a compound of the formula R,CN with trioxane in the presence of a catalytic amount, about 1 percent by weight, of a strong acid, such as H 50 The additives of Class C, as novel compositions of matter, and their method of preparation are the subject of copending application Ser. No. 867,370, now US. Pat. No. 3,657,235, filed concurrently herewith. Nitrile reactants having the formula CF,,(CF ),,,(CH ),,CN are known compounds and can be prepared from commercially available materials in accordance with known methods. Nitrile reactants having the formula can be prepared from telomer halides in accordance with the methods described in the penultimate paragraph above, which methods are described in greater detail in Canadian Patent Nos. 823,673 and 823,674, corresponding to U.S. Ser. Nos. 721,115 and 721,117 now US. Pat. Nos. 3,697,564'and 3,706,773, respectively, both US. applications having been filed on Apr. 12, 1968, the pertinent subject matter of which is incorporated herein by reference.

The additives of Class D are prepared by reacting a nitrile of the formula R,CN with an aldehyde of the formula RCHO, wherein R has the meaning previously given for the additives of Class D, in the presence of an acid catalyst. Additives having the I formula R,CONHCH NHCOR are obtained as by-products in the preparation of the additives of Class C. The additives of Class D, as novel compositions of matter, are the subject of copending application Ser. No. 867,372, now US. Pat. No. 3,786,093, filed, concurrently herewith, the pertinent subject matter of which is incorporated herein by reference.

The additives of Class E are prepared by reacting tris- (Z-carboxyethyl)isocyanurate with an alcohol of the formula R,OH under anhydrous conditions, using as a solvent a perfluorocarboxylic acid having up to eight carbon atoms. The reaction product contains a mixture of mono-, diand triesters. The additives of Class E, as novel compositions of matter, and their method of preparation are more particularly described in copending application Ser. No. 808,681, filed Mar. 19, 1969 now U.S. Pat. No. 3,629,255, the pertinent subject matter of which is incorporated herein by reference.

The additives of Class F are prepared by reacting tri(- 2-hydroxyethyl)isocyanurate with an acid having the formula R,COOH under anhydrous conditions using an inert solvent. The reaction product contains a mixture of mono-, diand triesters. The additives of Class F, as novel composition of matter, and their method of preparation are more particularly described in copending application Ser. No. 808,681, filed Mar. 19, 1969, the pertinent subject matter of which is incorporated herein by reference.

The substituted urea additives of Classes G, H, and I are readily prepared by refluxing the triaza compound previously referred to with the appropriate isocyanate or diisocyanate in a solvent such as acetone. The appropriate isocyanate or diisocyanate compounds are well known in the art. I

The additives of Class I are prepared in accordance with the method used to prepare the additives of Class B using oxalyl chloride as the diacid chloride reactant.

PREPARATION OF FIBERS The filaments of the invention are prepared by forming an intimate blend of the additive and the resin and then extruding the blend into filaments in accordance with methods known to the art. The method of forming the blend is not critical. The blend can be formed by treating the resin in powder form with a solution of the additive and then extruding and pelletizing the treated resin after it has been allowed to dry. Another method of forming the blend comprises dry blending the additive with the resin in powder form and then working the mixture on a rubber mill or similar device.

The incorporation of the additive into the resin does not interfere with the formation of the filament or fibers drawn therefrom. Although the fluoroalkyl groups of the additive tend to render the additive incompatible with the resin, the additive does not distrub the normal macroscopic homogeneity of the polymer phase. This is surprising in view of the cirtical rheological conditions involved in the extrusion of filaments and the drawing of fibers.

By examining the filaments of this invention with the aid of a photomicroscope, we have found that the additive can be present in the filament in any of the following ways: (a) as finely dispersed, randomly distributed particles in the resin matrix, (b) as finely dispersed particles concentrated at the fiber surface, as an invisible solution in the resin matrix. But regardless of how the additive is present, it effectively imparts antisoiling and antistaining properties to the filament.

In some instances, the surface energy of the filament can be lowered even further by annealing the filament after it has been extruded. Annealing increases the mobility of the additive and allows it to migrate to the surface of the filament. Annealing is preferably carried out at the highest practical temperature, which is normally just below the temperature at which degradation of the fiber occurs, and for an optimum period which can readily be determined for each particular fiber by simple experiment. For fibers prepared from nylon-6, the preferred period is two to four hours. Annealing is normally performed in an inert atmosphere, such as nitrogen, to prevent oxidative degradation of the fiber.

This invention is generally applicable to filaments prepared from any fiber-forming thermoplastic resin, such as polypropylene, polyamide, polyester, polyacrylonitrile and blends thereof. Particularly good results are obtained with polyamide and polyester resins (including blends" thereof), especially with polyamide resins.

When nylon-6or nylon-66 is the resin, especially preferred results are obtained using the additive l,7-bis(4- perfluoroisopropoxybutyryl l ,4,7-triazaheptane monoglutaramide.

The practice of this invention is illustrated by the following examples.

EXAMPLE 1 Preparation of Additive 60.4 grams of 1,7 bis(4-perfluoroisopropoxybutyryl)- l,4,7-triazaheptane were dissolved in 250 ml of acetone. To this solution was added a solution of 8.35 grams of glutaric anhydride in 100 ml of acetone. The reaction mixture was stirred at 50C for one hour, then cooled and diluted with water. The product layer was dissolved in ether, washed with water, treated with charcoal and finally dried over MgSO,. The product obtained after evaporation of the ether solution was 1,7 bis(4-perfiuoroisopropoxybutyryl)-l ,4,7-triazaheptane monoglutaramide, a waxy solid having a melting point of 80C, and was obtained at a yield of about 100 percent. Preparation of Fibers Commercially available pellets of nylon-6 were comminuted with Dry Ice. The additive was dissolved in acetone and applied to the comminuted nylon. The coated nylon was dried at C and 5 mm. Hg overnight, then extruded into monofilament and pelletized. The pellets were then extruded into fiber from a Reifenhauser extruder using a 7 hole, 20 mil die and a screen pack as filter. The resin was extruded at a temperature of about 260C and at an extrusion rate of 60 to feet/minute. The extrudate was quenched by an air stream at 16C. The denier was precontrolled by the rate of fiber take-up 'with subsequent variable melt draw. Filaments of 60 denier, l6 denier and 8 denier were prepared by this technique. The filaments were subsequently drawn at a ratio of 4:1. The filaments contained 1 percent by weight of the additive. Fiber Tests The surface energy of the filaments was measured and found to be as follows:

Undrawn Denier Surface Enerzv dvnes/cm.

Drawn 4:1 l822 4 27-32 2 35-40 In comparison, the surface energy of unmodified nylon- 6 fiber is about 46 dynes/cm. The surface energy of a fiber directly reflects its ability ot repel oil and water borne soil and stain.

The lower surface energy of the 60 denier fiber is presumably due to the more favorable surface to volume ratio of the fiber, which allows a greater concentration of the additive at the surface. However, we found that increasing the amount of additive to 1.5 percent effected no further decrease in the surface energy of the fibers, and that increasing the level to 2 percent tended to cause dripping in the spinning operation.

Photomicrographs of the fibers revealed no visible additive particles, indicating that the additive was either dissolved or very finely dispersed in the resin matrrx.

Annealing at 120150C for two to four hours in an inert atmosphere caused a lowering of the surface energy of the undrawn 16 and 8 denier fibers to 18-22 dynes/cm. and -27 dynes/cm. respectively. This indicates that the additive is capable of migrating through the resin matrix to the surface.

Neither scouring the fibers nor wiping them with CC], produced any change in the surface energy.

The fibers were dyed according to standard procedures using various commercially available dyes, such as Necelan Blue FFRD, C.l. Disperse Blue 3 and Kiton Fast Blue CB. It was found that the fibers containing the additive were as receptive to the dye as unmodified fibers and that the dye was just as 'colorfast when the fibers were subjected to laundering and drycleaning. Furthermore, dyeing had no adverse effect on the surface energy on the fibers containing the additive.

A test cloth was prepared using the 15 denier fiber and the ability of the cloth to resist common household stains, including catsup, French dressing, spinach, chocolate and hot coffee, was compared with that of a control cloth prepared from unmodified nylon-6 fiber. The cloth prepared from the modified fiber had better stain resistance and also exhibited better stain release during subsequent laundering.

EXAMPLE 2 Preparation of Additive To 202 grams perfluorooctanoyl chloride were added 45 ml anhydrous methanol. The temperature rose to about 65C. as HCl was evolved. An additional liter of methanol was added over a period of about one hour. The mixture was then heated at about 65C. for about 90 minutes. The reaction product was separated from the layer of unreacted methanol, washed with water, dried overnight over Na SO crystals, filtered and distilled. 164 grams of methyl perfluorooctanoate were recovered.

To the methyl ester prepared above were added 20.6 grams diethylene-triamine dropwise, with the temperature rising to about C. The mixture was maintained at that temperature for one hour with stirring. The reaction product solidified as the mixture cooled to room temperature. The product was recrystallized from acetonitrile and dried overnight at 60C. and 1 mm Hg. 135 grams of 1,7 bis(perfluorooctanoyl)-1,4,7- triazaheptane were recovered. v

To a solution of 8.9 grams of the triaza compound prepared above in 40 ml of acetone were added a solution of 1.5 grams glutaric anhydride in 10 ml of acetone. The mixture was stirred at room temperature for about 20 minutes, at which time a haze, indicating a precipitate, developed. The mixture was stirred for another four hours and then allowed to stand overnight. The product was recovered by filtration, washed with water, and vacuum dried. 9.7 grams of 1,7 bis(perfluorooctanoyl)-l ,4,7-triazaheptane monoglutaramide were recovered.

Preparation of Fibers Fibers were prepared using 1.0 percent of the additive prepared above. An undrawn filament having a diameter of 16 mils (about 1300 denier) had a surface energy of less than 18 dynes/cm. When the filament was drawn 4:1, the resulting fiber had a surface energy of 22 dynes/cm.

Photomicrographs of the fibers revealed that the additive is present as a distinct band under the skin of the fiber. This is in contrast to Example 1, where the additive was not visible at all.

EXAMPLE 3 Preparation of Additive 985 grams of 1,7 bis(perfluorooctanoyl)-l ,4,7- triazaheptane and 143 grams of triethyl amine were dissolved in 5 liters of acetone. To this solution was added dropwise a solution of 1 12 grams of isophthalylchloride in one liter of acetone. The reaction mixture was stirred at 50C for 4 hours, then cooled to room temperature. The resulting precipitate was recovered, washed with acetone and was recrystallized from hot ethanol. The product was 1,7 bis(perfluorooctanoyl-l ,4,7- triazaheptane isophthalamide, a white solid having a melting point of 178C, and was obtained at a yield of percent. Preparation of Fibers Fibers were prepared using 0.1, 0.25, 0.50, and 1.0 percent of the additive prepared above. The surface energy of the fibers is tabulated below:

Surface Energy, dynes[cm.

Concentration of Additive, Undrawn( 16 mils) Drawn(4 mils) ergy.

EXAMPLE 4 Preparation of Additive l,7-Bis(perfluorooctanoyl)-l ,4,7-triazaheptane adipamide was prepared following the general method of Example 3, except adipyl chloride was substituted for isophthalylchloride. The product was a white solid having a melting point of 190195C. Preparation of Fibers Fibers were prepared using 1 percent of the additive prepared above. An undrawn filament of 60 denier had a surface energy of less than 18 dynes/cm. When the filament was drawn 4:1, the resulting fiber had a surface energy of 25 dynes/cm.

Photomicrographs of the fibers revealed that the additive was present as a random distribution of particles throughout the resin matrix.

EXAMPLE 5 Preparation of Additive A mixture of 258 grams of 12,12,13,l3,14,14,l5,15- octafiuoro-l 5-heptafluoroisopropoxypentadecanoic acid and 410 grams of thionyl chloride was heated to reflux over a period of 40 minutes and then maintained at reflux for 3 hours. The reaction mixture was cooled to room temperature and excess thionyl chloride was evaporated off under vacuum to give 267 grams of crude acid chloride.

To a stirred solution of the crude acid chloride in 750 ml of benzene at C was added 24.2 grams of N,N- dimethylaniline over a period of minutes. A solution of 32.5 grams of activated sodium azide in 100 ml of water was then added dropwise over a period of minutes as the temperature was maintained at less than 10C. The reaction mixture was stirred for 30 minutes at 5-10C, and then at room temperature for 90 minutes. The benzene layer was separated, extracted with cold 10 percent hydrochloric acid, dried over sodium sulfate, heated to reflux and maintained at reflux for two hours. The product was (CF;,) CFO(CF (CH NCO, a colorless oil having a boiling point of 1 19C at 0.5 mm Hg. This compound and its method of preparation are the invention of our colleague .1. Murray and are the subject of US. Pat. No. 3,657,306.

The compound 12,12,13,13,14,14,15,15-octaflu0ro- 15-heptafluoroisopropoxypentadecanoic acid is a known compound, being described in Canadian Patent Nos. 823,673 and 823,674, corresponding to US. Ser. Nos. 721,115 and 721,117 now US. Pat. Nos. 3,697,564 and 3,706,773, respectively, both US. applications having been filed on Apr. 12, 1968. Preparation of Fibers Fibers were prepared using 1 percent of the additive prepared above. An undrawn filament of 60 denier had a surface energy of 27 dynes/cm. When the filament was drawn 4:1 the resulting fiber had a surface energy of 32-35 dynes/cm. However, when the fiber was annealed at 130-140C for two hours, the surface energy was reduced to 27 dynes/cm. We theorize that during the drawing operation the additive is not sufficiently mobile to keep replenishing the newly generated surfaces, but that during the annealing step the additive migrates to the surface to render it equivalent to the surface of the undrawn fiber.

EXAMPLE 6 Preparation of Additive 65 grams of C;,F O(CF CH CH CN and 0.7 grams concentrated sulfuric acid in 100 m1 of carbon tetrachloride were warmed to reflux. A solution of 4.6

grams of trioxane in ml of carbon tetrachloride was added dropwise over a period of two hours. The reaction was continued at reflux for an additional two hours. The product precipitated upon cooling, was washed with water, dried, recrystallized from carbon tetrachloride and identified as 61.0 grams of white product, melting point 8183C, were obtained at a yield of 89 percent. From the mother liquor were recovered 7.0 grams of the bisamide Preparation of Fibers The two compounds prepared above are used in accordance with this invention to prepare fibers having improved soil and stain repellency.

EXAMPLE 7 Preparation of Fibers The additive prepared above is used in accordance with this invention to produce fibers having improved soil and stain repellency.

EXAMPLE 8 Preparation of Additive 89 grams (0.01 mol) of 1,7-bis(perfluorooctanoyl)- l,4,7-triazaheptane and 1.20 grams (0.01 mol) of phenylisocyanate were reacted in 50 ml of acetone for 5 minutes at reflux temperature. The reaction mixture was left standing at room temperature overnight. The mixture was diluted with an excess of water, which caused the product to separate as an oily layer which l l6 gradually solidified. The product was filtered off, air wiikifiki afiai'ky'r'dir'ma'6? one to eight carbon dried, and recrystallized from ethanol-water. The prodatoms, an alkylene diradical of two to eight carbon uct, a white solid having a melting point of l 15l 18C, atoms, or a phenyl diradical; was obtained at a 95 percent yield and was identified b. diamides of the formula as N,N-bis(perfluorooctanamido ethyl)-N-phenyl 5 urea. W W H Mm W W M Preparation of Fibers The additive prepared above is used in accordance L with this invention to produce fibers having'improved soil and stain repellency.

v R('C-NHGHZCHZ CHzCH1NHC-Rl EXAMPLE 9 1 ll (i The additive having the formula pared in 98 percent yi ld by r ti wherein R is an alkyl diradical of one to eight carbon C F O(CF C1-l N1-l with atoms, an alkylene diradical of two to eight carbon atoms, a phenyl diradical, or a dicarboxy phenyl diradi- CHNCHOHhEfl) cal having the formula The additive is suitable for use in this I f 20 EXAMPLE 10 The additive a-(perfluorooctanoamido)caprolactam, melting point 159C, was prepared in 64 percent yield by reacting methyl perfluorooctanoate with a-amino caprolactam. The additive is suitable for use in this invention to impart soil and stain repellency to extruded h h d n-i i f th f l synthetic fibers.

EXAMPLE 11 3 Fibers were prepared from a blend of percent (i=0 polyethylene terephthalate and 70 percent nylon-6 1; containing 0.5 percent of the additive of Example 3. An 0 I 0 undrawn filament having a diameter of 16 mils had a g E surface energy of less than 18 dynes/cm. When the fiber was drawn 4:], the resulting fiber had a surface energy of 22 dynes/cm.

EXAMPLE l2 drbisamides ofthe formula Fibers were prepared from polypropylene containing 1 percent by weight of 1,7 bis(perfluorooctanoyl)-4- R stearoyl-l,4,7-triazaheptane. An undrawn filament of moNHoNHcRi 60 denier had a surface energy of less than 18 dynes/cm. A control fiber containin no additive had a Surface energy of 22 dyneS/Cm g R 15 hydrogen, trichloromethyl or a phenyl EXAMPLE 13 e. isocyanurate esters of the formula Fibers were prepared from polyethylene terephthalate containing 1 percent of the additive of Example 3. An undrawn filament of 60 denier had a surface energy CIFHZCECOOHPRO of 27 dynes/cm. When the filament was drawn 4:1, the N\ resulting fiber had the same surface energy, 27 dy- O =0 nes/cm. A control fiber of polyethylene terephthalate (RQHOOCCHzCHg-N NCH,CH,COOR| containing no additive had a surface energy of 42 dynes/cm. 0

We claim:

1. An extruded filament of a fiber-forming polypropyl ene having dispersed therein from about 0.1 to 1 about 2 percent based on the weight of the polypropylene of an additive which improves the soil and stain repellency of the filament, said additive being selected from the group consisting of mfrisocyanurate esters of the formula g. substituted ureas of the formula h. substituted ureas of the formula RicNHcmoHz i. substituted ureas of the formula wherein R is an alkyl diradical of one to 13 carbon atoms, an alkylene diradical oftwo to 13 carbon atoms, or an aryl, aralkyl or aralkylene diradical of six to 13 carbon atoms;

j. substituted oxamides of the formula (1 itiiimiou'zonz cmonmm i-m NCCN RrCNIICHzCI h anatomic-'12,

R, being, in each of the above formulas, the fluoroalkyl group having the formula wherein m is an integer from 1 to 16, n is an integer not greater than m from O to 8, with the sum of m plus n being from 1 to 20, and Y is selected from the group consisting of F C- and radicals having the formula wherein R and R are fluorine or perfluoroalkyl groups having from one to two carbon atoms, provided that no more than three of the R and R groups are perfluoroalkyl groups, said additive further having a surface energy of less than 20 dynes/cm. and being thermally stable and nonfugitive at the temperature at which the filament is extruded.

2. The filament of claim 1 wherein the R, group has from 5 to 10 perfluorinated carbon atoms.

3. The filament of claim 2 wherein the additive is present in an amount of from 0.5 to 1.5 percent by weight based on the weight of the polypropylene.

mg C UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,839,312 Dated October l, 1974 Inventor(s) Bryce C. Oxenrider and Cyril Woolf It is certified that after appears in the shove-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 5, line 42, "C3H7O..-." should be C F7O...

Column 7, line 38, "OsF" should be CsF i li 67, "01"" first occurrence should be 1s A Co'lumnlZ, .line 41, ."bis(perfluorooctanoyl-l,4,,7"'a

should be bis(perfluorooctanoyl)-l,4', 7

Claim 1, column l6 j line 66, N. should be l a 1 v Claim 1, column l7',". line ll, should be 0 I N-C-N u N-C-N Signed and sealed this 11th day of February l 975.

(SEAL) v Attest:

C. MARSHA-LL DANN RUTH C. MASON I e Commissioner of Patents Attesting Officer I and Trademarks

Claims (3)

1. AN EXTRUDED FILAMENT OF A FIBER-FORMING POLYPROPYLENE HAVING DISPERSED THEREIN FROM ABOUT 0.1 TO ABOUT 2 PERCENT BASED ON THE WEIGHT OF THE POLYPROPYLENE OF AN ADDITIVE WHICH IMPROVES THE SOIL AND STAIN REPELLENCY OF THE FILAMENT; SAID ADDITIVE BEING SELECTED FROM THE GROUP CONSISTING OF

2. The filament of claim 1 wherein the Rf group has from 5 to 10 perfluorinated carbon atoms.

3. The filament of claim 2 wherein the additive is present in an amount of from 0.5 to 1.5 percent by weight based on the weight of the polypropylene.