United States Patent Gfifice 3,039,895 Patented June 19, 1962 3,039,895 TEXTILE James P. Yuk, Waynesboro, Va., assignor to E. I. du Pont de Nemours and Company, Wilmington, Del., a corporation of Delaware No Drawing. Filed Mar. 29, 1960, Ser. No. 18,264 16 Claims. (Cl. 117138.8)
This invention relates to oiled elastic structures and in particular to elastic filaments of synthetic segmented elastomeric copolymers having an oil-based lubricant thereon.
It is well known that an elastic filament made of rubber of of a segmented copolymer, e.g., of the spandex type, cannot be processed if free of a lubricating finish. Such elastic fibers have a greater tendency than do hard fibers for cohesion of adjacent filaments of the yarn to one another and for sticking of the yarn to other surfaces, which causes erratic running tensions. Furthermore, it has been generally accepted that oils cannot be used to lubricate rubber filaments because of the harmful effect of such oils on physical properties. Accordingly, a material such as talc is usually used for lubricating filaments made of rubber, and talc may be used to lubricate spandex filaments. For this application tale is usually applied to the filaments from a slurry in water or in some organic liquid, e.g., alcohol or acetone, which is not an oil.
The use of talc as a finishing agent for elastic filaments is attendant with many disadvantages. Both in manufacturing and in processing a talc-coated filament, talc is spattered around the area in which the yarn is being processed and creates a housekeeping nuisance as well as a dust hazard. Use of talc produces a package with very poor over-end take-off properties. These are attributed to the cohesion of the filaments within the package. The package must accordingly be rewound or a rolling takeofi must be used. Talc presents serious abrasion problems, both on spinning machines and on processing equipment. In knitting, latch needles and cylinder head dials are worn out quickly by the abrasive action of the talc, and the star-wheels of yarn-covering machines are similarly affected. Poor stability of the talc slurry prevents the uniform application of the finish, and the talc content of elastic filaments may be subject to wide variation. Since the talc slurry usually contains a certain amount of water, a drying step is required, and the yarn must be wound on relatively expensive plastic cores.
In addition to talc, a great number of other lubricating materials commonly used in textile processing have been tried; however, none have proved to be fully satisfactory. Some are readily absorbed by the elastic filament and when applied in a suificient quantity to provide lubricating properties exude excessively when the filament is elongated under tension. Others form films that provide satisfactory lubrication when only slight tensions are encountered but break down when the filaments are elongated under higher tensions. Still others do not provide emulsions, solutions, and dispersions which are stable.
It is, therefore, an object of this invention to provide an elastic filament with a lubricating finish which may be processed without difficulty. A more particular object of this invention is to provide an elastic filament with an oil finish which has good stability, does not discolor, prevents cohesion of filaments on a wound package, and provides adequate frictional properties on the fiber when in a stretched condition. Another object is to provide an elastic filament with a lubricating finish that afiords antistatic protection of the filament. Still another object is to provide a lubricated elastic filament which is non-abrasive and non-irritating to the skin. A further object is to provide elastic filaments with an oil finish that, for certain end uses, do not need to be scoured. Other objects will be apparent from the following detailed description.
The objects of this invention are accomplished by providing an oiled elastic structure comprising a filament of a synthetic segmented elastomeric copolymer having a substantially anhydrous lubricating finish comprising a textile oil having dispersed therein finely divided particles of a Group I, II or III metal salt of a higher fatty acid.
The segmented copolymer which makes up the elastic filament of this invention consists of segments of a highmelting, crystalline polymer alternating with segments of a low-melting, amorphous polymer. The crystalline highmelting segment may be derived from, for example, a polyurea, polyurethane, polyamide, bis-ureylene polymer, or polyester. The low-melting amorphous segment may be derived from, for example, a polyester, a polyether, or a hydrocarbon polymer. Polymers of the spandex type are illustrative of such a segmented copolymer.
The segmented copolymers described in several patents are useful in the practice of this invention. Among these are U.S. Reissue Patents 24,689 and 24,691, British Patent 779,054, French Patent 1,172,566, and U.S. Patents 2,929,801, 2,929,802, 2,929,803 and 2,929,804. As disclosed in these references, such segmented copolymers when in filament form display elongations at the break in excess of 200%, elastic recovery (or tensile recovery) above about and stress decays below about 20%. The terms elastic recovery and stress decay are defined in U.S. Reissue 24,689, now abandoned.
By the term textile oil is meant the organic liquids with which textile fibers are normally treated during processing, such liquids being in general oils of low volatility that serve to lubricate the fibers, for instance, tallows, naphthenic oil, sulfated or sulfonated oils, aromatic oils, paraifinic oils, and synthetic oils such as the silicones.
l fixtures of oils may be used if desired. For example, it has been found that the addition of a boundary lubricant to a mineral oil base reduces the tendency for cohesion of the filaments on a wound package in the practice of this invention. Suitable boundary lubricants include bodied peanut oil, alkanolamine fatty acid condensates, and the polyoxyalkylenes such as copolymers of ethylene oxide and propylene oxide. When a boundary lubricant is employed in addition to the base oil, it is preferred to employ in addition thereto a supplementary fluid lubricant which acts as a blending agent and a dispersing aid. Examples of such supplementary fluid lubricant are acetylated castor oil and the long-chain esters of sorbitan. Acetylated castor oil is a preferred supplementary fluid lubricant.
I have discovered that textile oils make a satisfactory finish for elastic filaments from segmented copolymers only when there is dispersed in such oils essentially colorless, finely-divided soaps of certain metals of Groups I, II, and III of the periodic table. Metals of Group Ia of the well-known Mendelyeevs Periodic Table are useful and include those having atomic weights between about 7 and 133, i.e., lithium, sodium, potassium, rubidium, and cesium. Metals of Group H include those having atomic weights between about 24 and 137, i.e., magnesium, calcium, strontium, barium, zinc, and cadmium. From Group III, aluminum which has an atomic weight of about 27 may be used.
The higher fatty acids are the C to C saturated and unsaturated fatty acids. The soap, which is the salt of these fatty acids, may be prepared, of course, from substituted acids such as ketoand hydroxy acids, for example, 4-keto-stearic acid or lZ-hydroxy stearic acid, instead of fatty acids, or in admixture therewith, if desired. In all cases, a fatty acid-metal combination is suitable if the resulting soap is essentially colorless and may be obtained in a finely divided state. Thus, with the metals indicated, any of the acids described above may be used, since these soaps are obtainable as finely divided particles which, as will appear more fully hereinafter, is critical to the practice of this invention.
Representative examples of suitable soaps include sodium capra-te, sodium laura-te, sodium behenate, potassium oleate, potassium myristate, lithium stearate, lithium pal-mitate, zinc stearate, calcium oleate, magnesium lau rate, aluminum trioctoate, and aluminum distearate. The preferred soaps are those of the Group II metals, especially those of zinc, calcium and magnesium. Magnesium stearate is particularly preferred.
In the practice of this invention it is important that the particle size of the dispersed soaps be in a critical range. In particular, the average radius of the dispersed particle as determined by standard light scattering methods should fall in the range 0.05 to microns. Preferably, the dispersed particles fall within the range 0.2 to 1.5 microns.
Since the particle size and amount of dispersed soap in the oil finish affects the viscosity thereof, the upper limit of the soap content in the finish is governed by the limit of a-practical working viscosity. In order to avoid possible gelling and viscosity differences, the dispersions should be prepared at room temperature and used at room temperature. Although viscosities as high as several poises may be employed, a :low viscosity finish, i.e., less than about 70 centipoises, is generally preferred to be used with the elastic filaments from segmented copolymers. A minimum amount of dispersed soap is necessary to achieve the benefits of the present invention. This minimum quantity is about 2% by weight of the finish. Accordingly, the oil finish of this invention contains approximately 2% to 20% by weight of dispersed solids. The preferred compositions contain about 5% to 13% of dispersed solids.
The finishes of this invention may be applied to elastic fibers in any convenient manner. In general, the finish may be applied by any of the standard procedures such as by dipping, padding, or spraying. Running yarns may be treated, for example, by spraying, or by passing them through baths or over wicks or other similar devices from which they pick up the finish. Passing the filaments over a roller which dips into a trough containing the finish is a convenient method of application. When the finish is continuously applied to elastic fibers as they are being spun, the trough-roller apparatus is preferably located at a point on the threadline just beyond the first driven feed roll which the elastic filaments contact after leaving the spinneret.
Ordinarily, an oiled elastic filament treated accor ing to the present invention will contain less than about by weight of the finish. It has been found that the minimum amount of finish required to afford sufiicient protection to the yarn is about 3.5% by weight. The preferred minimum amount of finish is about 5% by weight, and the preferred amount of finish on an oiled elastic filament of this invention is in the range of 5% to 8%.
This invention will be further illustrated, but is not intended to be limited by, the following examples in which parts and percentages are by weight unless otherwise specified.
Example I Ninety-two (92) parts of polytetramethylene ether glycol (0.092 mol) of approximately 1000 molecular weight is reacted with 8 parts of 2,4-tolylene diisocyanate (0.046 mol) under an atmosphere of nitrogen for three hours at 80 C. The product of this reaction (40 parts), having terminal hydroxyl groups, is reacted with 10 parts of p,p'-methy1ene diphenyl diisocyanate for one hour at 80 C. The product of this reaction, having terminal isocyanate groups, is diluted with 25 parts of N,N'-dimethylformamide. Fifteen parts of this solution is chain extended by addition to 0.165 part of hydrazine hydrate in 30 parts of dimethylforniamide. The resulting solution of elastomeric polymer contains aproximately 20% solids, and has -a viscosity of 400 to 500 poises at 30 C. To this solution are added a slurry of titanium dioxide in dimethylforma-mide and a solution of poly(N,N-diethyl-'beta-aminoethyl methacrylate) in dimethyl-formamide such that the final mixture contains 5% of each additive based on the elastomeric solids.
The foregoing mixture is heated to a temperature of 50 C. to 70 C. and spun as a l5-filament yarn into a dry spinning column heated with nitrogen at 250 C. At the bottom of the column, the filaments are allowed to come into contact and coalesce to give a monofilament of about 300 denier. Upon emergence from the column, the monofilament is treated with a finish having the following composition:
Percent Mineral oil (No. 50) 75 Blown peanut oil (viscosity 250 centistokes) 5 Acetylated castor oil (Flexricin P8 10 Zinc stearate l0 Trademark of Baker Castor Oil Company. When unwound from a bobbin, the oiled elastic filament shows substantially no tendency to stick to adjacent filamerits.
' Example 11 A finish having the following composition is applied to the as-spun untreated monofilaments of Example I:
Percent Mineral oil (No. 50)) 72 Acetylated castor oil (Flexricin P-8 10 Blown peanut oil (viscosity 250 centistokes) 5 Magnesium stearate 13 The monofilaments of the elastic yarn of Example I, upon emergence from the spinning column, are treated with an oil finish having the following composition:
Percent Mineral oil (No. 50) 62 Acetylated, partially alcoholized castor oil (Flexricin 62* 15 Blown neats-foot oil (viscosity 300 centistokes) 5 Copolymer of ethylene oxide and propylene oxide (Ucon LB358 Sorbitan ethylene oxide distearate (G-1052 5 Zinc laurate 8 1 Trademark of Baker Castor Oil Company. Trademark of Carbide 8:: Carbon Chemical Company. 8 Sold by Atlas Powder Company.
Results with the oiled elastic filament similar to those of Examples I and II are obtained.
Example IV A finish having the following composition is applied to the as-spun untreated monofilaments of Example I:
Percent Mineral oil (No. 50) 75 Blown peanut oil (viscosity 250 centistokes) 5 Acetylated castor oil (Flexricin P8 10 Sodium stearate l0 'l'radeniark of Baker Castor Oil Company.
Results with the finished yarn are similar to those from Example I.
Example V A finish having the following composition is applied to the as-spun untreated monofilaments of Example I:
Percent Mineral oil (No. 50) 75 Blown peanut oil (viscosity 250 centistokes) 5 Acetylated castor oil (Flexricin P-8 Aluminum distearate (Witco aluminum stearate 1 Trademark of Baker Castor Oil Company.
1! Sold by the Witco Chemical Co.
Results with the finished yarn are similar to those from Example I.
In all of the above examples, the metal salts are dispersed in the other components of the finish, and the dispersed particles have an average radius in the range 0.05 to 5 microns. The physical properties of the elastic yarn of the above examples are not adversely affected by the presence of the oil finish. Tenacity, elongation, modulus, stress decay, and elastic or tensile recovery are measured and found to be essentially equal to the same properties of the identical elastic filament having a talc finish. Substantially similar results are obtained when a polyester or N-alkylated polyurethane is substituted for the polyether in the pandex yarn of the examples. Substantially similar results are also obtained when a urea segment, urethane segment, or amide segment is substituted for the bisureylene segment of the spandex yarn of the examples.
The oiled elastic yarns of this invention may be used in both the covered and uncovered states. Covered yarns of improved appearance can be made with fewer breaks on the covering machine than with spandex yarns having a talc finish. Because of the more uniform finish content,
better lubrication and tension control in the yarns of this I invention, knitting can be done directly from the packages of the as-spun yarn, instead of rewinding, as is commonly done with yarns having a talc finish. The yarns of this invention may be used to produce novel end products, for example, in the field of Raschel knitting, where the use of rubber filaments or spandex filaments having a talc finish is impractical.
As pointed out hereinbefore, the use of a substantially anhydrous finish composition affords many advantages over finishes containing water. Thus, drying of spin packages is eliminated, paper cores may be used instead of the more expensive plastic cores, maintenance due to rusting is lessened, and housekeeping is simplified.
The oil-based finish of this invention has the added advantage that the dispersed soaps afford antistatic protection to the elastic filaments. In this respect, magnesium stearate is outstanding. Consequently, the use of special antistatic agents in the practice of this invention is not required. Moreover, the oiled elastic filaments are free of objectionable color. This freedom from undesirable color is important in many of the applications for which the filaments of this invention are suited.
In the above examples a monofilament yarn of large denier is formed by coalescence of many smaller filaments before applying the oil-based finish to form the filaments of this invention. Alternatively, individual fine-denier filaments (for example, 6 denier or less) may be first treated with the oil-based finish, then collected into a continuous filament tow which may be cut into staple. The elastic filaments of staple length are useful in the formation of elastic yarn.
The oiled elastic filaments of this invention are useful in a Wide variety of products in both the covered and uncovered state. The filaments of this invention find particular utility in foundation garments, girdles, corsets, surgical hosiery, woven or knitted swim Wear, socks and sock tops. The filaments are also useful in brassiers, suspenders, garters, slip tops, lingerie straps for slips and brassieres, form fitting hosiery afterwelts, support hosiery, surgical bandages and tapes, medical supports, panties,
waistbands, leg bands, wristlets and jacket trim, dresswear, rainwear, skirts, sweaters, belts, suits, coats, hats, slacks, pajamas, skin diving suits, leotards, athletic uniforms, polo shirts, ski clothing, golf jackets, golf balls, golf club mittens, gloves, sling shots, watch straps, narrow tapes and webbings, braids, sewing thread, hairnets, chin straps, shoe gores, shoe fabrics, carpets and rugs, furniture upholstery, slip covers, automobile upholstery, mattress covers, fitted sheets and bedding, ticking and quilting fabric, laundry bags, card table covers, shock cord core, industrial belting, wire and cable jackets, antigravity suits, crash barriers, wall covering, tou-pee bases, face masks, woven and nonwoven fabrics, felts, papers, book covers and jackets, coatings, protective coverings,
' swimming pool covers, flannels, and protective clothing.
The filaments of this invention may be blended with relatively nonelastic filaments, e.g., nylon and/or nonelastic filaments in the stretchy form for making a wide variety of elastic or stretchy products including woven, knitted and nonwoven fabrics for use in universal fitting apparel, e.g., socks, stockings, elastic cuffs, action sportswear, and others as listed hereinbefore; household products, e.g., form-fitting upholstery; industrial products, e.g., woven and nonwoven felts, synthetic leather, filter fabrics, stuffing material, boat covers, balloon fabrics, sleeping bags, hammocks, automobile tops, and tarpaulins; and medical products, e.g., surgical stockings and splint tapes. The filaments of this invention can be employed in the aforementioned applications in the form of either continuous filaments or as a blend of staple fibers, as appropriate.
This application is a continuation-in-part of copending US. application Serial Number 852,194, filed November 12, 1959, now abandoned.
As many widely different embodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that this invention is not to be limited to the specific embodiments thereof except as defined in the appended claims.
I claim:
1. An oiled elastic structure comprising a filament of a synthetic segmented elastomeric copolymer having thereon at least about 3.5% by weight of a substantially anhydrous lubricant, said lubricant comprising a textile oil and from about 2% to about 20% by weight of finely divided particles of a metal salt of a fatty acid containing from about 8 to about 22 carbon atoms, said metal being selected from the class consisting of Group Ia metals having an atomic weight between about 7 and 133, Group II metals having an atomic weight between about 24 and 137, and a Group III metal having an atomic weight of about 27, said particles having an average radius in the range between 0.05 and 5 microns.
2. The product of claim 1 wherein said lubricant contains from about 5% to about 13% by weight of said particles.
3. The product of claim 1 wherein said lubricant is present in an amount from about 5% to about 8% by weight of said filaments.
4. The product of claim 1 wherein said particles have an average radius in the range from 0.2 to 1.5 microns.
5. The product of claim 1 wherein said salt is magnesium stearate.
6. The product of claim 1 wherein said filament is 9. spandex filament.
7. A filament of a synthetic segmented elastomeric copolyrner having a lubricating finish thereon comprising from about 5% to about 13% of its weight, said finish containing about 72% of a mineral oil, about 10% acetylated castor oil, about 5% bodied peanut oil, and about 13% magnesium stearate, said magnesium stearate being dispersed in said lubricating finish in the form of finely divided particles having an average radius in the range between 0.05 and 5 microns.
8. The product of claim 7 wherein said filament is a spandex filament.
9. The product of claim 7 wherein said segmented elas tomeric copolymer is a segmented polyurethane having intralinear nitrogen-to-nitrogen bonds.
10. An oiled elastic structure comprising a filament of a synthetic segmented elastomeric copolymer having thereon at least about 3.5% by weight of a substantially anhydrous lubricant, said lubricant comprising a textile oil and from about 2% to about 20% by weight of finely divided particles of a colorless metal salt of a fatty acid containing from about 8 to about 22 carbon atoms, said metal having a valence not greater than 3 and an atomic weight between about 7 and about 137, said particles having an average radius in the range between 0.05 and 5 microns.
11. The product of claim 10 wherein said metal is sodium.
8 12. The product claim magnesium.
13. The product zinc. 14. The product calcium.
15. The product barium.
16. The product aluminum.
claim claim claim 1. 10 cam wherein said said
said
said
said
metal metal metal metal metal References Cited in the file of this patent UNITED STATES PATENTS Sherman July 9, 1940 Licita et a1 Nov. 26, 1940