US2369395A - Yarnlike structure - Google Patents

Description

Feb. 13, 1945 K. HEYMANN YARN-LIKE STRUCTURE Filed Jan; 21, 1942 INVENTOR. AA/PA H5 YMA N/\/ 5 k 4 ATTOR Patented Feb. 13, 1945 YARNLIKE STRUCTURE Karl Heymann, Meadville, Pal, assignor to American Viscose Corpnration, Wilmington, DeL, acorporation of Delaware Application January 21, 1942, Serial No. 427,563

7 Claims. (01. 28-81) This invention relates to yarn-like structures of artificial filaments exhibiting a wooly, fluffy character and to processes of making them.

The natural woolsare composed of short fibers, which are formed into fabrics by felting, spinning, weaving, and fulling processes. Such fabric materials, being composed of fibrous masses having numerous ends, cause a scratching or an itching sensation when they come into contact with the skin of the wearer. The woolen fabrics, such as flannels, blankets, and certain suitings whether they'are manufactured by the evaporative or the coagulative spinning processes, are

' subjected, in the form of a bundle or group, to a which have been fulled commonly have this effect, and the free fiber ends in combination with the high resiliency and elasticity of the crimped fibers are largely accountable for this sensation which is at times extremely annoying to the wearer. It has heretofore been proposed to make artificial wool-like masses by imparting a crimp or curl to fibers of certain synthetic materials having staple lengths and spinning the crimped fibers to form a yarn. Such known yarns as have yielded somewhat improved skin sensations have done so, with but few exceptions,

' only with the sacrifice of resiliency and elasticity of the fibers making up the substitutes. Such a sacrifice is inconsistent with the obtention of the most desirable wool-like properties, such as the retention through long periods of hard wear and usage of a loose, fluffy fibrous mass which is necessary to impart the desired heat insulation capacity.

Figure l is a somewhat enlarged view of a fluffy yarn-like structure made in accordance with the invention, showing its general external appearance, and

Figure 2 is a greatly enlarged view showing the disposition of the filaments in a given plane within a yarn having substantially no twist, illustrating one embodiment of the invention.

In accordance with this invention, it has been found that a textile material in yarn-like form and having extremely wool-like properties may readily be obtained from continuous filaments of polyvinyl resins, such as polyvinyl chloride and more particularly the co-polymers of vinyl chloride and vinyl acetate described in the Rugeley Patent 2,161,766, halogenated polyvinyl resins, such as chlorinated polyvinyl chloride and the chlorinated co-polymers of vinyl chloride and vinyl acetate described in the Lytton and Taylor application Serial No. 403,530 filed July 22, 1941 patented October 26, 1943, No. 2,332,974. It has been found that when continuous filaments of these resins which have been stretched, either during their spinning or after their coagulation certain degree of heat, preferably in an indifferent medium, while limplysuspended, a shrinkage occurs and that this shrinkage is accompanied by the production of a crimpyness or curlyness in the filaments which is highly irregular and of such a fine degree that it imparts to the filaments anappearance and fluifiness similar to that of natural wool without the fuzziness thereof associated with fiber ends. The fine and delicate yet permanent crimp obtainable by the process of the invention should not be confused with the comparatively coarse crimp heretofore imparted to other filamentary materials by such unrelated means as mechanical working which has the serious disadvantage of reducing the elasticity of the filaments, particularly at the places of bending. It has been found that such shrinkage and crimping as is produced in accordance with the invention is accompanied by substantially no loss of elasticity so that fabricated materials made from such filaments are found to exhibit and maintain through hard usage a loose, fluffy character and heat insulating qualities of the same order as those exhibited by woolen fabrics.

Resin filaments having any amount of stretch may be employed. For example, filaments which have been stretched to several hundred per cent of their original length as well as those which have been stretched to less than one hundred per cent of their original length may be heated to impart a partial ora complete shrinkage thereof. When highly stretched filaments are employed, however, it may be desirable not to effect complete shrinkage because of the concomitant excessive decrease in length which, be-

ing accentuated by virtue of the crimping, may

make the'material too expensive from a commercial standpoint to be practical for certain purposes. Inasmuch as the degree of shrinkage of any of the resins may be controlled merely by controlling the temperature of heating, it is possible and preferable to impart the desired crimp without imparting excessive shrinkage or decrease in length of the filaments. However, the temperature employed in the crimping or shrinkage process is preferably selected so that it will be at least as high as the highest temperature or temperatures to which the fabric to be made of the crimped filaments would ordinarily be subjected in subsequent use or cleaning. By so selecting the shrinkage temperature, complete stability of the fabric throughout ordinary usag and cleaning processes is assured.

By starting from filaments which have been stretched to a degree less than one hundred per cent of original length during their manufacture, complete shrinkage is permissible and is consistent with the obtention of the above-stated Woollike properties. In addition, the filaments which have been completely shrunk and fabrics made therefrom are substantially. unaffected by heat through a greater range of temperatures than is the case where' only partial shrinkage is employed. However, by selecting a filament or filaments made of a resin having an inherently high shrinkage temperature well above the temperatures that are encountered during customary use of the fabrics to be made therefrom, the filaments of such resins may be made with any desired degree of stretch and may be crimped with either a complete or a partial shrinkage without encountering the danger that the yarns or fabrics made therefrom will undergo shrinkage in subsequent use. For example, stretched filaments of the chlorinated co-polymers of vinyl acetate and vinyl chloride disclosed in the Lytton and Taylor patent cited above as well as of chlorinated polyvinyl chloride having shrinkage temperaturesof at least,- about 100 C. may be subjected .to heat such as to impart only a partial shrinkage to the filaments. Because of the elevated shrinkage and softening temperature ranges of these resins relative to the corresponding ranges of the unmodified co-polymers, a correspondingly higher temperature must be employed in order to effect the desired crimping.

, While temperatures between about 70 to 100 C. are suitable for the unchlorinated co-polymers, temperatures ranging from 100 to 200 C. should be employed with the chlorinated polymers and co-polymers having the elevated shrinkage temperatures. v

The crinkling effect is obtained regardless of whether or not the filaments in the bundle are twisted. However, a certain amount of twist enhances the fiufiiness and crimpiness of the resulting yarn-like structure and imparts additional advantageous characteristics to the resultant product'as pointed out more particularly hereinbelow.

The crimping treatment may also be imparted to yarns made up of several multifilament ends twisted or doubled together to form a plied continuous thread. The several 'ends so doubled may comprise filaments'having the same amount of stretch and made of the same resin or the several ends may comprise filaments, one or more of which may have a different amount of stretch and/or may be made of different resins. The net result of such a combination of filaments having different amounts of stretch and/or of different resins is to enhance the loose and fluffy appearance as well as the crimping and curling of the entire yarn. Upon treating such a combined yarn at a given temperature, at least some of the filaments in the composite yarn may be'given different amounts of shrinkage thereby enhancing the wool-like appearance of the resulting products. The yarn to betreated, whether singles or plied, may have any degree of twist at the time of treatment, but a relatively low twist is preferable. For example, fine yarns preferably have from 0.5 to 4 turns of twist per inch while heavy yarns preferably have 1% to 2 .turns per inch. Where the yarns to be treated are plied of singles yarns having different shrinkage capacities under the conditions of subsequent treatment, the individual singles yarns preferably have different amounts of twist selected to prevent any one or more of the singles yarns from slubbing off those which undergo the greatest shrinkage upon subsequent treatment.

By varying the amount of shrinkage or by varying the denier of the individual filaments of which the filament-bundle or yarn is constituted, it is possible to produce yarn resembling any grade of wool from the coarsest to the finest Shetland. The effects mayfurther be-varied by varying the amount of stretch and controlling the relation between the amount of stretch and the temperature of treatment and either or both of these factors may also be employed in combination with any of the above-mentioned modifications in which several filaments made of different resins or having a different amount of stretch are combined into a composite yarn by doubling with or without an additional amount of twist applied tothe doubled yarn. The single ends of which such plied thread is made may each comprise filaments having the same constitution and the same amount of stretch; or one end comprising only filaments of one resin stretched to a certain extent may be combined with one or more other ends which are made of a different resin or ofthe same resin but stretched to a different degree than the filament in the first end, or each individual end in the composite yarn may comprise a mixture of filaments made of different resins and/or having a different amount of stretch. Furthermore, the individual ends of which the composite yarn is composed may have the same or a different amount of twist and the several ends may be doubled in the composite yarn in such a manner to oppose or favor the snarling tendency of the individual ends resulting from their twist.

Depending upon the character of the initial filament-bundle, the twist therein, the extent of treating and the other factors mentioned above; various forms of yarn-like structures are obtained. In treating a multifilament singles yarn having a relatively low twist, there results in general a yarn-like structure along the length of,

which each filament winds in and out among the remaining filaments so that at one point it may be near the surface of the yarn while at a short distance therefrom it may run more or less deeply within the interior of the yarn. In general, it has been found that the core of the yarn-like structure, whether the yarn is originally twisted or not, has a somewhat lesser crimpiness than the exterior and that the average crimpiness progressively increases from the center to the surface of the structure, which results in a remarkably soft and fluffy exterior. See Figure 2 of the drawing which illustrates this characteristic in;a

' crude way. The reduced crimpiness of the core causes it to resist excessive straightening of the highly crimped filaments upon the exterior when the yarn-like structure is placed under tension. In addition, where a slight or any amount of twist is present in the structure, the several filaments weave in and out within the body of the structure so that each filament has various degrees of crimping along its length depending upon the position it occupies within the body of the structure at the various points, and this structural relationship of the several filaments making up the yarn prevents the external layers from slubbing off the less highly crimped central core of the structure. This novel structure is therefore highly useful in that the fluffy char- Composite or singles yarns may be subjected to the desired temperature to effect shrinkage and crimping as they are wound limply from one I carrier to a second carrier or package. The actual winding of the treated yarn upon the second carrier preferably should not occur untilafter the heated yarn has been allowed to cool so that the bending involved in winding the, yarn upon the carrier will effect a tearing apart of any individual filaments which-mayhave been lightly fused together at points of their surfaces during the heating. For example, the several ends may be plied upon any form of downtwisting equip-,

ment, such as by ring spinning, and the plied yarn may be withdrawn from the package upon which it was wound during plying in such a manner as to allow a loose length to dip limply into and pass through a bath of water heated to the, desired temperature and then the crimped yarn may be wound upon a spool or other package arranged sufi'lciently far from the point of emergence of the yarn from the heating bath to permit it to cool until it loses any tackiness before it is wound upon the spool. Alternatively, the doubled yarn may be put into skein form and may then be subjected to heat by immersion in hot water or by placing it in a heated atmosphere. When the water employed in the treatment is at a relatively high temperature, a rather hard cake is obtained. However, this is readily brokenup by mechanical action, such as by hand kneading, by passing the yarn between pressure rolls or by winding on spools. A softer yarn is produced by immersion of the skein in water of somewhat lower temperature or'in hot air. The hot air treatment produces a bright yarn while the wettreatment causes a dulling of the fibers.

Whereas in the above described procedures heat alone has been employed toshrinkand crimp stretched yarns made from polyvinyl resins it is likewise possible to arrive at the same effect but at lower temperatures with the help of swelling agents for the polyvinyl fibers. In the swollen fibers the contracting forces are released at lower temperatures. Such swelling agents may be liquid or solid chemical compounds,- for instance, ethyl acetate, diethyleneglycol dipropionate, dibutylphthalate, triphenylphosphate or p-dimethwas composed of 54 filaments. It had a total shrinkage capacity of 40%. Four ends of this yarn were doubled with four ends of filaments composed of the same resin but spun only with the stretch due to normal spinning tension, having a titer of 190 denier for 54 filaments and having a shrinkage capacity of only 25%. The plied yarn had a twist of one and one half turns per inch. The yarn was subjected to a bath of hot water at about 90 C., was removed from the bath and was then wound upon a suitable package with a certain amount of mechanical working to soften or loosen the structure. fiuffy and resembled wool.

Example 2 Continuous filaments were wet-spun with 200% The yarn was stretching from a chlorinated co-polymer comprising 90% vinyl chloride and 10% of vinyl acetate having a chlorine content of 60%. ends of such filamentary material were doubled and the doubled yarn was subjected to hot air at 110 C. The resulting yarn was loose and fluffy and had an extremely close resemblance to wool.

Emample 3 was 1:30 by weight. After treatment of the yarn for one half hour at C., the bath was brought to a temperature of 70 C. and the skein was then removed. It had shrunk to a fluffy, woolly yarn.

Example 4 Two ends of a yarn spun from chlorinated polyvinyl chloride and having a shrinkage capacityof at 165 C. and a titer of 250 denier for 50 filaments were doubled with two ends of a similar yarn having a shrinkage capacity of 75% at 165 C. and a titer of 230 denier for 50 filaments.

The plied yarn carried two turns twist per inch. It was immersed for a few minutes in a mixture ylamino benz'aldehyde, phenol, and o-hydroxy- Example 1 A filamentary yarn of a co-polymer comprising 90% of vinyl-chloride and 10% of vinyl acetate was subjected to stretching by leading the yarn about two godet wheels having their circumferential speeds differing by 75% immediately after the filaments left the spinning. tube. The resulting singles yarn had a. titer of 220 denier and consisting of 50 parts per volume of grain alcohol and 50 parts per volume of ethyl acetate. After drying of the treated yarn, it was fiufiy and resembled wool.

The strength and extensibility characteristics of the yarn may be improved by plying singles yarnsof such polymers or co-polymers or their chlorinated derivatives with an end of such materials aswool, cotton, silk, rayon or other synthetic filaments, such as stretched Vinyon, particularly of the chlorinated type, nylon or fiber glass. Furthermore, a yarn may be made by combining in any proportion filaments of the polyvinyl polymers, co-polymers or their chlorinated derivatives with fibers or filaments of other materials, such as wool, cotton, silk, rayon or other synthetic fibers, such as nylon or fiber glass. Preferably, in all these combinations, materials ofcontinuous filaments are employed in order to minimize the danger of itching or scratching by fabrics made of such materials.

The wool-like material produced in accordance with this invention is water-resistant and mothproof; Besides having less tendency to produce an itching or scratchy sensation upon the wearer. the material serves as an excellent substitute for wool, especially for persons who are allergic to wool or similar synthetic wools of proteinous constitution. Besides being adaptable to weaving, fulling, and similar processes, the yarn obtained in accordance with the invention is particularly,

Three adapted for knitting. Because of its softness and reduced tendency to provoke irritation upon the skin of the wearer, fabrics made from thi material are adaptable to the manufacture of infant clothing. When combined with filaments of other materials, cross-dyeing effects may be used with advantage to enhance esthetic appeal. Fab rics made from the wool-like material produced in accordance with this invention are also readily laundered and dry rapidly. The crinkled singles yarns may also be doubled with other yarns to produce special effect yams in manners heretofore known to the art. In the claims the word filamentary is intended to refer to both filaments (continuous lengths) and fibers (short filamentary lengths). The expression "internally stressed is intended to refer to the internal condition acquired by the filamentary material upon being stretched during manufacture as hereinabove described.

The description is intended to be merely illus trative, and various modifications and changes may be made within the spirit and scope of the following claims.

I claim:

1. A yarn structure comprising a plurality of filaments of a polyvinyl resin, the filaments being in a crimped or crinkled condition substantially throughout said structure, the average degree of crimpiness generally increasing from the central to the exterior portions of said structure.

2. A yarn structure comprising a plurality of filaments of a co-polymer of vinyl chloride and vinyl acetate, the filaments being in a crimped or crinkled condition substantially throughout 'said structure, the average degree of crimpiness generally increasing from the central to the exterior portions of said structure.

3. A yarn structure comprising a plurality of filaments of an after-chlorinated polyvinyl resin, the filaments being in a crimped or crinkled condition substantially throughout said structure, the average degree of crimpiness generally increasing from the central to the exterior portions of said structure.

4. A yarn structure comprising a plurality of filaments of a polyvinyl resin twisted together so that the'filaments weave in and out among each other along the length of the structure, the filaments being in a crimped or crinkled condition substantially throughout said structure, the average degree of crimpiness generally increasing from the central to the exterior portions of said structure.

5. A yarn structure comprising a plurality of filaments of a co-polymer of vinyl chloride and viny1 acetate twisted together so that the filaments weave in and out among each other along the length of the structure, the filaments being in a crimped or crinkled condition substantially throughout said structure, the average degree of crimpiness generally increasing from the central to the exterior portions of said structure.

6. A yarn structure comprising a plurality of filaments of an after-chlorinated polyvinyl resin twisted together so that the filaments Weave in and out among each other along the length of the structure, the filaments being in a crimped or crinkled condition substantially throughout said structure, the average degree of .crimpiness generally increasing from the central to the exterior portions of said structure.

7. A yarn structure comprising -a plurality of.

filaments in a crimped or crinkled condition, the average degree of crimpiness generally increasing from the central to the exterior portions of said structure.

KARL HEYMAN'N.

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