US3620003A - Novelty yarn and method of forming same - Google Patents

Abstract

A NOVELTY SINGLES YARN COMPRISING FIBRILLATED POLYMERIC STAPLE FIBRES AND NON-FIBRILLATED STAPLE FIBRES, CHARACTERIZED IN THAT MOST OF THE FIBRILLATED POLYMERIC STAPLE FIBRES STAY ON THE PERIPHERY OF THE YARN TO FORM A SHELL SURROUNDING THE NON-FIBRILLATED STAPLE FIBRES. A NOVELTY CARPET IS MADE FROM SAID YARN. THE PROCESS OF MAKING A NOVELTY YARN MADE UP OF FIBRILLATED POLYMERIC STAPLE FIBRES AND NON-FIBRILLATED STAPLE FIBRES, COMPRISING: (A) BLENDING STAPLES OF AT LEAST ONE FIBRILLATED POLYMERIC STAPLE FIBRE WITH STAPLES OF AT LEAST ONE NON-FIBRILLATED SYNTHETIC, OR NATURAL FIBRE, (B) CARDING THE SAID BLEND INTO A SILVER, (C) DRAFTING AND SPINNING THE SILVER TO FORM A YARN HAVING FIBRILLATED POLYMERIC STAPLE FIBRES MOSTLY EMERGING OUT ON THE PERIPHERY OF THE SAID YARN AS A SHELL SURROUNDING THE OTHER FILAMENTS OR FIBRES WHICH FORM A CORE.

Description

United States Patent 01 fice 3,020,003 Patented Nov. 16, 1971 3,620,003 NOVELTY YARN AND METHOD OF FORMING SAME Sohinger Nath Chopra, Hawkesbury, Ontario, Canada,

assignor to Chemcell Limited, Montreal, Quebec, Canada No Drawing. Filed Feb. 11, 1970, Ser. No. 10,633

Int. Cl. D02g 3/04, 3/34 US. Cl. S7140 13 Claims ABSTRACT OF THE DISCLOSURE A novelty singles yarn comprising fibrillated polymeric staple fibres and non-fibrillated staple fibres, characterized in that most of the fibrillated polymeric staple fibres stay on the periphery of the yarn to form a shell surrounding the non-fibrillated staple fibres. A novelty carpet is made from said yarn.

The process of making a novelty yarn made up of fibrillated polymeric staple fibres and non-fibrillated staple fibres, comprising:

(a) blending staples of at least one fibrillated polymeric staple fibre with staples of at least one non-fibrillated synthetic, or natural fibre,

(b) carding the said blend into a sliver,

(c) drafting and spinning the sliver to form a yarn having fibrillated polymeric staple fibres mostly emerging out on the periphery of the said yarn as a shell surrounding the other filaments or fibres which form a core.

This invention relates to a novelty yarn obtained by spinning a blend of staple fibres, a portion of said staple fibres being fibrillated polymeric fibres, and to a process of making said novelty yarn.

As it well known, yarns can be made from natural fibres or by the extrusion of polymeric materials into filaments of fibres which are cut into staples, carded, drafted, and twisted or spun into yarns. The yarns may be Woven, knitted or tufted into fabrics, carpets, etc.

Broadly stated, it has now unexpectedly been found that when fibrillated polymeric fibres are cut into staples, blended with non-fibrillated fibre staples, carded, drafted and twisted or spun into a yarn, the result is a novelty singles yarn comprising fibrillated polymeric fibres and non-fibrillated staple fibres characterized in that most of the fibrillated polymeric staples stay on the periphery of the yarn to form a shell surrounding the non-fibrillated staple fibres. The fibrillated polymeric fibres generally have fiat surfaces which render the yarn lustrous. Also, the resulting yarn generally has a knubby appearance as will be seen further on.

The irregularities in the fibrillated fibres, their coarse size, their stiffness, or reduced flexibility, make them of an unusual nature. As a result, these fibres stick out when they are spun with other filaments. This sticking out effect appears to be due to the stiffness and the bigger and irregular size of the fibrillated fibres as compared to non-fibrillated staple fibres which have a regular and smaller cross-section and which are more easily pliable. The irregularity in cross-sections of the fibrillated fibres may also enhance this sticking out effect.

With this shell effect:

(1) event a small percentage of fibrillated fibres may be added to other non-fibrillated fibres to yield effects and properties somewhat similar to those characterizing the fibrillated fibres;

(2) cheaper fibres or filaments could be enclosed inside as a filler and still maintain the influence of the fibrillated fibres;

(3) good abrasion resistance may be obtained from a blend of fibrillated fibres of good abrasion resistance with non-fibrillated fibres of poor abrasion resistance;

(4) the appearance of a manufactured article made from a blend as defined in (3), remains over an extended period without any noticeable change;

(5 the contribution of the fibrillated fibres to the color of the finished product is generally quite out of proportion to its weight ratio;

(6) the change in color due to wear is generally much reduced if the fibrillated polymeric fibres are highly abrasion resistant irrespective of the filler;

(7) the cross-section of the fibrillated fibres, their fiat nature gives a unique appearance and hand to the blended yarn, products resulting thereof at no additional cost;

(8) the knubby nature generally encountered with fibrillated polymeric fibres give a unique appearance and hand of the blended yarn.

For instance, with fibrillated polpropylene yarn:

(a) a small percentage of staples of fibrillated polypropylene added to staples of other fibres could deliver some effects and properties of fibrillated polypropylene yarn;

(b) a cheaper filler fibre, for instance acetate, could be enclosed inside the yarn and still maintain the influence of the fibrillated polypropylene staples, as will be seen in the examples.

By fibrillated fibres, are meant those which are generally produced by a process which consists of producing an extrudate from a mixture comprising a molten polymer and a foaming agent which is or evolves gas at extrusion temperature and then generally drawing the extrudate subsequent to extrusion. The molten extrudate is preferably hot-melt drawn or attenuated at temperatures above the glass transition temperature of the polymeric material. After stretching of the hot melt attenuated product, it is preferred to orient the polymer and thereby produce increased strength. The product may also be crimped and heat relaxed, if desired. The melt, in addition to containing a foaming agent, may also contain a coloring component, that is to say, the extrudate may be a dope-dyed extrudate.

The present invention is applicable to all thermoplastic resins which can be fabricated by melt extrusion. Suitable resins include one or more polymers and/or copolymers of materials such as polyethylene, polypropylene, polybutene, polymethyl-S-butene, polystryrene; polyamides such as polyhexamethylene adipamide and polycaprolactam; acrylic resins such as polymethylmethacrylate and methyl methacrylate; polyethers such as polyoxymethylene; halogenated polymers such as polyvinyl chloride, polyvinylidene chloride, tetrafluoroethylene, hexafluoropropylene, polyurethanes; cellulose esters of acetic acid propionic acid, butyric acid and the like; polycarbonate resins and polyacetal resins. Resins which have been found to be especially suitable for use in conjunction with the present invention are polyethylene and polypropylene.

The foaming agents which are useful in the extrusion of foam are known. As previously indicated, solids or liquids which vaporize or decompose into gaseous products at the extrusion temperatures, as well as volatile liquids, may be employed. Solids which are suitably employed in the process of the present invention include azoisobutyric dinitrile, diazomino benzene, 1,3 bis (pxenyl) triazine azodicarbonamide and similar azo compounds which decompose at temperatures below the extrusion temperature of the foaming composition. Commonly used solid foaming agent producing either nitrogen or carbon dioxide include sodium bicarbonate and oleic acid, ammonium carbonate and mixtures of ammonium carbonate and sodium nitrile. Volatile liquids which are suitable foaming agents include acetone, methyl ethyl ketone, water, ethyl acetate, methyl chloride, ethyl chloride, methylene bromide and, in general, fluorine containing normally liquid volatile hydrocarbons. Foaming agents which are the normally gaseous compounds such as nitrogen, carbon dioxide, ammonia, methane, ethane, propane, ethylene, propylene and gaseous halogenated hydrocarbons, are also desirable. A particularly preferred class of foaming agents are fiuorinated hydrocarbon compounds having from 1 to 4 carbon atoms which, in addition to hydrogen and fluorine, may also contain chlorine and bromine. Examples of such blowing agents are:

dichlorodifiuoromethane; dichlorofiuorornethane; chlorofiuoromethane difluoromethane; chloropentafluoroethane; 1,2-dichlorotetrafluoroethane; 1,1-dichlorotetrafluoroethane;

1, 1 ,2-trichlorotrifiuoroethane; 1,1,1-trichlorotrifluroethane; 2-chloro-1,1,1-trifluoroethane; 2-chloro-1,1,12,-tetrafluoroethane; l-chloro-1,1,2,2-tetrafluoroethane; 1,2-dichloro-1,1,Z-trifluoroethane; 1-chloro-1,1,2-trifiuoroethane; l-chloro-1,1-difluoroethane; perfluorocyclobutane; perfluoropropane; 1,1,1-trifluoropropane; l-fiuoropropane;

1, 1, 1 ,2,2-pentafluoro propane;

1,1, 1,3-pentafiuoropane;

1 1,1,2,3,3-hexafiuoropropane;

1,1 l-trifluoro-3-chloropropane; trifiuoromethylethylene; perfluoropropane, and perfiuorocyclobutene.

The quantity of foaming agent employed will vary with the density of foam desired-a lower density requiring a greater amount of foaming agentthe nature of the thermoplastic resin foamed and the foaming agent employed. In general, the concentration of the foaming agent will be from 0.0015 lb. per 100 lbs. Of the thermoplastic resln.

Fibrillated products prepared by the hot melt attenuation technique contain very irregular individual fibrils, the cross-sections of which are also very irregular in shape and size. It should also be noted that within the same fibril there will be a plurality of geometrically different cross-sections generally sticking together as a flat stiff yarn, and having an appearance of cut and uncut film. The fibrillated product may be extruded in sheet or film form and subsequently worked by means of suitable mechanical agitations including fluid jets such as air jets, so as to produce bulking and residual fibrillation. The filmforming die is preferably such as to have an opening thickness of about .005 inch to .060 inch. When polypropylene is being extruded, it is preferred that the die have an opening thickness of from .02 inch to .04 inch. The splitting of the film is very irregular and produces hairiness. The fibrillated yarn prepared in this manner may be formulated into a yarn by cutting it in staples and blending them with other staple fibres by means of any of the well-known spinning techniques. The fibrillated products in staple forms have also generally, for the most part, fibrils bigger in size than non-fibrillated staples.

In general, any non-fibrillated fibres may be cut into staples and blended with the fibrillated polymeric staple fibres. These non-fibrillated fibres may be selected from the classes consisting of natural fibres, of animal source such as cashmere, alpaca, wool; or of natural fibres of vegetable source such as cotton; of modified fibres; and

of man-made or synthetic fibres. These non-fibrillated fibres generally have a regular cross-section and are easily bendable and relatively much smaller in size, or finer than the fibrillated fibres. They are also inexpensive when their function is to act as filler.

SIZE OF THE STAPLES Depending upon the use intended for the staples and the system used for the manufacture of yarns, these are generally between 1.5-6 inch lengths, and preferably 3.5- 4.5 inches for the woolen system, bearing in mind that while the shorter staples produce bulkier yarn, the longer staples produce a rougher yarn, having a reduced tendency to pilling. With longer staples, the fibrillated polymer staples have a greater tendency to stay on the periphery of the yarn. The staple fibres are carded, drafted and spun into yarn, as is well known, using the wool, the worsted, the American or other spinning systems. For instance, the woolen system is generally used with 3-5 inch staples, the worsted system with 3-4 inch staples, and the American system with about 67 inch staples. The resulting yarn may then be used to make novelty fabrics, carpets and the like.

The drafting depends upon the denier desired for the finished yarn. The amount of twist may be for instance, in

order of 2 or 3 S or Z turns per inch but this appears to be not critical.

If polypropylene staples are used the fibre agglomerates at the surface of the fabric are reduced because of the polypropylene filaments have a lower breaking tenacity.

When fibrillated polypropylene staple fibres are blended with staples having low abrasion resistance, such as cellulose acetate, the Wear resistance of the latter is generally increased.

The proportion of the fibrillated staples to non-fibrillated staples may vary within a wide range. Generally between 5 to may be used, preferably 15 to 40%. A yarn containing over 30% fibrillated staples generally yields a yarn having good tensile strength depending on the fibre blend. If a higher novelty effect is desired, this percentage may be increased, but if a higher tensile strength is desired, this percentage is generally decreased.

If desired, several kinds of fibrillated polymeric staple fibres and of non-fibrillated staple fibres may be used to make a novelty yarn in which the fibrillated staples generally emerge on its surface.

Although round filaments of non-fibrillated staple fibres are generally used, other non-conventional types of yarns may also be used in the form of staples.

The fibrillated filaments may be crimped. The crimping operation may be conducted with stuffer box crimpers. In the case of fibrillated polypropylene fibres, the crimping operation may be conducted at room temperature. If desired, other means of crimping the filaments, such as gear crimping, may be used.

The filaments may also be subjected to heat treatment. For instance, polypropylene filaments may generally be subjected to a heat treatment at a temperature between about C. and 140 C. under relaxed conditions. The heat treatment may be applied while the filaments are in the crimped tow form immediately after crimping or after the tow has been cut into staples. The heat treatment is generally brought about with ovens or heated rollers such as conveyors or apron-type horizontal ovens. The heating time required for imparting the desired properties to the fibre ranged from about one second at 140 C. to about two seconds at C. If the heat treatment is applied after crimping, the tenacity is generally about the same as when the treatment is applied without crimping.

The yarn may be woven, knitted, or tufted into fabrics, carpets, etc.

The following example will now serve to illustrate the particular embodiments of the invention.

Example 1 Isotactic polypropylene, containing about 1% of oxalic ently about a third of that from 100% Trilan carpets. These results are shown in Table II.

acid, and 0.5% of a commercial green pigment sold by TABLE 11 Imperial Colour under the trade-name Phthalogreen, oompamtiveabmsion was extruded into a ribbon. The ribbon was heat stretched resistance 1 at a temperature between 100 C. and 120 C. The draw- Time Umbra. T 100% Trp i r ti a 2 5 sion cycle (hr.) carpet lan carpet The green fibrillated polypropylene yarn obtained was 14 crimped in a stuffer box to 8 crimps per inch and cut to g 60 4 /2" lengths. This staple which consisted of bundles of 10 5g inter-entangled fibres, was then opened on a cotton card. 36 2 120 The opened fibrillated polypropylene staples were blended 60 by weight into an 18 d.p.f., 4 /2 long turquoise 1Loss efweightinlgrains. Trilan (melt spun triacetate) staple. The physical propzwom tothe backmg erties of these fibres, before and after blending, are 15 The abrasion cycle was continued. After 7 hours the given in Table I. 100% Trilan carpet was worn down to the backing. The

TABLE I Tenacity, Elongation, Toughness, Denier g./d. percent g.crn./d. cm.

001% Fibrillated polypropylene tow 1, 200 1. 3 0. 25 100% Trilan tow s, 431 0.8 22 0.13 15/85 Fibrillated polypropylene Trilan 8, 416 0.85 23 0. 15

The blend was spun on woolen system into 1-0 cotton 25 abrasion test was continued up to 15 hours on the blend count yarn of 5.5 2 t.p.i. twist and made into a threecarpet, the backing was not visible even then. ply yarn of 3.5 5 t.p.i. cable twist. The finished yarn The embodiments of the invention in which an excluhad green colour and novel knubby appearance. sive property or privilege is claimed are defined as A similar yarn was prepared from 100% Trilan fibre follows: for comparison in carpet form. 1. A novelty singles yarn comprising fibrillated poly- Both the 100% Trilan and th blend y rns Were tufted meric staple fibres and non-fibrillated staple fibres, charinto identical carpets of 2.5 lbs./ square yard pile Weight. acterized in that most of the fibrillated polymeric staple The following piling test considered to be a very stringent fibres stay on the periphery of the yarn to form a shell measure of pilling propensity, showed no pilling on either Surrounding th -fib ill t d t l fib carpet. 2. The yarn as defined in claim 1 wherein the fibril- Pilling test lated polymeric staple fibres are stiffer and, on the average, coarser than the nonfibrillated staple fibres, the fibrils The carpet Samples were cut Into speclmens about 8 of said fibrillated polymeric staple fibres having geosquare. Two such carpet squares were stapled together metrically difierent cross section& back to back with a p1ece of cardboard between them to 40 The yam as defined in claim 1 which is knubby act as a stiffener and prevent curling. Stapler used was in appearance Bosiitch Model C usingstaples having 1/2 inch 8- 4. The yarn as defined in claim 1 which is lustrous.

as 1 air through the drum. A Norge Model AE-620 was used. ggi if polymeric stap 1e fibres consist of Polypropylene This machine had a ilion-perforated drum in which air 40 The yam as defined in claim 2 wherein the enters at the b and eaves at the from 9 drum dlam' fibrillated staple fibres consist of cellulose acetate staple eter was 29 inches and the speed of rotation 40 rpm. fibres The regular door was replaced with one made of clear plastic to permit observation of the tumbling. The time The yam as defined clalm 2 Wherem the switch was replaced with a toggle on-ofi switch. The drier fibr1llated Staple fibres 9 of wool Staple fibresdrum was also loaded with the following items: 8. The process of making a novelty singles yarn made up of fibr1llated ploymerlc staple fibres and non-fibrillated 30 strips of natural rubber sheet (Durometer A hardness Staph; fib Comprising;

flbfbllt X 5% X %2") (a) blending of at least one fibrillated polymeric staple 5 SHIPS 0f neoprene sheefl(Durometer A hardnFSS about fibre with staples of at least one non-fibrillated fibre,

50) (17 4 x 5% x /8 Each neoprene strip has 20 Synthetic or natural fibre; to 30 one-inch diameter holes cut 1nto it to 1ncrease the (b) carding the said blend into a sliver; snagging YP of (c) drafting and spinning the sliver to form a yarn balls of tlghtly Toned cotton rags 1n having fibrillated polymeric staple fibres mostly emerg- 3 lbs. ing out on the periphery of the said yarn as a shell surhi l d hi h i h about 20 lb was h t bl d rounding the other filaments or fibres which form a core. for 10 hours. In the laboratory tests, 10 hours in the 9. The process as defined in claim 8 wherein the said tumbler tester has been accepted as approximately the fibrillated polymeric staple fibres consist of polypropylene equivalent of 32,000 trafiic level in floor testing. fib

At the end of the tumbling period, the samples were 10 The process as defined in claim 8 wherein the removed, unstapled, the edges trimmed and bevelled, and the Surface brushed g y to remove loose lint and to non-lfibglated staple fibres consist of cellulose acetate erect the pills. Stap e The most remarkable results were however obtained The process as defined.m clalm 8 whermn the fibr1llated staple fibres consist of wool fibres. from an abrasion test where the samples of 100% Trilan 12 A l 1 f fi and fibrillated polypropylene blend carpets were worn Came? compnsmg move ty Smg es Y 0 bn out by mechanical rubbing action and loss in Weight lated polymeric staple fibres and non-fibr1llated staple of the carpet was measured every half hour. The fibrillated Charactenzed that most f the fibr1llated Poly propylene blend carpet showed a spectacular resistance to Inerlc Staple fibres y 011 the P P 'Y of the Y abrasion, the loss in weight in this case being consistform a shell surrounding the non-fibrillated staple fibres.

References Cited UNITED STATES PATENTS Petitmerrnet 5714O Weiss 57140 Rasmussen 57-157 10 Moler 57140 8 Battista 28-1 Greene 281 Laureti 57144 Scruggs l 57-144 X Rasmussen 28--1 Wada et al. 57144 57l57 R, 157 BY U.S. Cl. X.R.