US3314845A - Method of flocking and subsequently developing latently crimpable fibers and article produced thereby - Google Patents

Description

Aprll 18, 1967 J PERR| 3,314,845

METHOD OF FLOCKING AND SUBSEQUENTLY DEVELOPING LATENTLY CRIMPABLE FIBERS AND ARTICLE PRODUCED THEREBY Filed July 23, 1964 2 Sheets-Sheet l WFIG1-\\ AB w :25

DB .54 AB RADIUS cuavmuns MAJOR ARC .065 INCH TIP T0 TIP 4 22 IF I00 INVENTOR JOSEPH MARK PERRI BY M ATTORNEY ADHESI LAYER April 18, 1967 w Filed July 23, 1964 BULK CC/G 3, I PS1.

J. M. P METHOD OF FLOCKING AND SUBSEQUENTLY DEVELOPINGLATENTLY CRIMPABLE FIBERS AND ARTICLE PRODUCED THEREBY 2 Sheets-Sheet 2 FIGZ CRIMP FREQUENCY CRIMPS INCH INVENTOR JOSEPH MARK PERRI ATTORNEY United States Patent Ofiiice 314 845 has AND SUBSEQUENTLY DEVELOPING LATENTLY CRIMPABLE Frsnas Joseph Mark Perri, Waynesboro, Va., assignor to E. I. du Pont de Nemours and Company, Wilmington, Del., a corporation of Delaware Filed July 23, 1964, Ser. No. 384,647 16 Claims. (Cl. 161-641) straight fibers owing to certain inherent limitations in the synthetic fibers, e.g. nylon fibers, the resultant products, while often possessing good wear-resisting properties, have been characterized by severa attendant disadvantages. Thus the attainment of a wide factorily flocked on-a commercial scale. In addition, the pile density of typical carpets so produced has been relatively low such that the products have a lean appearance and hence possess poor cover. Still a further disadvantage has been that sustained loads upon the surface of the carpets give rise to imprints which are not readily removed due to the inability of the compressed straight fibers to recover their original position upon removal of the applied force.

Accordingly it is an object of the invention to provide a novel process for preparing flock pile fabrics. An additional object is the attainment of pile fabrics having a superior combination of properties in comparison with flocked fabrics which have heretofore been available. Another object is to provide fabrics having a superior cover and which are composed of synthetic pile fibers. A further object is to provide an improved flocking process for preparing superior suedes, velvets, carpets, furs, blankets, and laminated insulating fabrics. Other objects will be apparent from the description of the invention given below.

In accordance with the present invention there is provided a method for the manufacture of pile fabrics comprising t e steps of providing a plurality of short straight,

which have been treated to temporarily inhibit premature crimp, depositing the th-usly treated fibers upon an adhesive coated backing material to provide a pile layer of upstanding fibers thereon, and treating the resultant fabric to develop the latent crimpability of the fibers.

By the term latently crimpable as used herein to describe thefibrous starting material, it is meant that although the fibers be in a generally straight condition they nevertheless possess an inherent tendency to take on or otherwise assume an irregular contorted configuration by exposure thereof to heat, moisture or other chemicals, or by a combination thereof, without the exertion of a 3,314,845 Patented Apr. 18, 1967 mechanical force upon the fibers to disrupt the otherwise generally straight condition. It is essential that the fibers be capable of derived as products of the above described process, sess an advantageous combination of properties including high bulk and excellent compressional properties and cover. These pile fabrics comprise a synthetic organic polymeric fibers individually and ranfibers and an upper portion occupied by the remaining 50 0 sections of the extended length of said fibers, fiber sections in said support portion being essentially spaced apart, free of crimp, and perpendicularly aligned with fiber sections in said upper portion having ing a pile surface having a random and m-ulti-directional array of fiber sections and fibento-fiber entanglements. These novel pile fabrics will be described in further detail below inconnection with the drawings.

In the above defined pile fabrics the crimped section of the fibers will be seen to possess a curved or curled configuration. In other words such a fiber will trace a direction, eg as shown'in 2, as opposed to many types of mechanically crimped fibers which exhibit an abrupt change in direction, e.g. the well known stutter-box or saw-tooth crimped configuration. Because the flock fibers are of a relatively short length and fixed in the adhesive layer,

1 l H=M circumference 21r-radius The fibrous starting materials employed in the process of the invention are short straight, latently crimpable, synthetic organic polymeric fibers. For most purposes a crimp frequency= polymers or linear addition polymers, for example, acrylonitrile polymers and copolymers; polyarnides, such as polyhexamethylene adipamide, polycaproamide, poly-(metaphenylene isophthalamide), and copolyamides; polyesters such as polypivalolactone, polyethylene terephthala,31a,sas

ate and copolyesters prepared from glycols and terephthalic and isophthalic acids; polyethylene and ethylene copolymers; polypropylene and propylene copolymers; polybenzimidazole; copolymers of acrylonitrile with small amounts of copolymerizable monomers (e.g. with 12% by weight methyl methacrylate or with 10% by weight vinyl acetate); and the like. Each of the synthetic fibers selected for use in accordance with the invention must be prepared under conditions such that a latent capacity to crimp is built into the fiber. Suitable techniques for preparing fibers with latent crimp are described in the following 'U.S. patents and applications: Sisson 2,439,815, Taylor 3,038,237, Breen 3,03 8,236, Zimmerman 3,038,235, Moulds 3,038,239, Kilian 3,050,821, Hebeler 2,604,689, and Olson Serial No. 335,187, filed Jan. 2, 1964. The fibers disclosed in those patents and the application are well suited to the practice of the instant invention.

One suitable fiber having a latent capacity to crimp is a bicomponent acrylic fiber wherein one component of the fiber is composed of polyacrylonitrile and the other component is composed of a copolymer of acrylonitrile with 6 to 20% by weight of vinyl acetate.

A particularly suitable class of short straight, latently crimpable, synthetic organic polymeric fibers can be prepared by cutting short fibers from the composite filaments described and claimed in aforementioned Taylor US. Patent 3,038,237. Among the multi-component fibers described in that patent, a preferred class is represented by those in which each of the two or more components is composed of at least 85% by weight of recurring units derived from acrylonitrile. Especially suitable pile fibers are composed of a bicomponent acrylonitrile polymer fiber in which one side of the fiber is composed of polyacrylonitrile and the other side of the fiber is composed of a copolymer of acrylonitrile with between 1% and 5% of sodium styrene sulfonate. The latent crimpability attributed to the multicomponent fibers of that patent results from the co-spinning, side by side, of two or more selected synthetic materials differing in ionizable content.

In flocking fibers upon an adhesive coated substrate it is important to the achievement of satisfactory appearance and performance properties that the fibers be disposed in an upstanding or generally perpendicular relationship with respect to the substrate. For this reason it is essential that the fibers initially possess a generally straight extended configuration and that such configuration be maintained during the flocking process. Since the flock fibers employed in accordance with the invention have a latent capacity to crimp, it is furthermore essential that they do not become prematurely crimped prior to upstanding adherence to the backing. To temporarily inhibit such undesirable deviation from the essentially straight condition it the fibers, e.g. to rigidify the fibers in a temporary state which can be later removed or otherwise destroyed following the flocking step. The crimp inhibition means may be, for example, a simple operation wherein after spinning, drawing and any subsequent hot wet treatment, the fibers are held tautly in the lengthwise dimension and dried. Of course, fibers may be spun and collected in a normal manner followed at a later time by remoistening and drying in a taut condition. Alternatively the fibers may be coated with by weight or more of a waterrepellent weighting agent, such as paraffin wax or a chlorinated wax.

Because synthetic organic polymeric fibers are normally non-conductive, it is especially desirable that they be treated prior to flocking with an antistatic agent. As is well known in the art the antistatic agents function by imparting a hydrophilic property hence electrical conductivity, to the surface of the synthetic fibers, most of which are relatively hydrophobic in-nature. Both ionic and nonionic substances and mixtures thereof are commonly emis necessary to appropriately treat I ployed for reducing the static attractive forces. Typical antistatic agents which are suitable for treating fibers prior to flocking in accordance with the invention include the condensation products of ethylene oxide with alkyl phenols, e.g. nonyl phenol, or fatty acids, erg. of 12 to 18 atoms. Such products commonly contain between 20 and by weight of ethylene oxide. Other suitable antistatic agents include the pyrophosphonate condensation products of phosphorus pentoxide and fatty acids of 12 to 18 carbon atoms, combinations of the latter acids with cetyl trimethyl ammonium bromide, and triethanolamine oleate.

Since the antistatic agents are usually water soluble and hygroscopic, normally it will be highly desirable to use a so-called separating agent to treat the fibers prior to flocking. The separating agents can be particulate solids which serve to reduce fiber-to-fiber adhesion; that is, they keep the fibers individually suspended while being transported in an electrostatic field. Alternatively, they may be film-forming materials which function to decrease the sliding friction between fibers. The use of separating agents is often desirable in overcoming the tacky or hygroscopic properties often associated with some antistatic agents. There are three classes of separating agents which have been found suitable for use in coating the synthetic fibers employed in the invention. The first type cornprises inorganic particles such as silica, magnesium oxide, aluminum oxide, talc and the like, which are described more fully in Ewing, US. Patent 2,805 ,959. The second class of separating agents found suitable are lubricants and free-flowing powders such as the metallic stearates, including magnesium stearate and aluminum stearate. The third class of suitable separating agents comprises water soluble compounds and polymeric waxes, such as cationic fatty acid amide derivatives, long chain alkyl amines such as octadecyl amine, condensation products of 40 to 90% by weight ethylene oxide with higher alkyl phenols, e.g. nonyl phenol, or with tall oil fatty acids. The separating agents can be applied in the form of powders, solutions or dispersions to the fibers. These agents are advantageously added to the fibers during the. crimp inhibition step; that is, by wetting the tautly held fibers therewith followed by drying in the taut condition and cutting the short fiber lengths. Certain of the wax-like separating agents, e.g. octadecylamine, which envelop the fibers with a film coating are also capable of functioning a a weighing agent, i.e. to prevent premature crimp. The amount of separating agent provided on the surface of the fibers should be between about 0.05 and 15% In general the two types of known methods which may be used for propelling flock against a backing material are (1) the use of an electrostatic field and (2) the use of a heater device. Both are well suited to the practice of the invention although the method involving the use of an electrostatic field is especially preferred. When using an electrostatic field for propelling the synthetic fibers, it is highly desirable to apply to the fibers before flocking not only an antistatic agent but also :a separating agent.

If it is desired to use electrostatic flocking for propelling the fibers to a backing, the suitably conditioned and treated short flock fibers may be distributed by means of a revolving brush or shaking device from a bin over a grid electrode charged with 10,000 to 100,000 volts. At some distance from the grid there is a metal plate-connected to the oppositely charged terminal of the high voltage supply. On this plate rests a backing material covered with a thin adhesive layer. The charged flock is projected toward the ground and impinges upon the adhesive surface in a direction which is generally perpendicular to the backing material. Using this procedure it is possible to make pile fabrics having pile densities as high as 10 pounds per cubic foot and as low as 1 pound per cubic foot,

Normally the flock fibers employed will have a denier ranging from about 3 to 30. As is well known in the flocking to the fiber length to provide cut ends that are clean, not frayed, and do not have stray fibrous hairs as a result of poor cutting.

f it is desired to Suitably treated and cut sieving device proor brushing mechanism to assure of fibers onto a uniformly moving backing fabric traveling below the flock supply device. The backing is supported by a heavy belt which passes over a block rotating at a speed such that the corners bedded in an adhesive spread upon the backing prior to deposition of the flock fibers. Subsequently, vacuum devices are utilized to remove non-adhering flock from the adhering fibers. The excess flock so obtained is recycled by pneumatic devices to the supply chamber.

Any suitable backing material may be used as a base ployed to develop the latent crimp in the pile fibers backing material. Suitable the invention, the latent crimp is preferably developed by treating the pile fabric under hot Wet conditions. Often it is entirely practical to develop the crimp in the pile or to hot and/or wet finishing conditions. If a chemical shrinking agent is used or if other wet conditions are used to develop the crimp, it will be later necessary to dry the pile fabric.

One of the primary advantages of the invention resides in t e provision of a rapid,

ymeric pile fibers. Another important advantage is that the process provides a means for preparing flocked fabrics which have certain properties which are superior to the flocked fabrics containing straight or uncrimped pile fibers. The property advantages of the products made in accordance with the invention include improved aesthetics, more pleasing hand, less bristly fabrics, more wool-like texture, greater cover and bulk, and greater insulating capacity. Another that it readily affords a great number of styling variations in the resultant pile fabrics.

The present invention may be used to prepare flocked pile fabrics which have a wide variety of uses, ample, suedes, velvets, furs, floor covering materials, such as carpets and tiles, blankets, insulating facing cloths, apparel interliners, and various laminated miulti-layer fabrics. One example of a laminated fabric which can be prepared in accordance with the invention comprises a backing material to which is attached a flocked pile layer and finally a top cloth which is adhered by means of an adhesive to the surface of the pile. This type of structure is especially suitable as an insulation lining for wearing apparel. Another example of a suitable laminated fabric is one in which an adhesive is applied to the bottom surface of a backing material containing'on the opposite surface a flocked pile layer as produced by the invention. Following the application of a support cloth to the adhesive a layer of straight, non-latently crimpable flock is applied to the adhesive such that the fibers of the second pile layer are perpendicular to the support cloth. Optionally, another backing material might then be applied by means of an adhesive to the exposed surface of the straight flocked pile. An addition involves the application of a separate layer of flocked latently crimpable fibers to each side of a backing cloth, followed by development of the crimp. A double faced article of such a structure is especially suited to the formation of blankets. A modification 1 i straight, non-latently cri mpable flocked fibers between two sheets of support cloths. A wide variety of such structural modifications will be apparent.

The flocked pile fabrics of the invention can also be advantageously used to prepare tufted fabrics, e.g. by passing the tufting threads through the flocked pile layer and into attachment with the backing. In this way the flocked pile layer forms a background for the tufts so as to offer pleasing aesthetics and permit a reduction in a plurality of such fibers all adhered in upstanding relationship with respect to a common base, the effect would be to create two superposed layers or portions, each coextensive with the adhesive In the upper portion the fibers sections would all be crimped and bent over. Moreover, because the fiber spaced apart, parallel, and, of course, dicular to the base. Although these two portions of the pile would contain equal Weights of fiber, the lower would of considerably less pile den sity. The unique nature of this pile configuration is illustrated in FIGURE 2 which shows schematically the representation of fibers in a sample of a product of the invention.

It is a surprising and highly advantageous feature of the products of the invention that maximum bulk is achieved at a comparatively low crimp frequency. Thus as shown in FIGURE 3, at -a load of 3.1 p.s.i. a pile layer attains a maximum bulk at 2 crimps per inch (c.p.i). Normally, the crim-ped portion of the fibers will have an average crimp frequency of 1 to 8 c.p.i. to give a suitably high bulk, e.g. of at least 10 cc./gra-m at 3.1 psi. load. These findings in connection with the products of the invention are in marked contrast to the prior art where heretofore it had been found that the higher the crimp frequency of a fiber, the greater will be the bulk of a pile fabric produced therefrom.

Referring once again to FIGURE 1, the ratio of the extended fiber length AB to the effective length of the crimped fiber CB is defined as a constant K. The radius of curvature of a circle drawn using the major are or curved surface of the crimped section of the fiber is designated as r, which is equal to the distance CD in the relaxed state. The angle P is the angle subtending the arc of the circle forming a curved part of the crimped section of the fiber. The circumference c in inches is the circumference of the circle whose radius of curvature is r such that equals 21rr. Also the crimp frequency in crimps per inch of the fiber is simply the reciprocail of the circumference of the circle having a radius of curvature r. Hence, the ratio CD/DB may be defined as the ratio of the radius of curvature of the crimped section of the fiber to the length of the un crimped portion of the fiber when relaxed. The pile fabrics of the invention will preferably have a K value in the range of 1.1 to 1.7, a ratio CD/DB between 0.95 and 0.15, and the upper 50% portion of the pile will have a pile density at least 1.5 times that of the lower 50% portion.

The high resistance to compression provided by the products of the invention arises owing to the optimum frequency of the crimp and to the confinement of that crimp in the upper portion of the pile layer. Thus straight pile fibers (no crimp) in a fabric are acted upon individually, hence buckle rapidly under compressive forces. As the crimp level of a fiber of given length increases, e.g. at 2 c.p.i. as illustrated in FIGURE 3 in connection with fit inch flock of 20 denier, there de velop two structural factors important to resistance to buckling. The first of these is the decreased slenderness (shorter hence more rigid nature) of the supporting columns and the manner in which the ends are essentially permanently fixed (one end in adhesive, the other by fiber to-fiber entanglements). Secondly, the crimped fiber sections in the upper portion of the pile layer become entangled to form a high density matrix which distributes stress laterally in absorbing loading energy. When the crimp frequency becomes excessively high, the supporting sections of the fibers become buckled, as a result the density of the upper and lower portions become nearly equal and, since support will be then derived mainly from interfiber friction at the fiber contact points, overall bulk is reduced. It will be understood from the above that the optimum bulk to be developed in a sample will depend upon the radius of curvature of the major arc of the crimp, the extended fiber length, and of course the ratio CD/DB.

Although the novel pile fabrics of the invention have been described especially in connection with a flocking process, it is to be understood that other methods may be used for their preparation.

The following tests are used in connection with the novel products of the invention.

Measurement of crimp frequency v Pile fibers in a fabric are sheared off at the glue line, distributed over a glass plate and photographed. Twentyfive fibers were examined at random measuring the radius of a circle drawn through the major curvature of the fiber. The crimp frequency (c.p.i.) was calculated using the equation:

l c.p.i. with the value used for r being the average radius for the fibers so examined.

Pile fabric compression test Specimens measuring 4" x 4" are taken from pile fabric samples to be tested. Two specimens are normally taken from each sample and the data reported are the average of results from both. The specimens are conditioned in two steps according to common textile testing procedures wherein a preconditioning at 130i10 F. in moving air from a minimum of two hours is followed by a final conditioning at RH and F. in moving air for a minimum of sixteen hours. The conditioned specimens are weighed to the nearest 0.01 gram and measured to the nearest 0.02 inch taking an average of three measurements in both length and width.

Each specimen mounted on a compression cell is subjected to compression with pile side up at the rate of 0.2 inch/ minute on an Instron Tester using a circular presser foot of 10 infl.

The load cycling controls of the tester are set so as to cause the crosshead to return when the desired full load has been applied. In the case of carpets of high denier fiber (12-25 d.p.f.), a maximum load of 10 p.s.i. is used; Whereas for fleeces and lower denier fiber (2-12 d.p.f.), the maximum load is 1.1 psi. The crosshead stops when the pressure has returned to zero. After a two minute interval a second compression cycle is run in the same manner. Following the second cycle of compression and unloading, the specimen is taken from the tester and the pile is sheared off as evenly and cleanly as possible from the surface of the adhesive using heavy duty barber clippers equipped with a No. 000 (fine) clipper head. The sheared backing is then weighted to the nearest 0.1 gram. The sheared backing is subjected to compression testing in the same manner as in the unsheared form except that it is loaded at a rate of 0.1 inch/minute crosshead speed. During the compression test the stress is recorded and appears on the chart as a pen line whose coordinates are stress in lbs. and separation between cell and presser foot in inches. From this graphic data, specific points can be extracted. On the first compression cycle, a specific point of interest is the cell presser foot separation when the presser foot barely touches the sample and the pressure starts to increase. This separation is used as the initial thickness of the specimen. From this second cycle and its record, the integrator count for the load portion of the cycle is obtained.

Specific volume or bulk The specific volume or bulk of the pile layer at given load is calculated as the volume of the pile at the given load divided by the pile weight. The pile volume at the given load is determined from the second compression cycle as the difference between the thickness of the pile fabric and the backing at the given load times the speci men area, suitable conversion factors being applied.

The following examples illustrate specific embodiments of this invention without intending to limit the scope of the invention. All parts are expressed by weight unless otherwise indicated.

EXAMPLE I A continuous filament yarn (1000 denier, 140 filaments) was spun from bicomponent filaments (100% acrylonitrile polymer and acrylonitrile/ 5 sodium styrene sulfonate copolymer) in accordance with Taylor Water m1 1280 Antistatic agent A g 0.16 Sodium sulfate cg 3.20 Antistatic agent B 2 .g 1.28 Acetic acid g 0.16 Malachite green dye g 0.256 Red dye g 0.672

Aqueous solution containing 2-1nethy1-2,4-penta11e diol and 60% condensation product of oleyl alcohol and ethylene oxide (1 mol ratio).

Cm-Czs fatty alcohol plus cetyl trimethyl ammonium bromide (50/50).

3 [2-(p-[2 chloro-l-nitrophenylazo]-N-ethylanllino)ethyl] trimethylammonium chloride. 7

After one and one-half hours at the boil, the temperature was then lowered to 80 C. and there was added 4.8 g. of a separating agent comprising a cationic fatty acid amide derivative (Ceranine HC). The frame was removed from the bath and without rinsing the fibers were allowed to dry in the taut condition. The frame and its dyed fibers were then submitted to dry heat at 130 C. for 10 minutes, thus setting the fiber in a straight condifrom the frame and tion. The fiber was then removed cut by means of a paper cutter into flock /s-inch in The flock so prepared was free-running and had no in a container. The

The flock was placed in a 3 inch transparent acrylic plastic basket, approximately 4 inches long, one side of which was a As-inch mesh metal screen which served as a posithe ground plate. The flocking cage was then shaken in such a manner to allow the flock to fall onto the adhesive surface at a potential of 18,000 volts. This was continued until an additional shaking did not produce any further increase in pile density. The scrim fabric was then removed and placed in an oven at 90 C. for about /z-hour to cure the adhesive. The excess flock was removed and the fabric was then treated with atmospheric steam for a short time to develop the crimp of the bicomponent fiber. By comparison to unsteam-treated flock it was evident that a very dense curly, bulky structure was obtained via the steaming treatment, quite different from the normal straight chenille-type pile structure otherwise obtained with non-latently crimpable flock. By coating the opposite side of a previously flocked surface, a second side could then be flocked with the same self-crimping bicomponent fiber to give a good blanket-like fabric approximately /s-inch in thickness after steaming.

EXAMPLE II A 2,000 denier, 200 filament, drawn yarn from the same bicomponent filaments as used in Example I, was wound on a frame in the same manner as in Example I, and treated at the boil in a bath made according to the same formula as in Example I. However, after heat setting, this fiber was cut on a guillotine-type paper cutter I0 A fabric prepared according to the same procedure as used in the earlier example was mately 20,000-38,000 volts was used. After achieving the highest possible density as could be obtained by repeatedly shaking the container holding the straight flock over the adhesive scrim fabric, the fabric was allowed to dry and thereafter exposed to atmospheric steam. The resulting fabric had a thickness of approximately 0.122 inch of which approximately 0.10 inch was due to the bulked fiber flock on the surface. Then a similar fabric was prepared using a t'arred backing fabric, the density 2.37 pounds/cu. ft. at

surface resembling a fine mohair furniture upholstery covering and was suitable for a rug, blanket or upholstery fabric.

EXAMPLE III hour:

Water ml 3520 Antistatic agent A (of Example I) g 0.4 Antistatic agent B (of Example I) g 3.2 Sodium sulfate g 8.0 Acetic acid g 0.4 Separating agent (of Example I) g 12.0

The fiber was then air dried while taut on the frame, unwound, and then cut into 4;" lengths using a guillotine cutter. The flock was then placed in a Waring Blendor with 2.5% of Alon C (A1 0 and mixed thoroughly. This coating provided for easy fiber separation in the flocking process. The fiber was then placed in an electromil layer of a polyurethane adhesive to achieve a pile density corresponding to 1.25 lbs. per cu. ft. The flocked fabric was placed in an oven at C. to cure the adhesive. Atmospheric steam was played upon the pile as an insulating liner for jackets, and in bed spreads or upholstery fabrics. The performance of fabrics composed of fibers crimped in this manner is particularly notable because (1) high cover is achieved with a minimum of fiber content, and (2) warmth is achieved in a light weight fabric. As an example of case 1), the appearance of the fabric prior to crimp development was lean; that is, the fibers were observed as individuals and provided a minimum of cover owing to their perpendicular orientation with respect to the surface. After crimping, however, the fibers became intimately associated with one another developing continuity in the pile surface to provide cover. The stiffness of individual fibers is considerably altered as a result y of crimp development to provide a soft hand in contrast to the bristly hand of uncrimped fibrous pile layers.

The improved insulating value of the crirnped fiber pile structure over those of straight fibers results from fiber intermingling to decrease convection, the cells so formed limit the circulation of air In use, a 2-pound a higher voltage, approxiof the composite filaments in the form A blanket comprised of fabric containing post-crimped flock provides comparable warmth to a 3-pound commercial woven blanket and has an added advantage of increasing sleeping comfort because of the decreased weight.

acrylic polymer adhesive to yield a flocked fabric having a pile fiber density of 6.5 ounces per square yard. The adhesive was cured at 149 C. At this stage the pile fibers had no crimp and wereperpendicular along their 5 full lengths to the adhesive line. The pile fabric was EXAMPLE 1V then subjected to the action of atmospheric steam for Flock of Vii-inch length Was P p y cutting one-half minute to permit crimp development of the denier bicomponent filaments of the composition as debhwmponent fib and then d d at 71 C f 15 i scribed in Example I. utes. The resulting fabric showed a high degree of Ten Pounds of flock P p was loaded into a 10 resistance to compression and had characteristics that StOCk dye ktIl6 With hOt water being added, simultanewould make it suitable for use as a carpet, An examinaously as an aid in Packing the fiber tightly- A y 50111- tion of the compression characteristics through a range tion with the following composition was circulated through f 1() i using Instron Compression T f carpets the stock at a temperature of 95l00 C. for one hour: h w d it to hav a high work-to-compress (Wc=.544 Water 25 5 m le/in?) wherein We is the work per unit area re- Red dye (of Example I) "pounds" 02 quired t3 compress the carpet sample to psi. ind ca- Antistatic agent (of Example I) (H tive of bounce, and a high bulk value (15.8 cc./g. at Acetic acid (H 3.1 p.S.1.). The crimp frequency was found to be 2.4 Antistafic agent B (of Example I) 0 4 c.p.i. Examinat on of thepile structure (FIGURE 1) led to the following description: Following the one-hour dye treatment, the bath was Essentially each fiber had one end fixed in the glue allowed to co l to 60 and o Pound P ectadecyla' line from which it extended vertically for a distance of mine was added as a separatlng and welghtlng agent 54% of its length, then bent to define an arc subtended After further cooling to 30 C. the excess liquor was by an angle p of 0 The tip to tip angle was and drained off and the dyed flock was dried inatumble dryer 25 the ratio of the extended fiber length to pile height at 105 C. The fl particles were separated by g a (AB/BC) was 1.25. The ratio of the radius of curvathl'ollgh a Series of'sefeens m- At thls Stage ture to the straight portion was 0.49. By actual count the Particles had i1 Waxlike Coating whleh Served to there were 8500 fibers per square inch. The distance Strain Premature p development Whlch would between fiber axes averaged 0.011 in. for the 20 denier i e occur on drying. The fl Was then placed m (2 mil diameter) fibers used; the curved portion of the an electr st flock applicator Charged to 20,000 voltsfiber extended horizontally to cover a distance equal to The applicator Was Shaken to discharge the flock thfeugh that occupied by 8 fibers. The fiber density of the upper its Screen aperture Onto 3 Previously P p cotton 50% of the structure was calculated to be 1.64 times that scrim whose surface was coated with a 10-mil layer of f the lower 5 There was a density gradient Within a Polyurethane adhesive Solution T flOCk Was thus the upper 50% and the density increased toward the surdirected to form a pil l y havlhg a denslioy of face, the maximum being achieved, in the region where Y The febnc was then fined at for the horizontal component of fiber direction is greatest. one-half hour to cure the adhesive. In this state, the The fieeked erimped fiber of this example according P fibers were Straight and Onenmd perpendlculafly to FIGURE 1 had the following structural parameters: to the scrim backing. In order to produce a fabric of radius of curvature r is K is DB is O 14ineh. pleasing hand as desired for apparel use, the fabric was CD/DB is 9; and DB/AB is 5 i rinsed in warm water, C., to remove the crimp re- 7 straining waxlike coating. The fabric was then dried EXAMPLES VI-VIII at 70 C., whereu on the crimp of the two-component fiber developed and the desired soft hand was achieved. ggigg flocked iabncs were prePal-ed from the position of bicomponent acrylic fibers as used The fabnc was Wen suited for the manufacture of m in Example V The flocking conditions were varied 2: 63:85 hners for Jackets baby blankets and upholstery however, to yield products having properties as indicated EXAMPLE v in Tables I and II. Examples VI and VII illustrate the 50 preparation of fabrics having desirable properties in ac- A tow of 20 denier continuous filaments was spu cordance with this invention, whereas Example VIII from a bicomponent composition'of 100% l i iie illustrates the preparation of a fabric outside the scope polymer on one side of the filament and 96% acryloniof the invention because the crimp frequency is too high. mile/4% sodium styrene sulfonate copolyrner on the The products of Examples VI and VII are especially other side of the filament in accordance with Taylor suitable as paint roller covers.

TABLE I Example L eii git h il bgl ifii Fr iiii e ri cy, E2? p i e s t(i 16 c.p.i. 3.1 p.s.i.) (in.-1bs./in.

i0 .23 2.8 1.8 16.9 .643 20 .25 10 .23 212i 313 id 1221 US. 3,038,237. The tow was wrapped on a frame so 65 TABLE II that the ends of the filaments were held taut while the tow was passed through a bath of a 4% by weight aqueous solution of cetyl pyridinium chloride. Excess solution was squeezed from the tow by passage through nip rolls and the tow was dried at 80 C. The filaments contained 1% by weight, based on the weight of the fibers, of cetyl pyridinium chloride. The dried tow was then cut into flock particles 6 millimeters in length. The cut fiber was then flocked by electrostatic means as described in Example I onto a cotton fabric coated with an Fiber Parameter Ex.VI i Ex.VII Ex.VIII

. I15 0. l2 0. l0

In order to show the effect of difierent treatment conditions for developing the latent crimp in the fibers after crimping, a series of flocked fabrics was prepared similar to that described in Example V,

TABLE III Crimp Frequency, Steam Exposure Time 0.5 min. 15 mins, c.p.i.

Sultanate in Copolyrner Fiber Denier course, depend upon the nature of the end use.

What is claimed is:

1. Method for the manufacture of pile fabrics comprising the steps of providing a plurality of short straight,

adhesive coated backing material.

6. Method of claim 1 wherein the latent crimpability of the fibers is developed by hot wet processing conditions.

7. Method of claim 1 component fibers.

3. Method of claim 7 wherein the said multi-component fibers have at least two components wherein each is composed of an acrylonitrile polymer.

9. Method of claim 7 wherein the said multicompowherein the said fibers are multi- 10. A pile fabric comprising a plurality of short synthetic organic polymeric fibers individually and randomly attached in entanglements.

11. Fabric of claim 10 wherein said fibers are multicomponent fibers.

12. Fabric of claim 11 wherein the said multi-component fibers have at least two components wherein each is composed of an acrylonitrile polymer.

13. A pile fabric comprising a in said support portion.

14. Fabric of claim 13: wherein said fibers are of essentially uniform extended length, said length being about 0.1 to 0.35 inch.

15. Fabric of claim 13 wherein CB is short fibers in crimped form.

References Cited by the Examiner UNITED STATES PATENTS 2,439,815 4/1948 Sisson 161177 2,776,223 1/1957 Brown et al. 11717 3,024,518 3/1962 Newton 161-66 X 3,038,235 6/1962 Zimmerman 161177 X 3,038,237 6/1962 Taylor 161-177 X 3,203,821 8/1965 Domin 117-17 ALEXANDER WYMAN, Primary Examiner. EARL M. BERGERT, R. H. CRISS,

Assistant Examiners.

Claims (1)

10. A PILE FABRIC COMPRISING A PLURALITY OF SHORT SYNTHETIC ORGANIC JPOLYMERIC FIBERS INDIVIDUALLY AND RANDOMLY ATTACHED IN GENERALLY UPSTANDING RELATIONSHIP TO AN ADHESIVE LAYER, THE PILE FORMED OF SAID FIBERS COMPRISING A SUPPORT PORTION OCCUPIED BY THE LOWER 50% SECTIONS OF THE EXTENDED LENGTH OF SAID FIBERS AND AN UPPER PORTION OCCUPIED BY THE REMAINING 50% SECTINS OF THE EXTENDED LENGTH OF SAID FIBERS, FIBER SECTIONS IN SAID SUPPORT PORTION BEING ESSENTIALLY SPACED APART, FREE OF CRIMP, AND PERPENDICULARLY ALIGNED WITH RESPECT TO SAID ADHESIVE LAYER, FIBER SECTIONS IN SAID UPPER PORTION HAVING AN AVERAGE CRIMP FREQUENCY OF 1 TO 8 CRIMPS PER INCH THEREBY CRREATING A JPILE SURFACE HAVING A RANDOM AND MULTIDIRECTIONAL ARRAY OF FIBER SECTIONS AND FIBER-TO-FIBER ENTANGLEMENTS.

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