US 3707746 A
A process for forming pile structures comprising the forming filamentary pile loops and securing the base of the loops to a nonwoven backing material by impinging the material with liquid streams to entangle the fibers. The resultant unitary structure is formed without requiring the use of adhesive bonding, has excellent strip tensile strength and tuft pull out strength, and is useful in conventional pile-fabric end-uses, e.g., carpets.
Description (OCR text may contain errors)
f States Patent 1191 1111 3,707,746
Summers 1 1 Jan. 2, 1973 [541 PROCESS OF PREPARING A TUFTED 2,706,324 4 1955 Cogovan ..16l/65 PRODUCT 2,810,950 10/1957 Rice ..l6l/65 2,913,803 11/1959 Dodds ..16l/65 [751 Invent: Rmald Summers wflmmgmn, 3,019,508 2/1962 Reinhardt et a1.... ..161/66 DBL 3,285,796 11 1966 McElhinney ....l6l/66  Assignee, E. I. d Pomde Nemours and Com 3,485,7Q6 12/1969 Evans ..l6l/72 pally Wilmington DeL 3,493,462 2/1970 Bunting et al. l6l/169 Filed: June 3, 1971 Primary ExaminerRobert F. Burnett  APPL 149,846 Assistant Exami nerRoger L. May
Att0rney-N0rr1s E. Ruckm'an Related [1.8. Application Data  Division of Ser. No. 853,633, Aug. 28, 1969, aban-  ABSTRACT A process for forming pile structures comprising the forming filamentary pile loops and securing the base ggfi i fig gg fg8; of the loops to a nonwoven backing material by impinging the material with liquid streams to entangle  F'eld of searchwzsln 23 2 7 the fibers. The resultant unitary structure is formed without requiring the use of adhesive bonding, has excellent strip tensile strength and tuft pull out strength,  References cued and is useful in conventional pile-fabric end-uses, e.g.,
UNITED STATES PATENTS p 2,398,645 4/1946 Kahn ..16l/65 X 11 Claims, 3 Drawing Figures PATENTEDmz 191a 3.707. 7'46 INVENTOR RONALD J. SUMMERS ATTORNEY PROCESS OF PREPARING A TUFTED PRODUCT REFERENCE TO RELATED APPLICATION This is a division of application Ser. No. 853,633 filed Aug. 28, 1969 and now abandoned.
BACKGROUND OF THE INVENTION This invention relates to nonwoven fabrics made from textile fibers. More specifically, it is concerned with a process for preparing nonwoven pile fabric.
The term pile is used generally in the art, as well as herein, to mean single continuous filaments, yarns of continuous filaments, yarns of spun staple fibers and long staple fibers which extend out from the fabric a distance of 2 mm. or more in the form of loops or short segments of fibers (i.e., a sheared pile). Tufted pile fabrics are conventionally made by pushing loops of a continuous yarn through a backing fabric with tufting needles and securing the pile to the backing with an adhesive. Such processes require relatively expensive tufting yarns of good quality and require a critical adhesive bonding step in order that the pile will not pull out during use. The resin used in the bonding may interfere with dye uniformity and the uniformity of the appearance of the pile structure. Since the backing fabric and pile yarn are of different compositions, it is very difficult to obtain the same dye receptivity on both parts and the backing may be visible through the pile.
Processes eliminating tufting by forming pile loops on a temporary carrier and then bonding the base of the loops with a plastic bonding material have been suggested by Beasley, U.S. Pat. No. 3,157,554 and Guinard, U.S. Pat. No. 3,173,823.
fibers of loop-connecting segments; the fibers turning, winding, twisting back and forth and passing about one another and about fibers of the loop-connecting seg ments in the three dimensions of the backing to provide coherency and strength to the structures. The structure has a strip tensile strength of about 5 lbs./in. to about lbs./in. and the loops have a tuft pull out strength of at least about 1.0 lbs. preferably 5 to 9 lbs. or higher. This pull out strength is particularly significant, in that conventional tufted structures normally have much lower values (e.g., between about 0.2 and 0.6 pounds) prior to adhesive bonding (latexing).
DRAWINGS The invention is illustrated with reference to the drawings.
SUMMARY OF THE INVENTION The present invention provides a novel process for making pile structure from a pile-forming filamentary material and aseparate nonwoven filamentary backing material, without requiring adhesive bonding of the pile. The process is capable of higher speeds than the usual tufting operations and enables one to use relatively inexpensive pile fibers and/or also wider selection of pile fibers and backing fibers than otherprocesses.
The process comprises the steps:
a. forcing segments of a pile-forming filamentary material into a pile-forming carrier to provide loops connected to adjacent loops by the remaining filamentary material segments,
b. placing a backing material upon the carrier and against the loop connecting segments to provide an array,
c. treating the array with liquid streams impinging upon the backing material to entangle the fibers of backing material with one another and with the fibers of the loop-connecting segments, and
d. removing the resulting unitary pile structure from the carrier and drying it.
This novel pile structure, also provided by this invention, comprises the pile-forming filamentary material and the nonwoven filamentary backing materiabThe pile-forming filamentary material is looped back and forth to define loops extending from at least one side of the backing and loop-connecting segments extending into the backing. The fibers of the backing material are randomly entangled with one another and with the FIG. 1 is a cross-sectional view of a product of the invention.
FIGS. 2 and 3 are cross-sectional views of apparatus to make single and double-faced pile fabrics respectively.
In FIG. 1 is seen the pile l with pile loops 4 and loopconnecting segments 3. The entangled nonwoven filamentary backing material 2 is interentangled with the fibers of the loop-connecting segments 3.
In FIG. 2 a pile-forming material 1 is placed on the pile-forming carrier 5 and is forced into aperture 6 to form pile loops 4 by pushing means 7. Tensioning means 8 is used to prevent pulling out the pile loops 4. A fibrous backing web 9 is placed on top of the assembly and secured to the pile with hydraulic jet 10.
FIG. 3 shows two pile-forming carriers 5 in the form of drums which cooperate to give a double-faced pile fabric.
DESCRIPTION OF THE PREFERRED EMBODIMENTS All manner of fibers and fiber structure can be used for the pile-forming filamentary material. They should be long enough to provide at least one pile loop and one loop-connecting segment; thus staple length fibers can be used of about 3 (7.6 cm.) to 6 inches (15 cm.) or longer. A web of staple fibers having sufficient integrity for handling is suitable. Continuous length fiber structures such as yarns spun of staple fiber, twisted yarns of continuous filaments or separate continuous filaments are preferred. The process is especially advantageous in that tows (large bundles of fibers with little or no twist) of continuous filaments can be used by spreading each bundle out into a thin layer or web on the pile-forming carrier.
The pile-forming carrier contains apertures or open pockets in spaced relation to any desired arrangement or pattern. The aperture may be a slot that extends the width of the carrier, e.g., in a grating, or may be a cell of a honeycomb or the like.
The fibers can be pushed into the apertures of the pile-forming carrier by bars as for a slot, or mechanical fingers as for closed cells. Mechanical devices for this purpose, as well as suitable gratings, are taught in U.S. Pat. No. 3,157,554, issued Nov. 17, 1964 to Beasley, U.S. Pat. No. 3,173,823, issued Mar. 16, 1965 to Guinard, and British Pat. No. 1,055,121, published Jan. 18, 1967.
Fluid jets may also be used to form the loops in the apertures. These jets may be the same fluid jets (described hereinafter) used for entangling. Briefly, the orifices may have a diameter of from about 0.003 to about 0.05 inch and should be closely spaced, e.g., from 10 to 40 or more per inch to give the effect of a sheet or curtain of fluid. A pressure of from 20 to 2,000 psi gauge may be used depending upon the speed of the pile-forming carrier as it is moved under the jets and the weight of the fibers being fonned into loops.
The nonwoven filamentary backing material can be made of any type or length of fiber. Randomly disposed webs or carded webs of staple length fibers are preferred. Any denier fiber can be used but the lower deniers such as 0.5 to 3 dpf are more readily entangled. Warp sheets or web of continuous filaments, webs of random filaments prepared by direct laydown of extruded filaments as shown in British Pat. No. 932,482 granted Nov. 20, 1963, or staple webs containing continuous filaments can be used. Reinforcing scrims, woven or nonwoven, can be used in the backing (see Example 6). It is preferred that the backing material have a basis weight within the range of about 2 to 10 ounces/ydfi, although higher or lower basis weights may be used.
The fibers of the backing material and the connecting loops of the pile are interentangled to secure the fibers and pile into an integral, strong fabric by treating with fine liquid streams issuing from orifices at high pressures as taught in US. Pat. Nos. 3,434,188 and 3,403,862. Suitable orifices will have diameters of about 0.003 to 0.030 inches (0.076-0.76 mm.) in diameter and are preferably spaced about 0.01 to 0.1 inch (0.25 to 2.5 mm.) apart in rows. Suitable orifices give essentially columnar streams, i.e., having a total divergence angle of not greater than about The orifices are located from about 0 to cm. above the fibrous material.
The amount of treatment must be sufficient and is measured by the energy expended per pound of fabric produced. The energy (E,) expended during one passage under a manifold in the preparation of a given nonwoven fabric, in horsepower-hours per pound of backing web (HP-hrs./lb.), may be calculated from the formula:
E =0.l25 (YPG/sb) where: Y number of orifices per linear inch of manifold,
P= pressure of liquid in the manifold in psig.,
G volumetric flow in cu.ft./min./orifice,
s speed of passage of the web under the streams, in
b the weight of the backing web, in oz./yd.".
The total amount of energy (E) expended in treating the web is the sum of the individual energy values for each pass under each manifold, if there is more than one.
In general at least about 0.25 HP-hr./lb. is required to make the products of this invention and preferably at least 0.5, most preferably at least about 1.0. Preferably at least 90 percent of the total energy is obtained at pressures of 500 psi. (35 kg./cm.') or greater. It must be understood that the energy requirements to make a given quality product vary widely with the nature of the backing material. With all other conditions being equal, the energy needed to make well-entangled products is greater for 66-nylon than for cotton, rayon or polyester fibers, and is less for 66-nylon than for acrylic fibers and polypropylene fibers. Using the same fiber composition and length, fibers of small denier are more readily entangled than higher denier fibers. Using the same fiber composition and denier, shorter fibers are more readily entangled than longer fibers. Using the same fiber composition, denier and length, fibers having greater crimp frequency and amplitude of crimp are entangled more readily than less crimped fibers. In addition to these differences, it is to be understood that, with a given web, the energy requirements to obtain a desired level of entanglement will depend upon the nature of the patterning plate or other support.
The pile loops of the entangled product may be cut if desired to yield a cut-pile fabric or a combination of cut and uncut.
The product can be shrunk to increase fiber density (see Example l-B), dyed, or given other fabric treatments as desired. Particularly, the product can be coated on the back with latex or other binders to increase stiffness and strength. Although such a coating is not necessary herein, it is preferred because of the improved properties it provides (see Examples l-A and 1-B, with and without latex).
The pile and backing fibers may also differ in shrink age or latent crimp to vary the density of the pile structure on the face of the carpet or the density or compliance of the backing.
A preferred product consists of a nonwoven fabric with pile on both faces secured to an intermediate backing as in Example IV.
MEASUREMENTS AND TESTS Samples used for tensile tests and measurement of fabric weight are conditioned at 70 F. (21 C.) and 65 percent relative humidity for at least 24 hours before testing under these conditions.
Strip tensile strength and elongations are measured on 2-inch breaking lengths of 1 inch width (5 X 2.5 cm.) at an elongation of 50 percent per minute on an lnstron testing machine. The strip tensile strength in pounds/inch (kilograms/centimeter), herein designated as lbs./in. (kg/cm.) is the average for samples cut from the fabric at degrees to each other.
Tuft pull out strength is a measure of the force required to separate the individual pile tufts from their backing. The test procedure described in ASTM Standard D-l335-60T is used herein with the modification that the specimen is held by a clamp without the tube in the loop of the specimen.
EXAMPLES The following examples illustrate particular embodiments of the present invention.
EXAMPLE 1 This example illustrates the preparation of pile fabrics according to this invention utilizing gratings as pile-forming carriers, and mechanical means to form the pile loops.
A warp with 10 yarns per inch (per 2.54 cm.) is made from a spun yarn, 2 ply 9 cotton count of 8.5 denier per filament (dpf) acrylic staple. The warp is laid across a grating made of parallel metal rods 0.062 X 0.31 inch (1.6 X 7.9 mm.) with rounded edges spaced seven per inch (per 2.54 cm.) with the narrow edges forming the face of the grating. The warp is pushed down in the slot of the grating by a blade such as described in U.S. Pat. No. 3,173,823, which is held in position until the succeeding row of loops has been formed when it is removed.
A random web with a weight of 4 ounces/square yard (oz./yd. (136 grams/square meter) of 1.5 inch (3.8 cm.), 1.5 dpf polyester staple is placed on top of grating containing the pile warp and the entire assembly passed at 1 yard/minute (0.9 mpm) under a rowof fine streams of water from a row of orifices about 7% inch (12 mm.) above the top of the web. The orifices have an upper cylindrical section of 0.007 inch (0.18 mm.) diameter with a lower frustoconical section as an exit and are spaced per inch (per 2.54 cm.). The composite is given one treatment each using 800, 1,200 and 1,500 psi (56, 84 and 105 kg./cm. pressure for a total energy of treatment of about 2.1 HP-hrs./lb. of backing web. The product is removed from the grating and dried.
The product (A) has a weight of 28.5 oz./yd (970 g./m. with a pile height of 0.31 inches (7.9 mm.), a strip tensile strength of about 12 lb./in. (2.1 kg./cm.), an elongation at the break of about 57 percent and a tuft pull out force of 5.8 lbs.
Another product (B) is made using the above process but using a backing web of a high shrinking polyester staple (shrinks about 40 percent at 100 C.) and forming a more dense pile. After the hydraulic treatment the fabric is treated with steam which causes about 20 area shrinkage. The final product has a weight of 26 oz./yd. (880 g./m. with a 0.38 inch (9.7 mm.) high pile, a strip tensile strength of about 15 lb./in. (2.7 kgJcm.) and a tuft pull out force of 9.8 lbs. Product (B) has an improved appearance over product When about 15 percent by weight of a latex coating is applied .to the backing of samples of products (A) and (B) above, the tuft pull out increases to 12.7 and 14.8 lbs., respectively.
EXAMPLE 2 This example further illustrates the preparation of pile fabrics. The general procedure of Example 1A is repeated with the following exceptions.
A tow of 2 dpf continuous, acrylic filaments is evenly spread transverse to the rods in a grating to form the pile loops. The grating is made of parallel rectangular rods 0.033 X 0.25 inch (0.84 X 6.4 mm.) spaced six per inch (per 2.54 cm.) with narrow edges forming the face of the grating. The web of Example 1-A with a weight of 3 oz./yd. (102 g./m.'*) is used as a backing. The composite is passed under the water streams at 1.5 ypm (1.37 mpm) using pressures of 600, 1,000 and 1,200 psi (42, 70 and 87.5 kgJcm?) to give a total energy of 1.9 HP-hrsJlb. of backing web.
The dried product has a weight of 17.1 oz./yd. (580 g./m.) with 0.2 inch (5 mm.) pile height, a strip tensile strength of 14 lb./in. (2.5 kg./cm.) and an elongation of about 65 percent.
EXAMPLE 3 A tow of 12 dpf continuous filament of nylon is used to form pile loops as in Example 1 but with the rods of the pile-forming carrier spaced 5/inch (per 2.54 cm.). The web of Example 1-B is placed on the carrier and the fibers entangled using the procedure of Example l-A and one treatment at each of 600, 1,000, 1,500 and 1,500 psi (42, 70, 105 and 105 kg./cm. to give a total energy of treatment of 4.3 HP-hrs./lb. of backing web.
The product (A) is removed from the carrier, shrunk with steam and dried. It has a weight of 24 oz./yd. (820 g./m. a pile height of 0.31 inch (7.9 mm.) and a breaking strength of 18 lb./in. (3.2 kg./cm.). A portion of the fabric is coated on the back side with a commercial latex to increase the stiffness and strength of the fabric. The coated fabric has a weight of about 27 oz./yd. (920 g./m. and a strip tensile strength of 26 lb./in. (4.7 kg./cm.).
A sculptured pile fabric with alternating sections of different height pile in a row is made by using a piledepressing blade having 0.37 inch (9.4 mm.) long slots 0.19 inch (4.8 mm.) deep alternating along the bottom of the blade to provide different lengths of pile loops in the slot of the pile-forming carrier.
EXAMPLE 4 A second pile-forming carrier, as above, is covered with tow, pile loops are formed and the blades are withdrawn. This assembly is placed on top of the first assembly so that the connecting loops of both piles contact the central staple web and the gratings in the upper and lower carriers are parallel and offset, i.e., a rod in the upper carrier sits in the middle of a pocket in the lower carrier. The complete assembly is then passed at 1 ypm (0.9 mpm) under streams of water for one treatment each at 100, 300, 700 and 700 psi (7, 21, 49 and 49 kg./cm. for a total treatment energy of about 2.2 l-lP-hrsJlb. of staple web, using the jets of Example 1-A. The carriers are removed from the double-faced pile fabric, the fabric treated with steam to give about 20 percent area shrinkage and the fabric dried.
The product is a strong, coherent, soft fabric with the appearance of a terry cloth and having a weight of about 9.7 oz./yd. (330 g./m.).
EXAMPLE 5 This example illustrates the use of liquid jets as the forcing means to provide the pile loops.
A sheet of aluminum honeycomb having cells 0.18 inches (4.7 mm.) deep with a hexagon cell diagonal of 0.186 inch (4.7 mm.) resting on a X 100 mesh screen is used as the pile-forming carrier.
The honeycomb is covered with a warp of a nylon continuous filament yarn of 3,700 total denier for the 204 filaments. The warp-covered carrier is then passed under a row of water streams while tensioning the ends of the yarn sufficiently to permit pile loop formation in the cells by the water streams. A row of 0.005 inch (0.127 mm.) diameter orifices spaced 40 per inch (per 2.54 cm.) is used.
The honeycomb bearing the pile loops is covered with a 2 oz./yd. (68 g./m. random web of 1.5 dpf rayon staple fibers and passed at l ypm (0.91 under the above water streams at 1,200 psi (84 kg./cm. for two treatments for a total energy of about 3 l-lP-hrs./lb. of random web used.
The dried product of 14.5 oz./yd. (490 g./m. weight has the appearance and handle of a soft pile carpet with a pile height of about 0.12 inches (3 mm.).
EXAMPLE 6 This example illustrates the use of a nonwoven backing web reinforced with a woven scrim.
A random web 18 dpf, 3 inch (7.6 cm.) nylon staple of 6 oz./yd. (200 g./m. weight is entangled by passing at 4 ypd (3.6 mpm) under the water streams of Example 1 at 1,000 psi (70 kg./cm. while supported on a 80 X 80 mesh screen. This treatment of 0.1 HP-hrs./lbs. gives the web some integrity for handling.
The above lightly entangled web is placed on a pileforming carrier consisting of a grating of parallel wires, about 0.1 inch (2.5 mm.) in diameter placed in a frame at a frequency of 5 per inch (per 2.54 cm.). Pile loops are formed by passing at 0.5 ypm (0.46 mpm) the web and carrier under the water streams of Example 1 at 750 psi (53 kg./cm.
A fibrous backing web consisting of two 1 oz./yd. (34 g./m. random webs of rayon staple with a woven nylon scrim (about X 14 mesh) of 1.2 oz./yd. (41 g./m. in the center is placed on the carrier and given two entangling treatments with the above water streams at 1,200 psi (84 kg./cm. for a total energy of about 5 l-lP-hrs./lb. of backing web.
The final product is a strong, soft pile fabric with a pile height of 0.125 inches (3.2 mm.) and a weight of 13.5 oz./yd. (460 g./m.
What is claimed is:
l. A process for making unitary pile structures of pile-forming filamentary material and a separate backing of nonwoven filamentary backing material which comprises a. forcing segments of said pile-forming filamentary material under tension into a pile-forming carrier having apertures to provide loops of the material, each of said loops being connected to adjacent loops by the remaining segments of the filamentary material;
b. placing said backing material upon said carrier and against the loop connecting segments to provide an array of said materials;
c. treating said array with penetrating streams of liquid from jet devices arranged to impinge on the side of the backing material opposite to that of the carrier to entangle the fibers of said backing material with one another and with the fibers in said loop-connecting segments to provide a strong backing and to secure the loops to said backing, said liquid being jetted from closely spaced orifices 0.002 inch to 0.030 inch in diameter which are supplied with liquid at a pressure of at least 200 pounds per square inch gauge to provide a total treatment of at least 0.25 l-lP-hr./lb. of backing material; and then (1. removing the unitary pile structure product from said pile-forming carrier and drying it.
2. The process as in claim 1 wherein said pile-forming filamentary material is selected from the group consisting of tow, continuous filament yarn, spun yarn, and webs of staple fibers having a length of at least equal to twice the loop length.
3. The process as in claim 1 wherein said portions of said pile-forming filamentary material are forced into said apertures of said pile-forming carrier by mechanical means.
4. The process as in claim 1 wherein said segments of said pile-forming filamentary material are forced into said apertures of said pile-forming carrier by fluid means.
5. The process as in claim 1 wherein said pressure is at least 500 pounds per square inch gauge and said total treatment is at least 0.5 HP-hr./lb. of backing material.
6. The process as in claim 1 wherein said backing material comprises staple fibers.
7. The process of preparing a tufted product as defined in claim 1 wherein said backing material in step (b) is of a highly shrinkable fibrous material and the pile structure after removal from the carrier is given an after-treatment to shrink the highly shrinkable fibers forming the backing to provide a structure having a dense pile.
8. The process as in claim 1 wherein said pile-forming segments are forced into the apertures of said pileforrning carrier to varying depths to provide a predetermined pile pattern.
9. The process as in claim 1 wherein in step (a) said segments of the pile-forming filamentary material are forced into a pile-forming carrier having a honeycomb network of apertures to provide a structure having discrete tufts of loops.
10. The process as in claim 1 wherein in step (a) said segments of said pile-forming filamentary material are forced into a pile-forming carrier having a plurality of longitudinally spaced apertures to provide longitudinally spaced rows of loops.
11. A process for making unitary double-faced pile structures of pile-forming filamentary material and a separate backing of non woven filamentary backing material which comprises a. forcing segments of a first pile-forming filamentary material under tension into a first pile-forming carrier having apertures to provide a first network of loops of the material, each of said loops being connected to adjacent loops by the remaining segments of the filamentary material;
. forcing segments of a second pile-forrning filamentary material under tension into a second pileforming carrier having voids defining loops to provide a second network of loops of the material, each of said loops being connected to adjacent loops by the remaining segments of the filamentary material;
. placing said backing material upon said first carrier and against said loop connecting segments;
cl. placing the second carrier containing the second network of loops against said backing material on a side opposite to that of said first carrier with said loop connecting segments contacting said backing material to form an array, said first network of loops being arranged in a staggered positional relationship with respect to said second network of loops by arranging the first and second carriers to misalign the voids of each carrier with respect to the voids of the other carrier;
e. treating the array with penetrating streams of liquid from jet devices arranged to impinge on each side of the backing material to entangle the fibers of said backing material with one another removing the resulting product from the carriers and drying it to form the unitary pile structure.