US 3257264 A
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June 21, 1966 v. H. SCHEUERMAN 3,257,264
NEEDLE-PUNCHED BATTING OF POLYESTER STAPLE FIBERS Filed Oct. 10, 1965 F l G 1 E mum on OTHER WED OPENED WEB OPENING DEVICE FIBER cnoss LAPPER F l G. 2
INVENTOR VERNAL HARDY SCHEUERMAN BY M ATTORNEY United States Patent D NEEDLE-PUNCHED BATTING F POLYESTER STAPLE FIBERS Vernal Hardy Scheuerman, Wilmington, Del., assignor to E. I. du Pont de Nemours and Company, Wilmington, Del., a corporation of Delaware Filed Oct. 10, 1963, Ser. No. 315,213 2 Claims. (Cl. 161-154) This invention relates to stufiing materials, particularly to needle-punched batts of heavy-denier-per-filament polyester staple fibers and to a process for preparing a needlepunched structure.
Needle-punching of loose batts of fibers is Well known to the art. The fiber batts are needle-punched to impart to the batts the properties that mechanical entangling and interlocking of fibers provide, and to increase the strength of the batts. Needle-punching, as practiced by the art, has been concerned with uniformly compacted structures. It has now been discovered that a unitary batt having nonuniform compactness can be prepared by needlepunching and that such structures are markedly superior to conventional structures for certain end-uses.
According to this invention, there is provided a process comprising feeding a loose fibrous batt of polyester staple fibers having a denier per filament of at least about 15, needling the batt so as to prevent all of the barbs from completely penetrating the batt, to produce. a unitary stratified batt having a density of about 1.4 to about 2.9, preferably between 1.6 to 1.8 pounds per cubic foot.
The product of this invention is a unitary stratified batting highly suitable as a cushioning material for upholstered furniture. The product consists of two layers differing markedly in densityof the layers. One layer, comprising the major portion of the batt thickness, has a density of about 1.8 to about 3.5, preferably between 2.8 and 3.0 pounds per cubic foot. The other layer has a density of about 0.9 to about 1.5, preferably between 1.0 and 1.2 pounds per cubic foot. There is a reasonably well-defined line of demarcation between the two layers and, while there is a slight density gradient Within the layers, the density changes Within each layer are small. As a consequence of the dual-density character of this product, it is markedly superior to cross-lapped batts and conventionally needled structures. The fibers of the dense layer of the batt are firmly locked together giving the batt high dimensional stability and thus improving its ease of handling compared to the same material which has not been needle-punched. More importantly, the dense layer provides the batt with the property of effectively masking the springs, edge wires, and the wooden frames, etc., of upholstered furniture, while the non-needled structure shifts at stress-points. The low density layer provides surface softness and loft. The loft, or filling power, of the low density layer permits the cushions and backs etc., of upholstered furniture to be filled with a minimum 'of material while providing the full, luxuriousappearance required for upholstered furniture. Further, the dual nature of these batts provide optimum compressibility and resilience since the batt compresses readily under force, but with increasing resistance. Thus, these batts have neither the harsh,'boardy feel resulting from a high density structure, nor the soft, mushy feel of a low-density product.
In accordance with the process of this invention, the batts just described are prepared by a single pass of a batt of loose fibers through a needle loom. The unitary nature of the dual-density batts is highly advantageous, it being neither necessary nor desirable to prepare a com posite structure of two or more elements. In addition, no supporting or reinforcing element is required; i.e., the use of a chemical bonding agent or a backing such as cheesecloth or burlap, to strengthen or to provide a base to which the fibers are locked, is not needed.
Patented June 21, 1966 The batting of this invention may be constructed of any suitable staple fiber such as those of polyacrylonitrile, polyester, rayon, and nylon. The most useful products are obtained when polyester staple fibers are employed, as polyester fibers are highly resilient and unaffected by moisture.
The staple fibers range in length from about 2 to about 6 inches; preferably, the fiber length is from 2 to 4.5 inches. It is necessary that the staple fibers be crimped for optimum interlocking of the fibers. The fiber crimp should be between 2 and 15 crimps per inch; preferably, the fibers have between 4 and 10 crimps per inch.
In order to obtain the product of this invention, it has been found, surprisingly, that the stable fibers must have a denier per filament of at least about 15. Low deniers of about 5.0 denier per filament arenot suitable for the practice of this invention. Loose fibrous batts of low denier-per-filament fibers are not readily converted to dual-density structures by needle-punching, and, where a dual-density structure is achieved by using relatively high needle penetrations, they do not approach the required density range. Deniers greater than about 75 are difficult to produce economically because of quenching problems associated with their manufacture and, further, are diflicult to crimp. Therefore, in practicing this invention it is preferred to use fibers having a denier per filament of about 15 to 75 and more preferably between 25 and 45.
The loose fiber batts used in the practice of this invention are prepared in any suitable manner. For example, the fibers may be passed through a garnet or card and the resulting web cross-lapped to the desired thickness in a manner known to the art. Alternatively, they may be produced by depositing the fibers from a fluid stream onto a suitable support suchas a screen. When using a garnet, the web is cross-lapped to'give a batting weight of 9 to 40preferably, 13 to 36--ounces per square yard. Due to the inherent characteristics of garnet operation, these batts have a density of about 0.7 to 0.8 for all fiber deniers.
The batting is then sent one pass through' a needle loom fitted with a plurality of conventional-barb needles. The number of needles in the needle board, the frequency of the reciprocating stroke, and the advance of the batting through the needle loom are adjusted to give about 10 to about 80, preferably 20 to 40 penetrations per square inch. The number of penetrations per inch is dependent on the denier per filament of the fibers. In general, the higher the denier per filament of. fibers, the
lower will be the penetrations per inch in order to obtain products with the optimum density characteristics. For example, a loose batt consisting of fibers having a denier per filament of 37 gives a structure whose properties are mediocre at penetrations per square inch and a highly unsuitable structure at the relatively high'level of penetrations per square inch. In comparison, a loose batt of 18 denier per filament fibers gives an unacceptable structure at 30 penetrations per square inch and an excellent structure at about 80 penetrations per square inch.
The depth of needle penetration is critical. It is essential that the needle be inserted into the loose fiber batt so that not all of the barbs, and preferably less than one-half of the barbs, of the needle pass all the way through the batt. Excessive penetration of the barbs of the needle results in the loss of the dual-density characteristic of the batts of this invention.
In the drawings, which illustrate specific embodiments of the invention,
FIGURE 1 is a diagrammatic representation of the process described above wherein baled staple fibers are opened into a web, cross-lapped to form a loose batt of the desired weight and fed through a needle loom to form the stratified batting of this invention. The needle Example I Polyethylene terephthalate staple fibers having a length of 3 inches and about 5 c-rimps per inch and the denier shown in Table I are passed through a garnet and crosslapped to a batt thickness of about 4 inches. The loose fibrous batts thus prepared are then given one pass through a needle loom so as to give about 30 penetrations per square inch. The needles have a -gauge shank, an IS-gauge step-down, and a -gauge blade. The blade is of equilateral triangular cross-section. Each of the three edges of the blade has three notched barbs. The first barb is 0.25 inch from the tip of the blade, and the restv of the barbs are so staggered that there is one barb every 0.083 inch further up the blade. Thus, if the needle is vdriven into the batt so that 1 inch protrudes, the barb furthermost from the tip will have just penetrated through the batt. In this example, needle penetration is adjusted so that 0.35 inch of the needle blade protrudes from the batt. The resulting batts have the characteristics shown in Table I. 1
TABLE I Denier .I 4. l 18 28 37 Density, lbs/cu. lt.:
Batt 0. 83 1. 21 1. 59 2. 38 Lower Layer (1) 0. 86 1. 12 1. 18 Upper Layer 1. 50 1. 90 d. 18
1 One layer.
The lower layer designation used in Table I refers to the layer containing the surface through which the needle protrudes, the upper layer containing the surface first penetrated by the needles.
Example II Example I is repeatedexcept that the batts are needled to give penetrations per square inch. The density values for the resulting batts are given in Table II.
TABLE II Denieru 4. 75 1s 2s 37 Density, lbs/cu. it;
a 0. S9 1. 75 2. 22 2. 92 Lower Layer 0.75 1. 04 1. 26 1. 46 Upper Layer 1. 10 2. 25 2. 65 0'. 336
Example Ill Example I is repeated except that the batts are needled so that 0.75 inch of the needle blade protrudes from the batt. The resulting batts have a relatively uniform density with no indication of two layers.
Polyesters suitable for the practice of this invention are those crystallizable linear condensation polymers containing in the polymer chain carbonyloxy-linking radicals,
Polymers containing oxycarbonyloxy radicals are comprehended within this group. The polymers should be of fiber-forming molecular weight. Copolyesters, terpolyesters, and the like, are intended to be comprehended within the term polyesters.
Examples of crystallizable, linear condensation polyesters include polyethylene, terephthalate, polyethylene terephthalate/isophthalate (/15), polyethylene terephthalate/hexahydroterephthalate (/10), polyethylene terephthalate/S-(sodium sulfo)isophthalate (97/3), poly- (p-hexahydroxylene terephthalate), poly(diphenylolpropane isophthalate), poly(diphenylolpropane carbonate), the polyethylene naphthalene dicarboxylates (especially those derived from the 26 and 27-isomers) and poly- (m-phenylene isophthalate), as well as many others.
The heavy denier-per-filarnent product of this invention, in addition to being highly suitable for use as a cushioning material in upholstered furniture, is also useful in the manufacture of pads to be used as domestic or industrial scouring and polishing materials. Such scouring and polishing materials are prepared by impregnating and/or coating one or both sides of the dual density webs with a water-insoluble resinous material, in the form of a latex, dispersion, or solution, with or without abrasive particles.
Since many different embodiments of the invention may be made without departing from the spirit and scope thereof, it is to be understood that the invention is not limited to the specific illustrations except to the extent defined in the following claims.
. I claim: a
1. A unitary stratified batting, suita le for use in upholstered furniture; of crystallizable, linear condensation polyester staple fibers having a denier per filament of 15 to 75, a fiber length of 2 to 6 inches, and between 2 and 15 crimps per inch of fiber; the batting having a density within the range of 1.4 to 2.9 pounds per cubic foot, the major portion of the batt thickness being a substantially uniform layer having a higher density within the range of 1.8 to 3.5 pounds per cubic foot, and the higher density layer being unitary with a substantially uniform layer having a lower density within the range of 0.9 to 1.5 pounds per cubic foot; the fibers being entangled throughout the batting and invidual fibers being oriented in a position substantially perpendicular to the face of the batting through said higher density layer and extending into the lower density layer.
2. A unitary stratified batting for upholstery use of linear condensation ethylene terephthalate polyester staple fibers having a denier per filament of 25 to 45, a fiber length of 2 to 4.5 inches, and between 4 and 10 crirnps per inch of fiber; the "ba ting having a density within the range of 1.6 to 1.8 pounds per cubic foot and consisting of two layers, a layer of substantially uniform higher density within the range of 2.8 to 3.0 pounds per cubic foot and a layer of substantially uniform lower density within the range of 1.0 to 1.2 pounds per cubic foot; the fibers being entangled throughout the batting and individual fibers being oriented in a position substantially perpendicular to the face of the batting, through said higher density layer and extending into the lower density layer, to provide a unitary structure.
References Cited by the Examiner UNITED STATES PATENTS 2,978,785 4/1961 VVenzell et al 16l154 X 3,112,552 12/1963 Smith 16l154 X 3,171,151 3/1965 Sickle et al. 161-154 X ALEXANDER WYMAN, Primary Examiner.
MORRIS SUSSMAN, Examiner.