Synthetic down

Abstract

A fibrous body simulating natural bird down in its physical and functional aspects in that it is light in weight, has equivalent insulating characteristics, will not mildew or become soggy in the presence of water, has excellent laundering and dry cleaning characteristics, is lower in cost and is not dependent on the vagaries of nature which may result in periodic short supply.

Description

BACKGROUND OF THE INVENTION

Natural bird down finds its principal use as a filler for such articles as pillows, sleeping bags, clothing and the like where compressability, resiliency, lightness, breathability and cleanability are primary desiderata. However, this material is not plentiful and is therefore expensive, resulting in the use of materials which leave much to be desired, for example, Kapok, which mats readily and is therefore seriously lacking in resiliency, herein termed, for conciseness, compression-release characteristic. Other examples of materials heretofore used are Fortrel 7 and Dacron 2, which are used in a flat configuration and with which matting is a problem.

A synthetic substitute for bird down would possess all of the attributes, e.g. fluffiness, of the material as found in nature and perhaps even be superior, such as low cost.

SUMMARY OF THE INVENTION

The present invention utilizes fibers of synthetic materials, crimped or uncrimped, e.g. a polyester, which is readily obtainable as tow and may be formed into sheets, cut and fabricated into bodies of cylindrical or spherical form, as tufts or feathers, in bundle form and other forms whereby repeated compression-release cycles equivalent to those obtained with natural down may be realized to an optimum degree. For convenience, these elements are sometimes referred to as "bodies."

Although synthetic filaments are preferred in the practice of the invention, I do not intend to exclude natural fibers.

The myriad fibers in a typical body provide considerable resiliency, not only in terms of the body per se, but in terms of an assemblage of a plurality of bodies, which may be described respectively as "individual resiliency" and "collective resiliency." It has been found that the collective resiliency closely approaches the same weight or volume of natural down and the cost is substantially less. In certain preferred forms the bodies correspond substantially to figures of revolution and are preferably fabricated to possess least density in the neighborhood of the axis and greatest density at the periphery. However, substantially uniform density is within contemplation. The bodies will respond to an applied force in the manner of a spring.

Preferably, the larger bodies which are in the form of a figure of revolution will make up most of a mass of assembled bodies, e.g. as the stuffing of a pillow, while those bodies which are feathery in form will constitute the lesser proportion. The feathery bodies are relied upon to fill the voids between the larger bodies. For convenience, the larger bodies are sometimes referred to as circular bodies. From a commercial aspect the circular bodies may be pre-mixed with the feathery ones.

The bodies may be mixed together at random with full retention of the advantages described; they may be repeatedly subjected to compression and release substantially without "fatigue failure", i.e. a gradual diminution of resiliency. Regarded as discrete elements, they may be fabricated in a number of forms characterized in common in the respects pointed out above. However, one form may be manufactured at lower cost and, other factors being equal, is therefore preferred. The present disclosure is not concerned with machines for manufacturing the bodies to which the present specification is directed.

The bodies are preferably formed from tow which is separated or opened out into bundles of a variable number of fibers and cut into staple fibers of a length depending on the size and configuration of the bodies to be formed therefrom. The tow can comprise crimped or uncrimped fibers of any suitable material, preferably a thermoplastic resin, such as Fortrel 7 polyester. Mixtures of fibers of different composition and/or denier are within contemplation. Either before or after forming the same into the two principal kinds of bodies described above the bundles are sprayed with a compatible binder, e.g. dilute acrylic latex, nitrile latex or like substance capable of adhering the fibers of the unit to maintain the desired shape without adding boardiness. The binder is preferably applied in such a way as to bind the fibers at points of intersection -- not necessarily the deepest recesses of the body, but at least in a stratum adjacent the boundary of the body. In applying the spray, care should be taken to avoid closing the interstices between fibers which otherwise might detract from breathability. Desirably the binder is applied in such a way as to obtain substantially uniform distribution thereof throughout the entire extent of the body. Other methods of preserving the shape of the unit may be employed, e.g. fusion by conventionally applied heat, impulse heating, laser or ultrasonic energy. Chemicals such as propylene carbonate or ethylene carbonate, may be used.

The staple fibers may be cut from the treated tow, as described, or from picker lap, card sliver, roving or other assembled plurality of fibers.

Following treatment of the bundles of fibers with the binder, they are fed to any suitable machine which will form the same into the desired configuration, e.g. a figure of revolution. Following this step the bodies are deposited on a conveyor for movement to a drying station, e.g. an oven. Such heating, say at 410.degree. F., will also serve to set certain synthetic fibers, i.e. polyester, whereby to preclude shrinkage.

DESCRIPTION OF THE DRAWING

FIGS. 1 to 11, 13 and 14 illustrate typical configurations which the body may assume in practice.

FIG. 12 shows an intermediate stage in realizing the configuration of FIG. 13.

DESCRIPTION OF CERTAIN PREFERRED EMBODIMENTS

All of the illustrated embodiments comprise staple fibers, e.g. polyester fibers, preferably of from 1" to 3" in length. The denier and staple length are not critical except to note that the body should retain essentially the shape to which it has been initially formed. Setting of the body may be accomplished by any suitable means, e.g. application of heat.

Typical bodies within the scope of the present disclosure are shown in the drawing and will now be described.

FIG. 1 represents what may be termed a substantially sperical body which, as will be understood, is a figure of revolution. FIG. 2 shows a substantially cylindrical body, another figure of revolution. In both examples the exterior planes will, inevitably, have a hairy aspect. In the case of FIGS. 1 and 2 it has been found that improved resilient behaviour may be realized if the density of the fibers or filaments is greatest at the periphery and least at the center or central axis, as the case may be. The embodiment of FIG. 2, as well as those of FIGS. 3 and 4 are fabricated by rolling or winding a batch of staple of the required length. Initially, while in the form of bundles, and later, in the finished product, the fibers will be oriented in generally parallel array but many fibers will intersect, whereby to provide coherence and implement the resilience of the body. The bodies of FIGS. 3 and 4 result from incomplete rolling of the fibers. The stub 15 or 15a of these embodiments tends to preclude matting when the bodies are contained within a confining envelope, e.g. a pillow case.

The alternative body of FIG. 5 is formed by bending a bundle of staple fibers or filaments into U-shape and fixing the same by means of a fused or adhesive joint 17. The ends 18 will tend to assume a fanned-out aspect, substantially as shown. When a quantity of such bodies are assembled, the ends 17 will interlock with adjacent bodies. In this way an assemblage of such bodies or bodies of other shapes will exhibit synergistic behaviour. It will be apparent that what would otherwise be voids between bodies are substantially occupied by the brush-like ends 18.

Still another modification is shown in FIG. 6. In this case a bundle of staple fibers or filaments is fused or adhered transversely, as at 21, and the fibers on both sides of the joint formed to resemble the legs of a U. Bodies of this configuration will tend to interlock, the legs of one or more of these bodies entering the bight of one or more adjacent bodies whereby the resiliency of the several elements is compounded.

FIGS. 7, 8 and 9 may be considered together. Each bundle of staple fibers or filaments is joined at the center or at one end. In each case a single bundle 23a, 23b or 23c may be unilateral or bilateral. The bilateral alternative is indicated in phantom. FIG. 7 shows a generally flat tuft of fibers 24a. FIG. 8 shows a generally conical tuft of fibers 24b and FIG. 9 shows a generally pear shaped tuft of fibers 24c. In the bilateral situations, the optional tufts are indicated at 25a, 25b and 25c.

FIGS. 10 and 11 may be considered together. In the case of FIG. 10 a bundle of fibers disposed in substantially cylindrical array has one common end fanned out to provide a mushroom-like body. FIG. 11 is similar except that here there are ends extending at random from a cylindrical core of the kind shown in FIGS. 2 or 10. Such configuration may be likened to a pin cushion. The behaviour of an assembled plurality of bodies in accordance with FIGS. 10 and 11 is similar to that described in connection with the preceding figures.

Bodies in accordance with FIGS. 13 and 14 are fabricated by bringing together elongated bundles 31 and 32 which may be flat, as shown, or of other cross section (FIG. 12). One or both of these bundles is formed into serpentine form and joined as indicated at 34 in FIG. 13. In the case of thermoplastic fibers a heated blade or roller (not shown) may be pressed down or passed over the bundle to fuse the fibers. Inasmuch as the bundles are buckled longitudinally, the result is a series of arches 35 defining voids 36. This arched construction of resilient fibers provides a body (FIG. 14) which, when assembled as a plurality, yields a mass of highly resilient character.

The embodiments of FIGS. 6, 7, 8 and 9 are adapted to be mixed with bodies of the forms shown in FIGS. 1 to 5, 10, 11, 13 and 14, the dimensions of this latter group are so chosen as to substantially fill voids occurring between the bodies of the former group. However, it will be understood that a mixture of the different sizes and shapes of bodies is a matter of choice, taking into consideration the characteristics desired in the finished article, e.g. high loft and bulk in the case of a sleeping pillow and lesser bulk in the case of a sleeping bag. Ordinary staple fibers may be blown in with the formed bodies to fill the voids.

In FIGS. 1 to 5, 10 and 11, the density of the fibers is preferably least at the core and greatest as the exterior is approached, and for the reasons stated.

Those embodiments shown in FIGS. 7 to 9 may be referred to as "feather-like" since they do closely resemble natural feathers, e.g. goose down. One way in which the form of FIG. 7 may be fabricated is to begin with a more or less flat bundle of fibers and unite the same at one end 23a or at about the mid-point of the bundle to provide either a unilateral clump of fibers 24a or bilateral clumps 24a-25a respectively.

In the case of FIGS. 8 and 9 the initial bundle of fibers will be in substantially cylindrical form, giving rise to substantially conical or pear-shaped clumps 24b-25b or 24c-25c, as shown. Subsequent processing is the same as has been described in connection with FIGS. 3 to 6, 10 and 11.

From the foregoing it will have become clear that there have been provided fluffy and extremely light weight resilient bodies which may be assembled into a plurality as a filling for pillows, garments, sleeping bags and other applications wherein heat insulation, light weight, excellent compression-release characteristics, ready availability and low cost are important desiderata. Experiments have demonstrated that an assembly of the invention bodies will deform in response to load and recover to substantially the same degree as natural bird down, e.g. goose feathers, is far lower in price, is proof against deterioration, may be repeatedly laundered or dry cleaned and is hypo-allergenic. Furthermore, the invention bodies may be readily blown into the space intended to receive them, in the same manner as natural down. It is pointed out that other materials presently on the market and intended as a substitute for natural down, clog the duct through which the material is passed and guided into the receiving envelope. Kapok is blowable, but tends to mat under the rigors of use.

Although no exhaustive comparison has been made, it is believed that the rounded configuration of the bodies enables them to roll and slide on each other with much greater ease than is the case with other simulated versions as referred to above. Thus the tendency to jam in the duct is relieved.

Claims

I claim:

1. An assemblage of man-made bodies each functioning in simulation of bird down as found in nature, each said body comprising a myriad of fibers formed into a rounded configuration which is capable of being repeatedly deformed in the manner of a spring by application of a load and recovery substantially to its original form upon release of the load.

2. The combination in accordance with claim 1 further characterized in that some substantial proportion of the fibers are bonded together over some predetermined length thereof.

3. The combination in accordance with claim 2 wherein the bond is constituted by a hardenable liquid binder material.

4. The combination in accordance with claim 2 wherein the bond is a fused joint.

5. The combination in accordance with claim 1 in which the rounded configuration of the body is a figure of revolution.

6. The combination in accordance with claim 1 in which the rounded configuration is substantially spherical.

7. The combination in accordance with claim 1 in which the rounded configuration is substantially cylindrical.

8. The combination in accordance with claim 1 in which the body has a greater density of fibers at the exterior gradually diminishing to a least density as the center of the body is approached.

9. A man-made body functioning in simulation of bird down as found in nature, said body comprising a relatively open, rounded, fibrous mass of low average density comprising self-sustaining, non-woven fibers bonded together, said mass being characterized by rapid recovery following deformation under load.