Method of making a napped fabric

April 6, 1965

F. T. SPENCER

METHOD OF MAKING A NAPPED FABRIC Filed June 26, 1963

3,176,643

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INVENTOR.

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United States Patent Office _{Patented Α}*¹⁷_β^

3,176,643

METHOD OF MAKING A NAPPED FABRIC Francis T. Spencer, Biddeford, Maine, assignor to Pepperell Manufacturing Company, Boston, Mass., a corporation of Massachusetts

Filed June 26,1963, Ser. No. 290,676

Claims. (CI. 112—266)

This invention pertains to napped fabric, for instance blanket cloth, and more especially to napped fabric produced by the so-called “tufting method.”

In accordance with the more usual practice in the manufacture of blanket cloth or other napped materials, a fabric is first prepared by interweaving warp and filling yarns on a loom of usual type in which each pick of filling is introduced individually. Even though the filling yarns may be relatively coarse and though a high-speed loom be employed, the weaving of even one inch length of the fabric takes an appreciable time. Furthermore, in the process of napping, the nap fibers are actually torn away from the constituent yarns of the base fabric so that the more lofty the nap the weaker becomes the cloth.

To speed up production and in order to produce a lofty nap without unduly weakening the cloth, the production of such napped material, by a tufting operation, has come into use. In accordance with this procedure, a relatively thin base fabric, usually woven from spun yarns of high count and closely woven to form a firm fabric, is presented to a tufting machine having rows of tufting needles which punch loops of tufting yams (of a material appropriate to form the desired nap) down through the base fabric where they are held merely by the frictional grip of the fabric to prevent their withdrawal. Usual tufting machines work at very high speed so that after having once prepared the thin base fabric, the completion of the tufted material is very rapid. When once the tufted material has been prepared, the napping operation, which only affects fibers of the tufting yarns, may be carried out to any desired degree without weakening the base fabric. In this way, a very deep pile or nap may be produced, and the napped cloth, as a whole, is as strong as the original base fabric and capable of withstanding wear.

While this latter method of preparing blanket or similar napped cloth appears at first glance to be cheaper and better in many respects than the older method of weaving the base fabric and then napping it, it does involve the first preparation of the thin base fabric and since, as above noted, this base fabric is usually made of high count spun yarns closely woven and thus slow of production, the total cost of the completed napped cloth is approximately as great, if not greater than that of preparing and napping a woven fabric.

The usual American tufting machine applies tufts to one surface, only, of the base fabric, but certain of the British machines advance the base fabric between two oppositely arranged rows of tufting needles which apply tufts to opposite sides of the fabric simultaneously. This produces a material which may be napped so as to give a high, lofty nap on the opposite sides of the cloth.

The present invention has for its principal object the provision of a napped material useful, for example, as blanket cloth, which may have as lofty a nap on one or both surfaces as that which may be produced by the conventional tufting operation, but which may be made at a cost substantially less than that involved in the preparation of napped fabric by the usual tufting method and which, although having a very lofty nap (on both sides, if desired), has adequate strength to withstand the stresses of wear. A further object, is to provide a napped fabric suitable for use as blanket cloth, comprising an open50 mesh base fabric whose threads are of high-tenacity filamentous synthetic yarns, thus insuring high tensile strength, and which because of its open structure may be made at high speed, but with provision whereby, in spite of the open-mesh of this material, the tufting yarns are securely anchored in place. A further object is to provide a material, useful, for example, as a blanket cloth wherein a net-like fabric, woven or otherwise produced from high-tenacity filamentous synthetic yarns or equivalent material, has combined therewith a substantially continuous but air-pervious sheet of material which affords adequate anchorage for the tufting yarns, and wherein the composite base fabric, thus comprised, is soft and flexible and entirely satisfactory to form a firm anchorage for the nap-forming yarn. A further object is to provide a novel material useful, for example, as a blanket cloth and which includes a base fabric comprising an open net, woven or otherwise produced from high-tenacity filamentous synthetic yarns, and one or more plies or layers of a foamed material, for instance polyurethane foam, which is substantially continuous, flexible, light in weight and uniformly pervious to air, and of a heat-insulating character, and which affords firm and adequate anchorage. for tufting loops. A further object is to provide a novel method of making a napped fabric having a lofty nap and which has all of the requisite tensile strength, flexibility and porosity for use, for example, as a blanket cloth and whereby such a material may be produced at a lesser cost than material having generally similar characteristics which is produced by the customary tufting procedure..

Other and further objects and advantages of the invention will be pointed out in the following more detailed description and by reference to the accompanying drawings wherein:

FIG. 1 is a diagrammatic sectional view illustrating a piece of fabric having a nap layer on its opposite faces and made in accordance with one embodiment of the present invention;

FIG. 2 is a section, to much larger scale than FIG. 1, diagrammatically illustrating the structural features of the fabric of FIG. 1, but before the napping operation has been completed;

FIG. 3 is a section transversely of the warp yarns of a conventional woven blanket fabric, showing it before it has been napped;

FIG. 4 is a similar sectional view showing the fabric as having been napped on one side;

FIG. 5 is a plan view, magnified, showing a piece of plain, one-and-one woven fabric, such as is commonly, used as the base fabric in making tufted material;

FIG. 6 is a diagrammatic section, in a plane perpendicular to the warp yarns of such a fabric as that of FIG. 5, showing a single row of tufting loops as having been applied to the base fabric;

FIG. 7 is a view similar to FIG. 6, but diagrammatically showing the effect of subjecting the looped surface of the tufied fabric to a napping operation;

FIG. 8 is a diagrammatic view of the back side of a tufted fabric such as shown in FIG. 6;

FIG. 9 is a view similar to FIG. 6, but showing a base fabric like that of FIG. 5, to which tufting loops have been applied at its opposite sides;

FIG. 10 is a diagrammatic plan view illustrative of one element of an improved base fabric, in accordance with the present invention, the fabric of FIG. 10 being an openmesh woven net;

FIG. 11 is a transverse section through a piece of sheet material constituting the other element of the base fabric, according to the present invention, the sheet material thus shown, by way of example, being urethane sponge; and

3,178,643

FIG. 12 is a diagrammatic transverse section through a base fabric, in accordance with the present invention, comprising the elements shown in FIGS. 10 and 11 combined, and having tufting loops applied to one of its faces, but which have not as yet been subjected to a napping operation.

Referring to the drawings and, in particular, to FIGS. 1 and 2, the numeral 28 designates a piece of fabric napped on both sides and embodying the present invention, this fabric being shown as having a body portion comprising a textile ply 21 and a ply 22 of a synthetic sponge material, for example, but without limitation, polyurethane sponge. Layers of nap fibers 23 and 24 are shown at opposite sides of the body fabric respectively. In FIG. 2, this fabric is diagrammatically shown to larger scale, wherein the base fabric, comprising the textile layer 21 and the sponge layer 22,: are shown as having been provided with tufting yarns 24 and 2S which have been punched through from opposite sides of the base fabric to form the loops 26 and 27 at opposite faces of the body fabric. In this view the tufting yarns are shown as having been subjected to the preliminary stages of a napping operation so that fibers have been pulled off from the tufting loops at opposite faces of the fabric to form a pile layer, it being understood that, as illustrated, the napping operation has only just begun so that the pile layers have not been fully developed. In this view, for ease in illustration, the tufting loops have been shown as of substantial length as compared with the thickness of the body material.

By contrast with this procedure, FIGS. 3 and 4 illustrate the construction of the more usual blanket fabric wherein filling yarns 29 are shown as interwoven with warp yarns 28 and wherein, as shown in FIG. 4, the filling yarns have been subjected to a napping operation so as to pull out fibers from the filling yarns to form the nap layer 30.

FIGS. 5, 6, 7 and 8 illustrate the construction of the usual pile fabric made by the tufting procedure, where FIG. 6 shows the body fabric 31 as a close-woven fabric made, as usual, from high count spun yarns, for example of cotton, and where, by means of tufting needles, relatively coarse tufting yarns 32 have been punched through the body fabric from one side, forming the loops 33 at the opposite side. The body fabric in this instance may be a plain, one-and-one weave, as illustrated, to larger scale, at 31 in FIG. 5, or of any other desired weave, but close-woven so as to provide a firm anchorage for the tufting loops. As shown in FIG. 7, the loops 33 have been subjected to a napping operation so as to form a nap layer on one side, the napping operation being shown as incomplete. FIG. 8 illustrates the appearance of the back side of the usual single-face napped fabric made by tufting, as illustrated in FIGS. 5, 6 and 8.

FIG. 9 shows an early stage in the preparation of a pile fabric, similar to that of FIGS. 6, 7 and 8, except that it has tufting loops at opposite sides. Thus, the base fabric 31 may be like that of FIG. 6, but, in this instance, tufting yarns 36 and 38 have been punched through from opposite sides, providing the tufting loops 37 and 39 which will thereafter be subjected to the napping operation thus forming a fabric having nap on both faces.

In accordance with the present invention, and in the attainment of one of the above-named objects, that is to say, reduction in cost, the base fabric 40, as diagrammatically illustrated in FIG. 10, is an open-mesh fabric, for instance a plain woven net or, if desired, to provide a somewhat firmer material, a net made by leno weaving, but which, regardless of the structure, in order to provide the desired tensile strength for the completed fabric comprises, in major proportion, at least, high-tenacity filamentous synthetic yarns, for instance nylon. While this component of the base fabric may be prepared by weaving, it is contemplated that it may be made in other ways, for example by knitting or netting. The mesh of this material is sufficiently coarse so that it may be made at high speed, thus reducing the cost, not only because of the relatively small amount of material required, but also by reason of the high speed of production.

Obviously, were this material alone to be used in making a tufted fabric, the tufting yarns would not receive sufficient anchorage to prevent them from being pulled out. To overcome this difficulty, the present invention contemplates combining with this open-mesh material a ply or plies of a material providing a substantially continuous body into which the tufting yarns may be punched and which will resiliently grip the tufting yarns so as frictionally to prevent them from being pulled out. A thin sheet of non-woven material, such, for example, as a foamed plastic (for specific illustration, foamed polyurethane) has been found admirably to meet the desired requirements. Such material is very flexible and light in weight as well as pervious to air and has the further advantage of being heat-insulating. The mesh fabric 40 and the layer 43 may be secured together, prior to the tufting operation, if desired, for example by the employment of an adhesive, or they may merely be assembled one on the other and fed as a unit through the tufting machine and will thereby be adequately united by the tufting loops which pass through both plies.

While, as above suggested, polyurethane foam has been found desirable, it is contemplated that other non-woven, cheap, thin and flexible material might be employed, for example material of a paper-like character made from individual fibers and prepared in a paper-making or like machine. However, in any case, the material should be permeable to air if the completed fabric is to be employed'as a blanket or garment fabric.

When, as illustrated in FIGS. 1 and 2, the fabric is to have a layer of pile on both faces, it may be necessary, at the present time, to employ a machine of British origin, particularly designed to punch tufting yarns inward from both faces of the fabric. However, in the machines now available for introducing tufting yarns from both faces, there is no fixed support for the fabric as the tufting needles approach from opposite directions and if material like polyurethane foam were to be used in its normal state in the base fabric, difficulty would be experienced in retracting the needles from the foam layer because of the tendency of the foam layer frictionally to grip the needles and because the foam layer is very stretchy. To avoid this difficulty, in accordance with the present invention, the foam layer, prior, to performing the tufting operation, is saturated with a water-soluble medium which, when applied, imparts a certain degree of stiffness to the foam layer sufficient to permit the tufting needles to be withdrawn without dragging the foam layer with them, but which, during the subsequent treatment of the napped fabric, for example by dyeing, would be dissolved out or at least lose its stiffening character, leaving the fabric as soft and flexible as though the stiffening material had not been emploj'ed. Among materials satisfactory for the purpose, it is suggested that starch; a solution of dextrine or a polyvinyl acetate emulsion, or, for example, that known as “Wicaset S-55-E” made by Wica Chemicals Inc., Charlotte, North Carolina, would be useful.

As a specific example for the preparation of the material, in accordance with the present invention, the textile ply 40 may consist of filament nylon of a denier 70 woven in a one-and-one weave with approximately 15 ends per inch in each direction, thus providing a fabric wherein the openings constitute approximately 95% of the unit area. Likewise, the layer 43, may, for example, be of polyurethane foam of a thickness of 1 millimeter and of a weight per square yard of approximately .8 ounce, and that, before the tufting operation is performed, the layer 43 will be saturated with a solution of polyvinyl acetate, or other water-soluble stiffener. In tufting the base fabric, the yarn employed for tufting may be of cotton or other

3,176,643 selected fiber, and preferably within a range of from 2.50 to 6.0 cotton count.

However, as above noted, the textile ply 40 may be of other material than that above specifically suggested providing it be such as to insure necessary tensile strength for the completed fabric; and it may be made by other processes than by weaving; while the layer 43 may be of a foamed plastic or synthetic resin other than polyurethane, providing it be water-pervious, light in weight, flexible and possess the requisite frictional or resilient gripping action to anchor the tufting loops firmly in place.

If desired, the open-mesh textile material might be interposed between two thin plies of the non-woven material, thereby to provide additional anchorage for the tufting yarns, or alternatively, for special uses, the nonwoven ply may be interposed between two plies of very coarse textile fabric.

While certain desirable embodiments of the invention have herein been illustrated and described by way of example, it is to be understood that the invention is broadly inclusive of any and all modifications falling within the scope of the appended claims.