US3352954A - Methods of making three dimensional contoured articles from nonwoven fabrics of fibrous materials - Google Patents

Description

Nov. 14, 1967 A. H. SMITH 9 METHODS MAKING THREE DIMENSIONAL CONTOURED ARTICLES FROM NONWOVEN FABRICS OF FIBROUS MATERIALS Filed June 7, 1965 2 Sheets-Shem l BY/MV I ATTORNEYS Nov. 14, 1967 A. H. SMITH 3,352,954 METHODS OF MAKING THREE DIMENSIONAL CONTOURED ARTICLES FROM NONWOVEN FABRICS OF FIBROUS MATERIALS Filed June 7, 1965 2 Sheets-Sheet 2 FIGB FIG.4

l .\"'VE1\"1OR. ARCHIBALD H. SMETH ATTORNEYS United States Patent M 3,352,954 METHODS OF MAKING THREE DIMENSIONAL CONTOURED ARTICLES FROM NONWOVEN FABRICS OF FIBROUS MATERIALS Archibald H. Smith, 78 De Long Ave., Dumont, NJ. 07628 Filed June 7, 1965, Ser. No. 461,957 8 Claims. (Cl. 264-90) This invention relates to methods of making three dimensional contoured articles from nonwoven fabrics of fibrous materials.

A variety of machines are now commercially available for producing continuous webs of nonwoven fabrics from stocks of raw fibers, either natural or synthetic. For example, such machines produce continuous webs of nonwoven fabrics from natural fibers or from synthetic fibers such as polyester fibers, acetate fibers, rayon fibers, glass fibers, metallic fibers and the like, or from blends of such fibers. Some machines produce continuous webs of nonwoven fabrics in which the fibers of the web are arranged in non-oriented or random directions. In other machines the fibers, or some of them, are oriented in a desired direction.

Such webs, as formed, are extremely fragile and lacking in tensile strength. In most cases, therefore, the web is sprayed or otherwise treated with a bonding agent such as a resin or rubber which bonds the individual fibers to one another to give tensile strength to the web. In other cases, in which thermoplastic fibers have been blended with non-thermoplastic fibers, the web is subjected to heat and pressure to bond the fibers to one another, with the thermoplastic fibers acting as the bonding agent. In such web forming machines an unbonded web is delivered from the machine, and the web is subjected to a subsequent bonding treatment.

Such nonwoven fabrics are used for a wide variety of purposes. For example, flat webs of nonwoven fibers are used for clothing, for linings and interlinings for clothing, for quilting and padding, for sound and heat insulation, for packing and packaging, for polishing and scouring pads, and for a multitude of other uses.

Such nonwoven fabrics are also used for the manufacture of three dimensional articles such as brassiere cups, shoulder pads for clothing, hats, shoes, slippers, shoe innersoles or liners, and the like in which the flat web material must be shaped to a desired three dimensional form.

In the case of brassiere cups, for example, in which it is desired to produce a conical or conoidal form, it is customary to cut a substantially circular piece from a flat web, and to cut a V-shaped segment from the piece with the apex of the V near the center of the piece. Then the edges of V-shaped notch are brought together and stitched to form a seam which forms and holds the piece in conical or conoidal shape. In other cases, a V-shaped fold is formed in the piece and the overlapping folds are stitched to hold the piece in conical or conoidal shape.

Such methods are not only time consuming and expensive, but frequently result in the production of articles which have objectionable characteristics. In the case of brassiere cups, for example, the seam is frequently stiffer and less flexible than the adjacent material and is sometimes puckered and uneven in thickness with resulting discomfort to the user.

It is an object of the present invention to provide methods for making three-dimensional articles directly and continuously from continuous webs of nonwoven fabrics as delivered from a web forming machine, but prior to being subjected to any bonding treatment. That is, the individual fibers of the web are unbonded so that they are free to shift relative to one another as portions of the web are shaped to the desired conformations.

Patented Nov. 14, 1967 According to the present invention such a web of unbonded fibers is fed continuously onto and draped over a continuously moving conveyor belt having a plurality of three dimensional forms of the desired contour protruding beyond the general plane of the conveyor belt. The said forms are made of foraminous material such as wire mesh screen cloth, for example, and are spaced to allow portions of the web to sag into the spaces between adjacent forms, while other portions thereof are loosely supported by said forms. Such sagging of the portions of the web between adjacent forms is induced by the Weight of the web itself, due to the fact that the unbonded condition of the fibers provides virtually no tensile strength in the web. If desired, however, the rate of movement of the said conveyor may be slightly less than the rate of feed of the web thereto in order to permit additional sag ging into the space between successive longitudinally spaced forms.

The above described sagging of the web provides an initial partial shaping of the portions of the web supported by said forms. Thereafter, as theweb advances, carried by the conveyor, suction is applied to the under side of the web through the conveyor and the foraminous forms to draw the web into close contact with the forms to complete the shaping of the web over said forms to conform to the contours thereof.

Thereafter, and while the Web is held in close contact with the forms by suction, a bonding material is applied to the Web, particularly in the areas of the forms, to give at least an initial set to the fibers, so that when the forms are removed, as hereinafter explained, the formed portions of the web will retain their shape. While it is possible, at this stage, to apply all of the bonding material required for final bonding, it is preferred to make only a partial application sutficient to enable the web to be transferred, if desired, to a second conveyor which carries the web through a curing chamber where the bonding material is set and cured.

Any of the conventional bonding agents which are commonly used for bonding nonwoven fabrics may be used. Such bonding agents include solutions, dispersions or emulsions of resins such as acrylic resins, polyvinyl acetate or polyvinyl chloride, and natural or synthetic rubber latex, for example. Specifically, for most purposes, I prefer to use a solution of polyvinyl chloride in acetone and toluol, or a water emulsion of an acrylic resin, or a rubber latex dispersion diluted with water. Such bonding agents are usually applied in the present method.

Immediately after the initial application of bonding material, the web is preferably subjected to a brief application of heat to cause some evaporation of solvent in the. case of solutions, or evaporation of solvent in the case of solutions, or evaporation of water in the case of emulsions or dispersions, in order to provide an initial set sufficient to cause the formed portions of the web to retain their form. This is of particular importance in those cases when, for convenience, the web is transferred from the forming conveyor to the second conveyor above referred to.

After this stage, i.e. at the gap between the forming conveyor and the second conveyor, it is also convenient, while the under side of the web is unsupported and exposed, to apply bonding agent to the under surface of the web. Also, at this stage, or immediately thereafter, when the web is supported on the second conveyor, or at both stages, additional bonding agent may be applied to the upper surface of the web. The total quantity of bonding agent applied may be adjusted, as desired, depending on the nature of the product, up to the point of complete saturation. For most products less than complete saturation is desirable. In addition, it is possible, at this stage to apply solid particles of surfacing materials, if desired. For example, in the case of contoured, three dimensional abrasive or polishing pads, it is possible to distribute solid particles of abrasive or polishing materials on the formed portions of the web during or after the final application of bonding agent.

Thereafter, the second conveyor carries the web through a curing chamber where it is subjected to the customary conditions of temperature, air flow, etc. as may be required to set and cure the bonding agent.

As the web emerges from the curing chamber, the formed articles may be immediately died out of the web, and the remainder of the web may be returned to the web forming machine for reprocessing.

A preferred embodiment of apparatus suitable for carrying out the method of the invention is shown in the accompanying drawings, in which FIGURE 1 is a semi-diagrammatic side elevation of the apparatus.

FIGURE 2 is a top plan view.

FIGURE 3 is an enlarged section through the forming conveyor taken on the line 3-3 of FIGURE 2.

FIGURE 4 is a section on the line 44 of FIGURE 3.

FIGURE 5 is a side elevation of a finished contoured three dimensional article.

FIGURE 6 is a plan view thereof.

FIGURE 7 is a fragmentary plan view of a modified form of forming conveyor.

As shown in the drawings, the apparatus is adapted for the manufacture of brassiere cups, although it will be understood that the method and apparatus may be used for the manufacture of other three dimensional articles merely by changing the three dimensional forms hereinafter referred to.

Referring to the drawings, the nonwoven web 1 of unbonded fibers is fed continuously by the delivery conveyor 2 of a conventional web forming machine to a forming conveyor 3 carried on and driven by rolls 4, 5. As shown, the conveyor is of the conventional slat type in which transverse slats 6 are fastened to and carried by spaced belts 7, 8. For purposes of the present invention, the said conventional conveyor is modified by attaching to selected slats thereof a plurality of three dimensional forms 9, which, as illustrated herein are of conoidal form adapted for the manufacture of brassiere cups. The said forms protrude above the general plane of the upper stretch of the conveyor and are spaced apart transversely and longitudinally of the conveyor. They are made of foraminous material such as wire mesh screen cloth, for example.

Alternatively, as shown in FIG. 7, the conveyor may consist of a sheet of foraminous material secured to the belts 7, 8 and having the protruding three dimensional forms 9 formed therein.

As the web 1 is fed onto the conveyor 2, it drapes itself over the protruding forms 9, with portions of the Web supported by said forms, and with other portions of the web sagging into the spaces between said forms. As received on the conveyor, the web is so fragile and lacking in tensile strength that it tends to sag readily into said spaces. If desired, however, such sagging may be assisted mechanically by suitable guides adapted to engage the top surface of the web and to urge it downwardly as the web advances. If desired, also, such sagging may be assisted by adjusting the rate of travel of the conveyor 2 so that it is slightly less than the rate of feed of the web to the conveyor.

As the sagging occurs, the portions of the web above said forms begin to conform to the shape of said forms, resulting in a partial shaping of those portions of the web supported by said forms. The shaping is completed by applying suction to the under side of the web through the conveyor and foraminous forms to draw the web into close contact therewith and thereby readjust the fibers of the web as the web is shaped to conform to the contours of the forms.

Thus, in the embodiment illustrated, the conveyor and web carried thereby move across one or more suction boxes 10 which apply suction to the under side of the web through the conveyor. In the embodiment illustrated, four such suction boxes are indicated, and banks of spray nozzles 11, 12 are mounted above the last two of the suction boxes. The spray nozzles spray the bonding agent onto the upper surface of the web, being located in positions to direct sprays toward the areas of the foraminous forms as they pass therebeneath. In practice, it is only necessary to use a single bank of spray nozzles, but two are provided to permit alternate use. It is occasionally desirable to remove a suction box for cleaning. By providing two banks of spray nozzles, it is possible to shut off one bank, and remove the suction box below while continuing the operation of the other bank and suction box.

The suction applied and the resulting current of air passing through the web and the foraminous forms not only shapes the web to conform to the forms, but also tends to draw the bonding agent into the web. At this stage, however, it is neither necessary or desirable to apply a heavy coating of bonding agent. Preferably, only a light coating to provide an initial bond sufficient to retain the shaped forms in the web when the web is removed from the conveyor.

Immediately following the application of bonding agent, the web is subjected to heat as by passing it beneath one or more banks of infra-red lamps 13. It is not necessary to effect a complete cure of the bonding agent at this stage, but the application of heat evaporates some of the solvent or water as the case may be, thus initiating the curing aiding in retaining the shaped forms in the web.

It is convenient, though not essential, at this stage to transfer the web from the forming conveyor to a second conveyor 14 which carries the web through the curing chamber 15.

At this stage, and before the web enters the curing chamber it is given the final applications of bonding agent. Thus, one or more banks of spray nozzles 16 are mounted above the web, and if it is desired to coat the under side of the web, one or more banks of spray nozzles 17 may be mounted below the web in the gap between the conveyors.

Thereafter, the web passes through the chamber 15 in which it is subjected to the customary conditions of temperature, air flow, etc. required for curing the particular bonding agent used.

As the web emerges from the curing chamber, it is convenient to die out the formed three dimensional articles from the web. The remaining portions of the Web may then be returned to the web forming machine for reprocessing.

It will be understood that the invention may be variously modified and embodied within the scope of the subjoined claims.

I claim as my invention:

1. The method of making three dimensional contoured articles from nonwoven fabrics of fibrous materials which comprises draping a web of such nonwoven fabric consisting of unbonded fibers onto a surface having a plurality of three dimensional contoured forms protruding beyond the general plane of the surface, said forms being of foraminous material and being spaced to allow the web to sag into the spaces between adjacent forms while being loosely supported by said forms, shaping the web to conform to the contours of said forms solely by applying suction to the under side of said web through said foraminous forms, the upper side of said web being uncovered applying a fiber bonding agent to the upper side of said web while said web continues to be held in shaped form by application of suction, and thereafter setting and curing said bonding agent.

2. The method of making three dimensional contoured articles from nonwoven fabrics of fibrous materials which comprises draping a Web of such nonwoven fabric consisting of unbonded fibers onto a surface having a plurality of three dimensional contoured forms protruding beyond the general plane of the surface, said forms being of foraminous material and being spaced to allow the Web to sag into the spaces between adjacent forms While being loosely supported by said forms, shaping the web to conform to the contours of said forms solely by applying suction to the under side of said web through said foraminous forms, the upper side of said web being uncovered applying a fiber bonding agent to the upper side of said web while said web continues to be held in shaped form by application of suction, subjecting said web to heat to effect an initial setting of the bonding agent, thereafter applying additional fiber bonding agent to said web, and thereafter setting and cur-ing said bonding agent.

3. The method of making three dimensional contoured articles from nonwoven fabrics of fibrous materials which comprises draping a web of such nonwoven fabric consisting of unbonded fibers onto a surface having a plurality of three dimensional contoured forms protruding beyond the general plane of the surface, said forms being of foraminous material and being spaced to allow the web to sag into the spaces between adjacent forms while being loosely supported by said forms, shaping the web to conform to the contours of said forms solely by applying suction to the under side of said web through said foraminous forms, the upper side of said web being uncovered applying a fiber bonding agent to the upper side of said web while said web continues to be held in shaped form by application of suction, subjecting said web to heat to effect an initial setting of the bonding agent, removing said web from said forms, thereafter applying additional fiber bonding agent to said web, and thereafter setting and curing said bonding agent.

4. The method of making three dimensional contoured articles from nonwoven fabrics of fibrous materials which comprises draping a web of such nonwoven fabric consisting of unbonded fibers onto a surface having a plurality of three dimensional contoured forms protruding beyond the general plane of the surface, said forms being of forarninous material and being spaced to allow the web to sag into the spaces between adjacent forms while being loosely supported by said forms, shaping the web to conform to the contours of said forms solely by applying suction to the under side of said web through said foraminous forms, the upper side of said web being uncovered applying a fiber bonding agent to the upper side of said web while said web continues to be held in shaped form by application of suction, removing said web from said forms, thereafter applying additional fiber bonding agent to said web, and thereafter setting and curing said bonding agent.

5. The method of making three dimensional contoured articles from nonwoven fabrics of fibrous materials, which comprises continuously feeding a web of such nonwoven fabric consisting of unbonded fibers onto a continuously moving conveyor belt having a plurality of three dimensional contoured forms protruding beyond the general plane of the conveyor belt, said forms being of foraminous material and being spaced to allow the web to sag into the spaces between adjacent forms while being loosely supported by said forms, shaping the web to conform to the contours of said forms solely by applying suction to the under side of said web through said foraminous forms, the upper side of said web being uncovered, applying a fiber bonding agent to the upper side of said web while 6 said web continues to be held in shaped form by application of suction, and thereafter setting and curing said bonding agent.

6. The method of making three dimensional contoured articles from nonwoven fabrics of fibrous materials, which comprises continuously feeding a web of such nonwoven fabric consisting of unbonded fibers onto a continuously moving conveyor belt having a plurality of three dimensional contoured forms protruding beyond the general plane of the conveyor belt, said forms being of foraminous material and being spaced to allow the web to sag into the spaces between adjacent forms while being loosely supported by said forms, shaping the web to conform to the contours of said forms solely by applying suction to the under side of said web through said foraminous forms, the upper side of said Web being uncovered, applying a fiber bonding agent to the upper side of said web while said web continues to be held in shaped form by application of suction, subjecting said web to heat to effect an initial setting of the bonding agent, removing said web from said conveyor and said forms and transferring said Web to a second continuously moving conveyor, applying additional fiber bonding agent to said web, and thereafter setting and curing said bonding agent.

7. The method of making three dimensional contoured articles from nonwoven fabrics of fibrous materials, which comprises continuously feeding a web of such nonwoven fabric consisting of unbonded fibers onto a continuously moving conveyor belt having a plurality of three dimensional contoured forms protruding beyond the general plane of the conveyor belt, said forms being of foraminous material and being spaced to allow the web to sag into the spaces between adjacent forms while being loosely supported by said forms, shaping the web to conform to the contours of said forms solely by applying suction to the under side of said web through said foraminous forms, the upper side of said web being uncovered, applying a fiber bonding agent to the upper side of said web while said web continues to be held in shaped form by application of suction, removing said web from said conveyor and said forms and transferring said web to a second continuously moving conveyor, applying additional fiber bonding agent to said web, and thereafter setting and curing said bonding agent.

-8. The method claimed in claim 5 in which the rate of movement of said conveyor is less than the rate of feed of said web thereto.

References Cited UNITED STATES PATENTS 2,893,396 7/1959 Thompson 264324 3,044,117 7/1962 Alspach et al l819 3,088,859 5/1963 Smith 264-128 3,171,151 3/1965 Sickle et al. 264-128 FOREIGN PATENTS 1,054,416 4/1959 Germany.

959,953 6/1964 Great Britain.

OTHER REFERENCES Vacuum Forming in Modern Plastics, 39(9): pp. 91, May 1961.

ROBERT F. WHITE, Primary Examiner. A. R. NOE, Assistant Examiner,

Claims (1)

1. THE METHOD OF MAKING THREE DIMENSIONAL CONTOURED ARTICLES FROM NONWOVEN FABRICS OF FIBROUS MATERIALS WHICH COMPRISES DRAPING A WEB OF SUCH NONWOVEN FABRIC CONSISTING OF UNBONDED FIBERS ONTO A SURFACE HAVING A PLURALITY OF THREE DIMENSIONAL CONTOURED FORMS PROTRUDING BEYOND THE GENERAL PLANE OF THE SURFACE, SAID FORMS BEING OF FORAMINOUS MATERIAL AND BEING SPACED TO ALLOW THE WEB TO SAG INTO THE SPACES BETWEEN ADJACENT FORMS WHILE BEING LOOSELY SUPPORTED BY SAID FORMS, SHAPING THE WEB TO CONFORM TO THE CONTOURS OF SAID FORMS SOLELY BY APPLYING SUCTION TO THE UNDER SIDE OF SAID WEB THROUGH SAID FORAMINOUS FORMS, THE UPPER SIDE OF SAID WEB BEING UNCOVERED APPLYING A FIBER BONDING AGENT TO THE UPPER SIDE OF SAID WEB WHILE SAID WEB CONTINUES TO BE HELD IN SHAPED FORM BY APPLICATION OF SUCTION, AND THEREAFTER SETTING AND CURING SAID BONDING AGENT.

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