US3451109A - Method of making non-woven fibrous web - Google Patents

Description

June 24, 1969 J. J. KLEIN 3,451,109

METHOD OF MAKING NON-WOVEN FIBROUS WEB Filed Nov. 18, 1968 United States Patent 3,451,109 METHOD OF MAKING NON-WOVEN FIBROUS WEB Joseph J. Klein, Beverly Hills, Califi, assignor to Union Carbide Corporation, a corporation of New York Continuation-impart of application Ser. No. 712,312,

Dec. 27, 1967. This application Nov. 18, 1968, Ser.

Int. Cl. D04h 18/00 US. Cl. 2872.2 Claims ABSTRACT OF THE DISCLOSURE A non-Woven material having a divided pile-like surface is achieved by needling a portion of the fibers of the non-woven material into a sheet of flexible foam and then peeling the foam away to leave the pile-like surface.

RELATED APPLICATIONS This application is a continuation-in-part of my copending US. application Ser. No. 712,312, filed Dec. 27, 1967, now abandoned which is in turn a division of my U.S. application Ser. No. 208,345 filed July 9, 1962, now abandoned.

This invention relates to a method of making nonwoven fibrous web having a pile on at least one surface. In accordance with the method of this invention there is produced a non-woven fibrous web having a pile on at least one free surface, said pile comprising staple fibers lying normal to said surface and projecting therefrom.

In carrying out the method of this invention a nonwoven fibrous web comprising fibers of staple length, preferably a low density fibrous web, is needled to an elastomeric sheet to cause a portion of the staple fibers of said web to lie in a direction substantially normal to a surface of said web and to project from said surface into said elastomeric sheet. The elastomeric sheet is thereafter stripped from said fibrous web leaving said projecting staple fibers lying in a direction substantially normal to said surface.

The low density non-woven fibrous web is made up of staple fibers which may lie randomly or may be substantially parallel, as in a card, air laid, or water laid web. Preferably the non-woven web is a low density web of high 10ft wherein the fibers are in a helter-skelter arrangement and in a three-dimensional lie. These webs are known materials. The elastomeric layer is generally a flexible foam, although other porous elastomeric materials such as sponge elastomer, or even non-porous elastomers such as crepe rubber may also be used.

The non-woven fibrous web and the flexible foam are temporarily bonded to each other by the needling. The passage of closely spaced barbed needles through the fibrous web and into the flexible foam partially compresses the web to a higher density and causes the staple fibers which are engaged by the barbs on the needles to lie in a direction substantially normal to the surface of the non-woven fibrous web and to project therefrom into the flexible foam. The fibers may project entirely through the flexible foam or they may penetrate only part of the way through. For ease of stripping in some applications it is preferred that the penetration of staple fibers into the flexible foam shall not be through the entire thickness of said foam, but only through a portion thereof. For such partial penetration of the fibers, the needle penetration should be such that the forwardmost barb of the needle does not pass through the entire thickness of the flexible foam. For other applications, such as those where a stronger bond is desired prior to stripping, total penetra- 3,451,109 Patented June 24, 1969 tion of the fibers, even to the extent of some fibers projecting through on the other side of the foam, is preferred.

Friction between the flexible foam and the staple fibers projecting therein holds the fibers relatively tightly and causes them to maintain their projecting direction after the foam is stripped away. Thus there is obtained a nonwoven fibrous web having a pile surface.

The non-woven fibrous web having a pile surface may be used without further processing for uses such as insulating interliners in clothing. Ordinarily, however, further processing and particularly the spraying of the pile surface with a resinous material and the bonding of the fibers with adhesive which may be the same resinous material used in the pile surface spray, is desirable. The amount and nature of the resinous material sprayed is related to the use to which the web is to be put. Both thermosetting and thermoplastic resinous materials are contemplated.

One of the most important applications of the web of this invention involves its use as automotive carpeting. For such use, a relatively heavy resinous spray, or a spray of rubber or other rubbery material, of the order of about 3 to 5 ounces per square yard is used to impart the desired strength and wear resistance to the web. More or less resin or rubber material is used to meet the requirements of other applications. Other applications include use as household carpeting, filtering media and furlike materials.

The invention may be more readily understood by reference to the drawings in which FIGURE 1 is a partial perspective view of the web material of this invention; FIGURE 2 is an enlarged sectional view of the web material; FIGURE 3 is a side elevation with portions of the apparatus shown in section, illustrating the process for making the web material; and FIGURE 4 is an enlargement of a zone of FIGURE 3 where peeling takes place.

In a specific embodiment described with reference to the drawings, a batt 11 of staple fibers which crisscross each other in a random, helter-skelter, three-dimensional relationship, is passed at a rate of 10 feet per minute onto a flexible moving belt 12. The belt has a permanent woven inner layer 13 and a removable polyurethane foam outer layer 14. The polyurethane foam is /2" thick and has a density of 1 /2 lbs. per cubic foot.

Batt 11 is composed of wt. percent of 16 denier cellulose acetate 2" staple and 20 wt. percent of 15 denier 2" nylon staple. The staple fibers are crimped with about 8 crimps per inch. The batt is 54 wide.

The batt and belt pass to a conventional needling machine 16 where barbed needles 17 are passed through the batt and into the foam layer in a rapid reciprocating action. The spacing of the needles and the number of strokes per minute are adjusted to provide 300 punches per square inch in the batt. The length of stroke is adjusted either for complete or partial penetration of the foam layers. For the latter the adjustment can be such that the forwardmost barbs of the needles pass about into the foam layer and do not reach its inner surface. The belt is supported under the needling area by a perforated plate, not shown.

After passing through the needling machine the batt is reduced to about 4" thickness and is needled to foam layer 14. Each penetration of a barbed needle produces a fiber punch 18 in the batt where the staple fibers which make up the batt are aligned in a direction perpendicular to the batt and project into the foam layer. The needling fixes the staple fibers in the fibrous web relative to each other at spaced points and fixes the batt to the flexible foam layer at spaced points.

Although the batt is securely affixed to the foam layer by the friction of the foam against the perpendicular fibers 3 in the many fiber punches 18, the two may be readily separated by a peeling action which applies a separating force to only a few fiber punches at a time. Such a peeling action is provided by the change of direction of the belt as it passes over its terminal roller 19.

The perpendicular staple fibers which extend into the flexible foam layer retain their perpendicular direction after the stripping action and now extend as projections or pile 21 beyond the free surface 22 of the fibrous web.

If further processing is desired, the pile web now passes over rollers 23 and 24 to change the direction of the projections or pile from downward to upward and to facilitate the application of the resinous and/or rubber coating through spray nozzle 26. Resinous material or rubber material or a mixture of such materials, is applied through the nozzle in the amount of about 3 ounces per square yard. The resinous material is a liquid epoxy resin (Shell Epon 828) which is a reaction product of bisphenol A and epichlorohydrin having an epoxy number of about 190 grams per epoxide equivalent and a hydroxy number of about 80 grams per hydroxy equivalent. The rubber material may be natural rubber or similar synthetic rubbery material in the form of a latex.

The sprayed web material is then passed through a dryer 27 maintained at about 325350 F. The adhesive coating is dried and cured in the dryer. In the case of the liquid epoxy resin the drying is effected during a residence period of about four minutes. The finished web material, suitable for automotive floor covering, is taken up on roll 28.

The resin or rubber material, or a mixture of the same, serves to impart strength and wear resistance to the pile. It also serves to impart strength and wear resistance to the web itself since the resin and/or rubber material enters the body of the web and binds the fibers at the intersections. If greater strength is desired in the web the side of the same opposite the pile is sprayed with adhesive material to further bind the fibers at the intersections and the sprayed web is then again cured as described. The spray coating of the web and the curing thereof as described is conventional.

Although the invention has been described in detail with respect to a particular embodiment thereof, it is to be understood that numerous departures and modifications are possible within the scope thereof and according to the specific requirements of the intended use.

For example, the original non-woven fibrous batt may be made of any staple fiber which lends itself to the formation of a non-woven needled fibrous batt for a particular purpose. The staple fiber may be a natural staple such as cotton or wool, or a man-made staple such as viscose or cuproammonium rayon fibers, nylon fibers, acrylic or modacrylic fibers, polyester fibers, polyolefin fibers or polyacetal fibers. The denier of the fibers may vary considerably, a suitable range being from about 3 to about 22 denier. The staple fiber is preferably crimped, usually having between about 3 and about 15 crimps to the inch. The staple length may vary considerably from about A to about 4". Mixtures of fibers may be used in the batt and a small proportion, say up to about 15% by weight, may be shorter fibers down to and including fibers of papermaking length.

The weight of the batt may also vary depending on the intended use. A suitable range is from about 2 to about 20 ounces per square yard. The thickness of the batt after needling (excluding the pile) may vary as desired, suitably from about Vs" to about /2".

The needling rate and the spacing of the needles may be varied to produce more closely spaced fiber punches, a suitable range being from about 150 to about 350 fiber punches per square inch. The depth of the needle punch (the penetration of the forwardmost barbs) can be selected to be greater than, equal to or less than the thickness of the foam belt and is suitably between about Ms" and about /2 or more, depending on the use to which the web is to be put.

The process may also be modified in details without departing from the scope of this invention. If desired, for example, the needling may be upward with the needles penetrating the batt from below and passing into the foam layer of a belt above the batt. In such a case the pile projections from the web are upward projections and the web is sprayed conveniently without reversing its direction.

The foam layer of the belt may vary in composition, density or thickness, as required. The foam layer is removable since it loses its strength after several hours or days of needling and must be replaced.

In place of the epoxy resin disclosed above, other resinous materials, natural rubber and synthetic rubbers may be used in the spray. The resinous material may be elastomeric or non-elastomeric, thermoplastic or thermosetting, depending on the use to which the final product is to be put. The resinous material may be in the form of a solution or in the form of a latex. Both homopolymers and copolymers may be used.

Suitable resins include thermosetting materials such as epoxy resins and melamine resins; vinyl and vinylidene resins, such as polyvinyl chloride, polyvinyl acetate and polymethyl methacrylate; and synthetic elastomeric materials such as the rubbery copolymer of butadiene and acrylonitrile sold under the trademark Hycar.

For automotive carpeting, as stated above, a relatively heavy spray coating of an epoxy resin is preferred although elastomeric resins may be used if desired.

For other purposes, relatively light sprays of the order of one ounce per square yard may be preferred so that the individual fibers of the pile do not become bonded to each other. For a synthetic fur-like web, a light spray is used, followed by electrification and shearing of the pile fibers to uniform length.

When the pile fibers are not sheared, it will be found on close examination that some are looped and some are not. The unlooped fibers are believed to be formed when the needle barbs engage staple fibers near their ends or when the staple fibers are torn during needling.

The dryer temperatures and residence times are adjusted to meet the requirements of the particular resins, rubbers and concentrations thereof used.

What is claimed is:

1. A method of preparing a non-woven fibrous web having a pile which comprises driving a plurality of closely spaced needles through an open low density web made of a plurality of staple fibers and into an adjacent layer of elastomeric material and thereafter peeling said fibrous web away from said elastomeric layer.

2. A method according to claim 1 wherein the penetration of said needles is limited to avoid passing fibers through the entire thickness of said elastomeric material.

3. A method of preparing a non-woven fibrous web having a pile which comprises driving a plurality of closely spaced needles through an open low density web made of a plurality of staple fibers and into an adjacent layer of flexible foam material and thereafter peeling said fibrous web away from said elastomeric layer.

4. A method according to claim 3 wherein the penetration of said needles is limited to avoid passing fibers thrlough the entire thickness of said flexible foam mater1a 5. A method according to claim 3 wherein said flexible foam material is a foam layer on an endless belt.

6. A method according to claim 4 wherein said flexible foam material is a foam layer on an endless belt.

7. A method of preparing a non-woven fibrous web having a pile which comprises driving a plurality of closely spaced needles through an open low density web made of a plurality of staple fibers and into an adjacent layer of flexible foam material and thereafter peeling said fibrous web away from said elastomeric layer.

through the entire thickness of said flexible foam ma terial.

9. A method of preparing a non-woven web having a pile which comprises driving a plurality of closely spaced needles through a non-woven fibrous web comprising fibers of staple length and into an adjacent layer of elastomeric material and thereafter peeling said fibrous web away from said elastomeric layer.

10. A method according to claim 9 wherein the penetration of said needles is limited to avoid passing fibers through the entire thickness of said elastomeric material.

6 References Cited UNITED STATES PATENTS 2,429,486 10/ 1947 Reinhardt 2872.2 X 2,974,393 3/1961 Hollowell 2872.2 X 3,122,140 2/1964 Crowe 156-148 XR 3,199,166 8/1965 Petersik 284 LOUIS K. RIMRODT, Primary Examiner.

US. Cl. X.R.

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