US2459804A - Shaped felted structures - Google Patents

Description

Jan. 25, 1949. c, FRANClS, JR 2,459,804

- SHAPED FELTED STRUCTURES Filed Aug. 1, 1942 INVENTOR. Chum-5. Fawn/.5,

az'Tam Patented Jan. 25, 1 949 2,459,804 SHAPED FELTED STRUCTURES Carleton S. Francis, Jr., Chestnut Hill, Pa., assignor, by mesne assignments, to American Viscose Corporation, Wilmington, Del., a corporation of Delaware Application August 1, 1942, Serial No. 453.284

3 Claims. 1

The present invention relates in general to felted structures and in particular to a process of making shaped felted structures and to correlated improvements designed to enhance the features, characteristics and uses of the products so produced.

The present application is a continuation-inpart of my copending applications, Serial No. 300,876, filed October 23, 1939 (now Patent No. 2,459,803, January 25, 1949); Serial No. 381,292, filed March 1, 1941 (now U. S. Patent No. 2,357,392), and Serial No. 405,102, filed August 1, 1941. Application Serial No. 300,876 is a continuation-in-part of application Serial No. 157,018, filed August 2, 1937, now U. S. Patent No. 2,253,000.

In the conventional procedure of making shaped felts, such as hats, it has heretofore been necessary to use fibres having feltable characteristics. It is well known in the art that certain animal fibres are susceptible to felting operations, whereas other fibres such as cotton, rayon, jute and other smooth surfaced fibres are not susceptible to conventional felting operations. Hence, the felt manufacturers have been restricted to using at least in part fibres which can be felted, such as wool, hair, fur, mohair and the like.

In the conventional procedure of making. shaped felts, such as hats, the feitable fibres are,

in one case, blown on to a form somewhat resembling the final shape, but much larger, and thereafter shrunk by aqueous hardening and fulling operations, or in another case the fibres are carded into a web which is wrapped on a form somewhat resembling the shape desired and are thereafter shrunk by such aqueous hardening and fulling operations. In both of these procedures the wet operations of fulling and shrinking must be repeated many times before the hat body is finally brought to the desired shape for blocking. These repeated wet operations require a great deal of handling, making the process costly and cumbersome and necessitate a final drying of the hat, bodies which is a slow and expensive operation.

In the blocking of shaped felted structures, such as hats, the customary practice of the industry has been to produce a felt body having initially substantially the shape desired in the final product and thereafter stretching the felt over a form. Inorder to render the felt form substantially permanent, the trade has customarily employed a sizing agent, such as shellac, which rendered the product still and temporarily fixed the structure. Shellac tends to discolor the product and render the felt non-porous, and moreover, after a shellac-sized felt has been subjected to rain or considerable handling, the shape is not retained. It is desirablev therefore to provide a method for producing shaped felted structures of all kinds, in particular hat bodies and the like, which will be given a permanent shape without substantial reduction in the porosity and without discoloration.

It is a general object of the present invention to provide a method for the production of shaped felts having a substantially permanent shape and porous structure.

Another general object of the invention is therefore to provide a means of utilizing nonfeltable fibres in the making of shaped felt structures.

It is another object of this invention to supply an economical process for making shaped felt products by which the conventional wet operations normally required are eliminated and the number of operations substantially reduced.

It is a specific object to provide a procedure for forming a hat body in the dry state with a consequent saving in material and elimination of costly drying operations.

It is another object of the invention to provide a process for producing hat bodies in which the shape is imparted to the article simultaneously with the so-called binding of the fibres so that the shape of the structure is rendered substantially permanent.

It is a more specific object to provide a method for producing a shaped felted structure from fibres which are smooth-surfaced and/or relatively straight while eliminating the conventional operations of felting and shaping heretofore employed.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

According to the present invention, a layer is formed of thermoplastic fibres alone or a mixture of non-adhesive textile fibres and thermoplastic fibres and the layer subjected to a coalescing treatment while being shaped under pressure, whereupon the potentially adhesive fibres are rendered coalescent to bind fibres in the product and fix the shape imparted thereto by the pressing operation. 1

The present invention is particularly adapted for the production of hat bodies, which term is used herein to include both unfinished as well as finished hats, but the invention is also adapted for a wide variety of uses, such, for example, as pipe insulation, molded packing material as for the protection of glass articles, shaped gaskets for liquid seals in mechanical equipment, shaped oil and gas filters, shaped washers, shaped shoe soles and shoe uppers, shaped helmets and helmet liners, and shaped shock and sound insulators. The expression shaped as used in the following into fibres either by extrusion throughspinnerettes in the conventional manner as used in the manufacture of rayon, nylon and the like, or by melting the resinous material or dissolving it in a volatile organic material and then spraying the molten mass or solution in a' fiuid, preferably into a gaseous atmosphere in such manner as to cause description and in the appended claims is intended to include any article a surface of which extends continuously into more than one plane, or any article which has a curved surface.

Thus, the present invention enables improved shaped felts to be made from jvarious natural or synthetic fibres and filaments. Among the natural fibres which may be used are wood pulp fibres, cotton, flax, jute, kapok and silk, or they may be synthetic fibres of cellulosic composition, such as a cellulose hydrate; cellulose derivatives; natural and synthetic rubber and derivatives thereof; alginic acid; gelatine; casein; and

mineral fibres such, for example, as spun glass,

asbestos, mineral wool and the like; and fibres made of natural and synthetic resins which are not rendered tacky when the potentially adhesive resin fibres are rendered tacky by heating; also, fibres and filaments made by slitting, cutting or shredding non-fibrous films, such as waste Cellophane.

The thermoplastic fibre is composed of a synthetic resinous material capable of being formed into fibres which have an inherent tackiness upon heating to a temperature below that at which the non-felting fibres are not damaged or rendered tacky and which are non-tacky at room temperature such, for example, as a resin comprising the productof co-polymerizing two or more resins such, for example, as co-polymers of vinyl halide and vinyl acetate, co-polymers of vinyl halide and an acrylic acid derivative, co-polymers of vinyl compound and styrol compound.

I prefer to use for the thermoplastic fibres, fibres which have been formed from a copolymer of resins since such co-polymers permit one to vary widely and in any desired manner such .essential properties of the fibres .as flexibility, toughness, thermosoftening point and extruding characteristics, whereas when fibres are formed from a single resin it is diflicult, and in many cases impossible, to vary. these properties and characteristics in the desired manner.

For felts that are subjected to laundering dry cleaning, the thermoplastic fibre should be insoluble in water and inert to the detergents used for laundering and dry cleaning. The resins employed are preferably those which do not soften appreciably at temperatures reached inlaundering and blocking (as in the making of hat felts), although softening during blocking is not objectionable.

In the now preferred embodiment there is used a synthetic resin fibre comprising a co-polymer of vinyl acetate and vinyl chloride which fibres are made by suitable methods known in the art. This fibre resembles rayon and is similar thereto in many respects, but it differs therefrom since it becomes tacky when heated to a temperature of from 200 F. to 350 F. When heated, it becomes adhesive to other fibres in contact with it and adheres thereto upon cooling. It is tough and firm at ordinary temperatures, insoluble in water, and inert to the agents used in laundering and dry cleaning, and shows no substantial decrease in tensile strength on being wetted.

the resinous material to be deposited in the form of a multiplicity of fibres as described and claimed in my co-pending U. S. application, Serial No. 381,292, filed March 1, 1941 (now U. S. Patent No. 2,357,392).

The ratio of thermoplastic fibre to other fibre may also vary widely depending on the properties of the two types of fibres and may be regulated to suit the purpose for which the felt is destined, but in general a minor proportion, preferably from 5 per cent to 45 per cent, usually from 5 per cent to twenty per cent, of the synthetic resin fibre will be employed. Where a greater degree of strength or a closer bonding of the component fibres is desired, their percentage may be relatively high,

whereas in soft felts, and in papers of certain construction where it is desirable to have a comparatively small amount of bonding of the component fibres, the percentage will be relatively small; The thermoplastic fibre and the other fibre are mixed by a method suitable to the production of a particular type of felt. For example, in the making of textile felts, the-fibres may be mixed. by carding, and in the manufacture of paper felts, by beating the fibres together in a suitable liquid or by adding the thermoplastic fibres to the other fibres at any time'priorto sheeting the fibres.

Alternatively, the fibrous layer may be formed by associating the thermoplastic fibres, concurrently with their formation, withthe non-adhesive fibres as by dispersing these fibres into a fluid, preferably into a gaseous atmosphere and permitting the fibres to settle in a commingled condition in the form of a layer as described and claimed in my copending U. S. application, Serial No. 381,292, filed March 1, 1941 (now Patent No. 2,357,292).

The mixture of fibres may be felted in a predetermined shape by blowing them in or on a suitable mold, or the felt may be shaped and given a desired form. The shaping takes place in the case of paper felts, preferably by molding or shaping the wet paper sheet. In the case of textile felts, it is preferable to shape the felt layer after its initial formation and after the thermal activation of the thermoplastic fibres and while such fibres are in an adhesive condition. The predetermined shape of both paper and textile felts may be permanently set by the deactivation of the adhesive or of the adhesive fibres.

The thermoplastic fibres may be rendered tacky by heating the felt before or during shaping to an appropriate temperature; for-example, by the use of dry hot air, contact with heated surfaces, steam or hot water, with or without substantial pressure. The temperature of the heat treatment will depend on the properties of the thermoplastic fibre and must necessarily be below that at which the felt is damaged. When the felt is cooled, the thermoplastic material becomes non-tacky and tough, and adheres to the other fibres, thus providing a felt which possesses increased strength and greater tenacity between component fibres.

By suitable variation in the factors of time, temperature and pressure the thermoplastic fibres may be activated to any desired extent so aceaaoe as to cause them to fusejtack to the non-thermoplastic fibres or melt, as a result of which the felt structure is set.

The tackiness of the thermoplastic fibresmaybe modified by heating such fibres in the presence ofa suitable plasticizer depending on the particular type of fibre. The plasticizermay be incorporated in or carried by the thermoplastic fibres and/or by the non-feltable fibres and may be incorporated in the fibres at any point prior to heating. In the preferred embodiment the plasticizer is incorporated'in the thermoplastic mass prior to its formation into fibres. The plasticizer lowers the temperature at which the resin fibres are rendered tacky upon heating. After heating, the plasticizer is preferably removed by suitable means. i a

In the accompanying drawing:

Fig. 1 is a view, partly in elevation and partly in section, of an apparatus which may be employed to produce a shaped fibrous structure according to the present invention;

Fig. 2 is a sectional view, on larger scale, of-

the mold which forms a part of the apparatus of Fig. 1;

Fig. 3 is an elevational view of an alternative form of the apparatus, showing a mold member with fibrous layers or strips applied thereto; and

Fig. 4 is a view, partly in elevation and partly in section, of the complete mold employed in the alternative procedure.

For a more detailed description reference should be made to the accompanying drawing. For example, referring to Fig. 1 the potentially adhesive fibres produced by the spray gun i and the non-adhesive felt fibres introduced through pipe II by means of theblower l2 are commingled in the chamber l3 and the volatile solvent exhausted through the pipe I. The base of the chamber i3 is preferably tapered as shown and the bottom closed by a circular mold [5 provided with a multiplicity of small perforations l6 (see Fig. 2) and adapted to be evacuated through pipe ll centrally positioned in the base plate l8. The entire mold is adapted to be slowly rotated by means of pulley l9 and belt 20. When fibres are deposited on the surface of the mold the application of suction on the interior of the mold prevents the fibre from moving or sliding to the edge of the mold. When a layer 2| of fibres of suflicient thickness has been obtained on the mold, the mold is removed from the chamber and an unperforated female mold 22 of suitable configuration and size is placed over the fibrous layer 2|. as shown in Fig. 2. Upon the application of heat or organic solvents and pressure, the potentially adhesive fibres in the fibrous mass may be activated and the mass pressed into a permanent form having the shape of the mold. Heat may be supplied to the molds i5 and 22 by means of fiames, a hot water jacket (not shown), or by means of electrical heating coils 23 embedded in the molds. Obviously, by changing the size and configuration of the molds, fibrous products of various shapes may be produced in a simple and economical manner.

Referring to Figs. 3 and 4, there is shown suitable apparatus for forming a molded hat or a hat body. In this embodiment the fibrous layer containing the potentially adhesive fibres is cut into a strip 25 and this strip is wound in overlapping relation on a male hat mold 26 mounted upon a support 2'! which can be rotated by means of a shaft 28 to rotate the mold. The mat of fibres can be applied to the surface of the mold 26 in overlapping layers, as illustrated, until a body of requisite thickness is built up, There is deposited over this layer while ityis" ounted .on the mold 28 a conforming mold .29. n the now preferred embodiment the molds 28 and 29 are both hollow and have perforations on their contiguous surfaces. The shaft 28 is made hollow so that steam may be applied to the interior of the mold 26 and suction may be applied to the interior of the mold 29 through the pipe 30 so that the steam may beforced to pass through the felted layer. However, it is to be understood that the - molds 26 and 29 may be heated by any conventional means. No claim is made to the process of activating the thermoplastic fibres by means of steam in this application since this subject matter is claimed in my co-pending application, Ser. No. 453,454, filed August 3, 1942 (now U. S. Patent No. 2,430,868).

As a result of the heat-and pressure, not only are the overlapping layers of the strip 25 caused to coalesce to each other, but the thermoplastic fibres in these layers are rendered adhesive, thus binding fibres in the mass and setting both the structure and the shape of the hat body. This same procedure and apparatus may be used for molding and permanently shaping hollow-bodies of various types other than hats. Inanother embodiment of the invention a hatbody is produced-by carding on a. conventional card a mixture of fibres comprising 35% of resin fibres, preferably a co-polymer of vinyl chloride and vinyl acetate, 10% cotton fibres, and viscose rayon staple fibres. These cards are narrow and produce a web approximately 8 to 12 inches wide.

The web is taken off the card on to a doubleended conical roll, which roll revolves but at the same time is mounted on an eccentric device so that the web is wrapped diagonally around the double-ended cone in a manner similar to wrapping a bandage. In this way the web is uniformly distributed around the cone. When a sufiicient thickness of web is built up, which in a relatively uncompacted form is about an inch to two inches in thickness, the bat thus formed is cut around the maximum diameter of the double-ended cone in a manner to produce two cone-shaped bats approximately the size of the hat to be formed from them. These cone shaped bats are termed bodies.

The bodies are placed in the female die of a hydraulic press which die is designed according to the shape of the hat desired. In order to avoid the possibility of plastic fibres sticking to the die we have found it desirable to line the die with a. flexible knitted cotton fabric. The

female member of the die is heated with high pressure steam and we have found that a temperature approximating 240 degrees Fahrenheit is satisfactory. The male member of the press is made of rubber-and is expanded from the inside hydraulically. In practice it was found that preheating of the rubber male member gives us sufiicient heat by transfer to the male member to cause fusion of the hat body on the inside, as well as the outside, but there is no tendency of the plastic fibres to stick to the rubber unit.

A time element of 10 to 15 seconds with a pressure of 50 to 75 pounds per square inch suflices to give a satisfactory bond.

when hats have been produced according to the process of this invention, it will be found that the surface of the felt may be enhanced in appearance by applying short fibres so as to give the hat a suede finish. In the now preferred embodiment, to the suri'aceofthe'pressed and shaped hatthere is applied a film'oi'. asuitable adhesive, such, for example, as rubber latex, a J

resin or a cellulose derivative: in a suitable solvent and the solvent evaporated to leave the adhesive in a tacky condition. While the adhesive. is in a tacky condition, short fibres are? blown and deposited on the adhesive. In the "now preferredv embodiment the fibres deposited by -flocking under a magnetic field, so that the fibres are caused to stand on endand thus provide a shortpile which simulates suede. In

this manner, a very attractive hat may be pro-- duced in a simple and economical manner, and since thefiocking fibres may be of any color as mixture of colors, various colors and shades may be imparted to the hats so-produced.

Another method of decorating the pressed hat is to coat the surface of the hat with a thermoplastic adhesive and thereafter apply over the surface a. flexible decorated fabric. The hat carrying the fabrici's then subjected to pressure in the same hat mold used in forming-the hat. In this manner'the'tabric is'caused to permanently adhere over entire surface of the hat,

thus providing the hat with a surface which is formed of the fabric rather than ofthe felt. This improves the abrasion resistance of the hat and aifords a means of impartinga new decorative eifect. v

Iclaim: e v e 1 1. A-fibrous structure of fixed inherent shape having a non-planar configurated wail of; predetermined thickness' comprising non-cementitiou's fibres and thermoplastic resin fibres formed of a copolymer of vinyl chloride and vinyl acetate and being normally-non-tacky, flexible and tough and being renderedtacky ata temperature below that at which the non-cementitious fibres are damaged, fibres in said product being bonded together and said non-cementitious fibres and said resin fibres'being arranged in universally multi-directional' truss-forming and permeable relation to each other, the said-wall having a fixed inherent shape established by post-assembly activation and deactivation of the resin fibres throughout the areaand thickness of said-wall.

2; The fibrous structure of claim 1 wherein'the resin fibres are present in an amount'between about 5% and about 45%.

' 3. The fibrous structure oi claim 1 wherein the resin fibres are present in an amount between about 5% and about 20%. Q

CARLETON B.1"RANCIS,Ja.

REFERENCES crrnn The following references are of record in the file or this patent:

UNITED sums m'mn'rs Schneider June 8, 1943

Images