US2357392A - Process for producing fibrous products - Google Patents

Description

- p 1944- c. s. FRANCIS, JR 2,357,392

PROCESS FOR PRODUCING FIBROUS PRODUCTS Filed March 1, 1941 INVENTOR fRLZ-TO/V FRANCIS J 1 dered adhesive to bind the fibres together.

Patented Sept. 5, 1944 PROCESS FOR rnonuomc. FIBROUS rnonuc'rs Carleton S. Francis, Jr., Pine Orchard, Conn, as-

signor to Sylvania Industrial Corporation, Fredcricksburg, Va., a corporation of Virginia Application March 1, 1941, Serial No.381,292

20 Claims.

The present invention relates, in general, to a process for producing textiles, felts and felted structures including paper, and more particularly such fibrous products formed at least of two types of fibres, one of which can be ren- The invention also relates to correlated improvements designed to enhance the quality, utility, structure and properties of such products without detrimentally affecting the flexibility, porosity or other desirable characteristics inherent in the products.

In my co-pending United States application Serial No. 157,018 filed August 2, 1937, I have disclosed and claimed textiles, and. in my copending United States application-Serial No. 300,876 filed October 23, 1939, I have disclosed and claimed felts and paper, all of which fibrous products are formed from at least two types of fibres, one of which can be rendered adhesive by heat to bind the fibres together. Thermoplastic fibres heretofore manufactured and sold are formed by extrusion through spinnerettes such as are used in the manufacture of rayon. Such extrusion processes are limited to the use of certain plastic compositions having proper filtering characteristics, requisite solubility, viscosity, wet and dry tensile strength and other characteristics necessary for spinning the ma-- lengths within a narrow range imposed by their use on conventional textile and felting equipment, that is, the cut staple fibres must be capable of being carded, drafted, spun and felted on standard equipment used for making textiles and felts. Moreover, it is not practical, in many cases, to incorporate plasticizers, hardening agents and the l ke in th plastic composition before extrusion since such additions change the spinning properties and the products so produced can seldom be sold as regular textile fibres, but must be limited to special uses as in the inventions of my copending applications, thus decreasing the market and increasing the cost of such. specially formulated fibres. Accordingly. the combination of the above-mentioned factors limits the artific al fibres available to a-few kinds of thermoplastic materials, to a narrow range of fibre lengths and deniers, to certain kinds of plasticizers and puts the thermoplastic fibres so produced in a high price range.

. Therefore, it is a general object of the present invention to provide a process of making in a I simple and economical manner fibrous products in which some of the fibres are boundtogether as a result of the activation of the potential adhesiveness of other fibres in the product. v

It is a further object of the invention to provide a process for making improved fibrous prodnets of the type just mentioned without limitation as to the nature of the material from which the potentially adhesive fibres can be made, or of the plasticizers which may be incorporated in such fibres.

It is a further object of the invention to provide a process for making the fibrousproducts of the type described without limitation as to length or denier of the potentially adhesive fibres.

It is a specific object of the invention to provide a simple and economical method of forming and commingling fibres in the formation of fibrous products of all kinds.

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

According to the present invention, fibrous Products are made by dispersing into a fluid, a potentially adhesive fibre-forming material to form fibres, associating the potentially adhesive fibres concurrently with their formation with another type offibre, fabricating said mixture of fibres into a fibrous structure, such as a textile, or felted structure, and thereafter activating the potentially adhesivefibres to bind fibres in the product. In contrast to prior extrusion methods, the potentially adhesive material in this invention is formed into fibres by dispersing it, as by spraying a plastic or molten mass of the material or a solution of the material in a suitable solvent into a fluid, preferably a gaseous atmosphere, under such conditions that a multiplicity of filamentary structures are produced as described in detail hereinafter.

In the following specification and in the claims, the term fibre" or fibres when used in reference to the potentially adhesive material is intended to include any fibril and discontinuous fibres, whether independent from one another or adhered at spaced points to form a felted product or reticulated structure. The expression felted fibrous product includes any heterogeneous mixture of at least two types of discontinuous fibres with or withoutstructure and the term fibrous structure include felt products such as textile felts and paper as well as rovings, yarns, threads and cords formed by carding, drafting, spinning, or twisting said felted mixture of fibres.

The term "adhesive includes sticky, cementitious, agglutinous, or tacky conditions. The term non-adhesive fibres includes those fibres which, although they may be rendered adhesive by some treatment, are not rendered adhesive under the conditions used to activate the potentially adhesive fibres associated therewith.

The invention is adapt d f ma f lt d' yarn, single or plied, threads and cords of all kinds which may be used as warp or as filler (weft) in making fabrics. 'or in association with other yarns of like or unlike character, in weaving, knitting, netting, lacing and other textile constructions, and when doubled or twisted with other yarns, for the preparation of threads and cords of all kinds.

The invention accordingly comprises the several steps and relation of one or more of such steps with respect to each of the others, which are exemplified in the following detailed disclosure. and the scope of the invention will be indicated in the claims.

For a more complete understanding of the invention reference should be had to the accompanying drawings, in which:

Fig. 1 is a side elevation, partly in section, of one embodiment of suitable means for forming the potentially adhesive fibres of the invention;

Fig. 2 is a side elevation, partly in section. of one embodiment of means for carrying out the invention in the fabrication of fiat felts and papers;

Fig. 3 is a side elevation, partly in section of one embodiment of suitable means for carrying out the invention in the fabrication of molded, felted structures, such as hat felts;

Fig. 4 is a section of means for activating and compacting the felted structure produced in the apparatus shown in Fig. 3;

Fig. 5 is a side view, partly in section. of suitable means for commingling fibres in the fabrieating of a textile according to the invention.

Among the non-adhesive fibres which may be employed are natural fibres such for example.

as wood fibres, cotton, flax, jute, kapok. wool, hair and silk: and synthetic fibres, such for example as cellulosin fibres, such as cellulose hydrate. cel ulose derivatives. as cellulose esters. mixed cellulose esters, cellulose ethers, mixed cellulose ester-ethers. mixed cellulose ethers, cellulose hydroxy-alkyl ethers, cellulose carboxyalkyl ethers. cellulose ether-xa-nthates, cellulose xantho-fatty acids, celulose thiourethanes; natural and synthetic rubber and derivatives thereof; fibres made of alginic acid, gelatine, casein; and mineral fibres such, for example. as spun glass, asbestos, mineral wool and the like; and fibresmade of natural and synthetic resins which are not rendered tacky when the potentially adhesive resin fibres are rendered tacky; also fibres and filaments made by slitting, cutting or shredding non-fibrous films. such as waste Cellophane.

For producing the potentially adhesive fibres there may be employed any potentially adhesive fibre-forming substance in a fiowable condition, i. e. in a plastic or molten state or solution, such for example as a cellulose derivative, a resin or rubber. Among the cellulose derivatives which are suitable are, for example, cellulose esters, cellulose ethers, mixed cellulose ester-ethers, mixed cellulose esters, mixed cellulose ethers, and mixtures of cellulose derivatives. Among the resins which may be employed for forming the potentially adhesive fibres are, for example, cheap natural resins such as shellac, dammar, copal and the like, and synthetic resins formed by the polymerization of various organic compounds such as coumarone, indene hydrocarbons, vinyl, styrene, sterol aldehyde, furlural, ketones, urea, thiourea, phenol-aldehyde resins, either alone or modified with oils, urea-aldehyde resins, sulfonamide-aldehyde resins, polyhydric alcohol-polybasic acid resins, drying oil-modified alkyd resins, resins formed from acrylic acid, its homologues and their derivatives, sulfur-olefine resins, resins formed from dicarboxylic acids and diamines' (nylon type); synthetic rubber and rubber substitutes, herein called resins, such for example as polymerized butadiene, olefine polysulfides, isobutylene polymers, chloroprene polymers; and fibres formed from a resin comprising the product of copolymerizing two Or more resins, such, for example, as copolymers of vinyl halide and vinyl acetate, copolymers of vinyl halide and an acrylic acid derivative, copolymers oi. vinyl compound and styrol compound; and also a mixture of resins, such for example as a mixture of vinyl resins and acrylic acid resins or methacrylic acid resins, a mixture of polyolefine resins and phenol-aldehyde resins, or a mixture of two or more resins from the different classes just named. There may be employed also fibres made from rubber latex, crepe rubber, gutta percha, balata. and the like.

Further, the potentially adhesive fibres may be formed from mixtures of the cellulose derivatives with resins or rubber, such for example as a mixture of cellulose nitrate and an acrylic acid resin, or a mixture of benzvl cellulose and a vinyl resin. or a mixture oi ethyl cellulose and shellac. The invention is particularly well adapted for forming the potentially adhesive fibres from compositions of cellulose derivatives, resins. rubbers. and their mixtures, which compositions are not adapted for forming fibres by extrusion through artificial silk spinnerettes, since such factors as filtering characteristics, solution viscosity and fibre tenacity are not critical in the present fibreforming process.

In making up the fibre-forming solution, the fibre-forming material may be dissolved in a suitable organic solvent which will volatilize rapidly at moderately elevated temperatures. Suitable solvent mixtures may be selected by those skilled in the art having regard for the nature of the fibre-forming substance.

As an alternative to dissolving the substance 'in a suitable solvent. the fibre-forming material may be heated until plastic or molten and the plastic or molten mass dispersed into fibres as he einafter described.

The proportion of the fibre-forming substance to the solvent will depend, inter alia, upon the nature of the fibre-forming material, the type of dispersing device employed and the type of fibres desired to be produced. In general solution concentrations of from 5% to 50% will be suitable for most fibre-forming substances and conditions.

To the fibre-forming material or solution thereof, there may be added suitable plasticizers, hardening agents for the resins, latent activatmaintain the material flowable to the point of ing agents, dyes, pigments, moth-proofing agents, fireproofing agents, water-proofing agents, and the like. In particular, it may be desirable to add to the material or solution suitable substances for lowering the thermal softening point of the fibres produced, such, for'example, as plasticizers, soft resins, and the like. Among suitable plasticizers for this purp are utyl tartrate, ethyl phthallyl ethyl glycolate, while suitable soft resins are polyvinyl acetate, ester gum, coumaron resin and the lower polymer of alkyd resins.

Generally speaking, the fibre-forming process of the invention comprises dispersing the fibreforming material while in flowable condition, that is, in solution or plastic or molten condition, into a fluid, e. g. a liquid or a gaseous atmosphere under suflicient pressure to form a multiplicity of fibres. When a solution is employed, the di persion is preferably into a gaseous atmospheze which is heated sufllciently to evaporate the solvent rapidly. In this embodiment, the organic solvent may be wasted r recovered in a suitable manner as by scrubbing or absorption. When a molten mass is dispersed, the atmosphere is preferably cooled so as to cause a rapid congealing or solidification of the fibre-forming material.

To carry out the fibre-forming process there may be used any suitable means for converting the fiowable substance or composition into fibrous form and the invention is not to be limited to the particular means hereinafter described.

In the now preferred embodiment of the invention, the fibre-forming composition is dispersed into a heated gaseous atmosphere by means of a spray gun or atomizer comprising, in combination, means to supply the fluid composition under pressure to an orifice, means to supply one or more streams of air or gas at a point adjacent the fluid orifice so as to disperse and disrupt the stream of fluid issuing from the orifice.

There is shown in Fig, 1a conventional type of spray gun, hereinafter designated generally by the reference character I, and comprising essentially a container 2 adapted to hold the fibreforming composition from which it is forced by air pressure through the supply line 3 to the chamber 4 from which the composition is discharged through the orifice 5. The air is supplied through the line 5 to the air chamber 1 which surrounds the chamber 5 and terminates in a plurality of orifices 8 positioned adjacent the orifice 5. The trigger or handle 9 isadapted to operate the pin valve III which opens the orifice 5 and the air valve II which opens the air line 5. As the stream of fibre-forming composition is discharged from the orifice 5, it is disrupted by the force of the tangential streams of 'air discharged through the orifices 8. The size, shape and character of fibre produced by this spraying operation is a function, inter alia, of the viscosity of the solution, the pressure under which the solution and air are discharged, the angle with which the air streams contact the fluid stream, but these factors and their control are well known to those sln'lled in the art and can be adjusted to produce various types of fibres without transcending the scope of the invention. Whenthe fibre-forming material is plastic or molten, the material suitably heated to render it fiowable is caused to flow into contact with an air stream whichdisperses the material into fibres, or is forced under pressure through an orifice into fibres and means may be provided to dispersion.

In another embodiment, the non-adhesive fibres or the potentially adhesive fibres may be formed by electrical dispersion in a gaseous atmosphere. For example, a stream of the fibre-forming material is caused to flow into an electrically charged field, whereupon the stream is dispersed into a multiplicity of fibres which are attracted in the at the points of mixing and depositing. Accordingly, it is possible in the present inventionto form, mix and substantially adhere or combine the fibres together in immediate sequence, that is, concurrently and continuously, merely by regulating the rate of evaporation of the organic solvent and the time elapsing between the formation of the potentially adhesive fibres and the point of contact with the other fibres.

If desired the formation of the potentially adhesive fibres may be carried out in a chamber separate from but connected with the chamber in which these fibres are associated, as by mixing, with the non-adhesive fibres. Thus a single fibre forming means may serve to supply fibres for a plurality of different mixing chambers. However, the expression concurrently with their formation as used herein includes forming and associating in immediate sequence without permitting the potentially adhesive fibres to settle before association.

The above-described fibre-forming processes may be employed for producing the non-adhesive textile or felt fibres as well as the potentially adhesive fibres. The expressions nonadhesive and potentially adhesive as used in the specification and claims are relative terms which depend upon the particular activating treatment selected; as used in Example VIII hereof, the term non-adhesive designates that fibre type which remains non-adhesive under the treatment which renders the other type adhesive.

The ratio of potentially adhesive fibre to other fibre may be varied over a wide range depending on the purpose for which the fibrous product is intended. In general, to preserve the inherent flexibility, porosity and texture of the product, a minor proport on of the potentially adhesive fibres is employed and preferably from 3%. to 20% by weight. In the production of certain products, for example, felts and textiles having reduced porosity or impermeability if desired, the

potentially adhesive fibre present may constitute a major proportion, for example, up to 65% of the total fibres.

Referring to Fig. 2, fibre m xtures suitable for the manufacture of fiat felts and paper may be produced by dispersing a fibre-forming composition by means of the spray gun I into a heated gaseous atmosphere contained in the chamber 20 into which is simultaneously blown non-adhesive felt or paper making fibres 2| through conduit 22 by means of a blower 23. The mixture of fibres falls downwardly in the chamber and comes to rest on the surface of an endless belt 24 made of flexible material such as textile, metal, leather or the like, which is positioned in a horizontal plane at the base of the chamber 20. The hat of mixed fibres is carried on the belt from the chamher and through pinch rolls 25 and 26 which compress the bat and enable it to be removed from the belt for activating or finishing operations to be hereinafter described. If the potentially adhesive fibres produced by spraying are thermoplastic, the rolls 25 and 28 may be heated sufllciently to activate the thermoplastic fibres, the fibres becoming deactivated when the felt passes from the rolls and becomes cool. The solvent evaporated from the fibre-forming composition may be withdrawn from the chamber through exhaust pipe 21 and wasted or recovered in a known manner. When using potentially adhesive fibres which are activatable by means of an organic solvent, such solvent can be sprayed on the fibre bat as it is carried on the belt, as at point A, so that the fibres are in an adhesive condition when passing through the pressure rolls 25 and 26. In the manufacture of paper felts the belt 24 may be considered as comprising the wire screen of the paper making machine. Thus, the fibre forming, mixing and felting steps in making the felts and papers are carried out concurrently and continuously, in immediate sequence, that is, in a simple and economical manner.

In the manufacture of hat felts or molded fibrous products the fibre forming and mixing operations can be similar to those just described. For example, referring to Fig. 3 the potentially adhesive fibres produced by the spray gun and the non-adhesive felt fibres introduced by the blower 23a are commingled in the chamber 20a and the volatile solvent exhausted through the pipe 21a. The base of the chamber 20a is preferably tapered as shown and the bottom closed by a circular mold 28 provided with a multiplicity of small perforations 29 (see Fig. 4) and adapted to be evacuated through pipe 29a centrally positioned in the base plate 30. The entire mold is adapted to be slowly rotated by means of pulley 3| and belt 32. 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 of fibres of sufllcient thickness has been the chamber and an unperforated female mold 33 of suitable configuration and size is placed over the fibrous layer 43. 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 28 and 33 by means of flames, a hotwater jacket (not shown), or by means of electrical heating coils 34 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.

In the apparatus shown in Figs. 2 and 3, the non-adhesive fibres may be produced from a solut'on of, or a plastic or molten fibre-forming material by use of a second spray gun positioned in the chamber 20 (20a) in place of the conduit 22 (22a). In this manner, novel felt and paper products are capable of being produced entirely of a mixture of dispersed artificial fibres, one type of which is potentially adhesive and the other is non-adhesive.

' As an alternative to the process illustrated in obtained on the mold, the mold is removed from Fig. 2, the fibre-forming material may be dis- 76 tinuously fabricated into a fibrous structure in a known manner but including the novel steps of this invention.

In this manner, the potentially adhesive fibres may be dispersed in an aqueous suspension of paper-making fibres as in the head box of a Fourdrinier or "cylinder paper machine from which box the suspension of fibres is delivered to the forming-wire of the paper machine.

In the manufacture of textiles, the forming and mixing of the potentially adhesive fibres with the textile fibres can be effected at any point prior to the completion of the spinning of the yarn, but in the preferred embodiment, the forming and mixing of the fibres takes place during or immediately after carding of the textile fibres. Referring to Fig. 5, the roll 35 represents the last or delivery roll on a conventional cotton carding machine, from which the doffer blade 36 strips the thin layer of fibres to form continuously the gauze-like web 31 of cotton fibres. There is built around the last roll35 and the web 31- a fibreforming and mixing chamber 201), the web 31 being positioned adjacent the base of the chamber and a spray gun lb being positioned at the top of the chamber. The fibres formed by the spray gun fall downward in the chamber 20b, being aided by a down draft created by the withdrawal of the solvent through the pipe 38 in the base of the chamber. The potentially adhesive fibres are thus deposited on the thin web 31 of cotton fibres and are gathered between the folds of this web as it passes out of the chamber and through the usual funnel 39 and is delivered by the rolls 40 into the sliver can 4|. During the subsequent drafting, and spinning of the card sliver 42, the potentially adhesive fibres become sufilciently admixed with' the textile fibres to achieve the objects of the invention when the textile i simultaneously activated, compacted and otherwise finished. The fact that the potentially adhesive fibres may not be of the same length and diameter as the textile fibres is not detrimental in subsequent textile processing operations. Moreover, since the potentially adhesive material is actually in fibrous form it does not sift out of the sliver or roving during drafting,-spinning, doubling, weaving or other textile operation prior to activation. As in the making of felt and paper products, the forming of the potentially adhesive fibres is effected concurrently and continuously with the mixing of such fibres with the textile fibres.

Apparatus similar to that shown in Fig. 5 may be employed in the manufacture of felts, in which case the web after having had the potentially adhesive fibre deposited thereon is not drawn into the funnel 39 but is withdrawn in web form and a bat formed therefrom in a desired manner.

The invention contemplates activating the potentially adhesive fibres and the activation may be in predetermined areas or uniformly throughout the product depending upon the effect desired; also, the textile may be subjected to two Non-adhesive fibres may be pres-,

or more activating treatments either in sequence or separated by other treatments and textile operations. Among the methods which may be used for activation are the following, taken singly or together in appropriate combinations.

1. When the potentially adhesive fibres are thermoplastic, they may be activated by heat.

2. By applying to the fibrous mixture a solvent or swelling agent or mixtures thereof with diluents, under such conditions of concentration and temperature so as to render the potentially adhesive fibres tacky. For example, fibres of organic cellulose derivatives, such as cellulose esters may be rendered adhesive by solvents, such as acetone, ethyl acetate, butyl acetate and the like.

3. When the fibres are tacky at the time of activation, they can be activated by pressure alone,

4. A latent activating agent may be combined with the potentially adhesive fibres and/or with the non-adhesive fibres. Such agent may be rendered active by a subsequent treatment, such as chemical agents, heat or irradiation, thus producing a simultaneous activation of the potentially adhesive fibres. For example, fibres may be impregnated with a liquid which, at room tem-' perature, is a non-solvent therefor but which, at a higher or lower temperature is a solvent sufiiciently active to render the potentially adresins, or by cooling; and if activation is by means of a solvent, deactivation may involve extraction of the solvent as by washing, evaporation, decomposition; if activation has been accomplished by pressing, deactivation follows upon release ofthe pressure. The removal of the activating agent depends upon whether its presence in the product is desirable or objectionable.

The activating, compacting and deactivating treatments herein described may be carried out independently of or simultaneously with, various treatments common to the fabrication, finishing and sizing of textile fabrics and materials.

Further, the products of the invention may at any time be emboss calende'red, moulded or otherwise shaped, in hole or in part, to deform the surface while the adhesive fibres are still tacky and then subsequently deactivated to set them with a desired form or surface condition to'produce effects such as grain, lustre, smoothness or designs, by suitable means, used hot or cold and with or without the aid of agents which soften, swell, plasticise the material acted on.

The fibrous products may be coloured before, during or after activation, compaction and/or deactivation, by dyeing, printing, for example, with inks containing pigments or dyestufis which are resistant to such treatments. If desired, the activating agent or the deactivating agent may be added to the dyebath or the printing ink.

The properties of the finished product depend upon various factors, such as the nature and allowedto remain in the product or it may be removed by suitable means such as washing and extraction thus again elevating the thermal softening point of the thermoplastic material and preventing reactivation upon ironing.

While the fibres are in an adhesive condition, the fibres are preferably subjected to a compacting treatment to promote adhesion of the associated fibres at their points of contact and the term compacting includes pressing, squeezing and tension. For example, mechanically applied pressure may be exerted on the activated mate--. rial during and/or after activation, and/or during calendering, embossing, printing, drying and other operations involving the use of rollers. Compacting may be accomplished by twisting or stretching the yarns, threads, or cords with or 'without application of additional external pressure. For example, an activated yarn may be wound under tension upon a spool or core. A fabric may be passed between pressure rolls to compress the mixed fibres or may be subjected to tension in one or both dimensions.

After activation, the fibrous material is treated to deactivate the adhesive, that is, to render the adhesive non-tacky so as to fix the new relationship of the fibres. The nature and extent of the deactivation treatment will depend, inter alia, upon the nature and extent of the activating treatment and upon the proportion and kind of potentially adhesive fibres used. If activation has been accomplished by heat, deactivation may be accomplished by heating to a higher temperature as with thermo-setting proportion of potentially adhesive fibres; the extent of the activation thereof; and the adhesive condition of the fibres during compacting; and the nature of the deactivation. The extent of activation, compacting and deactivation may be varied considerably, depending upon the relative proportions of the types of fibres, the properties of the potentially adhesive fibre and the effect desired in the product. The potentially adhesive fibres. may be rendered superficially tacky; or made adhesive without losing their fibrous form; or rendered sufiiciently fluid to spread under pressure to form a film in which the other fibres are embedded. If the potentially adhesive fibres are rendered only slightly tacky, the frictional resistance between fibres will be increased and the strength improved. If the potentially adhesive fibres are rendered substantially adhesive, they will cohere to each other and adhere to the other fibres to fix the position thereof to give a product having increased tensile strength and lower stretch and shrinkage, and if a film is formed the product may be given a glassy smooth surface.

By way of illustrating but not by way of limiting-the invention there will be given the following specific examples:

Example I To manufacture a textile yarn or a thread by the present process, staple rayon fibres are carded, using the apparatu shown in Fig. 5. There is produced potentially adhesive fibresby spraying through the spray gun lb a solution of 40 parts of vinyl acetate in 60 parts of acetone under a pressure of 40 pounds per square inch, the spray being so regulated that the proportion of the fibres in the sliver will be about per cent rayon and 15 per cent vinyl acetate fibres, the sliver thus produced is drafted and spun and then twisted into a. yarn in a known manner. After the twisting, the yarn is preheated to a temperature of about 250 F. sumciently long to render the vinyl acetate fibres adhesive and while they are in such an adhesive condition the yarn is passed through a heated metal eye to compress the fibres while simultaneously the yarn is placed under tension to bring the fibres into more intimate contact with each other, whereupon the tacky vinyl acetate fibres adhere to the other fibres at their points of crossing. Upon cooling to deactivate the product will be found to have a higher tensile strength, a decreased tendency to untwist, a decreased shrinkage upon washing and less nap than a yarn made in the same manner but composed entirely of rayon staple fibre.

Example II The yarn produced according to Example I is,

asaasoz siie strength and burst resistance and may be prlor to activation, woven into a textile fabric and the fabric is then passed between pressure rolls heated to 250 F. or heated to this temperature while under tension to activate the vinyl acetate fibres. The fabric shows an improved tensile strength, both wet and dry, a decreased shrinkage and a decreased slippage of the yarns one upon the other.

Example III In the manufacture of a fiat textile felt there may beused an apparatus shown in Fig. 2 in which cotton fibres are blown in simultaneously with the spraying through the spray gun ill a solution comprising 30 parts cellulose acetate, 3 parts triphenyl phosphate, 30 parts acetone and 37 parts ethyl acetate. The conditions are so adjusted that the solvent is not completely eliminated by the time the fibres are mixed together and deposited on the belt 24'. The proportion by weight of cellulose acetate fibres to cotton fibres should be about 10 to 100. The layer of fibres is then carried on the belt through the rollers 25 and 26 which are maintained at a temperature of 285 F. whereupon the cellulose acetate fibres in the felt are rendered adhesive and bind the other fibres. If necessary the felt so produced may be subjected to a drying action in a heated chamber to eliminate the residual solvent. The felt will show substantial resistance to abrasion, a relatively strong binding of the fibres' and a sufiicient compactness for the product to be useful as a shoe interlining.

Example IV there is blown into the chamber a by means of a blower 23a a multiplicity of short wool fibres and simultaneously there is sprayed through the gun Illa a solution comprising 25 parts of copolymer of vinyl acetate and vinyl chloride and 10 parts of methylmethacrylate dissolved in a mixture of 50 parts of acetone and 15 parts of chlorinated hydrocarbon, the amounts of the fibres produced by spraying being such thatthe felt formed contains 5% by weight of the resin fibres. The perforated mold carrying the layer of mixed fibres is removed from the chamber Illa and the felt subjected to heat and pressure by means of the mold shown in Fig. 4, a temperature of about 300 F. and a pressure of 100 pounds to the square inch being employed. The felt is then allowed to cool whereupon it will be found that the fibres in the felt are joined together at the points of contact with the resin fibres. The product shows a relatively high tenmay be shaped, blocked, coated, dyed, or otherwise finished as desired.

Example V The process of Example IV is carried out but substituting, for the solution therein used, a solution of 25 parts of polymerized isobutylene (Vistanex") dissolved in 75 parts by weight of toluene, and the inherently tacky fibres so produced are activated by pressure alone.

Example VI The process of Example IV is carried out by substituting for the solution used therein, a rubber latex composition containin a rubber accelerator which causes vulcanizati n at room temperature, and the rubber fibres 59 produced may be activated in the product by pressure alone. Upon standing, the rubber fibres are gradually vulcanized so that they become non-tacky and incapable of further activation.

Example VII The process of Example IV is carried out but the conduit 22a through which the natural fibres are introduced, is replaced by a second spray gun through which a solution of 40 parts of cellulose acetate dissolved in 60 parts of acetone is dispersed to produce the non-adhesive fibres, and through the spray gun la a solution of 40 parts of polyvinyl acetate in 60 parts of acetone is dispersed to form potentially adhesive fibres, the rate of dispersion of the two solutions being so correlated that the fibrous mixture produced comprises 10% of the polyvinyl acetate fibres and of the non-adhesive cellulose acetate fibres. Upon subjecting the fibre mixture to a temperature of 225 F., only the vinyl acetate fibres are rendered adhesive and the cellulose acetate fibres remain unactivated.

Example VIII The process of Example VII is repeated but the fibre mixture is treated with carbon tetrachloride which activates the polyvinyl acetate; fibres only and pressure without heat is then applied. Upon evaporation of the carbon tetrachloride the adhesive fibres are deactivated.

It is apparent that the present invention has many advantages over prior processes. For instance, by forming the potentially adhesive fibres concurrently with the mixing the steps of prespinning and carding such fibres are eliminated with all their attendant difficulties. As the spraying process is capable of producing fibres of smaller diameter than those obtainable by use of rayon spinnerettes more points of contact are produced upon the activation than are produced from an equal weight of potentially adhesive fibres formed with such spinnerettes. Thus a greater efiect is obtainable with an equal weight of fibres or the same eflect can be obtained with a lesser weight of potentially adhesive fibres. The present invention enables one to employ cheaper fibreforming materials and also materials not physically adapted for forming filaments by rayon spinning method and permits the incorporation in the fibre-forming composition of a wider variety of additional ingredients, in particular a wider variety of plasticizers. Furthermore, this invention permits the use of inherently tacky fibres and fibres which become inactivatable with time, and which, by reason of such characteristics, could not be formed, shipped or manipulated in conventional textile or felting operations. Since the potentially adhesive material is in fibrous form, there is no loss of material during the fabrication of the fibrous structures as would be the case if such adhesive material were employed in the form of particles or powder. In the manufacture of textiles the present invention simplifies the fibre mixing step since no carding of the-fibre mixture is necessary. Further, the potentially adhesive fibres do not have to be of the same length or denier as thetextile fibres. In the manufacture of felts the present invention permits the direct manufacture of such products with the elimination of iulling, pounci g, wetting and other costly hand operations.

The present invention enables improved felts to be made from various natural or synthetic fibres and filaments which are smooth-surfaced and/or relatively straight and which consequently do not felt readily.

Since certain changes in carrying out the above process, which embodies the invention may be made without departing from its scope, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

The fibrous products disclosed herein are claimed in my co-pending application Serial No. 511,024 filed November 20, 1943, as a continuation-in-part of the present application.

I claim:

1. In a process for producing a felted fibrous product, the steps comprising forming potentially adhesive fibres by dispersing a potentially adhesive organic plastic fibre-forming material into a gaseous atmosphere in the form of a multiplicity of discontinuous fibres, dispersing into said gaseous atmosphere a multiplicity of discontinuous non-adhesive, organic fibres, depositing said mixture of fibres upon the surface of a perforated mold while applying suction to the underside of said mold and activating said potentially adhesive fibres in said deposited mass and subjecting the mass to pressure.

2. In a process for producing a fibrous product, the steps comprising associating a multiplicity of discontinuous, potentially adhesive, organic plastic fibres, concurrently with their formation, with a multiplicity of discontinuous, non-adhesive, organic fibres to form a fibrous product adapted to be treated to activate said potentially adhesive fibres in said product without damage to said nonadhesive organic fibres to bind fibres in said product.

3. In a process for producing a fibrous product, I

the steps comprising associating a multiplicity of discontinuous, potentially adhesive, organic plastic fibres, concurrently with their formation, with a multiplicity of discontinuous, non-adhesive, organic fibres to form a fibrous product; and activating the potentially adhesive "fibres in said product without damage to said non-adhesive organic fibres to bind fibres in said product.

4. In a process for producing a fibrous product, the steps comprising associating a multiplicity of discontinuous, potentially adhesive, organic plastic fibres, concurrently with their formation, with a multiplicity of discontinuous, non-adhesive, organic fibres; fabricating said fibres into a fibrous product in which said potentially adhesive fibres and said non-adhesive fibres are intermixed to form a product adapted to be treated to activate said potentially adhesive fibres in said product without damage to said non-adhesiv organic fibres to bind fibres in said structure,

5. In a process for producing a fibrous product, the steps comprising forming a potentially adhesive, fibre-forming, organic plastic material into a multiplicity of discontinuous fibres; associatin said multiplicity of fibres concurrently with their formation with a multiplicity of discontinuous, non-adhesive, organic fibres; fabricating said fibres into a fibrous structure in which said potentially adhesive fibres and said non-adhesive fibres are intermixed;' and activating the potentially adhesive fibres in said product without damage to said non-adhesive organic fibres to bind fibres in said structure.

6. In a process for producing a fibrous product,

the steps comprising dispersing into a fluid medium a potentially adhesive, fibre-forming, organic plastic material to form a multiplicity of discontinuous, potentially adhesive fibres; associating said potentially adhesive fibres, concurrently with their formation, with a-multiplicity of discontinuous, non-adhesive, organic fibres; and fabricating said fibres into a fibrous structure in which said potentially adhesive fibres and said non-adhesive fibres are intermixed to form a product adapted to be treated to activate said potentially adhesive fibres without damage to said nonadhesive, organic fibres to bind fibres in said structure.

'7. In a process for producing a fibrous product, the steps comprising dispersing into a gaseous medium a potentially adhesive, fibre-forming, organic plastic material to form a multiplicit of discontinuous, potentially adhesive fibres; associating said potentially adhesive fibres, concurrently with their formation, with a multiplicity of discontinuous, non-adhesive, organic fibres; fabricating said fibres into a fibrous structure in which said potentially adhesive and non-adhesive fibres are intermixed; and activating the potentially adhesive fibres in said product without damage to said non-adhesive, organic fibre to bind fibres in said structure.

8. In a process for producing a fibrous product, the steps comprising dispersing a potentially adhesive, fibre-forming, organic plastic material in the form of multiplicity of discontinuous, potentially adhesive fibresinto a fiuid dispersion of a multiplicity of discontinuous, non-adhesive, organic fibres; and fabricating said fibres into a fibrous structure in which said potentially afhesive fibres and said non-adhesive fibres are intermixed to form a product adapted to be treated to activate said potentially adhesive fibres without damage to said non-adhesive organic .fibres to bind fibres in said structure.

9. In a process for producing a fibrous product, the steps comprising dispersing a potentially adhesive, fibre-forming, organic plastic material in the form of a multiplicity of discontinuous, potentially adhesive fibres into a gaseou dispersion of a multiplicity of discontinuous, non-adhesive, organic fibres; fabricating said fibres into a fibrous structure in which said potentially adhesive fibres and said non-adhesive fibres are intermixed; and activating the potentially adhesive fibres in said product without damage to said non-adhesive, organic fibres to bind fibres in said structure.

10. In a process for producing a fibrous product, the steps comprising dispersing a potentially adhesive, fibre-forming, organic plastic material in the form of a multiplicity of discontinuous, potentially adhesive fibres into a liquid containing a suspension of a multiplicity of non-adhesive, organic fibres: and fabricating said fibres into a of. discontinuous, potentially adhesiyefibre's by fibrous structure in which said potentially adhesive fibres and said non-adhesive fibres are intermixed to form a product adapted to be treated to activate said potentially adhesive fibres withp out damage to said non-adhesive organic fibres to bind fibres in said structure.

11. In a process for producing a fibrous product, the steps comprising forming a multiplicity of discontinuous, potentially adhesive fibres by dispersing a composition comprising a potentially adhesive, fibre-forming, organic plastic material dissolved in a volatile solvent into a gaseous atmosphere in the form of fibres, said atmosphere being heated sufiiciently to evaporate said solvent; associating said potentially adhesive fibres, concurrently with their formation, with a multiplicity of discontinuous, non-adhesive, organic fibres; and fabricating said fibres into a fibrous structure in which said potentially adhesive fibres and said nong-adhesive-fibres are intermixed to form aproductadaptiedtdibe treated to activate said po entially adhesive fibres: without damage to aid'non-adhesive organic fibres to bind fibres insai'dstruz ture. r

l2. a process for producing'a fibrous product, the stepscomp'rising forming a "multiplicity dispersinglaipotentially' adhesiv fibre-tanning, organic plastic material into a phere in the-iorm'oi' fibres aseous atmosphere a 'multip 011$. non-adhesi e said two types ot gg rs'ed fibr atmosphere;--permitti ng th V ia commingled condition; andiab eating saidifibres into a fibrous str'ucture'in whichsaid; potentially adhesive fibres and amn'on-adhes e fi intermixed to form'aproduct adapte ed to activate saidpotentially' ad without damage to said non-fadhesiv eforganic fibres to bind fibres in said ,s'tructure'.' 13. In a process for producing a fibrous product, the steps comprising forming a multiplicity of discontinuous, tacky fibres by disperslng apotentially adhesive, fibre-forming, organic plastic material into a gaseous atmosphere; and associating said fibres with a multiplicity of discontinuous, non-adhesive, organic fibres, while said fibres are tacky to form a 'fibro'usproduct, in which the potentially adhesive fibres bind fibres in said structure.

14. In a process for producing a fibrous product, the steps comprising carding-discontinuous, non-adhesive, organic fibres; dispersing intoa gaseous atmosphere a potentially adhesive, fibre forming, organic plastic material to form a multiplicity of discontinuous, potentially adhesive fibres; depositing on the carded fibres while in web form a multiplicity of said potentially adhesive fibres, concurrently with their formation; and fabricating said fibres into a fibrous structure in which said potentially adhesive fibres and sad non-adhesive fibres are intermixed to form a product adapted to be treated to activate said potentially adhesive fibres without damage to said non-adhesive, organic fibres to bind fibres in said product.

15. In a process for producing a fibrous product, the steps comprising carding discontinuous, non-adhesive, organic fibres; dispersing into a gas a potentially adhesive, fibre-forming, organic plastic material to form a multiplicity of discontinuous, potentially adhesive fibres; depositing on the carded fibres while in web form a multiplicity of said potentially adhesive fibres, concurrently with their formation; and converting said web into a yarn comprising a plurality of intermixed potentially adhesive and non-adhesive fibres adapted to be treated to activate said potentially adhesive fibres without damage to said non-adhesive organic fibres to bind fibres in said yarn.

16. In a process for producing a fibrous product, the steps comprising dispersing, into a fluid at least two types of fibre-forming organic plastic materials to form a multiplicity of discontnuous fibres; associating said two types of fibres together, concurrently with their formation; fabricating said fibres into a fibrous structure in which said two types of fibres are intermixed; and activating one of said types of fibres to bind fibres in said product by a treatment which does not damage or render adhesive said other type of fibre.

17. In a process for preparing a fibrous product, the steps comprising dispersing into a fluid medium a potentially adhesive, fibre-forming, organic plastic material to form a multiplicity of discontinuous, potentially adhesive fibres; associating said potentially adhesive fibres, concurrently with their formation, with a multiplicity of organic, paper-making fibres; and sheeting said fibres into a paper product adapted to be treated to activate said potentially adhesive fibres in said product wit. rout damage to said organic paper-making fibres to bind fibres in said product.

18. In a process f r producing a fibrous product, the steps compnsing dispersing a po entially adhesive, fibre-forming, organic plastic material in the form of a multiplicity of discontinuous, potentially adhesive fibres into a water suspension of a multiplicity of organic paper-making fibres; removing water from said suspension to deposit a mixture of said potentially adhesive and said non-adhesive fibres in the form of a paper sheet; drying said sheet; and activating the potentially adhesive fibres in said sheet without damage to said organic paper-making fibres to bind fibres in said sheet.

19. In a process for producing a fibrous product, the steps comprising forming a multiplicity of discontinuous tacky fibres by dispersing a potentially adhesive, fibre-forming, organic plastic material into a gaseous atmosphere; dispersing a multiplicity of discontinuous, non-adhesive, organic fibres in the same gaseous atmosphere; bringing non-adhesive fibres and potentially adhesive fibres into contact in said dispersion while said potentially adhesive fibres are tacky to form a fibrous product in which the potentially adhesive fibres bind fibres in said structure.

20. In a process for producing a fibrous prodduct, the steps comprising forming a web of discontinuous, non-adhesive, organic fibres; dispersing into a gaseous atmosphere a potentially adhesive, fibre-forming, organic, plastic material to form a multiplicity of discontinuous, potentially adheslve fibres; depositing on said web a multiplicity of said potentially adhesive fibres concurrently with their formation; and fabricating said fibres into a fibrous structure in which said potentially adhesive fibres and said non-adhesive fibres are intermixed to form a product adapted to be treated to activate said potentially adhesive fibres without damage to said non-adhesive organic fibres to bind fibres in said product.

CARLETON S. FRANCIS, JR.

Disclaimer 2,357,392.0arleton 5'. Francis, Jr., Pine Orchard, Conn. PROCESS FOR PRODUCING Fnmous PRODUCTS. Patent dated Sept. 5, 1944. Disclaimer filed July 12, 1949, by the assignee, American Viscose Corporation.

Hereby disclaims from the specification the following: Page 1, column 2, line 23, the words a fluid except when the fluid is a gas. Page 1, column 2, line 36, the words a fluid, preferably.

Page 3, column 1, line 17, the words a fluid, e. g. a liquid or.

Page 4, column 1, line 74, to page 4, column 2, line 20, the paragraphs reading:

As an alternative to the process illustrated in Fig. 2, the fibre-forming material may be dispersed into a liquid such as water or other suitable coagulant of the fibreforming material. In this case a current of liquid or air is brought to bear on the stream of fibre-forming material so as to disperse the stream into a multiplicity of fibres as in the case of dispersion into a gaseous atmosphere. Non-adhesive fibres may be present or may be concurrently passed into the liquid so that the mixing of the fibres occurs concurrently with the formation of the potentially adhesive fibres, the mixture of fibres being continuously fabricated into a fibrous structure in a known manner but including the novel steps of this invention.

In this manner, the potentially adhesive fibres may be dispersed in an aqueous suspension of paper-making fibres as in the head box of a Fourdrinier of cylinder paper machine from which box the suspension of fibres is delivered to the forming-wire of the paper machine.

Also disclaims: I

From the scope of claims 2, 3, and 4, all processes except those in which the multiplicity of discontinuous, potentially adhesive, organic plastic fibres are formed in a gaseous atmosphere.

From the scope of claim 5, all processes except those in which the potentially adhesive, fibre-forming, organic plastic material is formed into a multiplicity of discontinuous filaments in a gaseous atmosphere.

From the scope of claims 6 and 17, all processes except those in which the potentially adhesive, fibre-forming, organic plastic material is dispersed into a gaseous atmosphere to form a multiplicity of discontinouus potentially adhesive fibres.

From the scope of claim 8 all processes except those in which the potentiall' adhesive, fibre-forming, organic plastic material is dispersed in the form of a mul tiplicity of discontinuous fibres into a gaseous dispersion of a multiplicity of discontinuous, non-adhesive, organic fibres.

From the scope of claim 16, all processes except those in which at least two types of fibre-forming organic plastic materials are dispersed into a gas to form a multiplicity of discontinuous fi res.

Also hereby enters this disclaimer as to claims 10 and 18 of said patent.

[Oflicial Gazette August 9, 1949]

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