US2810645A

US2810645A - Method of making textile webs

Info

Publication number: US2810645A
Application number: US143369A
Authority: US
Inventors: Francis D Houghton
Original assignee: American Viscose Corp
Current assignee: Akzo Nobel UK PLC
Priority date: 1950-02-09
Filing date: 1950-02-09
Publication date: 1957-10-22
Anticipated expiration: 1974-10-22

Description

United States Patent METHOD OF MAKING TEXTILE WEBS Francis D. Houghton, Fairville, Pa., assignor to American Viscose Corporation, Wilmington, Del., a corporation of Delaware No Drawing. Application February 9, 1950,

. Serial No. 143,369

12 Claims. (Cl. 9 2-3) ever, in order to produce a carded textile web consisting V entirely of synthetic or artificially formed fibers, such as regenerated cellulose fibers, for example, it is desirable to use fibers having a length of at least one inch since shorter fibers are more difficult to card. Synthetic or artificially formed fibers shorter than one inch cannot be carded and/or combed successfully unless a special cloth is used on the card or a substantial proportion of longer carrier fibers are used. This has imposed limitations on the fibers which can be used in producing textile webs by procedures involving combing and carding. Moreover, in the webs coming from the carding machine, the fibers are parallelized in the direction of the longifor the fibers in aqueous media.

tinuous film or coating between and over the fibers and/ or over the surfaces of the web.

There have been, then, two obstacles to the production of porous water-laid textile webs characterized by high wet strength and consisting of, or comprising a major proportion of, synthetic or artificially formed fibers: impossibility or extreme difiiculty of dispersing the synthetic or artificially formed fibers in water in the absence of a dispersing agent for the fibers, and the lack of a waterinsoluble dispersing agent for the fibers which does not reduce the porosity of the textile web.

Both problems are solved by the present invention which has as one object to provide coherent, strong, textile webs consisting of, or predominantly of, synthetic, or artificially formed fibers and characterized by high strength in the wet state. Another object of the invention is to provide a method for producing such textile, webs, using conventional paper-making equipment. A

further object is to provide a new bonding agent for synthetic or artificially formed fibers which occurs at the intersections of the fibers in the web in particulate, discontinuous condition, and which is also a dispersing agent A specific object is to provide coherent, strong, highly porous and absorbent water-laid textile webs all of the fibers of which are regenerated cellulose fibers.

tudinal dimension of the web, and the structure of the web is inherently weak and the web is relatively easily torn apart or shredded when subjected to tension in any direction as it comes from the card, which makes it difficult to handle such webs.

Heretofore, useful textile webs consisting entirely of synthetic or artificially formed fibers having a length of A or above could not be formed by depositing such fibers from a water dispersion on the screen of a conventional paper-making machine. The synthetic or artificiallyformed fibers of such a length agglomerate in flocs or clumps in water and cannot be dispersed uniformly in water or aqueous media under ordinary conditions. If they are mixed or beaten with water and deposited on a paper-making screen, the web comprises thick and thin portions as a result of the presence of the clumps therein. Furthermore, a coherent web is not obtained, since the artificial or synthetic fibers do not fibrillate and do not interlock together. A product obtained by depositing water containing fibers all of which are regenerated cellulose fibers on a screen such as is used in papermaking has to be picked ofi the screen in fragments, regardless of the length of the regenerated cellulose fibers.

In order to produce a coherent textile web comprising synthetic or artificially formed fibers by separation of the fibers from aqueous media, an extraneous dispersing agent must be present in the dispersion. However, previously available dispersing agents which might be considered for use in making a textile web comprising synthetic or artificially formed fibers, using conventional paper-making equipment, have had one or both of two major disadvantages in that the agent is water-soluble and thus is not suitable for use when a web of high or even good wet strength is required, or it has been of a character such that it materially reduces the porosity of'the textile web by partially closing the interstices between the fibers or destroys the porosity by forming a con- In accordance with the invention textile webs having novel characteristics are made on paper-making equipment by mixing synthetic or artificially formed fibers having a length of from seven-sixteenths of an inch to one inch with an aqueous medium containing dispersed gel particles of a Water-insoluble, alkali-soluble cellulose ether which is a dispersing agent for the fibers, separating the fibers carrying the ether from the dispersion to obtain a textile web of randomly intermingled fibers, drying and pressing the web, and at some time prior to the final drying and pressing, precipitating the cellulose ether particles on the surfaces of the fibers.

In the preferred embodiment, the fibers are mixed with the aqueous alkaline dispersion of the waterinsoluble,

alkali-soluble cellulose ether in the beater of a papermaking machine, and the dispersion, preferably after dilution with water, is continuously fed to the screen of a' conventional paper-making machine. By the practice of this invention it is possible, for the first time in the history of the art, to produce, continuously, extremely wide,

coherent, strong, highly porous textile webs of indefinite In preparing the alkaline dispersion of the water-insoluble, alkali-soluble cellulose ether, it is preferred to dissolve the ether in aqueous alkali of from 1 to 8% concentration, or in solutions of higher concentration which are subsequently diluted, and to add the solution thus obtained to water in the beater. Since the ether is insoluble in water and in aqueous alkaline solutions of less than 1% concentration, the addition of the solution to the water in the beater results in dispersion of the ether through the dilute aqueous alkaline medium in the form of extremely fine colloidal gel particles. I have found that the dispersed cellulose other is a dispersing agent for synthetic or artificially formed fibers, which can be uniformly distributed through the ether dispersion without subjecting the mass to beating, using the beater roll previous lackof a satisfactory water-insoluble dispersing 3 agent for thesefibersp The particulate water-insoluble,"--'

Patented Oct. 22,1957 v alkali-soluble cellulose ethers are both dispersing agents for the fibers in aqueous media, and water-insoluble binding agents for the fibers in theifinished textile web. The fibers, vsuch as regenerated cellulose fibers. for example, are distributed uniformly throughlth'eiaqueouealkaline medium containing the I dispersed waterrinsoluble; alkalisoluble cellulose =ether -by -mixing, rwithout thexfor mation.

to .disperse the syntheticor artificiallyaformed Ffibers .-in the-absence of the dispersedether (another-dispersing. agent. The water-laid textile webs -comprisingjfibers all of which are synthetic or=artificially-formedfibersare produced without beating. Ifiit is desired-to include a small proportion of otherfibers, these-may be ibeaten prior-to introduction of .thesynthetic orartificially formed fibers, or they may be -beaten. in.a separate beater .and introduced into the aqueous alkaline ether dispersion simultaneously with thesynthetic or artificially formed fibers.

.It is possible to precipitate the cellulose ether particles on the surfaces of the fibers by various .methods, at various stages in the -manufacture of the webs. In the presently preferred modification, however, thecellulose ether particles are precipitated on the fibers'in the beater, preferably, but not necessarily, prior to diluting the fibers dispersion to thefinal desired fiber concentration. This precipitation is accomplishedby adding any suitable acid, or acid salt, 'which does not decompose the ether and functions to adjust'theipH of the dispersion to the acid side, to the beater, after the synthetic or artificially formed fibers have been dispersed. The precipitation .results in the agglomeration of the waterinsoluble, alkali-soluble cellulose ether gel particles into particles of larger than colloidal size. The particles adhere to the surfaces of the fibers in the particle form and when the dispersion is deposited on a paper-making screen, for example, the fibers are laid downin. randomly intermingled condition and bonded together in that condition, at their points of intersection, by the particles of the cellulose ether. The water-insoluble, alkali-soluble cellulose ethers are not thermo-plastic and do not flow when the textile web is subjected to beat and pressure, during finishing. Therefore, the ether particles precipitated on the 'fibers in the beater, remain as particles in the finished textile web. The .particles, occurring at the intersection of the randomly intermingled fibers, .do not close or seriously obstruct .the interstices between the fibers, with the result that .the textile -web' as produced has substantially the same porosity as if the particulate cellulose 'ether were not present and the textile web consisted entirely of the synthetic or artificially formed fibers.

The aqueous dispersion containing the synthetic -or artificially formed fibers carrying the precipitated, particulate water-insoluble, alkali-soluble cellulose'ether may be formed into a textile web by the use .of conventional paper-making machines -of various types, snch'as the Fourdrinier, or Harper, single cylinder of Yankee multi-vat machine, mould, presse pate, or the like. Thick textile webs may be obtained bypassing a relatively thin textile web of fibers carrying the precipitated cellulose ether (which webhas been formed on a cylinder and couched to the felt of a cylinder paper-making machine, or run from the apron onto the wire and couched to the felt of a Fourdrinier paper-making machine) between press rolls with another relatively thin textile web of fibers carrying the precipitated ether, before the webs are completely dried, repeating the procedure until a sufiicient number of webs have been built up, and then subjecting the assembled plies or webs to heat and pressure.

Instead of. precipitating thetdispersed cellulose ether particles on the fibers in the-.beater, itmay becarried in the .form of the colloidal. gel. particles "on ithe lfibers throughv theforming steps, .andisubsequently fixed on thethe etherrnay bepartially dried'arrd then passedthrough or immersed vin 'an .:aqueous acid or acidv salt.-solution which precipitatesithe etherzoirthe fibers, or'the Webfmay be subjected to a suitable acid gas or vapor such'as-moist sulfur dioxide to precipitate the ether. Subsequently, the web is washed free of acid, dried, andsnbjected to pressure. In another embodiment, the cellulose ether is dissolved in aqueous alkali, formaldehyde is added, and an acid, for instance sulfuric acid is added, the resulting acidic formaldehyde-containing cellulose ether-containing medium, being then introducedinto water. in'thebeater.

This has the advantage that the celluloserether containing medium added to the beater has an acid :pH, which: may be desirable, in somecases. No =furtheracid treatment is required toprecipitate the ether, when the acid -(or acid salt) is mixed with the ether and formaldehyde prior to adding the mixture to the beater.

The term water-insoluble, alkali-soluble cellulose ether is intended to include ethers whicharelinsolublein water, but soluble in aqueous alkaline solutions of from 1' to 8%, preferably 4 to. 8% alkali, atroomternperature or at reduced temperature, for example, in solutions of a strong alkali such as sodium, potassium, or lithium hydroxide. Included are simple alkyl ethersgcarboxyalkyl ethers, hydroxyalkyl ethers, mixed alk-y-l h-ydroxyalkyl ethers, mixed alkyl carboxyalkyl ethers, and the alkali metal salts of the carboxyalkyl ethers.

The proportion of water-insoluble, alkali-soluble'cellulose ether added to the water in. the beater may vary somewhat, but'usually is such that the aqueouszmedium in the beater contains from 0.02% to 0.5% of the ether, on the weight of the water, the concentration of alkali in the beater being such that, prior to any addition of acid for precipitating the ether, the dispersion of the ether has a pH of from 10 to 14.

Any suitable acid or acid salt may. be added to the beater, preferably as an aqueous solution,.for precipitating the cellulose ether particles on the fibers. Sufiicient acid or acid-forming salt is added to the beater, after'the fibers are dispersed, to giveapH of'62to 7. Examples of. suitable acids are sulfuric, boric, acetic, iandhydrochloric acids. Examples of suitable salts 'are sodium dihydrogen' phosphate, sodium .bisulfa'te, ammonium sulfate, and. aluminium sulfate. .As illustrative, aqueous solutions of from 0.2 to 0.4% sulfuric acid may be used.

.If the acid solution :is added to the mass prior'to final dilution, no special treatment is required to neutralize the acid, the concentration of acid being insufficient to damage any regenerated cellulose fibers present. However, if the acid is added after the dispersion has been diluted to the final, desired fiber concentration, a larger 7 amount of' acid is required to bring the mass to the desired pH'and it may be desirable to add a neutralizing agent, for example an aqueous solution of sodium carbonate to neutralize the acid and adjust the pH of the dispersion to 6 to 7..

The synthetic or artificial fibers from which the textile web is formed have a length of from seven-sixteenths inch 'shredding in the transverse direction, in 'both the dry andwet states, which'is greatly'superior to the resistance of carded webser so-callednon-Wr/oven fabrics made by processes involving a carding operation, comprising longer, cardable fibers, as a result of the randomly intermingled condition of the fibers in the water-laid web, which imparts strength to the web in the transverse direction. These water-laid webs have tensile strengths and resistance to tearing and shredding force applied in any direction which compare favorably to those properties of belt-like products obtained by depositing fibers from an inert fluid conveying medium, in which random distribution of the fibers is at a maximum, and in which the fibers are autogeneously bonded together or bonded by means of an extraneous binder.

The synthetic or artificial fibers, may be formed from any suitable fiber-forming material such as regenerated cellulose; cellulose acetate; casein; high molecular Weight synthetic linear polyamides or polyesters; copolymers of vinyl chloride and vinylidene chloride; polyethylene; polyacrylonitrile; copolymers of acrylonitrile or its homologues with one or more other polymerizable substances containing the linkage C=C including copolymers of acrylonitrile with one or more of the following: vinyl acetate, vinyl chloride, styrene, isobutylene, vinyl-wchloracetate, etc., especially those acrylonitrile polymers containing at least 70% acrylonitrile in the polymer molecule. The synthetic or artificial fibers may be thermoplastic and convertible to an adhesive condition by heat, so long as the temperature at which their latent adhesive properties are developed is above the temperature at which the textile web is treated to fix the particulate water-insoluble, alkali-soluble celluloseether, if fixing is by heat, and above the temperature at which the web is dried and pressed.

By selection of the synthetic or artificial fibers having a length of from seyen-sixteenths inch to one inch, and the proportion of water-insoluble, alkali-soluble cellulose ether added to the beater, the characteristics of the final textile web may be varied. Textile webs or non-woven fabrics which are tough, flexible, and softto the touch may be produced, or the web may be relatively stiff and resilient. The texture of the web is also influenced by the method of precipitating the particulate ether on the fibers, since those textile webs consisting of fibers bonded by ether particles precipitated in the beater, by acid, have a crisper hand or feel than do the webs in which the fibers are bonded by ether particles precipitated on the fibers of the web by heat, for example, during drying and pressing of the web. ,A preferred modification contemplates a thin, tough, water-laid textile Web or non-woven fabric formed exclusively of regenerated cellulose fibers having a length of from seven-sixteenths of an inch to one inch bondedat theirvpoints of intersection in the randomly intermingled condition resulting from formation of the Web on paper-making equipment by the particulate Waterinsoluble, alkali-soluble cellulose ether, and characterized by high wet strength, porosity, high absorptivity for liquids, excellent retention of absorbed liquids, softness, drape, and soft, pleasing hand or feel.

The textile webs of the invention are useful for many purposes. They may be used for general textile purposes.

Also, they maybe used as absorbent pads for use in permanent waving, as linings for pocketbooks and the like, as disposable diaper fillers, in surgical tampons, as absorbent cleansing pads, in fabric laminates, etc. The textile webs possess excellent filtering characteristics, those formed from the synthetic resins being especially adapted to this use because of their resistance to common solvents and bacterial or mold attack. The webs have a smooth surface, and may be coated to provide coated fabrics having an absorbent reverse side. The webs can be combined with a woven gauze or other fabric of conventional type to provide an excellent base for dyeing,

printing, surface coating and other special. treatments. I

A thin water-laid web, for example one consisting of randomly intermingled regenerated cellulose fibers bonded at their points of intersection by the particulate 6 cellulose ether may be coated with a clear. resin, for example, a melamine-formaldehyde resin, to provide a transparent web or sheet which can be used as an overlay for the printed surface sheet of laminated articles, such as tabletops, bartops, etc. which are subject to wear and marking in service because, due to its high transparency, the sheet does not obscure the printed surface sheet when it is treated with the resin and fixed to the laminate. Textile Webs made in accordance with the invention may be coated with a resin and used as light Weight display fabrics, shelf and table coverings, place mats, linings for luggage or instrument cases, etc. The webs may also be used as wrappers and packaging materials for various articles. For example, a water-laid textile web in accordance with the invention may be coated with polyvinyl butyral to provide a wrapper for meats. The webs may also be used for packaging particulate solid materials such as dyes, powdered food extracts, repellents such as moth crystals, powdered perfumes, etc., since although they are porous and liquid and gas permeable, solid particles do not pass through them. The webs as such may be used as protective wrappers for wound packages of filamentary material to protect the package during liquid after-treatments or during shipment, or they may be used as a base for shrinkable wrappers for packages of regenerated cellulose which wrappers are coated with a cellulosic material such as viscose or which are provided with localized deposits of viscose, or of a Water-insoluble, alkali-soluble cellulose ether, or of cellulose acetate, and shrink with the package during drying thereof after the usual after-treating liquids have been applied to the package. The Water-laid textile webs can be used for many of the purposes for which conventional fabrics are used, and for purposes for which a carded web or nonwoven fabric is suitable, and have the advantage over such carded webs that they can be readily made from synthetic or artificial fibers of less than normal cardable length, and exhibit good tensile strength and resistance to tearing and shredding in both the transverse and longitudinal directions, and in both the dry and wet states.

The following examples are illustrative of the production of water-laid textile webs, in accordance with the invention. In the examples, standard viscosity is the viscosity of a solution of the ether containing water, 6% cellulose ether, and 9% sodium hydroxide by weight, measured at 25 C., and expressed as a multiple of the viscosity of glycerol, also measured at 25 C.

Example I A water-insoluble, alkali-soluble hydroxyethyl cellulose having a standard viscosity of 6, and an average degree of substitution of 0.20 ethylene oxide group per glucose unit is dissolved in 8% sodium hydroxide to obtain a 6% solution of the ether, and the solution is mixed with water in the beater of a paper-making machine to obtain a dilute aqueous alkaline dispersion containing 0.2% (based on the weight of the water) of the ether in the form of very fine colloidal gel particles. 1.5% (based on the weight of the water) of regenerated cellulose fibers cut to a length of inch are added. After thorough mixing (but without subjecting the mass to a beating action) suflicient concentrated sulfuric acid of 1.84 specific gravity is added to give a final dispersion having a pH of 6-7. The acid agglomerates the dispersed colloidal ether particles into larger than colloidal gel particles which adhere to the surfaces of the fibers in the particle form. The dispersion,

is then diluted with Water to 0.2%0.002% fiber content and sheeted on a Fourdrinier paper machine. The textile web thus formed is passed over drying cans at C. and then to the calender rolls, between which it is subjected to a pressure of 1000 lbs/sq. in. The final pressed or calendered web is a soft, light weight, readily wettable, porous textile web consisting of randomly intermingled regenerated cellulose fibers bonded at their points of intersection by particles of the acid-precipitated water-insoluble, j

alkali-soluble cellulose ether. The random distribution of the-fibers in the web is readily discernible by the naked eye. This textile web exhibits high dry and wet strengths, and excellent resistance to tearing or shredding.

Example 11 A web produced as in Example I is coated with a clear melamine-formaldehyde resin precondensate and dried. The resulting coated web is clear and transparent.

Example 111 Example I is repeated except that the regenerated cellulose fibers have a length of one-halfinch. A textile web characterized by excellent'dry and wet strength and resistance' to tearing and shredding force is obtained.

Example '1 V A'water-insoluble, alkali-soluble hydroxyethyl cellulose having a standard'viscosity of 2, and an average degree of substitution'of 0.36;40 ethylene oxide groupper glucose unit, is dissolved in 8% sodium hydroxide to produce a 6% solution of the ether. The solution is mixed with water in the beater of a paper-making machine. There is thus-obtained a dilute aqueous alkaline-medium containing'0.2'% (on the weight of the water) of the ether in the form of extremely fine colloidal gel particles. Regenerated cellulose fibers having a length of one-half inch are added, in an amount of 1.5% (on the weight of the water) and uniformly distributed through the dispersion, using the beater roll as a'mixer. The dispersion isdiluted with water to 0.02% fiber content,-and sheeted on a'Fourdrinier machine. The textile web thus obtainedisrpassed between rolls heated to a temperature of 85 to 150 'C., to precipitate the particulate hydroxyethyl cellulose and dry the web. The web is then finished by passing it between calender rolls at a pressure of 1000 lb./ sq. in.

Example V A textile web is preparedas in Example IV. The web is partially dried in air, passed through aqueoussulfuric acid toprecipitate'the particulate hydroxyethyl cellulose, passed. through .a water-bath to remove acid, andthen passed over drying cans at 14'5'C. The web is then calendered ata pressure of l'0O0'lb./sq. in.

Example -VI' A water-insoluble, alkali solublehydroxyethyl cellulose ether having a standard viscosity of 6, and an average degree of substitution of 0.36-0.40ethylene oxide group per 'anhydroglucose unit is dissolved in 8% aqueoussodium hydroxide. Tenparts of the-solution-are diluted by stirring'with '14 partsof ice and 24zparts of coldwater. Sixip'arts'oflformaldhyde (as 37% commercial formalin) areadded,'at a'temperature below 46 F. 'To this, are added6 parts ofi20'% sulfuric'acid,thepH'being adjusted to 2.0. The resulting mixture is added. to cold water-in the beater of apaper-making machine,.a dispersionhaving a pH of 210 being'finally obtained. After the mixture .has been stirred, 1.5% 'ofregenerated cellulosefibers havinga length of seven-.sixteenths of'an inch are added,.and.distributedthrough the medium .by mixing, .us'ing the beater roll as 'aimixer. The dispersion -is diluted-to 0.2% fiber content, and sheeted on a. Fourdrinier machine to produce a textile web .in which the randomly distributedregeneratedcellulosefibers arebonded attheir pointsoflintersectionby'theprecipitated cellulose ether particles.

Since variations and modifications may be made in practicing thefinvention as described in specific detail herein,'withoutdeparting' from its spirit and scope itis tobe. understood'that-the invention is=not tobe limited except as defined byn'the appendedclaims.

I claim:

1., A methodof. making. coherent, strong, textile webs from .fibersall of which-are extruded synthetic, artificially formed, non fibrillating organic fibers having a length of from seven-sixteenths of an inch to one inch which comprises mixing such fibers with an aqueous alkaline medium of less than 1 alkali concentration and containing, as a fiber dispersing agent, dispersed colloidal gel particles of a water-insolublehydroxyethyl cellulose to disperse the fibers through the medium without subjecting them to beating,.the hydroxyethyl cellulose being soluble in aqueousalkaline solutions of between 1% and 8% alkali concentration,separating-the fibers carrying the hydroxyethyl cellulose particles from the aqueousalkaline medium to obtain a textile web of randomly intermingled fibers, drying the weband, at-some time between mixing of the fibers with theaqueous alkalinemedium and final finishing of the web,- precipitating the hydroxyethyl cellulose on the surfacesof thefibers.

2. The method according to claim 1 characterized in that the water-insoluble alkali-solublehydroxyethyl cellulose particles are'fixed on the surfaces of the fibers by heat applied to the textile web.

3. The method according to claim 1 characterized in that the water-insoluble alkali-soluble hydroxyethyl cellulose particles are precipitated on the surfaces of the fibers under acidic conditions.

4. A method of making coherent,,strong, textile webs from fibersall of which are extruded synthetic, artificially formed, non-fibrillating'organicfibers'having a length of from seven-sixteenths of an inch to'one inch which comprises mixing-such fibers with an aqueous alkaline medium of less-than 1% alkali concentration and containing, as a fiber dispersing agent,dispersed colloidal 'gel particles of a water-insoluble hydroxyethyl cellulose to disperse the fibers through :the aqueousalkaline medium without subjecting them to beating, the hydroxyethyl cellulose being soluble in aqueous alkaline solutions of between 1% and 8% --alka1i concentration, acidifying the medium to precipitate the hydroxyethyl cellulose on the surfaces of thefibers-in the form of particles of larger than colloidal size, dilutingthe acidified medium with water, continuously feeding the diluted medium to the screen of a paper-making machine to form a textile web of-randomly intermingled fibers carrying the discrete precipitated hydroxyethyl cellulose particles, and drying the web to obtain a web in which the fibers are bonded at their points of intersection by the discrete hydroxyethyl cellulose particles.

5. A method of making coherent, strong, textile webs from fibers all of which are extruded synthetic, artificially formed, non-fibrillating organic fibers havingalength of fromseven-sixteeuths of an inch to one inch which comprises mixing such fibers with an aqueous alkaline medium of less than 1% alkali concentration and containing, as a fiber dispersing agent, dispersed colloidal gel particles of a water-insoluble hydroxyethyl cellulose to disperse the fibers in the medium without subjecting them to beating, the hydroxyethylcellulose being soluble-in. aqueous alkaline solutions of-between 1% and 8% alkali concentration, dilutingthe medium with water, continuously feeding the diluted medium -to the screen of a papermaking machine to form a textile-wb'of randomly intermingled fibers carrying discrete particles of the hydroxyethyl cellulose and heating the web-to simultaneously dry the web and -fix -the discrete hydroxyethyl cellulose particles on the surfaces of the fibers in situ in the web.

6. A method of makingcoheren't strong, textile webs from fibers all of which are-extruded synthetic, artificially formed, non-fibrilla'ting organic fibers which comprises adding formaldehyde to a dilute aqueous alkaline medium containing a water-insoluble, alkali-soluble hydroxyethyl cellulose, acidifying the medium, diluting the acidified medium with water, mixing extruded synthetic, artificially formed, non-fibrillating fibers having a length of from seven-sixteenths of aninch to'one inch with the diluted acidified aqueous medium to disperse the fibers through the medium without subjecting them to beating, continuously feeding the dispersion to the screen of a papermaking machine to obtain a textile web of randomly intermingled fibers carrying the hydroxyethyl cellulose and drying the web.

7. A method of making coherent, strong, water-laid textile webs from fibers all of which are extruded synthetic, artificially formed, non-fibrillating organic fibers having a length of from seven-sixteenths of an inch to one inch which comprises mixing such fibers with an aqueous alkaline medium of less than 1% alkali concentration and containing, as a fiber dispersing agent, dispersed colloidal gel particles of a water-insoluble hydroxyethyl cellulose to disperse the fibers through the medium without subjecting them to beating, the hydroxyethyl cellulose being soluble in aqueous alkaline solutions of between 1% and 8% concentration, diluting the aqueous alkaline medium with water, continuously feeding the diluted medium to the screen of a paper-making machine to form a textile web of randomly intermingled fibers carrying discrete colloidal gel particles of the hydroxyethyl cellulose on their surfaces, partially drying the web, passing the web through an acidic medium to precipitate the hydroxyethyl cellulose on the surfaces of the fibers in the form of particles of larger than colloidal size, washing the web, and drying the web.

8. A method of making coherent, strong, textile webs from fibers all of which are extruded synthetic, artificially formed, non-fibrillating organic fibers having a length of from seven-sixteenths of an inch to one inch which comprises mixing such fibers with an aqueous alkaline medium of less than 1% alkali concentration, said medium having a pH between 10 and 14, and containing by weight, based on the weight of the water of the medium, between 0.02% and 0.5% of a Water-insoluble hydroxyethyl cellulose in the form of dispersed colloidal gel particles to disperse the fibers through the aqueous medium without subjecting them to beating, the hydroxyethyl cellulose being soluble in aqueous alkaline solutions of between 1% and 8% alkali concentration, separating the fibers carrying discrete particles of the hydroxyethyl cellulose from the aqueous medium to obtain a textile web of randomly intermingled fibers, drying the web and, at some time between mixing of the fibers with the aqueous alkaline medium and final finishing of the web, precipitating the hydroxyethyl cellulose particles on the surfaces of the fibers.

9. A method of making coherent strong textile webs from fibers all of which are extruded synthetic, artificially formed, non-fibrillating organic fibers having a length of from seven-sixteenths of an inch to one inch which comprises mixing such fibers with an aqueous alkaline medium of less than 1% alkali concentration, said medium having a pH between 10 and 14, and containing by weight based on the weight of the water of the medium, between 0.02% and 0.5 of a water-insoluble hydroxyethyl cellulose in the form of dispersed colloidal gel particles to disperse the fibers in the aqueous alkaline medium without subjecting them to beating, the hydroxyethyl cellulose being soluble in aqueous alkaline solutions of between 1% and 8% alkali concentration, acidifying the aqueous alkaline medium to adjust the pH thereof to between 6 and 7 and precipitate the hydroxyethyl cellulose on the surfaces of the fibers in the form of particles of larger than colloidal size, diluting the acidified medium with water, continuously feeding the diluted medium to the screen of a paper-making machine to form a textile web of randomly intermingled fibers carrying the discrete precipitated hydroxyethyl cellulose particles, and drying the web to obtain a web in which the fibers are bonded at their points of intersection by the discrete hydroxyethyl cellulose particles.

10. The method according to claim 9 characterized in that the fibers are regenerated cellulose fibers.

11. As a new article of manufacture, a coherent strong, porous textile web consisting of a multiplicity of randomly intermingled discontinuous fibers all of which are extruded synthetic, artificially formed, non-fibrillating organic fibers having a length of from seven-sixteenths of an inch to one inch and bonded at their points of intersection into a web by a water-insoluble, alkali-soluble hydroxyethyl cellulose essentially all of which occurs in the web in the form of discrete particles of larger than colloidal size.

12. A new article of manufacture as defined in claim 11 wherein the fibers are regenerated cellulose fibers.

References Cited in the file of this patent UNITED STATES PATENTS 1,829,585 Dreyfus et al. Oct. 27, 1931 1,898,601 Shoemaker Feb. 21, 1933 2,236,545 Maxwell et al Apr. 1, 1941 2,297,248 Rudolph Sept. 29, 1942 2,414,833 Osborne Jan. 28, 1947 2,477,000 Osborne July 26, 1949 2,568,144 Cremer et a1. Sept. 18, 1951 2,572,932 Horsey et al. Oct. 30, 1951 2,626,214 Osborne Jan. 20, 1953 FOREIGN PATENTS 423,471 Great Britain Feb. 1, 1935 530,293 Great Britain Dec. 9, 1940

Claims

11. AS A NEW ARTICLE OF MANUFACTURE, A COHERENT STRONG, POROUS TEXTILE WEB CONSISTING OF A MULTIPLICITY OF RANDOMLY INTERMINGLED DISCONTINUOUS FIBERS ALL OF WHICH ARE EXTRUDED SYNTHETIC, ARTIFICIALLY FORMED, NON-FIBRILLATING ORGANIC FIBERS HAVING LENGTH OF FROM SEVEN-SIXTEENTHS OF AN INCH TO ONE INCH AND BONDED AT THEIR POINTS OF INTERSECTION INTO A WEB BY A WATER-INSOLUBLE, ALKALI-SOLUBLE HYDROXYETHYL CELLULOSE ESSENTIALLY ALL OF WHICH OCCURS IN THE WEB IN THE FORM OF DISCRETE PARTICLES OF LARGER THAN COLLOIDAL SIZE.