Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.

Patents

  1. Advanced Patent Search
Publication numberUS2336797 A
Publication typeGrant
Publication dateDec 14, 1943
Filing dateJun 19, 1939
Priority dateJun 19, 1939
Publication numberUS 2336797 A, US 2336797A, US-A-2336797, US2336797 A, US2336797A
InventorsMaxwell Robert William
Original AssigneeDu Pont
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Felted product
US 2336797 A
Images(1)
Previous page
Next page
Description  (OCR text may contain errors)

Dec. 14, 1943.

R. W. MAXWELL FELTED PRODUCT Filed June 19, 1939 Nix-L11 E1 of E- TLTHETiE'. F'cfl mer' Fih E'PE [Binder] and Higher MEIHJE m1" InEu-aibla F'fh Ers- EEPIEHJE DE Mixture of F-L har's I Math-r2 of Bar flel NiXTuPE of Pi]: as

HE a t-L113 DE Mafi m1 MixTur'E nf Fibers Under Fvessura Polyam z'o e binder 2Z8 Non-fuxz'blq or npn-rglra c Table ceZluZQnc orZZ ire fiber-J R In]: EFT W Naxw all a, d z 201% atente ee. M, 1943 FELTED PRODUCT Robert William Maxwell, Wilmington, Del., as-

signor to E. I. du Pont de Nemours 8.: Company, Wilmington, Del., a corporation of Delaware Application in... 19, 1939, Serial No. 280,016 6 Claims. (01. 154-33) This invention relates to fibrous materials, and more particularly to improved felted products.

This invention has as its object the preparation of new felt compositions having improved physical properties. A further object is the economical manufacture of new and valuable felted products. Other objects will appear hereinafter.

These objects are accomplished by the production of a felted material comprising a binder of synthetic linear polymer and filaments which are substantially unaltered at the softening point of said polymer. A convenient method of obtaining my new products comprises the preparation of a felt by forming a sheet or mat containing a uniform mixture of fusible or heat retractable staple binding filaments prepared from synthetic linear superpolymers and nonfusible staple filaments or staple filaments which soften or retract at temperatures appreciably higher than that of the synthetic binding filaments, and then heating the preformed sheet or mat under pressure at a temperature sufiicient to cause the softening or retraction of the binding filaments without appreciably softening or harming the other filaments. The non-fusible or non-retractable filaments may be cellulosic, wool, hair, glass, etc. In place of the nonfusible filaments it is possible to use filaments of considerably higher melting point than the fusible filaments which are made to soften or retract during the felting operation.

The above mentioned synthetic filamentsforming the binding material are those prepared from the synthetic linear superpolymers which are obtainable from bifunctional reactants as described in Patents 2,071,250, 2,071,251 and 2,130,948. These polymers are capable of being formed by extrusion from melt into filaments which upon cold drawing .show molecular orientation along the fiber axis.

Fig. 1 represents a fiow sheet which indicates the steps used in making my felted product;

Fig, 2 is a sectional view of my new felt; and

Fig. 3 is a similar view showing a greater magnification of the fibrous structure.

In the embodiment shown in the drawing the felt l comprises a compressed mixture of polyamide binder fibers 3 and cellulosic fibers 2.

The following examples, in which the parts are by weight, are illustrative of the practice of this invention:

Example I Filaments were prepared from an amide-ester interpolymer consisting of 15% polyhexamethylene adipamide-85% polyethylene adipate and cut into staple of 1% to 1 inch length. After this staple filament was opened 18 parts of it was mixed thoroughly with 82 parts of cotton fiber by tumbling. This mixture was then carded and matted in the fashion customarily employed in the felting industry. The mat of fibers was placed between two pieces of canvas and the entire assembly pressed for 90 seconds between the platens 'of an hydraulic press at a temperature of about 140 C. and at a pressure of about 1500 lbs. per sq. in. The felt produced by this method had good strength and was suitable for use in various applications as described later.

Example II Filaments were spun from an interpolyamide derived from 40 parts of hexamethylenediammonium adipate and 60 parts of caprolactam. These filaments were cold drawn about 400% and then cut into staple fiber of about 1 inch length. This staple fiber was then mixed with cotton fiber in the same proportions and in the same manner as described in Example I. This mixture of fusible and non-fusible fibers was then carded and felted in the same manner as described above.

Another interpolyamide of this type which is especially useful in making the felted products of this invention is that obtainable from hexamethylenediamine, sebacic acid, and G-aminocaproic acid.

Example III A synthetic fiber spun from polyhexamethylene adipamide was cut into /2 to inch lengths and dispersed in water in a paper beater with the roll at heavy brush for 15 minutes. Twenty-five parts of these beaten fibers (dry basis) were then mixed with 75 parts of kraft fiber and formed into sheets by standard paper-making practice. The sheets were preheated for one minute at 177 C. and then pressed for 30 seconds at a temperature of 177 C. and a pressure of 1700 lbs. per sq. in. The pressed sheets had a higher tearing strength than sheets containing kraft fibers only.

The presence of water in the polyamide fibers lower the temperature at which felting occurs. Water is particularly effective in this connection in the case of the interpolyamide of Example H.

Example IV Similar results were obtained when sheets were prepared in the same manner as described in Example III with the exception that parts of polyhexamethylene adipamide fibers were used with 25 parts of kraft wood pulp fibers.

Example V A mixture of equal parts of polyhexamethylene adipamide fibers about /2 to inch long with the crinkled krtft fibers obtained by the process Example VI Filaments spun from an interpolymer obtained from equimolecular parts of hexamethylenediammonium adipate and decamethylenediammonium sebacate were cold drawn 450% and then cut into lengths of V to 4 inch. Twenty parts of these fibers were then beaten in kg. of water with 40 parts of kraft wood pulp in a paper beater. When the fibers were dispersed sheets were prepared in the usual manner and dried at 90 C. After drying the sheets were subjected to a pressure of 6000 lbs. on an 8 inch square area for 1 minute at a temperature of 160 C. These pressed sheets were tough and pliable and had a tearing strength about three times that of sheets made from kraft fiber alone. This type of polyamide fiber softens over a fairly wide temperature range and is particularly desirable for use in this process because compression of the fibrous mass at the softening temperature is sufiiclent to cause adhesion between the various fibers without -causing the polyamide to liquefy and fill the interstices. This imparts toughness to the sheet without lowering the pliability of the material.

Example VII A mixed fabric containing 25% wool and 75% criniped polyhexamethylene adipamide fiber was subjected to heat and pressure to felt the fibers in this fabric. The fabric responded to this treatment in substantially the same manner as fabric made entirely of wool.

The heat retractable filaments may be made from synthetic linear polymers other than the polyamides and ester amide interpolymers. Other examples are the polyesters derived from hydroxy acids such as omega-hydroxydecanoic acid, omega-hydroxycaproic acid, or from appropriate derivatives of these acids. Polyesters may also be obtained by reacting dibasic acids and glycols or suitable derivatives of these reactants. As acids may be mentioned carbonic, oxalic, succinic, glutaric, adipic, pimelic, sebacic, hexadecamethylenedicarboxylic, phthalic, etc., and as glycols may be mentioned ethylene glycol, propylene glycol, dimethylene glycol, hexamethylene glycol, decamethylene glycol, etc.

The preferred synthetic linear polymer filaments are, however, those which contain groups of formula NHCO or its sulfur analog as an integral part of the polymer chain. These polymers include the polyamides, the ester-amide interpolymers, the polyurethanes, and their sulfur analogs. Important polyamides in the practice of this invention are those obtained by reacting one or more diamines with one or more dicarboxylic acids or amide-forming derivatives of dibasic acids. On hydrolysis with. hydrochloric acid these polyamides yield a mixture comprising a diamine hydrochloride and a dibasic carboxylic acid. Examples of these polyamides are polytetramethylene sebacamide, polypentamethylene adipamide, polypentamethylene sebacamide, polyhexamethylene suberamide, polyhexamethylene sebacamide, polyoctamethylene sebacamide, polydecamethylene carbamide, polyparaxylylene sebacamide, polyhexamethylene phenylenediacetamide and the polyamide derived from 3,3'-diaminodipropyl ether and adipic acid. The interhydrochloride.

polyamides, e. g. of the general types used in Examples II and VI are especially useful. Another type of polyamides are those obtainable from polymerizable amino acids, as for instance 6- "aminocaproic acid, 9-aminononanoic acid, and

from amide-forming derivatives of these acids, e. g. lactams. 0n hydrolysis with hydrochloric acid these polyamides yield an amino acid, as the The ester-amide interpolymers are obtained by heating a mixture of polyamideforming and polyester-forming compositions, e. g. a mixture of a dibasic acid, a glycol, and a diamine, or a mixture containing an hydroxy acid and an amino acid. The polyurethanes are obtained by reacting a glycol, diphenol, or a dithiol with a diisocyanate or with a diisothiocyanate. Suitable reactants of this kind include decamethylene glycol, resorcinol, or decamethylene dithiol, and decamethylene diisocyanate or. hexamethylene diisothiocyanate.

The above mentioned synthetic filaments are preferably cold drawn, that is permanently elongated by tensile stress, in order to orient them since the oriented filaments have greater strength and elasticity. Furthermore, the riented filaments in many cases, and particularly in the case of the interpolymers retract at temperaturesconsiderably below their softening points and are therefore particularly suitable for making a softfiexible felt. The unoriented or but slightly oriented filaments obtained by spinning under little or no stress, are, however, also useful in the present process.

The various synthetic polymer filaments used to form the felt may be either plasticized or unplasticized. If a softer or lower softening filament is desired it may be plasticized with an aryl sulfonamide such as a toluene sulfonamide or amylbenzene-sulfonamlde. Other plasticizers which may be used are salicylic acid, amylphenol, camphor, dibutyl phthalate and tricresyl phosphate.

The cotton mentioned in Examples I and II may be replaced with various other non-fusible filaments, such as wood, kapok, glass fibers, hair, jute, etc. or even with the higher melting synthetic polymers, e. g. polytetramethylene adipamide or polyhexamethylene adipamide. The proportion of fusible or heat retractable filament used in the mentioned examples as binding agent in the felting composition may be varied from as low as 5 to 10% of the total composition up to 50 or even 75% of the total composition. The time, temperature and pressure used in processes indicated in these examples will vary depending upon the nature of the fusible or heat retractable filament, particularly its softening or retracting point, and on the nature of the other ingredients of the composition. For example, if a high melting filament is used as the binding agent in the felt a relatively higher temperature and pressure will be required than if a low melting filament is used. Likewise, if a soft felt is desired a lower pressure or temperature will be used than if a hard felt is desired. It is not necessary to heat the formed sheet to the melting point of the filament used as the binding agent in the composition. It was quite unexpected to find that heating to a temperature sufiicient to cause retraction of the binding filament, a temperature considerably below its melting point, produced a'felt of good quality. The felting action is facilitated if the heating is done in the presence of water, alcohol or other vapor or liquid which will have a softening effect on the fibers, particularly under pressure.

The felt obtained by this invention can be dyed by usual methods either by application of the dye to the felt or to the fibers separately before being mixed.

The physical properties of the felt such as, for example, its tackiness, feel, etc., may be altered to a considerable extent, if desired, by subjecting the felt to fiufiing and steaming treatments.

When the non-fusible fibers are paper-making fibers, as in Examples 111 to V1, these fibers may be any of the wood pulp fibers such as kraft, sulfite, sulfate, etc., as well as any other cellulosic fiber of similar properties such as bagasse fibers. The proportions of the fusible filament may vary from as low as %10% up to as high as 75 to 85% of the mixture. The conditions of time, temperature and pressure used in preparing the felted sheet will vary depending on the softening point of the particular filaments being used. A higher temperature and pressure for longer times will be required to obtain a satisfactory felt in which a filament having a high melting or retracting point is used in comparison with a filament having a low melting or retracting point.

The pressing treatment in the present process softens the fusible filaments so that they will ad-, here to the non-fusible, or higher fusing, filaments or shrink sufiiciently to bind them into a good felt. The resulting felted sheet may be subjected to steaming or fulling to alter the physical appearance or properties of the sheets if desired.

In the preparation of felt from woven fabrics of wool or other animal fibers mixed with the fusible or heat retractable filaments, as described in Example VII, the proportions of the synthetic polymer filaments may vary over rather wide limits depending on the physical properties desired in the final product. For example, the fabric may be composed of as little as 51-10% or up to as much as 75 or 85% of the synthetic linear superpolymers. A mixture of two or more different superpolymers may be used in preparing this type of fabric.

The denier of the filaments which may be used in any of the different methods described herein will vary depending on the type and appearance of felt desired. For some purposes it is preferable to use binding filaments having a denier of 1 to 3. However. a good felt can be obtained by using filaments having a denier of about 70. If an extremely coarse felt is desired,

even coarser filaments. for example those having a denier of 100 to 150, may be used with satisfactory results. The binding filaments, as in the case of the non-fusible filaments may be straight or crimped.

The felted products of this invention, depending upon the particular filaments and fibers used and upon the conditions of treatment, possess a wide range of properties which adapt the present product for the different purposes for which felt is now used. As examples of some of these uses may be'mentioned the use of soft felt in wadding, slightly harder felt in coat linings and shoe linings, and still harder felt in upholstery, hats and millinery. The felt produced by this invention may be used as filtering agents for gases or liquids and may also be used for insulation purposes, for example, in the insulation of aircraft. It may also be used as a base to which various coating compositions may be applied to form sheet materials of improved properties.

The present invention permits the substitution of cheaper vegetable fibers such as cotton or wood pulp for the expensive animal fibers such as wool or hair now used in the manufacture of felt which results in a considerable saving in the manufacture of felt for use in a large number of purposes. A valuable advantage of the present invention is also found in the fact that the felted products are more suitable for use in those applications where the felt is in contact with organic solvents such as, for example, its use as a filtering agent.

As many apparently widely different embodiments of this invention may be made without departing from the spirit and scope thereof, it is to be understood that I do not limit myself to the specific embodiments thereof except as defined in the appended claims.

I claim:

1. A felted product comprising a sheet of compressed filaments composed of a mixture of fusible staple synthetic linear polymer binding filaments, and staple filame ts which are substantially unaffected at the softening temperature of said polymer, said synthetic linear polymer filaments being heat retracted in situ within the fabric and holding together said last mentioned staple filaments, said synthetic linear polymer filaments being the interpolymerization product of different polymer-forming compositions one of which is composed of a mixture of a diamine and a dlbasic carboxylic acid.

2. The felted product set forth in claim 1 in which one of said polymer-forming compositions is composed of a mixture of hexamethylenediamine and adipic acid.

3. The felted product set forth in claim 1 in which one of said polymer-forming compositions is composed of a mixture of decamethylenediamine and sebacic acid.

4. The felted product set forth in claim 1 in which one of said polymer-forming compositions is caprolactam and another of which is a mixture of hexamethylenediamine and adipic acid.

5. The felted product set forth in claim 1 in which said second mentioned staple filaments are cellulose fibers.

6. A process for preparing felted products which comprises preparing a sheet by matting a mixture of staple synthetic linear polymer filaments which exhibit molecular orientation along the fiber axis and which retract at a temperature substantially below their softening temperature, and staple filaments which are substantially non-fusible and non-retractable at the softening temperature of said polymer, and retracting said synthetic linear polymer filaments by heating said sheet under pressure at a temperature below the melting point of said polymer, said synthetic linear polymer being the interpolymerization product of different polymer-forming compositions one of which is composed of a mixture of dlamine and dibasic carboxylic'acid.

ROBERT WILLIAM MAXWELL.

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2464301 *Dec 18, 1943Mar 15, 1949American Viscose CorpTextile fibrous product
US2476282 *Jan 9, 1945Jul 19, 1949American Viscose CorpTextile products and production thereof
US2476283 *Jan 9, 1945Jul 19, 1949American Viscose CorpTextile products and methods of producing them
US2484787 *Mar 14, 1945Oct 11, 1949Owens Corning Fiberglass CorpBattery separator
US2497117 *Jan 23, 1946Feb 14, 1950Dreyfus CamilleMethod of surface-bonding fibrous batts
US2521985 *Sep 16, 1948Sep 12, 1950American Felt CoProcess of making fibrous units
US2531931 *Jun 1, 1946Nov 28, 1950Arkell Safety Bag CoComposite material
US2550650 *Sep 19, 1945Apr 24, 1951Orlan M ArnoldProcess of producing a plastic composition from waste nylon fibers
US2579036 *Oct 11, 1948Dec 18, 1951Edelman Norman BInsulation, filling, and packing
US2596364 *Sep 9, 1946May 13, 1952Brennan Joseph BMethod of preparing a blank for a conically shaped diaphragm
US2640556 *Jul 25, 1947Jun 2, 1953Brennan Joseph BLoud-speaker diaphragm and mounting
US2646612 *Aug 5, 1947Jul 28, 1953American Viscose CorpLiquid pick-up and transfer means
US2695855 *Nov 23, 1949Nov 30, 1954Gustin Bacon Mfg CoFibrous mat
US2715588 *Dec 16, 1952Aug 16, 1955Du PontLeatherlike products and preparation of same
US2715591 *Dec 16, 1952Aug 16, 1955Du PontSheet material
US2722637 *Feb 3, 1951Nov 1, 1955Brennan Joseph BElectrolytic condensers
US2765247 *Apr 14, 1953Oct 2, 1956Du PontNon-woven sheet material
US2765515 *Oct 7, 1953Oct 9, 1956H & V Specialties Co IncMethod of making a filter for tobacco smoke
US2774128 *Nov 4, 1950Dec 18, 1956Kendall & CoFelt-like products
US2774129 *Nov 6, 1950Dec 18, 1956Kendall & CoSynthetic felts
US2777787 *Nov 15, 1952Jan 15, 1957Gen Tire & Rubber CoFelt sheeting
US2821771 *Apr 5, 1957Feb 4, 1958F C Huyck & SonsMethod of making a papermaker's felt
US2834730 *Jan 18, 1956May 13, 1958Johnson & JohnsonFilter media
US2893105 *Jun 11, 1954Jul 7, 1959Du PontFormation of felt-like products from synthetic filaments
US2905585 *Sep 30, 1954Sep 22, 1959Du PontSelf-bonded paper
US2908064 *Oct 31, 1956Oct 13, 1959Du PontNon-woven filamentary products and process
US2909456 *Jul 27, 1955Oct 20, 1959Du PontNon-woven sheet material
US2910763 *Aug 17, 1955Nov 3, 1959Du PontFelt-like products
US2913512 *May 27, 1955Nov 17, 1959Tudor AbMicro-porous rubber separator for galvanic cells such as accumulators and method of manufacturing such separator
US2920947 *Nov 13, 1956Jan 12, 1960Du PontBristles for abrading surfaces
US2943013 *Jul 27, 1956Jun 28, 1960Hurlbut Paper CompanyHigh ash content absorbent paper for the decorative laminating industry and a process for preparing the same
US2958113 *Feb 21, 1955Nov 1, 1960Du PontNeedled batt
US3016599 *Jun 1, 1954Jan 16, 1962Du PontMicrofiber and staple fiber batt
US3023134 *Jul 15, 1955Feb 27, 1962American Cyanamid CoMolded articles and method of making the same
US3059311 *Dec 16, 1958Oct 23, 1962Du PontStable non-woven batt of polytetrafluoroethylene fibers
US3069017 *Mar 2, 1959Dec 18, 1962Gen Motors CorpDepth type fibrous filter elements
US3093583 *Oct 14, 1958Jun 11, 1963Robert Bosch G M B H FaFilters and processes for manufacturing the same
US3095345 *Mar 22, 1961Jun 25, 1963Riegel Paper CorpProcess for manufacturing paper from synthetic fibers
US3117056 *May 9, 1960Jan 7, 1964Du PontConformable bulkable non-woven web
US3143405 *Nov 3, 1960Aug 4, 1964Owens Corning Fiberglass CorpMethod of producing polyamide coated glass fibers
US3159507 *Apr 22, 1960Dec 1, 1964Comp Generale ElectriciteSeparator for galvanic cells
US3181225 *Apr 8, 1963May 4, 1965Gardner Jr Homer KProcess of resin treating a cotton batting
US3184373 *Jul 5, 1961May 18, 1965Mead CorpFilled paper containing a mixture of resin and mucilaginous material as a retention aid and process for producing said paper
US3186876 *Apr 10, 1962Jun 1, 1965Accumulateurs FixesSeparators for electrolytic cells
US3229008 *Dec 5, 1961Jan 11, 1966Eastman Kodak CoProcess for producing a polypropylene fibrous product bonded with polyethylene
US3272898 *Jun 11, 1965Sep 13, 1966Du PontProcess for producing a nonwoven web
US3307706 *Dec 13, 1963Mar 7, 1967Kendall & CoMilk filters
US3409497 *Feb 21, 1963Nov 5, 1968Minnesota Mining & MfgAdhesive sheet materials and method of making the same
US3855056 *Mar 17, 1970Dec 17, 1974Hitachi Chemical Co LtdProcess for producing synthetic pulp-like materials and producing synthetic papers therefrom
US3920428 *Mar 25, 1974Nov 18, 1975Ethyl CorpFilter element
US4268340 *Mar 7, 1979May 19, 1981Colgate-Palmolive CompanyMethod of forming an absorbent article
US4272264 *Jul 9, 1976Jun 9, 1981Multiform Desiccant Products, Inc.Adsorbent package
US4515854 *Apr 30, 1984May 7, 1985Kuraray Co., Ltd.Entangled fibrous mat having good elasticity and methods for the production thereof
US4565735 *Oct 19, 1984Jan 21, 1986Huyck CorporationPapermakers' felt
US4987664 *Oct 18, 1989Jan 29, 1991The Dow Chemical CompanyProcess for forming an interlocked batting of carbonaceous fibers
US5047453 *May 3, 1985Sep 10, 1991Hoechst AktiengesellschaftProcess for preparing moldings by compacting and simultaneously bonding fibrous material
DE1220141B *Jul 9, 1954Jun 30, 1966Du PontVerfahren zur Herstellung von nichtgewebtem filzaehnlichem Material aus synthetischen Faeden und/oder Fasern
Classifications
U.S. Classification442/324, 55/528, 260/DIG.230, 210/508, 210/504, 28/103, 264/122
International ClassificationD04H1/06, D04H1/54
Cooperative ClassificationY10S260/23, D04H1/06, D04H1/54
European ClassificationD04H1/06, D04H1/54