US 3669823 A
Abstract available in
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Description (OCR text may contain errors)
June 13, 1972 D. E. WOOD 3,669,823
Filed Jan. 4, 1969 I g on 19 INVENTOR.
DENNIS E. wooo I2 l4 I? By FIG. 6
ATTORNEY United States Patent ()lfice 3,669,823 Patented June 13, 1972 3,669,823 NON-WOVEN WEB Dennis E. Wood, Penfield, N.Y., assignor to Curlator Corporation, East Rochester, NY. Filed June 4, 1969, Ser. No. 830,373 Int. Cl. B32b 3/18; D04h 5/00 US. Cl. 161-141 8 Claims ABSTRACT OF THE DISCLOSURE This invention relates to a new article of manufacture, namely, a non-woven web or fabric, and more particularly to a non-woven web made from an isotropic arrangement of fibrous materials containing a plurality of continuous elements having a coating of foam material. Such a web or fabric is particularly suitable for use as an interlining for clothing, and for packing material, upholstery, insulating sound-proofing material, and heating material.
It is known that fibrous materials may be formed into random arrangements and treated, so that they are selfsupporting, by either coating the fibers with binders applied by spraying or by impregnation with solutions of latex, resins, and powders or by assembly of various layers of materials with the addition of prefoam materials, backing cloths, netting and the like.
One object of this invention is to provide a material having greater strength per unit weight and greater resilience, loft, and insulating properties than previous types of random fiber webs.
Another object of this invention is to provide a ma terial which has great tear resistance.
Another object of the invention is to provide such a material in the form of a continuous flexible synthetic resin sheet.
Another object of the invention is to provide a thermal and acoustical insulating material.
Another object of the invention is to provide a material which has embedded within it heating elements.
Further objects will become apparent hereinafter from the specification and from the recital of the appended claims particularly when read in conjunction with the accompanying drawings.
In accordance with this invention the non-woven webs are made of non-matted, uncompressed fibers, which are arranged randomly in three dimensions, namely, in all directions along the length, width, and depth of the web and which have distributed therethrough a plurality of continuous elements which are coated with a film of foam material. The foam material surrounds the continuous elements so that a bond is made between adjacent individual fibers in the region of the crossing points of the fibers and of the continuous elements, while the arrangement of the fibrous materials is maintained without affecting the porosity, resilience and loft of the said non-woven web.
These non-woven webs are manufactured by machines, such as disclosed by my pending patent application Ser. No. 691,544, filed Dec. 18, 1967, now Pat. No. 3,535,187, issued Oct. 20, 1970, which use the air-laid principle, where the fibrous materials and continuous coated elements are collected upon foraminous surfaces aided by suction or reduced pressure. The web having been formed by this preferred method is exposed to treatment effective to foam the coating medium around the continuous elements.
-In the drawings:
FIG. 1 is a cross-sectional view of a small portion of a web made according to one embodiment of this invention;
FIG. 2 is an enlargement of a portion of the web illustrating the three dimensional random arrangement and the interconnection of the fibrous materials to the coated continuous elements;
FIG. 3 is a cross-sectional view of another embodiment of this invention showing weft and warp strands;
FIG. 4 is a perspective view of another embodiment showing arranged warp strands;
FIG. 5 is a cross-sectional veiw illustrating two sheets of flexible synthetic resin having between them a nonwoven web made in accordance with this invention;
FIG. 6 is a cross-sectional view, similar to FIG. 5, illustrating a web employa-ble for acoustic purposes;
FIG. 7 is a cross-sectional View, similar to FIGS. 5 and 6, illustrating a heating pad made according to this invention;
FIG. 8 is a similar cross-sectional view, illustrating a still further embodiment of the invention, suitable for use as a garment interlining or as a filler;
FIG. 9 is a similar view illustrating a still further modification of the invention;
FIG. 10 is a sectional view illustrating a still further modification of the invention;
FIG. 11 is a sectional view illustrating still another embodiment of the invention; and
FIG. 12 is a sectional view illustrating a still further embodiment of the invention.
In FIGS. 1 and 2, 10 denotes an isotropic non-woven web made up of fibers 11 and continuous elements 12. The continuous elements are coated with foam 14.
The fibers preferably are curled or crimped but straight fibers of the same type or of different types may be used. The fibers may be natural, synthetic, vegetable, animal, or mineral. Any of these fibers may be used alone or mixed with each other.
The fibers 11 are preferably of various lengths, from about one-half inch to two inches, although shorter and longer fibers may be used, and they are intermingled in random arrangement so that they lay at various angles, both horizontally and vertically, to form a three-dimensioned web with the individual fibers contacting the foam coated continuous elements 12 (which also may be of various materials and embedded haphazardly through the web)- at separate points of contact throughout the web. Relatively few pairs of individual fibers contact one another at more than one point, and each continuous element of the web contacts a plurality of fibers at spaced points which may be in the same or in different planes.
The continuous elements are coated with the foam material 14 so that the foam completely covers their outer surface. The amount of foam is sufiicient for the end product needs to impart internal resilience and to bind the individual fibers so that they adhere to the coated continuous elements and have transversely extending fibers from their points of contact as detailed in FIG. 4. No spaces between the individual fibers and continuous elements are substantially free of the foam material to maintain the softness and insulating properties of the web. Apart from the incidental bonding of the fibrous material with the foam coating of the continuous elements the individual fibers remain unbonded and hence retain their natural springiness and impart to the web further resilience and loft.
The spaced joining of the individual fibers to the coated continuous elements, forming the three-dimensional, random arrangement, prevents matting and reorientation of the fibers due to externally applied forces.
The individual fibers may be of one type or a combination of types, for example: cotton, silk, wool, hogs hair, sisal, and synthetic or man-made fibers such as the cellulosic fibers, notably viscose or regenerated cellulose fibers, cellulose ester fibers such as cellulose acetate and cellulose triacetate; the polyamide family of fibers such as nylon 6, nylon 66, and nylon 610; protein fibers such as Vicara, halogenated hydro carbon fibers such as Teflon (polytetraifludroethylene); hydrocarbon fibers such as polyethylene, polypropylene, and polyisobutylene, polyester fibers, vinyl fibers, and acrylic fibers, mineral fibers such as: glass, aluminum oxide, graphite, silicone carbide, silicone nitride, and tantalum carbide, boronitride, etc., thermoplastic or thermosetting extrusions: such as polymeric amides, vinylidene chloride, quartz, acetone solutions, protein base minerals, and petroleum derivatives.
The continuous elements may be inthe form of filaments, bundles of aligned fibers, threads, yarns, cords, wires, and the like. The coat of foam material may be a synthetic rubber type, an ethylene, urethane, styrene, or plastic resin; in fact any material or dispersion which has foam characteristics. Materials which are mixed immediately before application and foam at ordinary temperatures or heat activated foams may also be used.
Typical organic foaming agents, which can be used include inexpensive chemicals, such as ammonium carbonate, through which air or steam is passed, and which decompose into gases, diazo compounds which generate nitrogen, and organic acid terminal groups which in the case of the isocyanates liberate carbon dioxide.
Some nitrogen generating foaming agents include diazoaminobenzene, dinitrosopentamethylene tetramine, the tin and zinc chloride salts of diazotized p-aminoethyl, benzylaniline, the zinc chloride salt of p-diazo diphenyl amine, the zinc chloride salt of diazotized 4-aminodiethyl aniline. The aforementioned materials can be activated by means of ultraviolet light.
Other foams which may be used include polyurethane foams, sponge rubber, and vinyl foams.
In the figures for ease in illustration, the coated filaments are shown with the coating broken away near the ends of the elements; and the relative proportions of the coated filaments and of the coating are exaggerated.
A quantity of foaming agent is required adequate to give at least an amount of gas evolution equal to at least three times the volume of the adhesive. An amount of foaming agent in the order of A to of the adhesive is satisfactory, although up to 30% can be used.
Polyurethane foams suitable for use in my invention may be prepared in the usual manner by reacting a polyester, diisocyanate and a water-bearing activator. Foams of this type are very economical, foam in situ and offer excellent adhesion. They also require little or no heat for curing since the reaction is exothermic. There are a few disadvantages encountered while using these foams. For example, the diisocyanate is semi-toxic and requires safety precautions. Moreover, the density of the foam is varied by very slight changes in the recipes used. Hence, a great deal of care must be used in the mixing control of the foam. In order to obtain elastomeric polyurethanes, between fifteen and forty parts of diisocyanate must be used with one hundred parts of polyester. Polyesters suitable for reaction with diisocyanate include lineal polyesters terminating in hydroxyl groups and having a moderate molecular weight.
Vinyl resins incorporating a foaming agent may also be used in my invention. The continuous yarns may also be coated with vinyl dispersions containing a foaming agent and the foam allowed to expand. While vinyl foam requires no application of pressure, it does require curing at 330 F. Some vinyl resins, which may be used for this purpose, include polyvinyl chloride and polyvinylidene chloride.
Plasticized polyvinyl chloride having a cellular structure is also a good coating medium for the continuous elements provided it is in the form of a plastisol. Plastisol here refers to undissolved vinyl chloride polymer in powder from dispersed in a liquid plasticized. For every parts by weight of polyvinyl chloride the plastisol includes approximately 20 to 200 and preferably 60 to parts by weight of plasticized and approximately from 3 to 25 parts by weight of blowing agent. Small amounts of thermal stabilizer and color pigment may be added to the plastisol.
The choice of plasticizer and plowing agent is not critical. Di(Z-ethyl-hexyl)phthalate, dioctyl phthalate, tridecyl phosphate, dibutoxyethylphthalate, dibutyl phthalate, methoxyethyl acetyl vicinaleate, sebacic acid esters such as dibutyl sebacate and dibutoxyethyl sebacate, epoxidized soy-bean oil, di(2-ethy1-hexyl) azelate, didecyl adipate, diisooctyl adipate, butyl isodecyl phthalate, isoctyl palmitate, octyldecyl phthalate, didecylphthalate, isooctyl isodecyl phthalate, dioctyl sebacate, triethylene-glycol dipel arganate and combinations thereof are among other suitable plasticizers.
Examples blowing agents are N,N-dimethyl-N,N-dini troso terephthalamide, N,N-dinltroso urethanes, benzilmonohydro zons, a,oU-azobisisobutyronitrile, diazoaminobenzene, 1,3-bis (O-xenyl) triazene, 1,3-bis (p-xenyl) triazene, sodium bicarbonate and oleic acid, ammonium carbonates, and mixtures of ammonium chloride and sodium nitrite.
Compounds which act as thermal stabilizers include, for example, barium, and cadmium salts of long chain fatty acids such as lauric, capric, caprylic, oleic, myristic, palmitic, and stearic acids, tetrasodium phosphate of Group II metals, alkaline earth ricinoleates and antimony zinc, sodium and cadmium arsenates and arsenites.
FIG. 3 shows a web 20 in which the fibers 11 are laid down in random fashion in three dimensions throughout the length, width, and depth of the web, but in which the continuous filaments are arranged in the form of weft and warp strands 12 and 12 respectively.
FIG. 4 shows a web 25 in which the fibers 11 are again arranged in random fashion lengthwise, widthwise, and depthwise of the web, but in which the continuous filaments 12" are all arranged as warp strands.
The isotropic non-woven webs may be made of any desired thickness, for example from /s" to 2" or more. When the web is of about thickness or less the foam coated continuous elements may be positioned so that the foam will penetrate the surface of the web thus giving a novel effect.
Some examples of webs made according to this invention are described below. These examples are given as illustrative embodiments and should not be construed as limitative.
. EXAMPLE 1 As shown in FIG. 5 a sheet covered non-woven web 15 may be made from organic synthetic resinous material, as the upper and lower surfaces 16 and 17, and elastomeric foam covered multifilament yarn 12', as the con tinuous element forming the grid, and a synthetic fibrous material 11' which acts as the fiber matrix.
The matrix is formed preferably according to the method disclosed in my pending application Ser. No. 691,544, above-mentioned using a blend of synthetic fibrous materials of which 70% is polyester and 30% Orlon. The multifilament yarn is coated with a plasticized polyvinyl chloride and embedded within the matrix in a random arrangement to form an isotropic reinforced nonwoven web. The web so made is conveyed to a heated chamber where the heat decomposes the blowing agent and dissolves the polyvinyl chloride in the plasticizer, thus forming a continuous cellular structure around the continuous yarns 12', and the individual fibers adhere to these cellular yarns giving the required three-dimensional strength. The heating can be done by transporting the web through an oven heated to a temperature between 300 and 450 F. and preferably approximately 340 to 400 F. for about to 12 minutes. The time and temperature needed will vary with the materials used.
While the web is cooling a coat of adhesive is applied to the topsurface of the web. A suitable adhesive may be prepared from 100 parts of synthetic butyl rubber and 33 parts of a mixture of chlorinated biphenyl and monochlorobiphenyl (Aroclar 5460). Attached to this adhesive face is a sheet 16 of transparent flexible polyester synthetic resin such as sold commercially as Mylar. The underside of the web is also coated with the aforementioned adhesive and another sheet material 17 similar to the polyester resin, or another synthetic resin adapted to contributeother properties such as feel and so forth, is applied thereto. The organic synthetic material may be for example one of the following: polyethylene, plasticized or unplasticized, polyvinyl chloride, or polyvinyl acetate and the like, polytetrafluoroethylene, chlorosulphonated polyethylene or other halogenated polyethylenes, polyamides, cellulose acetate, or ethyl cellulose.
' An elastomeric foam is preferred because of its excellent crease resistance, flexibility, pliability, and softness. Thermoset resins after being creased or folded have a tendency to always crease in the same place, and after continual folding the thermoset resin tends to crack which proves to be unsatisfactory.
It is possible to provide decorative effects by adding coloring matter to the foam-material or to the adhesive, or of courseusing various textures and colors to the sheeting or by'printing. The product so produced has an unusually great resistance to tearing and gives a good lofty, uncompressible material.
Example 2 Where acoustical properties are desired solid particles 19 are added 'to the fiber blend. These particles have a specific gravity higher than that of the fibers, are of nonuniform size, are deposited on the Web surface and are incorporated within the web structure. Plastic film is then added to the outside surfaces similar to Example 1 above. The material is then subjected to treatment such as combined pressure and heat, to produce surface irregularities. When the so treated material is impinged on by sound vibrations, the encapsulated particles suspended throughout the material and incorporated in the cellular structure around the continuous elements will set up vibrating foci and because of the variation of the amplitude between these particles, the sound energy conducted from the plastic film surface, which also encumbers the sound waves, is dissipated within the structure. Particles having a specific gravity above 2.5 have proven effective but provided the specific gravity is considerably higher than that of the fibrous materials effective sound hysteresis is obtained. The particles should be non-uniform in weight and size, which should vary between 20 and 500 mesh. These materials may be zinc, tin, lead, various steel grits, shot, brass dust, etc.
EXAMPLE 3 A non-woven matrix 21 ,(FIG. 7) is constructed using fibrous materials which have relatively high heat resistance properties such as polyester with the trademarks Vycron, Kodel, Fortel which have melting points above 485 F. or acrylic and acetate fibers or Du Ponts nylon with the trademark Nomex. Into such a matrix polyurethane foam coated electrical heating wires 22 or conductive metallic random webs are embedded in a predetermined pattern into the center zone so that the total resistance of the embedded wire, when electrical current is applied, produces heat but not to the degree where burning or decomposition of the fibrous materials or foam takes place. The composite so produced is cut to the required lengths and the final electrical connections are made after which the composite material may be finished with most known products provided these do not interfere with the internally insulated heating wires. These finishes may be cotton or rayon coverings, edge bindings of various types, spray bonding, etc.
EXAMPLE 4 This non-woven web 30 (FIG. 8) is made by the preferred method to produce a truly isotropic matrix so that one zone 31 is made of 70% of the total matrix 'weight of acrylic fiber while the other outer zone 32 comprises a blend of 20% wool and 10% rayon fiber. The fibers are preferably crimped and of various lengths from about /2" to 2.". Into the center of this matrix a continuous high tenacity 500 denier polyester yarn 35 coated with polyvinyl chloride plastisol 34 is introduced so that the coated yarn is positioned in longitudinal lines spaced 1%" apart across the web and in three layers 36, 37, 38 in depth, there being 96 strands in all for a 40 wide material and with a depth of 1 /2". 0
The fibrous materials are intermingled in a random arrangement so that they lay at various angles in both horizontal and vertical planes to form a three-dimensional web with the individual fibers contacting the coated continuous yarns at their separate points of contact throughout the web, there being individual fibers extending from these continuous coated yarns at a plurality of spaced points throughout length, width and depth. Also, the individual fibers extend transversely throughout the depth of the web to the opposite upper and lower surfaces thereof, thereby tying the web into an integral structure so that the non-woven web is self-sustaining and has considerable strength in its lateral, longitudinal and transverse directions. It can be handled without the addition of any backing material and is capable of retaining stitches so that the web may be stitched to woven fabrics to form a laminated fabric. The web also is an excellent air retainer and the insulation value thereof is very high. Because of the random three-dimensional arrangement of the fibrous materials, and the cellular structure of the foam material, there are innumerable intercomrnunicating voids in the web so that air may pass through the structure at a relatively slow rate.
The polyvinyl chloride plastisol was prepared from the following constituents:
Parts by weight Polyvinyl chloride such as Geon 121 100 Plasticizer: 1
Epoxidized soy-bean oil (Paraplex G-62) 50 Di(2-ethyl hexyl) phthalate 50 Blowing agent:
Oil-soluble petroleum sulfonate 3 N,N'-dimethyl-N,N-dinitrosolenephthalamide l Pigment 10 Ground wood cellulose filler 10 After treatment by heat the blowing agent is activated within the plastisol coating around the continuous yarns, permanently locking the individual fibers extending from the cellular structures in all directions so that a cross-section of the web formed appears as a series of individual fiber bridges in all directions and planes, from one surface to. the other and from one continuous yarn to adjacent yarns. The use of fibers of different lengths provides a better fiber distribution throughout the webs and also provides more points of bonding.
The strength, resilience and loft retaining qualities of the web are due to the random arrangement of the fibers, the continuous yarns, and the thin elastic foam coating which fastens the fibers together at the points of contact with the foam coated yarns. The vast number of voids or air spaces in the web imparts thereto such a high degree of porosity that the web breathes and therefore it can be used advantageously as an interlining for garments or as an air filter or where the cushioning properties may be used.
EXAMPLE This non-woven web 40 (FIG. 9) was made by the preferred method to produce a truly isotropic zoned matrix, so that one outer zone 41 is constructed of 30 denier Kodel fibers of between and 1 /2" staple length. The other outer zone 42 was made of Vinyon H.H. a copolymer of vinylchloride and vinyl acetate of short staple length. The inner zone 43 was so constructed that continuous monofilaments of spandex fiber 45 of 50 denier heavily coated with a polyvinyl chloride plastisol 46 are positioned .in longitudinal lines spaced A apart across the web one layer deep.
The fibrous materials are intermingled isotropically each side of the coated monofilaments with a percentage of fibers interconnecting the two outer zones through the 32nd inch gaps to provide an integral matrix.
The matrix is subjected to heat treatment so that the plastisol coating around the continuous monofilaments is foamed by activating the blowing agent thus causing the inner zone to become a foam sheet, reinforced with the monofilaments and at the same time bonding the two outer zones together.
By adjusting the heat requirements during the blowing agent cycle it is possible to melt the lower temperature vinyon fibers to obtain a semi-rigid sheet so that the finished composite has a high loft top layer with an inner core of foam reinforced with continuous elements and a bottom surface of a semi-rigid structure completely integral to one another.
EXAMPLE 6 A non-woven web 50 (FIG. was produced using a blend of 60% 1 /2 denier glass fiber 51 and 40% denier nylon 52 to form a matrix of 10 oz. per sq. yd. Into this matrix a series of nylon monofilament strands 53 coated with mixture of polyisocyanate and alkyd 54 was introduced, to produce a cellular structure with the filaments divided into two groups, each consisting of a line of closely spaced strands. In one of the lines the filaments were deposited in an irregular array 56 generally in the direction of movement of the matrix; and in the other line these filaments were moved back and forth across the matrix bridge point, so that the second group of filaments 55 were deposited generally crosswise over the first group, so that both groups are substantially in a random fashion but in different planes within the depth of the web. The composition so formed, with the fibrous isotropic matrix and the continuous cellular coated monofilaments, gives a high strength, loft, and porosity not heretofore obtained in non-Woven laminates, while retaining the properties and characteristics of the bonding of the fibers to the cellular coating of the monofilaments which is the prime function of my invention.
EXAMPLE 7 A non-woven composite 60 (FIG. 11) is manufactured in accordance with this invention by vertical 61 and horizontal 62 deposition of coated continuous elements 64 within a matrix 63 of the staple fibers and combining the two constituents into one integrated structure.
The materials used in this example were a 1" staple polypropylene fiber in various deniers within the range of 10 to 20 and a 200 denier continuous filament of nylon 6. The polypropylene fiber was processed through the outer chambers of the machine of application Ser. No. 691,544 to a web weight of 2 oz./sq. yd. per chamber while simultaneously the continuous filaments were coated with polyvinyl chloride plastisol of a similar composition to that of Example 4 and arranged such that there are eight filaments per linear inch of machine width which are processed through the center section of the said machine.
The fibers and coated filaments are intermingled in the condensing chamber air stream and deposited upon the pair of condensing cylinders which are set such'that the distance between these suction rolls or condensing cylinders corresponds approximately to the desired thickness of the finished web, in this case 1%". The fibers and filaments are carried in the current of gas the width of the machine and deposited upon the suction rolls in such a manner that the fibers and filaments build up into the roller gap and over its entire width. Due to the turbulence of the air stream the coated filaments begin to swing and oscillate back and forth in the area fronting the condensing cylinders. They are therefore seized in irregular order sometimes by one suction roll, sometimes by the other. As they advance between the rollers they are embedded within the staple fibers. Since the rate of delivery of the continuous coated filaments is a multiple of the rate at which the matrix is formed, a short length of an individual filament is drawn to one side of the condenser suction area, and due to the oscillation of the air stream carrying the fibers and filaments, an adjacent part of the same filament is seized in the next moment by the opposite suction roll and thus the filament is disposed in a horizontal orientation within the staple fiber structure. Since the air stream oscillates not only back and forth but also from side to side, in the next moment another continuous filament is laid crosswise at a random angle to the previously deposited filament. This process is repeated in rapid succession over the entire fiber forming apparatus such that a random homogeneous fiber structure is produced between the staple fiber and continuous foam coated filaments in length, width, and depth. Thus a plurality of polyvinyl chloride plastisol coated continuous filaments are advanced along a path between spaced web forming condenser cylinders so that the filaments move adjacent and on to the said cylinders when at the same time an isotropic matrix of staple fiber is being formed. The gas streams within the condensing chamber are passed in a direction extending transversely to the continuous elements; and the gas streams have a component horizontally to the fiber and filament flow path so that movement of the filaments as they pass between the matrix forming cylinders is disrupted and individual filaments are caused to be dispersed in a side to side and back and forth random array within the staple fiber structure.
By heat treatment the blowing agent is activated within the plastisol coating around the continuous filaments permanentlylocking the individual staple fibers extending from the cellular structures in all directions and planes throughout the web. The wave formation of the cellular coated continuousfilaments forms a random bridge construction from one surface to the other imparting strength,'resilience andloft and a high degree of porosity to the non-woven web. i
EXAMPLE 8 In a further example, a non-woven web 70 (FIG. 12) is formed in a similar manner to that of Example 7. The matrix 70 is built up by a continuous element 71 which is in the form of a fiat acetate filament the equivalent of a 100 denier fiber with the brand name Seratelle produced by British Celanese Ltd. and is foam coated with a polyurethane foam 73 prepared from polyester, diisocyanate and a water bearing activator. The other constituent 72 is a 20 denier staple length acrylic fiber with a residual shrinkage of 17% when exposed to heat at 80 C. for minutes. This shrinkage fiber is processed through the outside chambers of the aforementioned machine to a weight of 1 oz./ sq. yd. per chamber.
The web forming condenser cylinders are set at a distance of 3" so that when the composite matrix is built up, the staple fiber 72 forms substantially at the outside surfaces while the continuous elements 71 are deposited in the aforementioned wave formation giving a continuous bridge structure between the outer fibrous surfaces. Upon exposure to heat of 80 C. for 5 minutes the foam material around the .continuous filaments expands to a cellular structure and at the same time the shrinkable fibers buckle, curl and loop imparting bulk to the outer surfaces while being locked to the cured cellular structure of the inner component. Thus the non-woven web so formed has an outer surface of high bulk staple fiber while the inner core is made of cellular reinforced structure bonding the outer surfaces into an integral matrix of novel characteristics of texture, porosity and bulky softness.
When forming a composite of shrinkable fibers and a foam material, the two or more heat activated materials should be so designed that the temperature of exposure will activate both components at the same time and temperature.
Articles manufactured in accordance with this invention are free of one of the great difiiculties encountered in the manufacture of normal non-Wovens where bonded by the impregnation process. In this process the speed of production and acceptability of the product are controlled to a large extent by delamination. Fine denier fibers of short staple length tend to mat together so that during drying the excess moisture moves slowly to the outer surface causing delamination. With a coarse springy fiber, the heating method, normally hot air, can freely percolate through the web which assists the speed of drying and there is less tendency to delaminate. However, whatever the fiber, some delamination will occur at production speeds and economical drying oven lengths. Articles of equal characteristics may be made by this invention though, at high production speeds and without delamination caused by migration of binder solids during drying.
The non-woven constructed in accordance with this invention comprises a truly isotropic arrangement of fibrous materials which are non-matted, uncompressed, and either straight, curled or crimped of various lengths from about /2" to 2" and are blended in such a way that a preponderance of one type of fibrous material may be arranged on one surface or various blends of fibrous materials may be blended throughout the nonwoven web so that they intermingled in random arrangement and lie at various angles, both horizontally and vertically. Relatively few pairs .of individual fibers contact at more than one point; and each fiber contacts a plurality of other continuous elements at spaced points which may be in the same or different planes, there also being individual fibers extending transversely throughout the depth of the web to opposite upper and lower surfaces, thereby tying the web into an integral structure from upper to lower surfaces.
Having thus described my invention, what I claim is:
1. A fibrous web having staple fibers arranged in random fashion in three dimensions along the length, width and depth of the web, some of the fibers extending through the depth of the web,
said web including a plurality of elements, different from said fibers, and each of greater length than said fibers and each coated with a film of foam, said web being bonded together only by the bonds made between adjacent fibers and the foam at the crossing points of said elements and the fibers, and said fibers being otherwise free of foam, whereby the web is bonded into an integral structure while maintaining the random arrangement of the fibers Without affecting the porosity, resilience, and loft of the web.
2. A fibrous web as claimed in claim 1, wherein the fibrous structure is formed of a plurality of zones comprising, respectively, diiferent materials, individual fibers extending from one zone to another, and some individual fibers extending transversely throughout the depth of the web to the upper and lower surfaces thereof, thereby tying the web into an integral structure.
3. A fibrous web as claimed in claim 1, wherein said elements are filaments coated with a film which contains an aqueous dispersion of a chemical material, a plasticizer and a blowing agent, so that when the web is exposed to heat, the blowing agent is decomposed and the coating material attains cellular structure.
4. A fibrous web as claimed in claim 1, wherein said elements are filaments coated with a cellular binder which has a weight from 1 to about 9 times the weight of an element.
5. A fibrous web having staples fibers arranged in random fashion in three dimensions along the length, width and depth of the web, and including a plurality of filaments, some of which extend throughout the depth of the web from top to bottom thereof, and which are of greater length than said fibers and are coated with a film of foam which surrounds these filaments so that a bond is made between the fibers and said filaments only at the crossing points of said filaments and the fibers, and said fibers being otherwise free of foam, thereby bonding the web into an integral structure while maintaining the random arrangement of the fibers Without affecting the porosity, resilience and loft of the web.
6. A fibrous web as claimed in claim 5, wherein solid particles are incorporated Within the web structure to give the web acoustic properties.
7. A fibrous web as claimed in claim 1, wherein apart from the bonding of the fibrous material with the foam coating of the continuous elements, the individual fibers remain unbonded, but no spaces between the individual fibers and the continuous elements are free of foam.
8. A fibrous web comprising a zone at one side of the web which comprises synthetic fibers arranged in random fashion lengthwise, widthwise and depthwise of the web,
a zone at the other side of the web comprising a mixture of natural and synthetic fibers arranged in random fashion, lengthwise, widthwise, and depthwise of the web, and
a zone intermediate the other two zones and comprising elements different from said fibers and each of greater length than said fibers and each coated with a foam material, with individual fibers of the 1 1 first two zones contacting theeoated'elements at their crossing points, I some fibers extending transversely throughout the. web to the upper and lower surfaces thereof, thereby tying the web into an integral structure. .1
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