[1]U-nited States Patent Office 3@350,486 3,350,486 METHOD OF PRODUCING CONTOUR MOLDED COTTON BATTING Nestor B. Knoepfler, New Orleaiis and Homer K. Gardner, Jr., and Henry L. E. Vix, gletairie, La., assignors to the United States of America as represented by the Secretary of Agriculture Ffled Apr. 29, 1965, Ser. No. 452,032 11 Claims. (Cf. 264-112) A non-excl-usive, irrevocable, royalty-free license in the invention herein described, throughout the world for all purposes of the United States Government, wilh the power to arant sublicenses for such purposes, is hereby granted to the Govemment of the United States of America. This is a continuation-in-part of Ser. No. 271,525, which wasfiled Apr. 8, 1963 and which has now matured into Patent No. 3,181,225, granted May 4, 1965. The invention described therein is here supplemented by unexpected and si.-Ilificant data which was obtained in the continuation of our investigations. We now have discovered contoured and/or compaicted batts can be prepared by slight modification of the process disclosed in said Patent No. 3,181,225. We have unexpectedly found that by modifying the process of said Patent No. 3,181,225, we can (1) produce a batt which has a permanently-contoured shape, (2) produce a batt which has preselected and desired varying degrees of compaction, either in the same or in separate ,batts, and (3) produce a batt which has the combined desirable qualities of permanently-contoured shape aiid permanently-compacted homologous or varying configuration. To obtain the most desirable batts with contoured confi,-uration and/or varyin.- degrees of compaction, we can submit the cellulosic batting material to the resinous spray treatment of said Patent No. 3,181,225; and when the spray damp wet add-on is about from 50% to 150@%, we place the spray damp material in a confinin.- mold which has the desired curved configuration and/or varying compactness, and cure the material while holding it in the suitable configuration. This in general is the process of our new invention. The flaished batts by process of this invention can have the same dimensional stability described in said Patent No. 3,181,225, the coherence, and the resiliency, etc. However, while the material produced by process of said Patent No. 3,181,225 is generally of a homogenous and re,-ular flat configuration, the material produced by the process of this continuation-inpart can have a curved configuration, a varying de,-ree of compactness, or a combination of these. For producing the contoured or the variably compacted batts by processes of this invention, it is essential that the degree of dampness amounts to at least 50% by weight based on the weight of the unsprayed web. We have found that a spray dampness under 50% will yield a batt with poor resilience and poor shape-retention. The material will not hold the predetermined configuration or degree of compaction. A spray dampness above 150% will yield a batt with a skinning effect, and will be overly stiff and may be brittle. T@he hand of this material will be undesirable and rough. The undesirable qualities are generally attributable to resin migration during dryin,-. The preferred 100% spray dampness to be in the "preferred" category must be from a 20% solids bath. This invention relates to a process for improvin.a fibrous cotton batt as its dimensional stability, resilience, and compaction are improved. The process consists basically of the application of chemical substances to the opened and garnetted fibers of cotton, which can consist of a blend of various grades of cotton lint and linters Patented Oct. 31, 1967 2 to produce a superior batt with excellent variable properties. This invention is a product of investigative effort to combat the increasing competition to cotton material by the recent advances of the natural and synthetic foamed products, which are dimensionally stable, and which have significantly better coherence and resiliency than batting made from untreated cotton fibers or other such cellulosic materials. 10 The main object of this invention is to provide a process of the manufacture of fibrous batt with dimensional stability and improved @resiliency under varying conditions of hurnidity and use. The utility of the improved batting lies in the fact that the more economical material 15 which the batting industry has been providing in the past can regain its markets lost to the synthetics and others by simple chemical processing of the low--,rade cofton materials, These have for years been employed in the furniture and automotive industries for such articles as 20 matt@resses, upholstering of many furniture pieces, automotive cushioning, etc. Another object of this invention is to provide a process for @making fibrous batt with improved resistance to compaction, and having better coherence than normal com25 mercial batting. A further object of this invention is to facilitate the production of an improved batt, which will retain its dimensions, and will resist compaction or settling in specific applications such as insulation. 30 The application of the ohemical s@ubstances is done through a single or a plurality of nozzles, which wet the web as it moves past the fine spray. The spray must be controlled as to avoid extremes in wetting the web. The application of a fine mist or a fog would dissipate the 35 chemicals to the air or cause the chemicals to permeate through the fibrous structure without adherin.- to any surface, thereby wasting the chemicals, while a heavy spray would cause overwetting in that large droplets would lodge irregularly or nonuni.'Lorinly throug-hout the 10 structure of the web. The economic feasibility of the products of our invention depend to a considerable extent upon the rnethod of application of the chemicals. The chemicals employed here are form-ulations in which a crosslinking or reactive 45 type resin can be used either alone or in combination with a film-forming latex. Performance depends on the proper selection of resin and latex, and the uniforin distribution of the resinous substances within the physical structure of the web. The deposition of chemicals may 50 occur on the surface, as a physical occlu@ion which bonds the fibers of the loose structure, or as a chemical reaction which might take place either on the surface or within the cellulosic molecular structure of the cotton fiber. A crosslinking reaction gives the cellulosic mole55 cule a certain amount of rigidity, which in turn causes physical, as well as chemical, rigidity or resiliency-as desired-to the cotton batt. The resins used in this process are selected for their inherent properties, which include the capability of react60 ing chemically with the cellulose of t-he cotton. These resins by virtue of the reaction with the cellulose molecules, by crosslinking or other phenomenon, enhance the resilience of the fibers, or improve their resistance to per-manent deformation resulting from flexing or bending. 65 The function of the latex, which in effect is a film forming resin, or coating, i@ to assure interfiber binding at points of contact between -fibers. The latex then contributes to dimensional stability, coherence, and textile tensile and tear strength of the finished batt. The application of a latex to the web yields a batt 70 with improved tearing strength, dimensional stability, and resistance to compaction through physical shiftin.- of
[2]8,350,486 3 lbers within the structure under varyin.- conditions of-@iumidity. The application of both crosslinking resin and latex to the web will yield a batt with these characterstics plus improved resiliency. An important feature of this invention is the means employed for the application of the chemical substances to the webs, or layers of fibers, so that a great degree of uniformity of treatment can be obtained while the operation is of a continuous economic character. The advantages and objectives become more apparent upon a consideration of the accompanying sr-hematic drawing in which FIGURE 1A depicts an embodiment of a conventional apparatus for carrying out the inventive processin.- sequence for the production of batting, including the conventional method of crosslapping and the application of an appropriate resin alone or combined with a latex by spraying; FIGURE IB depicts another embodiment of apparatus similar to that of FIGURE 1A, differing therefrom in the main in that it illustrates the ronventional reel-type batt former; FIGURE 2 shows a sectional view of a batt prepared by adherence to the process of this invention; FIGURE 3 shows a cross section of a batt after spraying, and during drying, while said batt is restrained between frames spaced to regulate the density of the product; FIGURES 4A, 4B, and 4C are views depicting the use of expanded metal for mold parts to produce a batt simulating the contour of the arm of ati upholstered sofa; FIGURES 5A, 5B, and 5C are views depicting the use of expanded metal for mold parts to produce a batt simulating the contour (yf an automobile bucket seat; and FIGURE 6 is a view illustrating that in the molded product the greatest density occurs at the thinnest portions of the batt. Referring to FIGURE 1A, blended cotton fibers consisting of textile wastes and linters in various proportions are fed to the main cylinder la of the carding section of a conventional -arnett, worked by worker rolls 2a, stripped from the worker rolls and returned to the main cylinder by stripper rolls 3a, removed from the main cylin&r by conventional doffer roll 4a, combed from the doffer roll by comb 5a which works against the doffer roll 4a and baffle 6a, and transported in web form on traveling aprons 7 and 7a for lap-forming operations. In FIGURE 1B, the apparatus depicted operates in much the same manner as that of FIGURE IA, with the parts thereof corresponding to those of FIGURE 1A being respectively illustrated by main cylinder lb, worker rolls 2b, stripper rolls 3b, doffer roll 4b, comb 5b, baffle 6b, and apron 7b. This embodiment ditters in the main from that of FIGURE IA in that the web form is transported to reel 11 for lap-forming operations. The foregoing description relating to FIGURES 1A and 1B constitutes conventional commercial practice and as such is incidental to and forms no part of the instant invention. Followin-, removal of the web of carded cotton fibers frorn the main cylinder, the web is sprayed by means of spray device ga in FIGURE IA or Sb in FIGURE IB, and the sprayed web 9a in FIGURE IA or 9b in FIGURE IB, iiow wetted with the several component rea,@ent according to the instant invention, is lapped to produce partiallyformed batt 10 as shown in FIGURE 1A or collected on reel 11 as shown in FIGURE IB. The sprayed and layered webs are then condensed into batts through rolls or other suitable pressure means, not shown, to assure good contact betwe-,n the successive layers 12 (FIGURE 2) of webs. In FIGURES IA and IB, thefeed material consists of a blend of 60% of first-cut linters, and 40% of various grades of textile wastes. This mixture is an example, and in no way critical to the process. The blend is passed through suitable commercially-available processin.a units 4 to be formed into a web or layer of fibers, which are discharged onto a moving belt or conveyor. At this point, the fibers are in an extremely open configuration, which makes possible the application of the resins and/or resinous or other type latex by a spray system, using a single or a multiplicity of spray heads or nozzles in such a way as to achieve a uniform distribution of the chemicals on the web. The wet add-on of the solutions can be controlled to between 20 and 150% of the weight of the fiber 10 feed by controlling the flow of solutions to the spray heads. In specific examples of this invention, the opt,.mum wet add-on varied from 70 to 120%, depending on the, properties desired in the finished products. 15 The concentration of the spray solution or suspension mixture can vary from 1 to 35% by wei.-ht total solids,, dependin- on the resin to latex ratio, the nature of the reagents, and the properties &sired in the finished prodtict. After being sprayed, the web or layer of fibers is 20 either crosslapped conventionally as in FIGURE IA, and then condensed through suitable rolls or other means to@ assure good contact between successive layers or webs,. or collected on a reel, where condensin- is done on a layer for layer basis, as shown in FIGURE 1B. The 25 formed batts are then constricted by frames 13 (FIGURE 3) in such a manner as to maintain a specific height during drying and curing; or dried and cured without restraint, depending on the desired physical properties, such as density. Since a structure consisting of cellulosic fibers 30 which have been formed into batts tends to expand in volume when subjected to heat or hot air circulation, this invention takes adavntage of this inherent characteristic in order to achieve a more open (less dense) finished product. The density of the product therefore can be 35 varied by either varying the weight of the webs, the number of webs or layers of fibers used in the batt, or by varying the spacing between frames, as in FIGURE 3, or by adjusting the spacing between suitable open mesh dual belts for continuous drying. 40 The spray from a single solution has been accomplished by investigative formulation, which included the search for compatible systems which can contain the resin, the latex, the catalyst, the thickening agent, the dyes, and the solvents, which go into the spray application in a single 45 solution or suspension or both. Pretreatments of the raw stock feed, stich as mercerization, scourin- and wet processin@ with chemicals, such as formaldehyde, significantly enhance the properties of the finished product. 50 The many facets of tihs process, and their proper application by adjusting to the most suitable variables make it evident that there are many ad@,antages to be gained in the practice of this invention. The following specific examples refer to materials actually produced on an exppri55 mental basis, and are in no way to be construed as specific limits to the flexibility of the system. The batts produced by the use of this invention are dimensior@ally stable and resilient, and demonstrate a marked ability to reproduce contours of the confining 60 mold used to restrain them during drying and curiiig. Drying temperatures up to 325' F. can be used dependin.- on whether drying will be carried out simultaneously with curing or as a separate unit operation to be followed by curing. In the latter instance drying ri, 5 temperatures up to 220' F. would be adequate for drying if followed by temperatures of iip to 325' F. for curing. Suitable temperatures within this range can be selected depending upon the requirements of the chemicals employed. Evidence exists that the degree of expansion 7t) obtained in the finishejd product depends ijpon a relationship between the time of drying and the temperature employed. In general, longer times at lower temperatures will result in a more expanded structure in the finished product. 75 Upon the completion of the drying and curing step or
[3]5 steps, the product retains its preselected height, width, and length. Furthermore, the product is one having improved resilience, a resistance to deformation from compressive loading much greater than untreated cotton batting, and demonstrates a cohesive structure and resistance tO cOmpaction in use. In addition, the produzt made as a result of the practice <)f this invention has signi&antly greater tearing and tensile strength, up to twenty times as great as untreated cotton batting. The performance of the improved product can be demonstrated both at high and low relative humidities. We have now discovered th@it it is possible to produce shaped or contoured cotton battiiig as well as other cellulosic batting products through the use of the instant process which is the subject of this invention, by placing the layered cotton fiber webs which have been spray dampened with a formulation containing bc)th a thermosetting cellulose reactive crosslinking agent and a thermoplastic film-forming latex, the necessary @catalyst, and a buffer and dye where desired and needed, into expanded metal molds while spray damp, then drying and curin@. at the select times and temperatures which are applicable to the chemicals and conditions chosen. The most essential phase of the process of our invention is the step in the process where the cellulosic batting material must beplaced wet, or spray dampened, into the expanded molds while batting is impregnated with the chemical solution to a wet add-on about from 50% to 150%. This is based on the original weight of the cotton or other cellulosic fibers used. The configurations that we have specifically studied in detail are sirnple to complex concave and convex to planar. These can be formed from a single continuous piece of such spray damp cotton or other cellulosic battin.- in such a maiiner as to permit the fabrication of the cushions for bucket seats, Lipholstered furniture, or the like, by following the process <)f this invention. The density of the finished batt can be made to vary from batt to batt as well as within a unit batt by proper adjustment of the spacing between the male and the female die or mold. Shape-conf arming, resilient, dimensionally stable, -coherent integral units having high tensile and/or tear strength can be prodticed easily, using the formulations which we cite in our examples, bearing in mitid that these are not to be rniscomtrued as limiting m auv manner whatever. Our preferred 100% spray damp wet add-on when correlated with the 20% solids of the cherhical bath can be used as a "point of departure" for computations, since the limits 50% and 150% are of no particular significance if the solids content is not taken into consideration. For example, if a 50% wet add-on is used with a 5% solids solution, the final dry pickup will be very low, while a 150% wet add-on used in correlation with a 25% solids solution (or emulsion) -might be expensive as well as excessive to yield the desirable physical properties. There must be a certain degree of equivale.,ice in these c<)mputations in order to obtain the desired results. Since the resins found to contribute the enhanced properties described herein for cotton fibers are known to chemically react with the cellulose <)f the cotton fibers, such resins can be expected to react equally well with synthetic cellulosic fibers such as rayon. For this reasoln, the process described herein for the manufacture of a fibrous cotton batt is equally applicable to the fibrous cellulosics or blends of these materials with cotton. Such -resins as the urea formatdehydes, tris(1-aziridinyl) phosphine oxide, melamines, triazines, and others will react equally well with wool as with cotton. For this reason the process described herein for the manufa-.ture of a fibrous cotton batt is equally applicable to wool or blends of wool and cotton. Because textile wastes normally used in the production of cotton batting are derived fr<)m diverse sources, amounts of synthetic fibers, such as polyesters or acrylics polyethers or others either by chance or desi,-n. The pres ence of these synthetic fibers would not preclude the ust of the waste in the practice of this invention. 5 In general, according to the invention, the method foi producing a contoured and/or v'ariably compacted fibrous cotton batt with improved stability, coherence, and resilience, comprises the following operations carried out in sequence: 10 (a) forming webs of opened textile fibers of the group oonsisting of cotton fibers, and chemically modi-fied cotton fibers; (b) spraying the webs to a wet add@on about from 50% to 150% with a resinforming composition at least one 15 component of which is a cellulose reactive crosslinking reagent to a resin add-on of about from 3.76% to 24.2% by weight of the cellulosic reactive component, based on the weight of the unsprayed w-;b; (e) placing the spray damp batt, wherein the degree 20 of dampness amounts to at least 50% by weight,'based on the we;,-ht of the unsprayed web, in a confinin.a mold designed to impart to the finished batt a contoured configuration; (d) drying the batt for about from 5 to 30 minutes of 25 time at about from 180' to 220' F.; and (e) curing the dried batt for about from 2 to 30 minutes of time at about from 300' to 320- F. Also, in general, according to the invention, the method for producing a fibrous cotton batt wherein selected por30 tions of the batt exhibit varying degrees of resilience through varying de.-rees of compaction in additi-on to the improved stability, coherence, and resilience obtained through the process,described a'bove the compaction method comprises the same steps described above with the 35 changes in (e) and (e) which must read as follows: (c) placing the spray damp batt, wherein the de,-ree of dampness - amounts to at least 5OVo by weight based on the weight of the unsprayed web in a confl-@iing mold, the cavity of which is nonuniform with respect to thickness; 40 (e) curing the dried batt from about from 2 to 15 minutes of time at about from 300' to 320' F. to produce a batt with varying degree of fibrous compaction. The above general procedure, wherein the webs are formed from mechanically opened cotton fibers and the 45 resiii foraiing composition comprises about I to 4 parts by weight of methylated methylol melamine and I part by weight of vin3r] acrylic polyiner, illustrates one ernbodiment of the invention. The above general procedure, wherein the webs are 50 formed from opened cotton fibers and the resin formin.a composition comprises approximately equal parts by weight of a urea-formaldehyde resin and vinyl acetate copolymer, illustrates a second embodiment. The said general procedure, wherein the webs are 55 formed from opened cotton ers an the resin 9 composition comprises about I part, by weight, of a ureaformaldehyde resin and about I part, by weight, of a copolymer mixture of vinyl acrylic copolymer and styrenebutadiene copolymer, the two copolymers being in the 6o approximate ratio of 3 parts, by weight, of vinyl acrylic copolymer to I part, by weight, of styrene-butadiene copolymer, represents a third embodiment of the invention. The said general procedure, wherein the webs are formed from - opened cotton fibers that have been chemical65 ly modified by the form W formaldehyde treatment (as see U.S. Patent No. 3,046,079, and Chance et al., "Formaldehyde Treatment of Partially Swollen Cotton," Textile Res. J., volurne 31, No. 4, April 1961), and the resin forming component comprises about 7 parts, by weight, 7o -of dimethylol eth@l carbamate and about 3 parts, by weight, of vinyl acetate copolymer, is an illustration of a fourth embodirnent. The said general procedure, wherein the webs are formed from opened cotton fibers that have been chemicalon occasion these wastes may contain varying nominal 75 ly modified by the aforesaid form W formaldehyde treat-
[4]3,350,486 7 nent and the resin formin-. composition comprises approxiniately equal parts, by wei,@ht, of a urea-formaldehyde and vinyl acetate copolymer, represents a fifth embodiment. The said general procedure, wherein the webs are formed from op-.ned cotton fibers that have been mercerized and the resin forming composition comprises approximately equal parts, by weight, of a urea-formaldehyde and vinyl acetate copolymer, represents a sixth, embodiment, The said general procedure, wherein the webs ar-formed from idpened cotton fibers that have be,--n mercerized and the resin forming composition' comprises approximately 7 parts, by weight, of dimethylol ethyl carbamate and about 3 parts, by weight, of vinyl acetate, represents a seventh embodiment. The said general procedure, wherein the webs are formed from mechanically opened cotton fibers and the i-esin forming composition comprises meth@,lated methylol melamine, represents an eighth embodiment. These various embodiments are set forth in greater detail in the following examples-. EXAMPLE I Using a rawstock feed consisting of 60% first cut linters and 40% textile waste made up of 10% willowed picker, 10% willowed sweeps, and 20% willowed fly, a web was made usi-,i@. a sample card. The web was sprayed while on the apron of the card with a treating media consisting of 22.8% solids. The solids consisted of 76% by w,-ight, of methylated methylot melamine and 24% virlyl acrylic copolymer. The wet add-on was approximately 100% by weight of the feed. The resiilting product had therefore approximately 12% resin content (not including the latex), and a density of 2.86 pounds per cubic foot, which was equivalent in weight to a commercial cotton batting of 5.54 ounces per square loot. When this product was subjected to a cyclic compressive loading test to determine the pei,ceiit set, taken after 50 loadings at I pound per square inch, it had an immediate set of II%, under conditions of 60% relative humidity, and an immediate set of 19%, under conditions of 100% relative humidity. One hour later tfiis sample liad a set of 8% or less, under both 60 and 100% humidity co@-iditions. In contrast, an untreated cotton balting of comparable weight subjected to the same test had an immediate set of 41.8% under the conditions of 6001o R.H. (relative humidity) and 45.5% under 100% R.H. After one hour the untreated cotton had a set of 31% iinder the 60% R.H. conditions and 42% under the 100% R.H. Similar disparity in behavior was shown in energy absorption and stability to 15,000 cycles of loading. EXAMPLE 2 Using the same type feed as above and forming a web in a similar manner spraying was then carried out using a spray media containing 17.7% solids. The solids consisted of 58% urea-formaldehyde and 42% vinyl acetate by weight. The resulting sprayed webs were then collected on a reel Nvith condensing being carried out on a web for web basis until 30 webs had been collected. The partially formed batts were removed from the reel by slitting, and theii placed in ftames spaced 3/4 in., I in., 11/4 in., and 11/2 in. apart for drying and curin@ T-he resulting products had densities of 3.22, 2.96, 2.91, an(i 2.58 pounds per cubic foot, respectively, and thirknesses of 1.14 in., 1.30 in., 1.38 in., and 1.45 in., respectively. After 50 cycles of ,compressional loading @a-nd unloading to I pound per square inch, these products had immediate sets of 17.31 13.2,17.1, and 18.9% when the test was run at 60% R.H., and after one hour of recovery had sets of 8.7, 4.6, 5.7, and 12.2%. When this test was run at 100% R@H., the saxnples had immediate sets of 20.0, 30.4, 28.5, and 32.5%, -and etter one hour recovery they had sets of 12.6, 22.7, 20.0,, and 21.6% respectively. 8 EXAMPLE 3 Three companion batts were made from a comparable feed to that described in Example 1, using a spray media r) containing 10% solids, which was made up of 80% methylated methylol melamine and 20% vinyl acrylic copolymer. The batts contained 20, 30, and 40 webs. The still spray damp webs were condensed by compression rolling to a tbickness of about 3/4 of an ineb. They were 10 then placed in frames spaced 11/2 in. apart, and dried and cured. The finished batts had densities of 1.48, 1.71, and 1.93 pounds per cubic foot, respectively. When tested by the cyclic loading and unloading compression test they had immediate set values of 29.0, 26.3, and 26.3% under 15 conditions of 60% R.H., and 30 minutes later the respective values were 22.9, 18.8, and 21.5%. The values at 100% R.H. were 37.9, 41.0, and 37.2%, and these set values 30 minutes later were respectively 27.4, 34.7, and 33.7%. These values were significantly bettcr than those 20 achieved by comparable untreated cotton batts. EXAMPLE 4 Using a comparable feed to that described for Example 25 1, and spraying the iveb from the card with a media containing 18.7% solids, which consisted of 53% ureaformaldehyde, 36% vinyl acrylic copolymer, and 11% styrene-butadiene copolymer batts consisting of 30 webs -were built upon the reel device and condensed on a web '30 for web basis. The partially formed batts were placed in frames spaced 3/4 in. and I in. apart. Following the drying and curing, these batts had densities of 3.46 and 2.94 pounds per cubic foot, respectively. When subjected to the cyclic compressional loading and unloading com35 pression test at 60% R.H., these samples had set values of 9.4 and 12.99o immediately upon completion of the test, and 10 minutes later they had set values of 2.7 and 8.1%, respectively. Under conditions of 100% R.H. the same samples showed sets of 15.Z and 21.0%, and after 'iO 30 mintites i-ecovery these values changed to 8.3 and 16.2%, respectively. (Note: This is a significant improveinent in performance at high relative humidity.) These samples were compressed to 1/2 their original fieight, and stibjected to a temperature of 158' F. for 22 hours, and 45 the set taken measured after 1/2 hour of recovery at ambient laboratory conditions of 60% R.H. and 70-73' F. temperature. The set in this case was 18.9%, and 21.0%, which changed to 8.1 and 9.8%, respectively, after 51/2 hours. 50 EXAMPLE5 The feed for this experiment consisted of 42% textbe waste of various grades including picker, sweeps, and 55 lly, and 58% first cut linters all of which had been scoured and mercerized. A portion of this material was formed into a web, and sprayed with a suspension of 15% solids, which consisted of 50% urea-formaldehyde and 50% vinyl acetate copolymer, and another portion 6o sprayed wit@h a combination solution suspension consisting of 20% solids made up of 70% dimetliylol ethyl carbamate and 30% vinyl acetate copolymer, The product batts were obtained by lapping the web back and forth in a semi-conventional manner by hand until 30 webs 6,5 had been built up in eaeb case. The partially formed batts were condensed by rolling to a thickness of about 1 inch, and then placed in frames spaced 11/2 in. for drying and curing. When tested by the cyclic loading and unloading compression test these samples showed sets of 30.3% and 70 16.7% immediately upon completion of the test at 60% R.H., and 30 minutes later had set values of 10.5 and 8.3%, respectively. When the same test was carried out at 100% R.H., the samples had values of 32.4 and 23.0% immediately, and 28.8 and 19.2% respective values one75 half hour later.
[5]8,350,486 EXAMPLE 6 Scoured but not mercerized raw stock similar to that desr,ribed for Example 5 was treated with fornialdehyde by the wet treatment knovin as ",form W farmaldehyde process," previously ment;oned. In this case a chemical reaction takes -place. The formaldehyde reacts with the celltilose molecule. After washing ;and drying this material it was formed into a web, and a -poition of the web was sprayed with a suspension containing 15% solids, 50% of which was -urea-formaldehyde, and the other 50% vinyl acetate copolymer. Another portion of the web was sprayed with a solution suspension consisti-Tig of 70% dimethylol ethyl carbamate and 30% vinyl acetate copolymer. Batts of 30 webs were rnade ar@d condensed to about I inch, then dried and cured in frames 11/2 inches ,apart. The productshad densities of 1.69,and 1.81 pounds per cubic foot, respectively. The results of the cyclic compression loading test showed that these samples had set valuf s of 19.4 and 21.6%, respeztively, immediately after the completion of the test, and values of set,of 9.7% and 14.9% oiie balf-bour later, under conditions of 60% R.H. T-he set values at 100% R.H. 'were at 29.0 and 21.6% immedi-ately, and 17.7 and 14.9% one-half hour later. EXAMPLE 7 The feed material for this example consisted of 60% first cut linters and 40% textile wastes of various grades similar to those in Example 1. One batt was made by spraying the web with a suspension of a vinyl acFYlic copolymer at a 20% solids content, and one batt was made by spraying the web with a solution containing -methylated methylol melamine at 20% solids content. After spraying, forming, and condensing the batts were placed in frames spaced 11/2 in. In the case of vinyl acrylic copolymer drying only sufficed to set the @resin because it is of the thermoplastic type. In the case of the methylated methylol melamine curing following drying is required, because it is of the thermosetting type. A comparison of these batts on an equal ntimber of webs basis demonst,rates the different characteristics conferred by the two types of resins. At 20 webs the saml>le sprayed with the vinyl acrylic copolymer hereinafter called sample (a) had a density of 1.63 pounds per cu@bic foot, while the sample sprayed with the methylated methylol melamine hereinafter called sample (b) had a density of 1.02 pounds per cubic foot. When these samples were evaluated by the cyclic compression loading,and unloading test ,at 60% R.H., sample (a) -hada set of 33.4% imme,diately upon completion of the test, and 24.3% oiie hour later, while sample (b) had an immediate set value of 27.1%, and one hour later @a set of 22.5%. Under conditions of 100% R.H., the cyclic compression loading test gave an immediate set value in sample (a) of 45.5%, and one hour later 36.4%, while sample (b) had a set value of 38.7% immediately, and 27.4% one hour later. When t,hese materials were tested for heat tolerance under load, sample (a) had a set of 25.0% -one-half hour after testing, and 14.7% 31/2 hours later, while sample (b) had @a'set of 22.5% one-half hour after testing, @and 16.0% 31/2 hours later. EXAMPLE 8 Using a feed matorial similar to Example 1, and spraying the webs with a solution suspension containing 22.8% solids made up of 76% methylated methylol melamine and 24% vinyl acrylic copolymer by weight, hand fomiing batts, and condensing to I inch, followed by drying ai,d curing in frames spaced I inch during dryin.- and 11/2 inch during curing, a @batt was produced which had a density of 1.71 pounds per cubic foot. This @batt was subjected to 15,000 cycles of loading -and unloading at the rate of 132 cycles per minute, and approximately I pound per square inch, The immediate set for this sample was 11.2%, and after recovering for 24 hours at 60% R.H. and 70' F. the sample had a set value of 3.3%. An untreat-,d control cotton batting of comparable weighl showed an immediate set of 40.6%, and after 24 hours the set was 29.7%. The experimental sample showed no tendency to compact under these conditions while compaction was evident in the untreated cotton batting. EXAMPLE 9 Usin.- a feed material sin-jilar to Example 1, and spraying the web as discharged from t-lie card to a wet pickup of 130%, with a solution containing 10% solids, which 10 was made up of 40% methylated methylol metamine and 60% vinyl acrylic copolymer by weight, @a hand forminoperation was perf@ormed to yield a 20 web batt. This batt was condensed to I inch, followed by drying and 15 curing in frames spaced 11/2 inches. The product had a @Tesin a<fd-on of 4.55%,,and had a density of 1 42 pounds per cubic foot, which was equivalent to a c'omniercial batting standard of 2.09 ounces per square foot. T-his product showed a compression set of 35.7% after 50 20 cyclic loadings at a load of I pound per square irich at 60% R.H., and 46.4% at 100% R.H. After 30 minutes of recovery the sample had a set value of 19.6% a, 60% RH., and 39.3% at 100% R.H. The produ--t required a lo'ad of 5.38 pounds - fer a foot 50 square ini@hes on a 25 100 square inch sample to reduce its thickness 25%. When held compressed to 1/2 its normal thickness at a temperature of 158' F. for 22 hours and then allowed to freely recover for 30 minutes at ambient room conditions the batt sliowed a set of 21.4%. This perforinance is better 30 than that of untreated cotton batting as can be seen by referring to the data given in Example 1. F-XAMPLE 10 Using a feed material of the same makeup as shown 35 for Example I the web was sprayed to a wet pickup of about 70% with a media containing 20% solids made iip of 80% methylated methylol melamine and 20% vinyl acrylic copolymer a batt containing 40 webs was formed. This batt was condensed to a th-ickness of about 40 1 inch, then placed in frames spaced 11/2 inches, dried, and cured. The resulting product had a resin add-on of 9.8%, and a density of 1.89 pounds per cubic foot, and was equivalent in weight to a standard untreated cotton battin.a of 3.97 ounces per square foot. This product re45 quired a load of 6.93 pounds load for a 50 square inch foot on a 100 square inch sample to compress it 25% of its original height. When tested for,compression set at 60% and 100% relative humidity after 5G cyclic loadings at I pound per square inch, it had initial s--t values of 12.5% 50 and 31.6%, respectively. Thirty minutes later these values were 10% and 25%, respectively. When held compressed to 1/2 its normal thickness at 158' F. for 22 hours, and t@hen allowed to recover for 30 minutes at ambient room conditions, this sample had a set of 21.2%. By referring 55' to Example 1, it can be seen that these samples perforined better than untreated cotton batting. EXAMPLE 11 Using a feed material similar to Example 1 and spray60 ing the web as it is discharged from the gamett with a SOI@ution containing 10% solids of which 40% was methylated methylol melamine and 60% vinyl acrylic copolymer followed by hand layup, a batt consisting of 30 webs was produced. T-his batt was placed in frames 65 spaced 11/2 inches apart and dried at 200' F. for 90 minutes and then cured at 300' F, for 30 minutes. The resulting cured batt had a resin add-on (excluding latex) of 3.76%, a density of 1.98 pounds per cubic foot and was equivalent in weight to a commercial untreated batt 7o of 3.63 ounces per square foot. This product when tested by the cyclic compression method had a set of 22.8% immediately upon completion of the test at 60% relative humidity, and a set of 46.2% under conditions of 100% Tolat-ive hurnidity. Ten minutes later the values were 75 15.8% and 37.2% respectively. When subjected to a
[6]3,350,486 compression to 1/2 its original thickness at a temperature of 158' F. for 22 hours and allowed to recover for 30 minutes at ambient room temperature, this material had a set of 24.3 %. EXAMPLE 12 5 Using a feed material similar to that used for Example I and spraying the web as it is discharged from the garnett with a solution containin.- 20% solids, all of which was in the form of methylated methylol melamine, a product was produced w@hich had a resin add-on of 24.2%. The IC product required a load of 5.72 pounds on a compression foot of 50 square inches to reduce the thickness of a 100 square inch saniple to 75% of its original thickness. This product had a textile breakin.- strength of 24.5 lbs. 15 in the direction of the fiber lay compared with a textile breaking strength of 5.20 pounds for untreated cotton batting sample of comparable weight. Similar differences were shown when -the treated sample was tested for breakin,,- strength in the direction transverse to the fiber lay and compared with the breaking stren-th of com20 parable wei-ht untreated batting, EXAMPLE 13 Using a feed material similar to that shown for E xample 1 and spraying the web as it is discharged from 25 the garnett with a solution con-ta@inin.- 15% solids of which 60% was methylated methylal melamine and 40% was vinyl acrylic copolymer followed by hand layup, a batt was produced havin,@ 40 webs. This oduct had a Pr resin add-on of 10.2% (excluding latex) after drying and curing in frames spaced 11/2 inches apart. The density was 1.80 pounds per cubic foot, and on a wei,ht basi s - was equivalent to untreated batting of 3.68 ounces per square foot. When tested for compression set under conditions of 60 and 100% relative humidity, this - sample 3,5 had set values of 24.4 and 41% immediately, and values of 20.5% and 37.2% after 4 minutes. This product required a load of 7.48 pounds on a 50 square inch foot to redtice the thickness of the sample by 25%. When cornpressed to 1/2 its orig,'@ntal thickness and held at 158' F. 40 for 22 hours, this sample demonstrated a set due to heat under load of 25.5% permitted to recover for 1/2 hour under room conditions without load. This sample showed a textile breaking strength in the direction of fiber lay of 44 pounds compared with 5.2 pounds for untreated c<)tton 45 batt-ing. EXAMPLE 14 Usin.- a raw stock feed consisting of 60% first cut linters and 40% textile waste, which was made up of 50 10% willowed picker, 10% willowed sweeps, and 20% willowed fly, a web was rnade with a sample card equipped with @.-arnett type wire. The web was sprayed while on the apron of the card with a chemical formulation consisting of 18.3% solids. The solids consisted of 52.1% 55 by wei,-ht of methylated methylol melamine and 47.9% by wei-ht of vinyl acrylic copolymer. The sprayed web had a wet add-on of about 100% by weight of the cotton fed. This spray damp cotton batting was collected on a reel type device (item 11, FIGURE 1B), until a total 6( of 30 webs had been built up. The spray damp material was then removed from the reel and placed in a pair of molds made of expanded metal to simulate the contours of the arm of an upholstered sofa (FIGURES 4A, B, C). Note.-The use of expanded metal for mold parts is 65 in no way critical to this invention. The male and female pieces of the molds were then spaced so that the fini@@hed molded cotton batt-in.- product would have a density to approximately 2.5 pounds per cubic foot. The spray damp cotton inthe confining m<)ld 70 was then placed in a cabinet type oven and submitted to the dryipg step which consisted of heatin.- the material and mold for 2 hours at 200' F., followed by a 20 minute cure at 300' F. The contoured fibrous cotton batt produced here was 75 12 removed from the mold once it cooled to near room temperature, and upon close scrutiny and evaluation was found to have fai@thfully reproduced the contours of the @mold, and exhibited a tensile strenqh in excess of 25 pounds in the direction of the fiber lay, and 15 pounds in the direction transverse to the fiber lay. The resiliency of the contoured fibrous cotto-@i batt produced here was such that it returned to its ori,-,intal shape and position after a series of standard compressive loadin,-s. Untreated cotton batting material which was submitted as control did notdenionstrate sufficient inte-rity to hold a shape unless it was draped over the arm of a piece of furniture. EXAMPLE 15 Using a feed of the type stated in Exam le 14 and a p chemical formulation of the same general composition a spray damp batting having about an 85% wet add-on, based on the dry cotton fed to the sample card, was produced. This spray damp batting was placed in a mold which was specifically designed to simulate an automobile bucket seat (FIGURES 5A, B, C), the two halves of the confining mold being spaced so t-hat a product having a density of 2.4 pounds per cubic foot, was produced, the impregnat ed spray damp material being dried at 200' F. for 2 hours, and cured at 300' F. for 40 minutes. The drying and curing of this experimental product were urider investigation, and known to be excessive. Commercially, the drying time should be about from 2 to 30 minutes at the stated temperature, while the curing time should be about from 2 to 30 minutes at the stated temperatures, depending upon the thickness and density of the finished product. The codtoiired fibrous cotton batt produced here was -removed frorn the mold once it cooled to near room temperature, and upon close scrutiny and evaltiation was found to have reproduced faithfully all of the concave and convex curvatures. This configuration was retained by the product after being submitted to severe handling, which consisted of twisting, pulling, and tearing attempts. The, tensile strength of the product was in excess of 20 pounds in either the machine direction or the transverse direction. The resiliency of this batt with curved configuration was comparable to that of a pad with the flat configuration produced by the process of the aforesaid Patent No. 3,191,225. The recovery evaluations were determined from 50 deformation loading cycles at 1.0 pound per square incb, and 85% recovery was obtained within 4 minutes when the relative humidity was about 60-65%, and 75% recovery was obtained within the same period of time when the relative bumidity was 100%. The bonding and sbape reproducing characteristics of the resins and latexes used in the product reinforce each other in reducing the powdering or dusting out of sbort fibers from the product when it is in use. EXAMPLE 16 Usin- a feed of the type stated in Example 14 and a chemical formulation consisting of 20% scxlids to spray the cotton fibers while these were openly -arrayed on the apron of the card, a product having a varying density at chosen locations was produced. The spray solution was made up of 50% by weight of methylated methylol melamine, aiid 50,llo by weight of solids of vinyl acetate copolymer. This solution was sprayed onto the raw stock feed and a 115% spray damp wet add-on was obtained. This spray damp cotton batt which was made up of 20 webs of sprayed fibers was placed into the female portion of the expanded metal molds shown in FIGURES 4 and 5. The halves of the confining molds were then adjusted so that the density of the product would vary from point to point, with the densest portion in mold A (FIGURES 4A, B, and C) at the transition from flat to curved surface, and in mold B (FIGURES 5A, B, and C) with points of highest den-
[7]3y35O,486 13 sity occurring in the sbarp short curved surface and at the base of the large scooped shaped section. The samples were dried in a cabinet oven for 2 hours at 200' F. and cured at 320' F. for 30 minutes. The fibrous cotton batt wherein selected portions of the batt exhibit varying degrees of resilience through varying degrees of fibrous compaction was removed ftom the mold once it cooled to near room temperature, and upon close scrutiny ar@d evaluation were found to demonstrate a density gradient throughout the product, the greatest density for mold A (FIGURES 4A, B, and C) being at the region where the@-e is transition from flat to curved; and in the case of mold B (FIGURES 5A, B, and C) with the greatest densities occurring at the neck, or small curved section, and again at the base of the large scooped section. This is demonstrated more clearly in FIGURE 6 -where greatest deusity occurred at the thinnest portions of ibe product. These products show excellent resiliency. Efficient and rapid recovery from deformation loading was observed in the evaluation of the products produced by this process. The shape recovering characteristics were considered durable through rotigh handling, and the product had tensile strengths in excess of 20 pounds in the direction of the fiber lay, and 20 pounds in the transverse direction. We
