US 2803577 A
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Description (OCR text may contain errors)
IAug. 20, 1957 E. w. COLT ET AL. 2,803,577
METHOD oF MAKING COMPRESSED ELAsToMER-BONDED HAIR PRODUCTS Filed June 26, 1952 Arrow/Ek United States Patent Oiice Patented Aug. 20, 1957 METHOD F MAKING COMPRESSED ELAST()- MER-BON DED HAIR PRODUCTS Edwin W. Colt, Evanston, and Sidney N. Pinhasik and Frank D. Sulc, Chicago, Ill., assignors to Armour and Company, Chicago, Ill., a corporation of Illinois Application June 26, 1952, Serial No. 295,654
Claims. (Cl. 154-110) :This invention relates to a method of making 4compressed elastomer-bonded hair products, such as underrug pads, cushions, etc.` The method of this invention has particular utilityV in making under-rug pads from hog hair.
Elastomer-bonded hair products for use in upholstering furniture have heretofore been prepared. The general process for preparing such products involves the steps of (1) spreading curled hair either manually or mechanically in a mat or web, (2) spraying the Web with a compounded latex to bind the hair laments together, and (3) curing the sprayed mat to vulcanize the latex. Such upholstering mats are generally prepared in thicknesses of between about l to 4 inches. These mats are generally in the form of at sheets, having densities in the range from about 28 to 46 ounces per cubic foot, and being capable of supporting loads up to about 2.5 pounds per square inch. i
For Ysome purposes, however, it would be desirable to increase the loading capacity of the elastomer-bonded hair mats. One way of doing this is to increase the density of the hair mats, but in order to increase the density of the mats from that obtained by the random positioning of the hair it is necessary to compress the hair mat and set it in compressed condition. Also, in order to form non-rectilinear products such as rounded hair cushions, `etc., from rectilinear blocks of hair, it is necessary to compress the hair blocks and set them in compressed condition. In the course of the experimental Work leading to the present invention it has been found that it is completely impractical to hold the hairmats or pads in compressed condition until the latex is vulcanized, which would normally require from 30 to 60 minutes. To overcome this difficulty it was suggested that the natural latex composition can be dried until it becomes indispersible but before it has cured to any appreciable extent. Natural latex is tacky in this state and has `adhesivity properties. Therefore, it would seem to be feasible to compress the hair mat and hold itin compressed condition until the latex has adhesively bound the hair ftlaments in compressed` condition. Thereafter, the cornpressed hair mats could be vulcanized to permanently bindthe hair. Even when natural latex is employed and it is carefully dried to an indispersible but unvulcanized condition in which it has maximum adhesive properties, it is found that the compressing of the hair mat to preliminarily set it in compressed condition requires an excessive amount of time. Depending somewhat on the degree of compression to which the mat is subjected, it has been found to require as much as 5 to l5 minutes to obtain a complete set at the desired thickness or shape. As thel time interval in which the pad is forcibly held in compressed condition is shortened, the degree of recovery of the pad to its original thickness increases. This rebound effect is both variable and substantial at short time intervals, say in the neighborhood of 1 to 2 minutes. Therefore, it can readily be appreciated that a process employing this operation is not suited for highspeed production lines, such as would be required to produce under-rug pads efliciently. In a continuous production line for under-rug pads it would be desirable to pass the uncompressed hair web over a compressing roll before it has passed into the vulcanizing ovens. The required time of contact with the compressing roll would therefore limit the speed of the entire production line, and contact time in excess of 2 minutes would greatly reduce the commercial value of the process. Compressing rolls of very large diameter could be employed, but these would add to the expense of the equipment and would prevent the operation from being carried out on a; compact production line. The required compressing time to set the hair pads in compressed condition would also be an important factor in molding operations where blocks of latex-coated hair are placed in a mold and compressed to form rounded cushions and other curvilinear shapes.
It is therefore a general object of this invention to provide a method of making compressed elastomer-bonded hair products which are adapted for efcient, high-speed production. More specifically, it is an object of this invention to provide a method by which mats or blocks of hair can be compressed and set in desired compressed condition in a very short interval of time. It is a further object of this invention to provide a method by which a synthetic elastomer can be used in place of natural latex as the primary ingredient of the elastomer-bonding composition in. making compressed elastomer-bonded hair products, even though synthetic elastomers have considerably poorer adhesive qualities when dried to an in-` dispersible but unvulcanized state. It is a specific object of this invention to provide a method adapted forfthe production of under-rug pads which are formed by subjecting hair webs to a high degree of compression on a continuous processing line, and in which all operations are performed Without severing the web. Further objects and advantages will appear as the specication proceeds.`
The method of this invention is shown in illustrative embodiments in the accompanying drawing, in Which- Fig. 1 is a partial diagrammatic view of a production line for making highly compressed elastomer-bonded hair products such as under-rug pads; Fig. 2, the rest of the production line of which the lirst portion is shown in Fig. l; and Fig. 3, a diagrammatic representation of a mold which can be employed for producing compressed curvilinear hair products from rectilinear hair blocks in accordance with the method of this invention. l
The starting material for use in the process of this invention can be designated as curled animal hair. The term hair is used in this specification and claims in its broader sense as referring to tilamentary epithelial tissue composed mainly of keratin, or in other words it includes Wool as well as the other common types of commercial animal hair such as horse hair, cattle hair, and hog hair. Preferably, however, the hair for use in the method of this invention has an average diameter of between about 2.5 to 9.0 mils, which excludes Wool since it has an average diameter of l mil or less. Specifically desirable types of hair from both an economic and functional standpoint are relatively short hair such as hog hair and cattle body hair; however, long types of hair such as cattle tail hair, horse mane hair, etc., can be employed. Excellent results are obtained with hog hair, which can contain a minor percentage by weight of other types of hair such as cattle tail hair. The term curled means that the natural hair laments have had a three-dimensional curvature impressed on them by a curlingprocess. For example, the hair can be curled by the well-known mechanical curling process, or it can be curled by the more recently developed chemical curling process. It is not absolutely necessary that curled animal hair be exclusively employed, although this is desirable. Synthetic fibers or fibers of vegetable origin can be used in minor proportions by weight.
As indicated above, the curling of hair by either mechanical or chemical process introduces a three-dimensional curl in the hair filaments so that a random distribution of the hair on a flat surface produces a stereoreticulate mass thereon which will produce a hair web of approximately the same density for the same kind of hair having about the same degree ofV statistical curl. The curling of the hair is a well-known process and does not constitute a part of the present invention. Therefore, it is believedl that it will not be necessary to further discuss it herein.
The initial step of the present process involves the spreading of the curled animal hair in a layer of the desired thickness. This may be accomplished either man-v ually oir-mechanically, andV preferably the hair is allowed to fall on a horizontal surface so that it assumes a random distribution and forms a hair mat or web of a predetermined bulk density. For the preparation of under-rug pads, a hair web or mat of between about 2 to 3 inches in thickness is preferred, but for the manufacture of hair cushions, etc. somewhat greater thicknesses may be desirable, say upV to about 4 inches.
Referring to Fig. 1 of the drawing, there is shown in somewhat diagrammatic form mechanical apparatus for carrying out the first step of the present process. The curled hair is stored in hopper 10 and fed downwardly onto a slide 11 from which it is discharged into a hair spreader 12. In the illustration given, hair spreader 12 is equipped with wire-toothed carding cylinders 12a and 12b, which separate the fibers as they are discharged from slide 11. Hair spreader 12 lalso includes two lower positioning rolls 12e` and 12d. The fluffy mass of hair H is discharged downwardly by the carding rolls 12a and 12b and positioning rollst12c and 12d onto a continuous conveyor belt 13 where it is formed'into a web W of the desired thickness.
Following the formation of the flat hair mat or web, it is sprayed with an elastomer forthepurpose ofbonding the hair filaments together. One or both sides of the web can be sprayed, and a plurality of spraying on both sides can be used if desired. With webs of about 2 to 3 inches in thickness, it has been found'desirable to spray the web a single timefrom each side. This gives excellent penetration by theliquid elastomer` dispersion and prevents the dispersion from collecting on the conveyor or other supporting surface because thebottorn half of the web acts as a filter during each spraying operation.
Referring again to Fig. l of thev drawing, the web W is shown being carried toward the right from hair spreader 12 by conveyor belt 13 to a spraying station i" or zone 14 wherein one side of theweb is sprayed with the liquid elastomer dispersion. In the illustration given, there is shown a sprayhead 15, which is preferably of the oscillating type so that it moves backL and forth across the web during the spraying operation. Sufficient elastomer is applied at spray station 14 to penetrate the upper half of the web. Immediately thereafter conveyor belt 13 takes the partially elastomer-coated web-through a dryer 16 wherein the elastomer coating ,isdried sufficiently to increase the tensile strengthk of the matv so that it can be inverted4 without` tearing the mat,V and also so that the elastomer coating Lwillnot stick to the conveyor belt or drain downwardly uponit whenthe web is inverted. Ordinarily, the time requiredk in dryer 16 will be between about.l5 to ZOseconds when a dryer of the hot air. blast type is employed. The partially coated web W is then taken over an inverter 17vwhich turns over the web so that the uncoated portion of the web is now uppermost on the conveyor 13. The web is then conveyed through a second spraying station 18 similar to spraying station 14. If desired, it may be equipped with an oscillating sprayhead 19 of the same type as sprayhead 15. Sufficient elastomer is applied in spray station 18 to penetrate to the center of the web and thus complete the distribution of the elastomer throughout the web.
When the elastomer is applied by spraying as preferred, it is found that not only are the individual filaments coated with films or sheaths of the elastomer, but also that the elastomer tends to accumulate at the cross-points or intersections of the hair filaments and to form nodules which effectively lock the hair filaments together. Both the distribution of the elastomer on the hair filaments and the forming of nodules at the intersection of the hair filaments is desired, but it is believed that the nodules are of greater importance in imparting the desired mechanical properties to the hair mat.
Various types of elastomer dispersions can be employed. However, it isv preferred to employ an aqueous dispersion of a vulcanizable elastomer. The specific elastomer employed may be either natural rubber (latex), a synthetic elastomer, or a reclaimed rubber dispersion. The rubber or synthetic elastomer dispersion is com pounded with well-known ingredients to facilitate the application and curing of the elastomer. Water may be added to secure required consistency for application. As indicated previously, when an aqueous dispersion of natural rubber is drie'd to an indispersible state in which it is not appreciably cured, it has a relatively high adhesivity. lt was expected that the property of high adhesivity in an indispersible but uncured state would be essential for the elastomer employed in making compressed elastomerbondedhair products. However, it has now been discovered that when the method of this: invention is employed, and particularly one essential step thereof which will subsequently be described in detail, that a natural rubber elastomer does not possess any substantial advantages over a synthetic elastomer, even though the synthetic elastomer has much poorer adhesive qualities inits indispersible but unvulcanized state. It is desired to emphasize the importance of this discovery, since it permits compressed elastomer-bonded hair products to be made entirely from domestic raw materials. For eX- ample, synthetic elastomer such as butadiene-styrene'dispersions, neoprene rubber dispersions, etc. can be advantageously employed.
Typical formuliof compounded, vulcanizable aqueous dispersions of elastomers are set outv below:
Natural rubber formulation Parts by weight (dry) Naturalrubber latex (62% solids) 100.0` 20% potassium hydroxide solution 0.5 5,0% zinc oxide dispersion 3.0 65% sulphur dispersion 2.0 50% agerite white dispersion 0.5 50% zinc salt of mercaptobenzothiazole 1.0 50% zinc dibutyl-dithiocarbamate i 0.5
Synthetic elastomer formulation Parts byweight (dry) Neoprene latex`(50% solids) 100.0 Aquarex- D 1.0 50% zinc; oxide dispersion 20.0 50%.l ageritefwhitedispersion 1;0 50% zinc dibutyl dithiocarbamate 2.0
v to an indispersible but substantially unvulcaniz'edstate 4of waterin the hair mat is not especially desirable.
is Ato dry the hair mat until the bulk of the water is re' moved from the elastomer dispersion. Generally, it is satisfactory to remove at least about 60% of the water and preferably 80% or more of the water. This can be done very rapidly in a hot air blast drying oven. For example, the time required in the ordinary oven of this type would generally not exceed 15 to 20 seconds. The normal initial moisture content of curled animal hair is around by weight. After application of the elastomer, of course, the moisture content of the hair is somewhat increased. However, after the drying step in which the bulk of the water is removed from the elastomer dispersion, the moisture content of the hair is probably `returned to around 10% or lower.
In Fig. 2 of the drawing the completely impregnated web W after the completion of the operations illustrated in Fig. 1 of thedrawing, is shown being carried into a dryer 20. Dryer 20 is preferably of the hot air blast type and the drying conditions are regulated so that the bulk of the water is removed from the elastomer while the web W is passing through dryer 20. Thus, upon being discharged from dryer 20, the web is ready to undergo the compression step which characterizes the process of this invention.
After completion of the drying operation in which the elastomer is converted to an indispersible but unvulcanized state, the web will ordinarily have a density of between about 28 to 46 ounces per cubic foot. As indicated previously, in order to -increase the density of the web, it is necessary to compress it and set it in compressed condition. A similar compressing operation is required to form curvilinear products from rectangular blocks of hair which can be cut from a tlat web. It has been found to be important to heat the web to a relatively high temperature during the compressing step. This can most advantageously be carried out by contacting at least one of the sides of the web with a heated surface at a temperature between about 212 to 300 F. If desired, both sides of the web can be contacted with heated surfaces and this is preferred. Preferably, at least one of the heated surfaces is at a temperature between about 230 to 280 F., and excellent results are achieved when one or both of the surfaces is at a temperature between about 260 to 275 F. However, in the course of the experimental work leading to the present invention, it has been determined that high temperatures are not alone sufficient for high-speed operation wherein the web is completely set in compressed condition in a minimum of time. In combination with the high temperature it has been found necessary to employ the action of water at or near the boiling point, or preferably to maintain the hair in contact with an atmosphere containing steam during the compressing step. Satisfactory results can be achieved by contacting the hair with water at a temperature of 212 F. or above, but it is preferred to inject dry steam into the web along lines approximately normal to the ilat surfaces of the web simultaneously with the compression step in which at least one surface of the web is contacted with a heated member. The steam should have some degree of super-heat, as condensation The steam can be introduced into the web immediately prior to the compressing step, or the web can be sprayed with hot water which is converted into steam by contact with the heated surfaces in the compressing zone. However, the injection of dry steam along lines normal to the surface of the web simultaneously with the compressing step has been found to give the best results, and is therefore preferred. Among the results accomplished by the contacting of the hair with an atmosphere rich in steam are the following: (l) the heat transfer to the hair web is greatly accelerated; (2) the steam treatment temporarily reduces the bending modulus of the hair and therefore `facilitates the compressing operation; (3) the combina- ;tion of heat and the moist atmosphere superimposes a set to the curl of the hair in the new position, which in effect relieves the undesirable stresses in the hair which tend to produce rebound, while at the same time setting the hair in a condition of high resiliency at the desired thickness.
lt has been determined that for best results the moisture content of the hair during the compressing step should be increased to between about l5 to 25% by weight. However, a sufficiently precise regulation of the moisture content of the hair can easily be obtained by the injection of dry steam as outlinedabove. Moreover, if the injected steam contains sufficient super-heat to raise the temperature of the pad above 212 F. and preferably to between 260 to 280 F., one or both of the surfaces between which the pad is compressed can be at a temperature considerably below 212 F. For example, the injection of steam at 30 to 100 p. s. i. g. can be used satisfactorily even though the compressing surfaces are not heated. The injection of steam along lines substantially normal to the flat surface of the web effectively meters the moisture to the individual hair filaments, thereby increasing their moisture content to greater than 15% by weight, without undue condensation of moisture on the outside of the hair filaments. This even metering of the moisture to the individual hair filaments is believed to be of value in achieving the repositioning and stabilizing of the hair in the compressed condition.
One of the main advantages of using the combination of high temperatures and steam injection in forming cornpressed elastomer-bonded hair products is that the required compression time to completely reset the hair can be reduced to from 25 to 5% of that required if high temperatures alone were employed. A further advantage is that a synthetic elastomer can be employed as the bonding agent even though in its indispersible but unvulcanized state it has relatively poor adhesive properties as compared with natural latex.
Referring to Fig. 2 of the drawing, the dried coated web W is shown passing upwardly from conveyor 13 onto a compressing and embossing roll 22. In the illustration given, roll 22 is heated internally with steam of suicient pressure to maintain the surface temperature of the roll above 230 F., and preferably between about 260 to 275 F. The compression of web W against roll 22 is accomplished by means of belt 23 which travels around a series of rollers 24, 25, 26 and 27 so that it forms with the surface of roll 22 a channel 28 of the desired width to which web W is to be compressed. Belt 23, of course, travels in the same direction as roll 22, as indicated in Fig. 2, and thereby as web W enters channel 28 it is progressively compressed to the, desired thickness and held in this thickness throughout its time of travel through channel 28. While the web W is passing through channel 28 steam is injected into it along lines approximately normal to the flat surface thereof by manifold 35 which rides against the outer surface of belt 23. If belt 23 is of a porous material such as a heavy cloth web, the steam can be made to penetrate through the belt into the hair. Alternatively, a perforated belt can be employed so that the steam will pass through manifold 35 through the perforations in the belt into the hair web. Of course, if desired, other means of introducing the steam can be employed, such as introducing it through the surface o roll 22, etc.
The compressed web W is discharged from channel 28 and carried through curing or vulcanizing oven 30 by means of conveyor 29. At temperatures between about 230 to 240 F. in the vulcanizing oven, from 20 to 40 minutes will ordinarily be required to complete the vulcanization. If desired, lower temperatures can be employed with longer times. For example, at 220 F. a time `of around l hour may be required to complete the vulcanization. The finished rug underlay is indicated in Fig. 2 by the number 31, as it isdischarged from the curing oven 30.
Ablocks -movable platen 32 and a stationary platen 33. platens 32 vand 33 are heated -by steam, and platen 33 molded. vpad R is indicated in dotted lines prior to the compress- AInthe manufacture of under-rug pads-bythe Vmethod of1this invention, it has'been found desirable to -emboss atleast `one surface `of the hair web during the compressing step. This can be easily accomplished by employing a compressing roll having a three-dimensional patternon the surface thereof. lFor example, roll 22 in Fig. 2 of the drawing is shown provided with a rippled or corrugated outer surface 22a. Various patterns can be embossed on the surfaces of the rug underlay in this manner, such as diamond shaped patterns, etc. The simultaneous embossing and Acompressing of the web has been found to kbe greatly facilitated bythe method of this invention. The forming of the surface pattern on the web can be rapidly accomplished by the joint use ofsteam and high temperatures, as described above. The value of embossing'the ,surface of the web is that it increases the tensile strength of the under-rug pad, gives it better resiliency, and improves'its rolling properties.
This invention is particularly adapted for producing under-rug Ypads from curled hog hair. VWhen it is employed `for this purpose, the mat of' hair `formed on the conveyorY should be between about l.5 to 3.5 inches and preferably -from about 2 vto 3 inches in thickness. This web is then compressed to a thickness of between about .2 to .8 inch or preferably from about 3%; to S; inch. The density of the viinished padis increased to about 75 to 110 ounces per cubic foot from the density of the uncompressed web which will usually be between about 28 to 46 ounces per cubic foot. Because of this high degree of compression7 the repositioning and stabilizing of the hair by the action of the steam-containing atmosphere and high temperatures of the compressing surfaces is especially important. For randomly distributed hair on the conveyor belt, it can be assumed vthat substantially the same percentages of the hair lilaments are oriented in all directions. For example, the vertical and horizontal component ofthe randomly distributed hair mass would be approximately 50-50. However, on decreasing the thickness of the hairweb by 4 to 6 times, as is required for the production of under-rug pads, the vertical component ofthe hair viilarnents is greatly decreased. For example, the vertical component of the hair filaments in the highly compressed under-rug pads may be considerably lessthan 10%. 'When ahog hair web is compressed from -2 inches to f/s inch, it has Vbeen found `that the vertical component of the hair is around 6%. The combined action -of steam and high temperatures, however,
-eiectively -repositions and stabilizes the hair with this lradically altered alignment of the lilaments.
The hair web either before or after the compressing and curing steps can 4beeasily'cut with rotar-y cutters to pro* duce a firm edge. Therefore, the finished under-rug pads can be readily `cut in the desired length, or prior to the compressing step the web can be cut into rectangular for individual molding operations to form cushions, etc. In Fig. 3 of the drawing, there is shown somewhat diagrammatically a molding press P having a Both is provided with a `plurality of apertures 33a through which steam is discharged into the hair pad as it is being In the illustration given, a rectangular hair "pressed condition, valve 1Min the steam line of stationary -platen 33 is opened so that steam passes into hair pad R through apertures 33u. v -forming the hair pads into curvilinear products such as hair cushions are .substantially thetsame asthose pre- The desirable temperatures for viously described for forming under-rug pads. Therefore,
it is'believed that it will knot be Ynecessary -to Vrepeat .the discussion `'of :these conditions at this-point. However,.if desired both thefiniection of steam and-the heatingrof the cushion can beterminated well ahead of the opening of the mold. The molded cushion can then be somewhat cooled by blowing'or sucking relatively coolairfthrough it for several Vseconds before opening the mold. A molded hair cushion C isindicated to the right of mold `P-in Fig. 3. It Vwill .Abe understood that the molded hair cushion is-then rpassed tota vulcanizing or.curing oven such as oven 30 yof Fig. 2 to vulcanize the elastomer therein.
While in the foregoing specification `.specific embodi ments of this inventionlhave lbeen set out in considerable detail for thefpurpose of more clearly illustrating the principle underlying this invention, it will be understood that many of the `details set-forth ycan be varied `widely without departing from lthe spirit of this invention.
l. In a method Vof making a compressed elastomerbonded hair product from a hairmat consisting of 4a stereoreticulate Vmass of curled animal hair `having a vulcanizable elastomer :distributed thereon, the steps Vof drying said hair mat until said elastomerbecomes indispersible but thas `not appreciably vulcanized, subsequently increasing the moisture content of said hair by contacting it with an -atmosphere containing water, and compressing said mat while .infsaid moist condition at a temperature of at least 21.2 1F., whereby said hair mat can -be permanently set in compressed condition in a .very short interval of time.
2. ln a method `of makinga compressed elastomerbonded hair productfrom alhair mat consisting of a stereoreticulate mass of curled animal hair having Yan aqueous dispersion ofa vulcanizable elastomer distributed in nodules at the intersections of the filaments, the steps of drying said hair-mat `until said `elastomer reaches an indispersible butsubstantially unvulcanized state, subsequently increasing themoisture content of said hair to at least 15% by weight by contacting Vsaid yhair mat with an atmosphere containing steam, and compressing said mat while in said moist condition at .a temperature of at least 230 F., kwherebysaid hairmat can be permanently set in compressed condition in a very short interval of time.
3. The methodsteps of claim 2 in which said elastomer is a synthetic elastomer.
4. In a methodof `making a compressed elastomerbonded hair product vfrom a 'hair mat consisting of a stereoreticulate mass of curled animal hair having an aqueous dispersion ofa vulcanizable elastomer 'distributed in nodules at the intersections of the laments, the steps of drying said yhair `mat until said yelastomer becomes indisperlsible but is not appreciably vulcanized, and then compressing said hair mat by contacting .it 4with at least one `surface heated to a temperature above 230 F. while simultaneously injecting steam -into said mat .to vincrease the moisture content thereof, -whereby said hair mat can be completely set in compressed condition in a very short interval of time.
5. The method steps of claim in which saidelastomer is a synthetic elastomer.
6. In a method of making a compressed elastomerbonded hair product from .a hair mat consisting primarily of a stereoreticulate mass of curled hog .hair hav- `ing an aqueous dispersion of a .vulcanizable elastomer distributed on the` hairflarnentsand formed-into nodules at the intersections ofthe 'laments, said mat of curled hog hair being .inthe formio'f va flat, thin .web, vthe steps of drying said hair mat until said ,elastomer reaches an indispersible unvulcanized condition, then compressing said mat to reduce its Vthickness and :increase its density bycontacting atleast .one of the fiat` surfaces of said mat withasurface at a .temperature of .at least :230 F. while `simultaneously injecting steam into .said mat to increase 2u,so34,577
the moisture content of the hair filaments therein to at least 15% by weight, whereby said hair mat can be permanently set in a highly compressed condition in a very short interval of time, and subsequently vulcanizing said elastomer.
7, The method steps yof claim 6 in which said elastomer 1s a synthetic elastomer.
8. In a continuous process for making an under-rug pad from a hair web consisting of a stereoreticulate mass ot curled animal hair having an aqueous dispersion of a vulcanizable elastomer distributed in nodules at the intersections of the hair filaments, the steps of continuously passing said web through a drying zone wherein said elastomer is dried to an indispersible but substantially unvulanized state, thereafter continuously passing said dried web over a compressing roll having its surface heated to a temperature of at least 230 F., compressing said web against the surface of said roll while simultaneously injecting steam into said web, whereby said hair web can be permanently set in a compressed condition in a very short interval of time, and subsequently vulcanizing said elastomer to make said compressed web suitable for use as an under-rug pad.
9. The method steps of claim 8 in which said elastomer is a synthetic elastomer.
10. In a method of making a curvilinear elastomerbonded hair product from a rectilinear hair mat consisting of a stereoreticulate mass of curled animal hair having an aqueous dispersion of a vulcanizable elastomer distributed in nodules at the intersections of the hair filaments, the step of compressing said rectilinear hair mat in a mold having at least one of the molding surfaces thereof heated to a temperature above 230 F. while simultaneously injecting steam into said mat, whereby a curvilinear shape can be permanently impressed on said rectilinear hair mat in a very short interval of time.
References Cited in the file of this patent UNITED STATES PATENTS 2,430,868 Francis Nov. 18, 1947 2,455,534 Talalay Dec. 7, 1948 2,480,851 Goss Sept. 6, 1949 2,502,361 Zeigler Mar. 28, 1950 2,541,868 Gordon Feb. 13, 1951 2,580,202 Talalay et al. Dec. 25, 1951 2,582,915 Sebok Jan. 15, 1952