US 1902953 A
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March 28, 1933. HAZELL 4 1,902,953
METHOD AND APPARATUS FOR THE MANUFACTURE OF FILAMENTARY MATERIAL Filed March 11, 1931 INVENTOR Hifilf Z ATTORNEY Patented Mar. 28, 1933.
UNITED- STATES PATENT OFFICE mum! mz LL, or NEW YORK, N. Y., AssIoNoR 'ro REVERE RUBBER comrramr, or PROVIDENCE, REonE-Ismmn, A CORPORATION or RHODE ISLAND METHOD AND APPARATUS F018. THE MANUFACTURE OF FIIAMENTARY MATERIAL v I Application filed March 11, 1831'. Serial No. 521,641.
This invention relates to the production of filamenta material of desired shapes from .aqpeous dispersions of rubber in a manner w ich is simple and economical and by means of which the shape of the filament produced ma be accurately controlled and regulated. object of the invention is to provide a process and apparatus for forming continuous filaments of rubber from aqueous rubber dispersions. Another object is to provide means for forming continuous rubber filaments having any desired cross-sectional shape, more particularl filaments having cross sections the boun aries of which are straight lines. A further object is to provide a process and apparatus for forming from' an aqueous dispersion of rubber, continuous rubber filaments which are suitable for use in elastic webbing, clothing,'etc., as well as for use in other manufactures such as'the windin of golf balls.
n the manufacture of rubber filaments by streaming aqueous dispersions of rubber into a coagulating medium, as taught, for instance 2 by the atent to Hopkinson and Gibbons,
1,545,25 granted July 7, 1925, it has been found desirable to accurately determine and purposes it is desirable to f manufacture a 80 round filament, for others a filament of square cross section, and for others one of rectangular cross section or one which is half round and half flat or semi-circular in cross sec- 7 tion. A number of factors enter into the sucoessful production and re lation of such shapes, 1m ortant amon w ich is the shape of the ori ce through w ich the rubber material is streamed.
I have found that in spinning or forming 9 a filament of a desired cross sectional shape, it is necessary, in order to obtain a preferred cross section, to accurately predetermine the shape of the cross section of the spinnerette or nozzle. For instance, although a square sha ed nozzle will form or spin a substantia sma orifice is used, the surface tension of the liquid rubber dispersion tends, in the for mation of larger filaments, to draw the exposed surface into a shape which presents a ately after formation, the surface, control the shape of the filament. For some 1y square filament, especially when a very minimum bounding area. Ifhus the tendency of the surface of a filament formed or spun by streaming through an orifice of any particular shape is to assume the cross sectional con-tourof 'a circle, the smallest boundary for the givencross sectional area. In order to counteractthistendency I have devised orifice shapes which'varytosome extent from the proposed finished cross sectional contour of the'filament to be made, but which so de liver the stream of material that its subsequent tendency to assume a cylindrical shape is utilized to give the exact shape desired.
When an aqueous-dispersion of rubber is streamed into a coagulant through a square orifice, the coagulated rubber filament is, as above indicated, slightly difierent from the cross sectional shape of the orifice, unless the orifice is of extremely small dimensions.-
Depending upon the particular conditions of formation, the thread may vary from a circular cross section to one having straight sides with rounded corners. Apparently the immediate action of the coagulant is to form a rubber skin at the surface leaving the center in a more or less fluid condition. Immedibeing still moldable to some extent, exhibits the natural tendency of a tensioned surface to alter its shape to expose the shortest possible bound ary over a given area or to present a circular cross-section. Whether the cross section is round or merely has rounded'corners is dependent to some extent on various factors such as the size of the thread, the speed at which it is drawn through the coagulatin bath, and the rate of coagulation, all 0 which affect the rate of coagulation of the center of the thread. The shape of the orifice and the pressure or head "under which the material is formed or spun are other factors upon which accuracy and control in result must be based to some extent, as hereinafter indicated.
Figs. 1 and 2 illustrate the contour of an orifice designed to give threads whose cross sectional contours are square and rectarggutaken at right i outwar ly concave sides section of an orifice with concave sides tend to assume the sha as indicated in cross section in Fi .4. When such orifices are used the action 0 streaming a coagulable liquid into a coagulant is to form a skin at the surface. Surface tension forces then act to reduce the boundaries to a minimum and fora given area the ultimate boundary of a cross section of material will e of a circle. As ce, the shape of the the stream leaves the ori where an aqueous surrounding rubber skin,
- dispersion of rubber is used, is very closely thickness of the cusps trates these cusps toa substantial'extentand .designed to Due to the reduced the coagulant penelike that of the orifice.
forms relatively r1 id corners at these points, after which the si es tend to approach a circular cross-sectional shape so that the sharp projecting angle of the cusp at each corner is widened to a right angle concurrently with the movement 0 the concave sides as they bulge outwardly. By proper adjustment of the rate of drawing the thread from the nozzle into the'coagulent, it is possible to obtain a suflicient depth of coagulation to overcome further changes in cross sectional shape due to surface tension forces and-to make the stream sufficiently rigid to hold its own shape at the time that the forces have drawn the surface boundaries into the shape of a square or of a desired figure.
It should be noted that the head or pressureon the streamed liquid and the rate of drawing it away from the nozzle into the coa ulant are factors which must-be considere in the regulation and control of thread size and shape. For example a high pressure and low rate of pulling will result in the production of a round thread regardless of the sha of the nozzle due to the fact that the sur ace tension forces have ample time to contract the surface into the form of a circle. With a low pressure and high rateof pulling the coagulant strikes back along the.
inner surface of the nozzle and .more efficiently coagulates the outer layer or surface of the material into a cohesive skin which conforms to the shape of the nozzle. This action is important in an understandingof the present invention and it should be under-,
stood that the pressure and rate of pulling should be so ad usted that the material spun through nozzles shaped as herein set out is coagu ated at the surface as quickly as possible. The rate of withdrawal may be regulated by va g the speed of the apparatus andle the thread after-forma-- tion. This may be in the form era are:
tered and such alteration or curved boundaries intermixed is laid or through which it is run. In this manner the rate of coagulation may be albe accomplished by altering the strength of the coa' lating bath. The'pressure may bevaried. y providing a feeding system for the streamed liquid which can be adjusted to give varying pressure heads.
It should be noted that the invention is not only applicable to the production of square control may also and rectangular thread from nozzles of the shape desired, production of threads or bands of' other shapes bounded by straight lines, for example triangles, parallelograms, polygons, etc.
' Further by controlling and reducing the rate of drawing the thread from the nozzle and mcreasing t e head under which it is extruded, may be formed instead of but also can be applied to the straight lines. By the use of longer cusps I and more deeply concaved sides a thread may,
for example, be produced having small cusps and somewhat concave sides if produced under the same conditions of rate of withdrawal and pressure as described above in the production of square and rectangular. material. It should. be noted also that the invention is well adapted to the formation of strips, bands or sheets of rubber which may be subsequently cut into desired sizes. 1
Filaments produced by this invention are more satisfactory for weaving into elastic webbing etc. than round filaments. The sharp, even corners characterizing the square or rectangular thread made in accordance with this invention enables fibrous material to be spun,-twisted or wound around the rub-' ber'filaments and hold its osition thereon, whereas round thread used or the same purpose has been found to allow the fibrous teria'l to slip after twisting or weaving about such rubber filaments. Moreover, thread is not desirable for certain manufactures such as golf balls, and by this invenround I tion a tough unmilled rubber thread of square or flat cross section may be made which is well adaptedito the production of these and other articles.
Rubber thread formed by means of the present inventionresists chafin in winding as in the manufacture of golf ba centers and incorporation in articles and therefore r I in processing during such as elastic webbing,
ossesses advantages over rubber thread made rom'crude'fsolid rubber by cutting vulcanized sheets. The latter. has ragged corners whereas thread made in accordance with this invention has absolutely smooth and uniform corners. agents, accelerators, anti-oxidants, fillersand other compoundinigaigredients may be added to the aqueous ru r dis ersions used therewith: '1'-"fthe formation 4 hill and
- v It is of course understood that vulcanizing means of rubber articles in accordance with the principles herein set out, the may be dried and vulcanized by any suitab e means.
' The invention is not limited to the particu- 6 l'ar embodiment illustrated but is capable of.
. adaptation into various combinations, and
sub-combinations, withoutdeparting from Having thus described my invention, what Tclaim and desire to protect by Letters Patent 1. The process of making rubber filaments from an aqueous dispersion of rubber which comprises streaming said dispersion through an orifice having outwardly concave sides and cusped corners.
2. The process of making rubber filaments from an aqueous dispersion of rubber which comprises streaming said dispersion through an orifice having outwardly concave sides and cusped corners at a rate greater than the natural rate of flow of aqueous liquid and under a substantially low ressure head.
- 3. The process of making rubber filaments from an aqueous dispersion of rubber which comprises streaming said dispersion through orifices having outwardly concave sides and cusped corners while regulating the rate of wit drawal from said orifices. i
from aqueous dispersions of rubber which comprises streaming a dispersion through orifices having outwardly concave sides and on d corners while regulating the rate of wit drawal from said orifices, and the pressure under which such streamin is effected.
5. The process of making rub r filaments from aqueous dispersions of rubber which comprises streaming such a dispersion through orifices havmg outwardly concave sides and, cusped comers, while regulating the pressure under which such stre is effected, and the rate of coagulation of the streams.
6. The process of making rubber filaments from an aqueous dispersion of rubber which comprises streaming said dispersion into a coagulant through; an orificehaving outward- 1y concave sides and projecting cuspedcorners.
7. The process of making rubber filaments from an aqueous dispersion of rubber which comprises streaming said dispersion into a ly concave sides and cus comers ata rate greater than the natur rate of flow of the aqueous liquid and under a substantially low premure head. e5 7 8. The process of making rubber filaments cus 4. The process of making rubber filaments,
coagulant through an orifice having outward- Y from aqueous dispersions. of rubber which comprises streaming such a rsion into a coagulant through orifices havmg outwardly concave sides and cusped corners, and then gerying said and vulcanizing the rub- 10 r. c r
9. The process of making rubber filaments from aqueous dispersions of rubber which comprises streaming such a dispersion into a coagulant through or ces having outwardly concave sides an cus corners while regulpting the rate of 'wi drawal from said orices.
10. The process of making rubber filaments from aqueous dispersions of rubber which comprises streaming such a dispersion into a coagulant through orifices having outwardly concave sides and cusped corners while regulating the rate of withdrawal from said orifices, and the pressure under which such streaming is effected. g
11. The process of making rubber filaments from aqueous dispersions of rubber which comprises streaming a d' rsion into a coagulant through orifices havlngputwardly concave sides and cusped co ers while regulating the pressure under which such streaming is efl'ected and the rate of,coagulation of the streams. a
12. The process of making rubber filaments from aqueous rsions of rubber which comprises streaming a dispersion through orifices having outwardly concave sides and corners regulating the pressure under which such streamin" is efiectuated and the rate of coagulation d the streams, and then said streams and vulcanizing the ru ber.
13. The process of making rubber filaments from aqueous dispersions of rubber which comprises streaming a d' rsion into a coagulant through orifices havmg outwardly concave sides and cus corners regulating the ressure under w ch such streaming 1s efectuated and-the rate of coagulation of the 1m streams, and then drying said streams and vulcanizing the rubber.
14. As a new article of manufacture, a thread forming nozzle for extrusion of neousdispersions of rubber having an o ce whose cross section delineates outwardly concave siggs and cusped corners.
a new article of manufacture, a thread forming nozzle for extrusion of aqueous dispersions of rubber having an orifice o defined .by outwardly concave sides and cusped corners, and in'which the inner surface of the nwzle ad'acent to the orifice is normal to the plane 0 the orifice. v
Signed at Passaic, county of Passaic, State 125 of- New Jersey, this 13 dayloEf Februa' 1931.
, EARD Y LL.