Патент USA US2134172код для вставки
Oct. 25, 1938. w. c. CALVERT 2,134,172 APPARATUS FOR MANUFACTURING RUBBER HYDROCHLORIDE FILMS Filed March 20, 1937 2 Shee'ts-Sheet l m Oct. '25, 1938. w. c. CALVERT 2,134,172 APPARATUS FOR MANUFACTURING RUBBER HYDROCHLORIDE FILMS Filed March 20, 1937 2 Sheets-Sheet 2 QN | | T. ._.L______.._____.__. L | a M M01, IL| l-C l1/////c2777 6? 00/1/6713! WW3 ‘Patented 0a. 25, 1938 2,134,172 UNITED STATES. PATENT OFFICE 2.13am maas'rns roa MANUFACTURING nnssaa ' - nrpaocnmamz mars - William C. Calvert, Chicago, IlL, assignor, to ' Wingfoot Corporation, Wilmington, Del.,acor- , poration of Delaware Application March 20, 1937, Serial No. 132,188 40lalms. (CI. 18-15) invention relates to apparatus for the > The invention will be-further explained in con manufacture of a substantially continuous ?lm Junction with the accompanying drawings, where of rubber hydrohalide from a solution or disper ‘in Figure 1 is an elevation, partly in cross-section, sion thereof in a low boiling liquid vehicle. More of the ?lm-forming apparatus; Figure 2 is a plan, 5 particularly it relates to apparatus for the pro also partly‘in cross section, and Figure 3 is a duction of a thin ?exible transparent film of a detail of a modi?ed form of the apparatus. It is rubber hydrochloride. The ?lm is produced by applying the ‘rubber not intended by the illustrative reference to the hydrochloride dissolved or otherwise dispersed in other devices capable of accomplishing the same 10 a liquid vehicle to a suitable surface, as for ex ample a moving belt or drum, in the form of a thin layer of liquid and thereafter voiding said thin layer of its liquid vehicle content, under ' carefully controlled temperature conditions, by a 15 process of evaporation. To effect rapid volatiliza ' tion of the liquid vehicle, without, however, boil ing it or in any other way permitting the forma tion of air or other bubbles which would adverse ly affect the strength and appearance of the ?lm, 20 the solution or other dispersion of the‘ rubber use of a moving belt to limit the invention thereto, or similar results being available in lieu thereof, as may in any given case be desired. Referring to the drawings, the tank I is for storage of the cement; that is, the solution of the rubber hydrochloride in the low boiling solvent. The cement is supplied through pipe la, prefer- 15 ably by gravity but otherwise if desired, to the nozzles 2, from which it flows onto the continu ous belt 3, which passes over and is supported by cylinders 4- and' 5, of which the latter is driven by the motor 6. Instead of supplying the cement 20 through a plurality of nozzles in a header. as or otherwise applied to the belt or drum, where shown, one or two reciprocating nozzles may be it is allowed to remain until sufficient of the liquid employed to distribute the cement in front of vehicle has been evaporated to form a ?lm strong the spreader ‘I. The depth of the ?lm II. is con 25 enough to retain its shape without stretching or trolled by the position of the spreader l; the 25 becoming otherwise distorted when removed from -width, by the position of the guides 8. hydrochloride is advantageously spread, sprayed the belt. ~ It has been found that the ?lm can be removed . from the‘ belt or drum before all of the liquid ve 30 hicle has vaporized and that ‘by doing so the dry ing is hastened because of the fact that the liquid vehicle may then evaporate from both surfaces of the ?lm. The production of the ‘?lm is there . The length of the belt 3 and the rate at which it travels will depend upon the nature of the‘ sol vent employed, the concentration of the cement, and the temperature maintained within the dry 30 ing chamber 9. The operation should be so regu lated that when the ?lm II is removed from the belt 3 as the latter returns over cylinder 4, it has fore divided advantageously into two manufactur- , su?lcient body to maintain itself without distor 35 ing stages, in the ?rst of which the ?lm is carried tion as it passes through the second stage of the by the belt .or drum and in the second of which it supports its own weight. In general, it is ad ?lm drying operation. . This second stage takes place in drying chamber ll. , vantageous to evaporate at least about 80% of After the ?lm is removed from the belt 3 and enters drying chamber l0, it is carried over and under rolls l2 and I3 and subjected to the ?nal v40 drying operation. If preferred, instead of em ploying only two drying chambers, three or more may be used, in which event the ?lm, after pass _ the liquid vehicle before removing the ?lm from 40 the‘ belt or drum.' As the liquid vehicle evaporates from the ?lm, it tends to form a layer of vapor which clings to or remains in the neighborhood of the ?lm and thus retards further evaporation. The rate of 45 vaporization of the liquid vehicle is increased by circulating air in contact with the ?lm as it dries. It has been found that by drawing off a part of the air used in drying and re-circulating it with in the system, the rate of evaporation may be 50 increased without increasing the air intake or the load on the condensers employed for recov ering the liquid vehicle from the exhaust gases. According to the preferred form of this invention, such an air re-circulation system is provided in 5:; connection with both drying stages, the air used in the second drying stage for the ?nal vaporiza tion of liquid vehicle from the ?lm being em ployed in the ?rst stage in the removal of the liquid vehicle from the solution while it is still so supported by the belt or drum. ing through the chamber I0, is subjected to fur ther drying in subsequent drying chambers. The rolls l2 and I3 are driven by suitable driving mechanism It operated by the motor IS in such manner as to relieve the ?lm II from any unde sired strain during the drying operation. Instead of passing the ?lm over and under 50 rollers in the drying chamber Ill,v it may be sup ported by other means. For example, it may be supported only at the edges and thus held taut as it passes through the chamber. Clips may be used for this purpose, which automatically re lease the ?lm as it leaves the drier. One satis 55 factory arrangement comprises two endless chains supported by. gears or shafts which replace the , rollers 12 shown ' in the drawings. The gears should be placed somewhat further apart at the so 2 8,184,178 entrance to the drying chamber and somewhat nearer together near the exit to allow for shrink age of the ?lm during drying. At each link of each chain a spike 4| such as that indicated in Fig. 3 is provided on the inner side of the chain 40 and perpendicular to the plane of the chain. These spikes 4| puncture the ?lm as it enters the drying chamber and the ?lm is lifted oi! of the spikes as it leaves the chamber. Rollers may be rubber cement is applied to the belt 3, a consider able portion of it is drawn oi! up through the air duct 3l-by the blowers 32 located in the compart ment 33. Steam coils 34 or other heating means are provided to heat the air as it passes through this blower chamber. The steam, is advantage- - ously introduced to di?erent sections of the coil from a header and the amount of steam intro duced to each section controlled by a valve so that provided to aid in puncturing the ?lm if neces the heat supplied may be carefully regulated. 10 sary. The margins of a ?lm so dried may be re The heated air is returned to the drying chamber at a point closely adjacent to where the air from the chamber l0 enters the chamber 2. The heated moved by trimming the film as it leaves the drier in order to give an impervious sheet. The trim mings may be dissolved and added to the cement 15 used in forming a new ?lm so that there is no waste. ‘ Adjacent to the chamber III air re-circulation apparatus I6 is provided for re-circulating the air is advantageously returned to the chamber 3 through two or more ducts 35 to insure uniform 15 distribution of the re-circulated air in the air coming from the drying chamber ll. As the cement dries and the ?lmforms, the air used for drying the ?lm. The blower l1 driven amount of vapor given off by the ?lm decreases. by the motor it blows air into the chamber is, The highest concentration of vapor is found im which forms the lower half of the re-circulation mediately above the belt 3 as it enters the cham ber 9. For this reason the vapor takeoif 23, which apparatus It. It is separated from the upper por tion of the re-circulation chamber by the baiile 20 connects with the condenser. is so located that it and is separated from the drying chamber It by removes the air and vapor from the chamber 3 the perforated baille 2|. The perforations serve at a point near where the belt and ?lm enter the to distribute the re-circulated air throughout the drying chamber 9. The duct 3| which withdraws length of the chamber and prevent the setting up the air to be re-circulated is somewhat removed of air currents which would tend to distort the from the vapor take-01f 23 but ordinarily will be located nearer cylinder 4 than cylinder 5. While ?lm. The air used for drying is preferably passed in the solution on the belt is still liquid the rate of a direction substantially counter-current to the vaporization of the solvent is much higher than direction of the passage of the ?lm II. It is after it has become plastic. . The duct 3| is there introduced into the system through the ?lter 22 fore advantageouslyspaced such a distance from and after being used in the chamber Ill passes the cylinder 4 that ?lm passing under it is in a to the chamber 9 and then out through the vapor plastic rather than a liquid state. Although'in the speci?c embodiment shown in outlet 33 to the condenser 24. The fresh air in troduced through the ?lter 22 mixes with the the drawings but two drying chambers have been air in the chamber Iii and is then drawn oil’ shown with a single air re-circulation system for each, it is to be understood that a larger num through the blower I1 and returned to the cham ber of drying chambers may be provided and if 40 ber I0 through the perforated bai?e 2|. Two shutters 25 and 25 control the ?ow of air to the desired more than one‘air re-circulation system may be provided in connection with each cham blower. The air which enters through the shut ter 25 is heated in passing over the steam coils 21 ber. For example, instead of the single air and the air entering through the shutter 25 is I re-circulation system shown in connection with drying chamber 9, the air returned through the 45 not heated. By controlling the position of the shutters 25 and 26, the amount of air passed over ducts 35 may be taken off from the end of the steam coils 21 is regulated and the temperature drying chamber 0 below the cylinder 5 and the air withdrawn through the duct 3! may be re in the drying chamber III is controlled. turned to the upper portion of the chamber 3 The ?lm l l as it passes from the drying cham above the cylinder 5. In this case the duct 3| ber 9 to the drying chamber l0 carries a low per centage of volatile solvent. This is vaporized in might be somewhat closer to the cylinder 4 than the chamber l0 and the ?nished ?lm is then rolled in the case where a single air re-circulation sys onto the roller 28. The air in the drying cham- ' tem is provided, as shown in the drawings. The air re-circulation not only hastens the ber III is therefore charged with a relatively low percentage of vapor and may advantageously be vaporization‘ of the solvent by causing the re employed in the removal of solvent from the ?lm moval of the solvent vapors from proximity to on belt 3. For this purpose, it may pass as shown the ?lm as the solvent evaporates, but the thor ough circulation of the air throughout each from the chamber Ill through the connecting pas sage 29, formed within the shield 250, into the chamber tends to keep the temperature within each chamber substantially constant and thus 60 chamber 9. It is introduced into the chamber 3 at the point where the ?lm leaves the chamber insures uniform drying. Both chambers are ad and passes back’ over the belt 3 in a direction vantageously well insulated. Heat supplied by ‘generally counter-current to the direction in the steam coils 21 and 34 compensates for any which the belt 3 is driven. The chamber 0 is heat lost through radiation and maintains each chamber at the temperature designed to give ‘most 65 divided into an upper and lower portion by the baffle 30 which extends from side to side of the e?lcient vaporization. By this method and using apparatus of this chamber 9 and extends almost the whole distance between the two drums 4 and 5, so that the air type. a substantially continuous, transparent ?lm entering through the passage 29 must travel the may be made from a cement prepared as herein _ length of the bottom of the chamber 9 before it after outlined. Two pounds of plasticized pale crepe rubber ‘passes up to the upper portion. Before'the air which comes up over the drum are dissolved in 31.3 pounds of benzene, giving a 5 from the bottom of the chamber 8 passes back dispersion of approximately 6% concentration. The cement is cooled to about 10° C. and hydrogen to the portion of the drying chamber 9 closely ad 75 Jacent to the spray nozzles 2 through which the chloride gas is bubbled through it, with stirring, 20 25 30 85 45 70 II 2,184,172 for about six hours or until the increase in weight of the composition due to the introduction of hydrogen chloride has been about 1.16 pounds. The hydrogen chloride and rubber are then al lowed to react at room temperature until a sample which has been washed and dried indicates on analysis 29 to 30.5% of chlorine. Generally this takes about 20 hours. The resulting cement is then steam-distilled to remove the benzene and the greater part of the uncombined hydrogen chloride. The mass of in completely saturated rubber hydrochloride is then broken up on a rubber mill and washed thoroughly with water and dried in a vacuum at approxi mately 160° F. It is then dissolved in about 20 parts by weight of chloroform to which an anti oxidant or other age resister has been added. A suitable age resister is a mixture of 3% of ditetra hydro furfuryl amine or dicyclo hexyl amine and 20 11/2 % of hexamethylene tetramine. Any of these three compounds used alone prolongs the life of the ?lm, but mixtures give better results. This solution is then stored in the tank I and supplied to the belt through the nozzles 2 at the desired 25 rate. Instead of supplying the cement through nozzles it may be applied to the belt by brushing, or, in suitably designed apparatus, by dipping the belt in the cement, or in any desired manner. In forming the ?lm the evaporation of solvent. is carried out at a temperature below 142° F., the boiling point of the chloroform, until suilicient solvent has been vaporized to ‘eliminate any danger of the solution boiling and the ?lm thus formed is then heated to over 142° F. to insure removal of all traces-of solvent. If a pressure above _or below atmospheric is employed the tem perature is varied accordingly. Using a cement of the composition above-described and applying sui?cient of it to the belt to form a rubber hydro chloride film 1,6000 of an inch thick, if the belt is 50 feet long and the temperature in the drying chamber 9 is maintained at about 140° F. and if the belt travels at a speed of 12 feet per minute, the ?lm, with adequate air re-cirulation, will dry 45 su?iciently in traveling the length of the chamber 9 and back again so that it contains about 10—12% of solvent. It then can be removed from the belt and further dried by festooning in the drying chamber In, in which the temperature is main 60 tained at about 160-180" F. The cement as ?rst applied to the belt cannot be subjected to the latter temperature, as it would cause too rapid evaporation of the solvent and the production of imperfections in the ?lm due to bubbling, etc. 55 By the two-stage drying operation herein dis closed the ?lm is rapidly and thoroughly dried and I5 minutes after the solution has been applied to the belt, the ?nished ?lm may be wound on the roller 28. 60 " A ?lm prepared in this manner is non-tacky and substantially moisture proof and is resistant to acids and alkalis. It is'resilient and is not damaged by creasing. It may advantageously be used as a wrapping material and for various 65 other purposes. Instead of chloroform, other sol vents such as benzene,' carbon tetrachloride, dichlorethylene, etc. may be used. This application is in part a continuation of my application Serial No. 685,724 ?led August 70 18, 1933. It is of course to be understood that numerous variations may be made in the apparatus which 3 , constitutes the preferred species of the invention and in the conditions of operating it, as well as in the nature of the film thereby produced. It is intended that the patent shall cover, by suitable expression in the appended claims, whatever features of patentable novelty reside in the in vention. I claim: 1. Apparatus for the production of a trans parent ?lm of a rubber hydrochloride which com 10 prises two drying chambers, two drums in the ?rst chamber, a continuous belt passing over the drums, means for applying a solution of the rub ber hydrochloride to the belt, a condenser, a vapor outlet from the ?rst drying chamber con necting said chamber with the condenser, means for conveying the ?lm from the belt to the second chamber .and for passing gas from the second chamber to the ?rst chamber in contact with said ?lm, means for introducing ?ltered air into 20 the second chamber and means in the second chamber for supporting the ?lm to permit simul taneous evaporation of liquid from both sides of the ?lm therein. 2. Apparatus for the production of a trans 25 parent ?lm of a rubber hydrochloride which com prises two drying chambers, two drums in the ?rst chamber, a continuous belt passing over the drums, means for applying a solution of the rub ber derivative to the belt, a condenser, a vapor 80 outlet from the ?rst drying chamber near said means and connecting with the condenser, means for conveying the ?lm from the belt to the second chamber and for passing gas from the second chamber to the ?gst chamber in contact with said ?lm, means for introducing ?ltered air into the second chamber, air re-circulation means con nected with each chamber and means for heating the re-circulated air. ' 3. Apparatus_for the production of a trans parent ?lm of a rubber hydrochloride which com 40 prises two drying chambers, two drums in the ?rst chamber, a continuous belt passing over the drums, means for applying a solution of the rub ber derivative to the belt, a condenser, a vapor 45 outlet from the ?rst drying chamber near said means and connecting with the condenser, means for conveying the ?lm from the belt to the second chamber and for passing gas from the second chamber to the ?rst chamber in contact with said film and means in the'second chamber for supporting the ?lm and exposing both surfaces thereof to contact with the gas in said second drying chamber. 4. Apparatus for the production of a thin ?lm of a rubber hydrochloride which comprises two drying chambers, in the ?rst chamber a continu ous surface on which the ?lm is to be formed, means for imparting uniform motion to said surface, means for applying a solution of the rubber hydrochloride to said surface, a condenser, a vapor outlet from the ?rst chamber connecting said chamber with the condenser, means‘ for con veying the ?lm from said surface to the second chamber and for passing gas from the second chamber to the ?rst chamber in contact with said ?lm, and means in the second chamber for sup porting the ?lm to permit simultaneous evap oration of liquid from both sides of the ?lm therein. . WILLIAM C. CALVERT.