US1783435A - Manufacture of rubber goods from rubber dispersions - Google Patents

Description

Dwz, 1930.

MANUFAGTURE P. K LEIN ET AL 1,783,435

OF RUBBER GOODS FROM RUBBER DISPERSIONS Filed April 15, 1927 /7 f lh Patented Dec. 2, 1936 UNITED A sfrfrrfi'sv PATENT. oF-Flcr.

age-UL xnrum'or BUDAPEST, HUNGARLAND ANDREW. szEevARI, or AxRoNgzoHIo, AssrGNoRs 'ro AMERICAN ANonEr-Nc., or AKRON, omo, A CORPORATION or DELA- MANUFAGTURE or RUBBER eoons FROM RUBBER nrsrnnsrons Application filed -April 13, 1927, Serial iNo. 183,606, and `in` Hungary and Germany April 14, 1926. .I

In the manufacture of 'rubber .goods by electrophoretic precipitating of rubber from` rubber dispersions on the anode, or on a precipitating backing or support 'surrounding the anode," gases are liberated at lthe Cathode dwing to the electrolysis which takes place simultaneously with the cataphoresis. The gas bubbles escaping from the cathode may reach the rubber precipitate and adhere to it, there- '10 by impairing the uniformity of the rubber coating. Although it is ,possible to prevent the gases liberated at the cathode from reaching the rubber precipitate by inserting delecting walls or diaphragms lbetween the cathode and the precipitating backing, this method may be unsuitable, or even impracticable under certain conditions, especially in the manufacture of closed hollow articles such as inner tubes of tires.

-According to this invention in thecataphoretic device means are provided to pre` vent the liberation of gas atthe cathode during cataphoresis. ing lat the cathode may be used suppressing the generation of hydrogen. Forl this purpose oxidizing depolarizing agents may be v' used.

example, lead peroxide. AThe hydrogen ions cathode is used, the surface of which consists of a metal oxide, which is'easilyireduced, for

discharging at the cathode reducethis oxide surface. Preferably'the cathode consists of lead, the surface of which has been converted to lead peroxide, for example, by means of the well known storage battery process.-

.l1-b, preferably having a removable lining,

for example, of'zinc. The two halves-11a For example means act- According to this invention, preferably a and 11b, of the mold are detachably joined in any suitable manner, for example, by bolts 17. l is the annulancathode Within the mold which is interrupted at 19 and has a shaft 7 to attach the cathode to the mold. The cathi vode consists preferably of an iron tube with 'an outer coating of lead. The layer of lead is formed in the well known manner, which is used for storage battery plates so that a porouslayer of-lead peroxideis generated on its surface. In order to prevent the crumbling of this surface coating, the cathode can ,be covered with a protective coating of any material permeable or semi-permeable to'liqnids, for example, a coating of gelatin. The tubular cathode is preferably provided with an opening '16 diametrically'opposite to the shaft 7, or with a plurality of openings. The shaft 7 of the cathode isV inserted in the mold and sealedwater-tight by means of a stuffing 'box 8 having an insulating lining. Itcan be firmly' attached-to the carrier 5 by meansY of any suitable device, for example, the threaded box 4 having insulatinglinings 2 and 6. The carrier 5 Ais rigidly 'connected to the one part 11b of the mold in an exactly .centered posi- When the mold has been put together as' described'abovq and is in the horizontal position,"it is filled through the tubular cathode 1 with therubber dispersion. This rubber dispersion enters the mold through the opening 16, and the air escapes from the mold throigh the tube 9. When the hollow of the mold islled with rubber dispersion up to 'the lvel'of the mouth of the tube 9, the tube l is attached by the terminal 3 to the negative pole of a source of current, and the mold l1 is attached by terminal 2() to the positive vpole so that the rubber is precipitated on the inner wall of mold l1. The liquid canalso circulate continuously. through the mold during the cataplioresis and'escape at 9, but it is preferable to check the circulation so that only the necessary amount of ow is maintained to permit formation of a uniform precipitate.

lBy suitable choice of the metal of the inner wall of the mold 11, for example by use of zinc, and by suitable composition ofthe rubber dispersion, formation of gas at the anode can be prevented in the-well known manner. It will be understood that the electrophoretic precipitation must be conducted as known per se in sueha way that no gas is developed on the precipitation surfaces.Y For this purpose instead of'using metallic precipitating molds, a porous non-conducting Water permeable depositing mold can be used, for example, in the manner described in Patent No.

1,548,689. This non-conducting mold can be connected to the electroconductive anode by a layer of electrolyte, either free or absorbed in a non-liquid material. The hydrogen ions discharging at the'cathode 1 are combined with the lead peroxide layer on the cathode so that no gases are set free in the hollow -of the mold.

When a relatively thick precipitate has been formed, the flow of rubbersolution through the tube 1 is stopped, and the mold is rotated on the pivot 13 to an angle of about 180O in the direction of the arrow 21 vinto the position indicated by chain lines. AIn this way the stuffing box 8 withthe tube 9 is turned downwards. The liquid is then drained from the mold up to a residue of a few drops. The

tube 1 can then be connected to a, hot air conduit so that the hot air enters through the opening 16 of the cathode and escapes through tube 9, thus circulating through the mold and drying the precipitated rubber. The mold is then opened. vAfter loosening the threaded box 4, the shaft 7 is disconnected from the l cathode, and the elastic hollow tube formed by precipitated rubber can be removed from the mold together with the cathode in its interior. The elastic annular tube can be stripped off from the cathode owing to the interruption 19 of the ring forming the cathode. The tube made in this manner can be cured in the usual way. 'Ihe term, rubber dispersion,7 includes all natural or articial, vulcanized or uri/vulcanized dispersions of Irubber, gutta percha, balata, and the like a cathode immersed in the aqueous dispersion and capable of inhibiting escape of gas at the cathode, whereby gases normally liberated at the'cathod'e are prevented from entrainment with the deposited rubber layer.

2. The process for the manufacture of hollow rubber goods from aqueous dispersions of rubber by elect-rodeposition of rubber with an exteriormold-formed surface which comprises lconfining a body of the aqueous dispersion in a closed container constituting the anode, preparing a cathode by associating with it a depolarizer, electrodepositing a `rubber layer from an aqueous rubber dispersion utilizing said prepared cathode immersed in the dispersion whereby gases normally liberated at the cathode are reduced by said'depolarizer and inhibited from'entrainment with the deposited rubber layer.

3. The process for the manufacture of hollow rubber goods from aqueous dispersionsv of rubber by electrodeposition of rub ber which comprises con'fining'a body of the aqueous dispersion in a closed container constituting the anode, electrodepositing a rubber layer from an aqueous rubber dispersion utilizing a lead peroxide-coated cathode immersed in such dispersion, whereby gases normally liberated at the cathode react with the lead peroxide and are inhibited from entrainment with the deposited rubber layer.

4. The process for the manufacture of hollow rubber goods from aqueous dispersions of rubber by electrodeposition of rubber with an exterior vmold-formed surface which comprises confining a body of aqueous dispersion in a closed container constituting an anodic surface of an electric cell, depositing by an electric current traversing said dispersion .through the intermediary of a cathode immersed therein a layer of rubber upon said surface, and reducing the gases formed at the cathode to inhibit the entrainment of gases in the rubber layer deposited.

5. The steps in the process of making hollow rubber articles by electrodeposition from aqueous rubber dispersions with an exterior mold-formed surfacewhich comprises conlining a quantity of aqueous dispersion in contact with surface capable of producing the exterior contour of the hollow article, depositing by an electric current traversing the said dispersion through the intermediary of a cathode immersed therein a layer of rubber upon said surface, and oxidizing the gases formed at the .cathode to inhibit their entrainment in the rubber layer deposited, whereby gases normally liberated at the cathode are reacted with said agent and inhibited from entrainment with the deposited rubber layer.

6. Apparatus for the manufacture of hollow articles comprising a mold adapted to contain an aqueous dispersion of rubber, and having an interior anodic surface upon contain an aqueous dispersion of rubber, and l which a layer of rubber is adapted-to be deposited by electrophoresis, a cathode disposed within said mold, and means associated with the .cathode for preventing the liberation of gases formed at the' cathode, whereby gases normally-liberated at the cathode are inhibited from entrainment with the deposited rubber layer.

7. Apparatus for the manufacture lof hollou'T larticles comprising a mold adapted-to having an interior anodic surface upon which a layer of rubber is adapted to be deposited by electrophoresis, and a lead cathode disposed within said mold having a surface coating of lead peroxide, whereby gases normally liberatedat the cathode are reacted with said agent and inhibited from entrainment with the deposited rubber layer.

8. Apparatus for the manufacture of hollow articles by electrophoresis comprising a sectional mold having a small'duct commuy. nicating with the outside when sections are closed, and a hollow cathode disposed within said mold and provided' with means for the passage of aqueous dispersion of material to be deposited therefrom into the mold, whereby said dispersion can be supplied to and distributed in said mold prior to and during the electrophoretic action.

' 9. Apparatus .for the manufacture of hollow articles by electrophoresis comprising a sctional mold having a small Vopening when sections are closed, and a hollow cathode substantially centrally disposed within said mold when its sections are united and proivided with means for uniformly distributing' a'fiuid in and through the mold, whereby said dispersion can b e supplied to and distributed in said mold prior to'and during the electrophoretic action.

10. Apparatus for the manufacture of hollow annular articles by electrophoresis comprising an annular sectional mold comprising an anode, and an annular cathode disposed within the mold, and insulated therefrom and means associated with the mold and the cathode for circulating the material to be deposited through the mold@ ll. Apparatus for themanufacture of hollow annular articles by electrophoresis comprising an annular sectional mold comprising an anode, and an annular cathode disposed within the moldl and insulated therefrom, and means associated with the cathode forinhibiting the liberation of gases formed at the cathode.

In testimony whereof we affix our signatures. v

PAUL KLEIN. ANDREW SZEGVARI.

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