US 1472244 A
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. cient length Patented "Oct. 30, 19 23. a
JOHN iANDREW DALY, OF NEW PAT aen wea January 22, was.
DENTURE PROCESS 00., INC., A CORPORATION OF I D COATING.
No Drawing. Application flled' llay 1, 1822, Serial No. 557,651.
To whom it mag camera:
Be it known that I, Joiriv A. DALY, a citizen of the Unitetf States, residing Rochelle Park, New Rochelle, in'the county of Westchester and State of New invented certain new and useful Improvements in Coating, of which the following is a specification.
he invention relates to the coating of vulcanite or similar plates with metals such as gold, silver platinum, tin, etc., and has as an object t e application of a metal to a plate of such material so as to be inseparable therefrom.
further object of the invention is the placing of a coating of metal upon a plate of the nature mentioned in such a manner that the metal will exist not only upon the surface df the plate but to a within the body thereof. 1
To prepare the plate for the treatment b it is first thoroughly cleaned from any foreign matter, especially such as is of a greasy nature, and to this end may be immersed in or scrubbed with soda or lye. The plate is'then immersed in some substance which has the power of dissolving the vulcanite, as for instance chloroform, alcohol, acetic acid, or a mixture thereof, and is allowed. to remain therein a sufiiof time for the material of the plate upon its surface and for a slight depth therebelow to become, softened by the action of the solvent. This will usually take place in about twenty minutes.
The third step in the practice of the invention is the cleansing of the plate from p on.
the solvent, for which purpose it may be merely washed with water.
Fourth, the plate immediately after wash ing is placed in an aqueous solution of gold chloride, silver nitrate, or a dissolved salt of the metal which is to be deposited-there- In the case of silver or gold about a 20% solution is found to give good results. In the solution of the metallic salt about 10% of potassium solved and a reducing agent, such as oxalic or a 'tannic acid is added thereto.
The metallic salt in the presence of potassium sulphide and the reducing agent will The metal seems to have an affinity for the sub- York, have h slight extent b sulphide (K S) is dis ,metal is precipitated softened surface.
stances supplied to the rubber for its vulcamzation iii-such a in the soluthe accomfresh metal thereon at each treatment, withoutan additional bath in the vulcanite solvent. After sufficient metal has been deposited on the plate to make the surface thereof an electric metallic salt. I e chemical reactions which take place in the carrying out of the invention are very complex and difiicult of explanation. Apparently in the presence of potassium sulphide a double sulphide of gold and potassium is formed, which sulphide is reduced by the reducing agent with the. consequent precipitationof the metal upon and within the body of theplate.
'nor changes may be made in the steps of the process without departing from the spirit of the invention.
1. The process of coating a body of vul canitewith metal which comprises softening the surface of the body by ch and causing a precipitation of a metal upon and below the softened surface of the body.
2. The process of coating a body of vulcanized rubber with a metal which .comprises softening the surface of the body by treatment with a solvent, immersing the ody in an aqueous solution of a salt of the metal and a .reducingagent, whereby the upon and below the The process of coating a body of vulcanized rubber which comprises cleansing the body, treating the surface thereof with a solvent until the material softened to a slight depth,
removing the solvent, treating the body with an aqueous emical means of the body is ioo ' solution of a nletallic salt containing a reexceedingly-finest'ete of subdlvisioh' is deducing agent, whereby :the metal in en ex posited upon end belovfthe'surfaee of the ceediqgly fine state of subdivision 1 s debody.
v posited upon and below the surface of the 5. Thehfoces's of'coatlhg ahatdnom I metallic body with metal, which comprises.
' 4,- Th'e roce'ss of coating e body of vul- .treatlxig the surface of the bodyto soften eaxiized rubber with metal which comprises the same we 'sl-ight depth,depositin meteltreatingthe body with .a solvent untilthe ,in anexoeecli gly 'fine state of sub iyision -sm'faee thereofissoftenecl to e'slight depth, uponend beneath the softened surface of 'iemoving thesolvent, immersing the thus thehodyto produce a film structurally-intreated body' in an aqueous solution of 'a eorpora'tedwith and overlyihg the surface salt, of the .metel'," potassium sulphide, -and .of the body. A e 4 a. reducing agent whereby the 'm'ettil in an JOHN ANDREW DALY.