Classifications

• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D3/00—Electroplating: Baths therefor
  • C25D3/02—Electroplating: Baths therefor from solutions
  • C25D3/30—Electroplating: Baths therefor from solutions of tin
  • C25D3/32—Electroplating: Baths therefor from solutions of tin characterised by the organic bath constituents used
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D233/00—Heterocyclic compounds containing 1,3-diazole or hydrogenated 1,3-diazole rings, not condensed with other rings
  • C07D233/04—Heterocyclic compounds containing 1,3-diazole or hydrogenated 1,3-diazole rings, not condensed with other rings having one double bond between ring members or between a ring member and a non-ring member
  • C07D233/06—Heterocyclic compounds containing 1,3-diazole or hydrogenated 1,3-diazole rings, not condensed with other rings having one double bond between ring members or between a ring member and a non-ring member with only hydrogen atoms or radicals containing only hydrogen and carbon atoms, directly attached to ring carbon atoms
  • C07D233/08—Heterocyclic compounds containing 1,3-diazole or hydrogenated 1,3-diazole rings, not condensed with other rings having one double bond between ring members or between a ring member and a non-ring member with only hydrogen atoms or radicals containing only hydrogen and carbon atoms, directly attached to ring carbon atoms with alkyl radicals, containing more than four carbon atoms, directly attached to ring carbon atoms
  • C07D233/12—Heterocyclic compounds containing 1,3-diazole or hydrogenated 1,3-diazole rings, not condensed with other rings having one double bond between ring members or between a ring member and a non-ring member with only hydrogen atoms or radicals containing only hydrogen and carbon atoms, directly attached to ring carbon atoms with alkyl radicals, containing more than four carbon atoms, directly attached to ring carbon atoms with substituted hydrocarbon radicals attached to ring nitrogen atoms
  • C07D233/14—Radicals substituted by oxygen atoms

Definitions

• This invention relates to a method of electrodepositing bright tin, and to an acid solution suitable as an aqueous electrolyte for performing the method.
• the primary brighteners of the invention cooperate with secondary brighteners which improve brightness and/ or widen the cathode current density range in'which the deposits have the desired brightness.
• wetting agents are employed in the acid tin plating solutions of the invention.
• Non-ionic wetting agents are preferred, and the water soluble ether of polyglycols which are readily available are both effective and stable under the normal operating conditions of the electrolyte. They may have from ten to thirty ethyleneoxy radicals per molecule, the molecular weight being mainly limited by considerations of solubility.
• the primary brighteners are listed in part in the Merck Index, 7th ed., with their methods of preparation.
• the compounds not listed in the Index may be prepared according to the following publications:
• concentrations of tin and free acid may be varied generally within the limits conventional in this art.
• a tin content of 10 to grams per liter, and a free acid concentration of 20 to 200 grams per liter are typical of the sulfate, fluoborate, and aromatic sulfonate solutions, known in themselves, which may be provided with the brighteners of the invention.
• Sulfuric, fluoboric, and aromatic sulfonic acids may be present simultaneously in the electrolytes in a manner not novel in itself.
• the secondary brighteners which are employed in conjunction with the olefinic primary brighteners in the tin plating solutions of the invention include formaldehyde and certain imidazoline derivatives which may be employed singly or in combination with each other.
• the imidazoline derivatives which have been found to Widen the bright and semi-bright current density range are of the formula R is hydrogen or the radical CH COOH, and R is hydrogen or a monovalent metal, particularly an alkali 3 metal.
• the metal may be replaced by hydrogen in the acid electrolyte, and other brighteners of the invention containing carboxyl groups or sulfo radicals may thus be incorporated in the electro- (III) Furfurylideneacetone or 4-(2-furyl)-3-butene- 2-one o-Methoxycinnamic acid 2-furylacrylic acid lyte in the form of their salts.
• the temperature of the plating solution is preferably Grams/m6 held below C. for best stability, but the maintenance 35 stannous Sulfate of a specific operating temperature in the tin electrolytes cresolsflfcmc aeld 260 is not critical for the production ofbright coatings.
• Fermalm "1 2” The following examples are further illustrative of the Ether 9 Polyg yeol "'1' present invention, and it will be understood that the in- Benzyhdeneaeetone vention is not limited thereto: 40 Bright deposits were obtained at 20' to 30 C. over a current density range from 1 to 4 amps. per sq.
• Example 1 The ether of polyglycol employed as a nonionic wetting Eight plating solutions'were prepared from stannous agent was thg Same as Example sulfate, sulfuric acid, formalin (aqueous formaldehyde solution of approximately 37% HCHO content), a poly- Example 4 v ethyleneglycol wetting agent, and an olefinic brightener A tin plating solution that gave a very bright tin elecas indicated in Table I.
• decimeter has the following composition: tin plates were electrodeposited from the several acid plat- Grarns/ liter 1 ing solutions are also listed in the table.
• Tin as fluoborate 40 The wetting agents employed were ether of polyethoxy- Fluoboric acid 80 ethanols which contained approximately 11 C H O radi- Wetting agent 2 cals in solutions 1H, IV, and VI, approximately 15 C H O Pyridy-lideneacetone 0.3 radicals in solutionsV, VII, and VIII, 25 C H O radicals Formalin 1 in solution II, and 30 C H4O radicals in solution I.
• Example 5 A bright tin plating solution was prepared from the following materials:
• the bright cathode current density range extended from 1 to 4 amps/sq. decimeter.
• the wetting agent employed was a ether of polyethyleneglycol containing approximately 15 C2H4O radicals per molecule. Omission of the pyrocatechol from the bath resulted in smooth, but less bright deposits.
• Example 6 TABLE II Plating Solution No. Composition, grams/liter IX X XI XII Tin (as sulfate) 30 40 35 35 Sulfuric acid (free) 100 130 100 150 Wetting agent 6 7 6 6 Formalln 1. 5 0.8 PyrocatechoL 0. 8 Brightener A 0.25 0. 4 2 0. 3 Brightener B"..- 0. 05 0. 6 1. 1. 0 Temperature, C 20-30 18-30 20-30 20-35 Current density amps. per sq. decimeter 1-4 0. 8-3. l-4 1-4 The wetting agents in solutions IX to XH had approximately 1015, 30, 25, C H O radicals per molecule respectively.
• the olefinic brighteners A were benzylideneacetone (IX and XII), furfurylideneacetone (X), and 2- furylacrylic acid (XI).
• the imidazolidine derivatives employed as brighteners B may be prepared by the method of US. Patents 2,528,378, 2,773,068 and 2,781,354, and were of the formula A substantial broadening of the bright plating range was achieved by the addition of the imidazoline derivatives as compared to otherwise identical solutions not containing an imidazoline derivative. This effect was noticeable not only in the range of fully bright deposits, but also in the semi-bright range. The use of formaldehyde is not absolutely necessary when imidazoline derivatives are employed as secondary brighteners.
• Example 7 The imidazolidine derivatives of the invention are equally elfective as secondary brighteners in tin plating solutions which contain sulfuric, fiuoboric, and aromatic sulfonic acids as conductivity increasing and ionization repressing agents. Fully bright tin electrodeposits were obtained from a solution of the following composition under the operating conditions indicated:
• brightener B was-an imidazoline derivative of the formula shown in Example 6 in which R was C H R was CH -COONa, R was sodium. Omission of brightener B from the composition reduced the bright plating range, and particularly the semi-bright plating range.
• Example 8 A stock solution was prepared to the following composition:
• the imidazoline derivative employed was the same as in Example 6, D(.
• the three plating solutions were used at temperatures between 20 and 30 C. and gave at least semi-bright, smooth deposits at cathode current densities from 0.5 to 4 amps. per square decimeter (about 4.5 to 36 amps/sq. ft.).
• a method of electrodepositing bright tin on an article which comprises making said article the cathode in an aqueous solution including a soluble tin salt, free acid, a nonionic wetting agent, and eifective amounts of primary and secondary brighteners, said primary brightener being a compound of the formula X--CH CHY, wherein X is phenyl, furfuryl, or pyridyl, and Y is a member of the group consisting of hydrogen, formyl, carboxyl, alkyl, hydroxyalkyl, formylalkyl, and acyl radicals of carboxylic acids, said compound being dissolved in said aqueous plating solution, and said secondary brightener including at least one member of the group wherein X is wherein X is wherein X is wherein Y is wherein X is 8 consisting of formaldehyde and imidazoline derivatives'of the formula wherein R is an'alkyl radical having at least five carbon atoms
• said wetting agent is a water soluble ether of polyglycol.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Electroplating And Plating Baths Therefor (AREA)
• Electromechanical Clocks (AREA)

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Cited By (16)

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Citations (2)

Family Cites Families (2)

• 0
  • NL NL124247D patent/NL124247C/xx active
  • NL NL134963D patent/NL134963C/xx active
• 1963
  • 1963-08-28 DE DESCH33772A patent/DE1242427B/de active Pending
• 1964
  • 1964-08-05 DE DESCH35588A patent/DE1246346B/de active Pending
  • 1964-08-24 GB GB34585/64A patent/GB1022746A/en not_active Expired
  • 1964-08-24 US US391790A patent/US3361652A/en not_active Expired - Lifetime
  • 1964-08-27 NL NL6409945A patent/NL6409945A/xx unknown
  • 1964-08-27 CH CH1121664A patent/CH449372A/fr unknown
  • 1964-08-28 BE BE652405D patent/BE652405A/xx unknown
• 1968
  • 1968-02-07 NL NL6801713A patent/NL6801713A/xx unknown

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