Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C309/00—Sulfonic acids; Halides, esters, or anhydrides thereof
• • 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

Definitions

• the present invention concerns improvements in or relating to tin-plating and in particular toelectroplating compositions for use in the electrodeposition of tin or tin-alloys on metal, and particularly on iron and steel substrates, especially the electrolytic production of tinned sheet, and to electroplating by using such compositions.
• the present invention provides a process of producing an additive for a tin-plating bath which comprises sulphonating phenol and/or cresol and thereafter heating the resulting snlphonated product for at least one hour without adding further phenol or cresol, at a subatmospheric pressure and at a temperature within the range of from 120 to 190 C.
• the tin-plating additive obtained according to the process of the present invention has been found to be greatly superior to previously-known additives especially in re spect of the current density range over which acceptable plating can be achieved.
• the present invention also provides an additive for a tin-plating bath, which additive is produced by the process of the present invention.
• the present invention further provides a tin-plating bath comprising a source of tin available for electroplating, and an additive produced by the process of the present invention.
• the present invention still further provides an electroplating process which comprises electrodepositing tin using the tin-plating bath of the present invention.
• the present invention provides a process of producing an additive for a tin-plating bath comprising two consecutive stages, namely:
• the initial sulphonation step may be conveniently effected by first melting the phenol and/or cresol and adding thereto, at an elevated temperature for instance a temperature within the range of from 60 to C., the sulphonating agent preferably, whilst stirring the mixture.
• the sulphonation reaction is preferably taken to completion by heating the reaction mixture at a further elevated temperature for instance a temperature within the range of from to C.
• the phenolic starting-materials for use in the process of this invention are advantageously of technical grades. If a mixture of phenol and cresol is used as starting-material, such a mixture preferably contains predominately the cresol component. More preferably however, the phenolic starting-material consists entirely of o-cresol.
• chlorosulphonic acid or a commercially available grade of stabilized sulphur trioxide may be used, if desired, but it is particularly advantageous to employ oleum, preferably containing at least 60 percent by weight of sulphur trioxide, as the sulphonating agent.
• the subsequent heating of the sulphonated product may be conveniently elfected by slowly raising the temperature of the reaction mixture to a temperature within the preferred range of from 120 to 165 C., and heating the mixture within this temperature range under subatrnospheric pressure for at least one hour. It is particularly preferred When carrying out this post-sulphonation heating procedure to effect the heating at a temperature of about to C., a pressure of about 5 to 24 millimetres of mercury pressure and for a period of about 4 hours or even longer, for instance up to 20 hours.
• a pressure of about 5 to 24 millimetres of mercury pressure and for a period of about 4 hours or even longer, for instance up to 20 hours.
• the crude reaction product after cooling may then be advantageously added directly to a tinplating bath in solid form or as an aqueous solution prepared therefrom.
• EXAMPLE 1 150 g. of phenol were melted and gradually reacted with 132 g. of oleum (60%) at 70 C. sulphonation was continued for 1 hour at 100 C. while stirring, and the resultant phenol sulphonic acid was then slowly heated in vacuo to 155160 C. at 11 millimetres of mercury pressure, to keep the distillation of phenol to a minimum. Condensation under vacuum was continued for hours. The yield was 237 g.
• acceptable tin-plating is meant the deposition of an integral semibright tin coating which, on flow-melting, gives a bright tin-plate free from pin holes or orange-peeling and of good adhesion.
• the product was heated under reflux for two hours. It was then cooled and diluted to 65% with water.
• a plating solution for a continuous plating machine was then made up by dissolving the following ingredients in water:
• the sulphonated product was then heated for six hours at 135 C. in the following consecutive stages:
• sulphonated product is heated at a temperature of [from about to 7.
• An aqueous acidic tin-plating bath comprising a source of tin for electroplating and an additive, in an amount sufl'icient to give a bright tin electrodeposit, produced by the steps of (1) sulphonating a phenolic starting material selected from the group consisting of phenol, cresols and mixtures thereof and (2) heating the resulting sulphonated product for at least one hour, without adding further phenol or cresol, at a pressure of from 5 to 25 mm. Hg and at a temperature within the range of 120 to C.
• a tin-plating bath according to claim 8 in which the oleum is present in an excess of about 10 to 30 percent by weight above the amount stoichiometrically required in the sulphonating to the respective sulphonic acid, calculated on the weight of the phenolic starting material.

Landscapes

• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Phenolic Resins Or Amino Resins (AREA)
• Electroplating And Plating Baths Therefor (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=10016345

Family Applications (1)

Country Status (6)

Citations (4)

• 0
  • GB GB1033662D patent/GB1033662A/en active Active
  • BE BE630620D patent/BE630620A/xx unknown
  • DE DENDAT1251613D patent/DE1251613C2/de not_active Expired
• 1963
  • 1963-03-27 CH CH385863A patent/CH439908A/de unknown
  • 1963-04-04 SE SE3757/63A patent/SE305102B/xx unknown
• 1967
  • 1967-05-31 US US642305A patent/US3404075A/en not_active Expired - Lifetime

Patent Citations (4)

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