KR19990064056A - Tin Plated Electrolyte Composition - Google Patents

Abstract

mono-, di-, at least one of a) at least one acid selected from sulfuric acid, sulfamic acid, acrylic sulfonic acid, alkyl sulfonic acid and alkanol sulfonic acid, b) substituents comprising secondary, tertiary or quaternary nitrogen atoms At least one additive comprising a tri-substituted phenol (each optionally alkyloxylated) or a mixture of two or more of these compounds, c) a source of tin and d) water in a method for electroplating a surface with tin. Described are compositions suitable for use.

Description

Tin Plated Electrolyte Composition

Ideally, the electrolyte should have properties that produce a wide range of plating, produce a good layer of deposition, have low corrosiveness, good antioxidant properties, low toxicity and low environmental impact.

Many electrolyte compositions are known and are available in the art. Typical baths include aqueous acid baths based on fluoroborate and fluorosilicate electrolytes as described, for example, in US-A-3 769 182 and US-A-4 118 289. Aryl sulfonic acids have been used in electroplating baths as described, for example, in US-A-3 905 878. Traditionally, the aryl sulfonic acid selected is phenolsulfonic acid as used in the Ferrostan procedure.

Mineral acid (particularly sulfuric acid) electroplating baths have also been described. For example, US Pat. No. 2,156,2727 describes a bath containing taric acid and sulfuric acid for producing a tin coating of fine crystal textures.

Alkanesulfonic acids containing 1 to 5 carbon atoms in the alkyl group were previously used in certain electrolytic plating baths and this use was first described in US-A-2 522 942. More recently methanesulfonic acid has been formulated with a number of varnishes for use in electroplating tin, lead and tin-lead alloys, for example as in US-A-4 565 610 and US-A-4 617 097. It has been raised as a particular preferred example of alkanesulfonic acid. However, methanesulfonic acid based systems suffer from high cost, toxicity and odor problems and are known to introduce surface defects in flow polished strip steel sheets.

Various plating bath compositions are known which include alkanes or alkanol sulfonic acids (usually methane sulfonic acid), tin and / or lead salts and various auxiliary additives. Known auxiliary additives range from small organic molecules to large polymeric surfactant molecules and are US-A-4 555 314, US-A-4 565 609, US-A-4 582 576, US-A-4 599 149, US- A-4 617 097, US-A-4 666 999, US-A-4 673 470, US-A-4 701 244, US-A-4 828 657 and US-A-4 849 059. For example, plating bath compositions containing mixtures of aryl and alkyl sulfonic acids are also known in the art, as described in EP 0 490 575.

Various additives have been proposed to enhance the quality of tin plates. These include hydrophobic organic compounds and alkylene oxides such as alpha naphthol 6 mole ethoxylate ('ENSA 6' supplied by Emery-Trylon); Alkylbenzene alkoxylates such as 'Tritons'; Derivatives of N-heterocycles such as 2-alkylimidazolines; Aromatic aldehydes such as naphthalaldehyde; Derivatives of 2,2-bis (4-hydroxyphenyl) propane, for example 2,2-bis (4-hydroxyphenyl) propane, 'Diphone V' formed by reacting with sulfonating agents (supplied by Yorkshire Chemicals ); And condensates of 2,4,6-substituted phenols, wherein at least one of the substituents comprises secondary, tertiary, or quaternary nitrogen atoms as described in US-A-3 954 573. However, the latter additives are only described for use in fluoroborate tin plating systems.

In the case of strip tin plate manufacturing, it is commercially viable to have a system capable of producing a satisfactory tin deposit layer over the widest possible range of current densities to accommodate all variations in production rate and minimize the occurrence of current density defects. desirable.

The present invention relates to electrolyte compositions suitable for electroplating surfaces with tin in high speed strip or wire plating processes.

Accordingly, the present invention provides a composition suitable for use in the process of electroplating a surface with tin, which exhibits all of the above mentioned benefits of a wide range of plating, good deposition and improved environmental benefits. Such compositions comprise a) one or more acids selected from sulfuric acid, sulfamic acid, aryl sulfonic acid, alkyl sulfonic acid and alkanol sulfonic acid, b) at least one of the substituents comprising secondary, tertiary or quaternary nitrogen atoms -, Di- or tri-substituted phenols (optionally each alkoxylated) (preferably 2,4 or 2,6-disubstituted or 2,4,6-trisubstituted phenols), or mixtures of two or more thereof At least one additive, c) tin source, d) antioxidant (optional), and e) water.

Preferably the tin source is tin salt. The tin source may also be elemental tin.

The acid may be any single acid or combination of acids. Preferred examples of the acid include sulfuric acid, sulfamic acid, phenolsulfonic acid, methane sulfonic acid and toluenesulfonic acid.

The acid (s) are present at a total concentration of 25 to 500 g / l, more preferably 30 to 250 g / l, more preferably 30 to 100 g / l of the composition (relative to the composition).

The tin source is preferably present in the composition at a concentration of 5 to 100 g / l (more preferably 15 to 60 g / l) with respect to the composition. If the tin salt is a tin source, it does not need to be a salt of a monosubstituted benzenesulfonic acid or inorganic acid. Thus, the composition may contain other ions in addition to those from tin, sulfonates and inorganic acids. If the tin source is solid tin, it may be a tin anode that gradually dissolves as electrolysis proceeds to maintain a substantially constant concentration of tin ions in the electroplating bath. When the tin source is tin salt, as tin is electrodeposited from the bath, it can be metered into the electroplating bath so that tin salt is added to the bath to maintain the concentration of tin ions in the bath at a constant level.

Antioxidants may optionally be added. Such materials delay the oxidation of divalent tin to tetravalent tin, which can lead to sludge formation and loss of first tin. The preferred amount of antioxidant to be added is in the range of 1 to 50 g / l of the composition, most preferably 2.5 to 20 g / l of the composition. Typical antioxidants are described, for example, in US Pat. No. 3,749,649 and 1,2,3-trihydroxybenzene, 1,2-dihydroxybenzene, 1,2-dihydroxybenzene-4- Sulfonic acid, 1,2-dihydroxybenzene-3,5-disulfonic acid, 1,4-dihydroxybenzene, 1,4-dihydroxybenzene-2-sulfonic acid, 1,4-dihydroxybenzene -2,5-disulfonic acid or vanadium pentoxide.

The compositions of the invention also include one or more additives wherein at least one of the substituents contains mono-, di- or tri-substituted phenols, each optionally optionally alkoxylated, containing secondary, tertiary or quaternary nitrogen atoms. do. The phenol is preferably 2,4 or 2,6-disubstituted or 2,4,6-trisubstituted phenol.

The additive has the formula (1).

In the above formula,

Y is alkylene, CH ₂ CH ₂ O or CH (CH ₃ ) CH ₂ O,

n ³ is 0 to 10,

N ³ is 1 when Y is alkylene,

R is a group of formula 1a,

R ³ is H, alkyl, aryl, hydroxyl or CHO, provided that when R ³ is hydroxyl or CHO n ² is 1 to 3, and when R ³ is H, alkyl or aryl, n ² is 1 Is,

R ⁴ is H, alkyl, cycloalkyl, hydroxyalkyl or alkoxyalkyl,

R ⁵ is alkyl optionally interrupted by O or N atoms, which may be further substituted,

X is an optionally further substituted phenol (optionally alkoxylated) radical,

n is 0 or 1,

n ¹ is 1 to 7,

If n is 0, n ¹ is 1,

when n is 1, n ¹ is 1 to 7,

R may optionally be a quaternary ammonium salt formed by reaction with acids such as sulfuric acid, toluenesulfonic acid, sulfamic acid, phenolsulfonic acid and methanesulfonic acid.

R ₁ and R ₂ (which may be the same or different) are R, H or optionally substituted alkyl.

Particularly preferred examples include compounds of the formulas 2a, 2b, 2c, 2d.

In the above formula,

R ₁ is CH ₃ , CH ₂ CH ₃ CH (CH ₃ ) ₂ or C (CH ₃ ) ₃ ,

n is 1 to 7,

x is 0 to 10.

In the above formula,

R ₁ is CH ₃ CH ₂ CH ₃ , CH (CH ₃ ) ₂ or C (CH ₃ ) ₃ .

In the above formula,

R ₁ is CH ₃ , CH ₂ CH ₃ , CH (CH ₃ ) ₂ or C (CH ₃ ) ₃ ,

n is 1 to 7.

In the above formula,

R is -CH ₂ NHCH ₂ CH ₂ NHCH ₂ CH ₂ OH,

R ₁ is —CH ₃ ,, —CH ₂ CH ₃ or —C (CH ₃ ) ₃ ,

R ₂ is H or R.

As known to those skilled in the art, such additives may be conveniently prepared by condensation of phenols with aldehydes and amines under acidic or basic conditions. The molar ratio of phenol: amine: aldehyde may vary over a wide range, typically in the range 1: 1: 1 to 1: 2: 2. As will be apparent to those skilled in the art, this reaction will produce a mixture of monomer product and polymer product. The reaction product may also be alkoxylated with ethylene or propylene oxide. Any phenol, amine and aldehyde may be used, but preferred examples include the following compounds.

Phenols: Ortho and / or para alkylphenols where the alkyl groups are methyl, ethyl, isopropyl, n-butyl, sec-butyl, tert-butyl, isoamyl, hexyl, and nonyl.

Diphenol: 2,2-bis (4-hydroxyphenyl) propane or 4,4'-dihydroxydiphenylsulfone.

Aldehyde: formaldehyde, acetaldehyde, glyoxal.

Amines: methylamine, dimethylamine, ethylamine, diethylamine, n- or iso-propylamine, n- or sec-butylamine, n-hexylamine, ethanolamine, diethanolamine, n or iso-propanolamine, 2-aminobutanol, 4-aminobutanol, 2-amino-5-diethylaminopentane, 2- (2-aminoethoxy) ethanol, 2- (2-aminoethylamino) ethanol, 2-amino-2-ethyl -1,3-propanediol.

When the composition of the present invention is used for tin plating, it provides a wider plating range and a more shiny plate with fewer surface defects than can be obtained by using other additives.

Surfaces that can be tin-plated using the compositions and methods of the invention are typically surfaces that can be tin-plated, such as steel or copper.

Example 1

This example illustrates how preferred additives can be synthesized using basic catalysis.

Substituted phenol (1 mole), water (equivalent amount based on phenol) and sodium hydroxide (0.2 mole) are added to the reactor. The mixture is heated with stirring at 60 ° C. until a clear solution is obtained.

Amine (2 moles) is added to the second reactor and aldehyde (2 moles) is added slowly under stirring while maintaining a temperature of 60 ° C. or less. This solution is added to the alkylphenol solution in the first reactor and the mixture is heated at 100 ° C. for 30 minutes.

The following examples illustrate this synthesis method.

Example number phenol Amine Aldehyde 2 4-methylphenol Ethanolamine Formaldehyde 3 4-tert butylphenol 2- (2-aminoethylamino) ethanol Formaldehyde 4 4,4'-isopropylidene-diphenol Diethanolamine Formaldehyde 5 4-ethylphenol Iso-propanolamine Formaldehyde 6 4-tert butylphenol Diethanolamine Formaldehyde 7 4-tert butylphenol Ethanolamine Formaldehyde 8 3-methylphenol Ethanolamine Glyoxal 9 4-nonylphenol 7 mole ethoxylate Ethanolamine Formaldehyde 10 4-tert butylphenol 1 mole ethoxylate 2-amino-2-ethylpropanediol Formaldehyde

Example 11

This example illustrates how preferred additives can be prepared using acid catalysis.

Formaldehyde (2 moles) is slowly added to ethanolamine (2 moles) while maintaining the temperature below 60 ° C. Water (108 g) is added and the mixture is acidified to pH 3 with sulfuric acid. The mixture is heated to 60 ° C. and p-cresol (1 mole) is added. On completion of the addition the mixture is heated to 100 ° C. for 3 minutes and then cooled.

Electroplating properties of the various compositions are measured at 50 ° C. for 1 minute with a total current of 3 amps in Hull Cell. A 10 cm x 6 cm steel sheet pre-cleaned by dipping in sodium hydroxide followed by water washing and dipping in 18.5% hydrochloric acid is used in all examples below.

The aqueous compositions used are illustrated in Table 2 and Examples 12-22 are according to the present invention, while Examples 23 and 24 are provided for comparison.

In Examples 12 and 14-21 the composition comprises 1 g / l antioxidant (1,2-dihydroxybenzene-4-sulfonic acid). The tin source in all cases is the tin sulfate in the amount of 30 g / l calculated as Sn ⁺⁺ .

Example Number mountain Acid concentration (g / ℓ) Additives (per example) Additive concentration (g / ℓ) Plating range (A / dm ² ) x 10 12 Sulfuric acid 60 (4) 6 15-67 13 PSA 60 (5) 6 5.4-90 14 PTSA / sulfamic acid 10/50 Part 9 (2) + Part 1 (3) 6 6.5-90 15 PTSA / Sulfate 40/50 (11) 6 5.4-37 16 Benzene sulfonic acid 60 Part 1 (2) + Part 1 (6) 6 10-55 17 Sulfuric acid 50 (8) 6 11-82 18 Methanesulfonic acid 60 (7) 6 5.4-38 19 Methanesulfonic acid 50 (9) 3 6-58 20 PTSA / Sulfate 10/40 Part 8 (3) + Part 2 (9) 5 5.4-70 21 PTSA / Sulfate 10/50 Part 9 (2) + Part 1 (9) 6 5.4-90 22 PSA 40 10 6 11-74 23 PSA 60 ENSA 6 4 9-54 24 PSA 60 Diphone V 5 7-52 All concentrations are g / l of the composition, including water. PSA is phenol sulfonic acid. PTSA is para toluene sulfonic acid.

Claims (17)

a) at least one acid selected from sulfuric acid, sulfamic acid, aryl sulfonic acid, alkyl sulfonic acid and alkanol sulfonic acid, b) at least one of the mono-, di- or tri-substituted phenols (each optionally alkoxylated) comprising secondary, tertiary or quaternary nitrogen atoms or at least one mixture of two or more of these compounds additive, c) annotation sources, and d) a composition suitable for use in a method for electroplating a surface with tin, comprising water. The composition of claim 1 wherein the phenol is 2,4 or 2,6-disubstituted or 2,4,6-trisubstituted phenol. The composition of claim 1 or 2, wherein the tin source is tin salt. The composition of claim 1, wherein the one or more acids are selected from sulfuric acid, sulfamic acid, phenol-4-sulfonic acid, toluene 2- or 4-sulfonic acid or methanesulfonic acid. 5. The composition of claim 1, wherein the acid (s) is present at a total concentration of 25 to 500 g / l of the composition (relative to the composition). 6. The composition of claim 5 wherein the acid (s) is present at a concentration of 30 to 250 g / l. 7. The composition of claim 6 wherein the acid (s) is present at a concentration of 30 to 100 g / l. The composition of claim 1, wherein the tin source is present in the composition at a concentration of 5 to 100 g / l relative to the composition. 9. The composition of claim 8 wherein the tin source is present in an amount of 15 to 60 g / l. 10. A composition according to any one of claims 1 to 9, which further comprises an antioxidant. The composition of claim 10 wherein the antioxidant is present in an amount of 1 to 50 g / l of the composition. The composition of claim 11 wherein the antioxidant is present in an amount of 2.5 to 20 g / l of the composition. 13. The composition of any one of the preceding claims, wherein at least one additive is selected from compounds of formula (I). Formula 1 Formula 1a In the above formula, Y is alkylene, CH ₂ CH ₂ O or CH (CH ₃ ) CH ₂ O, n ³ is 0 to 10, N ³ is 1 when Y is alkylene, R is a group of formula 1a, R ³ is H, alkyl, aryl, hydroxyl or CHO, provided that when R ³ is hydroxyl or CHO n ² is 1 to 3, and when R ³ is H, alkyl or aryl, n ² is 1 Is, R ⁴ is H, alkyl, cycloalkyl, hydroxyalkyl or alkoxyalkyl, R ⁵ is alkyl optionally interrupted by O or N atoms, which may be further substituted, X is an optionally further substituted phenol (optionally alkoxylated) radical, n is 0 or 1, n ¹ is 1 to 7, If n is 0, n ¹ is 1, when n is 1, n ¹ is 1 to 7, R is a quaternary ammonium salt formed by reaction with acids such as sulfuric acid, toluenesulfonic acid, sulfamic acid, phenolsulfonic acid and methanesulfonic acid, R ₁ and R ₂ may be the same or different and are R, H or optionally further substituted alkyl. The composition of claim 13, wherein the at least one additive is selected from compounds of Formulas 1, 2c and 2d. Formula 1 Formula 1a In the above formula, Y is alkylene, CH ₂ CH ₂ O or CH (CH ₃ ) CH ₂ O, n ³ is 0 to 10, N ³ is 1 when Y is alkylene, R is a group of formula 1a. Formula 2c In the above formula, R ₁ is CH ₃ , CH ₂ CH ₃ , CH (CH ₃ ) ₂ or C (CH ₃ ) ₃ , n is 1 to 7. Formula 2d In the above formula, R is -CH ₂ NHCH ₂ CH ₂ NHCH ₂ CH ₂ OH, R ₁ is —CH ₃ ,, —CH ₂ CH ₃ or —C (CH ₃ ) ₃ , R ₂ is H or R. A method of tin plating of a surface comprising the use of a composition as claimed in claim 1. The method of claim 15, wherein the process is a strip or wire plating process. A tin-plated surface using the composition of any one of claims 1 to 14 and / or the method of claim 15 or 16.