DE2224783C2 - Use of a mixture formed by the reaction of acetylenediol with an oxirane compound as a brightener and leveler for galvanic nickel baths - Google Patents

Description

The invention relates to the use of a compound obtained by reacting acetylenediol with an oxirane compound formed mixture as a brightener and leveler for galvanic nickel baths.

It is known that it is beneficial to galvanic Nickel-plating baths add small amounts of certain organic compounds, which improve the shine and the Improve the evenness of the coating. A glossy coating is one that has a good SLR results, while a uniform coating means that the irregular surfaces in the surface of workpieces, that result from production by casting, pressing, cutting and grinding, or else fine cracks and grooves left by the treatment with abrasives, filled in and on these Catfish at least for the most part on the hitherto rough one Surface to be eliminated. The fact of whether a new chemical is a leveling off of surfaces caused during electroplating and / or leads to a high-gloss coating, cannot be used Certainty can be predicted from their chemical structure.

Known chemicals suitable for the said purpose are unsaturated compounds, in particular compounds of acetylene. Since these acetylene compounds have to be dissolved in aqueous plating baths, water solubility is one of the desired properties

properties of these substances.

For this reason, these compounds generally have one or more solubility in water beneficiary group, such as B. hydroxyl, alkoxy, carboxy or sulfoxy groups. Albeit these groups Their type and their position on the molecule can essentially promote solubility in water the properties of the resulting nickel plating solutions influence.

ίο Acetylene alcohols were the first acetylene compounds, which have been proposed for the said purpose.

It has now been found that a reaction of 1 mol of acetylenediol with 0.5 to 0.95 mol of an oxirane compound formed from unreacted acetylenediol and mono- and dl-substituted reaction products Existing mixture used particularly effectively as a brightener and leveler in galvanic nickel baths can be.

Advantageous further developments of the invention are described in subclaims 2 to 7.

The reasons for the particular effectiveness of such Mixtures will be presented later. Reaction products contained in the mixture wi. z. B. monoethoxy, Diäihoxy-, Monopropoxy-, Dipn aoxy, Mofiobutoxy-, Dibutoxy and with higher mono- and dialkoxy groups substituted bytin-, pentyn- and ί iexindiols, as a result the alcohol groups on either side of the acetylene bond are all more or less suitable to even out coatings and to contribute to the creation of a high gloss of the same.

The invention will first be explained in more detail with reference to the accompanying drawing, wherein
Fig. 1 is a graphic representation which indicates in percent by weight the amounts of. "! - Butyne-M-Diol (BD), Monopropoxy-butyn-dol (MPB) and Dipropoxy-butyn-dol (DPB), which through the reaction mixture Reaction of various molar amounts of propylene oxide with 1 mol of 2-butyne-1,4-diol were obtained.

F i g. 2 shows a graphic representation of the leveling of surfaces achieved - measured in % - by BD, MPB and DPB - always in the presence of a 1.5 g / l sodium agarate solution.

Fig. 1 shows that when 1 mole of propylene oxide reacts with 1 mole of BD - after the propylene oxide has reacted - the resulting mixture is 15% by weight Contains unreacted BD, 48% by weight MPB and 37% by weight DPB. If 3/4 mole of a propylene oxide with 1 Mol BD has been implemented, so contains the appropriate Mixture 26% by weight unreacted BD, 50% by weight MPB and 24% DPB. If 1/2 mole of propylene oxide is reacted with 1 mole of BD, the result is a mixture of 43% unreacted BD. 46% MPB and 11% DPB.

Fig. 1 also shows that if less than 1 mole of propylene oxide is used, significantly less DPB is formed while the influence on the amount of MPB formed is very small. Appropriate Results are obtained when other acetylenediols are reacted with other oxyrans.

The two compounds MPB and DPB were obtained by fractional distillation of the reaction mixture isolated from 2-butin-1,4-diol and propylene oxide and subjected to proton-magnetic resonance analysis.

The plating tests were carried out with typical milk plating solutions carried out, to which NMR pure MPB and pure DPB were added, which from the Reaction mixture through multiple fractionated distillation

lation had been separated. These materials arrived either on its own or in mixtures of different compositions for use.

In Fig. 2 are the results of the planarization of the surfaces made using these individual compounds were plotted against their concentrations in the nickel plating solution. In all cases saccharin was present at a concentration of 1.5 g / l. As can be seen from Fig. 2, the two connections are MEB and DPB always as surface versions smoothing agent effective, with DPB having a considerable passivation in a certain area in proportion low concentrations of 0.04 g / l. Similar adverse effects caused by Spots from black nickel plating or from total Failure of nickel plating to appear in areas of low current density does not indicate this MPB before this is not available in a concentration of 0.4 g / l. It follows that minor changes in the concentration of DPB (namely 0.01 g / l) seriously overcomes the quality of the electroplated layers Ritzes, notches and other parts of the objects that are only exposed to relatively low current densities are, while with MPB in the concentration range of 0.1 to 0.4 g / I concentration fluctuations have little effect on the quality of the nickel coatings.

Fig. 2 also shows that BD has a maximum leveling limit a little below 60 feet. This corresponds roughly to the best result that has been achieved so far for surface- X) uniformly acting compounds. In contrast, z. B. with MPB in the mixture according to the invention a leveling effect of even more than 70% is achieved. In addition, as will be explained in detail later, the said maximum of 60% is achieved with a concentration of only 0.05 g / l, while passivation does not occur before a BD concentration of 0.5 g / l.

About the results obtained according to FIGS. 1 and 2 In addition, experiments were carried out, · »<> to determine the effect of different mixtures of MPB and DPB. These attempts were made in a Hull cell carried out that with the usual nickel plating solution with 1.5 g / l sodium sacharinate and o-mercaptobenzoic acid (MBA) as depolarization agents was filled. The results are given in the table below.

The Hull cell used was a standard cell made from a commercially available acrylic resin. Immediately below the cathode a tube with holes leading upwards was installed, through which air was passed, so that the solution through the air, particularly in the vicinity of the Cathode, was stirred.

A description of a technical. Nickel plating line and information on the composition of the baths and a description of the working conditions for them Processes that are also suitable for the application of the mixtures according to the invention are described in Chapter 5 of the book "Nickel Plating" by R. Brugger, published in 1970 by Robert Draper Ltd. Teddington, included.

The surface roughness will be before and after plating carried out by measuring the surface with a commercially available surface analyzer, which the vertical movements of a pen are recorded by measuring, d ~ r over a standard length over the surface to be led. The surface quality is determined by the number of deviations of the pen from a straight line Center line determined. The deviations are referred to below with C.L.A. marked. The initial value for C.L.A. a ground steel test plate was 1 μm, and a protective layer of 25 μm was applied to the steel plate galvanically deposited and the final value for C.L.A. then determined. The percentage of leveling the surface area was determined using the following formula:

Percentage leveling = initial C.L.A. - End C.L.A.

Initial CL.A.

Tabel

Effect of MPB, DPB and MBA on gloss and surface smoothness

DPB

DPB / MBA

MPB MPB / MBA DPB / MPB DPB / MPB / MBA

0.025
36
15th

0.025 / 0.01
32

0.025 0.025 / 0.01 0.05 / 0.05 0.05 / 0.05 / 0.01

23

53
0

C. 0.05 0.05 / 0.01 Ο, ΟΓ 0.05 / 0.01 0 L. 55 50 40 37 65 P. 35 10 0 0 35 C. 0.10 0.1 / 0.03 0.10 0.10 / 0.01 0 L. 75 60 60 58 73 P. 60 10 0 0 35 C. 0.15 0.15 / 0.03 0.15 0.20 / 0.01 0 L. distinct Bumps 65 65 63 Ugliness P. 85 75 0 0 15th

0.05 / 0.075 0.05 / 0.075 / 0.02
60
0

0.05 / 0.10 0.05 / 0.10 / 0.03
68
0

0.03 / 0.10 0.03 / 0.10 / 0.03
59

continuation

Effect of MPB, DPB and MBA on gloss and surface smoothness

DPB

DPB / MBA

MPB MPB / MBA DPB / MPB DPB / MPB / MBA

C 0.25 0.25 / 0.05 0.25

L distinct distinct 75

Bumps bumps

P 85 85 10

0.25 / 0.02 0.03 / 0.12 0.03 / 0.12 / 0.03
72 67 62

15th

C = concentration in g / l
L = degree of leveling in%

P = Degree of passivity as a percentage of the length of the test panel measured from the end of the electric field, which has the lower current density (current strength = 1 x A)

It can be clearly seen from the table above that MPB is not itself to any discernible extent leads to passivation at high concentrations. In contrast, the DPB up to the 0.04 g / l limit Is obviously a more effective leveler than the MPB in terms of weight. may not necessarily be an advantage in that be seen, as it is difficult under normal working conditions to obtain low concentrations of the agents, that ensure shine and an even surface.

Some of the following examples reveal the advantages of adding agents that have an anti-deposition effect, how they z. B. in GB-PS 9 20 922 are shown. The o-mercaptobenzoic acid (MBA) was chosen. A reduction in passivation by the DPB in the Range of higher concentrations detected. Also mixtures containing MPB / DPB with high proportions DPB can be compared with those experiments that were carried out in the absence of MBA.

From Fig. 1 it can be seen that the relative weight ratios of MPB to DBP within the limits of the preferred molar ratios of 0.5: 1 to 0.95: 1 des Alkylenoxyds to acetylenediol are about like 4: 1 to 1.5: 1. therefore a weight ratio MPB: DPB of about 2: 1, which is the preferred molar ratio for the reaction of 0.8: 1.

The table gives 5 examples of MPB / DPB mixtures formed from pure comparison products with a 1: 1 weight ratio. 1.5: 1, 2: 1, 3.3: 1 and 4: 1.

The result ^;, with or without the addition of MBA as Depolarizer obtained show the advantageous effect of mixtures prepared according to the invention became. This resulted in a sufficiently high proportion of MPB without an excess of DPB, which could cause passivation. It was also found that the Effects of MPB and DPB with regard to their leveling of the plated surfaces and the gloss effect the same sum, which has the consequence for practical application. that either is the addition of a depolarizer? to compensate for the passivation or the addition of larger amounts of additives for one Allows predetermined amount of depolarizing agent, so that the susceptibility of the electroplating process is reduced.

Flg. 1 also shows that the reaction of about 0.8 moles of propylene oxide with a 1 mole of BD results in a Mixture leads to a maximum yield of MPB with relatively low proportions of DPB at the same time and unresponsive BD makes. For the plating solution it is, in fact, better that in the mixture by reacting higher amounts of propylene oxide with ΒΠ contain somewhat larger amounts of harmful BD are instead of larger amounts of the more concentration rings DPB.

The following examples are based on propylene oxide and ÖD as the starting material. especially because of this the preferred reactants because of their availability and their mutual reactivity are. Other acetylenediols (Table 1 below) and oxiranes (Table 2 below) are included In appropriate catfish and can therefore equally to be used.

Table I - Acetylenediols

2-Βϋίίη-ί, 4-ίί! Ο!

2-pentyne-1,4-diol

3-hexyne-2.5-diol

2,5-D! Methyl-3-hexane-2,5-dol

2,4-hexadiln-1,6-dlol

4.7-dimethyl-5-decln-4,7-d! Ol

Table 2 - Oxiranes

Epoxy ethane (ethylene oxide)

1,2-epoxy propane (propylene oxide)

1,2-epoxy-butane (butylene oxide)

2,3-epoxy butane

1 -Chlor-2.3-epoxypropane (epichlorohydrin)

1 -Butoxy-2,3-e? Oxypropr.n

1 -Ally loxy-2,3-epoxypropane

The reaction between the acetylenediol and the oxirane is promoted by an inorganic or organic base, e.g. B. by sodium or potassium hydroxide. Sodium or potassium carbonate or amines such as. B. Trimethylamines. The selection of the catalyst is understandably dependent on its action on the reaction components, furthermore on the desired reaction rate and the solubility of the catalyst in the reaction components and in the final solution, if it is carried out in a solvent.
In some cases e.g. B., if the acetylenediol is a liquid, the reaction can be carried out without adding a solvent. In general, however, a solvent is required which should be as inert as possible. B. with aliphatic ethers

ζ. B. the Dl-isopropyl ether or heterocyclic compounds such. B. the Dloxan or tetrahydrofuran or an aromatic solvent such as. B. Toluene is the case. The latter type of solvent is theoretical seen the best, since such solvents do not react with the oxiranes. Also water or alcohols z. B. methanol can serve as a solvent, especially since side reactions of these compounds with the oxirane only η »run off to a minor extent and the connections formed thereby do not adversely affect the zinc plating process.

The Urterschled derives from the above GB-PS 8 64 287 and 9 70 269.

GB-PS 8 64 287 relates to reaction products obtainable from acetylene alcohols including diols and an epoxide using an epoxide / alcohol ratio of 1: 1 to 20: 1. It is obvious that these products are more or less polymers. Incidentally, more details are! ^v only on reactions described to acetylene at least 2 moles of epoxy. However, no monosubstituted compounds of the type according to the aforesaid reaction products are disclosed, quite apart from the fact that these cannot be produced at all by any of the routes described in said patent.

The GB-PS 9 70 269 discloses mono- and dlalkoxylerte compounds and in particular z. B. the connection:

HOCHjC = C CHiOCH ₁ CH • (CH ₁ ) OH

However, the individual links in this regard always come together with allyl sulfonic acid Use.

Incidentally, the type of the aforementioned reaction mixture and its possible compositions is also not mentioned in this patent specification.

DE-OS 20 05 795 discloses, as an additive to electroplating baths, a mixture of acetylenic compounds consisting of a condensate mixture and consist of an acetylenic alcohol, whereby due to the chosen proportion in addition to high molecular weight condensates with high alkylene oxide antellen also di-substituted compounds, in particular 2-butin-1,4-diol, are formed, while the aforementioned reaction products are preferably monosubstituted Contain compounds and should be easier to manufacture.

Of the mixture, the electroplating bath is preferably from 0.001 to 2.0 g / l, in particular from 0.01 to 0.4 g / l added.

In the examples below, some of the various contemplated are cooperative Plating solutions containing additives of improved effectiveness in terms of gloss and the Flexibility of the nickel plating is also listed. However, it is important that in the plating baths more than 100 g / l of nickel sulfate, nickel chloride or Nickel sulfamate or a mixture of 2 or 3 of these salts are introduced, provided that their solubility limit is not exceeded.

Some plating solutions, with the help of which particularly shiny and flexible nickel coatings are obtained, the interacting additives in dissolved form Form are the following:

Nickel sulfate

Example! ! (Ni SO ₄ ■ 6H ₂ O)

Nlckelchlorld (Nl Cl, 6H ■ ₁ O) 40 g / l Boric acid (H ₁ BO)) 40 g / l

Sodium-o-benzoylsulphide (sodium sacharlnate) 2.0 g / l o-mercaptobenzoic acid 0.02 g / l

s reaction mixture of one mole of 2-Butln-1,4-dlol and 0.85 mol of propylene oxide 0.15 g / l

Example 2

ίο Nickel sulphate (Nl SO ₄ -6H ₂ O) 300 g / l

Nickel chloride (Nl Cl, · 6H ₁ O) 40 g / l

Boric acid (HjBOj) 40 g / l sodium o-benzoyl sulphide (sodium sacharlnate) 1.5 g / l

Sodium allyl sulfonate 0.20 g / l

Dlthlodlmalelic acid 0.01 g / l reaction mixture of 1 mol of 2-butyne-1,4-dlol

and 0.75 moles of propylene oxide, 0.20 g / l

Example 3 Oil sulfate (NI SO ₄ · 6H ₁ O) 300 g / l Nlckelchlorld (NI Cl, · 6H ₁ O) 40 g / l

Boric acid (HiBO,) 40 g / l sodium o-benzoyl sulphide (sodium sacharlnate) 1.0 g / l

Sodium allyl sulfonate 1.0 g / l

o-mercaptobenzoic acid 0.01 g / l reaction mixture of 1 mol of 2-butyl-1,4-dlol

and 0.8 moles of butylene oxide 0.15 g / l

Example 4 Oil sulfate (NI SO ₄ · 6H ₁ O) 400 g / l Sodium chloride 20 g / l Boric acid (H, BO ₁ ) 50 g / l

Sodium-o-benzoyl-sulfimide (sodium sacharlnate) 1.5 g / l Reaction mixture of 1 mol of 2-butyne-1,4-dlol and 0.6 moles of chlorohydrin, 0.10 g / lc

Example 5 Nickel sulfate (NI SO ₄ · 6H, O) 100 g / l Nickel chloride (Nl Cl ₁ · 6H ₂ O) 200 g / l

Boric acid (H ₁ BO ₁ ) 40 g / l sodium o-benzoyl sulfimide (sodium sacharinate) 3.0 g / l

o-mercaptobenzoic acid 0.02 g / l reaction mixture of 1 mol of 3-hexin-2,4-dloI

and 0.8 mol of propylene oxide 0.15 g / l

Example 6 Nickel sulfate (Ni SO ₄ · 6H ₂ O) 100 g / l Nickel chloride (Ni Cl ₁ · 6H ₂ O) 200 g / l

Boric acid (H ₁ BO,) 40 g / l sodium o-benzoyl sulphide (sodium sacharlnate) 2.5 g / l

o-mercaptobenzoic acid 0.02 g / l

Sodium allylsulfonate 0.20 g / l reaction mixture of 1 mol of 2-butin-1,4-diol

and 0.8 mol of ethylene oxide, 0.20 g / l

Example 7

300 g / l

Nickel sulfate (NiSO ₄ -OH ₂ O) 100 g / l Nickel chloride (Ni Cl ₂ - 6H ₂ O) 200 g / l

Boric acid (H) BO ₁ ) 40 g / l sodium-o-benzoylsulfimld (sodium sacharinate) 2.0 g / l

Sodium allyl sulfonate 1.0 g / l

Thiodipropionic acid 0.01 g / l reaction mixture of 1 mol 2-Butln-i, 4-dioi

and 0.75 mol propylene oxide 0.15 g / l

Nucleus sulfamate Nickel chloride

Boric acid

Example 8

(Nl [SOiNH ₁ WH ₁ O)

(NICI ₂ -OH ₁ O)

(H ₁ BO ₁ )

400

50

g / l g / l g / l

Naphthalene-1,3,6-trlsulfonic acid (sodium salt) 12 g / l

Sodium 2-ethylhexyl sulfate 0.5 g / l Reaction mixture from 1 mol of 2-butyl-1,4-dol

and 0.09 mol of butyl glycldyl ether 0.05 g / l

For this purpose 2 sheets of drawings

Claims (7)

Patent claims: 1. Use of a compound obtained by reacting 1 mole of acetylenedol with 0.5 to 0.95 moles of an oxyran compound formed from unreacted acetylenediol and mono- and dl-substituted reaction products existing mixture as a brightener and leveler in galvanic nickel baths. 2. Embodiment according to claim 1, characterized in that the acetylenediol is 2-butyne-l, 4-diol; 2-pentyne-1,4-diol; 2-hexyne-1,5-dol; 2,5-methyl-3-hexyne-2,5-diol; 2,4-hexadine-1,6-diol and / or 4,7-dimethyl-5-decyne-4,7-diol is used. 3. Embodiment according to claim 1, characterized in that the oxirane compound is ethylene oxide; Propylene oxide; 1,2-epoxybutane; 2,3-epoxbutane; 1-chloro-2,3-epoxypropane; 1-butoxy-2,3-epoxy propane; 1-phenyl-1, 2-epoxyethane and / or '1-allyloxy-2,3-epoxypropai is used. 4. Ausfüjrrungsform according to claims 1 to 3, characterized in that the reaction is catalyzed by an inorganic base. 5. Embodiment according to claims 1 to 4, characterized in that the mixture is additionally an inert solvent is added. 6. embodiment according to cen claims 1 to 5, characterized in that the mixture is in a saccharin and / or a depolarizing agent which is soluble in the mixture containing nickel bath is used. 7. Embodiment according to claims 1 to 6, characterized in that the mixture in one dat Sulfenic acid derivatives and / or a thiocarboxylic acid or one or more of their water-soluble salts and optionally a nickel bath containing a wetting agent and a buffer is used.