DE2159670C2 - Galvanic nickel bath - Google Patents

Description

N ^ CH = CH,

R-

(I)

ill)

CH = CH,

CH = CH,

i "R

(III)

in which R is hydrogen or an alkyl radical with 1 to 3 carbon atoms and η 0 or an integer from 1 to 3, where> polymers to be quaternized are cir. Has a molecular weight of 5,000 to 100,000.

2. Bath according to claim 1, characterized in that it contains a polymer which is used as a monomer 2-methyl-5-vinylpyridine, 2-ethyl-5-vinylpyridine, 2-propyl-5-vinylpyridine, ^ -vinylpyridine, l-vinyl-2-methylpyridine, l-vinyl-2-ethylpyridine or contains 1-vinyl-2-propylpyridine.

3. Bath according to claim 1, characterized in that it contains a polymer which is used as a monomer I-vinylquinoline. l-vinyl-2-methylquinoline, 1-vinyl-2-ethylquinoline, 1-vinyl-2-propylquinoline, l-vinyl-5-methylquinoline, l-vinyl-5-ethylquinoline or contains 1-vinyl-5-propylquinoline.

4. Bath according to claim 1, characterized in that it contains a polymer which is used as a monomer 2-dimethylaminostyrene, 2-diethyIaminoftyrene, 2-dipropylaminostyrene or dimethylaminopropylstyrene contains.

5. 3ad according to claim 1 to 4, characterized in that it is the quaternized polymer in in an amount of 0.01 to 0.5 g / l.

6. Bath according to claim 5, characterized in that it is the quaternized polymer in one Contains an amount of 0.05 to 0.3 g / l.

60

The invention relates to a galvanic, polymer-containing nickel bath for depositing corrosion-resistant Layers with a subsequent chrome plating. Thereby coatings are produced, which have a high resistance to corrosion.

Various methods have heretofore been proposed to make metals coated with nickel and chromium, for example steel, copper. Zinc, aluminum. Magnesium and its alloys, which prevent corrosion are exposed to impart improved corrosion resistance. Furthermore, with coated plastic objects, which are now largely considered different parts in the electronics and automotive industries are used, attempts have been made to improve the anti-corrosion properties of the coated items to improve, as there is corrosion or verdigris in the underlying on the Carrier material applied copper layer is produced, although the substrate is plastic material per se is free from corrosion.

To improve the anti-corrosive properties tan already has an object to be coated with a metal layer with a; _i semi-gloss coating containing less than 0.005% sulfur and then the obtained article with a Gloss coating to form a coating having a sulfur content of about 0.02 to 0.07%. Another known method is a nickel layer with a high sulfur content from 0.1 to 0.3% between the semi-gloss coating below and the upper one in the above-mentioned Process trained gloss coating attached. Although these procedures are high To ensure corrosion resistance, chrome plating must be skillful in order to form a top layer are carried out when satisfactorily high corrosion-resistant properties are achieved should. For this purpose, addition of a selenium compound or a fluoride to the chrome plating bath is recommended provided to deposit a micro-cracked chrome coating. It is also known a bright nickel-plated object with a nickel-plating layer of about 1 to 3 μ on a bright nickel coating made before the above chrome plating using a nickel plating bath, in which an insoluble fine powder e.g. B. of silicon dioxide. Barium sulfate, iron (II) cyanides, etc. dispersed is to co-deposit the insoluble powder on the initial coating along with nickel.

However, these methods have in their practice limits on because of the limited Uberzugsverfahren and difficult operations and · erfordc for the operation loaned high skill. For example, in the case of micro-chrome plating, the temperature and current density used are limited to a narrow range, and the amount of additives is also limited to a narrow range if the cracks are to be obtained with uniformity. In addition, the microcracked chrome plating requires a period of 8 to 10 minutes with the application of an average current of 30 amps / dm ² , while conventional chrome plating can generally be performed satisfactorily in 1 to 3 minutes under the same conditions. The nickel plating processes using a dispersion of insoluble fine particles are also disadvantageous in that the current density range is limited and the stirring of the bath requires great skill. Further, when the amount of fine particles co-deposited with nickel is small, the corrosion resistance is markedly deteriorated.

The main object of the invention is to achieve this associated with the conventional methods To eliminate disadvantages and a galvanic nickel

3 4

Provide a bath with metal coatings of high grain sizes (I) to (III) with other vinyl monomers, corrosion resistance using simple special features with acrylonitrile. The mixed polymers can be produced with driving. Vinyl monomers should be at least 10 weight per die Invention relates to a galvanic, polymer zent, preferably at least 50 percent by weight, containing nickel bath for the deposition of corrosion 5 contain at least one of the monomers (I) to (III), more stable layers with subsequent processing. The polymers to be used according to the invention chroming, which is characterized by the fact that it generally exhibits an average mole bath a quaternized polymer of at least a kular weight of 5,000 to 100,000. Preferably a monomer of the general formulas should have a relative viscosity in a 1 weight-

lo percent dimethyl formamide solution from 0.1 to 0.85 at 25 ° C.

R — τ J U) The polymers themselves are not water-soluble,

^ but become water-soluble by quaternization

makes, which is carried out in the usual way. When

\ 15 Quaternizing agents are used, for example:

o_L · | j ι ({η thylsulfat. Dimethylsulfat, Ethylsulfat, Diiithylsulfat,

C Λ r \ allyl halide, alkyl halide or propane sultone.

N PH = CH ^ ^ie Q i ^{ualernis chan} g is carried out under generally

² reflux conditions in a solvent. The solvents used include e.g. B. lower

² D alcohols (methanol, ethanol, 2-propanol). Ketones

Ä / (acetone, methyl ethyl ketone) and hydrocarbons

r "^ T j xj <jm (benzene, toluene). The solvents are used alone

- "\ or used in a mixture with each other. By the

^V 25 quaternization makes the polymer water-soluble. It is preferred 10 to 100% especially

in which R is hydrogen or an alkyl radical with 1 to at least 30% of the nitrogen atoms in the pyridine or 3 carbon atoms and η 0 or an integer from 1 to 3 quinol ring or the amino group within the, wherein d ^ s to be quaternized polymers Quaternize polymer molecules.
Has a molecular weight of 5000 to 100,000, 30 The electroplating is carried out under conditions which generally lead to bright nickel plating. It has been found that. if the gloss nickel plating are used, the bath according to the invention being carried out in the presence of the above-mentioned specific water-soluble polymer using a customary gloss nickel plating-soluble polymer and the bathing which contains the above-mentioned added water-soluble final chrome plating in the usual way, quaternized polymers, is used. That is done, a corrosion-resistant coating of quaternized polymers is formed in the usual nickel bath. When using the invention preferably in an amount * of about 0.01 to 0.5 g / l. The metal coating is added to the bath, most preferably from 0.05 to 0.3 g / l. The same conditions are applied as in the case of the preparation of the electroplating bath, the same conventional bright nickel plating, without the application 40 as with the usual seduction. For example, that of a specific technique and a specific pre-set composition is commonly used. used:
The monomers, which according to the invention a nickel sulfate 150 to 350 g / l

Formulated polymers have the above formulas nickel chloride '. ".'.". '.'. 100 to 400 g / l

(1) to (III). Examples of the above monomer (I) 45 boric acid 20 to 90 g / l
are: 2-methyl-5-vinylpyridine, 2-ethyl-5-vinylpyridine,

2 - propyl - 5 - vinylpyridine, β - vinylpyridine, 1-vinyl- The nickel bath can also be used as in usual procedures

2-methyl pyridine, 1 - vinyl-2-ethylpyridine, 1-vinyl ren a primary and a secondary gloss agent are

2-propylpyridine and the like Of these, 2-methyl is hold. As the primary brightener, any

5-vinylpyridine is particularly preferred. The above mono- 50 known brightening agent, e.g. sulfonic acids, such as naphtha

mers (II) includes e.g. B. 1-vinylquinoline, l-vinyl-2-methalin sulfonic acid. Saccharin and the like and sulfamide

ethylquinoline, l-vinyl-2-ethylquinoline, l-vinyl-2-pro-derivatives, are used. Examples of secondary gloss

pylquinoline, l-vinyl-5-ynethylquinoline, l-vinyl-5-ethylquinoline are known gloss agents, e.g. 2-butyne

quinoline, l-vinyl-5-propylquinoline and the like, whereby 1-Vi- 1,4-ethanediol, propargyl alcohol, 2-butynoxyl-1,4-di-

nylquinoline is particularly preferred. Examples of 55 ethane disulphonic acid, ester of 2-butyne-l, 4-diol with

The above monomers (III) are 2-dimethylaminostyrene, sulfuric acid and the like. like., acetylene compounds

2-diethylaminostyrene, 7, -dipropylaminostyrene, dicyanohydrin, succinic acid, cyanoethylthiohydantoin,

methylaminopropylstyrene and the like, whereby 2-dimethyl bis (/ * - cyanoethyl) sulfone and similar nitrile compounds

aminostyro! is particularly preferred. gene and N-allyl quinalidinium bromide, ethylene-bis-

According to the invention to be used water 60 [N-aIlyl (4) formylpyridinium (2) bromide], pyridinium

soluble quaternized polymers are made by N-propane-o-sulfonic acid, pyridinium methyl sulfate and

Quaternization of the polymers of the above mono-like quaternary ammonium salts. The amount of

mers (I) to (III) prepared to the polymers used primary and secondary brighteners

To give water solubility. The polymers of the varies over a wide range, but is preferred

Monomers (I) to (III) include homopolymers of 65 added, the primary brighteners in an amount of

respective monomers (I) to (III), mixed polymers 0.5 to 3 g / l and the secondary brighteners in one

of at least two of the monomers (I) to (III) and an amount of 0.05 to 0.2 g / l to be used.

Mixed polymers of at least one of the mono- The objects to be electroplated include various

various products made from metals, such as iron, copper. Brass, etc., and from resins such as acrylonitrile-butadiene-styrene copolymers, Acrylonitrile-Styrofoam copolymers, polycarbonate, polyamide, polypropylene, Polystyrene, etc. are made.

The bright nickel plating is done in a conventional manner, e.g. B. at a current density of 1 to 10 Amp./dm ² , at a temperature of 45 to 60 ° C, while the system is moved with air.

The one coated with the present bright nickel plating The item is then subjected to conventional chrome plating, creating an electroplating layer is formed with excellent corrosion resistance on the obtained article. For the Chrome plating will use a standard chrome bath. One of the preferred examples of the bath is as follows:

Chiomic anhydride 250 g / l

Sulfuric acid 2.5 g / i

Trivalent Cr ion 3 g / I

The chrome plating is z. B. carried out at a current density of 20 Amp. Dm ² for 1 to 3 minutes

The following examples serve to illustrate the invention.

example 1

Production of the quaternized polymer
300 g of 2-methyl-5-vinylpyridine were mixed with 750 ml of water containing 0.5 percent by weight of starch, and the mixture was heated to 55 ° C. with stirring. At this temperature, 100 ml of 10 percent by weight aqueous K ₂ S ₂ O _g Solution was added dropwise to the mixture, after which the system was heated at 80 ° C. for 4 hours with stirring, yielding polymer of 2-methyl-5-vinylpyridine having an average molecular weight of 20,000 to 30,000 and a relative viscosity of 0.3 until 0 85 was formed in 1 percent strength by weight dimethylformamide solution at 25 ° C.

To 20 g of the obtained dissolved in 150 ml of water, polymers were 20 g of allyl bromide was added and the mixture was heated for 3 hours at 40 to 50 ³ C, whereby water-soluble quaternized polymer was obtained in the form of aqueous solution.

Electroplating on a steel plate

A steel plate of 0.8 × 50 × 100 mm was immersed in the following bath for semi-bright nickel plating at a current density of 3 amp./dm ² at 50 ° C. to produce a semi-bright nickel coating of 14 μm thick.

Semi-gloss nickel plating bath used

Nickel sulfate 300 g / l

Nickel chloride 50 g / l

Boric acid 40 g / l

37 weight percent

Formalin 0.4 ml / 1

Coumarin 0.05 g / l

Lauryl sulfate - 0.005 g / l

Water, necessary amount for

Making 1 1 bath

Used gloss nickel-plating bath

Nickel sulphate 240 g / l

Nickel chloride 45 g / l

Boric acid 40 g / l

Sodium naphtha sulphonate 0.5 g / l

Saccharin 1.5 g / l

Butynediol 0.1 g / l

quaternary obtained above

nized polymer 0.1 g / l

Water, necessary amount for

Making 1 1 bath

The thus treated plate was thereafter subjected to chrome plating in the following chrome bath at a current density of 20 AMPT / dm ² immersed for 1 minute at 50 ⁰ C, to produce a chromium coating of 0.25 μ thickness.

Chromium plating bath used

Chromic anhydride 250 g 1

Sulfuric acid 2.5 g 1

Trivalent chromium ion 2.0 g!

The plate obtained was subjected to the following tests:

1. Cass test, carried out in accordance with JIS DO 20 !.

2. Corrodekote test. executed according to
JIS DO 201.

3. EC test, carried out according to »galvanization«. Vol. 53, No. 9, 1124 (19661.

The corrosion tests carried out are described below:

1. Cass test

It is an aqueous salt solution of pure sodium chloride in ion-exchanged water with a concentration of 5 ± 1 percent by weight. 0.26 g of copper (II) chloride are added to 1 liter of this solution and a small amount of acetic acid was added to adjust the pH to 3.0 to 3.1 at 25 ° C. The samples to be tested are placed in a specific position in the spray chamber of the test device and the above aqueous salt solution for 16 hours under a pressure of 1 ± 0.1 kg / cm sprayed at 49 ± 2 ° C. This process represents a cycle.

The corrosion of the treated test sample is indicated by the rating number in the following Table, which is determined with the naked eye. The rating number 10 means that the examined Sample shows no corrosion.

table

6o

The steel plate thereby obtained was then dm in the present invention, given below gloss nickel plating bath at a current density of 3 Amp./ ² and 50 ⁰ C immersed μ a bright nickel coating of 6 to manufacture.

Evaluation number Corrosion (%) less than 0.02 0.02 - less as 0.05 10 0 over 0.05 - less as 0.07 9.8 over 0.07 - less as 0.10 9.5 over 0.10 - less as 0.25 9.3 over 0.25 - less as 0.50 9 over 0.50 - less as 1.0 8th over 1.0 - less as 2.5 7th over 2.5 - less as 5.0 6th over 5.0 - less as 10 5 over 4th 3

2 159 670; 7th continuation " 8th Table III

Rating number

2 1 0

Corrosion (%)

over 10 - less than 25
over 25 - less than 50
over 50

2. Corrodekote test

Corrosion = - * §- ·
3. EC test

¹⁰ °

In the electrolytic corrosion test, a cleaned steel-based sample is placed in a with Electrolyte-filled electrolytic cell is electrolyzed and the period is determined when the iron begins to break down to be extracted as a result of electrolysis under constant potential.

The test results are given in Tables I to III below, which are also for comparison show the test results on a steel plate galvanized in the same way as above, except, that for the bright nickel plating, the bright nickel plating bath without the addition of the quaternized Polymers were used

Table I.
Cass test in evaluation numbers *)

ί 3 3 ZyI % 9 comparison
example 1
*) Value 10 9.5
10 7.5
10 1.6
0.2 Zy * 3.0
8.0 = no corrosion.
Table II
Corrosion in the
6th . 7th comparison
example 1 5.0
9.5 Jen
5 3.6
1.8 2.4
0.5 Ί _j 0.8
0

EC exam

(Period when the iron begins to dissolve as a result of electrolysis under constant potential)

Compare 120 to 180 seconds

Example 1 290 to 380 seconds

7 ml of a solution of 5 g of Cu (NO ₃ I ₂ · 3H ₂ O in 1000 ml of distilled water, 30 ml of a solution of 5 g of FeCl ₃ · 6H ₂ O in 1000 ml of distilled water and 10 ml of a A solution of 100 g of NH ₄ Cl in 1000 ml of distilled water was added and the resulting mixture was stirred to produce a paste.

This paste is applied to the surface of the test sample with a brush in a thickness of about 100 μ, and the coated sample is left in a test device at relative humidity for 16 hours of 80 to 90% and a temperature of 38 ± 2 ° C. After that, that's on the surface applied paste wiped off with a soft cloth. This process represents a cycle.

Soft and transparent plastic film is applied crosswise at right angles with a distance of 5 mm firmly adhered to the surface of the treated test sample with the formation of grids. The percentage corrosion is calculated from the number of grids that have the corrosion defect (α), and the number of grids covering the entire treated surface (5) according to the following equation calculated:

Example 2 Preparation of the quaternized polymer

1.5 g of benzoyl peroxide were added to 300 ml of water in a nitrogen gas stream, whereupon 20 g of acrylonitrile and 80 g of 2-methyl-5-vinyjpyridine were further added. The mixture was heated to 80 ° C. for 3 hours, and 20 g of polymer with an average molecular weight of 5000 to 70,000 and a relative viscosity of 0.1 to 0.7 in 1 percent strength by weight dimethylformamide solution at 25 ° C. were obtained. The obtained polymer was dissolved in ethanol and 20 g of methyl iodide was added to the solution. The mixture was heated to 40 to 50 ^° C. for 4 hours with stirring, as a result of which water-soluble quaternized polymer was obtained.

Electroplating on a steel plate

A steel plate of 0.8 x 50 x 100 mm was vcffahren in the following gloss copper plating bath at a current density of 3 Amp./dm in the periodic reversal at 50 ⁰ C immersed to a G to -? Copper plating of 15 μ thickness to produce .

Bright copper plating bath used

Copper cyanide 30 g / l

Sodium cyanide 105 g / l

Potassium hydroxide 10 g / l

Lead ion (Pb ^{4 +} ) 0.02 g / l

Water, necessary amount for
Making 1 1 bath

The resulting plate was then immersed in the following gloss nickel plating bath at a current density before 3Amp./dm ² at 50 ⁰ C to obtain a gloss nickel coating thickness of 6 μ to manufacture.

Used gloss nickel-plating bath

Nickel sulphate 240 g / l

Nickel chloride 45 g / l

Boric acid 40 g / l

Allylsulfonate 0.5 g / l

Saccharin lg / l

2-butynoxy-1,4-di (propyl-

sulfonic acid) 0.1 g / l

quaternized obtained above

Polymer 0.1 g / l

Water, necessary Meage for

Manufacture of 1! bath

Thereafter, the treated plate in the chromium plating bath was folgenc dm at a current density of 20 Amp ² at 50 ⁰ C for 1 minute dipped to a Chron coating of 0.25 μ thickness to manufacture.

Chromium plating bath used

Chromic acid 250 g / l

Sulfuric acid IS g / l

Sodium flunt 5 g / 1

Cr- I Sl

For comparison, a steel plate was electroplated in the same manner as above except that No quaternized polymer was added to the bright nickel plating bath.

The test results obtained on the galvanized steel plates are given in Tables IV below to V shown.

Table IV
Cass exam in rating numbers

Comparison.
Example 2.

Cycles

of 0.25μ prepared in the same way as in Example 1.

For comparison, the ABS resin sheet was electroplated in the same way as above except that no quaternized polymer was added to the bright nickel plating bath

The results of the tests carried out on the plates are shown in Table VI below reproduced.

Table VI
Cass test

1 ι .1 % 4th 5 15th
comparison 6.0 5.5 4.8 4.0 3.5 Example 3 10 10 9.5 9.0 8.5 Table V Corrosion in

Z \ k! Cn

5.0
10

9.0

Comparison.
Example 2.

L 2 Cycles 4th I. 10 .1 40 5 0 20th 0.5 0 0.2

-

60
1.0

Example 3

Production of the quaternized polymer
20 g of the ₀₁₀₀ ml of acetone were dissolved 2-methyl-5-vinyipyridinpoiymeren obtained in the same manner as in Example 1 _in), whereupon 20 g propane sultone was added dropwise. ^{The system was heated to 40 to 50 °} C. for 30 minutes with stirring in order to obtain water-soluble quaternized polymer.

Electroplating on ABS synthetic resin? - ¹⁵

A synthetic resin plate made of acrylonitrile-butadiene-styrene mixed polymer with dimensions of 3 × 50 × 100 mm was ^{immersed in a mixture of 400 g / l chromic acid and 460 g / l sulfuric acid at 60 °} C. for 10 minutes. The plate was then washed with water and immersed for a further 3 minutes at room temperature in a bath containing 15 g / l stannous chloride and 15 ml / l 35 weight percent hydrochloric acid. The plate was then immersed for 1 minute at room temperature in a bath which contained 0.2 g / l palladium chloride and 0.1 ml / l 37% by weight hydrochloric acid.

The synthetic resin plate obtained was immersed for 10 minutes at room temperature in an electroless copper plating bath containing 30 g / l copper sulfate, 70 g / l sodium tartar, 20 g / l sodium hydroxide and 30 m / l 37 weight percent formalin, with a copper coating of about 0.3 μ Thickness was made on the surface of the synthetic resin plate. $ ₅ The resin plate obtained wu ^r de in an acidic copper bath that 220 g / l of copper sulfate, 50 g / l sulfuric acid and 2 ml / 1 brightener enihieh, electroplated at a current density of 3 AmpVdm ² and at 25 ^C C to form a coating an average thickness of 20 μ.

The obtained ABS resin sheet became the bright nickel long in the same manner as in Example 1, but the quaternized polymer obtained above was subjected to bright nickel plating used to make a coating with an average thickness of 6μ. After that, a Chrome plating of an average thickness

Example 4

5 steel plates were each electroplated in the same manner as in Example 1 except for the following five kinds of quaternized polymers each in an amount of 0.1 g / l in the bright nickel plating bath were used.

Quaternized polymer used

(A) Quaternized polymer!? Made by quaternizing of the polymer of / 3-vinylpyridine with an average molecular weight of 10,000 to 40,000 ml of allyl brumide on the same Way as in Example 2 was prepared.

(B) Quaternized polymer obtained by quaternizing the polymer from 1-vinylquinoline with an average molecular weight of 30,000 to 40,000 with dimethyl sulfate on the same Way as in Example 2 was prepared.

(C) Quaternized polymer obtained by quaternizing of the polymer of 1-vinyl-5-propylquinoline having an average molecular weight of 30,000 to 40,000 with dimethyl sulfate in the same manner as in Example 2.

(D) Quaternized polymer obtained by quaternizing of the polymer of 2-diethylaminostyrene having an average molecular weight from 15,000 to 60,000 with allyl bromide in the same manner as in Example 1.

(E) Quaternized polymer obtained by quaternizing of the polymer from 2-dimethylaminostyro! with an average molecular weight from 10,000 to 30,000 with diethyl sulfate on the the same way as in Example 1 was prepared

The results of the Cass test carried out in the same way as in Example 1 are for each of them holding plate indicated in the following Table VII

Table VII
Cass exam

Polymer A.
Polymer B.
Polymeric C.
Polymer D.
Polymeric E.

Cycles 2 3 1 10.0 9.5 10.0 9.9 9.0 10.0 9.5 9.0 10.0 10.0 9.2 10.0 10.0 9.5 10.0

Claims (1)

Patent claims: 1. Galvanic, polymer-containing nickel bath for depositing corrosion-resistant Layers in a subsequent chrome plating, characterized in that the bath a quaternized polymer composed of at least one monomer of the general formulas