DE2140850A1 - Process for producing a film on the surface of an object made of metal - Google Patents

Description

Method of making a film on the surface " an object made of metal

The invention relates to a method for producing a film on the surface of an object made of metal, and although by way of the deposition of a crosslinked polymer film on the surface of an electrode by the electrolytic Copolymerization of a vinyl monomer and a divinyl monomer.

It is known using electrophoretic coating processes Produce pigment and prepolymer films on the surfaces of metal electrodes. This technique has wide application found for industrial purposes. According to the known processes, however, a water-soluble prepolymer must be synthesized separately will. The prepolymer is dissolved in the water-pigment system. The prepolymer and the pigment migrate to the anode in the electric field and are deposited there. Various follow from this Disadvantage. The cost is very high, given the raw material is a water soluble prepolymer that must be cured. By using various additives, the -Complicated control of the bathroom; the efficiency related to the electrical charge is low. It is also very difficult to get a thin film.

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It has become also known that electrolytic polymerization in the way of metal surfaces can be treated in such a way that by using a H _o nomers can be brought about as a starting material at the same time, the polymerization and the formation of a film. Furthermore, it has already been possible to produce an EL polymer film directly on an electrode plate using a vinyl monomer, namely using acrylonitrile. (U. Sahara et al., "Kinzoku Hyomen Gijutsu", Vol. 20, No. 8, p. 414 (1969)). However, the authors of this process themselves admit that the PiIm produced in this way has only a low molecular weight, and that its adhesive properties, its hardness and its flexibility are also inadequate. It is therefore unsuitable for practical purposes. In addition, a crosslinked polymer film cannot be produced by the known methods.

It is accordingly the object of the present invention to provide a method for producing a pilm on the surface of a To create an object made of metal, the high molecular weight and also good adhesion properties, hardness and Has flexibility. It is also an object of the present invention to provide a method with which a more uniform PiIm can be created on the surface of an object of complex design.

It is also an object of the present invention to provide a Ver,,.> "Drive to create, with the help of which on a metal works ^ ' trode an even continuous PiIm a ^ s networked test Polymer by electrolyte! See copolymerization of vinyl monomer with divinyl monomer using direct current, which has a high molecular weight and is insoluble in the solvent used. The method should be free from the disadvantages of the known methods.

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21A0850

According to the invention, there is a method for producing a

Film on the surface of an object made of metal by means of electrolytic polymerization characterized in that dai3 a mixture of vinyl monomer, divinyl monomer, an electrolyte that increases the conductivity of the mixture, and a polar organic solvent, the object to be coated with the film as one of the electrodes used in the mixture, direct current passed through it and thus a BIm of crosslinked vinyl polymer deposited on the surface of the article.

The invention is explained below on the basis of exemplary embodiments with reference to the accompanying drawings. Show it?

1 is a schematic view in longitudinal section of the apparatus used to produce the film;

FIG. 2 shows a cross section of the apparatus according to FIG. 1.

In the method according to the invention, the electrolytic is used in the Ytege Polymerization deposited a film on the surface of an electrode. This is a mixture of one. Vinyl monomers, a divinyl monomer, one the electrical conductivity increasing electrolytes and a polar organic solvent are used. The one to be covered with a film Object is used as one of the electrodes. When passing through Direct current creates a deposit of a film from networked! Vinyl polymer on the surface of the Subject.

Suitable for carrying out the method according to the invention Vinyl monomers are the following:

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2H0850

Acrylonitrile, methacrylonitrile, methyl acrylate, ethyl acrylate, Methyl methacrylate, acrylamide, jtf-methylacrylamide, methacrylamide, Acrolein, methacrolein, 2-hydroxyethyl methacrylate, Methyl vinyl ketone, vinyl acetate, 1-cyanopropylene, ethyl vinyl

ether, allyl alcohol, Glycidylmethacrylät (an ester of 2,3-EpoxyrTropanols and methacrylic acid) Vinvltoluol otyrol 'Ot-Me thy 1 styrene and butadiene. Suitable divinyl monomers are: iJjN'-methylene-bis-acrylamide; Divinyl esters such as ethylene glycol dimethacrylate; Divinyl ether; Divinylbenzene, divinyl sulfone, 1,5-hexadiene-3-yne; Hexatrienes.

AIS electrolyte, the following substances can be used: Mckee's balz (tetraethylammonium p-toluenesulfonate), Tetraalkylaminoniumsalze; Nitrates and perchlorates of alkali metals. Polar solvents such as preferably dimethyl sulfoxide, dimethylformamide, acetonitrile, pyridine, formamide, dimethyl acetamide and nitrobenzene are used as solvents.

The process of the present invention is carried out using the apparatus shown in the drawings. Fig. 1 shows a schematic representation of this apparatus, Fig. 2 shows a cross section. Reference numerals 1 and 2 denote a jileictrode, and the ψ with the film to be coated article. The electrolytic bath 3 contains the mixture 4 of vinyl monomer and divinyl monomer. The baa is covered by a lid b . In the embodiment shown, a direct current source b is also provided.

In the production of a crosslinked polymer film, a mixture 4 is first produced, which is a mixture of monomers consisting of one or more than one vinyl monomer and one or more than one:;. Divinyl monomer, and a solvent with the addition of a small amount of an electrolyte supporting electrolyte.

2 0 9 8 1 5 / U 7 A BAD original

2H0850

The mixture is then placed in the electrolyte bath 3. The electrode 1 and the object 2 to be coated with a film are inserted into the bath 3. Buren the mixture is passed dannGleiciistroni _t where the electrode 1 and the object 2 are used as the electrodes. In this way, a film of cross-linked Tiny! Polymer deposited on the surface of the article 2, it is desirable ι electrolytic polymerization to take place at normal temperatures. The entire bath 3 is exposed to a nitrogen atmosphere. It is also possible for the polymerization to take place while nitrogen is bubbled through the mixture 4; alternatively, the process can also be carried out in the temperature range between the freezing point and the boiling point of the solvent Current density is two to 20 ma / cm. The time during which the current is passed through the mixture depends on the types of monomers used and on the solvent; after the end of the polymerization, a boiling process can take place above the boiling point of the solvent. It can, however, also be carried out at normal temperature.

Using the process described, a film of crosslinked, high molecular weight vinyl polymer is produced * which is insoluble in the solvent used. For the Production of the film of importance is the use of yinyl monomers and bivinyl monomers, the adhesion properties » the hiii'te and the flexibility of the manufactured in this way Films are better than those of the films obtained with the existing methods »Because the film is directly through the production of a crosslinked monomer is produced, an article having a complicated configuration can also be produced.

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By suitable adjustment of the electrolytic conditions the film thickness can also be influenced very easily. The film that can be achieved with the aid of the method according to the invention is required no subsequent hardening.

The following data gives the details of a comparative experiment and several embodiments according to the invention at.

Comparative experiment:

Acrylonitrile 20 g

Acetonitrile 80 g

Mckee's salt 2 g

In the indicated mixture, a carbon rod was used as the anode and an aluminum plate was used as the cathode. 3 minutes

DC current was conducted at a current density of 10 inii / cm while bubbling nitrogen at a temperature of 25 ° C for a long time. A yellow polyacrylonitrile film was formed on the aluminum plate. The film had a low molecular weight. Di ^ Adhäsionseigensehaften, hardness and ψ flexibility were insufficient for practical purposes. The relevant test results are given below in the form of a table.

Exemplary embodiments of the invention are given below:

Embodiment Ho. 1:

Acrylnitirl '10 g

NiN'-methylene-bis-acrylamide 5 g

Dimethylformamide 85 g

Mckee's salt 2 g

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The electrolysis of the indicated mixture was carried out under the same Conditions carried out as in the comparison test given above. A yellow film resulted on the Aluminum plate. After a drying process of 10 minutes at 150 ° C resulted in a crosslinked polymer film, which in the Solvent was insoluble.

Embodiment Uo. 2;

Acrylnitirl 10 g ϊϊ, 1T '-Methylene-bis- Acrylamide 10 g Dimethylaeetamide 80 g Mckee's salt 2 g

The indicated mixture was carried out under the same conditions as indicated above for the comparative experiment. A yellow film resulted on the aluminum plate. It was a continuous crosslinked polymer film that was insoluble in the solvent. The drying lasted 20 minutes at 5O ⁰ C.

Embodiment Uo. 3:

Methyl methacrylate 30 g

Ethylene glycol

dimethacrylate 3 g

Dimethylformamide 67 g

Mckee's salt 2g

A carbon rod was used as the anode and an aluminum plate was used as the cathode. For 5 minutes, current at a current density of 2 mA / cm was passed through the mixture of the specified composition at a temperature of 25 ° C. while purging with nitrogen. A film resulted on the aluminum plate. After drying at 100 ^° C. for 20 minutes

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33 G 5 G 62 G 2

Ulm emerged as colorless, more transparent, more networked Polymer film that was insoluble in the solvent.

Embodiment Ho «4:

Methacrylonitrile

Ethylene glycol
dimethacrylate

Acetonitrile
Mckee's dalζ

When mixing the specified composition, a carbon rod was used as the anode and an iron plate was used as the cathode. The current density was 10 mA / cm. The duration of exposure to electricity was 3 minutes. Bs was purged with btickstoff at 25 ⁰ C. There was a PiIm on the Bisenplatte. Mach a 20-minute drying at 5O ⁰ C, this cross-linked polymer film that was insoluble in the solvent yielded as a yellowish brown.

Embodiment Üfo. 5:

Glycidyl methacrylate 20 g

iithylacrylate 10 g

Divinyl sulfone 5 g

Dimethylacetamide 65 g

Tetraethylammonium chloride 0.5 g

When mixing the specified composition, a carbon rod was used as the anode and an iron plate was used as the cathode. The mixture was bubbled through the mixture at an airflow density of 10 iaa / cm for 3 minutes while nitrogen was bubbled through at 25 ° C. A film resulted on the iron plate which was used as a cathode. After drying for 20 minutes at 100 ^° C., a yellowish-brown, crosslinked polymer film resulted which was insoluble in the solvent.

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.Example Ho. 6:

methacrylonitrile Me tliylviny Ike t on

IT, H'-methylene-bi-sacrylamide

Dimethylformamide Hckee's courtship

30th G 18th S. 2 G 50 G O, 5 g

In the specified mixture, a carbon rod was used as the anode and a copper plate is used as a cathode. It was

ο cm for 3 minutes current passed at a current density of 25 mA / through the mixture under bubbling of nitrogen at 25 ⁰ C. A film resulted on the copper plate. After a 20-minute drying at 100 ⁰ G, resulted in a yellow, he linked Polymerfiin, which was insoluble in the solvent.

Embodiment ~ Ho. 7:

Methacrylonitrile 25 g

Vinyl acetate 10 g

G-lycidyl acrylate 10 g

Divinyl sulfone 3 g

Dimethylformamide 52 g

Mckee's salt 0.5 g

The anode was a carbon rod, the cathode an aluminum

Xjlatte used. It became electricity with a current density of

25 mix / cm was passed through the mixture for 3 minutes while bubbling nitrogen through it at 25 ° G. There was a jam on the aluminum plate. After drying for 20 minutes at 10O ⁰ O, a yellow, crosslinked! - polymer film resulted, which was insoluble in the solvent.

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The films obtained in your comparative experiment and the working examples 1 to 7 of the invention became different
exposed to physical tests. The results are given in the following table:

Procedure hardship

(Pencil)

Cross-hatch - re-test (Tape stand test) * ability

with boiling water

solubility

Comparison
attempt 2 HB 0/100 45 Min. soluble in
^ c eton Execution
example 1 3 2H ^93/1 OO 18th iitd. insoluble
in .acetone Il 4th 2H 100/100 1ö Il Il Il 5 3H 100/100 12th Il Il ir 6th 2H 100/100 16 ti 11 Il 7th 3H 100/100 12th Il Il Il H 90/100 10 Il Il ti H 93/100 10 Il Il

* The specified test procedure corresponds to JI3-K-5400.

Patentana test

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Claims (7)

Patent claims: Π .. Process for producing a film on the surface an object made of metal by way of electrolytic polymerization, characterized in that a mixture from vinyl monoiner, bivinyl monomer, one the conductivity the mixture increasing electrolytes, and a polar organic solvent made with the film too The coating object is inserted into the mixture as one of the electrodes, direct current is passed through the mixture and so a film of crosslinked vinyl polymer is formed on the surface of the article. 2. The method according to claim 1, characterized in that the vinyl monoiner is selected from the following group: acrylonitrile, Methacrylonitrile, an ester or amide of methacrylic acid or acrylic acid, styrene, ct-methylstyrene, butadiene, methyl vinyl ketone. 3. The method according to claim 1, characterized in that the Divin5'lmonomer is selected from the following group: lijii'-methylene-bis-acrylamide, a divinyl ester or ether of Ethylene glycol, divinylbenzene, divinyl sulfone, 1,5-hexadiene-3-yne, Hexatrienes. 4. The method according to claim 1, characterized in that the j £ lelrfcrolyt is selected from the following group: Mckee's balz, Tetraalkyl ammonium salt, nitrates or perchlorates of an alkali metal. 5. The method according to claim 1, characterized in that the polar organic solvent is selected from the following group is: dimethyl sulfoxide, dimethylformamide, acetonitrile, Pyridine, formamide, dimethylacetamide, nitrobenzene. - 12 - 209815 / U74 6. The method according to A _n sprueh-1, äadureh -marked that the electrolytic copolymerization takes place in a nitrogen atmosphere. ■ 7. The method according to claim 1 ", characterized in that the electrolytic copolymerization with bubbling through takes place of nitrogen through the mixture (4). 209815/1474