DE2016989B2 - Process for single-layer enamelling of strips and sheets - Google Patents

Description

bb) a methacrylic acid ester whose ester group-containing sulfate electrolyte is used and the co-

from an aliphatic straight-chain or bait at a current density of 3 to 10 A / dm ^a in one

branched-chain hydrocarbon residue with a time of 6 to 15 seconds on the sheet or strip.

1 to 6 carbon atoms can be separated.

_s j _ndi 5 should advantageously simultaneously in addition to iron

at least one or at most two foreign metals

b) 1 to 98 percent by weight of another is deposited with the, so it is advisable to use a compatible film-forming binding _{tape or B] ecn from e} j _nem divalent iron as well as from the group of coumarone resins and / at the same time one or two of the metals manganese in or the ketone resins, optionally in a combination of _{an amount of} 1 to 20 g / l - introduced as manganese ion with a hydrogenated abietyl alcohol, _suIfat _ nj _c i «: 1 in an amount of 10 to 50 g / l ,

c) 1 to 40 percent by weight of a benzene dicarbonate containing cobalt in an amount of 10 to 50 g / l acid ester, this electrolyte at a current density of 5 to

20 A / dm ² to be deposited in a time of 10 to 30 seconds.

which is deformable after baking and 15 For the chemical aftertreatment for passivation at the temperatures used for enamelling, the strip provided with the metallic layer completely and residue-free with volatilization or sheet metal, it is advantageously depolymerized in a, with the enamel frits to one 1 to 8 percent by volume nitric acid with a spatial coating on the strip or sheet is tempered and melted for a time of 5 to 20 seconds. In a preferred embodiment, while in an anodic aftertreatment, the lacquer, based on the solid body, contains a current component as a substantial content in 10% by volume sulfuric acid: density of 10 A / dm ² at a temperature of 40 to

,, 80 ° C and a time of about 10 seconds are required.

a) 70 to 92 percent by weight of an acrylate resin _? _ _{W Erläute} out the method according to the invention polymers, the structure element comprises a meth ^ _is to point _{out the following:} In the Säurebehandacrylsaureester is, _{at the beginning of development are of} v f _{He ahrens} the _zunäcnst

b) 3 to 20 weight percent of the neutralized other with the ^{NEN of degreasing} on the B'echoberfläche would remain component a compatible film-forming bond alkaline residues and the surface easily demittels / oxidized from the group of coumarone and wherein no material of the Sheet metal surface or the ketone resins, if necessary in combination 3 ° is removed. The formed thin oxide layer nation with a hydrogenated abietyl alcohol, supports in the following process step the formation of a likewise relatively thin, porous

c) 5 to 20 weight percent of the _gene Benzoldicarbon- or spongy, non-contiguous säureesters. Metal layer. The special mode of action of this

35 metal layer consists in the fact that the

AIs has expedient been found to lessen the-making email during baking the same coating at a temperature of 150 to 35O ⁰ C, time as the deposited metal layer and having preferably 160 to 300 ⁰ C, in a time of 30 min the slightly to burn in oxidized base material through the pores up to 15 see and the depolymerization can react at through, so that temperatures from 500 ⁰ C, preferably from 700 ⁰ C, 40 z. B. Iron titanates, which perform the good adhesion of the. Enamels on the base material with mediation Establish the acid treatment required at the beginning of the process to produce the oxide layer that thins the oxide layer and the porous metal layer. Depending on the following process steps, the porous metal layer is partially converted into a metal oxide layer when the sheet metal or strip is converted into 3 to 8 volumes, which acts as a promoter for the adhesive reaction of percent nitric acid chemically at room temperature. between the enamel and the base or carrier material is treated for 30 to 60 seconds, or the tape is used while the enamel is being burned in,
or sheet metal in 3 to 8 percent by volume nitric acid. In addition, the specification of the total anodic at a current density of 10 A / dm ² at a concentration of up to 50 g / l of foreign metals at room temperature relates to about 10 seconds. In 50 (calculated as metal) on the method according to the expedient manner, the bath can be found in a quantity in which the deposition of iron and 10 percent by volume sulfuric acid (100%) can be added to one or two of the foreign metals together in the bath in the case of anodic acid - an electrolyte is carried out. If, however, treatment at a temperature of 40 to 8O ⁰ C, the deposition of iron in a first bath and of only lOvolumprozentiger sulfuric loading 55 of one or two of the foreign metals carried out in a two-stand, ten bath, the second bath has a comparable For the application of the wipeable metallic, relatively high concentration of the layer to be deposited, various advantageous embodiments include foreign metals.

shapes possible. In a preferred manner, the advantages of the method according to the invention are

the sheet or strip after the acid treatment from 60 can be seen in particular in that in a simple manner

a divalent iron containing electrolyte a continuous, relatively short treatment

this at a stiom density of 5 to 10 A / dm ⁸ in the development of steel strips, with normal carbon

a time from 10 to JO see and subsequently from a fuel content of about 0.04 to 0.10% as well as with

non-inhibited nickel electrolytes, e.g. B. Watt's very low carbon content of about 0.006%

see or lemon acid type can be carried out at a current 65 in ¹ dei same manner, wherein

density of 3 to 10 A / dm ² in a time of 6 to 15 seconds on perfect and very adhesive enamel layers

Nickel is deposited, however, these strips or sheets can be manufactured in a more expedient manner

A cobalt can also be used instead of the nickel electrolyte.

7 8

The following is the procedure for single-layer 8. Anodic aftertreatment at 60 ° C in 10 volume

enamelling of steel strips and sheets using percent sulfuric acid and a current density

on particularly advantageous work processes, which vary from 10 A / dm ² , in a time of 10 see.

have already been tried and tested. 9. Rinse.

Example 1 ^S Example 3

1. Anodic degreasing in sodium hydroxide solution at a temperature of 80 ^° C. according to process steps 1 to 8 and at a current density of example 1 and process steps 1 to 9 of 15 A / dm ^a in a time of 6 seconds. Example 2 treated and then dried sheet

2. Rinse. i ° is used in a known manner, e.g. B. by painting,

3. Treat at room temperature in Svolumpro- dipping, spraying, rolling, a varnish applied in cent nitric acid in a time of 30 seconds. the white or colored pigmented enamel frits in

4. Rinse. an amount of 50 to 80 percent by weight

5. Cathodic deposition of iron, manganese are processed. The varnish comes in the form of a liquid and nickel from an electrolyte with the admixture 15 applied in organic solvents composition: and contains, depending on the paint-forming components

"""Γ-". , _{c cri} ,, j ^ x drew, as essential components:

70 g / l ferrous sulphate (FeSO ₄ 7H ₂ O), ^& '

10 g / l manganese (II) sulfate (MnSO ₄ 5H ₂ O), a) 1 to 98 percent by weight of an acrylate resin poly

100 g / 1 nickel sulfate (NiSO ₄ · 7H ₂ O), mers, its structural elements

20 g / l nickel chloride (NiCl ₂ · 6H ₂ O), aa) an acrylic acid ester whose ester group consists of

50 g / l magnesium sulfate (MgSO ₄ -7H ₂ O). a straight or branched chain

25 g / l ammonium sulfate, aliphatic hydrocarbon residue with 1 to

20 g / l boric acid, 6 carbon atoms, and / or

its pH value adjusted to 2.0 with sulfuric acid a ₅ ^bb ) ^a methacrylic acid ester, its ester group

represents is at a current density of 10 A / dm ² , from an aliphatic straight-chain or

a temperature of 6O ⁰ C, in a period of branched-chain hydrocarbon radical with

IQ _sec . Consists of 1 to 6 carbon atoms,

Anode material: soft carbon steel. are,

6. Rinse. 3o J ₃ ) 1 to 98 percent by weight of another with the

7. Post-treatment at room temperature in 5yolum component a compatible film-forming binding percentage Nitric acid in a period of means from the group of coumarone resins and / 20 see. or the ketone resins, optionally in combination

8. Rinse. nation with a hydrogenated abietyl alcohol,

B is ρ ie 1 2 ³ '^r> c) 1 to 40 percent by weight of a benzene dicarbon

. " _R , ... acid ester.

1. Anodic degreasing with caustic soda for a

Temperature of 8O ⁰ C, a current density of The lacquer coating is subsequently at a temperature

15 A / dm ² , in a time of 6 seconds. temperature from 150 to 35O ⁰ C, preferably 160 to

2. Rinse. 4 ° 300 ⁰ C, in a time of 30 min to 15 seconds into the

3. Treating at room temperature in 3volumpro- baked sheet metal, with the mentioned low cent nitric acid in a time of 30 seconds. Temperatures longer baking times and at the

3a) rinsing. higher temperatures correspondingly shorter

4. Cathodic deposition of iron is to be used for room burning times.

temperature from an electrolyte with the following 45 It should be noted that the temperature is above

the composition: step for the subsequent depolymerization of the paint

, "" Τ- · / · ττλ it *, r "cri 7u c \\ constituents is continuous or flowing and there

ί ™ ^gß n x] ^{Sen (} ^ ^S , fit rSso S m ^the stoving temperatures, which are preferably around

100g £ magnesium sulfate (MgSO ₄ -7H ₂ O), ^ß ^ _{h "her} ^^ _{melting point of the} inserted

50 g / l ammonium sulfate, ^ _{¥ me} ^^ ^ ₁ ^ _{,. ^ Can be increased}

its pH value adjusted to 2.0 with sulfuric acid

stelit is, at a current density of 10 A / dm ² , has a smooth, matt appearance, with dei

in a time of 10 seconds; Color of the enamel worked into the lacquer

Anode material: soft carbon steel. frit is dependent. The burned-in paint film is there

5. Rinse. 55 beyond that, mechanically not vulnerable, scratch-resistant

6. Cathodic deposition of cobalt for space impact resistant and hard. In particular, however, the strip or sheet provided with the following lacquer coating from an electrolyte is deformable to the composition: preferably deep-drawable, so that the end-use 300 g / l cobalt sulfate (CoSO ₄ · 7H _a O), _Ä ^ iJ " desired shape already with sheet metal or

20 gft sodium chloride, ⁶ ° tape manufacturer can be manufactured

an ση Ttnranre With the consumer, the paint film is at Tempe

wg / i Doraurc, temperatures of about 50O ⁰ C, preferably from 700 ⁰ C, ii

its pH value adjusted to 2.0 with sulfuric acid- an oven completely and residue-free under Ver

is, at a current density of 10 A / dm ² , volatilization of the paint components is depolymerized, where

in a time of 10 seconds. 65 with the enamel frit to a uniform, flawless!

7. Rinse. Enamel coating fuses.

Claims (15)

Patent claims: 1. Process for single-layer enamelling of a strip or sheet of steel, the strip or sheet metal degreased, acid-treated and electroplated with foreign metal before enamelling Coverings are provided, characterized in that the strip or sheet to generate a thin oxide layer in nitric acid or sulfuric acid chemically or is treated anodically that on the prepared strip or sheet one in the wet state wipeable porous or spongy metallic layer made of iron and one or two of the metals Nickel, cobalt, manganese electroplated from one or more baths at a temperature of room temperature to 80 ° C is deposited, with the use of only one bath the bath the Foreign metals nickel, cobalt and manganese added up to a total concentration of 50 g / l be, and that the strip or sheet for passivation chemically or anodically in acid in one Post-treatment time of 10 to 20 seconds and then dried, after which there is a stoving coating from a lacquer in which white or colored pigmented enamel frits are distributed, the lacquer being used in the form of a liquid mixture in organic solvents which, based on the paint-forming components, is an essential component a) 1 to 98 percent by weight of an acrylate resin polymer, its structural elements aa) an acrylic acid ester whose ester group consists of a straight or branched ₃ j-chain aliphatic hydrocarbon radical with 1 to 6 carbon atoms, and / or bb) a methacrylic acid ester whose ester group consists of an aliphatic straight-chain or branched-chain hydrocarbon radical with 1 to 6 carbon atoms, are, 45 b) 1 to 98 percent by weight of another with the component a compatible film-forming binder from the group of coumarone resins and / or the ketone resins, optionally in combination with a hydrogenated abietyl alcohol, c) 1 to 40 percent by weight of a benzene dicarboxylic acid ester which is deformable after baking and at the temperatures used for enamelling completely and residue-free depolymerized with volatilization, whereby the enamel frits fuse to form a uniform coating on the strip or sheet. 2. The method according to claim 1, characterized in that the strip or sheet metal is provided with a stoving coating of a lacquer which, based on the lacquer-forming components, contains as essential components: _g a) 70 to 92 percent by weight of an acrylate resin polymer, whose structural element is a methacrylic acid ester. b) 3 to 20 percent by weight of the other, compatible with component a, film-forming Binder from the group of coumarone resins and / or ketone resins, optionally in combination with a hydrogenated abietyl alcohol, c) 5 to 20 percent by weight of the benzene dicarboxylic acid ester. 3. The method according to claims 1 and 2, characterized in that the coating is baked at a temperature of 150 to 350 ⁰ C, preferably 160 to 300 ⁰ C, in a time of 30 rain to 15 seconds and the depolymerization at temperatures from 500 ⁰ C, preferably from 700 "C, is carried out. 4. Process according to Claims 1 to 3, characterized in that the strip or sheet metal chemically contributes to the production of the thin oxide layer in 3 to 8 volume percent nitric acid Room temperature is treated for 30 to 60 seconds. 5. The method according to claims 1 to 3, characterized in that the strip or sheet for producing the thin oxide layer is treated anodically in 3- to 8volumprozentiger nitric acid at a current density of 10 A / dm ² at room temperature for 10 seconds. 6. The method according to claims 1 and 5, characterized in that the strip or sheet metal is treated anodically in a bath which additionally contains 10 percent by volume sulfuric acid (100%). 7. The method according to claims 1 to 3, characterized in that the strip or sheet metal to produce the thin oxide layer is treated anodically in a bath made of 10% by volume Sulfuric acid. 8. The method according to claims 1 to 7, characterized in that on the sheet or strip of a divalent iron containing electrolyte this at a current density of 5 to 10 A / dm ² in a time of 10 to 30 seconds and subsequently from a not inhibited nickel electrolytes, e.g. B. the Wattschen or the citric acid type, at a current density of 3 to 10 A / dm ² in a time of 6 to 15 seconds nickel is deposited. 9. The method according to claims 1 to 7, characterized in that on the sheet or strip of a divalent iron containing electrolyte this at a current density of 5 to 10 A / dm ² in a time of 10 to 30 seconds and then from a cobalt containing sulfate electrolytes, the cobalt is deposited at a current density of 3 to 10 A / dm ² in a time of 6 to 15 seconds, 10. The method according to any one of claims 1 to 9, characterized in that on the strip or sheet of a divalent iron and at the same time one or two of the metals manganese in an amount of 1 to 20 g / l - introduced as manganese sulfate -, nickel in an amount of 10 to 50 g / l, cobalt in an amount of 10 to 50 g / l containing electrolytes these ^{are deposited at a current density of 5 to 20 A / dm 2} in a time of 10 to 30 seconds. 11. The method according to any one of claims 1 to 10, characterized in that the one with the metallic 3 4 see layered strip or sheet also chemically known (see. USA.-Patentschrift ?. 101 950), in 3 to 8 volume percent nitric acid in the pickled sheet with a heat dissipating room temperature in a time of 5 to 20 seconds for the salt solution to settle Post-treatment of nickel or cobalt to over-passivation. pulling the steel to decompose the salt solution 12. The method according to any one of claims 1 to 10, 5 heat, so that a nickel or cobalt coating is formed, characterized in that the metal is connected to the steel, and the sheet see layered strip or sheet anodic finally to treat with acid,
in 10 percent by volume sulfuric acid in one of these processes for separating a Current density of 10 A / dm ² at a temperature of the nickel and / or cobalt layer on the zn enamelling of 40 to 80 ° C in a time of 10 seconds to pass the sheets, it is also known (cf. French vierung is aftertreated. Patent 731 233), the steel used to make sheet metal for a single layer enamel is to be used with such metals, e.g. B. nickel, cobalt or Metalloids, alloy that passivate the 15 effect steel. Finally, there are also glaze-forming coatings for ceramic objects by firing made of glaze powder and a binding agent, The invention relates to a method for knowledge (cf. deutsche AusIegeschriftl011349,1089321), schichtemailliercn a strip or sheet of steel, including those made of ground glaze components where the tape or 31ech before enamelling is degreased and a binding agent such as synthetic resin, is thermo-greased, acid-treated and electroplated with foreign plastic masses, cellulose glue or the like, existing metal-containing coatings is provided. Coating layer by adding a plasticizer Process for single-layer enamelling of steel is designed as a flexible foil, and the foil with sheet metal, ie processes in which no base enamel is burned as the object to be coated,
are known. In one of these, the invention is based on the object Known processes (see British patent specification 763 379) Disadvantages of the known processes for single-layer, the sheet to be enamelled is first electro-enamelling of steel sheets or strips to vetlytisch degreased and after rinsing in water, avoid and in particular a process of this type on sulfuric acid or a mixture of formic acid 30, with which the treatment and nitric acid chemically or electrolytically pickled time is shortened in a simple way, a continuous treatment also and again rinsed. After pickling, that can be done by steel strips and with sheet metal in a nickel bath electrolytically with nickel that both steel sheets and strips with a norplated and subsequently enamelled. If the enamel paint carbon content as well as those that were previously not subjected to a decarburization treatment in a short time after nickel-plating, the sheet to be nickel-plated is electrolytically coated with a flawless and very adhesive enamel with a zinc layer, which is then coated can,
is then removed again before enamelling. One of these objects is achieved according to the invention However, sufficient adhesion between the steel sheet and a method of the type mentioned at the beginning in that of the enamel coating is solved by this method in such a way that the strip or sheet does not reach production. Deviating from this process, a thin oxide layer in nitric acid or it is also known (see. USA. Patent 2 748 066), sulfuric acid is chemically or anodically treated, after the pickling and before the application of the nickel that on the prepared strip or Sheet metal a layer of a treatment in 10% sulfuric acid when wet to ^{carry out wipeable porous or spongy about 80 0} C to remove the oxides from the surface metal layer of iron and one or two of the surface. Instead of the zinc protection metals nickel, cobalt, manganese galvanically from one layer, the nickel-plated bath or several baths can be oiled at the same temperature as sheet metal. Room temperature to 8O ⁰ C is deposited, wherein According to a further known method for the bath when using only one bath Enamelling of sheet metal (see German patent specification 5 ° foreign metals nickel, cobalt and manganese up to 828 626) electroplating of the sheet metal with a total concentration of 50 g / l is also added Suggested with nickel that the oxidizing thing, and that the strip or sheet for passivation glows and is subsequently celebrated. Instead of chemically or anodically in acid in a time of 10 Nickels can also be post-treated (see German Auslegeschrift up to 20 seconds) and then dried 1,017,876) cobalt or a mixture of nickel and 55, after which there is a stoving coating of a Cobalt (see French patent specification 1,286,330) uses varnish in which white or color-pigmented enamel is used will. The oxidizing glow when moderately-distributed frits are distributed, keeping the lacquer in shape nism moderately high temperatures and the subsequent cooling of a liquid mixture in organic solution Determine in a very specific atmosphere is used, the one on which varnish is allowed but related to a relatively large expenditure of components, as an essential requirement, so that this known method is not part of it either pacified. In addition to this known weight percent of an acrylate resin-poly go to another reference (see USA.- ^Λ) " , _ ^H , ■" ,, .. ^JJ Patent 2,755,210) proposed ^mers after oxy ^'whose structural elements denden annealing an acid treatment of the sheet 65 aa) an acrylic acid ester, whose ester group from perform. a straight or branched chain In addition to the electrolytic deposition of nickel aliphatic hydrocarbon residues with 1 to and cobalt on the sheet to be enamelled it consists of 6 carbon atoms, and / or