KR20190013516A - Sheet steel with a conversion coating, method of producing conversion-coated sheet steel and treatment agent for application of a conversion coating on sheet steel - Google Patents

Abstract

The present invention relates to a thin steel sheet having a conversion coating film, in particular a blackboard, wherein said conversion coating film is produced from components dissolved in water, said components being selected from the following group.
i) hexafluorotitanate,
ii) zinc phosphate and / or iron phosphate,
iii) phosphoric acid, and
iv) a mixture of any of i) to iii)
However, the components i), ii) and iii) do not contain any organic components.

Description

TECHNICAL FIELD [0001] The present invention relates to a thin steel sheet having a conversion coating film, a method for producing a conversion-coated thin steel sheet, and a treatment agent for applying a conversion coating film on a thin steel plate CONVERSION COATING ON SHEET STEEL}

The present invention relates to a thin steel sheet having a conversion coating film, a process for producing a conversion-coated thin steel sheet, and a treatment agent for applying a conversion coating film on a thin steel sheet.

In the prior art, it is known to protect said metal surfaces from corrosion by using a method of coating metal surfaces with coating films of different, generally less inert metals (e.g. zinc and chromium). Thus, for example, it is known to coat thin steel sheets with zinc or chromium or even tin (which is more inert than steel). In the production of packaging materials, in particular in the food sector, for example, tin-coated blackboards (tin plates) are used extensively. The remarkable features of tin plates are their excellent corrosion resistance, good formability and weldability, making them particularly convenient for use in the production of packaging materials, for example beverage cans.

Tin plates have excellent properties as a food packaging material and have been produced and processed for this purpose for decades. However, tin (which constitutes a corrosion-inhibiting coating film on tin plates) is becoming a relatively expensive material due to the increasing global lack of such resources. As an alternative to tin plates, it has been found to be advantageous to use thin steel sheets electrolytically coated with chromium and referred to as "tin-free steel sheets (TFS)" or " / RTI > On the other hand, the non-tinned steel sheet is characterized by excellent adhesion to a lacquer or an organic protective coating film (e.g. PP or PET), whereas the coating process is characterized in that the chromium (VI) -containing Toxic and health-hazardous properties of the material.

In order to protect the steel sheet against corrosion and to create a good adhesion surface for the lacquer and synthetic coating film, a conversion coating is often applied to the surface of the steel sheet. The targeted production of the conversion coating on the thin steel sheet (blackboard) prevents or at least delays corrosion of the thin steel sheet.

The conversion coating film is a very thin non-metallic coating film on the metal surface, and is generally produced by a chemical reaction between the aqueous processing solution and the metal substrate. Especially when applied to thin steel sheets (black boards having a thickness in the range of 0.1 to 0.5 mm), the conversion coatings provide highly effective protection against corrosion and a good adhesion surface for lacquers and composites, and reduce surface friction and wear .

Electrolytic application of conversion coatings to thin steel sheets is known from the prior art. Such conversion coatings are often produced from chromium electrolytes based on carcinogenic chromium (VI) oxide. However, due to court forbids, the use of such chromium (VI) -containing converted coatings is becoming increasingly rare. An alternative to conventional chromium (VI) electrolytes is treatment based on chromium (III) oxide or complex fluorides (titanium compounds, zirconium compounds). Another possibility of forming a conversion coating is phosphate formation with an aqueous phosphate solution.

DE 101 61 383 A1 describes a method of coating a metal surface comprising a steel surface with an aqueous composition free of chromium (VI) compounds, wherein the aqueous composition comprises, in addition to the aqueous solvent, at least one water-soluble or water- The content of cations and / or hexa-and tetrafluoro complexes selected from the group of organic film-forming materials Ti, Zr, Hf, Si, Al and B, the content of at least one of the particle form with a particle diameter of from 0.005 μm to 0.2 μm Of an inorganic compound, and optionally a silane and / or siloxane, and optionally also a corrosion inhibitor.

Conventional, commercially available, non-chromium agents for forming a conversion coating on metal include film-forming materials or organic solvents. In general, film-forming materials are polymers that impart a number of valuable properties to the conversion coating film, such as adhesion ability. However, the application of the polymeric material requires additional labor and equipment, which also makes the material more expensive. In general, the solvent contained in conventional non-chromium materials used in the formation of conversion coatings is more costly than water and poses some risk to human health during application of the conversion coating, and in most cases, (VOCs), which should be avoided due to the presence of organic compounds.

Therefore, a problem to be solved by the present invention is to make available a no-chromium agent for forming a conversion coating film on a thin plate. Furthermore, the present invention also relates to a thin steel sheet having a no-chromium conversion coating film and a method for producing the thin steel sheet as low as possible and in place of a tin-free steel sheet (TFS or ECCS) and a tin plate, An attempt is made to obtain a method of manufacturing the thin steel sheet comparable to a tin plate or a non-tinned steel sheet with respect to adhesion to an organic coating film.

The above problem is solved by a thin steel sheet according to claim 1, a method for producing a transformed-coated thin steel sheet according to claim 7, and a treating agent for applying a conversion coating film on a thin steel sheet according to claim 10.

Specifically, the thin steel sheet described in the present invention, which may be a strip-shaped blackboard or thin steel sheet coated with a corrosion-resistant metal film coating, has a conversion coating film on at least one surface, and the conversion coating film comprises at least Contains one

i) Hexafluorotitanate

ii) zinc phosphate and / or iron phosphate,

iii)

iv) or a mixture of components i) to iii), provided that the conversion coating film does not contain any organic material.

The conversion coating preferably comprises a mixture of one of components i) to iii) or a mixture of these components, most preferably a mixture of components i) and ii) or a mixture of all three components i), ii) and iii) .

In order to produce the thin steel sheet described in the present invention, a metal-coated or uncoated thin steel sheet (blackboard) is used, the surface of which is degreased in the first process step and subsequently washed with water or another cleaning liquid , And finally a wet film of the conversion coating film is applied by applying a wet film of a no-chromium treatment liquid consisting only of an inorganic component to at least one degreased surface of the thin steel sheet in the next step, Of the wet film is made from a component that is dissolved in water and the component is selected from the group consisting of hexafluorotitanate, zinc phosphate and / or iron phosphate, phosphoric acid and / or a mixture of these components, Of organic material and no inorganic particles having an average particle diameter of more than 0.005 mu m. The wet coating film volume is preferably in the range of 1 ml / m 2 to 10 ml / m 2. In the final step of the process disclosed by the present invention, the wet film of the conversion coating film is finally dried.

The ammochromium treatment liquid preferably contains only water and one of the components hexafluorotitanate, zinc phosphate and / or iron phosphate or phosphoric acid, or a mixture of these components, most preferably the component hexafluorotitanate and zinc Phosphate or a mixture of components hexafluorotitanate, zinc phosphate and phosphoric acid. During the drying of the wet film of the conversion coating film prepared from the aqueous treatment solution, the solvent (water) evaporates, so that the conversion coating film dried in the preferred embodiment embodiment is the only active component of the free- Hexafluorotitanate, zinc phosphate and / or iron phosphate and phosphoric acid, or a mixture of these active ingredients.

Preferred embodiments of the invention are set forth in the dependent claims. The invention will be described in more detail below:

The starting materials of the steel sheet disclosed in the present invention are preferably cold-rolled, annealed, hot-rolled or hot-finished steel sheets made of steel having a carbon content of 20 to 1000 wt ppm. The thin steel sheet (blackboard) preferably has the following properties:

Tensile strength: 300 to 1000 MPa

Elongation at break: 1 to 40%

Thickness: 0.05 to 0.49 mm

Surface roughness: 0.1 to 1 占 퐉

The steel of the thin steel sheet may be, for example, a ferritic steel or multi-phase steel comprising a number of structural components, particularly ferrite, martensite, bainite and / or retained austenite. Such multi-phase steels are characterized by a high tensile strength of more than 500 MPa, and a high elongation at break of more than 10% at the same time. With respect to the intended use of the blackboard as the packaging steel, which is treated as disclosed by the present invention, it is preferable to use a cold reduced tin mill products - electrolytic tinplate and electrolytic chromium / chromium oxide coated steel (DIN EN 10202: 2001) "] Are used. The standard also defines, among other things, the analysis and mechanical properties of steel. The ranges of these grades are in particular TS230 (mild grade, batch-annealed, yield strength 230 MPa) to TH620 (with continuous annealing, 620 MPa). The thin steel sheet may also be a metal-coated thin steel sheet, for example an electrolytically tin-plated steel sheet.

The method disclosed in the present invention is preferably carried out by moving a thin steel sheet in strip form at a strip speed of greater than 200 m / min and less than 750 m / min and subjecting it to electrochemical pretreatment. In the pretreatment process, the moving thin steel sheet is firstly cleaned and degreased. Washing and degreasing are preferably caused by passing the thin steel sheet through the electrolyte as a cathode. The degreasing is carried out after the recrystallization annealing and the cold-rolled and recrystallized-annealed thin steel sheet is roughly hot-rolled or hot-worked such that the surface of the thin steel sheet during the wet hot rolling is heated to a water- It is extremely important because it causes contamination with oil, worn iron particles, soap and other contaminants during rolling. These contaminants are removed in the washing step.

In order to clean and degrease the thin steel sheet, the thin steel sheet may be passed through a washing tank containing, for example, an alkaline sodium hydroxide or potassium solution. The concentration of the alkaline degreasing agent is preferably in the range of 20 to 100 g / L at a bath temperature of 20 to 70 캜. The degreasing of the blackboard preferably takes place in two stages, where the first stage involves an immersion process and the second stage involves an electrolytic process with a current density of 2 to 30 A / dm ² . After degreasing, each surface of the blackboard strip is cleaned with triple cascade rinsing, for example, at a rate of 10 to 30 m < 3 > / h. If necessary, the oxide residue is passed through two additional successive soaking steps into an additional washing tank containing the said blackboard strips, for example, a hydrochloric acid pickle or a sulfuric acid pickle at a concentration of 10 to 120 g / L, It can be removed by passing it through the cleaning liquid. The temperature of the pickling solution and the washing water is typically in the range of 20 캜 to 60 캜.

After washing and degreasing, additional electrochemical treatment of the sheet steel can be performed to produce a uniform steel surface that provides a good attachment surface for the conversion coating. In the additional electrochemical treatment, the thin steel sheet is used as an anode and is passed through an alkaline electrolyte. The alkaline electrolyte may be, for example, a sodium hydroxide solution or a sodium carbonate solution (Na ₂ CO ₃ ).

After the anode treatment in the alkaline electrolyte, the thin steel sheet is washed with water or another cleaning liquid and subsequently dried. Drying can take place, for example, in a continuous drying furnace or by a blowing unit that blows on the surface of a thin steel sheet moving in a laminar flow of the hot air stream.

After cleaning and drying, the conversion coating is applied to at least one surface of the steel sheet. To this end, a wet film of an aqueous, free-chromium treatment liquid based solely on inorganic components is applied to the electrolytically pretreated and dried surface of the thin steel sheet. This is preferably carried out in a non-cleaning process in which the cleaning step after application of the wet film is omitted. The aqueous treatment liquid for forming the conversion coating film may be applied to the surface of the thin steel sheet by, for example, a roll coater or sprayed on the surface with a spray nozzle, for example, with a rotary atomizer.

After application of the wet film of the treatment liquid, the conversion coating film formed as described above is dried. To this end, the thin steel sheet is passed through a belt dryer, for example, to dry the wet film of the conversion coating. The drying preferably takes place at a temperature of from 50 캜 to 250 캜. After the conversion coating film is dried, a dry film of the conversion coating film formed as described above having a surface weight (on both sides) of 1 to 1000 mg / m 2, preferably 10 mg / m 2 to 400 mg / Lt; / RTI > The desired dry film thickness of the conversion coating can be controlled by the amount of aqueous processing solution delivered per unit time in the application step. If necessary, the surface weight of the applied conversion coating may also be controlled by squeezing and dewatering any excess treatment liquid prior to the drying step.

As a final step, the surface of the dry conversion coating film is treated with a solvent such as dioctyl sebacate (DOS), acetyl tributyl citrate (ATBC), butyl stearate (BSO) or polyalkylene glycol, especially polyethylene glycol (PEG, g / mole), or a combination thereof.

The aqueous treating solution used for applying the conversion coating film to the thin steel sheet contains at least one of the following components in addition to the water solvent:

i) hexafluorotitanate,

ii) zinc phosphate and / or iron phosphate,

iii)

Or mixtures of components i) to iii), provided that components i) to iii) do not contain any organic material.

In a preferred embodiment, the aqueous treating solution comprises, in addition to the water solvent, the following components or mixtures thereof (unless otherwise stated, all parts and percentages refer to parts by weight and percentages):

- hexafluorotitanic acid [CAS: 17439-11-1],

- zinc phosphate [CAS: 14485-28-0] and / or iron phosphate [CAS: 10045-86-0]

- a mixture of hexafluorotitanic acid and zinc phosphate and / or iron phosphate,

A mixture of hexafluorotitanic acid and phosphoric acid,

- a mixture of hexafluorotitanic acid, zinc phosphate and / or iron phosphate and phosphoric acid, or

- a mixture of zinc phosphate and / or iron phosphate and phosphoric acid.

The effect of the treatment liquid and the properties of the conversion coating film vary depending on the concentration of components used in the aqueous treatment solution and the wet film volume of the aqueous treatment solution on the surface of the steel sheet.

In the aqueous treatment liquid, the above-mentioned components of the conversion coating film can be used, for example, at the following concentrations, wherein these concentrations are equally applied to any mixture of the components:

Hexafluorotitanic acid: 1%, 3%, 5%, 7% and 10% (note that these values can also be regarded as boundaries for any range of possible concentrations);

Zinc phosphate (Zn ₃ (PO ₄ ) ₂ ): 1%, 3%, 5%, 7% and 10% and correspondingly derivable concentration ranges;

Iron phosphate (FePO ₄ ): 1%, 3%, 5%, 7% and 10% and correspondingly derivable concentration ranges;

(Zn ₃ (PO ₄ ) ₂ ) and / or iron phosphate (FePO ₄ ) in the mixture with phosphoric acid: the same concentrations as given above for zinc phosphate and iron phosphate + 1.4%, 2.3%, 3.2% % ≪ / RTI > and 5.5% phosphoric acid and correspondingly derivable concentration ranges therefrom;

2.5:: 1 to 4: 10: mixture of titanic acid, and zinc phosphate as a 4-hexafluoro-phosphate ratio of the addition of TiPO _4, i.e. first on the starting concentration of the same ingredients as set forth above for the zinc titanate and hexafluorophosphate.

For the conversion coating film disclosed in the present invention containing titanium, that is to say for a conversion coating film containing a hexafluorotitanate-containing conversion coating film or a mixture of hexafluorotitanate and phosphate, a preferred dry coating for titanium The weight was found to be in the range of 1 mg / m 2 to 50 mg / m 2, preferably in the range of 10 mg / m 2 to 40 mg / m 2. For the conversion coatings described in the present invention containing phosphates, that is to say for conversion coating films prepared from or containing zinc phosphate or iron phosphate, the preferred dry coating weight for the phosphate ions is from 10 mg / m2 to 1000 mg / m2 And preferably in the range of from 100 mg / m 2 to 400 mg / m 2.

Example

In the following, embodiments of the present invention will be described in detail. The specified concentration of treatment liquid components applied to produce the conversion coating on the surface of the steel sheet refers to the treatment solution by itself and does not refer to the starting solution possibly used at higher concentrations. All concentrations provided refer to parts by weight of the active ingredients in the aqueous treatment liquor, whether or not the raw materials used as such are already diluted as an aqueous solution, for example.

Embodiment For the test in the example, a test sheet in the form of a blackboard sheet (uncoated, cold-rolled thin steel sheet) having a thickness of 0.27 mm was used. The surface of the test sheet was first cathode degreased (time = 30s, temperature = 38 ° C, current = 5 A / dm ³ ) in a 5% sodium carbonate solution Na ₂ CO ₃ and subsequently washed with water and deionized water. Using a roll coater (LARA), a wet film of the aqueous treatment liquid as listed in Table 1 was applied to the degreased surface and subsequently dried in a drying chamber (time = 50s, temperature 98 [deg.] C). The surface weight of the resulting conversion coating film (dry weight of the treatment liquid) is listed in Table 1. The surface of the conversion-coated test sheet was subsequently inspected. The dry weight of the conversion coating film was measured by XRF, and the test sheet was subjected to cyclic voltammetry to measure the electron mobility barrier. The current density was measured at a potential of -770 mV. This is characteristic of the oxidation of iron to its bivalent form. The higher the above measurement value, the greater the oxidizing property. The results of the measurement of the dried coating weight and the cyclic voltammetry method are listed in Table 1.

In the conversion coating film containing hexafluorotitanate, the values measured by cyclic voltammetry and listed in Table 1 are relatively high, indicating that the coating is permeable. The value of the conversion coating containing phosphate (zinc phosphate, iron phosphate) is invariably lower, indicating an opaque, dense coating film. Thus, with respect to the oxidative properties, the phosphate-containing conversion coating film has better properties and, in particular, higher corrosion resistance. Measurement by cyclic voltammetry indicates that the combination of hexafluorotitanate or hexafluorotitanic acid with zinc phosphate yields a surprisingly favorable result (10 μA / cm 2 vs. 50 μA / cm 2). These values are within the range of commercially available agents having a complex structure for use in the production of a metal-on-transition coating. Hexafluorotitanate or hexafluorotitanic acid and zinc phosphate and / or iron phosphate and water as solvent, in particular 1 to 10% in the case of said hexafluorotitanic acid and (total) in the case of zinc phosphate and / or iron phosphate, The amount of the titanium-containing conversion coating film and the amount of the phosphate-containing conversion coating film can be combined by preparing the aqueous treatment liquid from a mixture of 1 to 10% by weight. In addition, phosphoric acid may be added to the above preferred mixture, for example, in a weight percentage of 1 to 10%. The addition of the phosphoric acid provides the advantage that the zinc phosphate can be dissolved.

Subsequently, four different lacquers (Gold lacquer AN 101.597 with a coating weight of 5 g / m 2; Gold lacquer BPA NI Metlac 816714 with a coating weight of 5 g / m 2) having a coating weight of 5 g / m 2 Gold lacquer GL 300 MF; White lacquer BPA NI Valspar R 1016 with a coating weight of 15 g / m 2) was applied to the dried conversion coating and the lacquered test sheet was subjected to load testing (modification and sterilization) And the lacquer adhesion was evaluated by testing using a cross-cut test and an Erichsen scale. For this, a score-scoring system was used, where scores from 0 (no attachment) to 7 (optimal attachment) were assigned according to the quality of the lacquer attachment. The scores provided for the conversion coatings for the different lacquers are added together, and the sum added is listed in Table 2. The higher the total value is, the better the adhesion of the conversion coating film to the organic lacquer is.

Table 2 shows that conversion coatings made of hexafluorotitanate produce the best results with respect to lacquer adhesion and that the adhesion increases with increasing coating weight. For conversion coatings with phosphate (zinc phosphate, iron phosphate), lower coating weights tend to improve lacquer adhesion and, given the same coating weight, adhesion of zinc phosphate is found to be better than for iron phosphate lost. Therefore, zinc has a positive effect on lacquer adhesion. Zinc may be present at a coating weight corresponding to any of the above-mentioned coating weight ranges when the conversion coating comprises a zinc phosphate component. Conversion coatings having a zinc weight percentage of 1% to 5% (based on the total weight of the conversion coating), preferably 2 to 4% zinc, have been found to be particularly advantageous.

The results of the lacquer adhesion test were compared to the results of a comparative sample made with conventional tin-free steel sheets (ECCS or TFS) and the commercially available material "Bonderite (R)" (Henkel) ) Coated steel sheets. The conventional un-tinned steel sheet (ECCS or TFS) provided an overall score of 115 and, depending on the coating weight, the thin steel sheet coated with the "Bonderel TM" provided an overall score of 88 to 118.

On the basis of a comparative test on the different coating weights (surface weights) of the conversion coatings, a conversion coating with hexafluorotitanate with a coating weight of less than about 50 mg / m 2 (relative to titanium) proved to give good results Could. Therefore, the preferred range of surface weight (relative to titanium) of the conversion coating film is 1 to 50 mg / m2, more preferably 3 to 40 mg / m2, particularly 10 to 40 mg / m2, or even 20 to 40 mg / Lt; 2 > or 15 to 30 mg / m < 2 >.

In the case of a phosphate coating, a coating weight of less than or equal to about 500 mg / m < 2 > (relative to the phosphate ion PO ₄ ) achieves good results. Thus, the preferred range of surface weight of the conversion layer relative to phosphate (PO ₄ ) is from 10 to 500 mg / m 2, more preferably from 20 to 400 mg / m 2, especially from 50 to 300 mg / m 2 or even from 100 to 250 mg / M < 2 > or 150 to 300 mg / m < 2 >.

In another test, the formability of the lacquered test sheet was examined. For this, the lacquered test sheet was formed into a beta-2 cup by deep drawing. On the other hand, it has been found that a conversion coating film having hexafluorotitanate (hexafluorotitanic acid) is performed best even when an extreme deformation is applied. On the other hand, from the results of the moldability test, it was found that the titanium-containing conversion coating film having a coating requirement of > 40 mg / m 2 was inferior, .

In addition, a test was performed to laminate the conversion-coated test sheet with a film (instead of a lacquer coating). After deep-drawing the film-laminated test sheet to form a standard cup, irradiation was conducted to test desorption of the film laminate.

For each of the test solutions disclosed by the present invention, the obtained test results show that after a short thermal post-treatment, the adhesion values are very good and are equivalent to those of commercially available complex transformants with organic materials .

In general, the results show that, in order to produce a conversion coating film on a thin steel sheet containing organic compounds in the form of particles having a particle size of greater than 50 nm and organic materials (for example polymers and organic film-formers) Indicates that there is no need to use a complex treatment liquid to achieve good adhesion properties to the lacquer and plastic laminate. As described in the present invention, comparable results are obtained with a pure inorganic treatment liquid of a simpler composition which is limited to the active ingredients and thus is less expensive, which is comparable to conventional chromium-containing conversion coatings on thin steel sheets .

Thus, based on the present invention, it is concluded that a coating film having a titanium active ingredient in the titanium coating weight range of 1 mg / m 2 to 50 mg / m 2, preferably in the range of 10 mg / m 2 to 40 mg / . In the phosphate-containing conversion coating film disclosed by the present invention, elemental zinc has a positive effect on the above properties and yields good results with a zinc concentration of 5% or less.

The method disclosed by the present invention can be integrated into existing coating lines, for example, without significant equipment installation costs and labor in the strip coating lines used in ECCS (or TFS) production. In such a strip coating line, the strip speed is typically 80 to 600 m / min.

The process disclosed in the present invention has the advantage that the thin steel sheet can be coated with a non-chromium conversion coating film, which is based only on inorganic components and thus is environmentally friendly, health-compatible and very cost-effective. The steel sheet treated as described in the present invention has excellent compatibility with the production of packaging materials, especially cans, and thus can replace tin plates and tin-free steel sheets (TFS or ECCS) commonly used in packaging steel sheets. A blackboard (a cold-rolled thin steel sheet without a metal coating) coated with a conversion coating film is comparable to a tin plate with respect to its corrosion resistance, and similarly, an organic lacquer and a plastic coating film (for example, PP Or < / RTI > of PET).

No. Active ingredient density
(wt%) menstruum Coating weight
(Mg / m ² ) Cyclic voltammetric method
(μA / cm 2)
1. Circulation / 2. Circulation One Hexafluorotitanic acid 1.0 water 5.0 118.8 2 Hexafluorotitanic acid 3.0 water 12.0 93.0 3 Hexafluorotitanic acid 5.0 water 13.0 131.4 4 Hexafluorotitanic acid 7.0 water 28.0 114.0 5 Hexafluorotitanic acid 10.0 water 39.0 154.0 6 Zinc phosphate
Phosphoric acid (85%) 1.0
1.4 water 120 12.6 7 Zinc phosphate
Phosphoric acid (85%) 3.0
2.3 water 205 15.2 8 Zinc phosphate
Phosphoric acid (85%) 5.0
3.2 water 383 21.0 9 Zinc phosphate
Phosphoric acid (85%) 7.0
4.1 water 417 10.7 10 Zinc phosphate
Phosphoric acid (85%) 10.0
5.5 water 592 7.7 11 Iron phosphate
Phosphoric acid (85%) 1.0
4.5 water 348 24.5 12 Iron phosphate
Phosphoric acid (85%) 3.0
5.7 water 583 18.7 13 Iron phosphate
Phosphoric acid (85%) 5.0
6.9 water 671 24.2 14 Iron phosphate
Phosphoric acid (85%) 7.0
8.1 water 968 14.5 15 Iron phosphate
Phosphoric acid (85%) 10.0
9.9 water 1153 57.6 16 Hexafluorotitanic acid
Zinc phosphate
Phosphoric acid 1.0
2.0
3.0 water 52.0 17 Hexafluorotitanic acid
Zinc phosphate
Phosphoric acid 1.0
2.5
1.0 water 52.4 17.2 / 38.0

No. Active ingredient Concentration (wt%) menstruum Coating weight
(Mg / m ² ) Overall score for lacquer attachment
One Hexafluorotitanic acid 1.0 water 5.0 115 2 Hexafluorotitanic acid 3.0 water 12.0 116 3 Hexafluorotitanic acid 5.0 water 13.0 118 4 Hexafluorotitanic acid 7.0 water 28.0 120 5 Hexafluorotitanic acid 10.0 water 39.0 130 6 Zinc phosphate
Phosphoric acid (85%) 1.0
1.4 water 120 109 7 Zinc phosphate
Phosphoric acid (85%) 3.0
2.3 water 205 90 8 Zinc phosphate
Phosphoric acid (85%) 5.0
3.2 water 383 110 9 Zinc phosphate
Phosphoric acid (85%) 7.0
4.1 water 417 65 10 Zinc phosphate
Phosphoric acid (85%) 10.0
5.5 water 592 77 11 Iron phosphate
Phosphoric acid (85%) 1.0
4.5 water 348 88 12 Iron phosphate
Phosphoric acid (85%) 3.0
5.7 water 583 86 13 Iron phosphate
Phosphoric acid (85%) 5.0
6.9 water 671 78 14 Iron phosphate
Phosphoric acid (85%) 7.0
8.1 water 968 98 15 Iron phosphate
Phosphoric acid (85%) 10.0
9.9 water 1153 83 16 Hexafluorotitanic acid
Zinc phosphate
Phosphoric acid 1.0
2.0
3.0 water 52.0 17 Hexafluorotitanic acid
Zinc phosphate
Phosphoric acid 1.0
2.5
1.0 water 52.4 87

Claims (12)

A thin steel sheet having a conversion coating on at least one surface, wherein the conversion coating comprises at least one of the following components:
i) hexafluorotitanate,
ii) zinc phosphate and / or iron phosphate,
iii)
However, the components i), ii) and iii) do not contain any organic components. The method according to claim 1,
A thin steel plate in which the conversion coating film is composed of one of the following components or a mixture of these components:
i) hexafluorotitanate,
ii) zinc phosphate and / or iron phosphate,
iii)
However, the components i), ii) and iii) do not contain any organic components. 3. The method according to claim 1 or 2,
A thin steel plate in which an organic lacquer and / or a plastic coating is applied to the conversion coating. 4. The method according to any one of claims 1 to 3,
Wherein the conversion coating film contains phosphate ions. 5. The method according to any one of claims 1 to 4,
The coating weight of hexafluorotitanate in the conversion coating film is in the range of 1 mg / m2 to 50 mg / m2, preferably 10 mg / m2 to 40 mg / m2 as compared to titanium. 6. The method according to any one of claims 1 to 5,
Wherein the coating weight of the phosphate in the conversion coating film is in the range of 10 mg / m 2 to 1000 mg / m 2, more preferably 100 mg / m 2 to 400 mg / m 2 as compared to the phosphate ion. As a method for producing a transformed-coated thin steel sheet,
a) obtain a thin steel sheet, in particular in the form of a steel strip;
b) cathodic degreasing at least one surface of the thin steel sheet;
c) applying a wet film of the conversion coating film to the degreased surface of the thin steel sheet, wherein the wet film of the conversion coating film is produced from the components dissolved in water, and wherein the components are selected from the group consisting of:
i) hexafluorotitanate,
ii) zinc phosphate and / or iron phosphate,
iii) phosphoric acid, and
iv) a mixture of any one of i) to iii)
However, the components do not contain any organic material;
d) drying the wet film of the conversion coating film
≪ / RTI > 8. The method of claim 7,
A method of applying an organic lacquer and / or a plastic coating to a dried conversion coating. 9. The method according to claim 7 or 8,
After degreasing the cathode, the degreased surface of the thin steel sheet is anodically polarized in an alkaline electrolyte. A treatment agent for applying a conversion coating film to a thin steel sheet, wherein the treatment agent contains water and at least one component selected from the group consisting of:
i) hexafluorotitanate,
ii) zinc phosphate and / or iron phosphate,
iii) phosphoric acid and
iv) a mixture of any one of i) to iii)
However, the components i), ii) and iii) are free of organic components. 11. The method of claim 10,
Water and a mixture of hexafluorotitanate, zinc phosphate and / or iron phosphate and phosphoric acid. 11. The method of claim 10,
Water and a treating agent consisting solely of one of the following components or a mixture of these components:
i) hexafluorotitanate,
ii) zinc phosphate and / or iron phosphate,
iii) Phosphoric acid
However, the components i), ii) and iii) do not contain any organic components.