DE1669159B2 - Production of air or thermosetting coatings on metal surfaces - Google Patents

Description

1 2

The invention relates to the production of impurities which have a corrosive effect

air or heat curable coatings on metal surfaces.

surfaces and in particular on the protection of the finished It is assumed that the alkali borate as VerOberfläche of steel strips, plates, sheets or wetting agents for the alginate acts, whereby the Like., which consist mainly of stainless steel. 5 Formation of a glue with good film-forming properties

For the sake of simplicity, the invention will be brought about, which works well on the metal

pungent only described with reference to it, it is surface adheres.

however, it can be seen that the invention is generally based on the protective properties of the alginate film

Protection of metal surfaces, ζ. B. made of copper, aluminum by adding a small amount of preferred

minium or their alloys, is applicable. io wise sodium silicate improved to the coating solution.

When making steel belts, plates, the addition of silicate to the film gives it one

sheet metal or the like, it is common practice to use blocks with a high degree of resistance to scratches or

Series of rolling operations to be subjected to the scuffs.

Dimensions of the steel material to the appropriate The use of such materials is also

Reduce sizes. 15 particularly advantageous by using a borax / alginate film

The first "passes" through the rollers are made under the influence of hot or cold solution

carried out, while the block can be loosened very quickly in a heated medium. Thus the

was present, however, while the final or finished transfer of any oil or fat from

usually increase in the cold state after removing an area of undissolved film to an area of

scaling and cleaning of the metal is carried out, the exposed steel surface is reduced to a minimum.

dcn. The finished product enters with a shiny, led,

flawless surface. It is actually believed that during the

During the subsequent handling of the solution of the film through a complete dissolution

Material, usually by hand, is the shiny the film held at some points on the surface-

The surface is very receptive to impressions, 25 and the solvent is then placed between the steel

z. B. fingerprints, oil or grease that penetrates the surface and the protective layer so that the

the gloves or on the hands of the protective layer around the steel surface rather in pieces

walking people. It is often necessary, omitted, than to be completely resolved in situ,

the finished steel after such handling with elastic masses are known which consist of a

organic solvents and / or cleaning paste made of sodium alginate with a content of borax

to clean or wash off agents in order to consist of such and glycerine and which cotton or as-

Remove imprints. Such a removal is best fibers are added, whereupon the mixture is

not only time-consuming and often ineffective, but molded and immersed in 10 η aluminum chloride solution

so uneconomical in some cases that large quantities become. Such masses are for another technical

Steel must be scrapped. 35 national territory and not for the purposes of

It is known that an invention is suitable for the finished steel surface.

Protective layer made of z. B. paper, thin plastic. The preferred solvent is water. the

to create scroll. However, such a mixture has been found to be preferably applied by

Solving the problem in general as unsatisfied. B. a steel belt through a bath from their aqueous

because of the high costs involved. 40 solution and air dry the coating

It is also used in galvanizing of strip. Warm air can circulate around the belt steel can be guided on one side by means of a zinc bath in order to make such drying known, the side to be galvanized with a flux, accelerate, and the bath can be at one temperature like a zinc ammonium chloride solution, to be coated between room temperature and the boiling point and the other side of the steel are held with a borate solution, 45, but at a temperature of such as B. a borax solution, after which both 70 to 75 ° C is preferred. A spray of the Coatings are dried on the belt. Protective hot solution can also be used in layers, those containing borate only give long lasting effects, but the treatment is generally straightforward limited protection. subjects.

It is also known to use anodically oxidized aluminum to ensure uniform deposition of the film-forming

In order to ensure the sodium silicate material with a sodium alginate solution, a small proportion

cium fluoride contains, to be treated in order to protect a wetting agent in the treatment solution.

to achieve coating. Such protective coatings must be available. The applied

no special durability. ratio of alginate to alkali borate is preferably

According to the invention, a mixture of a 55 at 8: 1. Ratios higher than 40: 1 result in one

water-soluble alginate, an alkali borate and a more fragile coating film, while lower

Alkali silicate, the ratio of alginate to ratios as 1: 1 result in coatings that are not so easy

Alkali borate between 1: 1 and 40: 1 and the surface can be removed by washing with solvents

ratio of alginate to alkali silicate between 5: 1 and can.

50: 1, and possibly a small proportion 60 The proportions or ratios of effective

cinc's surfactant and a corrosive component in the coating compositions are preferred

sion inhibitor for the production of air or heat within the following ranges (on a weight basis): curable coatings are used on metal surfaces.

The preferred alkali borate is borax, although soluble alginate is 40 to 80 ° /

also potassium, lithium and other alkali borates at 65 °

Can apply. The alginate used alkali borate 2 to 30 / "

should preferably be essentially free of impurities - alkali metal silicate 1 to 16%

especially of chlorine-containing agents. Surface-active agent 10 to 35%

The invention is explained in more detail below with the aid of examples.

example 1

An aqueous solution containing, on a weight basis, 0.25% borax (Na ₂ B ₄ O ₇ -IOH ₂ O), 2.00% sodium alginate and 1.00% of an anionic detergent was ^{heated to a temperature of 75 °} C. and used to fill a treatment vessel through which a freshly finished stainless steel belt was passed. The tape was dried with warm air as it emerged from the solution. Upon drying, a very pliable film was produced on the tape that did not break away from the metal surface under strict handling or when the tape was bent. However, the film was easily removed by washing the tape in hot water.

B e i s ρ i e I 2

0.25 percent by weight of sodium silicate (Na ₂ O / SiO ₂ ratio = 1: 2; 83% solids) was added to the solution described in Example 1, and a steel belt was treated with the solution in the same way as described in Example 1, treated. A tough, scratch-resistant film was formed on the steel surface which did not break away from the metal band under strict handling or when bent.

Thicker films can be made by increasing the concentrations of the film-forming materials in the treatment solution be generated. Such thicker films can be removed from the metal by hand peeling removed.

The protective effect of the above-described method of applying such a film can be done by adjusting the pH of the treatment solution to reduce the possibility of corrosion the steel surface can be reduced to a minimum. A pH of 8 to 10 is preferred. The protective film according to the invention can also be used as a carrier for other surface treatment agents, e.g. B. anti-corrosion agents such as nitrites and Chromates, as shown in Example 3 below. The proportion of the anti-corrosion agent can be up to 20 percent by weight of the active ingredients of the coating solution.

Example 3

A mixture was prepared from the powdered dry ingredients listed below and stored in dry mixed powder form.

Parts by weight

Borax (Na ₂ B ₄ O ₇ -1OH ₂ O) 0.75

Sodium alginate 3

Sodium dioctyl sulfosuccinate 1

Sodium nitrite 2

In the case of use, 10 parts by weight of the powder were only dissolved in 190 parts by weight of water, one for tape application as in the example 1, finished coating solution was obtained. A tape coated with this solution could easily handled without damage and could be handled without deterioration for a long period of time be stored.

As indicated in the above example, the coating compositions can be prepared in dry powder form to which only water has to be added to give a usable coating bath. To the To facilitate the solution formation stage, the active or effective ingredients can be in the form of a thick paste or slurry in a small amount of a suitable solvent, for example Isopropanol or glycerine.

Claims (3)

Patent claims: 1. Use of a mixture of a water-soluble alginate, an alkali borate and a Alkali silicate, the ratio of alginate to alkali borate between 1: 1 and 40: 1 and the ratio from alginate to alkali silicate is between 5: 1 and 50: 1, and possibly a low one Share of a surface-active agent and a corrosion inhibitor for the production of airborne or thermosetting coatings on metal surfaces. 2. Use of a mixture according to claim 1 from an aqueous solution, the pH of which is 8 to 10 is set. 3. Use of a mixture according to claim 1 from an aqueous solution at 70 to 75 ⁰ C.