DE2150762B2 - Means for removing rust and protecting against re-rusting - Google Patents

Description

the ability of the agent according to the invention at least as much as the other components of the preparation can

to a certain extent by the concentration of the corrosion inhibitor as such or preferred

the hydrochloric acid can be controlled, being added with in aqueous solution,

greater concentration in general the cleansing It is of great benefit, but not necessarily speed increases. 5 required, in the rust-removing agent as a further

The content of citric acid can in the middle ren constituent to include a thickener, vary between 7.5 to 25 percent by weight, where- The amount of this constituent can range from 0 to 6.5 percent by weight at contents of 17.5 to 20 percent by weight fluctuate, which are preferred. This constituent is important to ensure that amounts of 5.5 to 6.5% are used. As a tel, since it contributes to the overall effect of removing the thickener, methyl cellulose and rust can be used without difficulty in the use of similar thickeners, but there is handling and harmful gases are produced. Besides such additives, the danger that they are long assumed to degrade the extent of Rostrer's contact with acids. For the sake of the concentration of the whole reason, colloidal silicon dioxide acid, that is, from the amount of hydrochloric acid and citric acid, is preferably used as a thickening agent. When using nenic acid, which depends on the agent and of course colloidal silicon dioxide as a thickening agent, the amount used depends also on the amount to be cleaned. You need at least * the surface of the applied agent. at least 5.5 % of this means to achieve the desired good

The third essential component of the preparation is to create the nixotropic properties of the preparation.

tung is a surfactant. It should hold in the 20, and not more than 6.5%>, so that the preparation

Prepared in an amount of 0.5 to 5 weightings, not too thick for practical use

percent, but preferably in an amount of 2.0.

to 2.5 percent by weight. As an additional component, the preparation contains Surface-active agent can be any non-ionic, expediently an antifoam agent, where An amphoteric or amphoteric agent of this type uses this component in amounts from 0 to 0.2 weight percent, but currently the first mentioned percentages, preferably from 0.1 to 0.2 weight percent average preferably used. Specific examples of zent, is used. As an antifoam agent, a Nonionic surfactants include any of the common silicone antifoam agents: propylene glycol monostearate, organic based or base can be used. Be-glycerol monostearate, Glycerol oleostearate and sorbitan have particularly proven themselves in this preparation monolaurate, sorbitan monopaneity, sorbitanthio- higher alkyl alcohols as antifoam agents. Before the oleate, polyoxyethylene sorbitol laurate, polyoxyethylene use of too large amounts of antifoam sorbitol oleotelaurate, Nonylphenoxy-polyoxyethylene agents are foreseen, because they cause a nonethanol, Polyoxyethylene lauryl ether, myristic acid- desired thickening of the preparation occur diethanolamide, lauric acid diethanolamide, polyoxy- 35 can. Due to the presence of the antifoam Ethylene propylene glycol monostearate, iso-octylphene, the manageability and use of Zuoxy-polyoxyethylene-ethanol, Polyethylene glycol soy preparation made easier.

bean oil fatty acid ester, tetrasodium ethylenediamine, the preparation tetraacetic acid, isopropyl myristate and dimethyloctin- still contain dyes and fragrances in order to achieve the diol. Specific examples of amphoteric surface-40 appearance and smell of the preparation to be surface-active Means include the following: mend. In choosing such fabrics, it is self-evident Sodium salt of N-coconut beta-aminopropionate, understandable to ensure that the added the disodium salt of N-tallow-beta-aminodipro products the essential property of the preparation pionate, the disodium salt of N-lauryl-beta-amino- tung, d. H. do not affect the rust removal, dipropionate, the sodium salt of N-lauryl-beta-45 The last essential component of the aminopropionate, the triethanolamine salt of N-Lung is water. It doesn't just serve as a carrier for ryl-beta-aminopropionate, N-methyltaurine, sodium- the other components of the remedy, rather it N-methyl taurate and cetyl betaine. The surface contributes to the removal of rust from the top-active agent, the preparation as such or surface, by preventing redeposition an aqueous solution can be added. 50 changes. The amount of water used should be

The fourth essential component of the agent is sufficient, taking into account the invention is a corrosion inhibitor, the given percentages of the other components in amounts of 0.1 to 1.5 percent by weight, preferably 100 percent by weight,
wise from 0.8 to 1.2 percent by weight, used when using the rust remover after the. In the invention, with a variety of the invention, the agent on the rust on the upper surface of various corrosion inhibitor surfaces from which the rust is to be removed will give satisfactory results, but the amine will be carried. Application can be preferably by spraying, type-on inhibitors. The amount of brushing, spreading, rubbing or other inhibitor used is essential to the invention. B. the application are also effective and reach too high concentrations that the surface to be freed from rust is immersed in too large amounts of surface to be freed from the preparation of an amine salt or bind to hydrochloric acid in it and thereby suspended to a Vermin-. The last-mentioned working method can lead to a change in the cleaning ability. An especially preferred corrosion inhibitor, especially when removing rust from small, is that N-65 objects, such as tools, may be useful, but coconut beta-aminobutyric acid. Examples of others can be used to inhibit larger items, including sodium dichromate, propargylic acid, e.g. B. in car bodies, car chassis alcohol, propargyl sulfide and hydrazine. Likewise and similar objects. After the agent

has been applied to the rusted surface, grooves and 45 to 60 minutes in the case of heavy rusting

it is simply left in contact with it until the desired amount of rust removal has occurred is. No mechanical sanding or rubbing of the rusted surface is required, to remove the rust with the agent according to the invention. The use of such measures However, it is of course possible within the scope of the invention, because this facilitates the removal of rust and is accelerated.

After removing the rust in the desired Extent has occurred, the agent is removed from the surface according to the invention. Man can this z. B. achieve that the surface with a paper towel, a textile material or wipe it with a sponge. There is another possibility, which is preferably used by washing the agent off with water. Further options for removing the agent, such as B. with solvents, arise for the on the rusted surface. Every sheet will then washed with tap water, dried completely with a paper towel and the rust removal, the washability of the agent and the achieved protection against new rusting in the following way judged:

Rust removal

poor - little removal of moderate rust in 30 minutes;

satisfactory - equal rust removal from moderate Rust in 30 minutes as with a commercial product that contains around 18% of the Contains phosphoric acid, a cellulosic thickener and a red color;

good - better rust removal than with the mentioned commercial product;

Expert without difficulty. Awarded this classification - in addition to the good rust remover

This treatment results in a surface that is rust-free and protected against further corrosion is. No visible deposit remains on the cleaned surface, and it occurs through this cleaning in general, there is also no significant damage to the surface.

The invention is explained in more detail in the following examples. All specified parts and Percentages relate to weight, unless expressly stated otherwise.

The following working methods are used in the examples:

A smooth, shiny surface is obtained.

bad

Rust process

Iron sheets with the dimensions 10.2 × 20.4 cm made from commercially available cold-rolled steel are used for the rust tests. These sheets are rusted in a test device that is adapted to the environmental conditions. In this test device, the metal sheets ^{are repeatedly moistened for 4 1} A hours at 66 ° C. and then ^{dried at 43 ° C. for 3/4} hours. Sheets that have been treated in this way for 24 hours are said to be slightly rusted; after 48 hours of treatment, the sheets are said to be moderately rusted. Severely rusted sheet metal is obtained if the sheet metal is exposed to the effects of the external environment for more than a month.

50 Repeat the rusting process. Washability

the rust remover must be removed from a moderately rusted sheet metal after 30 minutes to be brushed off;

satisfactory - the rust remover can also be used easily remove like the above-mentioned commercial product; good - the rust remover can be cleaned with tap water and remove very little outside help; excellent - the rust remover is instantaneous

peeled off at the first contact with water.

protection

bad - immediate renewed rusting after removing the rust remover (»Flash rusting«);

satisfactory - same protective effect as with the commercial product mentioned above after repeating the rusting process for 24 hours in the test device described; good - better protective effect than the characterized commercial product after repeating the rusting process for 24 hours in the

test device described; After the trays have been cleaned, an award is made - rust formation occurs after 24 hours dry them in the air for a quarter of an hour. and then for 24 hours the direction described above is significantly lower than Resubjected to rusting process. with a slightly rusted sheet metal.

Cleaning process

There are 12 g of the agent to remove rust and protect against re-rusting applied to each of the 10.2 x 20.4 cm panels regardless of the degree of rusting.

The agent is moved on the surface of the rusted metal sheets for a few minutes at the beginning, then let it rest until you wash it off. In general, the agent is left with slight rust 15 minutes, with moderate rusting 30 minutes

example 1

Several preparations have been made to remove rust and protect against re-rusting, which essentially consists of 8% of an aqueous hydrochloric acid solution with a content of about 37% HCl, 20% citric acid, 2%. a nonionic alkylaryl polyether (surfactant), a corrosion inhibitor and a residual amount of water.

The corrosion inhibitor and its amount in each of these agents were as follows:

Agent A - 1% of an aqueous solution of a corrosion inhibitor based on an amine compound;

Mean B - 2% of the same mean as for A;

Agent C - 1% of a 50% solution of a corrosion inhibitor based on an amine compound;

Agent D - 2% of the corrosion inhibitor of C;

Agent E - 1% of an aqueous solution of N-coconut-beta-aminobutyric acid;

Mean F - 2% of the corrosion inhibitor from E.

These six agents were used to remove rust from rusted metal sheets according to the method described above Way of working used. They all gave good rust removal and good washability of the means. The means A to E also gave good protection against renewed rusting, whereas with the middle F an excellent protection against renewed rusting was achieved.

Example 2

The following formulations were made, all of which had good rust removal and a gave good protection against renewed rusting.

Agent A essentially consisted of 8% of an aqueous hydrochloric acid solution containing about 37% HCl, 20% citric acid, 2.5% of a nonionic surfactant, 2% of a 50% aqueous solution of N-coconut-beta-aminobutyric acid as a corrosion inhibitor, 6% colloidal silicon dioxide as a thickener and 60% water.

Agent B essentially consisted of 10% aqueous hydrochloric acid containing about 37% HCl, 20% citric acid, 2.5% of a nonionic surfactant, 2% of a 50% aqueous solution of N-coconut ^ beta-aminobutyric acid as a corrosion inhibitor , 6% of a kollo idalen silica as a thickener and 60 ° / a of water.

Mean CT consisted essentially of 12% one aqueous hydrochloric acid containing about 37% HCl, 20% citric acid, 2.5% of a mchtionic surface-active By means of 2% of a 50% aqueous solution of N-coconut-beta-aminobutyric acid as a corrosion inhibitor, 6% of a colloidal silica as a thickener and 58% water.

In detail, the following results were obtained with these means:

Agent A gave good to satisfactory rust removal, excellent protection against re-rusting and was considered to be in its general behavior to rate well. Agent B gave good rust removal, protection against re-rusting and was to be rated as good in his general behavior. Agent C gave excellent rust removal, a satisfactory protection against renewed rusting and was in its general behavior as easy to judge.

Example 3

The following agents for removing rust and preventing re-rusting were particularly useful good results, with agent A being the preferred embodiment of the invention.

Agent A essentially consisted of 4.48% HCl, added as an aqueous solution, 20.00% citric acid, 2.50% of a nonionic surfactant, 2.00% of a 50% aqueous solution of N-coconut beta-aminobutyric acid as a corrosion inhibitor, 6% of a colloidal silicon dioxide as Thickener, 0.14% N-octyl alcohol as an anti-foam agent and water as the remainder.

Agent B essentially consisted of 7.55% of an aqueous hydrochloric acid containing 38% HCl, 19.00% Citric acid, 2.37% isooctylphenyl-polyethoxyethanol as surfactant, 1.90% one 50% aqueous solution of N-coconut-beta-amino-

zo butyric acid as a corrosion inhibitor, 1.90% of a methyl cellulose thickener, 0.95% of a commercially available antifoam, which was a mixture of paraffin oil, fatty acid esters and silicone antifoam, and 66.33% water.

Example 4

The following preparations were made, which are also good agents for removing Rust and to protect against renewed rusting.

(A) The agent consisted essentially of 2.7% of an aqueous hydrochloric acid containing about 37% HCl, 25% citric acid, 3.0% * isooctylphenyl-polyethoxyethanol as a surface-active agent, 2% of a 50% aqueous solution of N -Coconut-beta-aminobutyric acid as a corrosion inhibitor, 2% N-octyl alcohol as an antifoam agent, 6.5Vo colloidal silicon dioxide as a thickener and water as the remainder.

(B) The agent consisted essentially of 21.5% of an aqueous hydrochloric acid containing about 37% HCl, 10.0% of citric acid, 0.5% of glycerol monolaurate as surfactant, 2.0% of a 50% aqueous solution of N-coconut beta-aminobutyric acid as a corrosion inhibitor, 0.15% of a silicone antifoam, 6.0% colloidal silicon dioxide as a thickener and water as the remainder.
(C) The agent consisted essentially of 32.4% of an aqueous hydrochloric acid containing about 37% HCl, 7.5% citric acid, 5.0% polyoxyethylene sorbitol laurate surfactant, 1.5% of a 50% aqueous solution of N-coconut-beta-aminobutyric acid as a corrosion inhibitor, 0.15% N-octyl alcohol as an antifoam agent, 6.0% colloidal silicon dioxide as a thickener and water as the remainder.

409518/380

Claims (2)

1 2 From patent no. 49119 of the Office for Patent Claims: Inventions and Patents in East Berlin, it is known to use citric acid in a mixture with alkali or 1. Means for removing rust and for ammonium hydroxide and possibly mineral protection against renewed rusting, the hydrochloric acid, 5 acids, such as hydrochloric acid, for derusting vascular citric acid, a corrosion inhibitor and systems to use, whereby only minimal amounts of water contain, thereby Characterized by citric acid used in a low concentration so that it is essentially composed of 1 to 12Ge. Such agents have only one percent by weight HC ^ 7.5 to 25 percent by weight of low effectiveness and usually require the lemon jure, ~ 075 "to 5 percent by weight of an io application of higher temperatures and long surfactants, 0.5 to 1.5 percent by weight Periods for a satisfactory removal of the percent of a corrosion inhibitor, 0 to 6.5 rust. weight percent of a thickener, 0 to In the USA. Patent 2,981,633 is a ver 0.2 percent by weight of an anti-foaming agent go to the pretreatment of ferrous metals that and consists of water as a residual component 15 should be coated with enamel afterwards, 2. Means according to claim 1, characterized thereby. In this process, aqueous Zizeichnet is used to pickle the ferrous metals, essentially consisting of 3 to 5 acidic acids, optionally mixed with mineral percent by weight HCl, 17.5 to 20 percent by weight acids.
Citric acid, 2 to 2.5 percent by weight of a corrosion inhibitor disclosed in U.S. Patent 3,242,093 is a nonionic surfactant 0.8 to 20 percent for rust removal and 1.2 percent by weight corrosion inhibitor comprising diammonium citrate, sodium bicarbonate Based on an amine, 5.5 to 6.5 percent by weight, citric acid and a non-ionic upper percentage of a thickener based on surface-active agent. This agent is a loidal silicon dioxide, 0.1 to 0.2 weight per cent, which must be dissolved in water before it can be used as an antifoam agent and from water as a protective agent.
Remainder exists. U.S. Patent 2450861 deals with the removal of deposits, such as scale deposits in steam boilers, and shows the loading use of an amine as a corrosion inhibitor in one 30 means containing hydrochloric acid. From the USA patent specification 2,558,167 a gel- The removal of rust has been a problem since the beginning of like or paste-like means for removing the Iron Age, since since then it has been known from rust and against renewed rusting that there is a desire to remove surfaces of iron and phosphoric acid and / or organic acids, such as Zi-iron alloys to rid them of rust, to make them tronic acid, and to protect them as a thickening agent, and to protect their appearance and use- carboxyalkylcellulose,
to improve availability. Although for this purpose in the subject matter of the present invention a co-over the many years numerous methods and pouches for removing rust and for protection against preparations for removing rust have been found- renewed rusting, the hydrochloric acid, citric acid, one the, The problem of rust protection and the corrosion inhibitor and water contained and thereby rust removal still exists today. is characterized in that it consists essentially of 1 to A cleaning process requires several 12 percent by weight HCl, 7.5 to 25 percent by weight Factors to be taken into account before a befriedi- citric acid, 0.5 to 5 percent by weight of an obergende System can be developed. So it is B. surfactant, 0.5 to 1.5 weight percent desirable to have a process which is not a corrosion inhibitor, 0 to 6.5 weight percent associated with the development of toxic gases and inadequate thickening agents, 0 to 0.2 weight loss odors. In addition, percent consists of an antifoam agent and water as the desire that only residual constituents exist through the cleaning process. the rust is removed from the surface and that it is surprising that this agent is free from the surface itself and any 50 present is the main disadvantage of the known means Paint or other covering material undamaged and compared to the best commercial products stay. Furthermore, the cleaning method should not be of this kind by superiority in terms of to visible deposits on the surface, the rust removal, the washability of the rust the rust has been removed. Another means of protection and protection against re-rusting From the point of view of importance is the lightness, 55 distinguishes itself. with which such a rust preventive on the inside to be used according to the invention Can apply surface and the contact between amounts of hydrochloric acid from 1 to 12 percent by weight see the means and the grate sustaining the preparation are 3 to 5 percent by weight the can be. Another point of view that has preferred amounts. These quantities are 100% An important role is to calculate the requirement for the 60 HCl, although usually the mean Rust remover that he has the cleaned surface against an aqueous hydrogen chloride solution in the Hanweiteres Rusting protects. If the product is added to the commonly available form, mine is to be used, so also plays the The water added in this way sets the see the product play an essential role. Last proportion of water, regardless of the In the end, however, the main requirement is that hydrochloric acid must be added in order to achieve the total quick, effective and careful removal of the preparation to bring it to 100%. In connection Rust by such a means and such a deal with the concentration of the rust remover on salt driving is achieved. acid, it was found that the cleaning speed