DE2137052A1 - Aluminium surface treatment - to form strongly adhering anticorrosion layer of org cpd - Google Patents

Abstract

A strongly adherent layer of an org. cpd. (I) contg. >8C and having a functional grp. which reacts with an alcohol is formed on Al. A layer of hydrated, amorphous active aluminium oxide is first formed as an integral part of the surface of the Al this is then dipped in (I) and reacted with an alcohol forming a water impervious layer, (I) are chosen carboxylic, phosphonic, organic phosphorus, and phosphonic acids opt. S substd., isodiiso-, isothio- and diisothiocyanates, ketenes, ethylenic derivs. of formula: Where X is O, NH or S, esters of the type RCOOR', organic sulphonates, sulphates, and carbonates or sulphonic acids.

Description

Process for modifying aluminum surfaces that modified Aluminum surfaces and provided with these aluminum products, such as laminates The present invention relates to aluminum objects that adhere very firmly have organic films on their surface, and it also relates to improved ones Process for the chemical conversion of aluminum surfaces in order to create them new and better chemical, physical, mechanical and electrical properties and also to give it a more tasteful appearance, thereby increasing the technical utility value and the economic exploitation of aluminum for the most diverse Applications is increased.

The term "aluminum" used in this description of the invention is said to be both high-purity aluminum and the various technical Grades of aluminum and aluminum-based alloys and composite materials in which the aluminum is in a suitable form (e.g. in the form of a coating, threads, powder, etc.) is used as an element of the composite material.

It is known to use an anodic oxidation treatment in aluminum subject to (i.e., anodized) the manner of treating the aluminum component as Anode switches and conducts a direct current or alternating current through the Slektrolytan. A typical anodizing bath is e.g.

a solohes that contains about 10 to 20 percent by weight of sulfuric acid. The operating temperature can be between 20 and 22.2 ° C (68-72 ° F), whereby one when using direct current, a voltage of 5 to 20 volts applies, while the current density is about 1.1 to 1.61 amperes / dm2 (10-15 amperes per square foot) can and the thickness of the oxide film by the duration of the anodic oxidation treatment is determined.

Albeit by such an anodizing treatment for aluminum in general a satisfactory overall corrosion resistance is imparted, so is this treatment but connected with various nightmares. One of these drawbacks is the precise monitoring of the operating conditions, which is necessary to the formation a solid coating to achieve with certainty. There is a second disadvantage that during anodizing in technical electrolytes, such as sulfuric acid, a certain Nelgung for the formation of pores occurs in the oxide layer, namely due to the constant dissolving action of the acid during of education of the layer, the pore size obviously depending on the oxidation potential. For example, it has been found that in a. consisting of 15% sulfuric acid Bath pore diameters of approximately 150 Angstrom units can be obtained. The number the pores can, as was determined, up to about 400 x .109 pores per 6.45 c 2 (square inch) anode area, and the volume occupied by the pores can be, such as was found to be about 5 to 15 volume percent of the total volume of the film turn off. Pores are of course undesirable because they allow in small ones Corrosion occurs in areas and deep pits of rust arise from this, such as on the ones on the aluminum surface in the form of a fitting or white spots occurring corrosion by-products can be seen, which affects the quality of the surface finishing adversely affect.

A third disadvantage, that applied by anodic oxidation treatment The obvious thing is that these show a certain tendency to be brittle, especially in those cases where hard coatings; n sulfuric acid or oxalic acid be generated at or below room temperature. The hardness of the films is that of Similar to corundum, and such filaments are subject to the formation of hairline cracks, on the one hand due to the differences in the thermal expansion of the oxide coating uiid of the aluminum substrate on the other hand or due to the bending stress during use.

A fourth disadvantage is that the production of qualitative @ high quality anodized oxide coating is expensive.

Another disadvantage is the discoloration and darkening to see that occur with aluminum alloys, the copper, iron, silicon and other elements which form colored oxides with aluminum oxide.

In order to avoid the above-mentioned disadvantages, which the conventionally manufactured, Adhering to anodically applied oxide coatings and eliminating them are numerous methods has been proposed. A method that has acquired a certain importance has become known as the "sealing process", whereby the term "sealing" ("sealing") to indicate the closing of the pores in the oxide coating that takes place to the moisture and the impurities of the surrounding medium To prevent entry into the coating and thus the build-up of tiny electrolytic cells to prevent that to an intensification of the degree of corrosion in certain limited Areas can contribute. This method consists of doing it anodically oxidized aluminum from a treatment by immersion in boiling hot water subjects or exposes it to water vapor to convert an aluminum oxide monchydrate into to form the pores, as a result of which a 10 to 2O% increase in volume in the Movie enters. One can assume that the pores from the environment as a result of this treatment essentially to be completed. The aluminum oxide monohydrate formed has a boehmite crystal lattice. i.e. it has a crystalline structure. This However, the type of treatment does not always give adequate protection to the coating against corrosion.

Attempts have been made to prevent the use of sealing wheels try out inorganic and / or organic chemical compounds, e.g. Nickelac @ tat, dichro @ ate, molybdates, chlorinated paraffin and the like, but these too Chemical compounds have inherent disadvantages in that they tend to adversely affect the color of the alumina, causing the the original color gloss of the aluminum is impaired.

It has now become an economical method of making a large number of diverse aluminum products with improved surface modification found.

According to one embodiment of the present invention, durable, chemically firmly bonded organic films or coatings on aluminum surfaces by applying a simple surface pre-processing step prior to application of the organic film can be produced, whereby the firm bond with ordinary Temperature or at temperatures other than room temperature is.

The invention will now be based on the following description of the exemplary embodiments and the accompanying drawings will be explained in more detail.

Figure 1 is the reproduction of an electron micrograph magnified 200,000 times, which is one according to the teachings of the present invention reproduces organic film bonded to the aluminum.

FIG. 2 shows an aluminum panel which is treated in three sections has been, with one of the sections according to the teachings of the present invention was treated.

FIG. 3 shows a diagram for evaluating the corrosion behavior with the help of which one can determine the corrosion resistance of treated aluminum surfaces can judge numerically.

In a broad sense, the present invention provides improved aluminum surfaces, which contain an organic film chemically bonded to them, which occurs at the bond boundary @@@ che from the reaction product of an organic compound with an active, hydrated, amorphous layer of aluminum oxide, which forms a whole with the aluminum. The organic compound making up the film has at least 8 carbon atoms on and is characterized by a functional group starting with aliphatic Alcohols can react, while the active, hydrated aluminum oxide layer has the property with the functional group of the organic compound to be able to react like an alcohol. The reaction product that is formed is further distinguished by the fact that it is essentially insoluble in water.

In order to take advantage of the advantageous new results of the present invention To be able to do so, two requirements should be met: (1) The aluminum surface should a residual adhesive, alorphous layer of an active, essentially non-porous Have aluminum oxide hydrate, which when reacted with certain organic Compounds behave like an aliphatic alcohol; and (2) those on the surface The organic connection to be applied should be one whose functional group with an aliphatic alcohol - and consequently with the active hydrate - to re @ ye publisher.

For the purposes of the present invention, the active, amorphous Aluminum oxide hydrate considered as having alcohol-like properties, although the oxide is actually inorganic in nature.

However, a bond ar the aforementioned alcohol theory only insofar exist as it illustrates that the amorphous and with the aluminum surface a whole hydrate of alumina forming the property of reactivity with the organic coating-forming compound for the purpose of forming a chemical Has binding with the same.

The active, amorphous layer of hydrated alumina becomes in such a way that you first have a firmly adhering "barrier layer" on the Aluminum surface forms, and the hydrate is immediately followed by reaction i formed with water. The barrier layer represents a precursor to the formation of the conventional one anodically applied oxidation layer. Their formation and behavior are Has been the subject of extensive investigations through numerous edited (cf. on this M.S. Hunter and P. Fowle, "Determination of the Barrier Layer Thickness of Anodic Oxide Coatings "in Journal of the Electrochemical Society Volume 101 (9) pages 481-485 dated September 1954).

.After the formation of the barrier layer, which is essentially is not porous, the further build-up of the layer thickness i @ generally has the formation a po @@ sen oxide layer result, due to the solution @ @ @ @ @ @ @ @ medium effect the electrolyte in which it was formed, the extent to which it was formed the porous and crystalline Layer forms, a puncture of time, the electrolyte composition and concentration, the bath temperature and the applied Tension is. Is is - depending on the choice of the aforementioned conditions - possible, to form a relatively thick porous oxide coating in a few minutes, How was found, shows the crystalline oxide layer of the anodically applied coatings of this type no tendency to interact with the functional groups of organic compounds, which are proposed in the context of the present invention to react. In those cases, however, in which the barrier layer has been formed and one for it ensures that their surface forms a hydrate. In the presence of water, becomes a very active, amorphous layer created. those with the selected organic compound chemically reacts.

An aluminum surface that has a natural oxide coating, does not behave that way.

On the organic compounds, the few carbon atoms have and have functional groups that sit aliphatic alcohols capable of reacting include carboxylic acids, acid anhydrides, phosphinic acids. organic acid phosphates and acid phosphites including those in which at least one @oxygen atom is replaced by sulfur; also organic isocyanates, diisocyanates, isothiocyanates and diisothiocyanates; Ketenes, ethylene derivatives including compounds sit one. three-membered heterocyclic ring system, such as ethylene oxide derivatives, Ethylene imine derivatives and ethylene sulfide derivatives; Esters of the formula type RCOOR ', organic Sulfonates, organic sulfates, sulfinic acids, organic carbonates and the like who.

Examples of carboxylic acid which can be used are those of the fatty acid type which can usually be represented by the formulas RCO2H and R (CO2H) 2, and their anhydrides of the general formula (RCO) 2O. Examples of phosphinic acids are those of the general formula R2P (O) OH. The acid phosphates and phosphites include the phosphates of the formulas (RO) 2P (O) OH and ROP (O) (OH) 2, the phosphites of the formulas (RO) 2POH and ROP (OH) 2, the thiophosphates of the formulas (RO ) 2P (S) OH and ROP (S) (OH) 2, as well as the thiophospnites of the formulas (RS) 2POH and RSP (OH) 2 besides others. The organic isocyanates in question correspond to the general formula RNCO and the diisocyanates correspond to the general formula R (NCO) 2. The isothiocyanates have the general formula RNCS and the diisothiocyanates have the general formula R (NCS) 2. The ketenes in question correspond to the general formula RCH-CO and the ethylene derivatives to the general heterocyclic ring formula in which XO can be (ethylene oxide, e.g. oxirane) or NH (ethyleneimine, e.g. aziridine) or S (ethylene sulfide, e.g.

Thiirane), while the esters in question are generally characterized by the formula RCOOR '. The sulmonates correspond to the formula and the sulfates of the formula O RO - S = O.

OH The sulfinic acids in question have the general formula RSOOM. As usable organic carbonate. are those of the general formula to cite.

What the radicals R (or R ') in the for the aforementioned compounds As far as given formulas are concerned, they can be alkyl, aralkyl, aryl or alkaryl groups represent, wherein the compounds are generally of the type of alkyl compounds belong. Unsaturated alkyl compounds are particularly recommended for generation of corrosion-resistant base films because of their tendency Polymerize oxidation with the formation of a tough resin coating.

Prong method of generating the active. @morph, hydrated Layer of aluminum oxide before the formation of a chemically bound organic Film consists in immersing the aluminum in dilute acid, e.g.

20 volume percent hydrochloric acid or phosphoric acid, right up to the aluminum surface gas evolution begins.

As the barrier layer forms, its surface reacts with the existing water to form amorphous hydrate. Another method of generation of the active, amorphous hydrate is an electrochemical method, and it is best in a very short anodic treatment (e.g. usually lasting less than t minute) in an aqueous solution of a mineral acid, wi @ sulfuric acid, Phosphoric acid or @ @@ mix the same. Do one of these methods the amorphous hydrate has been formed, the activated aluminum surface becomes after rinsing with an organic compound (e.g. in a alcoholic-aqueous Solution of acidic stearyl phosphate dipped), whose functional group reacts with the hydrate in a manner analogous to how it reacts with an aliphatic alcohol would react, making it relatively water-insoluble Forming product at the interface, which is a strong chemical bond between the overlying organic film and the aluminum substrate (nachoem the coating is ge @@ ocknet @orden, for example by blowing cold air on).

Another method consists in forming the active, amorphous hydrate layer in a single operation on the aluminum in an electrolyte, which is obtained from an aqueous bath, e.g. an ethanolic-aqueous solution, which contains an effective amount of a dispersed acidic stearyl phosphate, There are indications that the layer of active hydrate of alumina is polymorphic in character and conforms to the following structural formula: However, the layer need not consist entirely of aluminum hydrate. For example, depending on the acids that are used to produce the active aluminum oxide hydrate, »other ions, such as chromate and oil. or phosphate ions, may be present in the layer as long as there are only a few places in the layer of the active, amorphous hydrate of aluminum oxide which are sufficient to bring about the desired bond with the applied organic film. The term "active, amorphous hydrate of aluminum oxide" is therefore intended to denote both the active hydrate as such and an active hydrate diluted by the presence of other amorphous inorganic compounds, such as chromates and or or phosphates.

The chemical bond can be brought about pretty quickly once by immersing the treated aluminum surface in suitable solutions that contain an equal amount of the organic compound as in an alcoholic compound Solution of acid @ lauryl phosphate (e.g. with a content of 5 U per liter), or on the other hand, by applying the appropriate organic compound directly onto the treated surface, e.g. by painting with α-naphthyl isocyanate or with corn oil. In those cases where e.g.

Corn oil uses wi @ d, after the formation of the chemical bond, a heat treatment (e.g. a 15 minute treatment at 129.4 ° C or 265 ° F) can be followed to harden the oxidation and polymerization of the excess unsaturated acid to accomplish a tough resin coating. As already mentioned above, however, the reaction can also be carried out as a one-step operation, for example in such a way that the aluminum - connected as an anode - is treated in a solvent-water-electrolyte solution containing an acidic alkyl phosphate. Since not much organic compound is needed to cover the aluminum surface, dilute solutions can be used. As an example of the type of reaction which - as can be assumed - occur in the context of the present invention between representative functional groups of organic compounds and the amorphous, hydrated aluminum oxide for the purpose of forming the reaction product which is essentially insoluble in water The following are listed: Chemical bond of the ester type, formed by condensation reactions Fatty acids of the type RCO2H: Alkyl phosphates of the types (RO) 2P (O) OH and ROP (O) (OH) 2: Chamic bond of the ether type, formed by condensation reactions. Alkyl phosphites of the types (RO) 2POH and ROP (OH) 2: Chemical bond of the ester type, formed by addition reactions Isocyanates of the type RNCO: Keten @ des type @ RCH-CO: Chemical bond of the ether type, formed by addition reactions. Ethyl oxide derivatives of the type Ethylenimine derivatives of the type Ethylene sulfide derivatives of the type Chemical bond of the ester type, formed by transesterification reactions Esters of the type RCOOR ': Further additional formulations are the following: Alkylsulfonate @es type: Aryl sulfonates of the type: Alkyl sulfates of the type: As studies have shown, in general compounds that could be expected to form protective films on aluminum were as effective as the group R or the remainder R (e.g.

the alkyl group) little ate had 8 carbon atoms (i.e. when they Compounds that are either insoluble or only slightly soluble in water are.

Overlays or films that have been applied with connections, the Although they have essentially the same group R, they do have functional groups contained, from dunes could not be expected that they would with the active, amorphous Hydrate will react showed a lower corrosion resistance, if the treated aluminum panels test for this property by means of the acid salt spray test, known as the "CASS" test. This test forms the generally accepted standard method for assessing corrosion resistance of treated aluminum surfaces, and the term "CASS" is an abbreviation from the first letters of the exact name "copperaccelerated acetic acid salt spray test "as adopted in ASTM regulation 368-64T has been.

The method used to assess corrosion resistance is similar to the ASTM method described in the Committ @ e Report of 1953 (Proc. At the. 800

Testing Mat. 53, 265, 1955) has been published in detail is. The valuable numbering of the corrosion behavior is made by calculation the percentage weight of the area that is damaged and @@ read the rating number from the conversion curve shown in Figure).

When performing such an assessment, the percentage Defective area determined by comparing tactile pattern @ with the values from standard diagrams, which are taken from "CASS" rating numbers and a rating scale that starts from 0 up to 10 included. As a consideration of FIG. 3 reveals, corresponds for example, a "CASS" score of 7 of a weighed percentage chess-like area of 0.5, and a "CASS" rating of 5 corresponds to a weighed percentage defective area of 2.0. If you put the percentage weighted defective Area, so a "CASS" rating of 7 shows fourfold superiority against a pattern that can only be assessed with the "CASS" number 5.

In those cases in which this description of the invention organic Compounds falling within the scope of the invention as coatings thereon Compounds are compared that are outside the scope of the invention 3 hour "CASS" evaluations applied to the execution of the determination as determined it was found that 3 hour tests are sufficient for the assessment. Should the long-term effectiveness of the coating are assessed, 17-hour "CASS" tests are carried out, It should be noted that the 17-hour test is a very tough test represents.

To assess the coatings, aluminum panels with a size of 50.8 mm x 152.4 mm (2 x 6 ") and 101.6 mm x 152.4 mm (4 x 6") and a thickness of approximately 3.175 mm (1/8 ") used. Among the aluminum alloys used, for example include the alloys with the numbers 1100, 2025, 3003, 5005, 5557, 6061, 6063, 7075 and also aluminum as such.

Examples of organic functional groups that have a reactive behavior show as required by the teaching of the present invention are in the following Table 1 compared to those groups that have a does not show such responsiveness, with the "CASS" test as one of the parameters was used to carry out the comparison.

Table 1 Classification of the functional organic groups according to the corrosion resistance they cause "CASS" - corro-organic compound evaluation (and functional number constant group) Formula (+ 0.5) strength 1. Acid lauryl phosphate (acidic -primary Phosphate) CH3 (CH2) 11OP (O) (OH) 2 8.5 good 2. Dilauryl phosphite (secondary phosphite) [CH3 (CH2) 11O] 2POH 7.5 good 3. Metoyl stearate (simple ester) CH3 (CH2) 16C ( O) OCH3 8.5 good 4. Carnauba wax +) (ester mixture) 7.5 good 5. n-octadecyl isocyanate (alkyl isocyanate) CH3 (CH2) 17HCO 8.5 good 6. α-naphthyl isocyanate (aryl isocyanate) C10H7NCO 7.0 good 7 Lauric acid (monocarboxylic acid) CH3 (CH2) 10C (O) OH 7.0 good 8. Stearic anhydride (acid @ anhydride) [CH3 (CH2) 16CO] 2O 7.5 good 9. Diphenylphosphinic acid (phosphinic acid) (C6H5) 2P (O) OH 7.0 good 10. 1,2-poxootade- & - C, ""'6 ca "(oxirane) CH3 (C) 15 11. Dilauryl carbonate (acid @ carbonate) [CH3 (CH2) 11O] 2CO 7.2 good A. Lauryl alcohol (alcohol) CH3 (CH2) 10CH2OH 4.5 low B. Trilauryl phosphate (tertiary phosphate) [CH3 (CH2) 11O] 3P (O) 4.0 low C. 2-Undecanone (ketone) CH3 (CH2) 8C (O) CH3 3.5 low D. Laurylaldehyde (aldehyde) CH3 (CH2) 10C (O) H 3.5 low E. Lauronitrile (Nitrile) CH3 (CH2) 10CN 3.5 low F. Laurylamine (amine) CH3 (CH2) 10CH2NH2 3.5 low G. Laurylamide (amide) CH3 (CH2) 10C (O) NH2 3.0 low H. 1- Octadecene (unsaturated hydrocarbon) CH3 (CH2) 15-CH-CH2 3.0 low I. Tridedecylmethylammonium chloride (quaternary ammonium salt) [CH3 (CH2) 10CH2] 3N + CH3Cl 3.0 low +) Mixture of esters of normal alcohols with fatty acids, which have an even number of carbon atoms between 24 and 34.

Aluminum alloy flats were placed on one side with the buffing wheel polished and after pre-cleaning in a sulfuric acid-phosphoric acid @ anodizing bath (about 15 percent by volume sulfuric acid and 15 percent by volume Phosphoric acid) anodically activated. The amorphous alumina hydrate became after about 15 seconds long anodizing treatment at 29.4 ° C (85 ° @) at a voltage of 12 volts. In the ailina, the aluminum plates were then immersed in an ethanol-water solution for 5 minutes (25 percent by volume ethanol and 75% by volume water) immersed that in Lözung either 3 g of the solid organic compound per liter or 5 ml of an organic Compound, which was liquid, contained per liter. Those aluminum plates that have not been treated according to the working method specified above explained individually in the examples below @ n.

As can be seen from the table, those under No. 1 up to 11 mentioned pre-commitments relatively high "CASS" rating numbers and good corrosion resistance, while the compounds listed under A to I. extremely low "CASS" rating numbers and generally low corrosion resistance showing the differences in the behavior of the two groups of compounds must obviously be attributed to the fact that they differ from each other in their functional Differentiate groups. All approaches suggest that the amorphous aluminum oxide hydrate chemically reacts selectively with the functional groups of compounds 1 to 11, this, however, with the functional groups of the compounds A to I obviously do not.

The following examples are intended to illustrate the various embodiments explain the invention in more detail.

Test 1A 3b stearyl acid phosphate were dissolved in 250 ml of ethanol at 62.8 ° C (145 ° F) and made up to 1 liter of solution with water. One polished Aluminum plate (50.8 mm wide and 152.4 mm long) made from alloy No. 6063 existed, was pre-cleaned in the following way: (1) degreasing with trichlorethylene cones; (2) Immerse in a 79.4 ° C (175 ° F) alkaline cleaning solution for 90 seconds (alkaline cleaning agent with a retarding effect, the basic alkali salts, contains surface-active substances and emulsifiers); (3) Flush for 60 seconds in 48.90 C (120 ° F) water; (4) immersion in an acid solution for 15 seconds, which contains 50 percent by volume nitric acid; and (5) rinse in for 30 seconds approximately 23.9 ° C (75 ° F) warm water. After cleaning, di. Plate 15 seconds with direct current of 11 to 12 volts at a current density of 1.61 amps / dm2 (15 amps / sq.ft.) in a solution containing 15 percent by volume sulfuric acid and 15 percent by volume phosphoric acid , anodized at 26.7 ° C (80 ° F) and then at 23.90C (75 ° F) for 30 seconds warm tap water and then distilled in 25.60C (78 ° F) for 15 seconds Rinsed with water. This treatment provided a test adherent, essentially non-porous Layer of an active, amorphous aluminum oxide hydrate on the surface.

The plate with the amorphous oxide layer was then 5 minutes in a aqueous bath containing acid stearyl phosphate, immersed, and then the Surface rinsed and dried with about 25.6 ° C (78 ° F) warm, circulating air, The plate with the so organic modified surface was then subjected to the "CASS" test in the medium prescribed for this for 3 hours. A "CASS" rating of 8.5 was determined for a cleaned aluminum plate same size and composition, for comparison purposes by 15 seconds long Anodic treatment had been anodized to make the above mentioned active amorphous frying layer after a three-hour "CASS" test was only able to achieve a rating of 2.0 can be determined.

Test 1B Similar experiments were carried out with the compounds acid lauryl phosphate, Dilauryl phosphite, lauric acid, capric acid, myristic acid and diphenylphosphinic acid performed using the same conditions and the same concentrations as were used in test 1A. After a "CASS" test carried out for 3 hours The following “CASS” rating numbers were measured: Table 2 Compound “CASS” rating number acid lauryl phosphate 8.5 dilauryl phosphite 7.5 lauric acid 7.0 capric acid 6.5 myristic acid 6.5 palmitic acid 6.5 diphenylphosphinic acid 7.0 For comparison purposes A cleaned aluminum plate of the same size and composition became 15 seconds at approximately 26.7 ° C (80 ° F) in an anodizing bath containing 15 volume percent sulfuric acid and 15 percent by volume phosphoric acid, at 11 to 12 volts and current density of 1.61 amps / dm2 (15 amperes per square foot) @ anodized. For them it was in one "CASS" test carried out for 3 hours gave a "CASS" rating number of 2.0.

Example 2 Similar to Example 1, a polished aluminum plate was prepared (50.8 mm wide and 152.4 mm long), which consisted of Alloy No. 6063, in the following Pre-cleaned manner: (1) degreasing in trichlorethylene vapors; (2) 90 seconds long Immersion in a 79.4 ° C (175 ° F) was @ e alkaline cleaning solution; (3) 60 seconds long rinse with 48.9 ° C (120 ° F) water; (4) Immersion for 15 seconds in an acid solution containing 50 volume percent nitric acid; and (5) 30 seconds long rinsing with 23.9 ° C (75 ° F) warm water. After cleaning, the flatten became 15 seconds at a current density of 1.61 amps / dm2 (15 amps / sq.ft.) In a solution, which contained 15 percent by volume sulfuric acid and 15 percent by volume phosphoric acid, anodized at about 26.7 ° C (80 ° F) and then in 23.9 ° C (75 ° F) for 30 seconds Tap water and in 25.6 ° C (78 ° F) distilled water for 15 seconds flushed.

This treatment provided a firmly adherent, essentially non-porous one Layer of amorphous aluminum oxide hydrate on the surface, after drying became the flatten with the amorphous oxide layer with liquid n-octadecyl isocyanate coated. Excess isocyanate was removed by immersing the Plate removed in distilled water with occasional stirring. After a "CASS" test carried out for 3 hours, the panel had the good corrosion rating number 8.2 on.

Example 3 Linseed oil is known to be widely used drying oil that is used in paints and varnishes. The oil consists predominantly from a mixture of glyceryl esters of linoleic acid and linolenic acid, which - if if they are exposed to air - they oxidize and polymerize to form a tough resinous coating. This example demonstrates that the tr @@ kn @ n @ n @ ding oils, such as linseed oil, can easily be added can be brought to leave a hard resin coating if they are after the teachings of the invention are applied. Such coatings are of technical importance as electrical insulation on aluminum wire and as firmly adhering base coats for the subsequent paring application.

A polished aluminum plate measuring 50.8 x 152.4 - »the one from the Alloy No. 5557 was cleaned as described in Example 1 and Anodized in a sulfuric acid-phosphoric acid solution for 15 seconds. After drying a thin film of boiled linseed oil was applied to the active surface using a fine cloth @ s spread on. In an analogous way, a two - @@ aluminum plate, the 3 minute land had been anodized, uiid a third plate that was only degreased was also smeared @ with the boiled linseed oil.

To illustrate that the anorphic, hydrated Oxide surface A fourth flatten was created by simply immersing it in acid painted in an agereindgte iqer manner after the plate has been placed in a 25.6 ° C (78 ° F) warm, 20-percent by volume phosphoric acid solution had been immersed until uniform Gas evolution occurred which took about 2 1/2 minutes. All the plates were rinsed with distilled water and dried, the linseed oil was spread on became. After painting, all 4 panels were left in the air for 25 minutes Chopped 135 ° C (275 ° F). one end of each plate then became a rod of UM The plates were bent 25.4 mm in diameter and then left for 17 hours subjected to the conditions prescribed for the "CASS" test. lin.

The following table contains a summary of the corrosion results. For purposes of comparison, a result has also been included in this table, that with a cleaned plate of the same size and the same alloy composition was obtained, this plate 20 minutes 11 in the sulfuric acid-phosphoric acid solution anodized and sealed in boiling distilled water for 15 minutes.

Table 5 Taken before applying the flax "CASS" rating oil Surface number plate treatment; flat curved no. face face 1 cleaned and anodized for 15 seconds 9.5 8.5 2 cleaned and for 3 minutes, anodized X, 0 0S5 3 only steam-degreased o, 6 0.6 4 anodized for 20 minutes and water-sealed -not treated with linseed oil 7.5 5.5 The above Results confirm the important role played by the amorphous hydrate layer of aluminum oxide in the production of the firmly bonded organic films on the aluminum according to the Teaching of the present invention plays. As already mentioned, it arises where the hydrated barrier layer has been formed, a very active amorphous oxide, which chemically reacts with the selected organic compounds as it does the The 15 second anodizing treatment that the plate 1 has undergone is illustrated.

On the other hand, has a more advanced anodizing treatment after formation the barrier layer results in the formation of a porous oxide layer, which - as stated - is not reactive in the same way as the 3-minute anodizing treatment illustrates what the plate 2 has undergone. Plate 3, before application The linseed had only been degreased by steam, showed only low evaluation numbers (0.6) in the "CASS" test. A plate that had been cleaned and dipped in acid in order to produce an active layer of amorphous aluminum oxide hydrates in the "CASS" test a rating number 4.5 in the flat part of the surface and one of *, 2 in the curved Y1-ch part and was superior to both plate 2 and plate 3.

As from a comparison of the corrosion rating numbers of the planes and the curved surface parts of each individual plate can be seen the plate with the short anodizing treatment (plate 1) has a resin coating of very high good flexural strength. Plate 4, which is anodized aluminum in the usual way is equivalent to, shows a decrease in "CASS" rating numbers from 7.5 to 5.5 (which is an increase in the percentage weighted defective area of 0.3 to 1.5 at the bent points and thus a five-fold increase in the percentage weighed damaged areas). Plate 1, on the other hand, shows a Decrease in the "CASS" test scores from 9.5 to only 8.5 on the bent part, which proves that the coating according to the invention from the polymerized linseed oil is solid is bound to the aluminum substrate, so at the same time also has good flexural strength One advantage of working with linseed oil is that, after the reaction product formed with the amorphous hydrate has become so firmly bound Base coat and then cure at 135 ° C (275 ° F) is to apply further layers by simply dipping them in linseed oil and hardening them can be and you can build coverings of any desired thickness, because that in addition The linseed oil applied is compatible with the base coat.

This working technique can also apply to other types of unsaturated aliphatic carboxylic acid esters such as quinine wood oil, oiticica oil, soybean oil and the like. be applied.

fleisiel 4 This example illustrates how organic compounds ester type can be used to modify an aluminum surface, to improve their corrosion resistance.

Test 4A A polished aluminum plate measuring 50.8 x 152.4 mm, which consisted of alloy no. 6063. was cleaned as described in Example 1, and then one half of the plate was exposed to a current density for 15 seconds from 1.61 amps / dm@ (15 amps / sq.ft.) and 11 to 12 volts in a sulfuric acid-phosphoric acid bath, containing 15 percent by volume of each acid, anodized. It became an active amorphous aluminum oxide hydrate obtained, which is then rinsed in @distilled water became. After drying, carnauba wax was applied to both the anodized surface and the also on the cleaned surface of the plate by brushing it with a cotton cloth applied.

The carnauba wax consists of a mixture of esters of normal alcohols with fatty acids that have an even number of carbon atoms between 24 and 34. For one type of carnauba wax, a fatty acid ester of carnaubyl alcohol is the Formula C24H49OH an illustrative example. This ester belongs to the esters of general type RCOOR '. Since carnauba wax is solid at normal temperature, the wax and plate are heated to 82.2 ° C (180 ° F) prior to application. To Aird applying the plate for 3 hours under the conditions that the "CASS" test prescribes suspended. It became a corrosion rating number of 8.0 for that Part of the plate determined which contained the amorphous, hydrated oxide. In contrast for this purpose, the part of the plate that was cleaned but not activated gave a "CASS" rating of 5.0.

Test 4B In this experiment, methyl stearate, known to be the ester the stearic acid with methyl alcohol, used to make the surface of aluminum organic to modify. A plate of aluminum alloy No. 6063, size 50.8 x 152.4 mm was cleaned and put in sulfuric acid-phosphoric acid solution, as in example 1 described, anodized. The plate with the amorphous oxide hydrate surface was then immersed for 5 minutes in an ethanol solution containing 3 g of methyl stearate per liter. After the immersion treatment, the plate was heated to 149 ° C (300 ° F) without rinsing it. hot, circulating air and then a 3 hour "CASS" test subject to the conditions prescribed for this purpose. Ea became a "CASS" rating number 8.5 determined. In contrast, another aluminum plate showed the same size and alloy composition treated in the same way with the Modification that the panel had not been anodized, the low "CASS" rating 2.5.

Test 4C A transesterification reaction with dilauryl carbonate, which has the formula [CH3 (CH2) 11O] 2CO. The liquid dilauryl carbonate only one half of the hydrated aluminum surface was on the plate had, applied by brushing with a Bau @ wolltuch. After applying the plate was treated with hot, circulating air for 45 seconds, to initiate the reaction, after which the plate was turned on for 3 hours "CASS" test subject to prescribed conditions. Rs became the "CASS" good rating number 7.2 measured on the treated surface.

The untreated half had only the low "CASS" rating 3.0 on.

Example 5 This example illustrates the usefulness of the application of electrolytic methods for creating a corrosion-resistant alkyl phosphate conversion coating in a. one-step operation.

Effective amounts of 3 g of lauryl acid phosphate and 3 g of stearyl acid phosphate were dissolved in 600 μl of ethanol, and the whole thing became a 2-liter dispersion with water filled up. A polished and steam-degreased aluminum plate measuring 50.8 x 152.4 mm, which consisted of Alloy No. 6063, underwent an alkaline cleaning subjected by immersing the panel in a 79.4 ° C (175 ° F) for 90 seconds warm, commercially available alkaline cleaning solution. After rinsing for 20 seconds in 25.6 ° C (78 ° F) warm tap water, the plate was placed in the loaung given above introduced and connected there as an anode. The plate underwent an anodizing treatment subjected to a voltage of 110 volts and a strength of 450 milliamps, the latter to 21Q milliamps within a treatment time of 1 minute sank. After this time, the power was turned off and the plate was then removed and dried in circulating air at 149 ° C (300 ° F) without purging. After scratching the organic coating, we the plate was subjected to the conditions prescribed by the "CASS" test for 17 hours exposed. For the plate became a "CASS" score of 8.6 determined and only very little corrosion could be found at the crater sites which proves that the alkyl phosphate coatings are self-sealing (self-bealing) are.

For comparison purposes, a cleaned aluminum plate was the same Size and composition in a solution containing 15 percent phosphoric acid by volume and contained 15 percent by volume sulfuric acid, at a temperature of about 25.6 ° C (780F) and a current density of 1.61 amps / dm2 (15 amps / sq.ft.) For 20 minutes.

Following the anodizing treatment, the plate was distilled in Rinsed water and then by immersing in boiling distilled water for 15 minutes Water sealed. The oxide coating on the plate was then scraped with scratches provided, and then the plate was prescribed for 17 hours in the "CASS test Exposed to conditions. The plate was given a "CASS" rating of 7.0. There was an extremely large number of pitted pits around the scratches and corrosion products recognizable. A comparison based on the percentage, weighed, damaged area part @ shows that the organic coating by 3.3 times was better, as the conventionally anodized surface (0.15 vs. 0.5).

The plate treated with the acid lauryl and stearyl p @ osphat w @ es thus a significant superiority.

A similar test was carried out with a plate made from the alloy @r. 6061, with a third of the plate after cleaning a total of 5 minutes long after the teaching of the present invention, as indicated in Example 5, was treated, another third of the plate remained untreated and the last Third cleaned, anodized for a total of 40 minutes, and sealed. By A scratch was made across the entire panel, and after that the plate was subjected to the conditions prescribed in the "AS" test for 17 hours exposed (val, see Figure 2). As can be seen from this, the first third showed of the plate which had been treated according to the teaching of the invention, a noticeable one Superiority on. As can also be seen, the scratch was without any influence the resistance to corrosion of that part of the plate which, according to the teaching of the invention had been treated.

Example 6 This example illustrates that alternating current Can be used successfully to electrolytically form an alkyl phosphate conversion coating to apply in a one-step operation.

2 polished and steam-degreased plates made of aluminum alloy No. 6062 of the format 50.8 x 152.4 mm were cleaned in such a way that the plates In a commercial cleaning solution (a alkaline cleaning solution with a retarding effect, the basic alkali salts, surface-active Containing substances and emulsifiers) dived. After the plates for 30 seconds in 25.6 ° C (78 ° F) warm @ water had been rinsed, they were in the solution of the acidic lauryl and stearyl phosphates described in Example 5 used as electrodes. 2 minutes lane: then became an AC voltage of 110 volts applied. During this treatment time, the current density decreased from the initial one 3 amps / dm2 (28 am / sq.ft.) To 1.51 amps./dm2 (14 amps / sq.ft.). The panels were then removed and dried in circulating air at 149 ° C (300 ° F) without purging, and then the plates were 17 studies in a row the prescribed for the "CASS" test Subject to conditions. A "CASS" rating of 8.5 was determined for each plate.

Bs seems important to point out that the corrosion resistance the coating applied by means of alternating current of the corrosion resistance of the same, but applied electrolytically in accordance with Example 5 by means of direct current coating was equivalent.

Example 7 The purpose of this example is to illustrate that the invention can be applied to pure aluminum as well as aut its alloys is.

Sample pieces of alloys No. 6063, 5557, 3003, 6061, 5005, 7075, 2025 and 1100 and made of pure aluminum cleaned and in an ethanolic-aqueous dispersion of acidic lauryl and stearyl phospha @ electrolytically treated according to the one-step operation described in Example 5. After drying in 149 ° C (300 ° F) circulating air, the patterns 17 Hours in a row at the "CASS" test prescribed conditions exposed.

As from the "CASS" rating numbers given in Table 4 below can be seen, exhibited the alkyl phosphate coatings on all of the alloys examined good corrosion resistance.

Table 4 Aluminum sample "CASS" rating number Alloy size after a 17-hour number. in five test pure aluminum 12.7 x 76.2 8.2 6063 50.8 x 152.4 7 7.6 5557 50.8 2, 4 8.5 3003 101.6 x 152.4 8.6 6061 101.6 x 152.4 8.2 5005 101.6 x 152.4 8.5 7075 101.6 x 152.4 7.5 2025 101.6 x 152.4 7.0 1100 101.6 t 152.4 8, 2 Example 8 An oxirane, namely the 1,2-epoxyoctadecane of the formula was prepared from 1-octadecene according to the procedure described by Swern, Billen and Sca @ nlan in Journal American Chemical Society, Volume 68 (1946) page 1504.

After its manufacture, the oxirane was in a molten state on a polished plate made of aluminum alloy No. 6063 in the format fo, 8 x 152.4 - Applied, with one half of the plate being a continuous layer of active, amorphous alumina hydrates.

The active, hydrated layer was electrod @@@ sch, as in Example 1 has been generated.

As already indicated in Table 1, the "CASS" rating number was good after 3 hours 9.2 in the treated half of the plate has been determined, which proves that a strong chemical bond had been achieved. The cleaned one, but on the other hand The untreated half of the plate had a low rating of 3.0.

In contrast, the application of 1-octadecene to a similarly treated aluminum panel to the low "CASS" rating of 3.0 after they were exposed to the conditions prescribed for the "CASS" test for 3 hours was.

These results illustrate that ethylene derivatives conforming to the general heterocyclic ring formula in which X can be O, NH or S, produce firmly adhering organic films or coatings on aluminum substrates which have been treated according to the teaching of the present invention.

Example 9 An example of a phosphinic acid derivative was diphenylphosphinic acid of the formula (C6H5) 2P (O) OH tested in an analogous manner by applying this acid on an active substrate of aluminum, which according to the information in Example 1 electrolytically had been generated, The Acid was made using a solution applied, which corresponded to the solution type described in example @ with the modification, that the phosphinic acid derivative is used in place of the acidic stearyl phosphate became. As indicated in Table 1, the use of this acid resulted in one chemically bonded film. which had the good "CASS" rating of 7.

Example 10 Stearic anhydride was applied to a hydrated aluminum surface applied in such a way that it is melted and then spread with a cotton cloth, as it is described in the test @A. It got the good "CASS" rating of 7.5 achieved.

Example 11 This example illustrates that the amorphous hydrate form des Aluminumoxy @ s differ in terms of their reactivity with selected organic functional groups behave chemically selectively. Groups that usually don't react with an aliphatic alcohol, neither react with the amorphous one Form of hydrated alumina.

Laurylaldehyde is an example of an organic alkyl compound having at least 8 carbon atoms, and it is characterized by a functional group, which usually does not react with an aliphatic alcohol. When trying apply an adherent conversion coating using lauryl aldehyde, was a polished plate made of alloy No. 6063 with a size of 50.8 x 152.4 mm cleaned and according to the in Example 1 described way 15 seconds long anodized in a sulfuric acid-phosphoric acid solution to produce an active, amorphous, generate hydrated oxide surface. The plate was then in a 25.6 ° C (78 ° F) warm, 25 percent by volume ethanol-water solution that is per liter Containing 5 ml of lauryl aldehyde, immersed. After this treatment, the plate was covered with Rinsed with distilled water and air dried at 23.9 ° C (75 ° F) and then 3 hours exposed to the conditions prescribed by the "CASS" test. It the low "CASS" score of 3.5 was achieved.

In a corresponding manner, as shown in the table below 5 see below, low "CASS" rating numbers in tests with other organic Compounds containing functional groups, which @ usually do not react with an aliphatic alcohol, namely with trilauryl phosphate (4.0), Lauryl alcohol (4.5), lauryl amide (3.0), 2-undecanone (3.5), lauronitrile (3.5), 1-octadecene (3.0) and laurylamine (3.5).

Other organic groups included in Table 5 and which have proven to be ineffective in the tests are 1-octadecene and a strongly polar, quaternary ammonium salt, the tridodecyl-methyl-ammonium chloride. The application of the 1-octadecene is explained in Example 8. The quaternary ammonium salt was applied in the molten state to the amorphous, hydrated aluminum surface upset.

Table 5 "CASS" -Weer- Organic Corrosion Compound number resistance lauryl aldehyde 3.5 low trilauryl phosphate 4.0 low lauryl alcohol 4.5 low laurylamide 3.0 low 2-undecanone 3.5 low lauronitrile 3.5 low laurylamine 5.5 low 1-Octadeden 3.0 low Tridodecyl-methyl-ammonium chloride +) 3.0 low +) This compound was applied to the pretreated aluminum surface in the in test 4A of Example 4 described manner applied.

When comparing Examples 1 to 10 (which work according to illustrate the teaching of the invention) with Example 11 (which is not under the It can be clearly seen that the superior results of the Invention can be achieved when the organic @ compounds have functional groups that react with the active, amorphous aluminum oxide hydrate.

In an attempt to characterize the application of the invention he @ elderly coating or film became a section of an aluminum plate which according to the ben of Example 1 with one using acid lauryl phosphate produced film was coated, examined under an electron microscope, and it became a Microphotography made in 200,000 times magnification. The investigation (see FIG. 1) showed that the film thickness (10) was of the order of magnitude was about 240 Angstrom units (so the film was about 8 molecules thick). It is indicative that the photomicrograph shows an underlayer structure of a non-porous Oxide barrier layer (11) of about 1500 Angstrom units thickness can be seen. Trot @ the fact that the thickness of the organic film is only 240 Angstrom units, However, the good "CASS" rating of about 8.5 was determined, which proves that the film is dense, non-porous and essentially impenetrable to the surrounding media is. The film is very adhesive and firmly bonded to the barrier layer as it is through the simple experiment is carried out in which part of the coated flatten is completely is bent around a rod about 25.4 mm in diameter, @he plate the at "CASS" test is set to the prescribed conditions. The not bent part It achieved a "CASS" rating of 8.5, whereas the curved part still did still had a good rating of at least 7. I am reminded that one conventionally anodized and sealed plate, which was made prior to the execution of the "CASS" test was bent, on the bent part a rating number of only 5 reached. A well-known white anodized aluminum substrate shows in one for comparison, a picture produced in 200,000 times magnification is a porous one Oxide structure.

As mentioned above, the active hydrate consumes the aluminum surface does not consist entirely of aluminum hydrate in order to achieve the advantageous To achieve results of the present invention. Depending on the generation of the active hydrate of alumina acids or salts used other ions can be present in the layer, such as chromate and / or Phosphate ions, provided that enough sites occupied by the active amorphous hydrate remain, which are sufficient to create the desired bond with the applied organic film enter into. To explain what has just been said, the following example is given: As the person familiar with the chemical oxidation processes is familiar with, contain conversion coatings that are applied to aluminum substrates using Chromate-phosphate solutions have been applied, usually chromium and phosphorus ions as well as a considerable amount of aluminum ions. Such coatings are for it known that they are compact and amorphous and that they have hydrated oxide coatings resemble and are not comparable to the conventional crystalline structure that is usually achieved, for example, in metal phosphating processes. These Coatings which contain the amorphous hydrate of aluminum oxide react with the organic compounds of the type described herein with respect to the invention.

To illustrate what was said in the previous paragraph, 8 plates of 50.8 x 152.4 mm format made of aluminum alloy No. 3003 with a amorphous chromate-phosphate coating, after which one half of each 4 plates 4 of those listed in Table 1 organic compounds applied which could be shown to interact with the amorphous hydrate of alumina react. In an analogous way, one half of the remaining X plates * of those organic compounds listed in Table 1 upset, which contain functional groups that are not the subject of the present invention belong. The selected organic compounds are compiled in Table 6. To make the samples to which the above procedures were applied, an acidic chromate phosphating solution available on the market has been used. Those obtained in the commercial solutions. Coatings are non-crystalline Part of @ @ubstratmetalles. The organic compound was applied by Soaking the lower half of each plate in a solution for 5 minutes, the 25 percent by volume of ethanol, 75 percent by volume of distilled water and per liter 3 g of the remaining organic compound or 5 ml of the liquid organic compound contained. The organically treated panels were then washed with cold water (25.6 ° C) it is rinsed and dried in circulating air at 25.6 ° C (78 ° F). Since isocyanates with React water, the liquid @ n-octadecyl isocyanate was applied by means of a cotton cloth applied and the excess iso- @ yanate then through 30 Immerse the plate in distilled water for minutes, occasionally Stir away.

After applying the organic compounds, the panels were Exposed for 3 hours to the conditions prescribed by the "CASS" test, and thereafter, the effect of the resulting coatings on the electrical conductivity with the help of a Z-scope impedance measuring device (Z-scope impedance measuring unit) bes @ immt. The chromate phosphating solution that is used to produce the samples was combined, provides a coating that is electrically conductive. thats why any substantial increase in the electrical resistivity in the with to the organic coated surface of the plate an indication that a chemical bond has occurred.

The results of the experimental investigations are shown in the table 6 compiled. As expected, there was a noticeable increase in impedance up to 1150% for organic compounds that contain functional groups, which are known to react with aliphatic alcohols such as the Phosphite, isocyanate, phosphate and monocarboxylic acid compounds. On the other hand had the treatment of the chromate phosphating coating with sol @@ en organic compounds, which contain functional groups that were not expected to react (Nitrile, ketone, aldehyde and amine compounds) to Polge that only a small amount or there was no increase in the specific electrical resistance at all.

Compare the impedance value of the eight connections in Table 6, It can thus be clearly seen that the improved results of the present invention then be achieved if an active, amorphous, hydrated aluminum oxide surface is made.

Table 6 ++) Abgebrach- Impedant in Kilooh @ te organi- functional Organically unincreased connec- tions treated or treated Group Area Area in% dilauryl phosphite phosphite 10.0 0.80 + 1 150 n-octadecyl isocyanate Isocyanate @.5 0.70 + 975 acid lauryl phosphate phosphate 1.75 0.63 + 180 stearic acid Monocarboxylic acid 1.40 0.72 + 94 lauronitrile nitrile 0.80 0.60 + 33 2-undecanone ketone 0.75 0.72 + 0.42 lauryl aldehyde 0.64 0.75 - 14.6 lauryl amine amine 0.48 0.56 - 21.5 +) A chromate-phosphate conversion coating was applied to a plate from the Aluminum alloy No. 3003 of the format 50.8 x 152.4 mm was applied and then was one half of the area treated with the organic compound.

++) Impedance (in kilo @ hm) to @ volts alternating current, measured for a Area of 0.1 cm2 with a Z-Oscillograph (Z-scope) from the Twin City Testing Company, Tonawanda, New York.

The present invention is openly also technically useful, to provide aluminum with a firmly adhering base layer on which subsequently thicker layers can be developed. For example, the base layer as an intermediate layer in the production of aluminum tape laminated with plastic or sheet metal or in the production of aluminum, which with aluminum to form a layer fabric is connected, serve, or it can be a plastic film that the desired having functional group, directly to the amorphous hydrate via a reaction product from the hydrate and the functional group.

Polyester films, vinyl chloride and the like can be made using pressure and heat or bonded directly by adhesives. It is known that on aluminum self-laminated vinyl chloride films - provided there is good adhesive strength achieved - have excellent toughness and wear resistance. These Laminates not only offer all the advantages of a pre-tempered material, but they can be based on their excellent properties according to almost any common @ Method can be processed further. For example, these laminates can easily bent, crimped, embossed, drilled, varformed, perforated, punched and sheared be careful not to damage the laminated cover.

A method of making a tightly bonded polyester cover is described in the following example.

Example 12 A buff polished aluminum plate (Format 50.8 x 152.4 mm; thickness 1.59 mm) from an aluminum alloy No. 3003 Pre-cleaned as in Example 1. and one half of the plate was then.

in a 26.74C (80 ° F) solution containing 15 volume percent sulfuric acid and contained 15 volume percent phosphoric acid for 15 seconds with direct current from approximately 11 to 12 volts at a current density of 1.61 amps / dm2 (15 amps sq.ft.) anodized, then in 23.9 ° C (75 ° F) tap water for 30 seconds and then Rinsed in 25.6 ° C (78 ° F) distilled water for 15 seconds. Through this Treatment became an adherent, essentially non-porous layer of one active, amorphous aluminum oxide hydrates are generated on the surface.

A polyester film sold under the name "@ylar" 44.5 x 127 mm (1 3/4 "x 5") and 0.051 mm (0.002 inch) thick was placed on the entire surface of the plate and using one made of Folytetrafluoroäthylen ("Teflon") manufactured spatula pressed onto its support while the plate was placed on a plate at about 249 ° C (480 ° F) for about 90 seconds. The plate was then removed from the pad and allowed to cool. The Flatte showed a shiny aluminum color. The coating was checked for its adhesive strength @Inserting a knife checked. The polyester coating initially looked solid to adhere.

The coated panel was then left open for 17 hours "CASS" test carried out and then washed in distilled Waszr. The adhesive strength was again determined after the "CASS" test by inserting a knife and the following was found: (a) The one with the non-anodized The polyester film bonded to the half of the plate showed poor adhesion, whereas (b) the polyester film with the one containing the active amoi'phe aluminum oxide hydrate Plate half was connected, showed good hardness thanks to the chemical Bond between the functional group of the polyester compound and the amorphous one Hydrate.

Another embodiment methods provide a laminated Product that is made of aluminum-on-aluminum and that is made up of a plurality of aluminum substrates, one active, hydrated, amorphous Layer of aluminum oxide to one with each of the substrates. Whole united and an organic base film adhering to each of the amorphous oxide layers a reaction product of the oxide layer is bound with an organic compound, which contains at least 8 carbon atoms and one functional, with an aliphatic Alcohol reactive group, the active, amorphous Oxydeohicht in chemically is characterized in that it is associated with the functional group how an alcohol can react, and each of the aluminum substrates to the other by the bonding contact at the interface where the organic reaction took place has, is bound. The base film can be a polymerized layer attached to the plastic films can be bound.

If one summarizes what has been said before, the result is that the present one Invention relates to a mode of operation according to which a homogeneous organic film over a reaction product is chemically bonded to the aluminum surfaces. This Film, the properties of which depend on the organic compound used, can act as a protective film, e.g. as a plastic film, which prevents corrosion is able to withstand, or it can be used as a base film for subsequent processing to serve. In this way, the base film can be used as an intermediate layer when building laminates Made of plastics and aluminum substrates can be used, or it can be used as a base for applying paints, enamels, epoxy resins and the like. For example Due to the nature of the original bond, combined overlays with or can be used can be produced without pigments to achieve a noticeably improved corrosion resistance noticeably improved electrical properties (e.g. dielectric Properties) and to improve the abrasion resistance and the like. Of the The base film should preferably be one that is polymerizable. So can the film can be built up e.g. from unsaturated hydrocarbons, e.g. from compounds, which have the unsaturation in the alkyl group.

The advantage of the chemically bonded film as an Srr coating is there that the diffusion of oxygen and / or moisture into the substrate metal can be largely prevented. Therefore the thickness of the coating does not need to be to be as substantial as is generally required of other coatings is to achieve the desired results.

Even if the present invention is preferably in question on the basis of it has been explained in the following forms, it goes without saying, that the skilled person are familiar with modifications and variations that he make can without departing from the principle and scope of the invention. Such modifications too and modifications are included within the scope of the present invention as set forth in FIGS the following claims are expressed.

Claims (26)

Claims 1. Method for modifying aluminum surfaces by means of a tightly bound film of an organic compound containing at least 8 carbon atoms contains and has a functional group that is reactive with an alcohol, characterized in that one. an active, hydrated, amorphous layer of Aluminum oxide, which unites with the aforementioned aluminum surface to form a whole and which is chemically like an alcohol with the functional group of the chosen ones organic compound is able to react, b11-det, then the surface of the said active, hydrated, amorphous layer with said organic Bringing compound into contact for the purpose of producing an organic film that adheres to the said aluminum surface by means of a reaction product of said functional Group with the mentioned active, hydrated, amorphous aluminum oxide layer is formerly bonded at the bonding interface of this film. 2. The method according to claim 1, characterized in that the aluminum surface is brought into contact with an organic compound selected from the group of carboxylic acids or their acid anhydrides, phosphinic acids, acidic organic phosphates and acidic phosphites, including those in which at least one oxygen atom replaced by a sulfur atom, the organic isocyanates, diisocyanates, isothiocyanates and diisothiocyanates, ketenes, ethylene derivatives with a three-membered heterocyclic ring of the general formula in which X can be 0, NH or 5, the ester of the formula type RCOOR ?, the organic sulfonates, organic sulfates, sulfinic acids and organic carbonates is selected. 3. The method according to claim 2, characterized in that said organic compounds in a. Some include acids of the formula types RC02H and R (CO2H) 2J, acid anhydrides of the formula type (RCO) 20, phosphinic acids of the formula type R2P (O) OH, acid phosphates of the formula types (RO) 2P (O) OH and ROP (O) (OH ) 2, acid phosphites of the formula types (RO) 2POH and ROP (OH) 2, thiophosphates of the formula types (RO) 2PS (OH) and ROP (S) (OH) 2, thiophosphites of the formula types (RS) 2POH and RSP (OH) 2, isocyanates and diisocyanates of the formula types RNCO and R (NCO) 2, isothiocyanates of the formula type RNCS and diisothiocyanates of the formula type R (NCS) 2, ketenes of the formula type RCH = C = O, ethylene oxide derivatives of the formula type Ethylenimine derivatives of the formula type Formula-type ethylene sulfide derivatives Esters of the formula type RCOOR ', organic sulfonates of the formula type organic sulfates of the formula type Sulfinic acids of the formula type RSOOH and organic carbonates, where R can in each case denote an alkyl, aralkyl, aryl or alkaryl group. 4. The method according to Ahspruch 3, characterized in that the reaction product originates from an organic compound of the specified types of formulas, in which the Re5t R is an unsaturated alkyl group. 5. The method according to claim 4, characterized in that the functional Group of said unsaturated alkyl compound consists of a carboxyl group. 6. The method according to claim 3, characterized in that the reaction product such a product consists of one of the specified formula types in which the group R is polymerizable. 7. The method according to claims 1 to 3, characterized in that that the hydrated, amorphous layer of alumina creates in such a way is that the aluminum surface with an aqueous solution of a mineral acid brings in contact until gas evolution on the surface enters, and then rinses the surface. 8. The method according to claims 1 to 3, characterized in that that the hydrated, amorphous layer of alumina creates in such a way becomes that the aluminum surface for such a long time to the anode in a aqueous solution of a mineral acid, which is sufficient to make the active, amorphous, to form hydrated layer of alumina. 9. The method according to claims 1 to 8, characterized in that that the surface of the said object is cleaned and then the object, connected as an anode, the action of an aqueous bath »which the said Organic compound contains, exposes, so an active, hydrated, amorphous Layer of alumina in situ on the surface of said object to form which layer then chemically interacts with the functional like an alcohol Group of the organic compound mentioned reacts and produces a film that bound to the said aluminum object by means of a reaction product test is. 10. The method according to claims 1 to 9, characterized in that that the reaction product is derived from an acidic alkyl phosphate. 11, the method according to claim 10, characterized in that the acidic Alkyl phosphate from at least one representative of the two compounds acidic stearyl phosphate uuad consists of acid lauryl phosphate. 12. The method according to claims 1 to 3, characterized in that that the organic compound on the surface of the active, hydrated, amorphous Layer as - laminate is applied in the form of a plastic film, which is a mit of said amorphous layer has reactive functional group. 13. The method according to claim 12, characterized in that the plastic film laminate consists of polyvinylidene chloride. 14. The method according to claims 1 to 3, characterized in that that each of a plurality of aluminum surfaces with one tightly bonded an organic film coating is provided and that furthermore the aluminum surfaces mentioned are stacked so that their respective coatings are in contact with each other whereupon the stack is bound via the organic coatings for the purpose of formation an aluminum-on-aluminum laminate follows. 15. The method according to claim 14, characterized in that the organic Film made of polyvinylidene chloride. 16. Aluminum surfaces with an organic chemical bonded to them Film characterized in that it is a reaction product at its binding interface a functional group of an organic compound with an active, hydrated, amorphous layer of Alumii'iumoxydes, which with t the aluminum surface to is united as a whole, wherein said organic compound Contains at least 8 carbon atoms and the mentioned functional group with one Aliphatic Al-alcohol is reactive, and said active, hydrated layer of aluminum oxide like an alcohol with the mentioned functional group for the purpose of forming said reaction product which is essentially insoluble in water is to respond ver-inag. 17. Aluminum surface according to claim 16, characterized in that said organic compound bound thereto from the group of carboxylic acids and their acid anhydrides, phosphinic acids, acidic organic phosphates and acidic phosphites including those in which at least 1 oxygen atom is replaced by a sulfur atom can be, the organic isocyanates, diisocyanates, Isothiocya @ ate and diisothiocyanates, the ketenes, ethylene derivatives with a three-membered heterocyclic ring of the general formula in which X can be 0, NH or S, the ester of the formula type RCOOR ', selected from organic sulfonates, organic sulfates, sulfinic acids and organic carbonates, and said active, hydrated barrier layer of aluminum oxide with the mentioned functional group such as an alcohol refuses to react chemically. 18. Aluminum surface according to claim 17, characterized in that said organic compounds include acids of the formula types RCO2H and R (CO2H) 2, acid anhydrides of the formula type (RCO) 2O, phosphinic acids of the formula type R2P (O) OH, acidic phosphates of the formula types (RO) 2P (O) OH and ROP (O) (OH) 2, acid phosphites of the formula types (RO) 2POH and ROP (OH) 2, thiophosphates of the formula types (RO) 2P (S) OH and ROP (S) ( OH) 2, thiophosphites of the formula types (RS) 2POH and RSP (OH) 2, isocyanates and diisocyanates of the formula types RNCO or R (NCO) 2, isothiocyanates of the formula type RNCS and diisothiocyanates of the formula type R (NCS) 2, ketenes of Formula type RCH = C = O, ethylene oxide derivatives of the formula type Ethylenimine derivatives of the formula type Formula-type ethylene sulfide derivatives Esters of the formula type RCOOR ', organic sulfonates of the formula type organic sulfates of the formula type Sulphinic acids of the formula type RSOOH and organic carbonates of the formula type where R can in any case denote an alkyl, aralkyl, aryl or alkaryl group. 19. Aluminum surface according to claim 18, characterized in that that the reaction product of an organic compound of the formulas given originates in which the radical R consists of an unsaturated alkyl group. 20. Aluminum surface according to claim 19, characterized in that that the functional group of said unsaturated alkyl compound consists of a Carboal group best. 21. Aluminum surface according to claim 20, characterized in that that the reaction product from such a product has one of the formulas given consists in which the group R is polymerizable. 22. Product of manufacture according to claims 16 to 18, characterized characterized in that the reaction product is derived from an acidic alkyl phosphate. 23. Production product according to claim 22, characterized in that that the acidic alkyl phosphate consists of at least one representative of the two compounds acidic stearylphosphate and acidic laurylphosphate. 24. Plastic-laminated aluminum sheet, the cross-section of which is a Has aluminum substrate, characterized by an active, hydrated, amorphous Layer of aluminum oxide which unites with the named substrate to form a whole is, and a plastic laminate, which consists of an organic compound that chemically arn said amorphous oxide layer via a reaction product of said Oxide layer is bound to the organic compound mentioned, which latter Contains at least 8 carbon atoms and one reactive with an aliphatic alcohol having functional group, said amorphous Oiydschicht like an alcohol able to react chemically with the functional group mentioned. 25. Plastic-laminated sheet metal according to claim 24J, characterized in that that the plastic consists of polyvinylidene chloride. 26. Laminate product constructed from aluminum-on-aluminum, the cross-section of which has several aluminum substrates, characterized by a active, hydrated, amorphous layer of aluminum oxide associated with each of the above Substrate is combined into a whole, and a plastic laminate, which consists of a 1 organic connection exists which is attached to each of the aforementioned amorphous oxide layers via a reaction product of said oxide layer with a functional group said organic compound containing at least 8 carbon atoms is chemically bonded, the functional group being zenit an aliphatic alcohol is reactive and said active, amorphous oxide layer how an alcohol can react with said functional group, and each of the mentioned aluminum substrates to the other through the bonding contact their plastic sides are bound. L e r s e i t e