MXPA98002196A - Composition and process for treatment of aluminum surface and its alloys - Google Patents

Abstract

The present invention relates to an aqueous liquid surface treatment composition having a pH value not higher than 6.5 and containing phosphoric acid ions, condensed phosphoric acid ions, an oxidizing agent, a water soluble polymer consisting of, except for the terminal groups, of polymer units expressed by the formula (I), in a weight ratio of 0.1 to 30: 0.1 to 10: 0.1 to 10: 0.1 to 20 respectively, when placed in contact with a surface of aluminum metal , quickly forms on the surface a conversion coating that has good resistance to corrosion and adhesion for organic coatings subsequently applied such as paint and is less easily damaged by mechanical stresses than conversion coatings of the prior art.

Description

COMPOSITION AND PROCESS FOR TREATMENT OF ALUMINUM SURFACE AND ITS ALLOYS Technical Field The present invention relates to a novel composition and method for the surface treatment of aluminum and its alloys, such as aluminum-manganese alloys, aluminum-magnesium alloys and aluminum-silicon alloys, which contain at least 45o by weight of aluminum, all of which are jointly referred to hereinafter as "aluminum metals", in which the surface of an aluminum metal is provided with better resistance to corrosion and adhesion to paint or film. synthetic resin before this surface is painted or laminated to a synthetic resin film. One field in which the present invention can be applied in a particularly effective manner is the surface treatment of aluminum coils.

BACKGROUND OF THE INVENTION Chromate treatments are currently being used for the most part in the industrial treatment of surfaces of aluminum coils. Common examples of chromate treatments include chromic acid chromate conversion treatments and chromate phosphoric acid conversion treatments. Solutions for chromic acid chromate conversion treatment were put into practical use around 1950 and are still widely used for fin members and the like in heat exchangers. This chemical conversion treatment solution consists primarily of chromic acid (Cr03) and hydrofluoric acid (HF), with an added promoter, and forms a film containing some hexavalent chromium. Solutions for the phosphoric acid chromate conversion treatment are based on the invention of US Patent 2,438,877 of 1945. This chemical conversion treatment solution contains chromic acid (Cr?), Phosphoric acid (H3P04) and hydrofluoric acid (HF) . The film that forms consists mainly of hydrated chromium phosphate (CrP04-4H20). Since the film does not contain hexavalent chromium, it is now widely used for coating treatments inferior to the painting of beverage can bodies, particularly cans and lids of stretched and die-cut aluminum. However, with the interest in environmental protection has arisen the need for surface treatment solutions that do not contain chromium. In recent years, paint or lamination followed by surface treatment has been followed by an increasingly widening range of forming processes, with the need for increasingly stringent processing levels, but films made from inorganic systems such as chromate suffer from of these problems, for example, the film breaks when it bends excessively preventing proper operation and the like. Thus, there is a strong demand to develop a technique for forming a flexible film with better corrosion resistance and / or adhesion in manufacturing products that are formed after carrying out the conversion coating process. Treatment solutions or methods proposed to provide the surface of aluminum metals with corrosion resistance and adhesion to paint using a water-soluble resin have been proposed in Japanese Patent Applications open to the public 61-91369, 1- 172406, 1-177379, 1-177380, 2-609, 2-608 and others. In these conventional treatment methods, the metal surface is treated with a solution "containing a derivative of a polyhydric phenol compound. However, the problems in these conventional methods are that it is difficult to form a sufficiently stable film in a short period of time on the surface of aluminum metallic materials and it is not possible to obtain an adequate corrosion resistance.

Description of the invention Problems that are solved by the invention The present invention is proposed to remedy the aforementioned disadvantages of conventional technology and, more specifically, it is proposed to offer a novel composition and a method for the surface treatment of aluminum metals, "which allows the surface of an aluminum metal to be provided, in a short period of time, with better resistance to corrosion and adhesion of the paint or laminated film without the use of chromium and, which also allows a film with better functionality to be formed.

SUMMARY OF THE INVENTION It has been found that a liquid, aqueous surface treatment composition containing phosphoric acid ions, condensed phosphoric acid ions, an oxidant and a water soluble polymer, with a specific structure, and having a pH within of a specific range forms a film with better resistance to corrosion and adhesion to paint or laminated film, as well as better functionality, when a surface of an aluminum metal is brought into contact with this composition for surface treatment.

More particularly, a composition according to the invention for the surface treatment of an aluminum metal consists, preferably consists essentially of, or more preferably consists of water and: (A) an ion component of orthophosphoric acid; (B) an ion component of condensed phosphoric acid (s); (C) an oxidizing agent component; and (D) a component of polymer molecules and / or water-soluble oligomers which comprise, except terminal groups, the following general formula (I): wherein each of X1 and X2 independent of each other and independently of a unit of the polymer, this unit being defined as represented by a modification of the formula (I) above in which the brackets and the subscript n are omitted, for another polymer unit represent a hydrogen atom, an alkyl group from Ci to C, or a hydroxyalkyl group from Ci to C5; each of Y1 and Y2 independent of each other and independently of each polymer unit represents a hydrogen atom or a "Z" portion which forms one of the following general formulas (II) and (III): -CH 2-N (Hl) in which each of R :, R2, R5, R'1 and R5 in each of the general formulas (II) and (III) independently represent an alkyl group of Ci to Ci? or a hydroxyalkyl group from Ci to Ciu; a "Z" portion may be identical or may be different from any other "Z" portion in the polymer molecule, as long as each "Z" is in accordance with one of the general formulas (II) and (III); and n represents a positive integer, which may be the same or different from the value of n for any other polymer molecule; furthermore, in component (D) as a whole: the average value for the number of substituted "Z" portions in each phenyl ring of the polymer molecule 1, can be referred to hereafter as "the average value for the substitution of the Z-portion. ", is from 0.2 to 1.0; the average value of n, which can be referred to hereafter as "the average degree of polymerization", is from 2 to 50 and, because it is an average, it is not necessary to be an integer; and, optionally, one or both of the following components: (E) an aluminum sequestering agent component "that is not part of any of the previously mentioned components; and (F) an antifoaming agent component that is not part of any of the above-mentioned components, and in the composition as a whole, the phosphoric acid ions (A), the condensed phosphoric acid ions (B), the oxidizing agent (C) and the above-mentioned water-soluble polymer (D) are present in a weight ratio (A): (B): (C): (D) from 0.1 to 30: 0.1 to 10: 0.1 to 10: 0.1 20. A composition according to the invention can be immediately suitable for use as such in the treatment of aluminum metals, in which case it is known as a 1 For example, if a polymer with an average degree of polymerization of 10, containing 20 benzene rings, has only 10 of these 20 benzene rings substituted with a group Z, the average Z group substitution rate of the polymer is: i ( lx 10) + (0 x 10 ') / 20' 0.5 working composition, or it may be adequate to dilute with additional water to form a working composition, in which case it is known as a concentrated composition. Some compositions are suitable for both purposes. A process for the surface treatment of an aluminum metal, in accordance with the present invention, is characterized in that an aqueous surface treatment solution containing the aforementioned surface treatment composition pertains to the present invention and that it has a pH value not greater than 6.5, it contacts the surface of an aluminum metal, preferably for a total of 1 to 60 seconds, and the surface thus contacted, preferably is then rinsed with water, and then dried and preferably it warms up DETAILED DESCRIPTION OF THE INVENTION, INCLUDING PREFERRED EMBODIMENTS Orthophosphoric acid, which has the chemical formula H3P04 and is commonly referred to herein simply as "phosphoric acid" unless the context requires differentiation from other phosphoric acids, and any salt soluble in water or acid salt of the orthophosphoric acid which does not adversely affect the objectives of the invention, can be used as a source of component (A) of a composition according to the invention, as defined above, and any of these salts should be understood, for the purpose of the preferences set forth below, as a contribution to their complete stoichiometric equivalent as orthophosphate ions (ie, Po 3) for the concentration thereof in any composition according to the invention , regardless of the actual degree of ionization that may prevail in the composition. The ion content of the phosphoric acid is in the range from 0.1 to 30 parts by weight, and preferably from 0.5 to 5 parts by weight, by 0.1 to 20 parts by weight of the water soluble polymer (D) in the aforementioned ratio . An ion content of phosphoric acid of less than 0.1 parts by weight in the ratio of the aforementioned mixture usually gives rise to inadequate reactivity between the surface treatment solution and the surface of the metal substrate to be coated, as well as in a inadequately formed film. More than 30 parts by weight in this ratio does not damage the formation of a favorable conversion coating but is uneconomic due to the high cost of the treatment solution and the absence of any outstanding benefit compared to the compositions containing a little less of this component.

In the same way, one or two or more types selected from pyrophosphoric acid, tripolyphosphoric acid and tetrapolyphosphoric acid and the salts of all these acids, can be used to provide the condensed phosphoric acid ions in a water-based composition of this invention, but the invention is not limited to the use of these materials. Any water-soluble source of any phosphate anion containing at least two phosphorus atoms may be used, and shall be understood for the purposes of the following preferences as providing its full stoichiometric equivalent as condensed phosphate anions for the composition used in accordance with the invention, independent of the actual degree of ionization that exists in the composition. For example, pyrophosphoric acid (HP_0 /), sodium pyrophosphate (Na4P20,) and similar compounds can be used to provide pyrophosphate ions. In a composition for the surface treatment according to the present invention, the content of the component (B) of condensed phosphoric acid ions is in the range from 0.1 to 10 parts by weight, and preferably from 0.5 to 3.0 parts by weight , by 0.1 to 20 parts by weight of the water-soluble polymer (D). An ion content of condensed phosphoric acid of less than 0.1 parts by weight in the aforementioned ratio will usually give rise to a surface treatment solution with weak etching action, preventing adequate formation of a film. A content greater than 10 parts by weight will usually give rise to a surface treatment solution with mordant action that is too strong, which inhibits the film forming reaction. In a surface treatment composition according to the present invention, the oxidizing agent preferably consists, more preferably essentially consists of, or still more preferably contains one or more substances which are selected from the group consisting of hydrogen peroxide, chlorates and nitrates; the most preferred being hydrogen peroxide. The content of the component oxidizing agent (C) in the aforementioned ratio for the surface treatment composition according to the present invention is in the range from 0.1 to 10 parts by weight, and preferably from 2 to 5 parts by weight, per 0.1 to 20 parts by weight of the water soluble polymer component (D). A content of oxidizing agent of less than 0.1 parts by weight will usually give rise to a treatment solution with weak mordant action, avoiding the adequate formation of a film. More than 10 parts by weight will usually give rise to a treatment solution with mordant action that is too strong, which inhibits the forming reaction of the film.

The water-soluble polymer used in the present invention is a water-soluble polymer (a term suggested herein to include oligomers) having an average degree of polymerization of 2 to 50, or preferably 2 to 20, and which contains, preferably consists essentially of, more preferably consists of (except for terminal groups) polymer units as described above in connection with the general formula (I). When alkyl or hydroxyalkyl groups represented by X1 and X2 in the general formula (I) have six or more carbon atoms, the resulting polymer becomes bulky, usually causing steric hindrance and preventing obtaining a compact film with good resistance to corrosion. When the average value of the Z substitutions is less than 0.2, the resulting polymer usually has poor water solubility, and the stability of the resulting surface treatment composition is usually inadequate. When the average value for the substitution of the Z portion is more than 1.0, and thus contains a substantial fraction of benzene rings substituted by two or more groups Z, the polymer usually has such a high water solubility, a composition containing it as component (D) has great difficulty in the formation of a satisfactorily protective surface film. The alkyl or hydroxyalkyl groups expressed by R1, R2, R3, R4 and R5 in the general formulas (II) and (III) have from 1 to 10 carbon atoms. A number of carbon atoms of 11 or more will usually result in a polymer molecule that is too bulky, giving rise to a film with poor density and insufficient corrosion resistance. In a surface treatment composition according to the present invention, the content of the water-soluble polymer component (D), in terms of the aforementioned ratios to the other components, is 0.1 to 20 parts by weight, and preferably 0.5. to 5 parts by weight per 0.1 to 30 parts by weight of the phosphoric acid ions (A). When this ratio is less than 0.1 parts by weight, it is difficult to form a film on the surface of the aluminum metals with the surface treatment composition, while more than 20 parts by weight in this ratio is uneconomic due to the high cost of the composition. resulting surface treatment and the absence of any substantial improvement over the results achieved with a composition according to the invention containing 20 or fewer parts in this ratio.

Although not narrowly limited, the pH of a working composition for surface treatment according to the present invention, preferably is not more than 6.5 and even more preferably is between 2.0 and 6.5. When the pH of the composition for the surface treatment is higher than 6.5, the polymer of the formula (I) in the resulting surface treatment composition will tend to precipitate, damaging the stability of the treatment composition and its lifetime of use. When the pH is less than 2.0, the biting action of the surface treatment composition on the surface of the metal material is very strong, making the formation of a surface film difficult. The pH of the composition of surface treatment can be adjusted using an acid such as phosphoric acid, nitric acid and hydrochloric acid or an alkali such as sodium hydroxide, sodium carbonate and ammonium hydroxide. Hydrofluoric acid can be used to adjust the pH when elimination in sewage is not a problem. In a surface treatment method according to the present invention, the aforementioned surface treatment solution preferably has a pH of 2.0 to 6.5 and contains from 1 to 30 grams per liter (herein abbreviated as " g / 1") of phosphoric acid ions, from 0.1 to 10 g / 1 of condensed phosphoric acid ions, from 0.1 to 10 g / 1 of oxidizing agent and from 0.1 to 20 g / 1 of component (D) water-soluble polymer as described above. When the concentration of the phosphoric acid ions in a surface treatment composition according to the invention is less than 0.1 g / 1, a surface film is usually inadequately formed, while more than 30 g / 1 is little economic due to its high costs. When the concentration of the condensed phosphoric acid ions is less than 0.1 g / 1 the biting action of the resulting surface treatment composition is usually too weak, and a surface film is improperly formed, while, more than 10 g / 1 will give rise to a surface treatment composition with mordant properties that are so strong that it prevents the film forming reaction. When the concentration of the oxidizing agent is less than 0.1 g / 1, the etching action of the resulting surface treatment composition is weak, usually preventing the formation of a suitable film, while more than 10 g / 1 will result a surface treatment composition with too high mordant action, which prevents the film forming reaction. When the concentration of the water soluble polymer component (D) is less than 0.1 g / 1, the resulting surface treatment composition usually has an inadequate film forming capacity, while more than 20 g / 1 is economically disadvantageous because the costs are higher. When the aluminum ions which have eluted from the aluminum metal are mixed with the surface treatment composition, the water-soluble polymer (D) and the metal ions sometimes form a complex and produce precipitation. In these cases, an aluminum sequestering agent must be added to the surface treatment composition. Examples of useful aluminum sequestering agents include, but are not limited to, ethylenediaminetetraacetic acid, 1,2-cyclohexane diaminetetraacetic acid, triethanolamine, gluconic acid, heptoglyconic acid, oxalic acid, tartaric acid, malic acid, and organophosphonic acids. When the use of hydrofluoric acid presents no problems for the treatment of wastewater, it can be used as a sequestering agent. In a method of the present invention, a working composition for the surface treatment as described above, is contacted, preferably for a total of 1 to 60 seconds and independently preferably at a temperature within a range of 30 seconds. at 65 ° C, with a surface of an aluminum metal. The film that is formed on the surface of the metal material is then preferably rinsed with water and subsequently preferably heated and dried. The contact between the aluminiferous metal and a working composition can be established by any convenient method, among which the immersion of the substrate in a bath of the working composition and the spraying of the working composition on the metal are the most common. A contact time of less than 1 second will usually result in inadequate formation of a corrosion resistant film, while a contact time of more than 60 seconds does not produce major benefits and thus will result in lower operating efficiency . When a spray treatment is used, the surface treatment composition sometimes forms foam and in this way causes problems in the film that is formed. Although the presence or absence of foam and the extent of this foaming largely depends on the equipment and conditions of the spray, an antifoam agent must be added to the surface treatment composition when foaming can not be adequately prevented by the modification to the equipment and the spray conditions. The type of antifoam agent, the amount of use and others are not closely limited, but the adhesion between the resulting film and the paint or the laminated film should not be compromised. The film formed on the surface of the aluminum metals in a process according to the invention is considered a film of an organic-inorganic composition consisting mainly of phosphates and polymer (resin) (D) soluble in water. The metallic substrate is etched by the phosphoric acid ions and the condensed phosphoric acid, at which time the pH becomes high in some areas at the interface, resulting in the precipitation of the phosphates on the surface. The amino groups (including the Z groups) of the water-soluble polymer (D) have chelating action, and are considered to form a type of coordination compound with the regenerated surface of the metal substrate produced by the etching. Although the organic-inorganic compound film is formed basically as a result of the aforementioned actions, the additional presence of the condensed phosphoric acid ions in the surface treatment composition appears to allow some of the coordination compound (s) The water-metal soluble polymer is formed more easily, thereby allowing the formation of a stable organic-inorganic complex film to form on the metal surface within a wide pH range.

After a coating film has been formed in a process according to the invention, the film can be and preferably heated to allow the polymer of the component (D) of the working composition according to the invention that was used , and that was incorporated in the coating film formed on the surface, is subjected to another polymerization on the surface. At least one minute at 200 ° C (in the normal ambient natural atmosphere) is sufficient for the heating conditions. Next, a sequence of steps for the preferred extended treatment process is mentioned, using a surface treatment composition according to the present invention. (1) Clean / degrease the surface (any type of acid, alkaline or solvent); (2) Rinse with water; (3) Treat the surface (by the method of the present invention); (4) Rinse with water; (5) Rinse with deionized water; (6) Heat and dry; (7) Paint or film lamination. Before implementing the method of the present invention, the surface of the metal material is preferably cleaned to degrease it from oil such as rolling oil or the like which remains on the surface of the aluminum metal to be treated. No specific restrictions are imposed on the type of degreasing agent or degreasing method used in this step. The degreased material is preferably rinsed with water. The rinsing is proposed to eliminate the degreasing composition of the surface; therefore, any method for rinsing can be used, as long as the degreasing composition is removed from the surface. Then the surface treatment of the method according to the present invention is implemented. The surface of the aluminum metal to be treated preferably is further rinsed with water. This rinse is proposed to remove the surface treatment composition, so that any rinse method can be used, provided that the unreacted surface treatment composition is removed from the surface. The treatment and drying are proposed to dry the rinse water, without tight restrictions imposed on the method, the drying temperature, the drying time or the like although drying with hot air or the like is usually useful for industrial purposes. The surface of the aluminiferous metal that has been treated on the surface is then painted or laminated with film. The coating that is formed by a method according to the present invention has good adhesion to paint or laminated films. Since the coating formed by means of the present invention is also flexible, it also has excellent performance after processing such as bending or stretching. The aluminiferous metals that are used in the method according to the present invention include forms such as leaves, rods, wire ropes and the like. No restriction is imposed on the dimensions and configuration of the metal, although the method according to the invention is especially effective when used on coils of aluminum metal. The present invention is described in more detail below in relation to the specific working and comparative examples.

Examples and Comparative Examples Evaluation Methods (1) Resistance to Corrosion The corrosion resistance of aluminum metals (resistance to browning caused by boiling water) was evaluated by the following test: The treated aluminum objects were bent in the U-shape around a round bar with a diameter of one millimeter (henceforth usually abbreviated as mm); these were immersed for 30 minutes in boiling tap water; and the degree of discoloration (darkening) in the folded portions was evaluated visually. No obscuration was classified as "0", the partial dimming was classified as "?" and the total dimming was classified as "X". (2) Adhesion of the paint The adhesion of the paint was tested in the following way: paint based on polyvinyl chloride for cans was painted with a thickness between 5 and 10 microns (henceforth commonly abbreviated as "μ" ) on the treated aluminum surface, followed by one minute of baking at 260 ° C; the samples were cut into rectangles of 5 x 150 mm; the painted surfaces were thermally bonded through a polyamide film to form test pieces, the bent surfaces were separated by the peeling test method or 180 degree peel; and resistance to desquamation was evaluated at that time. The greater the resistance to peeling, the better adhesion of the paint. In general, a peel strength of 4.0 kilograms-force (hereinafter commonly abbreviated as "kgf") or more than 5 mm in width is considered excellent for practical purposes. (3) Removal of waste water The waste of the surface treatment composition used was diluted 20 times with water, and the concentration of hexavalent chromium in this formed composition was measured. For environmental protection purposes, chromium should not be detected.

Example 1 A sheet of aluminum-magnesium alloy (alloy according to the Japanese Industrial Standard, hereinafter commonly abbreviated as "JIS", A5182) was degreased by spraying with an aqueous solution of the 2nd of an alkaline degreaser ( trade name: FINECLEANER® 4377K, from Nihon Parkerizing) for 5 seconds at 60 ° C, and then it was cleaned by rinsing with water. The sheet was then sprayed for 3 seconds at 60 ° C with the "Surface Treatment Composition 1 having the following ingredients, water being the difference, this was then rinsed with tap water, then sprayed and washed for 10 seconds with deionized water with a specific resistivity of at least 3,000,000 ohm-centimeters, and then dried for 2 minutes in a drying oven with hot air at 80 ° C. Composition of Surface Treatment 1 Phosphoric acid (ed. , H3P04) 75%: 10.0 g / l (P0"3: 7.2g / l) Sodium pyrophosphate (ie, Na4P_0 / - 10H.O): 3.0g / l (P2? -, 1: 1.2g / l) Hydrogen peroxide in water at 31%: 10.0g / l (H_0_: 3.1g / 1) Polymer (1) - part of solids: 2.0g / l PH 4.0 (adjusted with sodium hydroxide) The polymer (1) soluble in water was according to the general formula (I) when: the average value of n = 5; each of X1 and X2 represent a hydrogen atom; each of Y1 and Y2 represent a portion -CH2N (CH3) 2 or hydrogen atoms; and the substitution number of the average Z portion = 0.50 EXAMPLE 2 Aluminum alloy materials were degreased and rinsed in the same manner as in Example 1, and these were then treated by immersion for 10 seconds at 40 ° C using the Surface Treatment Composition 2 having the ingredients shown. then with the difference being water.

That treatment was followed by rinsing and drying under the same conditions as in Example 1. Composition of Surface Treatment 2 Phosphoric acid (ed, H3P04) 75%: 10.0 g / l (P04-3: 7.2 g / 1) Pyrophosphate of sodium (ie, Na4P.O / - IOH ^ O): 3.0g / l (P2O7"4: 1.2g / l) Hydrogen peroxide in water at 31%: 15.0g / l (H, 0,: 4.6g / l) 1) Polymer (2) - part of solids: 0.4 g / 1 PH 3.0 (adjusted with sodium carbonate) The water soluble polymer (2) was according to the general formula (I) when The average value of n = 5, each of X1 and X2 = a portion -C2H5, each of Y1 and Y2 = a portion - CH ^ NÍCH ^ CH ^ OH) or hydrogen atom, and the average value for the substitution of the Z = portion 0.25.

EXAMPLE 3 Aluminum alloy sheets were degreased and rinsed in the same manner as in Example 1, then treated by spray for 1 second at 65 ° C using the Surface Treatment Composition 3 containing the ingredients shown below, with the difference of water, then they were rinsed and dried under the same conditions as in Example 1. Composition of Surface Treatment 3 Phosphoric acid (ed, H3P0) 75%: 20.0 g / 1 (P04 ~ 3: 14.4 g / 1) Sodium pyrophosphate (ie, Na4P¿O / -10H2O): 6.0g / l (P2O7"*: 2.4g / l) Hydrogen peroxide in water at 31%: 15.0 g / l (H_0,: 4.6g / l) 1) Polymer (3) - part of solids: 8.0 g / 1 pH 4.0 (adjusted with sodium hydroxide) The water soluble polymer (3) was according to the general formula (I) when: the average value of n = fifteen; each of X1 and X2 = a -C2H5 portion; each of Y1 and Y2 = a portion -CH2N (CH1CHOH) or hydrogen atom; and the average value for the substitution of the Z = 1.0 portion.

EXAMPLE 4 Aluminum alloy sheets were degreased and rinsed in the same manner as in Example 1, then spray-treated for 30 seconds at 40 ° C using the Surface Treatment Composition 4 with an ingredient content as shown. Then, with the difference of water, they were then rinsed and dried under the same conditions as in Example 1. Composition of Surface Treatment 4 Phosphoric acid (ed, H3P04) 75%: 20.0 g / l (P0 ~ 3: 14.4 g / 1) Sodium tripolyphosphate (ie, 43% sodium chlorate in water: 10.0 g / 1 (NaC10¿: 4.3 g / 1) Polymer (4) - part of solids: 1.0g / l pH 4.0 (adjusted with ammonia aqueous) The water soluble polymer (4) was according to the general formula (I) when: the average value of n = 15, each of XJ and X2 = represents a hydrogen atom, each of Y1 and Y2 = represents a portion -CH2N (CH2OH) 2 or hydrogen atom, and the average value for the substitution ution of the Z portion = 0.50.

EXAMPLE 5 Aluminum alloy sheets were degreased and rinsed in the same manner as in Example 1, then treated by spraying for 5 seconds at 50 ° C using the Surface Treatment Composition 5 containing the ingredients shown below , with the water difference, then they were rinsed and dried under the same conditions as in Example 1. Composition of Surface Treatment 5 Phosphoric acid (ed, H3P04) 75%: 20.0 g / 1 (P04 ~ 3 14.4g / l ) Pyrophosphoric acid (ie, H4P207) 1.0 g / l (P207"4 0.98g / l) 31% hydrogen peroxide in water: 5.0 g / 1 (H_0_: 1.6 g / 1) Polymer (5) - part of solids : 1.0 g / 1 pH 3.5 (adjusted with aqueous ammonia) The water soluble polymer (5) was according to the general formula (I) when: the average value of n = 20, each of X1 and X2 = one atom of hydrogen, each of Y1 and Y = a portion -CH2N (CH2CH2CH2OH) 2 or hydrogen atom, and the average value for the substitution of the Z = 0.75 portion. Comparative Example 1 Aluminum alloy sheets were degreased and rinsed in a manner as in Example 1, and then treated by spraying for 5 seconds at 50 ° C using the Surface Treatment Composition Cl with the ingredients set forth below , the difference being water. This treatment was followed by rinsing and drying under the same conditions as in Example 1. Composition of Surface Treatment Cl-without ions of condensed phosphoric acid or oxidizing agent Phosphoric acid (ed, H3P04) 75%: 20.0 g / l (P04"3: 14.4g / l) Polymer (6) - part of solids: 1.0 g / 1 pH 3.5 (adjusted with aqueous ammonia) The water-soluble polymer (6) was according to the general formula (I) when: average value of n = 10, each of X1 and X2 = one hydrogen atom, each of Y1 and Y2 = one portion -CH2N (CH2CH2CH20H) 2 or hydrogen atom, and the average value for the substitution of the Z-portion = 0.75 Comparative Example 2 Aluminum alloy sheets were degreased and rinsed in the same manner as in Example 1, then treated by spray for 2 seconds at 50 ° C using a 5% aqueous solution of a conversion composition. chemistry of the phosphoric acid type chromate available in the commercial io (trade name: ALCHROME® K702, from Nihon Parkerizing). The treatment was followed by rinsing and drying under the same conditions as in Example 1.

Comparative Example 3 Aluminum alloy sheets were degreased and rinsed in the same manner as in Example 1, then treated by sprinkling for 10 seconds at 50 ° C using a 6% aqueous solution of a chemical conversion composition of the phosphate type. Zirconium available commercially (trade name: AEROSIL® 404, from Nihon Parkerizing). The treatment was followed by rinsing and drying under the same conditions as in Example 1. Table 1 shows the results obtained in the evaluations of Examples 1 to 5 and Comparative Examples 1 to 3 above. Table 1 As seen from the results in Table 1, Examples 1 to 5, which use a method according to the present invention, have better resistance to corrosion, adhesion and removal of waste water. In Comparative Example 1, the surface treatment composition that did not contain ions of condensed phosphoric acid or oxidizing agent, gave rise to a film with inadequate corrosion resistance and adhesion to paint. In Comparative Example 2 and 3, conventional surface treatment compositions were used, resulting in films with little corrosion resistance. In Comparative Example 2, the residual water contained hexavalent chromium, while in Comparative Example 3 the adhesion to the paint was poor. BENEFITS OF THE INVENTION From the aforementioned description it is evident that the surface treatment composition and the method according to the present invention allow a chemical conversion film with better resistance to corrosion and adhesion to the paint to be formed on surfaces of aluminum metals before they are painted. The surface treatment composition and the method according to the present invention are of the chromium-free and fluorine-free type, and have exceptional merit in eliminating the problem of wastewater disposal.

Claims (1)

1. CLAIMS . A liquid composition of material, suitable for use as such, after dilution with water, or both, as such and after dilution with water, for the surface treatment of aluminum metals, said composition with a water content and: ( A) an ion component of orthophosphoric acid; (B) an ion component of condensed phosphoric acid (s); (C) an oxidizing agent component; and (D) a component of polymer molecules and / or water-soluble oligomers which comprise, except terminal groups, the following general formula (I): wherein each of X1 and X2 independent of each other and independently of a unit of the polymer, this unit being defined as represented by a modification of the formula (I) above in which the brackets and the subscript n are omitted, for another polymer unit represent a hydrogen atom, an alkyl group of Ci to C ", or a hydroxyalkyl group of Ci to C5; each of Y1 and Y2 independent of each other and independently of each polymer unit represents a hydrogen atom or a "Z" portion which forms one of the following general formulas (II) and (III): -CH. - .NN (IH) wherein each of R1, R2, R3, R "1 and R5 in each of the general formulas (II) and (III) independently represent an alkyl group of Ci to Ci? or a hydroxyalkyl group of Ci to Ci? A "Z" portion may be identical or may be different from any other "Z" portion in the polymer molecule, as long as each "Z" conforms to one of the general formulas (II) and (III); represents a positive integer, which may be equal to or different from the value of n for any other polymer molecule, in addition, in component (D) as a whole: the average value for the number of "Z" portions substituted in each phenyl ring of the polymer molecule, which can be referred to hereafter as "the average value for the substitution of the Z-portion", is from 0.2 to 1.0, the average value of n, which can be referred to hereafter as "the average degree of polymerization" "is from 2 to 50 and, because it is an average, it is not necessary to be an integer; this composition as a whole, the phosphoric acid ions (A), the condensed phosphoric acid ions (B) the oxidizing agent (C), and the water-soluble polymer (D) mentioned above are present in a weight ratio (A): (B): (C): (D) from 0.1 to 30: 0.1 a 10: 0.1 to 10: 0.1 to 20. The composition as defined in claim 1, wherein the oxidizing agent component includes at least one material that is selected from the group consisting of hydrogen peroxide, chlorates and nitrites. The composition as defined in claim 2, wherein the phosphoric acid ions (A), the condensed phosphoric acid ions (B), the oxidizing agent (C) and the water soluble polymer (D) are present in a weight ratio (A): (B): (C): (D) from 0.5 to 5: 0.5 to 3.0: 2 to 5: 0.5 to 5 composition as defined in claim 1, wherein the phosphoric acid ions (A) the condensed phosphoric acid ions (B), the oxidizing agent (C) and the water soluble polymer (D) are present in a ratio of weight (A): (B): (C): (D) from 0.5 to 5: 0.5 to 3.0: 2 to 5: 0.5 to 5. 5. A method for the treatment of an aluminiferous metal surface comprising a step of contacting the aluminiferous metal surface with an aqueous liquid surface treatment composition containing a composition as defined in any of claims 1 to 4 and having a pH value not greater than 6.5. The method according to claim 5, wherein the contact between the aluminiferous metal surface and the aqueous liquid surface treatment composition is maintained for a time from 1 to 60 seconds at a temperature from 35 to 65 ° C, and the surface which has thus been put in contact is rinsed with water after the contact is discontinued and subsequently rinsed. The method according to claim 6, wherein the dry formed surface has been or will be subsequently heated to a temperature of at least 200 ° C for a time of at least one minute in the ambient atmosphere. The method according to claim 6 or 7, wherein the surface treatment composition has a pH of from 2 to 6.5 and contains: from 1 to 30 g / 1 of the component (A); from 0.1 to 10 g / 1 of component (B); from 0.1 to 10 g / 1 of the component (C); and from 0.1 to 20 g / 1 of component (D). The method according to claim 5, wherein the surface treatment composition has a pH of 2.0 to 6.5 and contains: from 1 to 30 g / 1 of component (A); from 0.1 to 10 g / 1 of component (B); from 0.1 to 10 g / 1 of the component (C); and from 0.1 to 20 g / 1 of component (D).