CN1092246C - Polymeric compound composition and process for surface-treating an aluminum-containing metal material - Google Patents

Abstract

A surface of aluminiferous metal is brought into contact at 30 DEG C. to 65 DEG C. for 5 to 60 seconds with a surface treatment bath with a pH of 2.0 to 6.5 that contains phosphate ion, condensed phosphate ion, and a water soluble polymer in the following weight proportions: 1-30: 0.1-10: 0.2-20. This is followed by a water rinse and drying by heating. The water soluble polymer has a chemical structure conforming with formula (I): (I) in which (i) each of X1 and X2 represents a hydrogen atom, a C1 to C5 alkyl group, or a C1 to C5 hydroxyalkyl group; (ii) each of Y1 and Y2 represents a hydrogen atom or a moiety ''Z'' that conforms to formula (II) or (III): (II) and R5 represents a C1 to C10 alkyl group or a C1 to C10 hydroxyalkyl group; (iii) the average value for the number of Z moieties substituted on each phenyl ring in the polymer molecule is from 0.2 to 1.0; (iv) n is an integer with a value from 2 to 50; and (v) each polymer molecule contains at least one Z moiety.

Description

Polymer compositions and methods for surface treating aluminum-containing metal materials

The present invention relates to a polymer surface treatment composition for aluminum-containing metal materials and a method for surface treatment of aluminum-containing metal materials with the composition.

More particularly, the present invention relates to polymeric surface treatment compositions suitable for use in the surface treatment of aluminum-containing metal materials prior to coating the surface with paint, thereby imparting to the surface excellent corrosion protection properties and paint adhesion properties, The invention also relates to a method of surface treating aluminum-containing metal materials with the polymer composition.

The polymer compositions and methods of the present invention can be effectively used on aluminum-containing metal cans manufactured by drawing and pressing prior to painting and printing. This surface treatment significantly improves the corrosion resistance and paint adhesion of the stretched and ironed cans, D and I cans, and imparts a high slip that is necessary for smooth conveyance of the D and I cans by means of a conveyor. This property of being able to be transported smoothly by means of a conveyor will hereinafter be referred to as "on-conveyor portability" of the cans.

Surface treatment solutions for aluminum-containing metal materials, ie, aluminum materials and aluminum alloy materials, are generally classified into chromate-type surface treatment solutions and chromate-free type surface treatment solutions.

Typical chromate-type surface treatment solutions are chromic acid-chromate chemical conversion coating solutions and phosphoric acid-chromate chemical conversion coating solutions.

Chromic acid-chromate chemical conversion coating solutions were put into use around 1950 and are still widely used on various aluminum-containing metal materials, such as fin components of heat exchangers. The chromic acid-chromate chemical conversion coating solution contains chromic acid (CrO ₃ ) and hydrofluoric acid (HF) as the main components and an accelerator added to the main components, and the solution can form on the surface of metal materials. Coatings containing a certain amount of hexavalent chromium.

The phosphoric acid-chromate chemical conversion coating solution is based on the invention described in US Patent No. 2438877 (1945). The chemical conversion paint solution contains chromic acid (CrO ₃ ), phosphoric acid (H ₃ PO ₄ ) and hydrofluoric acid (HF) as main components, and a coating formed from the chemical conversion paint solution on a metal material contains as The main compound is hydrated chromium phosphate (CrPO ₄ ·4H ₂ O). Phosphoric acid-chromate chemical conversion coating solutions are still widely used to form base coats for paint coatings on beverage can bodies and lids because the resulting chemical conversion coatings do not contain hexavalent chromium.

A typical non-chromate type chemical conversion coating solution is an acidic (pH about 1.0-4.0) aqueous coating solution containing at least one selected from the group consisting of zirconium, titanium, zirconium compounds and titanium compounds, phosphates and fluorides. When the surface of an aluminum-containing metal material is chemically converted using the above-mentioned typical non-chromate solution, a chemical conversion coating containing chromium oxide and/or titanium oxide as a main component is formed on the surface. The advantage of the above-mentioned non-chromate type chemical conversion coating solution is that the formed coating does not contain harmful hexavalent chromium. These two properties of the chemical conversion treatment liquid are inferior.

Both chromated and non-chromated conversion coating solutions contain fluorine-containing compounds. However, due to environmental pollution problems, it has recently been required to provide surface treatment liquids that do not contain fluorine compounds.

Japanese Unexamined Patent Publication Nos. 61-91369, 1-172406, 1-177,379, 1-177,380, 2 Regarding surface treatment solutions and surface treatment methods for imparting improved corrosion resistance and good coating adhesion to aluminum-containing metal materials -608 and 2-609 describe the application of water-soluble resins. In these conventional surface treatment solutions and methods, the surface of a metal material is treated with an aqueous solution of a polyvalent phenolic compound. The disadvantage of such conventional surface treatment solutions and methods is that it is difficult to form a very stable resin coating on the surface of metal materials, and the resulting resin-coated metal materials do not have satisfactory anti-corrosion properties. Even in Japanese Unexamined Patent Publication No. 4-66671 which introduces the improvement of the above-mentioned conventional method by using a polyvalent phenolic compound, the adhesiveness of the obtained resin coating is still sometimes unsatisfactory.

Currently, for the surface treatment of D and I aluminum cans manufactured from aluminum alloy sheet forming by stretching and ironing methods, non-chromium materials selected from phosphoric acid-chromate chemical conversion coating solutions and zirconium-containing chemical conversion coating solutions are generally used. Salt type surface treatment solution.

The exterior bottom surfaces of D and I aluminum cans are usually pasteurized prior to coating. Thus, if the corrosion resistance of the outer bottom surface is poor, this part of the D and I aluminum cans will be oxidized and discolored and blackened. This phenomenon is called bottom-top coloring. In order to avoid this phenomenon, the coating itself formed on the aluminum can by the surface treatment method must show good anti-corrosion performance even before the coating is applied.

In addition, during the canning process, a plurality of cans are transferred by a conveyor. When there is significant friction between the outer surfaces of the cans, the outer surfaces of the cans do not slide smoothly, so the cans can turn sideways, preventing a smooth transfer. A smooth transfer is especially important when the cans are sent to the printing step. Therefore, in the canning industry, it is very necessary to reduce the static coefficient of friction between the outer surfaces of the cans without having any adverse effect on the adhesion of the coating or the ink on the outer surfaces of the cans.

As an attempt to improve the mobility of the outer surface of the can, Japanese Unexamined Patent Publication No. 64-85292 discloses a metal can containing a water-soluble organic substance selected from the group consisting of phosphoric acid esters, alcohols, monobasic and polybasic fatty acids, fatty acid derivatives, and mixtures of the above compounds surface treatment agent. This surface treatment chemical effectively improves the mobility of aluminum cans. However, such surface treatment chemicals do not improve the anti-corrosion properties and paint adhesion of surface-coated cans.

It is an object of the present invention to provide an aqueous composition and method for the surface treatment of aluminum-containing metal materials to form a resin having good corrosion protection properties and coating adhesion when applied to the surface of aluminum-containing metal materials coating.

Another object of the present invention is to provide an aqueous composition and method for the surface treatment of aluminum-containing metal materials in D and I can forms in order to form a method capable of imparting good corrosion resistance, strong paint adhesion and High flow resin coating.

The above objects can be achieved by means of the present invention's aqueous composition for the surface treatment of aluminum-containing metal materials, which composition contains: (a) phosphate ions, (b) condensed phosphate ions, (c) at least one of the general formula ( I) shown water-soluble polymer: In the formula, X ¹ and X ² each independently represent a group selected from a hydrogen atom, a C _1-5 alkyl group and a C _1-5 hydroxyalkyl group; Y ¹ and Y ² represent a group independently of each other A group selected from a hydrogen atom and a substituent Z represented by formulas (II) and (III): In the formula, R ¹ , R ² , R ³ , R ⁴ and R ⁵ each independently represent a group selected from C _1-10 alkyl and C _1-10 hydroxyalkyl, linked to a single The substituents Z on the benzene ring can be the same or different from each other, the average number of substituents Z connected to a single benzene ring in the polymer unit is 0.2-1.0, n represents the average degree of polymerization of 2-50, and the phosphate ion (a), the weight mixing ratio (a):(b):(c) of polycondensed phosphate ion (b) and water-soluble polymer (c) is 1-30:0.1-10:0.1-20.

In addition, the method of the present invention for surface treatment of aluminum-containing metal materials includes the following steps:

式中X¹和X²分别彼此独立地代表一种选自氢原子、C_1-5烷基和C_1-5羟基烷基的基团；Y¹和Y²分别彼此独立地代表一种选自氢原子和式(II)和(III)所示的取代基Z的基团：

式中R¹、R²、R³、R⁴和R⁵分别彼此独立地代表一种选自C_1-10烷基和C_1-10羟基烷基的基团，连结在聚合链节的单独苯环上的取代基Z可以彼此相同或不同，连结在聚合单元中单独苯环上的取代基Z的平均数为0.2-1.0，n代表数值为2-50的平均聚合度，磷酸盐离子(a)、缩聚磷酸盐离子(b)与水溶性聚合物(c)之间的混合重量比(a)∶(b)∶(c)为1-30∶0.1-10∶0.1-20；(A) bringing an aqueous surface treatment solution containing (a) phosphate ions, (b) condensed phosphate ions, and (c) at least one water-soluble polymer and having a pH of 6.5 or less, to the surface of an aluminum-containing metal material at 30 -65 DEG C are contacted for 5-60 seconds in total, and the water-soluble polymer (c) is shown in general formula (I):

In the formula, X ¹ and X ² independently represent a group selected from a hydrogen atom, a C _1-5 alkyl group and a C _1-5 hydroxyalkyl group; Y ¹ and Y ² represent a group independently selected from each other A group from a hydrogen atom and a substituent Z shown in formulas (II) and (III):

In the formula, R ¹ , R ² , R ³ , R ⁴ and R ⁵ each independently represent a group selected from a C _1-10 alkyl group and a C _1-10 hydroxyalkyl group, which are linked to individual polymer chain members. The substituent Z on the benzene ring can be identical or different from each other, and the average number of the substituent Z on the independent benzene ring in the polymerization unit is 0.2-1.0, and n represents the average polymerization degree that the value is 2-50, and the phosphate ion ( a), the mixing weight ratio between polycondensed phosphate ion (b) and water-soluble polymer (c) (a): (b): (c) is 1-30: 0.1-10: 0.1-20;

(B) cleaning the grease coating formed on the surface of the aluminum-containing metal material with water;

(C) Heating and drying the resin coating after cleaning.

The surface treatment solution preferably contains 1-30 g/L phosphate ion (a), 0.1-10 g/L condensed phosphate ion (b) and 0.1-20 g/L water-soluble polymer (c), the pH of which is 2.0-6.5 is better.

The aqueous polymer composition for the surface treatment of aluminum-containing metal materials according to the present invention is composed of (a) phosphate ions, (b) condensed phosphate ions and (c) at least one of the formulas (I) Acidic aqueous solution of the water-soluble polymer of the polymerized unit shown.

In the polymer composition of the present invention, phosphate ions can be derived from phosphoric acid (H ₃ PO ₄ ), alkali metal salts of phosphoric acid such as sodium phosphate and ammonium phosphate.

Condensed phosphate ions in the aqueous compositions of the present invention include pyrophosphate ions, tripolyphosphate ions and tetrapolyphosphate ions. The condensed phosphate ion can be obtained from pyrophosphoric acid (H ₄ P ₂ O ₇ ), alkali metal pyrophosphate, and alkali metal tripolyphosphate and tetrapolyphosphate.

In the polymer composition used for surface treatment of aluminum-containing metal materials in the present invention, the phosphate ion (a), the condensed phosphate ion (b) and the water-soluble polymer (c) having a polymer unit (I) The weight ratio between them is 1-30:0.1-10:0.2-20, preferably 1-5:0.5-30:0.5-5.

If the content of phosphate ion (a) corresponding to the polycondensed phosphate ion (b) of 0.5 to 3.0 parts by weight and the polymer (c) of 0.2 to 20 parts by weight is less than 1 part by weight, the surface treatment solution formed will be Does not react sufficiently with the surface of aluminum-containing metal materials to form a satisfactory amount of resin coating. In addition, if the content of phosphate ion (a) corresponding to 0.1 to 10 parts by weight of condensed phosphate ion (b) and 0.2 to 20 parts by weight of polymer (c) is greater than 30 parts by weight, the resulting aqueous composition will be Too expensive, although satisfactory resin coatings can be formed.

If the content of condensed phosphate ion (b) corresponding to 1-30 parts by weight of phosphate ion (a) and 0.1-20 parts by weight of water-soluble polymer (c) is less than 0.1 part by weight, the resulting surface treatment solution will show Insufficient etching effect to form a satisfactory resin coating on the surface of metallic materials. In addition, if the content of condensed phosphate ion (b) corresponding to the above ratio of phosphate ion (a) and water-soluble polymer (c) is greater than 10 parts by weight, the resulting surface treatment solution exhibits an excessively strong etching effect Formation of the resin coating is thereby suppressed.

If the content of water-soluble polymer (c) corresponding to 1-30 parts by weight of phosphate ion (a) and 0.1-20 parts by weight of condensed phosphate ion (b) is less than 0.1 part by weight, the surface treatment solution formed will be A satisfactory resin coating cannot be formed on the surface of the metal material. In addition, if the content of the water-soluble polymer (c) corresponding to the above ratio of phosphate ion (a) and condensed phosphate ion (b) is more than 20 parts by weight, the resulting surface treatment solution is too expensive, so that The surface preparation process is cost-prohibitive.

式中X¹和X²各自代表选自下列的一种基团：氢原子、C_1-5烷基例如甲基、乙基、正丙基、异丙基和正丁基以及C_1-5羟基烷基例如甲氧基和乙氧基；Y¹和Y²分别代表选自氢原子和式(II)与(III)所示取代基Z：

式中R¹、R²、R³、R⁴和R⁵分别代表选自下列的一种基团：C_1-10烷基例如甲基、乙基、丙基和丁基，以及C_1-10羟烷基例如甲氧基和乙氧基。The water-soluble polymer (c) suitable for the present invention contains multiple polymerized (repeated) units represented by formula (I), and its average degree of polymerization n=2-50.

In the formula, X ^and X ^each represent a group selected from the group consisting of hydrogen atom, C _1-5 alkyl such as methyl, ethyl, n-propyl, isopropyl and n-butyl and C _1-5 hydroxyl Alkyl groups such as methoxy and ethoxy; ^Y and ^Y represent respectively a substituent Z selected from a hydrogen atom and formulas (II) and (III):

In the formula, R ¹ , R ² , R ³ , R ⁴ and R ⁵ respectively represent a group selected from the following groups: C _1-10 alkyl such as methyl, ethyl, propyl and butyl, and C _{1- 10} Hydroxyalkyl groups such as methoxy and ethoxy.

In the water-soluble polymer (c) having polymeric chains represented by formula (I), the substituents Z represented by Y ¹ and Y ² are linked to a single benzene ring of the polymeric chain, and they may be the same or different. The water-soluble polymer (c) must have at least one substituent Z linked to at least one single benzene ring of at least one polymer chain member represented by formula (I). That is, the average number of substituents Z connected to a single benzene ring of the polymer chain member represented by formula (I) is 0.2-1.0. This is hereinafter referred to as "average substituent Z-number of substitutions" and is calculated as follows.

If the average degree of polymerization of the water-soluble polymer (c) is 10, the polymer (c) has 20 individual benzene rings. If among the 20 individual benzene rings, 10 single benzene rings each have a substituent Z, the average substituent Z-number of substitutions of the polymer is [(1×10)+(0×10)]/20= 0.5.

If the average substituent Z-substitution number is less than 0.2, the resulting polymer exhibits poor solubility in water, and thus the resulting aqueous surface treatment composition and solution exhibit low stability during storage and use. In addition, if the average substituent Z-number of substitution is greater than 1.0, that is, the polymer has at least one single benzene ring substituted with two or more substituent Z, the resulting polymer exhibits too high water solubility, making it difficult to obtain Resin coating.

The alkyl and hydroxyalkyl groups represented by ^X1 and ^X2 in formula (I) have 1 to 5 carbon atoms. If the number of carbon atoms in the alkyl group and hydroxyalkyl group exceeds 6, the molecule of the resulting polymer becomes too large and steric hindrance occurs. It is therefore difficult to form a resin coating having a satisfactory density and excellent corrosion resistance.

In the formulas (II) and (III) of substituents, the alkyl and hydroxyalkyl groups represented by R ¹ , R ² , R ³ , R ⁴ and R ⁵ have 1 to 10 carbon atoms. If the number of carbon atoms is 11 or more, the resulting polymer molecule is too large so that the resulting resin coating has a low density and its anticorrosion effect is not satisfactorily improved.

The average degree of polymerization of the polymer (c) is 2-50. If the average degree of polymerization is less than 2, the anticorrosion effect of the resulting resin coating is not satisfactorily improved. If the average degree of polymerization is greater than 50, the resulting aqueous surface treatment composition and solution have problems in stability during storage and use, and thus are difficult to use.

The pH value of the aqueous surface treating polymer composition of the present invention is not particularly limited. It is usually better to control it at a level of 6.5 or lower.

In the method of the present invention, the surface treatment aqueous solution is prepared from the polymer composition, preferably by diluting it with water, and adjusting the pH value of the aqueous solution to 6.5 or lower, preferably 2.0-6.5.

If the pH value is greater than 6.5, the resulting aqueous solution for surface treatment is unstable during storage and use, and the polymer (c) tends to precipitate out of the aqueous solution. If the pH value is less than 2.0, the resulting aqueous solution exhibits too strong an etching property on the surface of the aluminum-containing metal material, so it is difficult to form a resin surface coating.

The pH of the surface treatment aqueous solution can be adjusted by using an acid such as phosphoric acid, nitric acid or hydrochloric acid, or a base such as sodium hydroxide, sodium carbonate or ammonium hydroxide. If there is no environmental pollution problem, hydrofluoric acid can be used to control the pH value.

In the method of the present invention, the surface treatment aqueous solution preferably contains: 1-30 g/liter phosphate ion (a), 0.1-10 g/liter condensed phosphate ion (b) and 0.1-20 g/liter water-soluble polymer ( c), its pH value is 2.0-6.5.

If the concentration of phosphate ion (a) is less than 1 g/L, the resin coating cannot be formed sufficiently, and if the concentration is greater than 30 g/L, the obtained surface treatment aqueous solution will be too expensive, thereby increasing the cost of the surface treatment method.

In addition, if the concentration of the condensed phosphate ion (b) is less than 0.1 g/L, the obtained surface treatment aqueous solution has poor etching performance on the metal material surface, so that the resin coating layer cannot be formed sufficiently. If the concentration is higher than 10 g/L, the resulting aqueous solution for surface treatment has too strong etching properties, thereby hindering the reaction between the solution and the surface of the metal material to form a resin coating.

In addition, if the concentration of the water-soluble polymer (c) is less than 0.1 g/L, the resulting aqueous surface treatment solution cannot sufficiently form a resin coating. If the concentration is higher than 20 g/l, the resulting aqueous surface treatment solution will be too expensive, thereby increasing the cost of the surface treatment process.

In the surface treatment method of the present invention, the aluminum ions are eluted from the aluminum-containing metal material into the surface treatment aqueous solution, the water-soluble polymer (c) can react with the aluminum ions, and the resulting complex of aluminum and the polymer (c) It can be deposited from the surface treatment aqueous solution. In order to prevent deposition, it is better to add aluminum ion chelating agent to the surface treatment aqueous solution. The aluminum ion chelating agent preferably contains at least one selected from the group consisting of ethylenediaminetetraacetic acid, Cy-DTA, triethanolamine, gluconic acid, heptagluconic acid, oxalic acid, tartaric acid, malic acid and organic sulfonic acid. However, the chelating agent is not limited to the above compounds. In the wastewater treatment process, if there is no environmental pollution problem, hydrofluoric acid can be used as a chelating agent.

In the method of the present invention, the above-mentioned surface treatment aqueous solution is in contact with the surface of the aluminum-containing metal material at 30-65°C, preferably 40-50°C, for 5-60 seconds, preferably 10-20 seconds.

In one embodiment of the contacting step, the aluminum-containing metal material is immersed in the aqueous surface treatment solution at 30-65°C for 5-60 seconds.

In another embodiment of the contacting step, the aqueous surface treatment solution is sprayed on the surface of the aluminum-containing metal material at a temperature of 30-65° C. within a contact time of 5-60 seconds. In this embodiment, two or more spraying steps are preferably performed at intervals of 2-5 seconds, with all spraying intervals lasting 5-60 seconds.

In the spray coating operation, the surface treatment aqueous solution sometimes foams, and therefore, the resulting resin coating contains foam. Therefore, foam formation and foaming conditions vary with spraying equipment and conditions. If foaming cannot be prevented by controlling the spraying equipment and conditions, a defoamer must be added to the surface treatment aqueous solution. The type and amount of the antifoaming agent are not limited unless the addition of the antifoaming agent will reduce the adhesion of the formed resin coating.

The aqueous polymer composition used in the present invention for surface treatment of aluminum-containing metal materials is prepared by the following method.

An aqueous solution containing phosphate ion (a) and condensed phosphate ion (b) in the mixing weight ratio as described above is prepared by dissolving phosphoric acid or phosphate and condensed phosphoric acid or condensed phosphate in water and stirring the solution. If the pH of the solution does not reach 7 or below, acid is added to bring the pH down to the desired level of 7 or below, followed by adding the water-soluble polymer (c) to the solution containing the phosphate ion (a) and polycondensation phosphate ion (b) in an aqueous solution while stirring the solution and then adjusting the pH of the resulting aqueous solution to the desired level of 6.5 or less.

The following describes the resin coating formed on the surface of the aluminum-containing metal material.

The resin coating produced by the method of the present invention is an organic-inorganic composite layer, which contains phosphate derived from phosphate ion (a) and condensed phosphate ion (b) as the main component and is represented by formula (I) Resin material derived from water-soluble polymer (c) of polymerized units. During the mutual contact between the surface treatment aqueous solution and the surface of the aluminum-containing metal material, the surface of the metal material is etched by phosphate ions (a) and condensed phosphate ions (b). As etching occurs, the pH value at the interface between the solution and the surface of the metal material being etched increases locally so that phosphate is deposited on the surface of the metal material. In addition, the amino or ammonium substituent Z in the polymer (c) has metal chelating properties, so that the polymer (c) reacts with the etched and activated surface of the metal material to form a certain coordination polymer. Due to the generation of phosphate and coordination polymer, an organic-inorganic composite layer is formed on the surface of the metal material.

Condensed phosphate ions (b) contained in the surface treatment aqueous solution can effectively promote the formation of polymer-metal complexes and lead to organic- Inorganic composite layer. In addition, a heat-drying step applied to the water-cleaned resin coating further polymerizes the resulting coordination polymer.

In order to develop strong anti-corrosion properties, it is preferable to heat treat the resin coating at 170-250°C for 1-10 minutes, for example at 200°C for 1 minute, in order to increase the degree of polymerization of the polymer.

The aluminum-containing metallic material suitable for use in the process of the invention is preferably selected from aluminum materials and aluminum alloy materials such as aluminum-manganese alloys in the form of plates, rods, tubes and wires. Aluminum-magnesium alloys and aluminum-silicon alloys. The shape and size of these materials are not limited.

The aqueous polymer composition of the present invention may optionally contain a preservative or an antifungal agent. These additives are effective in preventing putrefaction or mildew of the aqueous polymer composition or the aqueous surface treatment solution at low temperatures during storage or use. For this purpose, hydrogen peroxide is preferably used.

The surface treatment method of the present invention using the above-mentioned surface treatment aqueous solution will be described below.

Before surface treatment, use acid or alkali cleaners or organic solvents to remove grease on the surface of aluminum-containing metal materials, and wash the surface after removing dirt with water.

The surface of the aluminum-containing metal material is then contacted with the surface treatment aqueous solution by dipping or spraying at 30-65° C. for 5-60 seconds.

The resin coating formed on the surface of the metal material is washed first with water, then with deionized water, and finally heated and dried.

In the contacting step, the surface treatment aqueous solution is used at a temperature of 30-65°C. If it is lower than 30° C., the surface treatment aqueous solution cannot sufficiently react with the surface of the metal material, so that a satisfactory resin coating cannot be obtained. In addition, when the contact temperature is higher than 65°C, even if a satisfactory resin coating itself can be obtained, there is still a disadvantage of high energy consumption.

The dipping time should be 5-60 seconds. Shorter than 5 seconds is insufficient to form a satisfactory resin coating with high corrosion resistance. In addition, longer than 60 seconds, does not improve the properties of the formed resin coating.

When the surface treatment aqueous solution is applied to the surface of the metal material by spraying, if the solution is continuously sprayed within a certain period of time, there will be no local increase in the pH value at the interface between the surface of the metal material and the solution, so that the resin coating will not be fully formed. Therefore, it is best to carry out the spraying operation intermittently. That is, the spraying operation is divided into two or more steps with an interval of 2-5 seconds, and the interval and spraying time are completed within 5-60 seconds in total. If it is shorter than 5 seconds, the reaction between the surface of the metal material and the solution is not enough to complete, and the resin coating with excellent anti-corrosion properties cannot be provided. In addition, if it is longer than 60 seconds, the properties of the formed resin coating will not be improved accordingly.

Example

The following examples further describe the invention. In each of the Examples and Comparative Examples, the composition of the surface treatment aqueous solution and the surface treatment method detailed below were employed, and the following tests were conducted.

test

(1) Anti-corrosion performance

Determination of corrosion resistance, that is, the ability to resist top and bottom stains in boiling water, immerse D and I aluminum cans in boiling water for 30 minutes, and evaluate the degree of top and bottom stains on the surface of the cans by visual observation.

Grade Top and Bottom Pollution

3 Not found

2 parts

1 completely

(2) Coating adhesion

The epoxy urea resin coating for cans was applied to a thickness of 5-7 μm on the surface of the cans and baked at 215° C. for 4 minutes. The coating can was cut into rectangular samples with a width of 5 mm and a length of 150 mm. The rectangles were bonded to each other with a polyamide resin film by means of a heat press-bonding step to obtain a test piece. The peel strength of the test piece was measured through a 180-degree peel test.

The higher the peel strength, the stronger the paint adhesion for the can.

Aluminum cans with a peel strength of 4.0 kgf/5 mm width or higher are generally available for practical use.

(3) Mobility

Can mobility was assessed by measuring the static coefficient of friction of the can peripheral surface. The lower the static coefficient of friction, the higher the mobility of the tank.

Cans with a static coefficient of friction of 1.0 or less are generally available for practical use.

Example 1

Cans produced from aluminum-manganese alloy plates (A3004) by drawing and pressing were sprayed on the surface of the cans with the help of an acid degreaser 8% (w/w) produced by Nibon Parkarizing K.K. ) aqueous solution for degreasing, followed by washing the tank with water and drying.

On the surface of the cleaned D and I aluminum alloy cans, the surface treatment aqueous solution (1) with the composition shown below and heated at 60° C. was sprayed three times, each time lasting 5 seconds with an interval of 5 seconds. The total contact time was 25 seconds. The resin coating formed on the surface of the can was then washed with water, spray-washed with deionized water having a resistivity of 3,00,000 ohm cm or higher for 10 seconds, and finally dried in a hot air drier at 180°C.

Surface treatment aqueous solution (1) 75% phosphoric acid (H ₃ PO ₄ ) 10 g/L (PO ₄ ion: 7.2 g/L) sodium pyrophosphate (N ₄ P ₂ O ₇ 10H ₂ O) 3.0 g/L (P ₂ O ₇ ion: 1.2 g/L) water-soluble polymer (1) (average degree of polymerization = 5) 2.0 g (solid)/L In formula (I), X ¹ and X ² are hydrogen, Z=-CH ₂ N(CH ₃ ) ₂ , average substituent Z substitution number = 0.25. Adjust pH = 4.0 with aqueous sodium hydroxide.

Example 2

The same D and I aluminum alloy cans were cleaned according to Example 1.

The cleaned can was then immersed in the surface treatment aqueous solution (2) having the following composition at 60° C. for 20 seconds.

The resin coating formed on the surface of the drying can was cleaned as in Example 1.

Surface treatment aqueous solution (2) 75% phosphoric acid (H ₃ PO ₄ ) 10.0 g/L (PO ₄ ion: 7.2 g/L) sodium pyrophosphate (Na ₂ P ₂ O ₇ 10H ₂ O) 3.0 g/L (P ₂ O ₇ ion: 1.2 g/l) Water-soluble polymer (1) (see Example 1) 0.4 g (solid)/l Adjust the pH to 3.0 with aqueous sodium carbonate.

Example 3

The same D and I aluminum alloy cans were cleaned according to Example 1.

The cleaned can was then dipped in the surface treatment aqueous solution (3) having the following composition at 35°C for 60 seconds.

The resin coating formed on the surface of the drying can was cleaned as in Example 1.

Surface treatment aqueous solution (3) 75% phosphoric acid (H ₃ PO ₄ ) 20.0 g/L (PO ₄ ion: 14.4 g/L) sodium pyrophosphate (N ₄ P ₂ O ₇ 10H ₂ O) 6.0 g/L (P ₂ O ₇ ion: 2.4 g/l) water soluble polymer (1) (see Example 1) 8.0 g (solid)/l

The pH was adjusted to 6.0 with aqueous sodium hydroxide.

Example 4

The same D and I aluminum alloy cans were cleaned according to Example 1.

The cleaned surface of the tank was sprayed with the surface treatment aqueous solution (4) having the following composition and heated to 65° C. three times, each time lasting 6 seconds, with an interval of 2 seconds. It took a total of 22 seconds. The resin coating formed on the surface of the drying can was cleaned as in Example 1.

Surface treatment aqueous solution (4) 75% phosphoric acid (H ₃ PO ₄ ) 1.5 g/L (PO ₄ ion: 1.1 g/L) sodium pyrophosphate (Na ₄ P ₂ O ₇ 10H ₂ O) 5.0 g/L (P ₂ O ₇ ion: 2.0 g/l) Water-soluble polymer (1) (see Example 1) 4.0 g (solid)/l Adjust the pH to 2.5 with aqueous nitric acid.

Example 5

The same D and I aluminum alloy cans were cleaned according to Example 1.

The cleaned can was then immersed in an aqueous surface treatment solution (5) having the following composition at 60° C. for 30 seconds.

The resin coating formed on the can surface was washed and dried according to Example 1.

Surface treatment aqueous solution (5) 75% phosphoric acid (H ₃ PO ₄ ) 30.0 g/L (PO ₄ ion: 21.6 g/L) sodium tripolyphosphate (Na ₅ P ₃ O ₁₀ ) 1.2 g/L (P ₃ O ₁₀ Ion: 0.8 g/l) water-soluble polymer (1) (see Example 1) 0.4 g (solid)/l

Adjust pH=3.5 with aqueous sodium hydroxide solution.

Example 6

The same D and I aluminum alloy cans were cleaned according to Example 1.

The surface treatment aqueous solution (6) with the following composition and heated to 60°C was sprayed on the cleaned tank surface twice, each time for 5 seconds, with an interval of 5 seconds, and the total contact time was 15 seconds. The resin coating formed on the surface of the can was washed and dried as in Example 1.

Surface treatment aqueous solution (6) 75% phosphoric acid (H ₃ PO ₄ ) 10.0 g/L (PO ₄ ion: 7.2 g/L) sodium pyrophosphate (Na ₄ P ₂ O ₇ 10H ₂ O) 3.0 g/L (P ₂ O ₇ ion: 1.2 g/L) water-soluble polymer (2) 2.0 g (solid)/L average polymerization degree=5, in formula (I), X ¹ and X ² =-C ₂ H ₅ , Z= -CH ₂ N(CH ₂ CH ₂ OH) ₂ , the average substituent Z substitution number = 1.0. The pH was adjusted to 5.0 with aqueous sodium hydroxide solution.

Example 7

The same D and I aluminum alloy cans were cleaned according to Example 1.

The cleaned can was immersed in the surface treatment aqueous solution (7) having the following composition at 60° C. for 30 seconds.

The resin coating formed on the can surface was washed and dried as in Example 1.

Surface treatment aqueous solution (7) 75% phosphoric acid (H ₃ PO ₄ ) 10.0 g/L (PO ₄ ion: 7.2 g/L) sodium pyrophosphate (Na ₄ P ₂ O ₇ 10H ₂ O) 3.0 g/L (P ₂ O ₇ ion: 1.2 g/L) water-soluble polymer (3) 2.0 g (solid)/L average degree of polymerization = 2, in formula (I), X ¹ and X ² = -C ₂ H ₅ , Z =-CH ₂ N(CH ₂ CH ₂ CH ₂ OH) ₂ , average substituent Z substitution number = 0.6, adjust pH = 4.0 with aqueous sodium hydroxide solution.

Comparative Example 1

The same D and I aluminum alloy cans were cleaned according to Example 1.

The surface after cleaning was sprayed with the surface treatment aqueous solution (8) having the following composition and heated to 60° C. in 5 times, each time lasting 4 seconds, with an interval of 5 seconds. Contact time totaled 40 seconds. The resin coating formed on the surface of the drying can was cleaned as in Example 1.

Surface treatment aqueous solution (8) 75% phosphoric acid (H ₃ PO ₄ ) 10.0 g/L (PO ₄ ion: 7.2 g/L) water-soluble polymer (1) (see Example 1) 2.0 g (solid)/L pH =3.0 adjusted with sodium carbonate aqueous solution

Comparative Example 2

The same D and I aluminum alloy cans were cleaned according to Example 1.

The cleaned can was immersed at 60° C. for 30 seconds with an aqueous surface treatment solution (9) having the following composition.

The resin coating formed on the can surface was washed and dried as in Example 1.

Surface treatment aqueous solution (9) 75% phosphoric acid (H ₃ PO ₄ ) 1.0 g/L (PO ₄ ion: 0.72 g/L) water-soluble polymer (1) (see Example 1) 2.0 g (solid)/L pH =7.0 adjusted with aqueous sodium hydroxide solution

Comparative Example 3

The same D and I aluminum alloy cans were cleaned according to Example 1.

The cleaned tank was immersed in the surface treatment aqueous solution (10) having the following composition at 60° C. for 5 seconds.

The resin coating formed on the can surface was washed and dried as in Example 1.

Surface treatment aqueous solution (10) 75% phosphoric acid (H ₃ PO ₄ ) 10.0 g/L (PO ₄ ion: 7.2 g/L) sodium pyrophosphate (Na ₄ P _{2 O 7 10H 2} O) 1.0 g/L (P ₂ O ₇ ion: 0.4 g/L) water-soluble polymer (1) (see Example 1) 0.05 g (solid)/L

pH = 4.0 was adjusted with aqueous sodium carbonate.

Comparative Example 4

The same D and I aluminum alloy cans were cleaned according to Example 1; the cleaned cans were immersed in the surface treatment aqueous solution (11) having the following composition at 60° C. for 20 seconds.

The resin coating formed on the can surface was washed and dried as in Example 1.

Surface treatment aqueous solution (11) 95% sulfuric acid (H ₂ SO ₄ ) 2.0 g/L (SO ₄ ion: 1.9 g/L) sodium pyrophosphate (Na ₄ P ₂ O ₇ 10H ₂ O) 10 g/L (P ₂ O ₇ ion: 0.4 g/L) water-soluble polymer (1) (see Example 1) 0.05 g (solid)/L pH=3.5, adjusted with aqueous sodium carbonate.

Comparative Example 5

The same D and I aluminum alloy cans were cleaned according to Example 1.

The cleaned can was immersed in the surface treatment aqueous solution (12) having the following composition at 60°C for 30 seconds.

The resin coating formed on the can surface was washed and dried as in Example 1.

Surface treatment aqueous solution (12) 75% phosphoric acid (H ₃ PO ₄ ) 1.0 g/L (PO ₄ ion: 0.72 g/L) sodium pyrophosphate (Na ₄ P ₂ O ₇ -10H ₂ O) 1.0 g/L (P ₂ O ₇ ion: 0.4 g/L)

Water-soluble polymer (4) 2.0 g (solid)/liter Average degree of polymerization = 5, in formula (I), X ¹ and X ² = -C ₂ H ₅ , Z = -CH ₂ SO ₃ H, average substitution Substitution number of group -CH ₃ SO ₃ = 0.6, pH = 4.0, adjusted with aqueous sodium hydroxide solution.

Comparative Example 6

The same D and I aluminum alloy cans were cleaned according to Example 1.

The cleaned can was immersed in the surface treatment aqueous solution (13) having the following composition at 60° C. for 30 seconds.

The resin coating formed on the surface of the drying can was cleaned as in Example 1.

Surface treatment aqueous solution (13) 75% phosphoric acid (H ₃ PO ₄ ) 1.0 g/L (PO ₄ ion: 0.72 g/L) sodium pyrophosphate (Na ₄ P ₂ O ₇ 10H ₂ O) 1.0 g/L (P ₂ O ₇ ion: 0.4 g/L) water-soluble polymer (5) 2.0 g (solid)/L pH = 4.0, adjusted with aqueous sodium hydroxide solution.

The extract (5) is shown in formula (IV).

The composition of the surface treatment aqueous solution (13) is as described in Japanese Unexamined Patent Publication (kokai) No. 4-66671.

Comparative Example 7

The same D and I aluminum alloy cans were cleaned according to Example 1.

The cleaned can was immersed in a surface treatment aqueous solution (14) having the following composition at 60° C. for 30 seconds.

The resin coating formed on the can surface was washed and dried as in Example 1.

Aqueous surface treatment solution (14). 75% phosphoric acid (H ₃ PO ₄ ) 1.0 g/L (PO ₄ ion: 0.72 g/L) sodium pyrophosphate (Na ₄ P ₂ O ₇ 10H ₂ O) 1.0 g/L (P ₂ O ₇ ion: 0.4 g/l) water-soluble polymer (6) 0.4 g (solid)/l pH = 4.0 adjusted with aqueous sodium hydroxide solution.

Polymer (6) is as described in Japanese Unexamined Patent Publication (kokai) No. 2-608 and represented by formula (V).

Comparative Example 8

The same D and I aluminum alloy cans were cleaned according to Example 1.

The surface treatment aqueous solution obtained by dissolving 2% (by weight) of a non-chromate type surface treatment agent manufactured by Nihon Parkerizing K.K. under the trademark Arogin404 in water was heated to 40° C. and divided into 3 times at intervals of 5 seconds for 5 seconds each time. Spray it on the cleaned tank surface in seconds. The total contact time was 25 seconds. The resin coating on the surface of the drying tank was cleaned as in Example 1.

test results

Table 1

Table 1 clearly shows that the surface-treated aluminum alloy cans obtained by using the surface treatment method of the present invention and its polymer composition in Examples 1-7 have good corrosion resistance, coating adhesion and mobility. However, the surface-treated aluminum alloy cans obtained in Comparative Examples 1-8 using surface treatment solutions different from the present invention were not satisfactory in at least one of corrosion resistance, coating adhesion, and mobility.

As described above, the polymer composition and surface treatment method of the present invention effectively form a chemical conversion resin coating having good corrosion resistance and peel strength on the surface of aluminum-containing metal materials.

When the polymer composition and the surface treatment method of the present invention are applied on aluminum-containing metal cans produced by the stretch-iron method before coating and printing, the specific resin coating formed not only gives the can surface a good Excellent anti-corrosion performance and coating adhesion, and significantly improved mobility, which is very important for the smooth transfer of cans by means of conveyors.

Furthermore, since the polymer composition and the surface treatment solution suitable for the method of the present invention are free of chromium and fluorine, the present invention is advantageous in that the waste water treatment system is less burdened.

Claims (7)

1. be used for aluminium-containing metal material is carried out the surface-treated aqueous composition, wherein contain (a) phosphate ion, (b) condensed phosphate ion and (c) water-soluble polymers shown at least a general formula (I):

X in the formula ¹And X ²Represent a kind of hydrogen atom, C of being selected from respectively independently of one another _1-5Alkyl and C _1-5The group of hydroxyalkyl; Y ¹And Y ²Represent independently of one another respectively a kind of be selected from hydrogen atom and formula (III) and (II) shown in the group of substituting group Z: R in the formula ¹, R ², R ³, R ⁴And R ⁵Represent a kind of C of being selected from respectively independently of one another _1-10Alkyl, C _1-10The group of hydroxyalkyl, the substituting group Z that is attached in the polymerized unit on the phenyl ring separately can be same to each other or different to each other, the mean number that is attached at the substituting group Z on the independent phenyl ring in the polymerized unit is 0.2-1.0, it is the mean polymerisation degree of 2-50 that n represents value, and the mixed weight between phosphate ion (a), condensed phosphate ion (b) and the water-soluble polymers (c) is than (a): (b): (c) be 1-30: 0.1-10: 0.1: 20.

2. the aqueous composition of claim 1, wherein phosphate anion is derived by at least a material that is selected from phosphoric acid, alkali metal phosphate and ammonium phosphate and is formed.

3. the aqueous composition of claim 1, wherein the polycondensation phosphate anion is derived by the material of at least a an alkali metal salt that is selected from tetra-sodium, tripolyphosphate, four polyphosphoric acids and above-mentioned acid and ammonium salt and is formed.

4. the surface treatment method of aluminium-containing metal material, comprising the following step:

(A) make the pH value that contains (a) phosphate ion, (b) condensed phosphate ion and (c) at least a water-soluble polymers be 6.5 or lower surface treating aqueous solution under 30-65 ℃, contact 5-60 second altogether with the aluminium-containing metal material surface, this water-soluble polymers (c) is shown in general formula (I):

X in the formula ¹And X ²Represent a kind of hydrogen atom, C of being selected from respectively independently of one another _1-5Alkyl and C _1-5The group of hydroxyalkyl; Y ¹And Y ²Represent independently of one another respectively a kind of be selected from hydrogen atom and formula (II) and (III) shown in the group of substituting group Z:

With

R in the formula ¹, R ², R ³, R ⁴And R ⁵Represent a kind of C of being selected from respectively independently of one another _1-10Alkyl, C _1-10The group of hydroxyalkyl, the substituting group Z on the independent phenyl ring can be same to each other or different to each other in the polymerized unit with being attached at, the mean number that is attached at the substituting group Z on the independent phenyl ring in the polymerized unit is 0.2-1.0, it is the mean polymerisation degree of 2-50 that n represents numerical value, and the mixed weight between phosphate ion (a), condensed phosphate ion (b) and the water-soluble polymers (c) is than (a): (b): (c) be 1-30: 0.1-10: 0.1: 20.

(B) resin coating that forms on the washing aluminium-containing metal material surface;

(C) resin coating after the heat drying washing.

5. the method for claim 4, wherein surface processing solution contains 1-30 grams per liter phosphate ion (a), 0.1-10 grams per liter condensed phosphate ion (b) and 0.1-20 grams per liter water-soluble polymers (c), and the pH value of this solution is 2.0-6.5.

6. the method for claim 4, wherein aluminium-containing metal material floods 5-60 second in surface processing solution.

7. the method for claim 4, wherein surface processing solution in two steps or more multistep be sprayed on the aluminium-containing metal material surface with the interval of 2-5 second, spraying with last 5-60 second altogether at interval.