JPS59197594A - Anode aluminum oxide surface sealing treatment - Google Patents

Abstract

Processes for sealing anodised aluminium carried out in a bath having a pH of at least 7 and in the presence of a smut,inhibiting additive have been discovered to give rapid, efficient sealing without the formation of bloom. Examples of smut-inhibiting additives are phosphonates, benzene hexacarboxylic acid, and the reaction products of an aldehyde or dimethylol urea with sulphonated aromatic compounds. The reduction in time required for sealing reduces energy consumption in the anodising operation.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a novel method for treating aluminum surfaces by impregnating anodized aluminum in an aqueous solution, a novel composition for adding to said aqueous solution, and a novel method for impregnating said aluminum. Concerning water bath liquid.

Prior Art The corrosion and abrasion resistance of surfaces of aluminum and aluminum alloys is improved by anodizing them to form a substantially anhydrous layer of deposited aluminum oxide. [) The surface that has undergone the treatment shown on the right [
anodized surface. Anodizing is carried out in four distinct ways, for example by applying a direct current in a dilute aqueous solution of sulfuric acid, or an organic acid such as oxalic acid, or a mixture of sulfuric acid and an organic acid. These coatings can be colored by impregnation in a solution of a suitable dye or by treatment with alternating current in an electrolyte containing a metal salt. or in a solution such as a mixture of sulfophthalic acid or sulfosalicylic acid and sulfuric acid.

The oxide layer formed by the above-mentioned anodic oxidation has a porous structure and completely seals the metal surface.
A process known as The sealing process typically involves hydration of the anodized metal lamb in hot or boiling water, which causes the oxide layer to expand and seal the pores in the oxide structure. Whatever the sealing mechanism, the durability of an anodized surface is significantly increased by sealing the anodized surface.

One drawback associated with sealing treatments is that they affect not only the pores in the oxide layer (but also the surface of the oxide layer). This surface layer tends to have a layer of material that is visually unappealing (and detracts from the metal's useful properties). Usually removed by processing before sale.

Although the use of alkaline sealing baths is known to significantly accelerate the sealing process, the use of acidic baths, such as J)H in the sealing bath, is known to significantly accelerate the sealing process. Sm B. It is carried out in a bath which is usually maintained within the range of
A sealing time of 9 minutes is required to obtain a sufficient seal.

In recent years, in an attempt to overcome the problem of smut formation, additives to sealing baths have been described that are required to inhibit smut formation, and these additives are referred to below as anti-smut additives (anti-smut additives). Smutting addi
We will call it the tives month.

Examples of anti-smut additives include British Patent No. t2 Og, 'I
2 Hiro issue, 1.30 Tsuyu gg issue, 33A on the 13th Otsu
No. 1.391.1g No. 9, No. 1:'%/L59
? No. 1S7747 and British Patent Application Ser.

Structure of the Invention Recently, we have selected a sealing treatment for the anodic oxide film (
Both contain one type of smut-inhibiting additive and have a low
H7. It has been found that this can be done quickly, effectively and without the formation of large amounts of smut by impregnating the anodized surface in an aqueous medium with O2. Thus, according to one aspect of the invention, the pH is at least 7. '
A method for treating an anodized aluminum surface is provided which comprises impregnating the surface of anodized aluminum into an aqueous medium having an effective amount of seven smut-inhibiting additives.

Additives useful in the process of the present invention are smut-inhibiting additives selected to avoid the formation of smut during the novel alkaline sealing process. The smut-inhibiting additives of the present invention are not effective as all known additives in new alkaline sealing baths, and the smut-inhibiting additives are effective as anti-smut additives in acidic sealing processes according to the prior art. It is distinguished from known smut sealing additives in that it does not require a smut-sealing additive. For clarity, the term "smut-inhibiting additive" is used hereinafter in reference to the additives effective in the novel sealing process of the present invention.

The sealing process of the present invention is performed under the conditions described above and results in an acceptable smut-free sealed coating in less time than the time that sealing would be achieved using known equivalent sealing processes for smut. It is advantageous in that it can be The energy requirements of the method of the present invention can be significantly reduced since the sealed material must be maintained at elevated temperatures without the need for chemical or mechanical removal of the smut. When the bath temperature is 9!C or higher, the anodic oxidation layer becomes weaker than 7.
per micron/5 minutes or less, preferably/! 5 minutes or less, optimal V? - can be achieved in θ0 minutes or less. The sealing speed is 9S if the process is carried out at a temperature lower than 9S °C.
℃ or higher. In general, the sealed temperature should be less than or equal to gooC, since the rate of sealing decreases unacceptably at temperatures below gooC. The sealing temperature is preferably 93°C.
It is the darkness of the boiling point of the bath. The temperature in the pressurized system is 700℃
For example, the temperature may be 710°C, and//! r℃
Even can be used.

The method of the invention can be carried out under the conditions described above without the formation of smut during the sealing process. A smut-free product is one in which no smut is visually detectable on the product.

A product that is considered smut-free may contain fine particles of smut that can be detected by careful inspection, but does not detract from the overall appearance of the encapsulated product. .

The process according to the invention can be carried out under the conditions described above so as to seal the product to the desired degree.

Anodized aluminum used in construction and exposed under weathering conditions is usually sealed as efficiently as possible to maximize the corrosion resistance of the anodized aluminum. The quality of sealing can be evaluated using 7 types of standard tests in 3 classes: acid test weight loss, die spot (dye adsorption) test and conductivity test or 2s or more. These tests can be performed using the following techniques.

These standard measurement methods are based on the relevant British Standards (Bri
5 standards). The method used in the present invention is (1) Weight loss test in phosphoric acid/chromic acid - British Standard Filter 11.1: Par) 3: /qg/(ISO3
210-/97ri). The overall maximum allowable loss of the coating under the test conditions is generally θ, 3m & Am2 (30rn9/dm
2); (11) Die spot (dye absorption M) test (using acid A and dye B) - British Standard +/, g/:not (-t);
5: / q g, 2 (ISO2lI 1
(11D Anodic oxide coating) Conductivity test for determining the change in thickness of - British Standard TT/s;
It is expressed as the product of the film thickness in microns μm, and SO
A value of O or less satisfies British Standard/A15.

Next, appropriate values, preferred values, and optimal values for the above-mentioned tests are shown.

Appropriate value 0.3 (30) 2
, A; 00 suitable value θ, 2 (,20)
/ Rio.

Optimal value θ, / (10) 0
300 The criterion used to evaluate the quality of the seal for the purposes of the present invention is at least a suitable value of weight loss in the acid test.

Is the sealed pH at least? , o, more preferably at least 7.5 or g, o. Although higher pH promotes rapid sealing of the anodized coating, it can have a detrimental effect on the quality of the anodized coating and may also promote the formation of smut. The maximum pH of the bath varies with bath composition and operating temperature, but is generally 70.
．． 0 or less, preferably 7.5 or less, most preferably 9.
It is less than or equal to θ. Therefore, the pH of the sealing bath is preferably maintained at a value within the range of 7.0 to 9°0, for example q, s, g, 3.

The smut-inhibiting compound effective in the confining pressure treatment of the present invention must be water-bathable and must not have an adverse effect on the quality of the seal.
Although compounds that inhibit crystal growth in alkaline aqueous media when present in amounts of 0 ppm are potentially valuable as smut-inhibiting additives, not all known threshold treatments inhibit smut formation. or are not useful as smut-inhibiting additives in the process of the present invention to retard the sealing process.

Not all compounds are equally effective as anti-smut additives. Under conditions known to favor smut formation, such as high alkalinity and elevated temperatures, some compounds do not sufficiently inhibit smut formation even when present in large amounts.

However, such compounds can work well under less smut-forming conditions and are more useful in combination with other smut-inhibiting additives that are more effective under certain conditions. Spiky smut-inhibiting additives useful in the process of the present invention include dextrins (commercially available dextrins, particularly the KB rotational viscometer (Brookfield) as described in British Patent No. 130U, 2gg).
l rotary viscometer), 20°G
Dextrins with a solution viscosity of SO to 00 centiboise (CP); acrylic acid, methacrylic acid and water-soluble polymers derived therefrom;
For example, British Patent No. 731. The polyyos and lignin sulfonates having a viscosity of up to o,q s cp when measured in nico-normal sodium hydroxide at 20° C. and a concentration of 0.7% as described in Specification No. 33 O. (includes all of the geninsulphonates described in British Patent No. 13A 336); benzenepentacarboxylic acid, benzenetetracarboxylic acid, hexacarboxylic acid, cyclohexanetetracarboxylic acid and cyclohexanehexacarboxylic acid Acids such as cycloaliphatic or aromatic polycarboxylic acids having q to A carboxyl groups per molecule, or their water-soluble salts such as alkali metal salts, alkaline earth metal salts, ammonium salts and alkanolamine salts, especially the water-soluble salts described in British Patent No. 1JT'/767, certain hydroxyl carboxylic acids such as gallic acid and sugar acids; one or more Reaction products of the above-mentioned sulfonated aromatic compounds with aldehydes and/or dimethylol ureas or mixtures of formaldehyde and urea (UK Patent Application No. S/θ% 927: Select the reaction product from the group consisting of a.

There are seven kinds of IY′i, two or more kinds of water-soluble salts. Each of these acids or salts forms seven or more complexes with the covalent metal. It is known that a relatively large number of phosphonic acids form complexes with a-valent metals. It is preferable to use compounds corresponding to the following general formula: HOP-C-PO, R2(I) 5 H (wherein R is a phenyl group or an alkyl group having l' to S carbon atoms. ] or R2PO,R2 (in the formula, R1 and R2 each represent a hydrogen atom or an alkyl group having 1 to 2 carbon atoms, and R3
represents a hydrogen atom, an alkyl group or a phenyl group having 1 to 5 carbon atoms) or Ri CXY \ N-CxY-Po H(III) / HPO-CXY [wherein X and Y are each a hydrogen atom or a carbon atom/
Represents an alkyl group having from 1 to 5 pieces, R4 is P○, R5
or an alkyl group having 1 to 7 g carbon atoms or the following groups CXY-PO,H2 (wherein n is an integer of O or 1-3, and X and Y are as defined above) or CXYPOH (wherein X and Y are as defined above)] or 5 R20, P-C-COOH"" H, -C-COOH (wherein R5 is a hydrogen atom, a methyl group or -CH2CH
2C0OH group].

Examples of hydroxyalkanediphosphonic acids of the general formula (I) that can be used in the treatment of the present invention are /-hydroxypropane-/
, /-diphosphonic acid, l-hydroxybutane-/, /-
Diphosphonic acid, l-hydroxypentane-/, /-diphosphonic acid and h/-hydroxyhexane-/, /-diphosphonic acid and /-hydroxy-1-phenylmethane-
/,/-diphosphonic acid and preferably /-hydroxyethane-/,/-diphosphonic acid. General formula (Examples of phosphonic acids are l-aminoethane-/, /-diphosphonic acid, l-amino-7-phenylmethane-7, /-diphosphonic acid, dimethylaminoethane-/, /-diphosphonic acid,
They are propyl-aminoethane-/,/-diphosphonic acid and butylaminoethane-/,/-diphosphonic acid. Examples of the phosphonic acid of general formula (e) are aminotrimethylenephosphonic acid, hexamethylenediaminetetrakis(methylenephosphonic) acid, ethylenediaminotetramethylenephosphonic acid, diethylenetriaminopentamethylenephosphonic acid,
Al with n-propyliminobis(methylenephosphonic) acid and aminotri(copropylene-2-phosphonic acid). Examples of phosphonic acids of general formula (IV) are phosphonosuccinic acid, /-phosphono-/-methylsuccinic acid and -bosphonobutane-/,J,4()licarboxylic acid.

Particularly valuable smut-inhibiting additives for use in the present invention are phosphonic acids, particularly ethylenediaminotetramethylenephosphonic acid, hexamethylenediaminetetrakis(methylenephosphonic) acid, n-propyliminobis(methylenebosbon)ic acid, and benzenehexacrylic acid. Reaction products of carboxylic acids and their salts and sulfonated aromatic compounds with aldehydes or dimethylol urea or both (or mixtures of formaldehyde and urea) mAh, 'Mtnidiphenyl, phenyltoluene, dimethyldiphenyl, diphenyl ether, company name diphenyl sulfide, cyphenylsulfoquinto, cyhydroxydiphenyl sulfone,
The reaction products or sulfonated aromatic compounds formed by the sulfonation reaction of diphenylene oxide, diphenylene sulfite and hibisphenol with aldehydes or dimethylol urea or both or mixtures of formaldehyde and urea are In the case of sulfonated derivatives, it is the reaction product formed by reacting them with dimethylol urea or a mixture of formaldehyde and urea.

Suitable sulfonated aromatic compounds include sulfonated diphenyls, sulfonated dimethyl sulfates, sulfonated diphenyl ethers, as well as sulfonation reaction products of dimethyloleurea (or mixtures of formaldehyde and urea), unsubstituted phenols, and cresols. be.

Preferred aldehydes used to prepare the reaction product are acetaldehyde and formaldehyde, more preferably formaldehyde.

Preferably, when the reaction product is formed from the reaction: IC with a mixture of formaldehyde and urea, the formaldehyde/urea molar ratio is less than 2//.

Preferred reaction products are those formed by the reaction of formaldehyde with compounds that do not contain halogens or hydroxyl groups or by the reaction of sulfonated phenols with dimethylol urea. More preferred is a reaction product of formaldehyde and a compound of the following formula (2): R1u.

(In the formula, R4 represents a hydrogen atom, an alkyl group having 7 to 3 carbon atoms, a hydroxyl group, or a halogen atom, and X is directly bonded or CH.

or -802-, where n is the average value in the range /~g).

When the mixture for forming the reaction product is a mixture of sulfonated phenol, sulfonated cresol or sulfonated naphthol and dimethylol urea (or a mixture of formaldehyde and urea), further compounds such as heptenols and naphthols may be incorporated into the product by polymerization with formaldehyde.

Sulfonated aromatic compounds are known and can be prepared according to known methods. For the sulfonation reaction of the compound of formula (g), preferably /
-2 mol (more preferably /S mol) of sulfuric acid is used.

The reaction of compound No. 2 with formaldehyde or dimethylol urea is known and can be carried out according to known methods.

Phosphonic acid smut-inhibiting additives should be used in combination with monovalent metals M2+ for effectiveness;
The molar ratio of the +/phosphonate group is small (both 2// and -
For example, the molar ratio of monovalent metal ions is the theoretically required amount V to form a complex with all of the phosphonate present.
If the required amount of monovalent metal ions is not present in the sealing bath in the form of calcium and magnesium salts dissolved in tap water, for example, divalent metal ions/phosphones must be present. It is necessary to add sufficient soluble salts of monovalent metals to raise the molar ratio of acid groups to at least all It is.

In some cases, it appears that certain monovalent metal ions can deactivate phosponate salts. If such an effect is observed, add sufficient phosphonate to X to form a complex with the deactivated metal ion, and then add an appropriate amount of an acceptable monovalent phosphonate along with an additional phosphonate. Addition of metal salts is effective in suppressing smut formation. Generally, it is preferable to use calcium salt, magnesium salt, nickel salt or cobalt salt as the monovalent metal salt. Examples of ions that deactivate phosphonic acid compounds and whose presence is therefore undesirable are ferric and cupric ions. In general, ions that form strong complexes with phosphonates are smut inhibitors, and it is particularly preferred to use ethylenediaminotetramethylene phosphonic acid or a water-soluble salt thereof, especially its magnesium salt, as a smut inhibitor.

The amount of smut inhibitor present in the sealing bath will vary depending on the nature of the inhibitor. The minimum effective amount sufficient to inhibit smut formation during the sealing process is usually determined experimentally. Formation of a sealed oxide surface with satisfactory quality (e.g. adjustment of one or more parameters affecting the efficiency of the sealing bath, if accompanied by the formation of a gas mat), e.g. It may be necessary to increase the amount of smut control additive in the bath or to select a more effective smut control additive.

By way of example, suitable smut-inhibiting additives such as benzenehexacarboxylic acid, /-hydroxyethane-/, /
-Diphosphonic acid and ethylene diamino tetramethylene phosphonic acid doors are sealed/~shio θo ppm range, e.g. Ω~300 ppm, more preferably YC is sealed! ;-
It is 200 ppm. The effective amount will vary depending on the smut inhibitor selected and will be determined experimentally under the conditions normally used in the sealing process. The amount for a suitable smut inhibitor is j~SθOppm for benzenehexacarboxylic acid.
and in the case of ethylenediaminotetramethylenephosphonic acid, it is S~/00 ppm. The use of too much smut inhibitor can have a detrimental effect on the quality of the anodized coating, and therefore too much of the inhibitor can have a detrimental effect on the quality of the anodized coating. It is preferable to avoid the use of If the encapsulated pH is relatively high, the maximum flow of smut suppressant that can be tolerated without damage to the anodized coating is increased.

Addition of a water-soluble base to the sealed product is usually necessary to maintain the pH of the sealed product above t, o, preferably within the above-mentioned preferred range. Preferred bases for use in the present invention are Lewis bases. Examples of suitable bases that can be used are triethanolamine, sodium borate, sodium carbonate, sodium bicarbonate, monoethanolamine, jetanolamine, hexamine and mixtures thereof. The most preferred base for use in this invention is triethanolamine. If desired, technical grade triethanolamine containing gel/-luene and minor amounts of monoethanolamine can be used. It is preferable to avoid adding a base that can inhibit the sealing process. Therefore, it is not preferable to use bases which liberate phosphate ions, silicate ions and fluoride ions when precipitated in water.

The sealing process of the present invention can be performed with deionized water or tap water. The use of deionized water is advantageous because the sealing process proceeds better without complications. However, in industrial-scale processing, the encapsulation inevitably becomes contaminated by carryover of material from previous processing steps, such as anodizing baths and subsequent rinsing steps. Although a certain amount of this contaminant may be tolerated, the efficiency of the sealing process is reduced and the sealant must eventually be discarded.

The use of tap water to construct the sealant is disadvantageous because the inorganic substances dissolved in the tap water do not adversely affect the efficiency of the sealing process. The presence of dissolved inorganic substances also causes the formation of homogeneous precipitates in the sealing bath, and this solid precipitate is
Forms an unsightly, gaping film on the polarized surface. This tendency is most common when the smut inhibitor consists of the aforementioned phosphonic acids or bosvonic acid salts. Adhering solids can usually be removed by rinsing with water, but it is preferable to operate the sealing bath under conditions that completely avoid the need for the rinsing step. We have found that the tendency to form solid materials can be reduced by adding a field 1fj7 activator to the encapsulation. The amount of surfactant can vary over a wide range, for example from /pl)III to 1017/71. A preferred additive is carboxymethyl cellulose (hereinafter referred to as CMC).

Additions of CMo 3 ppm ~/00 ppm are often sufficient to prevent the formation of solid materials in the sealing bath.

The sealing bath may also contain conventional additives, such as additives known to inhibit dye leaching, such as nickel acetate.

It is also advantageous for the sealing treatment bath to contain a wetting agent,
The presence of a wetting agent increases the efficiency of the sealing process. A relatively small amount of wetting agent, eg sealed, eg 2.0-. 2000ppm
can be used. If heavy metal ions that impair the efficiency of the sealing process are present in the sealing bath, for example due to the addition of tap water or contamination from other parts of the anodizing equipment, effective operation of the sealing bath will require that the metal This can be extended by adding reagents that can form complexes with the ions.

A suitable example of such a reagent is citric acid. The reagent is effective when present in an amount significantly less than that required to form a complex with the metal ion present in the sealing bath. It is also advantageous to include a buffer to help control the t/ipH of the sealing bath. Suitable buffers include acetic acid and formic acid salts.

It is convenient and preferable to add the various components of the sealing treatment bath separately as desired. and form a further aspect of the present invention.

Concentrates include the aforementioned small amount (both 7 types of smut inhibitors, IJ
υContains less description (also consists of /8 bases).

Optionally, the concentrate contains salts of organic acids such as acetic acid, other additives such as nickel acetate, and other compatible components of the sealing bath to adjust the pH of the concentrate. Additives such as nickel acetate are preferably dissolved in the concentrate, for example by addition of triethanol [xi] to form a water-soluble compound.

In a preferred embodiment of the treatment of the present invention, the pH of the sealing treatment bath is
is established by adding the concentrate to water and maintained within the desired range by adding further reagents as the sealing process progresses.

Examples of the invention The present invention will be explained below with reference to Examples.

In the following examples, the sealing treatment bath uses the above-mentioned method,
The encapsulated product was further evaluated by visual inspection and any velvety bloom visible to the naked eye was considered unsatisfactory.

The test pieces used in the following examples were subjected to alkaline corrosion (
S%NaOH + additives) and anodized in sulfuric acid [sulfuric acid/
7s/l/l, temperature/g-, 20℃, 0.0/5
A/cm2 (/, tA/dm2)] L, type AOA3 aluminum alloy with a 20 micron thick anodized coating.

Each test was repeated on an uncolored specimen to measure the sealing process quality and dyed black (using a standard anodizing dye) before the sealing process to facilitate detecting the bloom of the surface coating. This was carried out on the test piece.

Example/ (4) Standard deionized water sealing treatment (comparative example) pH of sealing treatment bath: Temperature of A O sealing treatment bath = 9g°C 0, S 9U6 4t
Muco Large amount of frame/, θ 3.2
0/-23 Da Lots of Bloomco, 0 3
33 / , 23 large amount of Bloomda, 0 kotg / 7g
A large amount of bloom smut was observed after 0.5 min/micron.

CB) pH with deionized water + 2 ml/l/g of eryethanolamic acid. Adjusted to θ (comparative example) pH of sealing bath: g, o Temperature of sealing bath = 9
g0C O,! i 900/-1 3
S Bloom/, 0 g00
/ , 2,1 Bloom, 2.0
300//A
Bloomsmat is 0. ! Formation occurred within f minutes/micron.

(C) Ammonium salt of ethylenediamine-tetra[methylenephosphonic] acid Ωθpp to the sealing bath of (B)
m and nickel in the form of nickel sulfate/Oppm
(Example).

Sealing processing time Admittance stain spot acid weight loss
Product (min/cuspid chron) 0,! ; goo 0-/j/
No bloom/, θ Hirooo o
Details No bloom, 0. 2
g0 0 /7 No bloom No smut was observed.

Example - (A) CaC0,/! ; Total hardness cvv stuffed jar labeled Oppm (South
5tafford-shire) tap water (comparative example).

pH of sealing treatment bath: b, o Temperature of sealing treatment bath:
goC /, 0 coooo gu Ag
A large amount of bloom λ, θ 9θ0 . 2
4t/ large amount of Fushitomu (B) (A)l
/C -2ml171 of triethanolamine and Oppm of ethylenediaminetetra(methylenephosphonic) acid were added to the sealing bath used (Example) pH of the sealing bath @ g, , 2 Temperature of the sealing bath: 9 g'C 0,3+20oo lI xg
No bloom /, o 11g0 /-,
2-297-Room fHshi2.0', too
/, 2 No bloom-free female mats were observed.

Example 3 Mellitic acid [benzene hexacarboxylic acid] in the amount shown in the following table was completely added to deionized water. The pH of the sealing bath was increased by adding triethanolamine.

of 100 S, g/, Ogoo
, 2-3 11g No bloom, l) 1
00 5. g ko, 0 300 /
-Ko 3 Otsu No Funrem ■ 100
gA; /, 0! fOθ /
30 F) ← Without M The results of ■ and ■ are comparative examples. The sealing obtained during the sealing treatment time used was not of satisfactory quality. The result (2) is an example, and a satisfactory sealing can be obtained in a very short time.

EXAMPLE A smut inhibitor and ethylene diamine tetrakis (methylene phosphone) were added to deionized water at the concentrations shown in the table below.

pH of sealing treatment bath: g, 3 Sealing time: 1 minute/micron 10 Hiro 600-//Otsu Oko's bloom Oda I, 0 θ-7mu 0 Large bloom 10
0! ;00 0-/23 Large Bloom These results demonstrate that phosphonates are ineffective as smut inhibitors in the absence of divalent metal ions.

Ethylenediaminetetrakis(methylenephosphonic) acid/
Nail magnesium salt was added such that the molar ratio of Mg2+ was //.

+2o g,b g9 0 7g
No bloom tl, o g, s da + 2 u 02 μ No bloom o o g, tsu
1I00/5g without film AOg, 7. 29.3 0. 2g
These results (no bloom) indicate that the phosphonates are effective as smut inhibitors in the presence of divalent metal ions.

The results at a concentration of borophonate b OmlA indicate that the presence of an excessive amount of smut inhibitor reduces the quality of the seals produced, and that this condition has an additional effect on the pH of the sealing bath.
It explains that it can be overcome by rising.

Example S A predetermined amount of one of phosphonates A, B, and C was added to a sealing bath consisting of deionized water and sufficient magnesium ions to obtain a molar ratio of phosphonate/42+/S. . The sealing time was 1 minute/micron.

A: hexamethylenediaminetetrakis(methylenephosphonic) acid B diethylenetriaminepentakis(methylenephosphonic) acid C: n-propyliminobis(methylenephosphonic) acid A 20, g,! 1100 0-/
2.3 \No bloom B 20
gJ Hirooo θ-/+2q No bloom Cyuo g,s Hiro00 0-/J
All additives A, B and C without O bloom are effective as gas mant suppressants.

Example 6 Sandos Corn'pa
Various strains of commercially available products sold under the trade name ANODAL SHI+ by A.N.Y.) were added to deionized water to form encapsulation baths. The sealing baths were tested at various pHs and sealing times as shown in the following table summarizing the results.

” ANODAJ, SH Engineering is an aqueous solution consisting of the reaction product of a sulfonated aromatic compound and an aldehyde or dimethylol urea (or a mixture of formaldehyde and urea).

Claims (1)

[Claims] / A method for sealing an anodized aluminum surface with substantially no formation of smuts, comprising impregnating the anodized aluminum surface in an aqueous medium at a temperature of less than A method for sealing an anodized aluminum surface, characterized in that the pH of the aqueous medium is kept low (to 7.0 with a maintenance power of 9), and the aqueous medium I contains an effective amount of a smut-inhibiting additive. 2. The method according to claim 7, in which sufficient sealing treatment can be carried out in 5 minutes or less per micron of thickness of the anodic oxidation layer. 3. The aqueous medium, that is, the sealing treatment bath contains dextrins. ;
Acrylic acid, 5-methacrylic acid, water-soluble polymers derived from acrylic acid or methacrylic acid or lignin sulfonate; cyclic J aliphatic polycarboxylic acid, aromatic polycarboxylic acid, cyclohexanehexacarboxylic acid:
, water-soluble bosphonic acids capable of forming complex compounds with divalent metals;
and a reaction product of seven or more sulfonated aromatic compounds with an aldehyde and/or dimethylol urea or a mixture of formaldehyde and urea. The method described in the range 1st term and 2nd term. H) The method according to claim 3, wherein the sealing treatment bath contains a euvalent metal together with a water-soluble phosphonic acid. S phosphonic acid m is /-hydroxypropane-7, /-
Diphosphonic acid, l-hydroxybutane-/, /-diphosphonic acid, /-hydroxy-/-phenylmethane-/, /
-,) bosonic acid, /-hydroxyethane-1,l-
Diphosphonic acid, l-aminoethane-/, /-diphosphonic acid, /-amino-/-7enylntane-l, /-diphosphonic acid, dimethylaminoethane-/, /-dibosphonic acid, propylaminoethane-/, /-diphosphonic acid , butylaminoethane-/,/-diphosphonic acid, aminotrimethylenephosphonic acid, ethylenediaminotetramethylenephosphonic acid, diethylenetriaminopentamethylenephosphonic acid, hexamethylenediaminetetrakis(methylenephosphonic) acid, n-propyliminobis(methylene phosphonic] acid, aminotri(2-propylene-cophosphonic) acid, phosphosuccinic acid, /-phosphono-/-methylsuccinic acid and l-phosphonobutane-/, 2.F tricarboxylic acid. The method described in Scope No. D. B. A patent claim in which the phosphonate is selected from the group consisting of ethylenediaminotetramethylenephosphonic acid, hexamethylenediaminetetrakis(methylenephosphonic) acid, and n-propyliminobis(methylenephosphonic) acid. 7. The method according to claim 3, wherein the sealing bath contains benzene hexacarboxylic acid. g. The sealing bath contains 5 to soo ppm of benzene hexacarboxylic acid. 9. The method according to claim 7 or claim g, wherein the sealing treatment bath is maintained at pH 7.0 to 10.0. IO sealing treatment. Any one of claims 1 to 6, wherein the bath contains at least one divalent metal ion and a phosphonate with a low divalent metal ion/phosphonate molar ratio (both 2/1). 71. The method according to claim 70, wherein the molar ratio of divalent metal ion/phosphonate is at least /2. The method according to claim 10 or 11, wherein the method according to claim 10 or 11 is selected from the group consisting of: /3 The method according to claim 72, wherein the divalent metal ion is magnesium. /4L The pH of the sealing treatment bath is 7.0 to 10.0. The method according to any one of claims 1 to 6 or claims 9 to 73. 13. The pH of the sealing treatment bath is 7.0. The method of claim 14', wherein the smut-inhibiting additive is present in an amount of 9.0 to 300 ppm. 77. The method of claim 76, wherein the agent is present at a value of S to 10 theta ppm0. 71 M Masahi fM Bath casiphenyl, phenyltoluene, dimethyldiphenyl, diphenyl ether, diphenyl cyphenyl, diphenyl sulfoxide, dihydroxydiphenyl sulfo/, oxidized cyphenylene/, diphenylene sulfide and mixtures of bisphenol and aldehyde and/or dimethylol urea or formaldehyde and urea. If the sulfonated aromatic compound is a sulfonated derivative of phenol, cresol or naphthol, the reaction product of the sulfonated aromatic compound with dimethylol urea. The method according to claim 3, which contains one or more kinds. 〃 The method according to claim tgJA, wherein the sealing treatment bath contains a reaction product of O0θ/~s, ol17J. λθ Claims 1 to 1' in which the sealing treatment bath contains a surfactant? The method described in any of the paragraphs. -21 The method and method described in claim 20, wherein the surfactant is carboxymethylcellulose. , 2 U.Claim 1g in which the sealing treatment bath contains carboxymethyl cellulose at S~/00 ppm
The method described in section. 23. A concentrate for addition to a sealing treatment bath, characterized in that the concentrate contains a small amount (both of a sumant' inhibitor and a water-soluble base).