CN108842149A - The method for handling ferrous metal substrate - Google Patents

Abstract

The method for disclosing processing and coating ferrous metal substrate such as cold-rolled steel, hot-rolled steel and electrolytic zinc-coated steel sheet.These methods include contacting ferrous metal substrate with aqueous pretreatment compositions, and the composition includes：(a) IIIB and/or Group IVB metallic compound；(b) phosphate anion；(c) water.It is also disclosed that removing the ex situ methods of de-iron from pretreatment baths.

Description

The method for handling ferrous metal substrate

The application be on 2 28th, 2014 the applying date, application No. is 201480010256.9, entitled " processing The divisional application of the method for ferrous metal substrate ".

The related application of cross reference

The application is that the part of the U.S. Patent application No.13/313473 submitted on December 7th, 2011 is continued, the U.S. Patent application No.13/313473 is on September 25th, the 2008 U.S. Patent application No.12/237770 submitted (now as beauty State patent No.8097093 is promulgated) continuation, what U.S. Patent application No.12/237770 required to submit on September 28th, 2007 The equity of U.S. Provisional Patent Application Serial No.60/975957, which is incorporated herein by reference.

Invention field

The present invention relates to the methods of processing ferrous metal substrate such as cold-rolled steel, hot-rolled steel and electrolytic zinc-coated steel sheet.The present invention is also It is related to coated ferrous metal substrate.The invention further relates in the presence of the product to be coated by the pretreatment compositions and work as The pretreatment baths are, when pretreatment baths are on processing line, the method for de-iron to be removed from the pretreatment baths when offing normal.

Background information

Corrosion resistance is improved using protective coating on the metallic substrate and paint adhesion is universal.For coating The routine techniques of such substrate includes the technology being related to phosphate radical conversion coatings and the metal pretreated substrate of washing lotion containing chromium. Typical phosphate radical conversion coatings are operated with the phosphate radical of about at least 1000 parts/million parts (" ppm "), and which results in useless Object handles problem.Therefore, the composition using such phosphate radical and/or containing chromate causes environment and health problem.

It therefore, it has been developed to no chromate and/or the pretreatment compositions without phosphate radical.Such usual base of composition In chemical mixture, reacts in some manner with substrate surface and in connection form protective layer.For example, based on IIIB or The pretreatment compositions of person's Group IVB metallic compound have become more popular recently.

However, when by processing ferrous metal base based on the pretreatment compositions of IIIB or Group IVB metallic compound Ferric iron (Fe when bottom, in processing more metal based on iron, in the pretreatment compositions bath foam⁺³) concentration with when Between and increase.Specifically, the solubility (Fe from substrate⁺²) Tie Tong crosses Fe⁺²Concentrations build-up, oxidation and then anti-with oxygen and water It answers, and becomes insoluble (Fe⁺³).Resulting insoluble iron rust, that is, iron oxide (III) (Fe of hydration₂O₃·nH₂) and/or hydrogen O Aluminum oxide/iron oxide (III) (FeO (OH)), flocculation, and insoluble iron rust particle is existing when processing part is slightly agitated for the phase Between resist precipitating.Therefore, which can adhere to or deposit in substrate, and be carried to subsequent add Work step is rapid (especially when filter device is unavailable), such as the electrocoat bath (it is used to deposit organic coating) in downstream.It is such Cross contamination can deleteriously influence the performance of such then electrodeposited coating.

Therefore, practice conventional in industry is that the periodic dilution pretreatment baths are used as in advance to reduce the concentration of soluble iron Anti- measure, and replenisher is added into the pretreatment baths, to supplement bath ingredient and regain coating ability.In some cases In, which must remove from processing line, to carry out from the method to derust thereon.Alternatively, the pretreatment baths are necessary It was discharged every 1-2 weeks, and supplements fresh bath foam.These practice each of be it is expensive, this is attributed to apparent production Object loss, waste processing and inconvenience.

It is desirable, therefore, to processing ferrous metal substrate is provided and removes the improved method of soluble iron, solution It has determined at least some aforementioned problems.

Summary of the invention

In some aspects, the present invention relates to the methods of coating ferrous metal substrate.

In some aspects, the method for the coating ferrous metal substrate includes：(a) by ferrous metal substrate and containing water pretreatment Composition contact, the pH of the composition are 4-5.5 and include：(a) IIIB and/or Group IVB metallic compound；(b) phosphate radical Ion；(c) water, wherein the amount of the IIIB and/or Group IVB metallic compound in the pretreatment compositions is 10- 500ppm metal, and the weight ratio of IIIB and/or Group IVB metal and phosphate anion is at least in the pretreatment compositions 0.8：1；Wherein the phosphate anion is maintained in pretreatment compositions bath with following amount：(i) it is enough to basically prevent Insoluble iron rust is formed in bath；(ii) is not enough to prevent coverage rate to be at least 10mg/m²IIIB or Group IVB metal film It deposits in ferrous metal substrate；(iii) causes the weight ratio of phosphate radical and ferric ion to be 1-1.8：1；Then (b) The substrate is contacted with the coating composition comprising film-forming resin, to form coated metallic substrates, is shown corrosion-resistant Performance.

Certain in terms of other, the method for the coating ferrous metal substrate includes：(a) by ferrous metal substrate with it is aqueous pre- Treatment compositions contact, the pH of the composition are 4-5.5 and include：(a) IIIB and/or Group IVB metallic compound；(b) phosphorus Acid ion；(c) water, wherein the amount of the IIIB and/or Group IVB metallic compound in the pretreatment compositions be 10-500ppm metal, and in the pretreatment compositions weight ratio of IIIB and/or Group IVB metal and phosphate anion be to Few 0.8：1；Wherein the phosphate anion is maintained in pretreatment compositions bath with following amount：(i) it is enough substantially to prevent Insoluble iron rust is only formed in bath；(ii) is not enough to prevent coverage rate to be at least 10mg/m²IIIB or Group IVB metal Film deposits in ferrous metal substrate；(iii) leads to the weight ratio of phosphate radical with the other soluble iron in ferrous state It is 1.8-10：1；Then (b) contacts the substrate with the coating composition comprising film-forming resin, to form coated metal Substrate shows corrosion resistance.

Certain in terms of other, the present invention relates to the methods that de-iron is removed from pretreatment baths comprising in the pretreatment baths It is the step of progress when offing normal.

In some aspects, it is used for from the pretreatment for containing pretreatment compositions (it includes IIIB race and/or IV race metals) Except the ex situ methods of de-iron include in bath：(a) pH of the pretreatment baths is reduced at least 0.2；(b) phosphate anion is added (a) in the pretreatment baths in；(c) pH of the pretreatment baths in (b) is increased at least 0.2.

Certain in terms of other, for from pre- containing pretreatment compositions (it includes IIIB race and/or Group IVB metals) Except the ex situ methods of de-iron include in processing bath：(a) acid adding reduces the pH of the pretreatment compositions into the pretreatment baths To lower than 4.0；(b) phosphate anion is added in the pretreatment baths in (a)；(c) pH of the pretreatment baths in (b) is increased To 4.0-5.5.

The invention further relates to the substrates for thus handling and coating.

Detailed description of the invention

Fig. 1 and 2 is the diagram of the result of observed embodiment 3；

Fig. 3 is the diagram of the result of observed embodiment 4；

Fig. 4 is the diagram of the result of observed embodiment 5；With

Fig. 5 is the diagram of the result of observed embodiment 6.

Specific embodiment

For purpose described further below, it should be understood that the present invention can be using different alternative variations and step time Sequence, in addition to there is specific opposite regulations place.In addition, being indicated other than in addition to any operation embodiment or wherein indicated otherwise Such as whole numbers of the amount of ingredient used in description and claims are understood in the case where whole be to use term " about " modified.Therefore, unless the contrary indication, otherwise below description and the appended claims in the number that illustrates Parameter is approximate number, can according to the present invention the sought desired performance obtained and change.At least, and be not intended to using Doctrine of equivalents limits the scope of the claims, each digital parameters should at least according to the numerical value for the effective digital reported and It rounds up technology by using common and explains.

Although the digital scope and parameter that illustrate wide scope of the present invention are approximate numbers, the number in a particular embodiment Value is reported as precisely as possible to report.However any numerical value substantially contains the mark as present in their own test measurement Certain errors that quasi- deviation is necessarily formed.

Also, it is to be understood that the purpose of any digital scope described here is to include in whole subrange therein. Such as range " 1-10 " purpose is included in the whole between (and including end value) minimum value 1 and the maximum value 10 Subrange, that is, have minimum value equal to or more than 1 and maximum value is equal to or less than 10.

In this application, singular use includes that plural number and plural number cover odd number, unless otherwise expressly provided.In addition, In the application, "and/or" is indicated using "or", unless otherwise expressly provided, but can clearly be used in some cases "and/or".

In this application, term " offing normal " indicates that the product to be coated by pretreatment compositions is not present in pretreatment baths In, it is not intended that the pretreatment baths must be removed from processing line.

In this application, the total amount of term " total iron " or " total Fe " expression iron in pretreatment baths, including but not limited to three Valence iron (Fe⁺³) iron and ferrous iron (Fe⁺²) iron.

In this application, unless clearly indicated to the contrary, otherwise when claim pretreatment compositions " not having substantially " have Body group timesharing, its discussed material of expression if any, are then present in composition as accidental impurity.Change speech It, which, which is not intended that, is added in composition, but can be with a small amount of or inessential horizontal presence, because it is to make For the composition component part meant impurity and carry.In addition, when claiming specific group of pretreatment compositions " absolutely not " Timesharing, it indicates that discussed material is not present in composition at all.

As previously mentioned, certain embodiments of the invention are related to a kind of method for handling ferrous metal substrate.For the present invention Suitable ferrous metal substrate include being frequently used for car body, automobile component and for example small metal parts (packet of other products Include fastener, that is, nut, bolt, screw rod, pin, nail, clip, button etc.) those of assembling.Suitable ferrous metal Substrate specific example includes but is not limited to cold-rolled steel, hot-rolled steel, the steel coated with zinc metal, zinc compound or kirsite, Such as electrolytic zinc-coated steel sheet, electro-galvanized steel, galvanized steel and Zinc alloy electroplating steel.In addition, the iron class handled by the method for the invention Metallic substrates can be the cut edge of substrate, be to handle and/or coat in its remaining surface in other ways.Root It can be in the form of the component of such as sheet metal or production according to the ferrous metal substrate that method of the invention coats.

Ferrous metal substrate to handle according to the method for the present invention can clean first remove degreasing, foul or its His foreign matter.This is often carried out using medium or strong alkaline cleaner, such as is commercially available and to be commonly used in metal pre- Processing method.The example for being suitable for the invention alkaline cleaner includes Chemkleen^TM163,177,611L and 490MX, Each of which is available commercially from PPG Industries, Inc.Such detergent often water flushing after and/or before.

As previously mentioned, certain embodiments of the present invention are related to the method for handling metallic substrates comprising by metallic substrates It is contacted with the pretreatment compositions comprising IIIB and/or Group IVB metal.As used herein, term " pretreatment combination size Object " refers to such composition, reacts after contacting with substrate with substrate surface, and chemically changes substrate surface, And in combination form protective layer.

Frequently, which includes carrier, often water-bearing media, so that the composition can be in IIIB The either form of Group IVB metallic compound solution in the carrier or dispersion.In these embodiments, solution or point Granular media can be contacted by any a variety of known technologies with substrate, such as dip-coating or submergence, spraying, intermittent spray, leaching Then spraying is applied, subsequent dip-coating, brushing or roller coating are sprayed.In certain embodiments, the solution or dispersion are when application The temperature of 50-150 ℉ (10-65 DEG C) is in when on to metallic substrates.Time of contact is often -5 minutes 2 seconds, such as 30 seconds -2 Minute.

As used herein, term " IIIB and/or Group IVB metal " refer to the CAS periodic table of elements IIIB race or The element of person's Group IVB, for example, such as Handbook of Chemistry and Physics, shown in the 63rd edition (1983).? In the case where being applicable in, metal itself can be used.In certain embodiments, using IIIB race and/or Group IVB metal compound Object.As used herein, term " IIIB and/or Group IVB metallic compound " refers to such compound comprising at least A kind of IIIB race of the CAS periodic table of elements or the element of Group IVB.

In certain embodiments, IIIB used in the pretreatment compositions and/or Group IVB metallic compound be zirconium, The compound or its mixture of titanium, hafnium.Suitable zirconium compounds includes but is not limited to hexafluoro zirconate, alkali metal and ammonium salt, Zirconium carbonate ammonium, zirconium oxycarbonate, zirconyl nitrate, carboxylic acid zirconium and carboxylic hydroxy group's zirconium, such as zirconic acid hydrofluoro, zirconium acetate, oxalic acid zirconium, second Alkyd zirconium ammonium, zirconium lactate ammonium, citric acid zirconium ammonium and its mixture.Suitable titanium compound include but is not limited to fluotitanic acid and its Salt.Suitable hafnium compound includes but is not limited to hafnium nitrate.

In certain embodiments, the amount of the IIIB and/or Group IVB metallic compound in pretreatment compositions bath It is at least 10ppm metal, for example, at least 20ppm metal, at least 30ppm metal or in some cases at least 50ppm metal (being measured as metal element).In certain embodiments, IIIB and/or Group IVB metallic compound are in the pretreatment combination size Amount in object bath is not more than 500ppm metal, such as is not more than no more than 150ppm metal, or in some cases 80ppm metal (measures) as metal element.The amount of IIIB and/or Group IVB metal in pretreatment compositions may be at institute It states between any combination of value, including described value.

As previously mentioned, including phosphate anion for the pretreatment compositions in certain embodiments of the method for the present invention. In certain embodiments, which is phosphoric acid, such as 75% phosphoric acid, but other sources of phosphate anion The present invention it is expected that, such as sodium dihydrogen phosphate or disodium hydrogen phosphate.In certain other embodiments, side of the present invention The pretreatment compositions of method there is no phosphate anion.

As previously mentioned, phosphate anion is in pretreatment compositions bath in certain embodiments of the method for the present invention Maintenance dose be enough to basically prevent to form insoluble iron rust in bath.As used herein, term " holding " expression regulation phosphorus The amount of acid ion, and adjust as needed to basically prevent being formed insoluble iron rust.As used herein, wording " basically preventing forming insoluble iron rust " indicates to prevent insoluble iron rust (that is, including but not limited to hydrated ferric oxide (III) (Fe₂O₃·nH₂O) and/or iron oxide (III)-hydroxide (FeO (OH))) formed in bath, and arrive such degree, That is, naked eye does not see the orange or reddish brown colored appearance for showing that such compound is formed in bath.More precisely, at this In certain embodiments of invention, phosphate anion is maintained in bath with such amount, is enough to be complexed from handled iron class The soluble iron that metal substrate surface etches, to form ferric phosphate (III) (FePO in bath₄), this generates have to whiten The bath foam of appearance, rather than with iron rust there are related orange or reddish brown colored appearances, and this results in insoluble silt Slurry, can be used conventional filtration aggregates and removes from bath.Therefore certain embodiments of the present invention limit ferric iron (Fe⁺³) Amount (from ferrous metal substrate) in bath, which can be used for becoming insoluble iron rust, which can be deposited on base On bottom, and it is brought to subsequent process equipment such as downstream nozzle, pump, flushed channel and the electropaining for depositing organic coating Bath.As previously mentioned, such cross contamination can have an adverse effect to the performance of the coating then deposited in this way.

In certain embodiments of the method for the present invention, which is also maintained at the pretreated group with such amount It closes in object bath, is not enough to prevent coverage rate (total film weight) to be at least 10mg/m², for example, at least 100mg/m²Or some 100-500mg/m in situation²IIIB or Group IVB metal film deposition to ferrous metal substrate on.It has been found that and especially exists Under bath pH used in the present invention, next soluble iron is etched from ferrous metal substrate in complexing to form the phosphoric acid of ferric phosphate (this is undesirable to the phosphate anion of IIIB or Group IVB metal in the presence of radical ion (this is desired) and complexed bath Because this will be prevented on enough IIIB or Group IVB metal film deposition to ferrous metal substrate) between there is delicate Balance.

It has been found that in the composition, is based on every 1 parts by weight ferric iron (Fe⁺³) there is 1-1.8, such as 1.2- for ion When the phosphate anion of 1.6 parts by weight, it is sufficient to basically prevent forming above-mentioned insoluble iron rust, while be not enough to prevent from covering Rate is at least 100mg/m², for example, at least 10mg/m²IIIB or Group IVB metal film deposition to ferrous metal substrate on.Cause This, in certain embodiments of the method for the present invention, which is maintained at such level in bath, leads to phosphoric acid The weight ratio of radical ion and ferric ion is 1-1.8：1, it is 1.2-1.6 in some cases：1.If phosphate anion with The weight ratio of ferric ion is less than 1：1, then bath in phosphate radical it is very few, and cannot basically prevent bath in formed it is above-mentioned not Dissolubility iron rust.If the weight ratio of phosphate anion and ferric ion is greater than 1.8：1, then the amount of phosphate anion can be enough to prevent Only on enough IIIB or Group IVB metal film deposition to ferrous metal substrate.In the pretreatment compositions phosphate anion with The ratio between ferric ion can be between any combination of described value, including described value.

In addition, the phosphate anion is maintained at such level in bath in certain embodiments of the method for the present invention, It causes the weight ratio of IIIB and/or Group IVB metal and phosphate anion in bath to be at least 50：1, in some cases at least 25：1, in some cases at least 12.5：1, in some cases at least 3：1, and in some cases at least 2：1.If The weight ratio of IIIB and/or Group IVB metal and phosphate anion is less than 2：1, then there can be excessive phosphate radical in bath, it is thus right It has a negative impact in by the ability on enough IIIB or Group IVB metal film deposition to ferrous metal substrate.

It is apparent that because pretreatment compositions of the invention include in some cases 20-500ppm IIIB and/or Group IVB metal, such as 30-150ppm or the IIIB of 30-80ppm and/or Group IVB metal in some cases, so at this In certain embodiments of inventive method, relatively few phosphate anion is frequently present in the bath, this is because certain The phosphate anion is maintained at such level in bath in embodiment, leads to IIIB and/or Group IVB metal and phosphorus in bath The weight ratio of acid ion is at least 2：1, in some cases at least 3：1.As a result in certain embodiments, such bath packet Phosphate anion containing not more than 30ppm, such as 10-30ppm.However, there are a small amount of phosphate anion have shown that it is logical Crossing within up to several months or several years prevents from forming insoluble iron rust in the pretreatment baths, in certain embodiments for example, by De-iron is removed from the pretreatment baths, and the useful bath service life can be made a significant impact.

As described above, when by processing iron eka-gold based on the pretreatment compositions of IIIB or Group IVB metallic compound When belonging to substrate, due to handling more based on the metal of iron, ferric iron (Fe in pretreatment compositions bath⁺³) concentration at any time And increase.It the result is that such bath has accumulated insoluble iron rust, can deposit in processed substrate, and be brought to then Procedure of processing.In order to avoid this, such bath often must be replaced periodically, in some cases once a week.However, The presence for being surprisingly found that aforementioned a small amount of phosphate radical can prevent from forming insoluble iron rust, without preventing enough IIIB And/or the formation of Group IVB metal film, so that the bath can run several months (can be indefinitely), without displacement.In this way A small amount of phosphate radical can will extend to such significant degree the bath service life, this be it is surprising and it is not anticipated that.In addition, with Phosphate anion a small amount of existing in this way results in the slurry of minimum, be prevented from insoluble iron rust more than offset, with So that waste treatment problem is not significant problem.

In certain embodiments, which also includes positive electric metal.As used herein, term is " just Electric metal " refers to the metal bigger than metallic substrates electropositive.It means that for the purposes of the present invention, term " positive electricity gold Belong to " it include such metal, it is less susceptible to aoxidize for the metal compared to processed metallic substrates.As this field skill Art personnel will be understood that, the oxidation tendency of metal is referred to as oxidation potential, are to be expressed with volt, and are relative to standard Hydrogen electrode is arbitrarily imparted 0 oxidation potential come what is measured.The oxidation potential of several elements is listed in the following table.If one The voltage value E* of kind element in the following table is greater than another element by comparison, then the element is less to hold compared to another element Oxidizable.

Element	Half-cell reaction	Voltage, E*
			Potassium	K++e→K	-2.93
Calcium	Ca2++2e→Ca	-2.87
			Sodium	Na++e→Na	-2.71
Magnesium	Mg2++2e→Mg	-2.37
			Aluminium	Al3++3e→Al	-1.66
Zinc	Zn2++2e→Zn	-0.76
			Iron	Fe2++2e→Fe	-0.44
Nickel	Ni2++2e→Ni	-0.25
			Tin	Sn2++2e→Sn	-0.14
Lead	Pb2++2e→Pb	-0.13
			Hydrogen	2H++2e→H2	-0.00
Copper	Cu2++2e→Cu	0.34
			Mercury	Hg2 2++2e→2Hg	0.79
Silver	Ag++e→Ag	0.80
			Gold	Au3++3e→Au	1.50

It is thus evident that such as situation of the invention, it is pre- for being included in this when the metallic substrates include ferrous metal Suitable positive electric metal in treatment compositions includes such as nickel, tin, copper, silver and gold and its mixture.

In certain embodiments, the source of positive electric metal is water-soluble metal salt in the pretreatment compositions.In this hair In bright certain embodiments, which is water-soluble copper compound.Water-soluble copper suitable for the present invention Close object specific example include but is not limited to copper cyanider, cuprous potassium cyanide, copper sulphate, copper nitrate, cupric pyrophosphate, cupric thiocyanate, Ethylene diaminetetraacetic acid copper disodium tetrahydrate, copper bromide, copper oxide, Kocide SD, copper chloride, copper fluoride, glucose saccharic acid Copper, copper citrate, Hamposyl L copper, copper formate, copper acetate, propionic acid copper, copper butyrate, copper lactate, cupric oxalate, phytic acid copper, Cupric tartrate, malic acid copper, succinic acid copper, malonic acid copper, maleic acid copper, copper benzoate, Cupric salicylate, aspartic acid copper, paddy Propylhomoserin copper, fumaric acid copper, phosphoglycerol copper, sodium copper chlorophyllin, cupric fluosilicate, cupric fluoborate and cupric iodate and homologous series Formic acid to the mantoquita of carboxylic acid of capric acid, the mantoquita of the polyacid of oxalic acid to suberic acid series and hydroxycarboxylic acid (including glycolic, Lactic acid, tartaric acid, malic acid and citric acid) mantoquita.

When the copper ion provided from such water-soluble copper compound as the impurity in the forms such as copper sulphate, copper oxide and It when precipitating, is preferably capable of that complexing agent is added, which inhibits the precipitatings of copper ion, thus stablize them as copper complex In the solution.

In certain embodiments, copper compound, which is added, is used as copper complex salt such as K₃Cu(CN)₄Or Cu-EDTA and It is added, can be stable in the presence of in composition with itself, but it may also form copper complex, it can be by by network The compound of mixture and indissoluble itself is combined and is stable in the presence of in the composition.Its example includes by CuCN and KCN The composition of combination or CuSCN and KSCN or KCN and the cyaniding copper complex that is formed, and pass through CuSO₄And EDTA2Na Combination and the Cu-EDTA complex compound that is formed.

About complexing agent, the compound that complex compound can be formed with copper ion can be used；Its example includes Quadrafos Such as sodium tripolyphosphate and hexa metaphosphoric acid；Amino carboxylic acid such as ethylene diaminetetraacetic acid, ethoxy ethylene amine triacetic acid And nitrilotriacetic acid；Hydroxycarboxylic acid such as tartaric acid, citric acid, gluconic acid and its salt；Amino alcohol such as triethanolamine；Vulcanization Close object such as thioglycolic acid and thiocarbamide and phosphonic acids such as itrile group trimethylene phosphonic, ethylene diamine four (methylene phosphonic acid) And hydroxy ethylene diphosphonic acid.

In certain embodiments, the positive electric metal such as copper is at least 1ppm, for example, at least 5ppm, or in some feelings It is that the amount of the total metal of at least 10ppm (measuring as metal element) is included in pretreatment compositions in condition.In certain implementations In scheme, the positive electric metal is to be not more than 500ppm, such as no more than 100ppm, or is not more than 50ppm in some cases The amount of total metal (measuring as metal element) is included in such pretreatment compositions.Positive electric metal is in the pretreated group The amount closed in object may be between any combination of described value, and including described value.

As indicated, it is 4.0-5.5 for the operation pH of the pretreatment compositions of the method for the present invention, is in some cases 4.0-5.0,4.5-5.5, or in other situations be still 4.5-5.0.The pH of the pretreatment compositions can be according to need It for example to be adjusted using any acid or alkali.

In addition to the foregoing components, it may include for the pretreatment compositions of the method for the present invention any a variety of other Optional components.It such as in certain embodiments, include that polyhydroxy function is cyclic annular for the pretreatment compositions of the method for the present invention Compound, if United States Patent (USP) No.6805756 is described in the 9th row to the 32nd row of the 4th column of the 3rd column, reference portion is incorporated herein As reference.However in other embodiments, it there is no for the pretreatment compositions of the method for the present invention or one Absolutely not any such polyhydroxy function cyclic compound in a little situations.

It in certain embodiments, include oxidant-accelerator for the pretreatment compositions of the method for the present invention, such as Those of described in the 52nd row to the 13rd row of the 5th column of the 4th column of United States Patent (USP) No.6805756, reference portion is incorporated herein by With reference to and United States Patent (USP) No.6193815 the 4th column the 39th row of 62 rows to the 5th column described in those of, reference portion is herein It is incorporated herein by reference.As a comparison, in other embodiments, which there is no or in some cases In absolutely not any such oxidant-accelerator.

In certain embodiments, which includes organic film-forming resin, such as alkanolamine and containing at least Those of the reaction product of the epoxy functional materials of two epoxy groups, such as be disclosed in United States Patent (USP) No.5653823；Packet The resin of hydroxy ester containing β, acid imide or sulfide functionality, be by prepared by resin use dihydromethyl propionic acid, Phthalimide or mercapto glycerol are mixed as other reactant；Bisphenol-A diglycidyl ether (as EPON880 is available commercially from Shell Chemical Company), dihydromethyl propionic acid and diethanol amine are with 0.6-5.0：0.05- 5.5：The reaction product of 1 molar ratio；Water-soluble and water-dispersible polyacrylic acid, such as United States Patent (USP) No.3912548 and Disclosed in 5328525；Phenolic resin, as described in United States Patent (USP) No.5662746；Water soluble polyamide is for example disclosed in WO95/ Those of in 33869；The copolymer of maleic acid or acrylic acid and allyl ether, as described in Canadian patent application 2087352； With water-soluble and water-dispersible resin, including epoxy resin, aminoplast, phenolic resin, tannic acid and polyphenylethyl phenol, As United States Patent (USP) No.5449415 is discussed.As a comparison, in other embodiments, which does not have substantially Have or organic film-forming resin absolutely not any in some cases, those one or more as escribed above.

It in certain embodiments, include fluorine ion, such as description in beauty for the pretreatment compositions of the method for the present invention In the 6th column 7-23 row of state patent No.6805756, reference portion is hereby incorporated by reference.In certain embodiments In, fluorine ion is introduced into composition by IIIB and/or Group IVB metallic compound.In certain embodiments, this is pre- Treatment compositions there is no or absolutely not any from addition to IIIB and/or Group IVB metal compound in some cases Source except object is introduced into the fluorine ion in the pretreatment compositions.

It in certain embodiments, include polysaccharide, such as description in the U.S. for the pretreatment compositions of the method for the present invention The 6th column 53-64 row (its reference portion is hereby incorporated by reference) and international application WO2005/ of patent No.6805756 In the 001158 17-23 row of page 3.As a comparison, in other embodiments, the pretreatment compositions there is no or Person's absolutely not any such polysaccharide in some cases.

In certain embodiments, for the pretreatment compositions of the method for the present invention include phosphate, fatty acid it is water-soluble Property macrogol ester and/or nitric acid, such as description is in the 6th column 31-63 row of United States Patent (USP) No.5139586, reference Part is hereby incorporated by reference.As a comparison, in other embodiments, the pretreatment compositions there is no or Absolutely not phosphate in some cases, the water-soluble polyethylene glycol ester of fatty acid and/or nitric acid.

In certain embodiments, include vanadium and/or cerium ion for the pretreatment compositions of the method for the present invention, such as retouch It states in the 47th row of the 2nd column United States Patent (USP) No.4992115 to the 29th row of the 3rd column (its reference portion is hereby incorporated by reference), and In U.S. Patent Application Publication No.2007/0068602.As a comparison, in other embodiments, the pretreatment compositions base Not or in some cases absolutely not vanadium and/or cerium ion in sheet.

In certain embodiments, for the pretreatment compositions of the method for the present invention include phosphorous acid, hypophosphorous acid and/or its Salt, such as description, in the 4th column 24-37 row of United States Patent (USP) No.5728233, reference portion is hereby incorporated by reference. As a comparison, in other embodiments, which there is no or absolutely not sub- in some cases Phosphoric acid, hypophosphorous acid and/or its salt.

It in certain embodiments, include Group IIA metal for the pretreatment compositions of the method for the present invention, such as description exists In the 3rd column 25-33 row of United States Patent (USP) No.5380374, reference portion is hereby incorporated by reference and/or IA race gold Belong to, such as describe the 66th row of the 2nd column in United States Patent (USP) No.5441580 into the 4th row of the 3rd column, reference portion is incorporated herein As reference.As a comparison, in other embodiments, which there is no or complete in some cases Entirely without any Group IIA metal and/or any IA race metal.

It in certain embodiments, include molybdenum compound for the pretreatment compositions of the method for the present invention, such as description exists In UK Patent Application GB2259920A.As a comparison, in other embodiments, the pretreatment compositions there is no or Person's absolutely not any molybdenum compound in some cases.

It in certain embodiments, include selected from following one or more for the pretreatment compositions of the method for the present invention The ion of metal：Scandium, yttrium, lanthanum, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium, such as description is in United States Patent (USP) To the 26th row of the 3rd column, reference portion is hereby incorporated by reference the 60th row of the 2nd column of No.5104577.As a comparison, at it In his embodiment, which there is no or be absolutely not selected from some cases following metal Any ion：Scandium, yttrium, lanthanum, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium.

The pretreatment compositions can optionally comprising other materials such as nonionic surface active agent and pre-process The conventional use of adjuvant in field.In water-bearing media, the alcohol example of such as at most about 8 carbon atoms of water-dispersible organic solvent Such as methanol, isopropanol may exist；The either monoalky lether of glycol ethers such as ethylene glycol, diethylene glycol or propylene glycol etc.. When it is present, water-dispersible organic solvent typically dosage at most about 10 volume %, the total volume meter based on water-bearing media.

Other optional materials include the surfactant for serving as defoaming agent or substrate wetting agents.

In certain embodiments, which also includes filler such as siliceous filler.The non-limit of suitable filler Qualitative example includes silica, mica, montmorillonite, kaolinite, asbestos, talcum, diatomite, vermiculite, natural and synthesis boiling Stone, cement, calcium silicates, alumina silicate, lagoriolite, aluminium silicate polymer, aluminium oxide silica gel and glass particle.In addition to siliceous filler it Outside, the substantially water-insoluble filler of other finely divided particles can also be used.The example of such optional filler includes charcoal Black, charcoal, graphite, titanium oxide, iron oxide, copper oxide, zinc oxide, antimony oxide, zirconium oxide, magnesia, aluminium oxide, curing Molybdenum, zinc sulphide, barium sulfate, strontium sulfate, calcium carbonate and magnesium carbonate.As a comparison, in other embodiments, the pretreatment combination size Object there is no or absolutely not any such filler in some cases.

In certain embodiments, which there is no or absolutely not chromic acid in some cases Salt and/or heavy phosphates such as trbasic zinc phosphate.As used herein, term " there is no " is being located in advance when for referring to It manages in composition there is no when chromate and/or heavy phosphates, indicates these substances in the composition not with such journey Degree (that is, they cause environmental pressure) exists.As used herein, term " absolutely not " is when for referring to that there is no weights When metal phosphate and/or chromate, there is no heavy phosphates and/or chromate in expression in the composition.

As will be appreciated, in certain embodiments, for the pretreatment compositions in the method for the present invention substantially by following Composition, or be made up of in some cases：(a) IIIB and/or Group IVB metallic compound such as zirconium compounds；(b) phosphorus Acid ion source such as phosphoric acid；(c) water.In certain other embodiments, for the pretreatment combination size of the method for the present invention Object is made up of substantially, or is made up of in some cases：(a) IIIB and/or Group IVB metallic compound such as zirconium Compound；(c) water.In certain embodiments, such pretreatment compositions include passing through IIIB and/or Group IVB metal Compound is introduced into the fluorine ion in the pretreatment compositions.As used herein, wording "consisting essentially of" expression group Close the other components that object does not include any basic and new characteristic that substantial effect is of the invention.For mesh of the invention , it includes that any pretreatment compositions by substantial effect are used successfully to the method for the present invention that this, which indicates the pretreatment compositions not, In ability component.

In certain embodiments, the film coverage rate (total film weight) of the pretreatment coating composition residue is at least 10 Milli gram/m (mg/m²), such as 100-500mg/m²Or at least 50mg/m in some cases².The pretreatment coating Thickness can change, but it is usually very thin, and frequent thickness is less than 1 micron, it is that 1-500 receives in some cases Rice, and in other situations still, it is 10-300 nanometers, such as 20-100 nanometers.

In certain embodiments, which be used to remove soluble iron from pretreatment baths, so that this is pre- Processing bath there is no iron when ex situ methods are completed, and thus basically prevent being formed in the pretreatment compositions are bathed and run Insoluble iron rust.As used herein, term " there is no " is when for referring to that pretreatment compositions bath is running When iron, indicate that total iron amount is less than 10ppm.It as described here, in certain embodiments, should when the bath is run Pretreatment compositions bath there is no phosphate anion, such as in such pretreatment system, wherein the pretreatment baths Present in phosphate radical can negatively affect deposition of the pretreatment compositions in substrate.In such embodiments, from Ex situ methods in pretreatment baths except de-iron may be particularly useful in the pretreatment system that there is no phosphate anion, as A method of it basically prevents forming insoluble iron rust in pretreatment baths.In addition, as described here, in other certain implementations In scheme, pretreatment compositions bath includes phosphate anion, basically prevents being formed in pretreatment baths as one kind insoluble The method of property iron rust.In such embodiments, the ex situ methods that de-iron should be removed from pretreatment baths can be particularly useful as one Other or supplement method is planted, to basically prevent forming insoluble iron rust in the pretreatment baths.

As previously mentioned, in certain embodiments, the operation pH of the pretreatment baths is greater than 4.0, e.g. 4.2-5.5, excellent Select 4.5-5.0 and most preferably 4.8.It in certain embodiments, should be from pretreatment baths except the first step of the ex situ methods of de-iron It suddenly include the pH of the pretreatment baths being reduced at least 0.2, such as reduce at least 0.5 or at least 1.0, so that the pretreatment baths PH be reduced to 1.0-3.8 and preferred 2.5-3.3.In certain embodiments, the pH of the pretreatment baths be by acid adding to should It is reduced in pretreatment baths, including as not limiting example, Group IVB fluorine metal acid such as hexafluoro zirconate and hexafluorotitanic acid, Phosphoric acid, sulfuric acid, sulfamic acid, nitric acid and its mixture.

This from pretreatment baths remove de-iron ex situ methods certain embodiments in, reduce the pH's of the pretreatment baths First step is to be completed by the way that enough acid to be added in the pretreatment baths with reducing above-mentioned pH.

This from pretreatment baths remove de-iron ex situ methods certain embodiments in, second step includes by phosphate radical Ion is added in the pretreatment baths.In certain embodiments, the source of the phosphate anion can be as single hydrogen or dihydro Alkali metal orthophosphate and ammonium orthophosphate existing for type, including sodium dihydrogen phosphate as an example, disodium hydrogen phosphate and its mixed Close object.In certain embodiments, Zircobond Additive P is used as phosphate anion source, be it is a kind of available commercially from The sodium dihydrogen phosphate of PPG Industries, Inc., Euclid, Ohio.

This from pretreatment baths remove de-iron ex situ methods certain embodiments in, third step includes by oxidant It is added in the pretreatment baths.In such embodiments, which is peroxide compound, air, sodium nitrite, bromine Sour sodium and its mixture.In a preferred embodiment, which is hydrogen peroxide.

This from pretreatment baths remove de-iron ex situ methods certain embodiments in, the source of phosphate anion and oxygen The respective additional amount of agent is enough to cause to generate the pretreatment baths that there is no iron.

This from the certain embodiments of ex situ methods for removing de-iron in pretreatment baths, four steps includes by the pre- place The pH of reason bath increases at least 0.2.In embodiments, which is risen above into 4.0, such as 4.2-5.2,4.5-5.0, and 4.8.In certain embodiments, the pH be by by enough alkaline compositions (including the causticity as not limiting example Sodium, caustic potash and sodium hydroxide) be added in pretreatment baths come it is raised.In embodiments, which is Chemfil Buffer, one kind being obtained from PPG Industries, Inc., Euclid, and the commercial product of Ohio can be to be enough Realize it is desired operation pH amount come using.

In certain embodiments of ex situ methods of the present invention, additional amount of the phosphate anion in the pretreatment baths is enough It is complexed with the soluble iron come is etched from handled ferrous metal substrate surface, to form ferric phosphate (III) in bath (FePO₄), this generates the bath foams with whitening appearance, rather than to iron rust there are relevant orange or reddish brown colored appearance, And this results in insoluble slurry, which can be used routine filtration device and remove from bath.It offs normal in the present invention In certain embodiments of method, the 5th step includes that the pretreatment baths are filtered using such routine filtration device, to remove Remove the solid matter in the pretreatment baths, that is, ferric phosphate, iron oxide, iron hydroxide or any other insoluble slurry (its It is formed in the pretreatment baths).In certain embodiments, filtration step, which can follow closely, increases the pH of pretreatment baths at least 0.2.In certain other embodiments, after filtration step can be during balance, during balance, this insoluble slurry It is deposited to the bottom of pretreatment baths, such as 1-10 hours after the pH of the pretreatment baths is increased.

Therefore, ex situ methods of the invention eliminate the soluble iron (from ferrous metal substrate) in bath, can be used In becoming insoluble iron rust, which can be deposited in substrate, and be carried to subsequent processing unit (plant), such as downstream spray Mouth, pump, rinsing bath and the electrocoat bath for depositing organic coating.As previously mentioned, such cross contamination can deleteriously influence this The performance of the subsequent depositing coating of sample.However, it has surprisingly been found that the pH of pretreatment baths is fallen below into operation pH, And a small amount of phosphate radical above-mentioned and optional oxidant is then added, can substantially remove the iron in bath, thus prevent Insoluble iron rust is formed in the pretreatment baths, without prevent bath pH be increased to operation level after formed enough IIIB and/or Group IVB metal film, so that the bath can run several months (can be indefinitely), without displacement.Such step can Will bath the service life extend to degree apparent in this way be it is surprising and it is not anticipated that.

After contacting with preprocessing solution, which can be rinsed with water and dry.

In certain embodiments of the method for the present invention, after substrate is contacted with pretreatment compositions, it then with comprising The coating composition of film-forming resin contacts.Any suitable technology can be used for contacting substrate with such coating composition, Including for example brushing, dip-coating, flow coat, spraying etc..However in certain embodiments, as described in more detail below, such Contact includes electropaining step, wherein being deposited to electrodepositable composition in the metallic substrates by electro-deposition.

As used herein, term " film-forming resin " refers to such resin, can deposit in removing composition Any diluent or carrier after or after environment temperature or hot setting, at least one horizontal surface of substrate Form self-supporting continuous film.The conventional film-forming resins that can be used include but is not limited to be typically used in automotive OEM Coating material composition Object, automobile trimming coating composition, industrial coating composition, architectural coating compositions, coil coating composition and aerospace Those of coating composition etc..

In certain embodiments, which includes thermosetting film-forming resin.As used herein, term " thermosetting property " refers to such resin, after solidification or crosslinking irreversibly " fixed (set) ", the wherein aggretion type group The polymer chain divided is linked together by covalent bond.This performance is usually and for example often due to heat or radiation-induced combination The cross-linking reaction of object ingredient is related.Solidification or cross-linking reaction can also carry out at ambient conditions.Once solidification or crosslinking, then hot Thermosetting resin will not melt and not dissolve in solvent when applying heat.In other embodiments, which includes thermoplastic Property film-forming resin.As used herein, term " thermoplasticity " refers to such resin, and it includes do not pass through covalent bond to connect Aggretion type component and it is possible thereby to after the heating occur liquid flow and dissolve in solvent.

As previously mentioned, in certain embodiments, the substrate and the coating composition comprising film-forming resin are walked by electropaining Rapid contact, wherein being deposited to electrodepositable composition in metallic substrates by electro-deposition.It is processed in electrodeposition process Metallic substrates serve as electrode, and electric conductivity places electrode and contacts with ionic electrodepositable composition.In electrode and right There is electric current after (while contacting them with electrodepositable composition) between electrode, in a substantially continuous manner in Metal Substrate It deposited the coherent film of electrodepositable composition on bottom.

Electro-deposition usually carries out under 1 volt to several kilovolts, the constant voltage of typically 50-500 volt.Current density is usually 1.0 amperes -15 amperes/square feet (10.8-161.5 amperes per square meter), and tend to during electrodeposition process quickly It reduces, this suggests the formation of continuous self-insulating film.

It often include to be dispersed in water-bearing media for the electrodepositable composition in certain embodiments of the present invention Resin phase, wherein the resin mutually include：(a) containing the ionic electrodepositable resin of active hydrogen group, and (b) have and (a) Active hydrogen group have the curing agent of reactive functional group.

It in certain embodiments, include as master for the electrodepositable composition in certain embodiments of the present invention Want ionic (often cationic) electrodepositable resin containing reactive hydrogen of film forming polymer.Extensive a variety of electrodepositables Film-forming resin is known, and be can be used in the present invention, as long as the polymer is " water is dispersible ", that is, it is suitable In solubilising in water, dispersion or emulsification.The water dispersible polymer is ionic in nature, that is, the polymer will include Anionic functional group is to assign negative electrical charge, or as generally preferable, comprising cationic functional group to assign positive charge.

The example of film-forming resin suitable for anionic electrodepositable composition is alkali solubilising, polymerization carboxylic-containing acid Object, such as the reaction product or adduct of drying oil or semi-drying fatty acid ester and dicarboxylic acids or acid anhydrides；With aliphatic ester, The reaction product of unsaturated acids or acid anhydrides and any other unsaturated modified material (its further with polyol reaction).Together The hydroxyalkyl acrylate of sample suitably unsaturated carboxylic acid, unsaturated carboxylic acid and other at least one ethylenically unsaturated monomers are at least The interpretation that part neutralizes.Still the suitable electrodepositable film-forming resin of another kind includes alkyd resin-aminoplast vehicle, That is, the carrier containing alkyd resin and amine-aldehyde resins.Still another anionic electrodepositable resin combination includes tree The mixed ester of rouge polyalcohol, such as description is in the 9th column 1-75 row of United States Patent (USP) No.3749657 and the 10th column 1-13 row In, reference portion is hereby incorporated by reference.Other acid functional polymers, such as phosphated polycyclic oxygen can also be used Compound or phosphated acrylic polymer, as is known to persons skilled in the art.

As previously mentioned, often it is desirable that the ionic electrodepositable resin (a) containing reactive hydrogen is cationic, And it can be deposited on cathode.The example of such cationic film-forming resins includes the resin containing amine salt group, such as poly- The sour solubilizing reaction product of epoxides and primary or secondary amine, such as description is in United States Patent (USP) No.3663389；3984299； 3947338；With 3947339 in those of.Frequently, these resins containing amine salt group are and blocked isocyanate curing agent group What conjunction used.The isocyanates can be completely enclosed, and as described in United States Patent (USP) No.3984299 or the isocyanates can It to be partially enclosed, and is reacted with resin backbone, such as description is in United States Patent (USP) No.3947338.Equally, the U.S. is special Single-component composition described in sharp No.4134866 and DE-OS No.2707405 may be used as film-forming resin.In addition to epoxy- Except amine reaction product, film-forming resin can also be selected from cationic acrylic resins, such as description in United States Patent (USP) Those of in No.3455806 and 3928157.

Other than the resin containing amine salt group, the resin containing quaternary ammonium salt group can also be used, such as by organic polycyclic Oxide and tertiary amine reactant salt are formed by those, such as United States Patent (USP) No.3962165；3975346；Described in 4001101.Its The example of his cation type resin is the resin of the resin containing tertiary sulfonium group and the salt groups containing quaternary phosphine, such as describes respectively Those of in United States Patent (USP) No.3793278 and 3984922.It is also possible to using film-forming resin cured via transesterification, Such as description is in European application No.12463.In addition it is possible to use cationic composition, example as prepared by Mannich base As described in United States Patent (USP) No.4134932.

In certain embodiments, the resin being present in the electrodepositable composition is positively charged resin, it includes Primary and/or secondary amine groups, such as description is in United States Patent (USP) No.3663389；3947339；In 4116900.In United States Patent (USP) In No.3947339, the polyketimine derivative of polyamines such as diethylenetriamines or trien and polycyclic are aoxidized Object reaction.When reaction product acid is neutralized and is dispersed in water, free primary amine group is produced.Equally, when polycyclic oxygen When compound is reacted with excessive polyamines such as diethylenetriamines and trien, product of equal value is formd, and will Extra polyamines vacuum from reaction mixture strips, as described in United States Patent (USP) No.3663389 and 4116900.

In certain embodiments, presence of the ionic electrodepositable resin containing reactive hydrogen in electrodepositable composition Amount is 1-60% weight, such as 5-25% weight, the total weight based on electrodeposition bath.

As shown, the resin of the electrodepositable composition mutually often further includes curing agent, is used for and ionic The active hydrogen group of electrodepositable resin reacts.Such as closed organic multiple isocyanate and aminoplast curing agents are suitable for The present invention, but closed isocyanates is frequently preferred for use in negative electrode electro-deposition.

Amino resin (its preferred curing agent for being often used for anionic electrodeposition) is amine or amide and aldehyde Condensation product.The example of suitable amine or amide is melamine, benzoguanamine, urea and similar compound.In general, used Aldehyde be formaldehyde, but product can be made of other aldehyde such as acetaldehyde and furfural.The condensation product includes methylol or class As hydroxyalkyl, this depend on specific aldehyde used.Frequently, by these methylols by with alcohol for example containing 1-4 carbon it is former The single hydroxyl alcohol of son such as methanol, ethyl alcohol, isopropanol and n-butanol react to be etherified.Amino resin is with trade (brand) name CYMEL is available commercially from American Cyanamid Co. and with trade (brand) name RESIMENE available commercially from Monsanto Chemical Co.。

The aminoplast curing agents are often with the anionic electrodepositable resin containing reactive hydrogen with 5%-60% weight, example If the amount of 20%-40% weight is used together, total weight of the percentage based on resin solid in electrodepositable composition.

As shown, closing organic multiple isocyanate is commonly used as the curing agent in negative electrode electro-deposition composition.The polyisocyanate Cyanate can be it is completely enclosed, such as the 1st column 1-68 row of United States Patent (USP) No.3984299, the 2nd column and the 3rd column 1-15 It is described in row or partially enclosed, and reacted with main polymer chain, such as the 2nd column 65- of United States Patent (USP) No.3947338 68 rows, described in the 3rd column and the 4th column 1-30 row, reference portion is hereby incorporated by reference." closed " expression isocyanates Group is reacted with compound, so that the closed isocyanate groups of gained are stable for reactive hydrogen in environment temperature , but with the reactive hydrogen in the film forming polymer for the high temperature for being generally in 90 DEG C -200 DEG C be have it is reactive.

Suitable polyisocyanates includes aromatics and aliphatic polyisocyante, including alicyclic polyisocyanates, and generation Table example includes diphenyl methane -4,4'- diisocyanate (MDI), and 2,4- or 2,6- toluene di-isocyanate(TDI) (TDI), Including its mixture, to phenylene vulcabond, tetramethylene and hexamethylene diisocyanate, dicyclohexyl methyl hydride -4, 4'- diisocyanate, isophorone diisocyanate and phenylmethane -4,4'- diisocyanate and the more phenyl of polymethylene The mixture of isocyanates.Higher polyisocyanates such as triisocyanate can be used.Example will include triphenyl methane -4, 4', 4 "-triisocyanates.Can also use isocyanates and polyhydric alcohols such as neopentyl glycol and trimethylolpropane and with polymerize The prepolymer of object polyhydric alcohols such as polycaprolactone glycol and triol (NCO/OH equivalent proportion is greater than 1).

The polyisocyanate curing agent is typically with the cationic electrodepositable resin containing reactive hydrogen with 5%-60% weight Amount, such as the amount of 20%-50% weight are used together, the total weight of resin solid of the percentage based on electrodepositable composition Meter.

It in certain embodiments, should also include yttrium comprising the coating composition of film-forming resin.In certain embodiments, Amount of the yttrium in such composition is 10-10000ppm, such as no more than 5000ppm, and in some cases less In total yttrium (being measured as yttrium) of 1000ppm.

Soluble and insoluble yttrium compound can serve as yttrium source.Suitable for unleaded electrodepositable coating composition Yttrium source example be soluble organic and inorganic yttrium salts for example yttrium acetate, yttrium chloride, formic acid yttrium, yttrium carbonate, sulfamic acid yttrium, Lactic acid yttrium and yttrium nitrate.When yttrium is added in electrocoat bath as aqueous solution, yttrium nitrate (a kind of yttrium compound being easily obtained) It is preferred yttrium source.Other yttrium compounds suitable for electrodepositable composition are organic and inorganic yttrium compounds for example aoxidize Yttrium, yttrium bromide, yttrium hydroxide, yttrium molybdate, yttrium sulfate, yttrium silicate and yttrium oxalate.Organoyttrium complexes and yttrium gold can also be used Belong to.When yttrium is incorporated into electrocoat bath as the component of pigment paste, yttrium oxide is often preferred yttrium source.

Electrodepositable composition described here is in the form of aqueous dispersion.It is saturating that term " dispersion " is believed to be two-phase Bright, translucent or opaque resin system, wherein resin is in dispersed phase, and water is in continuous phase.Resin phase is put down Equal granularity is usually less than 1.0 and usually less than 0.5 micron, frequently less than 0.15 micron.

Mutually the concentration in water-bearing media is often at least 1 weight %, such as 2-60 weight % to resin, is based on aqueous dispersion The total weight of body.When such composition is in the form of resin concentrate, their common resin solid contents are 20- 60 weight %, the poidometer based on aqueous dispersion.

Electrodepositable composition described here is passed through frequently as bi-component and is supplied：(1) transparent resin is fed, and is usually wrapped The ionic electrodepositable resin (that is, principal film-forming polymer) containing reactive hydrogen is included, curing agent and any other water are dispersible , uncoloured component；(2) pigment paste generally includes one or more colorants (as described below), and water is dispersible to be ground Mill resin (it can be identical or different with principal film-forming polymer) and optional additive such as wetting aid or dispersion help Agent.

In certain embodiments, which is presented as the form of electrodeposition bath, such as this field Well known to technical staff, wherein component (1) and (2) are dispersed in water-bearing media, and it includes water and usual agglomerated solvent.As in the early time Described, an advantage of the present invention is that such bath can prevent from being polluted by iron rust, or even when filter device is not present It is also such.

As previously mentioned, in addition to water, which can also include agglomerated solvent.Useful agglomerated solvent is often Hydrocarbon, alcohol, ester, ether and ketone.Preferred agglomerated solvent is often alcohol, polyalcohol and ketone.Specific agglomerated solvent includes isopropanol, fourth Single ethyl of alcohol, 2-Ethylhexyl Alcohol, isophorone, 2- methoxyl group pentanone, ethylene glycol and propylene glycol and ethylene glycol, monobutyl and Single hexyl ether.The amount of agglomerated solvent is usually 0.01-25%, such as 0.05-5% weight, the total weight based on water-bearing media.

In addition, colorant and additives different when necessary such as surfactant, wetting agent or catalyst can wrap It includes in the coating composition for including film-forming resin.As used herein, term " colorant " is expressed as composition imparting Any substance of color and/or other opacity and/or other visual effects.Colorant can be in any suitable form It is added in composition, such as discrete particle, dispersion, solution and/or sheet.Single colorant or two kinds can be used Or more colorant mixture.

The example of colorant includes pigment, dyestuff and coloring agent, such as paint industry and/or is listed in Dry Color Those of in Manufacturers Association (DCMA) and special efficacy composition.Colorant may include for example subtle The solid powder of dispersion is insoluble, but wettable under conditions of use.Colorant can be it is organic or inorganic, And can be reunion or non-agglomerated.Colorant can by using abrasive media such as acrylic compounds abrasive media and It is incorporated to, its use is well known to those skilled in the art.

The example of pigment and/or color compositions includes but is not limited to the thick pigment of carbazole dioxazine, azo, monoazo, double Azo, naphthols AS, salt type (color lake), benzimidazolone, condensation product, metal complex, isoindolinone, isoindoline and more Ring phthalocyanine, quinacridone, purple cyclic ketones (perinone), diketopyrrolo-pyrrole, thioindigo blueness, anthraquinone, indanthrone, anthracene pyrimidine, Flavanthrone, pyranthrone, anthanthrone, dioxazine, triaryl carbon, quinophthalone pigments, the red (" DPPBO of diketopyrrolo-pyrrole It is red "), titanium dioxide, carbon black and its mixture.Term " pigment " and " colored filler " use in which can be interchanged.

The example of dyestuff include but is not limited to be solvent base and/or those of water base, such as phthalocyanine green or phthalocyanine blue, oxidation Iron, pucherite, anthraquinone, aluminium and quinacridone.

The example of toner includes but is not limited to the pigment being dispersed in the miscible carrier of water base or water, such as available commercially from The AQUA-CHEM 896 of Degussa, Inc., available commercially from Eastman Chemical, the Accurate Dispersions of Inc. The CHARISMA COLORANTS and MAXITONER INDUSTRIAL COLORANTS of branch company.

As described above, the colorant may be at the form of dispersion, including but not limited to nanoparticle dispersion.Nanometer Particle dispersion may include the nanoparticle colorants and/or coloring agent particle of one or more high degree of dispersion, which create Desired perceived color and/or opacity and/or visual effect.Nanoparticle dispersion may include colorant such as granularity It is, for example, less than 70nm less than 150nm, or the pigments or dyes less than 30nm.Nano particle can be by being less than with granularity The abrasive media of 0.5mm grinds the organic or inorganic pigment of deposit to produce.The example of nanoparticle dispersion and they Manufacturing method provided in United States Patent (USP) No.6875800B2, which is incorporated herein by reference.Nanoparticle dispersion can also To be produced by crystallization, precipitating, vapor condensation and chemistry friction (that is, being partly dissolved).In order to enable nano particle in coating The minimum that reassociates, can be used resin cladding nanoparticle dispersion.As used herein, " resin cladding is received Rice grain dispersion " refers to continuous phase, is wherein being scattered with discrete " composite particles ", it includes nano particles and the nanometer Resinous coat on particle.The example of the nanoparticle dispersion of resin cladding and their manufacturing method were June 24 in 2004 The U.S. Patent Application Publication 2005-0287348A1, the U.S. Provisional Application No.60/ that on June 24th, 2003 submits that day submits It is provided in the US Pat Appl Ser No.11/337062 that on January 20th, 482167 and 2006 submits, work is also incorporated herein For reference.

The example for the special efficacy composition that can be used includes such pigment and/or composition, and which create a kind of or more Kind appearance effect for example reflect, be pearly-lustre, metallic luster, phosphorescence, fluorescence, photochromic, light sensitivity, thermochromism, different with angle Color (goniochromism) and/or discoloration.Other special efficacy composition can provide other appreciable performances, such as impermeable Lightness or texture.In certain embodiments, special efficacy composition can produce color drift, so that the color of coating is in difference Angle changes when observing the coating.The example of color effect compositions provides in United States Patent (USP) No.6894086, herein It is incorporated herein by reference.Other color effect compositions may include transparent cladding mica and/or synthetic mica, coat dioxy SiClx, coated aluminum oxide, transparent liquid crystal pigment, liquid crystal coatings and/or any composition, wherein interference is by material infolding The generation of rate difference is penetrated, rather than generated because of the refractive index difference between material surface and air.

In certain embodiments, photosensitive composition and/or photochromic composition can be used, work as and be exposed to one kind Or its color is reversibly changed when various light sources.Photochromic and/or photosensitive composition can be by being exposed to certain wave Long radiation and activate.When the composition becomes excitation state, molecular structure changes, and the structure of the change shows difference In the new color of composition priming color.When removing radioactive exposure, photochromic and/or photosensitive composition may return to quiet Only state, wherein returning to the priming color of composition.In certain embodiments, the photochromic and/or photosensitive composition It can be colourless in non-sharp method state, and show color in excitation state.Panchromatic variation can at several milliseconds to a few minutes, Such as occur in -60 seconds 20 seconds.Photochromic and/or photosensitive composition example includes photochromic dyes.

In certain embodiments, the photosensitive composition and/or photochromic composition can connect in and/or at least portion Divide and is bonded on the polymer and/or polymer material of (such as being covalently bonded to) polymerizable components.With wherein photosensitive group Closing object can migrate out from coating, and crystallize some coatings into substrate on the contrary, certain embodiments according to the present invention, The photosensitive composition and/or light-induced variable colour cell for being connected to and/or being at least partly bonded on polymer and/or polymerizable components Object is closed from moving out at least in coating.The example of photosensitive composition and/or photochromic composition and their manufacturing method exist It provides, is hereby incorporated by reference in the US application serial No.10/892919 that on July 16th, 2004 submits.

In general, colorant can in the coating composition, to be enough to assign any of desired vision and/or colour effect Amount exists.The colorant can account for 1-65 weight %, such as 3-40 weight % or 5-35 weight %, and weight percent base In the total weight of composition.

After deposit, coating heating is often solidified to deposited composition.Heating or curing operation often exist 120-250 DEG C, such as 120-190 DEG C of temperature carries out 10-60 minutes periods.In certain embodiments, gained film Thickness is 10-50 microns.

As book is understood from the foregoing description, certain embodiments of the present invention further relate to prevent the iron rust of coating unit dirty The method of dye, or even be also such in the method for wherein coating ferrous metal substrate when filter device is not present.Certain In embodiment, such method includes using pretreatment compositions, and pH is 4-5.5, and including or some cases In, substantially it is made up of：(a) IIIB and/or Group IVB metallic compound；(b) phosphate anion；(c) water.In this hair In such embodiment of bright method, phosphate anion is in pretreatment compositions bath with the presence of such amount：(i) its foot To basically prevent forming insoluble iron rust in bath foam；(ii) is not enough to prevent coverage rate to be at least 10mg/ft²IIIB Or on Group IVB metal film deposition to ferrous metal substrate.In certain other embodiments, such method include it is a kind of from The ex situ methods of de-iron are removed in pretreatment baths, which includes IIIB race and/or Group IVB metal, in certain embodiments In, it there is no phosphate anion in operation, and in certain other embodiments include phosphate anion.This is offed normal Method includes step：(a) pH of the pretreatment baths is reduced at least 0.2；(b) phosphate anion is added to the pretreatment in (a) In bath；(c) oxidant is added in the pretreatment baths in (b)；(d) pH of the pretreatment baths in (c) is increased at least 0.2. In such ex situ methods for removing de-iron from pretreatment baths, insoluble iron rust can be removed substantially from the pretreatment baths. In certain embodiments, which further comprises the step of filtering the pretreatment baths using filter device.

As will also be appreciated that, the invention further relates to the methods of coating ferrous metal substrate.In certain embodiments, these Method includes：(a) ferrous metal substrate is contacted with aqueous pretreatment compositions, the pH of the composition is 4-5.5, and includes Or it is substantially made up of in some cases：(i) IIIB and/or Group IVB metallic compound；(ii) phosphate anion； (ii) water, wherein maintenance dose of the phosphate anion in pretreatment compositions bath is enough to basically prevent to be formed not in bath Dissolubility iron rust；Then (b) contacts substrate with the coating composition comprising film-forming resin, shows corrosion resistance to be formed Coated metallic substrates.In some other embodiments, such method includes：(a) when the pretreatment baths are offed normal, from this De-iron is removed in pretreatment baths；Then (b) contacts the ferrous metal substrate with aqueous pretreatment compositions, the pH of the composition It is 4-5.5, and includes or be substantially made up of in some cases：(i) IIIB race and/or Group IVB metal；With (ii) water；Wherein the pretreatment compositions there is no phosphate anion in certain embodiments；Then (c) is by the base Bottom is contacted with the coating composition comprising film-forming resin, to form the coating metallic substrates for showing corrosion resistance.Such In method, when the pretreatment baths are offed normal, except the step of de-iron includes or basic in some cases from the pretreatment baths On be made up of：(a) pH of the pretreatment baths is reduced at least 0.2；(b) phosphate anion is added to the pretreatment in (a) In bath；(c) oxidant is added in the pretreatment baths in (b)；(d) pH of the pretreatment baths in (c) is increased at least 0.2. As used herein, term " corrosion resistance " is referred to using test described in ASTM B117 (spray salt is tested), in metal The measurement of anticorrosive property in substrate.In the test, come sudden and violent according to ASTM D1654-92 with the coated substrate of knife scribing Expose exposed metallic substrates.Substrate through scribing is placed in test cabinet, it is wherein that aqueous saline solution is continuously spraying (mist) in substrate.The room is maintained at constant temperature.The coated substrate is exposed to the time as defined in salt mist environment, such as 250,500 or 1000 hours.After exposure, which is removed from test cabinet, and evaluates the corruption along scribing line Erosion.Corrosion is to be defined as corroding the total distance advanced along scribing line come what is measured by " scribing line creep ", is surveyed with millimeter Amount.When claiming substrate " showing corrosion resistance ", it indicate wherein substrate be according to the manufacturer's instructions, used as PCT 79111, available commercially from PPG Industries, in the case where the polyester powder paint coating of Inc., in salt mist environment, according to After ASTM B117 is tested 500 hours, the scribing line creep that ferrous metal substrate is shown is not more than 3 millimeters.

Illustrate that of the invention is the following examples, is not considered as limiting the invention to their details.Implement Whole parts and percentages are by weight, unless otherwise directed in example and the whole instruction.

Embodiment

Embodiment 1

In an experiment, it is about 1.8-2.4 containing fluorine zirconic acid and phosphoric acid that five clean steel plates, which are placed in pH, (the PO of the Zr and 10ppm of 90ppm₄ ^-3) aqueous solution in.After the ferrous iron concentration for establishing about 30ppm, by the plate from transparent It is removed in solution, and is divided into the part of 1 gallon (3.78 liters).

First gallon is further subdivided into the part of 700ml, the phosphoric acid of (75% weight) is added, thereto to generate one The bath foam of phosphate anion of the series with 10,25,50,75 and 100ppm.Same tie is repeated with the zirconium of 125,150 and 200ppm The phosphate radical of column is horizontal.

The pH that whole samples are bathed is adjusted to 5.0.By the ferrous iron containing 30ppm and different amounts of zirconium and phosphate anion Bath is static to place two days.Two days later, the appearance of each bath is recorded.The result being summarised in the following table 1 .0 is confirmed in the embodiment In, in the presence of the phosphate anion of 25-50ppm, the zirconium bath of total iron containing 30ppm will become white appearance from brown.It should Brown appearance indicates the formation of iron oxide or FeOOH (iron oxyhydroxide).

As a result matrix shows the PO of whole 10ppm₄ ^-3Bath forms the water of the iron rust dyeing of same degree and main For the sediment of brown；That is, unrelated with Zr level.The bath of secondary most light coloring is the PO of 25ppm₄ ^-3Bath also has thin The sediment of color.The PO of whole 50ppm₄ ^-3Near colorless is bathed, has and crystallizes linen precipitating almost inconspicuous in this way Object.The PO of 75 and 100ppm₄ ^-3Bath is entirely colourless, has white crystals sediment.The white depositions are ferric phosphates, can There can be a small amount of zirconium compounds.

It is at least 1 this example shows phosphate radical and ferric iron weight ratio：1, for example, at least 1.2：1, such as 1-1.8： 1, it is sufficient to prevented substantially when the bath is for handling ferrous metal substrate, in the pretreatment comprising IIIB and/or Group IVB metal Insoluble iron rust is formed in bath.

Table 1.0

Zirconium, ppm	Phosphate radical, ppm	Sediment appearance	Total iron, ppm	pH
					90	10	Brown	30	5.0
90	25	Brown	30	5.0
					90	50	White	30	5.0
90	75	White	30	5.0
					90	100	White	30	5.0
125	10	Brown	30	5.0
					125	25	Brown	30	5.0
125	50	White	30	5.0
					125	75	White	30	5.0
125	100	White	30	5.0
					150	10	Brown	30	5.0
150	25	Brown	30	5.0
					150	50	White	30	5.0
150	75	White	30	5.0
					150	100	White	30	5.0
200	10	Brown	30	5.0
					200	25	Brown	30	5.0
200	50	White	30	5.0
					200	75	White	30	5.0
200	100	White	30	5.0

Embodiment 2

Steel plate is cleaned using conventional base detergent, is rinsed twice with tap water, is containing 10-150ppm's It is handled in the bath of the phosphate radical of zirconium and 10-100ppm, and is then rinsed with tap water.By the steel plate P of the processing 590 cationic epoxy electrocoating paints or 79111 isocyanuric acid three-glycidyl esters of PCT-polyester powder coating japanning, Both available commercially from PPG Industries Inc.Corrosive nature is such as measurement of getting off：It, will be through zirconium according to ASTM B117 Processing and japanning plate is exposed to neutral salt spray and continues the time shown in table 2.0.In the test, cationic epoxy electricity is heavy Acceptable performance of the product coating under neutral salt spray exposure in 1000 hours is the 1/2 wide scribing line loss of 4.0-5.0mm. Acceptable performance of the TGIC- polyester powder paint under neutral salt spray exposure in 500 hours is the 1/2 wide scribing line of 2.0-3.0mm Loss.Following result is confirmed when phosphate anion is added in zirconium processing bath, can obtain acceptable corrosive nature. As shown in embodiment 1.0, under the phosphate anion of low concentration, processing bath becomes brown, and which show there is iron oxide Or FeOOH.

Table 2.0

Embodiment 3

It is prepared for a kind of preprocessing solution, the hexafluoro zirconate of incrementss is added thereto.It, will before coating cold-rolled steel sheet The pH of the bath is adjusted to 4.7.The plate of ACT Labs (Hillsdale, MI) will be come from first in alkaline cleaner (PPG Industries Chemkleen 611L, in 2% and 140-150 ℉) in spray cleaning, and enter pretreating zone before It rinses twice.Zirconium bath is sprayed onto the plate with 9psi and continues 60 seconds.Then they are rinsed with tap water, and finally spend from Sub- water rinses, and carries out infrared drying step later.

Panel sample is in the flat acquisition of 0,10,15,20,50 and 80ppm zirconium bath water.By each section of face, via XPS, (X is penetrated Photoelectron spectroscopic methodology) analysis, to measure the thickness degree of zirconium in coating.The depth of zirconium layer is determined as nanoscale, is distributed herein (profile) intersect back and drop to (cross back down to) 10% atomic percent level.The table of gained depth is opposite It draws in zirconium bath concentration, as shown in Figure 1.

It will be negative before the corrosion test according to ASTM B117 and D1654-92 using the panel from same series Ionic acrylic class electrocoating paint (as Powercron 395 available commercially from PPG Industries, Inc.) is applied with respective level It is coated on three panels.As the result is shown in Fig. 2.The result confirmation reached good corrosion protection degree, this with obtain most Small thickness (that is, obtained in bath with 20ppm zirconium) is consistent.

Embodiment 4

In practice, it is opaque brownish red by the bath of iron rust serious pollution, and is semitransparent orange solution before Appearance, this shows initial conversion at insoluble ferric complex.In an experiment, by 10 gallons containing 100ppm zirconium Low pH bath (~2.7) is to spraying steel plate several hours, until total iron content reaches 50ppm.Ferrous ion is about 40ppm.Though The right bath contains the soluble ferric ion of 10ppm, but it is transparent and colourless.By big sample part, The phosphate radical of cumulative level is added thereto, to determine after pH is increased to 5, prevents from bathing the level initially to change colour.For nothing For the control sample of phosphate radical, before bath will start discoloration, ferric level is increased into 24ppm.This experiment As the result is shown in table 3.0.

Table 3.0

With PO₄Horizontal increase, color change time-consuming is longer, and violent not as good as zero phosphate radical reference material.Separately Outside, after a whole night storage, pH drops to level shown in table, this shows oxidation and the completion of settling step.Work as use When more phosphate radical, which reduces smaller.After the phosphate radical of some levels, pH is kept constant, this shows to be more than trivalent The desired amount of excess of iron.In two days, sediment quality is it will be evident that as shown in table 3.0.There is no enough phosphoric acid in system In the case where root, sediment is formed as flocculated brown oxide, this leads to being decreased obviously for pH.In enough phosphoric acid In the case where root, sediment be it is white, have certain density iron is removed which promote before iron is carried to downstream.

Zirconium level is also checked for, to determine the influence of any excessive phosphate radical.Although Fig. 3 shows that some zirconiums exist It is consumed in system, but it is not substantive for losing.With phosphate radical soluble ferric complex is converted to it is insoluble Ferric phosphate can observe point of the equivalent addition phosphate radical into ferric iron by the stationary phase of pH.For the ferric iron of 24ppm For, this occurs under the phosphate radical of about 35-40ppm.

Therefore, in the above work bath, only 25-35ppm phosphate radical/24ppm ferric iron would be sufficient to inhibit to be formed it is reddish brown Color bath, and only consume seldom zirconium.The bath service life of the embodiment will be considerably longer than in competitive industry bath seen in typical case , industry bath is based on IIIB and/or Group IVB metal, but it does not include phosphate anion.The ratio between phosphate radical and ferric iron are 1：1-1.8：1, it is based on poidometer.Higher rate can start to consume excessive zirconium.

Embodiment 5

A kind of concentrate containing iron is such as acquisition of getting off：By clean steel plate hexafluoro zirconate deionized water solution Suspension two days in (it is free of phosphate radical).Final ferrous level is about 900ppm and ferric iron is 33ppm.The concentrate is right It is diluted afterwards with tap water, to provide the ferrous iron of about 20ppm and the ferric iron of 3ppm.Different amounts of phosphoric acid is added, is then added Whole ferrous irons is converted to ferric iron by enough hydrogen peroxide.Then the pH by each bath is adjusted to 4.7.Standing 1 day Later, the phosphate radical and zirconium of the bath are analyzed.As a result it is drawn in Fig. 4.It is apparent that the phosphate radical of about 30ppm will be enough to remove The ferric iron of 20ppm, while the zirconium of most of initial 65ppm is kept in the solution.

Embodiment 6

Embodiment 6 is carried out to confirm ferric iron (Fe⁺³) can be removed from pretreatment baths of offing normal.

A kind of liquid storage is prepared by the fluorine zirconic acid solution (45%) of 3 liters of tap water and 1.2g.The target of the liquid storage is 85ppm Zr.The ferric sulfate (50% solution) of 0.38ml is added into the liquid storage to obtain the target solution with 20ppm ferric ion. The pH of the liquid storage is 2.9.

The liquid storage is divided into bath A-D, each containing the liquid storage of 900ml.As described in more detail below, Hach meter is used for In the embodiment (and being used for embodiment 6 and 7), to measure the ferrous iron (Fe of different time points⁺²) and total concentration of iron.When expectation is in spy Ferric iron (Fe is obtained in fixed bath⁺³) concentration when, ferric iron concentration is obtained as the difference between total concentration of iron and ferrous iron concentration ?.In embodiment 6, A-D is bathed in measured any time point and does not all include any ferrous iron (Fe⁺²)。

Bath A acts as reference material, for the ferric iron (Fe with bath B, C and D (as described below to handle)⁺³) and total concentration of iron (ppm) it is compared.

It regard the Chemfil Buffer (a kind of alkaline solution, available commercially from PPG Industries, Inc.) of 0.1g as alkali Property source be added control bath A in, with obtain 3.4 pH.As shown in figure 5, bathing the ferric iron in A for the Therapy lasted phase of 72h (Fe⁺³) concentration (ppm) is about 18.6ppm.Visible rust sediment reluctantly is formed in bath A.These data confirm thats three Valence iron (Fe⁺³) it at pH range about 3.4 is quite stable.

The Chemfil Buffer of 0.5g is added in the liquid storage of bath B of 900ml, the pH of the bath is increased to 4.8, In its routine practice for being in the bath containing pretreatment compositions described herein.As shown in figure 5, in the pretreatment baths PH is increased to after 4.8, bathes the ferric iron (Fe in B⁺³) concentration is reduced to about 2ppm's from the initial concentration of about 21ppm in 2h Concentration.These are statistics indicate that most solubility ferric iron is converted to iron rust or di-iron trioxide, insoluble in the pre- place Manage composition.The 2h after increasing pH, the visible iron rust sediment in bath B.

The sodium dihydrogen phosphate of 0.09g (is provided as Zircobond Additive P, is obtained from PPG Industries, Inc., Euclid, OH (45 weight %)) it is added in the liquid storage of bath C of 900ml.Bathe the phosphorus that C includes 14ppm Acid group, and pH is 2.9, is stable during experiment in 72 hours.As shown in figure 5, ferric iron (the Fe in bath C⁺³) dense Degree in experiment drops to about 12ppm from about 18ppm in first 2 hours, and then within 72 hours Therapy lasted phases continuously by Step drops to the ultimate density of 7ppm.In first hour of experiment bath C in visible white sediment, and to test terminate When, shallow brown precipitation object is formd, this shows when the subnormal operation level of pH, and ferric removing is not gradually and not Completely.

The sodium dihydrogen phosphate (providing as Zircobond Additive P, (45 weight %)) of 0.09g is added Into the liquid storage of the bath D of 900ml.Bathe the phosphate radical that D includes 34ppm.As shown in figure 5, ferric iron (the Fe of bath D⁺³) concentration is 20ppm.The Chemfil Buffer of 0.5g is added in bath D, pH is increased to 4.75, and the bath is immediately turned into blushing 's.After settling crystal, bath sample is filtered by five um syringe filters, and check the total of the filtrate Iron.The ferric iron concentration bathed in D is 2ppm, and is (at the end of experiment) 1.9ppm after 2 hours.The bath is transparent, and With a small amount of white depositions.

The data confirm that of embodiment 6 addition phosphate radical eliminates most three into the pretreatment baths at lower ph Valence iron, and pH raising returns to after opereating specification, eliminates substantially all of ferric iron within a short period of time.These data Confirm that ferric iron can be removed from the pretreatment baths when the bath is offed normal.

Embodiment 7

With data confirm that described in embodiment 6 by the way that phosphate radical is added in pretreatment baths at a low ph shown in Fig. 5, Ferric iron is removed from the pretreatment baths.However, in practice, the pretreatment baths for having been used to processing substrate often include Ferrous iron must be translated into ferric iron, to remove from the pretreatment baths.It is shown in embodiment 7 and table 4 and described herein Data confirm that the removing of iron in ferrous state when oxidant improves initial into the pretreatment baths is added.

A kind of liquid storage is by the fluorine zirconic acid solution (45%) of 3 liters of tap water and 1.2g come what is prepared.The target of the liquid storage is The Zr of 85ppm.The FeSO47H2O of 0.32g is added, into the liquid storage to obtain the ferric ion with 20ppm (Fe⁺²) and 23ppm total iron target solution.The pH of the liquid storage is 3.1.

The liquid storage is divided into bath E-G, each containing the liquid storage of 900ml.E served as control object is bathed, it is (as follows with bath F and G It is described to handle) ferrous iron (Fe⁺²) and total concentration of iron (ppm) be compared.It is counted using Hach, during 44 hours of experiment It is interior, the ferrous iron and total concentration of iron of each bath are monitored at regular intervals.

Bathe E served as control object.The initial pH for bathing E is 3.1.A few drop Chemfil Buffer are added pH in the bath Increase to 3.5, as shown in table 4, keeps stablizing during the experiment.It is same as shown in table 4, bathe total concentration of iron (ppm) of E from first The 22.8ppm of beginning drops to the 22.1ppm at the end of experiment in 44 hours.Ferrous iron (Fe⁺²) concentration is initially 19.8ppm, and Drop to 15.7ppm at the end of experiment in 44 hours.The bath keeps transparent during the experiment, does not form red.These data Show that iron whole in the bath retains in the solution as ferrous, and only a small amount of ferrous iron is converted to ferric iron.These numbers It is confirmed that the conversion at low pH (that is, when pH is lower than operation pH), there is ferrous iron to ferric iron minimum.

The sodium dihydrogen phosphate (45% solution) of 0.093g is added in bath F and generates such solution, with 43ppm's Phosphate radical, and PO₄：The ratio between total iron is about 1.8：1.Then the Chemfil Buffer of 0.5g is added in the bath and is generated 4.7 pH.The pH of bath F is slightly decreased during the experiment, and is 4.38 at 44 hours.As shown in table 4, total iron in E is bathed Concentration drops to the 18.5ppm in 30min from initial 22.8ppm, and is 14.7ppm at the end of experiment in 44 hours. It is 19.8ppm when ferrous iron concentration is initial, drops to 17.2ppm in 30min, and be at the end of experiment in 44 hours 12.4ppm.Some white depositions are formd in bath during the experiment, this expression forms ferric phosphate.These statistics indicate that Phosphate radical is added, pH is then increased into 4.38-4.7, only eliminates some soluble irons as ferric phosphate, this is because It is relatively slow by only increasing pH for ferrous oxidation, and be limited to although being not intended to be limited to theory Balance relevant to pH.

As shown in table 4, bath G initial pH is 3.0, and total concentration of iron is 22.8ppm and ferrous iron concentration is 19.8ppm.Shortly It will be added before 0.32g hydrogen peroxide (3%wt solution), the sodium dihydrogen phosphate (45% solution) of 0.1g will be added in bath G.Adding When entering 15min after hydrogen peroxide, total concentration of iron drops to 10.2ppm, and ferrous iron concentration drops to 0.4ppm, and pH is 2.6.? Some white depositions are formed in bath, this shows that phosphoric acid iron complex is partially completed.Next, by being added 0.6g's Chemfil Buffer (starts 46 minutes afterwards) after increasing to the pH of the bath foam 4.7, and 15 minutes that is, testing, and eliminates Most iron, and total concentration of iron is 5ppm and ferrous iron concentration is 0.1ppm.At the end of experiment (that is, 44 small after starting When), the pH of bath is 4.6, and total concentration of iron is 0.24ppm and ferrous iron concentration is 0.02ppm.These data confirm thats addition phosphoric acid Root and hydrogen peroxide significantly improve into bath in the case where operating pH iron from the removing in bath.

Table 4.0

Embodiment 8

In this embodiment, by the way that the hexafluoro zirconate of 3.60g to be added to 3 liters of water, there is 240ppm zirconium to generate Solution carrys out manufacturing operation pretreatment baths.A certain amount of Chemfil Buffer is added, is enough the pH of solution being increased to 4.5. The FeSO47H2O of 0.31g is added to obtain 20ppm ferrous iron.Iron rust particle is formed in order to prevent, is added immediately about The hexafluoro zirconate of 14 drops, is reduced to 3.3 for pH.The bath is transparent.Total concentration of iron using Hach meter measurement is 23.2ppm It is 19.5ppm with ferrous iron.

It with the molar ratio with total iron to be precipitated is about 1 by phosphate radical：1 (or weight ratio is 1.8：1, by weight) It is added in the bath.The phosphate radical of the 41.5ppm of the phosphoric acid solution (75 weight %) from 0.175g, mistake are added into the bath Measure about 8-9ppm.After mixing 1min, it is then based on and ferrous molar ratio 1：1 (slightly excessive), is added the hydrogen peroxide of 1.27g Solution (3 weight %).The ferrous iron be less than 1min in be converted to ferric iron.

To precipitate whole ferric irons as ferric phosphate, by the way that Chemfil Buffer is added dropwise by the bath PH is slowly raised 4.75.If raising is too fast, it will form some insoluble iron oxide as iron rust, rather than phosphoric acid Iron.As pH is increased, white opacity is formed in bath, ultimately becomes flocculate, which settles completely in 10 minutes To generate transparent bath.The final solution includes the total iron of 0.2ppm, and does not have the ferrous iron that can be measured.Remaining phosphate radical is 8.5ppm, this is consistent with mass balance calculation.

Skilled artisans will appreciate that the embodiment above can be changed, it is general without departing from its wide invention It reads.It is therefore understood that the present invention is not limited to disclosed specific embodiments, and it is intended to covering and is wanted in additional right Change in spirit and scope of the invention defined by asking.

Claims (23)

1. a kind of method for removing de-iron from the pretreatment baths containing pretreatment compositions, which includes IIIB race And/or the metal of IV race, this method include：

(a) pH of the pretreatment baths is reduced at least 0.2；

(b) phosphate anion is added in the pretreatment baths in (a)；With

(c) pH of the pretreatment baths in (b) is increased at least 0.2.

2. the method for claim 1 wherein the pH of the pretreatment baths is reduced at least 1.0.

3. the method for claim 1 wherein the reduction includes that acid is added into the pretreatment baths.

4. method for claim 3, wherein the acid includes Group IVB fluorine metal acid, phosphoric acid, sulfuric acid, sulfamic acid, nitric acid and its mixes Close object.

5. method for claim 3, wherein the acid includes hexafluoro zirconate.

6. the method for claim 1 wherein the source of the phosphate anion includes alkali metal orthophosphate, ammonium orthophosphate and its is mixed Close object.

7. the method for claim 1 wherein the source of the phosphate anion includes sodium dihydrogen phosphate.

8. the method for claim 1 wherein the pretreatment baths in (c) there is no iron.

9. method of claim 1 further comprises that oxidant is added in the pretreatment baths in (b).

10. method for claim 9, wherein the oxidant includes peroxide compound.

11. method of claim 1 further comprises the pretreatment baths filtered in (c).

12. the method for claim 1 wherein this method is carried out in the absence of the product to be coated by the pretreatment compositions 's.

13. the method for claim 1 wherein the IIIB race and/or Group IVB metal include zirconium.

14. the method for claim 1 wherein the pretreatment compositions to further include phosphate anion.

15. a kind of method for removing de-iron from the pretreatment baths containing pretreatment compositions, which includes IIIB The metal of race and/or Group IVB, this method include：

(a) pH of the pretreatment compositions is fallen below 4.0 into the pretreatment baths by acid adding；

(b) phosphate anion is added in the pretreatment baths in (a)；With

(c) pH of the pretreatment baths in (b) is increased to 4-5.5.

16. the method for claim 15, wherein the acid includes hexafluoro zirconate.

17. the method for claim 15, wherein the source of the phosphate radical includes sodium dihydrogen phosphate.

18. the method for claim 15 further comprises in the pretreatment baths that oxidant is added in (b).

19. the method for claim 18, wherein the oxidant includes peroxide compound.

20. the method for claim 15 further comprises the pretreatment baths filtered in (c).

21. the method for claim 15, wherein after step (c), the pretreatment compositions in the pretreatment baths include The weight ratio of phosphate radical and ferric ion is 1：1 to 1.7：1 parts by weight.

22. the method for claim 15, wherein this method be in the absence of the product to be coated by the pretreatment compositions into Capable.

23. the method for claim 15, wherein the pretreatment compositions further include phosphate anion.