JPH10245685A - Pretreating liquid for surface conditioning before phosphate film chemical conversion treatment of metal and surface conditioning method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pretreating liquid and pretreatment method for accelerating chemical reaction and making phosphate film crystals finer in phosphate film chemical conversion treatment of metallic materials. SOLUTION: This pretreating liquid contains >=1 kinds selected from phosphate contg. at least one kind among bivalent or tervalent metals including particles having a grain size of <=5μm and alkaline metal salts or ammonium salts or their mixtures and is adjusted in its pH to 4 to 13. The concn. of the particles having the grain size of <=5μm may be confined to 0.001 to 30g/L. The bivalent or tervalent metals may be >=1 kinds selected from Zn, Fe, Mn, Ni, Co, Ca and Al. The alkaline metal salts or ammonium salts may be >=1 kinds selected from orthophosphate, metaphosphate, orthosilicate, metasilicate, carbonate, bicarbonate and borate. The pretreatment method may be executed by previously bringing the metallic surfaces into contact with the pretreating liquid.

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phosphate film chemical conversion treatment applied to the surface of a metal material such as iron and steel, galvanized steel sheet, and aluminum. The present invention also relates to a preconditioning solution for surface conditioning and a surface conditioning method used for miniaturizing phosphate film crystals.

[0002]

2. Description of the Related Art In recent years, in the case of phosphate treatment for automobiles, metal surfaces have been used to improve corrosion resistance after painting, and in the case of phosphate treatment for plastic working, in order to reduce friction during pressing or extend the life of the press die. It is required to form fine and dense phosphate film crystals. Therefore, in order to activate the metal surface to obtain fine and dense phosphate film crystals, and to create nuclei for phosphate film crystal deposition,
A surface conditioning step is employed before the phosphate film conversion treatment step. The following is an example of a general phosphate film conversion process performed to obtain fine and dense phosphate film crystals. (1) Degreasing (2) Rinse with water (multi-stage) (3) Surface conditioning (4) Chemical conversion treatment of phosphate film (5) Rinse with water (multi-stage) (6) Rinse with pure water

The surface conditioning step is used to make the phosphate film crystals fine and dense. Regarding the composition, for example, U.S. Pat.
Nos. 2349 and 2310239 disclose titanium, pyrophosphate ion, orthophosphate ion, sodium ion and the like as main components contained in the surface conditioner. The surface conditioning composition is called "Jernsted salt", and its aqueous solution contains titanium ions and titanium colloid. The titanium colloid is adsorbed on the metal surface by immersing the degreased and washed metal in an aqueous solution of the surface conditioning composition or by spraying the metal with a surface conditioning pretreatment liquid. The adsorbed titanium colloid serves as a nucleus for depositing phosphate film crystals in the subsequent phosphate film conversion treatment step, thereby facilitating the chemical conversion reaction and making the phosphate film crystals finer and denser. All surface conditioning compositions currently used industrially are based on Jernstead salts. However, when a titanium colloid obtained from the Jernsted salt is used in the surface conditioning step, there are various problems.

A first problem is that the surface treatment pretreatment liquid deteriorates with time. When a conventional surface conditioning composition is used, immediately after the composition is made into an aqueous solution, a remarkable effect is achieved with respect to miniaturization and densification of phosphate film crystals. However, when several days elapse after being made into an aqueous solution, the effect is lost irrespective of the use of the surface conditioning pretreatment liquid during the elapsed days due to the aggregation of the titanium colloid, and the obtained phosphate film crystal Becomes coarse. Therefore, JP-A-63-76883 discloses that the average particle size of titanium colloid in the pretreatment liquid for surface adjustment is measured, and the pretreatment liquid for surface adjustment is continuously applied so that the average particle diameter is smaller than a certain value. There has been proposed a method for maintaining and controlling the surface conditioning effect by discarding the surface and further replenishing the discarded surface conditioning composition. However, although this method enabled quantitative management of the factors for the effect of the surface conditioning pretreatment liquid, it was necessary to discard the surface conditioning pretreatment liquid in order to maintain the effect. In addition, in order to maintain the effect of the surface conditioning pretreatment liquid in this method at the same level as when the aqueous solution is initially used, a large amount of the surface conditioning pretreatment liquid needs to be discarded. Therefore, there is also a problem of the wastewater treatment capacity of a factory actually used, and the effect is maintained by using both continuous disposal of the pretreatment liquid for surface conditioning and renewal of the entire amount.

[0005] The second problem is that the effect and life are greatly affected by the quality of the water used for bathing the surface conditioning pretreatment liquid. In general, industrial water is used for bathing the surface treatment pretreatment liquid. However, as is well known, industrial water contains cation components such as calcium and magnesium which cause the total hardness, and the content varies depending on the industrial water source used. Here, it is known that the titanium colloid, which is the main component of the conventional pretreatment liquid for surface conditioning, has an anionic charge in an aqueous solution and is dispersed without settling due to its electric repulsion. ing.

Accordingly, when a large amount of calcium or magnesium as a cation component is present in industrial water, the titanium colloid is electrically neutralized by the cation component, loses repulsive force and causes coagulation and sedimentation, thereby losing its effect. Therefore, a method has been proposed in which a condensed phosphate such as pyrophosphate is added to a preconditioning solution for surface conditioning in order to block the cation component and maintain the stability of the titanium colloid. However, when a large amount of condensed phosphate is added to the surface treatment pretreatment liquid, the condensed phosphoric acid reacts with the steel sheet surface to form an inactive film, so that formation of a phosphate film in the subsequent phosphate film chemical conversion treatment step results in defective formation. Have the adverse effect of Further, in an area where the content of magnesium and calcium is extremely high, it is necessary to perform bathing and water supply of the pretreatment liquid for surface adjustment using pure water, which is extremely disadvantageous in terms of economy.

As a third problem, there are restrictions on temperature and pH under use conditions. Specifically, the temperature is 35 ° C.
As described above, when the pH is outside the range of 8.0 to 9.5, the titanium colloid aggregates and the surface adjusting effect cannot be exhibited. Therefore, when using the conventional surface conditioning composition, it is necessary to use a predetermined temperature, pH range, and,
It has not been possible to add the surface conditioning composition to a degreasing agent or the like to exert the effects of cleaning and activating the metal surface in one liquid over a long period of time.

A fourth problem is a limit value of miniaturization of phosphate film crystals obtained by the effect of the pretreatment liquid for surface conditioning. The surface conditioning effect can be obtained by the titanium colloid being adsorbed on the metal surface to form nuclei when depositing phosphate film crystals. Therefore, as the number of titanium colloids adsorbed on the metal surface in the surface conditioning step increases, finer and more dense phosphate film crystals can be obtained. For that purpose, it is easily conceivable to increase the number of titanium colloids in the pretreatment liquid for surface conditioning, that is, to increase the concentration of titanium colloids. However, when the concentration is increased, the frequency of collision between titanium colloids in the surface treatment pretreatment liquid increases, and the collision causes coagulation and precipitation of titanium colloid.
The upper limit of the concentration of titanium colloid currently used is 100 ppm or less as titanium in the pretreatment liquid for surface conditioning, and it is a conventional technique to increase the concentration of titanium colloid to further refine the phosphate film crystal. Was not possible.

Therefore, in JP-A-56-156778 and JP-A-57-23066, an insoluble phosphate of a divalent or trivalent metal is added to the surface of a steel strip as a surface conditioner other than the Jernsted salt. A surface conditioning method for spraying a suspension containing the same under pressure is disclosed. However, this surface conditioning method is only effective when the suspension is sprayed under pressure on the material to be treated, so it is used for surface conditioning in phosphate film chemical conversion treatment, which is usually performed by dipping and spraying. could not.

Japanese Patent Publication No. 40-1095 discloses a surface conditioning method in which a galvanized steel sheet is immersed in a high-concentration divalent or trivalent metal insoluble phosphate suspension. However, the examples shown by this method are limited to galvanized steel sheets, and in order to obtain a surface conditioning effect, it was necessary to use a high-concentration insoluble phosphate suspension of at least 30 g / L or more. .

[0011] Accordingly, although various problems of the Jernsted salt have been proposed, a new technology which can replace it has not yet been proposed.

[0012]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, and accelerates and shortens the chemical conversion reaction and reduces the size of the obtained phosphate film crystal in the phosphate film conversion treatment. It is an object of the present invention to provide a novel surface treatment pretreatment liquid having excellent stability over time and a method for conditioning the surface, which are used to achieve the following.

[0013]

Means for Solving the Problems The present inventors diligently study means for solving the above-mentioned problems, solve the problems in the conventional method, and further improve the quality of the phosphate film crystal. A novel pretreatment liquid for surface preparation and a method for surface preparation, which can perform the above, have been completed. That is, the pretreatment liquid for surface conditioning before the metal phosphate film chemical conversion treatment of the present invention is a phosphate containing at least one divalent or trivalent metal containing particles having a particle size of 5 μm or less. It is characterized by containing one or more kinds, an alkali metal salt or an ammonium salt or a mixture thereof, and adjusting the pH to 4 to 13.

The concentration of the particles having a particle size of 5 μm or less is 0.001.
-30 g / L, and the divalent or trivalent metal is Z
It is preferably at least one selected from n, Fe, Mn, Ni, Co, Ca, and Al. The alkali metal salt or ammonium salt is at least one salt selected from orthophosphate, metaphosphate, orthosilicate, metasilicate, carbonate, bicarbonate, and borate. And its concentration is 0.5 to 20 g
/ L is preferable. Further, at least one selected from the group consisting of anionic charged and dispersed oxide fine particles, an anionic water-soluble organic polymer, a nonionic water-soluble organic polymer, an anionic surfactant, and a nonionic surfactant. Preferably, it contains a species. It is preferable that the anionic charged and dispersed oxide fine particles have an average particle diameter of 0.5 μm or less and a concentration of 0.001 to 5 g / L. Further, the anionic charged and dispersed oxide fine particles are composed of Si, B, Ti, Zr, Al, S
It is desirably at least one selected from b, Mg, Se, Zn, Sn, Fe, Mo, and V oxide.

The surface conditioning method of the present invention before the metal phosphate coating conversion treatment is characterized in that the metal surface is brought into contact with the surface conditioning pretreatment liquid.

Furthermore, the pretreatment liquid for surface conditioning according to the present invention is very excellent in stability in a high pH range and stability at high temperature as compared with conventional products, and therefore, a nonionic surfactant is used. Alternatively, by adding an anionic surfactant or a mixture thereof and a builder, it can also be used in a degreasing and surface treatment method that combines cleaning and activation of the metal surface.

[0017]

The function of each component in the present invention will be described in detail.

One or more phosphates containing at least one divalent or trivalent metal (hereinafter simply referred to as "divalent or trivalent metal phosphate") are essential components in the present invention. It is. As described above, an object of the present invention is to provide a preconditioning solution for surface conditioning which is used for activating a metal surface before phosphating and forming nuclei for depositing a phosphate film crystal. The present inventors have reported that a phosphate of a divalent or trivalent metal having a specific concentration and a particle size is adsorbed on the surface of an object to be treated in an aqueous solution containing a specific additive, and then the phosphate film crystal is formed. It was invented to increase the rate of the phosphate conversion treatment by forming a nucleus during precipitation.

Further, since the phosphate of the divalent or trivalent metal is a component similar to the phosphate chemical conversion treatment bath and the phosphate chemical conversion treatment film, it is carried into the phosphate chemical conversion treatment bath. They also have the advantage that they do not adversely affect the chemical conversion treatment bath and that they do not adversely affect the performance of the phosphate conversion coating even if they are taken into the phosphate coating as nuclei. Examples of the divalent or trivalent metal phosphate used in the present invention include the following examples. Phosphates of divalent or trivalent metals Zn ₃ (PO ₄ ) ₂ , Zn ₂ Fe (PO ₄ ) ₂ , Zn ₂ Ni (PO ₄ ) ₂ , Ni ₃ (PO ₄ ) ₂ , Zn ₂ Mn
(PO ₄ ) ₂ , Mn ₃ (PO ₄ ) ₂ , Mn ₂ Fe (PO ₄ ) ₂ , Ca ₃ (PO ₄ ) ₂ , Zn ₂ Ca (P
O ₄ ) ₂ , FePO ₄ , AlPO _4, CoPO ₄ , Co ₃ (PO ₄ ) ₂

It is known that the particle size of the phosphate film crystal formed on the metal surface becomes finer as the number of crystals per unit area precipitated in the early stage of the reaction increases. this is,
Since the growth of the phosphate film crystals is completed when the adjacent crystals come in contact with each other and cover the metal surface, if the number of crystals deposited in the initial stage of the reaction is large, the distance between the adjacent crystals will be small and the time will be short. This is because fine crystals cover the metal surface. Therefore, in order to precipitate fine phosphate crystals in a short time, it is effective to add many crystal nuclei before the phosphate conversion treatment. It is needless to say that a smaller value is advantageous. Further, in order to stably disperse the insoluble substance in the aqueous solution, the particle diameter of the divalent or trivalent metal phosphate used in the present invention is desirably 5 μm or less. However, even if a divalent or trivalent metal phosphate having a particle diameter of 5 μm or more is present in the surface treatment pretreatment liquid of the present invention, it does not affect the effects of the present invention at all. The effect is exhibited only when the concentration of the fine particles of 5 μm or less in the aqueous solution for adjusting the surface reaches a certain concentration.

In the present invention, by controlling the particle size of the phosphate of the divalent or trivalent metal, it is possible to control the particle size of the phosphate film crystals obtained. By using a finely ground phosphate of a divalent or trivalent metal, ultrafine phosphate crystals can be precipitated for the above-described reason.

The reaction rate of the phosphate conversion treatment reaction is determined by the amount of active phosphate ions that can reach the surface of the object to be treated per unit time, and is described by Fick's law.

[0023]

(Equation 1)

[0024] Here, the reaction rate of d _n is large enough phosphate chemical conversion treatment reaction is large. Therefore, in order to increase the reaction rate of the phosphate conversion treatment, it is necessary to reduce the denominator on the right side of the equation (1) or increase the numerator.
However, the denominator is the thickness of the adhesion layer, and in order to reduce the thickness of the adhesion layer, it is necessary to rely on physical effects such as increasing the stirring in the phosphate conversion treatment step. Also, the diffusion coefficient does not change significantly because it is determined by the bath composition of the phosphate conversion treatment bath. Therefore, there is no other way to increase the molecule, that is, increase the reaction rate, except to increase the amount of active phosphate ions in the phosphate conversion treatment bath.

The present inventors have focused on the initial state of the reaction in the Fick's law described above and made an investigation. The start of the reaction, that is, C _B are 0 at the stage of metal is in contact with the phosphating solution, the first phosphate coating crystals precipitated occur upon reaching C _B to a concentration capable of precipitated phosphate coating crystals . Thus small time until d _n is the more C _B larger reaches the concentration is believed that the initial reaction is likely to occur as the C _A is larger (1) below. However, C _A i.e., increasing needlessly the phosphate ion concentration in the phosphate chemical treatment bath, expedient to cause the coarsening of precipitates and the resulting phosphate conversion coating surplus sludge by hydrolysis Absent. So it's possible the same effect as increasing the surface conditioning treatment by phosphate chemical conversion treatment reaction initial C _B invented a technique obtained. That is, the phosphate of the divalent or trivalent metal in the pretreatment liquid for surface conditioning not only serves as a nucleus for crystal precipitation but also has a low pH in the phosphate conversion treatment liquid. C _{B on the} metal surface in the early stage of dissolution and reaction
It has the function of increasing Accordingly, the closer the target component of the phosphate conversion coating and the component of the divalent or trivalent metal phosphate in the aqueous surface conditioner solution are, the greater the effect is.

C _B in the initial phosphate conversion treatment
In order to increase the concentration, the phosphate concentration of the divalent or trivalent metal is preferably 0.001 to 30 g / L. This is because the phosphate concentration of the divalent or trivalent metal is 0.0
01G / small and not enhanced is C _B to a concentration capable of promoting the phosphate chemical conversion treatment reaction for divalent or trivalent phosphate of the metal is hardly adsorbed on the metal surface than L, also crystals The reaction is not promoted because the number of divalent or trivalent metal phosphates serving as nuclei is also small. Divalent or three
Even if the phosphate concentration of the monovalent metal is greater than 30 g / L, the effect of further promoting the phosphate conversion treatment reaction cannot be obtained, and it is only economically disadvantageous.

Next, as an essential component of the present invention, an alkali metal salt or an ammonium salt or a mixture thereof (hereinafter, simply referred to as "alkali metal salt or ammonium salt") is exemplified. As shown in the prior art, a method of adjusting the surface by spraying an insoluble phosphate of a divalent or trivalent metal under pressure has been attempted in the past. However, in the past methods, it was necessary to spray a divalent or trivalent metal insoluble phosphate under pressure. The reason for spraying under pressure is that in order to exert a surface conditioning effect, it is necessary to cause an insoluble phosphate to strike the metal surface and react, or to scratch the metal surface as in shot peening. In addition, in order to obtain a surface conditioning effect by immersion treatment, in the conventional method, it was necessary to extremely increase the concentration of the insoluble phosphate of a divalent or trivalent metal.

The present inventors have found that when an alkali metal salt or an ammonium salt is present, the concentration of a phosphate of a divalent or trivalent metal is low and the immersion treatment in which a physical force is not applied to the metal surface. They invented that the surface conditioning effect was also exhibited. Therefore, in the present invention, it is only necessary to contact the object to be treated with the surface treatment pretreatment liquid,
The reaction mechanism is completely different from the prior art. For this purpose, an alkali metal salt or an ammonium salt is required as an essential component.

As the alkali metal salt or ammonium salt, orthophosphate, metaphosphate, orthosilicate,
There is no particular limitation as long as it is in the form of at least one salt selected from the group consisting of metasilicate, carbonate, bicarbonate, and borate. Further, there is no problem even if two or more of the above alkali metal salts or ammonium salts are used in combination.

The concentration of the alkali metal salt or ammonium salt is desirably 0.5 to 20 g / L. When the concentration is less than 0.5 g / L, the surface conditioning effect is not exhibited only by bringing the object to be treated into contact with the pretreatment liquid for surface conditioning.
Above g / L, no further effect can be expected and it is only economically disadvantageous.

The pretreatment liquid for surface conditioning in the present invention has a pH of
It is necessary to adjust to a range of 4 to 13. If the pH is lower than 4, the metal is corroded in the surface treatment pretreatment liquid to form an oxide film or the like, which may cause a poor phosphate conversion treatment. If the pH exceeds 13, the phosphate conversion aqueous solution is acidic, so that when the surface conditioning pretreatment liquid is brought into the phosphate conversion treatment step, the phosphate conversion treatment bath is neutralized. This is because there is a risk of breaking the balance of the bath.

In the present invention, it is preferable to add anionic charged and dispersed oxide fine particles. The function of the oxide fine particles will be described below.

First, the oxide fine particles are adsorbed on the metal surface and become nuclei in phosphate crystal precipitation, that is, become microcathodes and serve as starting points for a phosphate conversion treatment reaction.

Second, the dispersion stability of the phosphate of a divalent or trivalent metal in the pretreatment liquid for surface conditioning can be improved. Oxide fine particles are adsorbed on a divalent or trivalent metal phosphate dispersed in a preconditioning solution for surface conditioning or
By preventing collision of the phosphates of the divalent or trivalent metal, coagulation and precipitation of the phosphate of the divalent or trivalent metal are prevented, and the stability is improved. For this purpose, the particle size of the oxide fine particles must be smaller than the particle size of the divalent or trivalent metal phosphate.

Specifically, the thickness is preferably 0.5 μm or less. The oxide fine particles used in the present invention are not limited to the metal of the oxide fine particles as long as they satisfy the particle size and the anionic property. Further, the surface charge may be changed to an anionic by subjecting the cationic oxide fine particles to a surface treatment. An example of the oxide fine particles used in the present invention is as follows. Oxide fine particles SiO ₂ , B ₂ O ₃ , TiO ₂ , ZrO ₂ , Al ₂ O ₃ , Sb ₂ O ₅ , Mg
O, SeO ₂ , ZnO, SnO ₂ , Fe ₂ O ₃ MoO ₃ , Mo ₂ O ₅ , V ₂ O _{5 In} the present invention, the divalent or trivalent metal phosphate of the pretreatment liquid for surface conditioning is used. The effect of improving the dispersion stability can be similarly obtained by using an anionic water-soluble organic polymer, a nonionic water-soluble organic polymer, an anionic surfactant, a nonionic surfactant, or the like.

The concentration of the oxide fine particles is 0.001 to 5 g /
L is desirable. When the concentration of the oxide fine particles is 0.0
If it is less than 01 g / L, the dispersion stability of the divalent or trivalent metal phosphate in the surface treatment pretreatment liquid, which is the use of the oxide fine particles in the present invention, cannot be increased. Further, even if added in an amount of 5 g / L or more, the effect of enhancing the dispersion stability of the divalent or trivalent metal phosphate is not increased further, so that the upper limit of the concentration is sufficient at 5 g / L.

Unlike the conventional method, the pretreatment liquid for surface conditioning in the present invention can maintain its effect in any use environment. That is, it has the following advantages as compared with the conventional method. (1) High stability over time. (2) Even if hardness components such as Ca and Mg are mixed, the effect does not decrease. (3) Use at high temperatures is possible. (4) Various alkali metal salts can be added. (5) High stability in a wide pH range. (6) The particle size of the resulting phosphate crystals can be controlled.

Therefore, it can be used as a degreasing and surface conditioner which could not maintain a stable quality in the conventional method. At that time, known inorganic alkali builders, organic builders, surfactants and the like may be added in order to enhance the detergency in the degreasing and surface conditioning step. In addition, a known chelating agent, condensed phosphate, or the like may be added to cancel the influence of a cation component or the like brought into the surface treatment pretreatment liquid regardless of degreasing and surface conditioning.

The surface conditioning method of the present invention only requires contact of the surface conditioning pretreatment liquid with the metal surface, and there is no limitation on the contact time, the temperature of the surface conditioning pretreatment liquid, and the like. Further, the surface conditioning method of the present invention can be applied to any metal material which is subjected to a phosphate treatment such as steel, galvanized steel sheet, aluminum or aluminum alloy.

[0040]

EXAMPLES Next, the effects of applying the surface treatment pretreatment liquid of the present invention will be described in detail with reference to examples and comparative examples. However, as an example of the phosphate treatment, zinc phosphate treatment for automobiles is shown, and the use of the surface conditioning pretreatment liquid in the present invention is not limited.

(Test plate) The abbreviations and details of the test plates used in the examples and comparative examples are shown below. SPC (cold rolled steel sheet: JIS-G-3141) EG (double-sided electrogalvanized steel sheet: plating weight 20g /
m2) GA (double-sided alloyed hot-dip galvanized steel sheet: coating weight 4)
5g / m2) Zn-Ni (double-sided galvanized nickel-plated steel sheet: plating weight 20g / m2) Al (aluminum sheet: J
IS-5052)

(Alkaline Degreasing Solution) Fine Cleaner L4460 (registered trademark: manufactured by Nippon Parkerizing Co., Ltd.) was diluted to 2% with tap water and used in both Examples and Comparative Examples.

(Surface Conditioning Agent) Table 1 shows the composition of the surface conditioning pretreatment solution used in the examples, and Table 2 shows the composition of the surface conditioning pretreatment solution used in the comparative example. The aging test was performed after the surface treatment pretreatment liquid was prepared and left at room temperature for one week.

Example 1 A reagent obtained by grinding a Zn ₃ (PO ₄ ) ₂ .4H ₂ O reagent with a ball mill using zirconia beads for 10 minutes was used as a phosphate of a divalent or trivalent metal. The suspension of the divalent or trivalent metal phosphate was filtered through a 5 μm paper filter, and the average particle size of the filtrate was measured with a submicron particle analyzer (Coulter N4: Coulter). It was 0.31 μm. Further, the concentration of the phosphate of a divalent or trivalent metal in the filtrate was adjusted to 2 g / L. After adding a sodium tertiary phosphate reagent as an alkali metal salt to the suspension whose concentration was adjusted, the pH was adjusted to a predetermined value as a pretreatment liquid for surface adjustment shown in Table 1.

Example 2 A reagent obtained by grinding a Zn ₃ (PO ₄ ) ₂ .4H ₂ O reagent with a ball mill using zirconia beads for 10 minutes was used as a phosphate of a divalent or trivalent metal. The suspension of the divalent or trivalent metal phosphate was filtered through a 5 μm paper filter, and the average particle size of the filtrate was measured with a submicron particle analyzer (Coulter N4: Coulter). It was 0.31 μm. Further, the concentration of the phosphate of a divalent or trivalent metal in the filtrate was adjusted to 2 g / L. SiO ₂ (AEROSIL # 300: Nippon Aerosil Co., Ltd.)
After addition of a sodium tertiary phosphate reagent as an alkali metal salt, the pH was adjusted to a predetermined value as a pretreatment liquid for surface adjustment shown in Table 1.

Example 3 A reagent obtained by grinding a Zn ₃ (PO ₄ ) ₂ .4H ₂ O reagent in a mortar for 1 minute was used as a phosphate of a divalent or trivalent metal. After making the phosphate of the divalent or trivalent metal a suspension,
m, and the average particle size of the filtrate was measured with a submicron particle analyzer (Coulter N4 type: Coulter). As a result, it was 4.2 μm. Furthermore, the concentration of the phosphate of the divalent or trivalent metal in the filtrate is 2%.
g / L. After adding SiO ₂ (AEROSIL # 300: manufactured by Nippon Aerosil Co., Ltd.) as fine oxide particles to the suspension whose concentration has been adjusted, and a sodium tertiary phosphate reagent as an alkali metal salt, the pH is adjusted to a predetermined value. It was adjusted as a pretreatment liquid for surface adjustment shown in Table 1.

Example 4 A reagent obtained by pulverizing a Zn ₃ (PO ₄ ) ₂ .4H ₂ O reagent with a ball mill using zirconia beads for 1 hour was used as a phosphate of a divalent or trivalent metal. The suspension of the divalent or trivalent metal phosphate was filtered through a 5 μm paper filter, and the average particle size of the filtrate was measured with a submicron particle analyzer (Coulter N4: Coulter). It was 0.09 μm. Further, the concentration of the phosphate of a divalent or trivalent metal in the filtrate was adjusted to 2 g / L. SiO ₂ (AEROSIL # 300: Nippon Aerosil Co., Ltd.)
After addition of a sodium tertiary phosphate reagent as an alkali metal salt, the pH was adjusted to a predetermined value as a pretreatment liquid for surface adjustment shown in Table 1.

Example 5 1 L of 0.5 mol / L iron (II) sulfate solution heated to 50 ° C.
Then, 100 mL of a 1 mol / L zinc sulfate solution and 100 mL of a 1 mol / L sodium hydrogen phosphate solution were alternately added to generate a precipitate. After the aqueous solution containing the precipitate was heated at 90 ° C. for 1 hour to mature the precipitated particles, the inclined washing was repeated 10 times. The precipitate obtained by filtration was dried and analyzed by X-ray diffraction. As a result, the precipitate was partially filtered with phosphophyllite [Zn ₂ Fe (PO ₄ ) ₂ .4H ₂ O] containing ferric phosphate. there were. The phosphophyllite was pulverized for 10 minutes by a ball mill using zirconia beads and used as a phosphate of a divalent or trivalent metal. The suspension of the divalent or trivalent metal phosphate was filtered through a 5 μm paper filter, and the average particle size of the filtrate was measured with a submicron particle analyzer (Coulter N4: Coulter). 0.29 μm. Further, the concentration of the phosphate of a divalent or trivalent metal in the filtrate was adjusted to 2 g / L. SiO ₂ (AEROSIL # 300: Nippon Aerosil Co., Ltd.)
After addition of a sodium tertiary phosphate reagent as an alkali metal salt, the pH was adjusted to a predetermined value as a pretreatment liquid for surface adjustment shown in Table 1.

Example 6 1 L of a 0.1 mol / L manganese nitrate solution heated to 50 ° C.
200 mL of a 1 mol / L zinc nitrate solution is added to
Was added to generate a precipitate. After the aqueous solution containing the precipitate was heated at 90 ° C. for 1 hour to mature the precipitated particles, the inclined washing was repeated 10 times. A part of the precipitate obtained by filtration was dissolved in hydrochloric acid, and the components were analyzed using an atomic absorption spectrometer. As a result, the precipitate was [Zn _X Mn _Y (PO ₄ ) ₂ ]. The above [Zn _X Mn _Y (PO ₄ ) ₂ ] was pulverized for 10 minutes by a ball mill using zirconia beads, and used as a divalent or trivalent metal phosphate. The suspension of the divalent or trivalent metal phosphate was filtered through a 5 μm paper filter, and the average particle size of the filtrate was measured with a submicron particle analyzer (Coulter N4: Coulter). 0.32μm
Met. Further, the concentration of the phosphate of a divalent or trivalent metal in the filtrate was adjusted to 2 g / L. SiO ₂ as the oxide fine particles suspension wherein is density adjustment (AEROSIL #
300: manufactured by Nippon Aerosil Co., Ltd.) and a tertiary sodium phosphate reagent as an alkali metal salt, and the pH was adjusted to a predetermined value as a surface treatment pretreatment liquid shown in Table 1.

Example 7 0.1 mol / L calcium nitrate solution 1 heated to 50 ° C.
200 mL of a 1 mol / L zinc nitrate solution is added to
A 200 L / L solution of sodium hydrogen phosphate was added to form a precipitate. After the aqueous solution containing the precipitate was heated at 90 ° C. for 1 hour to mature the precipitated particles, the inclined washing was repeated 10 times. The precipitate obtained by filtration was dried and analyzed by X-ray diffraction. As a result, it was found that the precipitate was chortite [Zn ₂ Ca (PO ₄ ) _2.
It was H ₂ O]. The above-mentioned choltite was pulverized for 10 minutes by a ball mill using zirconia beads and used as a phosphate of a divalent or trivalent metal. The suspension of the divalent or trivalent metal phosphate was filtered through a 5 μm paper filter, and the average particle size of the filtrate was measured with a submicron particle analyzer (Coulter N4: Coulter). It was 0.30 μm. Further, the concentration of the phosphate of the divalent or trivalent metal in the filtrate is 2 g /
L was adjusted. After adding SiO ₂ (AEROSIL # 300: manufactured by Nippon Aerosil Co., Ltd.) as fine oxide particles to the suspension whose concentration has been adjusted, and a sodium tertiary phosphate reagent as an alkali metal salt, the pH is adjusted to a predetermined value. Table 1
Was prepared as a pretreatment liquid for surface adjustment shown in Table 1.

Example 8 A Zn ₃ (PO ₄ ) ₂ .4H ₂ O reagent was pulverized for 10 minutes by a ball mill using zirconia beads and used as a phosphate of a divalent or trivalent metal. The suspension of the divalent or trivalent metal phosphate was filtered through a 5 μm paper filter, and the average particle size of the filtrate was measured with a submicron particle analyzer (Coulter N4: Coulter). It was 0.31 μm. Further, the concentration of the phosphate of the divalent or trivalent metal in the filtrate was adjusted to be 0.02 g / L. ZrO ₂ sol as oxide fine particles (NZS-30B: Nissan Chemical Industries, Ltd.)
After addition of a sodium tertiary phosphate reagent as an alkali metal salt, the pH was adjusted to a predetermined value as a pretreatment liquid for surface adjustment shown in Table 1.

Example 9 A reagent obtained by grinding a Zn ₃ (PO ₄ ) ₂ .4H ₂ O reagent with a ball mill using zirconia beads for 10 minutes was used as a phosphate of a divalent or trivalent metal. The suspension of the divalent or trivalent metal phosphate was filtered through a 5 μm paper filter, and the average particle size of the filtrate was measured with a submicron particle analyzer (Coulter N4: Coulter). It was 0.31 μm. Further, the concentration of the phosphate of a divalent or trivalent metal in the filtrate was adjusted to 30 g / L. Sb ₂ O ₅ sol (A-1530: manufactured by Nissan Chemical Industries, Ltd.) as oxide fine particles in the concentration-adjusted suspension,
Further, after adding a sodium tertiary phosphate reagent as an alkali metal salt, the pH was adjusted to a predetermined value as a pretreatment liquid for surface adjustment shown in Table 1.

Example 10 A Zn ₃ (PO ₄ ) ₂ .4H ₂ O reagent was pulverized for 10 minutes by a ball mill using zirconia beads and used as a phosphate of a divalent or trivalent metal. The suspension of the divalent or trivalent metal phosphate was filtered through a 5 μm paper filter, and the average particle size of the filtrate was measured with a submicron particle analyzer (Coulter N4: Coulter). It was 0.31 μm. Further, the concentration of the phosphate of a divalent or trivalent metal in the filtrate was adjusted to 2 g / L. SiO ₂ (AEROSIL # 300: Nippon Aerosil Co., Ltd.)
After addition of a sodium metasilicate reagent as an alkali metal salt, the pH was adjusted to a predetermined value as a pretreatment liquid for surface adjustment shown in Table 1.

Example 11 A reagent obtained by grinding a Zn ₃ (PO ₄ ) ₂ .4H ₂ O reagent with a ball mill using zirconia beads for 10 minutes was used as a phosphate of a divalent or trivalent metal. The suspension of the divalent or trivalent metal phosphate was filtered through a 5 μm paper filter, and the average particle size of the filtrate was measured with a submicron particle analyzer (Coulter N4: Coulter). It was 0.31 μm. Further, the concentration of the phosphate of a divalent or trivalent metal in the filtrate was adjusted to 2 g / L. SiO ₂ (AEROSIL # 300: Nippon Aerosil Co., Ltd.)
After addition of a sodium sesquicarbonate reagent as an alkali metal salt, the pH was adjusted to a predetermined value as a pretreatment liquid for surface adjustment shown in Table 1.

Example 12 A reagent obtained by grinding a Zn ₃ (PO ₄ ) ₂ .4H ₂ O reagent with a ball mill using zirconia beads for 10 minutes was used as a phosphate of a divalent or trivalent metal. The suspension of the divalent or trivalent metal phosphate was filtered through a 5 μm paper filter, and the average particle size of the filtrate was measured with a submicron particle analyzer (Coulter N4: Coulter). It was 0.31 μm. Further, the concentration of the phosphate of a divalent or trivalent metal in the filtrate was adjusted to 2 g / L. SiO ₂ (AEROSIL # 300: Nippon Aerosil Co., Ltd.)
After addition of a sodium tertiary phosphate reagent as an alkali metal salt, the pH was adjusted to a predetermined value as a pretreatment liquid for surface adjustment shown in Table 1.

Example 13 A Zn ₃ (PO ₄ ) ₂ .4H ₂ O reagent was pulverized by a ball mill using zirconia beads for 10 minutes and used as a phosphate of a divalent or trivalent metal. The suspension of the divalent or trivalent metal phosphate was filtered through a 5 μm paper filter, and the average particle size of the filtrate was measured with a submicron particle analyzer (Coulter N4: Coulter). It was 0.31 μm. Further, the concentration of the phosphate of a divalent or trivalent metal in the filtrate was adjusted to 2 g / L. SiO ₂ (AEROSIL # 300: Nippon Aerosil Co., Ltd.)
After addition of a sodium tertiary phosphate reagent as an alkali metal salt, the pH was adjusted to a predetermined value as a pretreatment liquid for surface adjustment shown in Table 1.

Example 14 Using the same processing solution as in Example 2, a pretreatment for surface conditioning was performed at a processing temperature of 40 ° C.

Example 15 A surfactant (polyoxyethylene nonylphenol ether: 11 mol of EO) 2 g / L was added to the treatment liquid of Example 14, and the test piece as oiled at a treatment temperature of 40 ° C. without degreasing was performed. Was subjected to a degreasing and surface conditioning treatment.

Example 16 A reagent obtained by grinding a Zn ₃ (PO ₄ ) ₂ .4H ₂ O reagent with a ball mill using zirconia beads for 10 minutes was used as a phosphate of a divalent or trivalent metal. The concentration of the divalent or trivalent metal phosphate was adjusted to 2 g / L. The particle diameter of the suspension was measured with a submicron particle analyzer (Coulter N4: Coulter) and a Coulter counter (Coulter), and as a result, 0.31 μm and 6.5 μm.
Has a particle size distribution peak, and 6.5% of particles are 20%
Included. SiO ₂ (AEROSIL # 300: Nippon Aerosil Co., Ltd.)
After addition of a sodium tertiary phosphate reagent as an alkali metal salt, the pH was adjusted to a predetermined value as a pretreatment liquid for surface adjustment shown in Table 1.

Comparative Example 1 A surface preparation pretreatment was performed under standard conditions of an aqueous solution of Preparen ZN (registered trademark: manufactured by Nippon Parkerizing Co., Ltd.), which is a pretreatment liquid for surface preparation of a conventional product.

Comparative Example 2 As shown in Table 2, SiO ₂ (AEROSI
L # 300: manufactured by Nippon Aerosil Co., Ltd.) and pretreated for surface conditioning.

Comparative Example 3 The surface treatment pretreatment was carried out by adjusting the pH of a preparene ZN aqueous solution, which is a surface treatment pretreatment liquid of a conventional product, to the value shown in Table 2.

Comparative Example 4 A surface preparation pretreatment was carried out by adjusting the pH of a preparene ZN aqueous solution which is a conventional surface preparation pretreatment liquid to the value shown in Table 2.

Comparative Example 5 A pretreatment for surface conditioning was carried out at a treatment temperature of 40 ° C. of an aqueous solution of preparen ZN, which is a pretreatment liquid for surface conditioning of a conventional product.

Comparative Example 6 A Zn ₃ (PO ₄ ) ₂ .4H ₂ O reagent was pulverized for 10 minutes by a ball mill using zirconia beads, and used as a phosphate of a divalent or trivalent metal. The suspension of the divalent or trivalent metal phosphate was filtered through a 5 μm paper filter, and the average particle size of the filtrate was measured with a submicron particle analyzer (Coulter N4: Coulter). It was 0.31 μm. Further, the concentration of the phosphate of a divalent or trivalent metal in the filtrate was adjusted to 2 g / L. SiO ₂ (AEROSIL # 300: Nippon Aerosil Co., Ltd.)
Was added, and the pH was adjusted to a predetermined value as a pretreatment liquid for surface adjustment shown in Table 1.

Comparative Example 7 A Zn ₃ (PO ₄ ) ₂ .4H ₂ O reagent was used as a phosphate of a divalent or trivalent metal. After making the divalent or trivalent metal phosphate a suspension, the mixture was filtered through a 5 μm paper filter, and the particles remaining on the filter paper were dispersed again in water to obtain a suspension.
As a result of measuring the average particle size of the suspension using a Coulter counter (Coulter), it was 6.5 μm. Next, the concentration of the divalent or trivalent metal phosphate in the suspension was 2 g /
L was adjusted. After adding SiO ₂ (AEROSIL # 300: manufactured by Nippon Aerosil Co., Ltd.) as fine oxide particles to the suspension whose concentration has been adjusted, and a sodium tertiary phosphate reagent as an alkali metal salt, the pH is adjusted to a predetermined value. Table 1
Was prepared as a pretreatment liquid for surface adjustment shown in Table 1.

Comparative Example 8 A reagent obtained by grinding a Zn ₃ (PO ₄ ) ₂ .4H ₂ O reagent with a ball mill using zirconia beads for 10 minutes was used as a phosphate of a divalent or trivalent metal. The suspension of the divalent or trivalent metal phosphate was filtered through a 5 μm paper filter, and the average particle size of the filtrate was measured with a submicron particle analyzer (Coulter N4: Coulter). It was 0.31 μm. Further, the concentration of the phosphate of a divalent or trivalent metal in the filtrate was adjusted to 2 g / L. SiO ₂ (AEROSIL # 300: Nippon Aerosil Co., Ltd.)
After addition of a sodium tertiary phosphate reagent as an alkali metal salt, the pH was adjusted to a predetermined value as a pretreatment liquid for surface adjustment shown in Table 1.

(Zinc Phosphate Treatment Solution) Palbond L3020 (registered trademark: manufactured by Nippon Parkerizing Co., Ltd.) was diluted to 4.8% with tap water in each of the examples and comparative examples.
The total acidity, free acidity, and accelerator concentration were adjusted to the concentrations generally used at present for automatic zinc phosphate treatment. The processing steps are described below.

(Treatment process) (1) Alkaline degreasing, sprayed at 42 ° C for 120 seconds (2) Rinse with water, room temperature, sprayed for 30 seconds (3) Surface adjustment, room temperature, immersed for 20 seconds (4) Zinc phosphate treatment 42 ° C, immersed for 120 seconds (5) Rinse at room temperature for 30 seconds. (6) Deionized water wash at room temperature for 30 seconds.

(Coating and Evaluation Steps) In both Examples and Comparative Examples, a cationic electrodeposition paint (Electron 2000: manufactured by Kansai Paint Co., Ltd.) was applied so as to have a thickness of 20 μm.
After baking for 25 minutes at, a portion was subjected to a salt spray test and a salt-resistant hot water test. The remaining electrodeposited plates were coated with an intermediate coating (intermediate coating for automobiles: manufactured by Kansai Paint Co., Ltd.) so that the thickness of the intermediate coating was 40 μm, and baked at 140 ° C. for 30 minutes. Further, a top coat (automobile top coat: manufactured by Kansai Paint Co., Ltd.) was applied to the test plate after completion of the middle coat so that the film thickness of the top coat was 40 μm, and baked at 140 ° C. for 30 minutes. The obtained total film thickness of 100 μm 3
The coated plate was subjected to a primary adhesion evaluation test and a secondary adhesion evaluation test.

(Evaluation Method of Zinc Phosphate Film) (1) Appearance The presence or absence of invisibility and unevenness of the zinc phosphate film was confirmed by visual observation. The evaluation was as follows. ◎ Uniform and good appearance ○ Some unevenness △ Some unevenness and invisibility × Many invisibility ×× No conversion coating

(2) Film Weight (CW) The weight of the treated plate after the chemical conversion treatment was measured (referred to as W1 [g]). A peeling treatment was performed, and the weight was measured (W2
[G]), and calculated using the formula (I).・ In the case of cold rolled steel sheet Stripping solution: 5% chromic acid aqueous solution Stripping condition: 75 ° C, 15 minutes, immersion stripping ・ In the case of galvanized sheet Stripping solution: 2% by weight of ammonium bichromate + 28% ammonia water 49% by weight + pure 49% by weight of water Peeling condition: normal temperature, 15 minutes, immersion peeling Film weight [g / m2] = (W1-W2) /0.021 Formula (I)

(3) Film Crystal Size (CS) The deposited film crystals were observed at an magnification of 1500 times using a scanning electron microscope (SEM) to examine the crystal grain size.

(4) P ratio In both the examples and the comparative examples, the X-ray intensity (P) of the phosphophyllite crystals and the X The linear strength (H) was measured. The P ratio was calculated from the obtained X-ray intensity using the formula (II). P ratio = P / (P + H) Formula (II)

(Evaluation Method of Coating Film) In each of the Examples and Comparative Examples, the coating film was evaluated according to the following evaluation method.

(1) Salt spray test (JIS-Z-237)
1) 5% salt water was sprayed onto the cross-cut electrodeposition coated plate for 960 hours. After the spraying, the maximum rust width on one side from the cross cut was measured and evaluated.

(2) Salt-resistant hot water test A cross-cut electrodeposited plate was placed in 5% salt water for 240 minutes.
Soaked for hours. After immersion, the maximum rust width on one side from the cross cut was measured and evaluated.

(3) Evaluation Test of Primary Adhesion A 3 mm grid was cut on a 3-coated board with a sharp cutter at intervals of 2 mm.
After forming 100 pieces, the pressure-sensitive adhesive tape was adhered on a grid, and then peeled off, and the number of peeled grid-coated films was evaluated.

(4) Secondary adhesion evaluation test The 3-coated plate was immersed in deionized water at 40 ° C. for 240 hours, and after completion of the immersion, a cross-cut peel test was carried out according to the same procedure as the primary adhesion evaluation test. The number of cross-cut coating films evaluated was evaluated.

Table 3 shows the film properties of the chemical conversion film obtained by the zinc phosphate treatment using the pretreatment liquid for surface conditioning in the examples.

Table 4 shows the coating properties of the chemical conversion coating obtained in the zinc phosphate treatment using the pretreatment liquid for surface conditioning in the comparative example.

Table 5 shows the performance evaluation results of the chemical conversion coatings obtained in the zinc phosphate treatment using the preconditioning solution for surface conditioning in the examples after coating.

Table 6 shows the results of performance evaluation after coating of the chemical conversion coating obtained in the zinc phosphate treatment using the pretreatment liquid for surface conditioning in the comparative example.

From Tables 3 and 4, it is confirmed that the surface treatment pretreatment liquid of the present invention significantly improves the stability with time, which is a disadvantage of the conventional product. Further, the effects of the oxide fine particles on the stability over time are clear from Examples 1 and 2. Furthermore, even if the type of oxide fine particles and alkali metal and the processing temperature are changed, the effect is not changed, and fine and fine crystals can be obtained at least equivalent to those of the conventional product, and the divalent or trivalent metal phosphoric acid used is used. It has also become possible to control the size of the phosphate film crystals obtained by controlling the average particle size of the salt.

From Tables 5 and 6, it can be seen that the surface treatment pretreatment liquid of the present invention gives a coating performance equal to or higher than that of the conventional product.

[0086]

As described above, the product of the present invention significantly improves the stability over time, which was a disadvantage of the conventional product, and also allows free control of the crystal size of the phosphate film, which was impossible with the conventional product. . Therefore, the product of the present invention is economically advantageous as compared with the conventional product, and can provide the same or higher performance as the conventional product.

[0087]

[Table 1]

[0088]

[Table 2]

[0089]

[Table 3]

[0090]

[Table 4]

[0091]

[Table 5]

[0092]

[Table 6]

Claims (8)

[Claims] 1. A phosphoric acid salt containing at least one divalent or trivalent metal containing particles having a particle size of 5 μm or less, and an alkali metal salt or an ammonium salt or a salt thereof. Containing a mixture and p
A pretreatment liquid for surface conditioning before a metal phosphate film conversion treatment, wherein H is adjusted to 4 to 13. 2. The concentration of particles having a particle size of 5 μm or less is 0.001 to 30 g / L, and the divalent or trivalent metal is Zn, Fe, Mn, Ni, Co, Ca,
2. The pretreatment liquid for surface conditioning of a metal according to claim 1, which is at least one selected from the group consisting of Al and Al. 3. The method according to claim 2, wherein the alkali metal salt or ammonium salt is an orthophosphate, a metaphosphate, an orthosilicate,
The metal according to claim 1, which is at least one kind of salt selected from metasilicate, carbonate, bicarbonate, and borate, and has a concentration of 0.5 to 20 g / L. Pretreatment liquid for surface conditioning before phosphate film chemical conversion treatment. 4. An oxide fine particle anionically charged and dispersed in an aqueous solution, an anionic water-soluble organic polymer, a nonionic water-soluble organic polymer, an anionic surfactant,
The preconditioning solution for surface conditioning before a metal phosphate film conversion treatment according to claim 1, comprising at least one selected from the group consisting of a nonionic surfactant and a nonionic surfactant. 5. The metal according to claim 4, wherein the anionically charged and dispersed oxide fine particles have an average particle size of 0.5 μm or less and a concentration of 0.001 to 5 g / L. Pretreatment liquid for surface conditioning before phosphate film chemical conversion treatment. 6. The anionic charged and dispersed oxide fine particles are composed of Si, B, Ti, Zr, Al, Sb, Mg, S
5. The surface preparation before metal phosphate conversion treatment according to claim 4, wherein the metal is at least one selected from the group consisting of oxides of e, Zn, Sn, Fe, Mo, and V. Processing liquid. 7. A method for forming a phosphate conversion coating on a metal surface, wherein the metal surface is brought into contact with the preconditioning solution for surface conditioning according to claim 1 in advance. Surface conditioning method before metal phosphate coating conversion treatment. 8. When forming a phosphate conversion coating on a metal surface, the metal surface is previously treated with a nonionic surfactant or an anionic surfactant, or a combination thereof, for both activation and cleaning of the metal surface. A surface conditioning method before a metal phosphate film chemical conversion treatment, wherein the mixture is brought into contact with the surface conditioning pretreatment liquid according to any one of claims 1 to 6 containing a builder. [0001]