JP2006111937A - One-side phosphate treatment method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for forming a satisfactory phosphate film on only one side of Zn-based plated metal sheets which are continuously passed. <P>SOLUTION: In this method, a surface control treatment liquid is applied only to either side of a Zn-based plated metal sheet to be continuously passed, and next, it is contacted with a phosphate treatment liquid for 1 to 10 s. It is also possible that the surface control treatment liquid is applied using a roll coater. Further, the method of contacting the same with the phosphate treatment liquid is performed, e.g., by spraying treatment. Also, it is also possible that air or inert gas may be blown against the opposite face to be sprayed with the phosphate treatment liquid. By the method, a satisfactory phosphate film is formed on only either side of the Zn-based plated metal sheet to be continuously passed, and the same is not formed on the other side so as to retain satisfactory appearance. Thus, the production method useful in the case one side phosphate treatment is desired can be provided. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for forming an excellent phosphate film only on one surface of a Zn-based plated metal plate that is continuously passed.

  As a surface treatment of a Zn-based plated metal plate typified by a galvanized steel plate, a phosphate treatment is widely used. In particular, phosphate-treated galvanized steel sheets with improved corrosion resistance and paintability are also known for automotive applications (see, for example, Patent Document 1).

WO 00/73535 A1

  In the case of automotive applications, after processing and assembly, phosphating is often performed as pre-painting treatment (the phosphating treatment here is called post-phosphate treatment for distinction). Since post-phosphate treatment exists, depending on the compatibility of the phosphate treatment and post-phosphate treatment of the steel sheet, there may be problems in the appearance and adhesion of the coating. Also, on the surface corresponding to the outer surface of a car, post-phosphate treatment and painting are sufficient, so that the phosphate treatment of the steel sheet is not always necessary.

  In such a case, it is preferable to perform phosphating only on one side of the steel sheet (that is, the surface that becomes the inner surface of the automobile), but it is not possible to apply phosphating on only one side at the laboratory level. Even if possible, it was extremely difficult industrially. This is because in order to allow the treatment liquid to contact only one side of the metal plate that passes continuously at high speed and not to contact the other side, a complete coating type treatment is necessary. With regard to phosphating, the performance of the formed phosphate film is insufficient, and in normal phosphating such as dipping and spraying, it is necessary to completely seal the opposite surface so that the treatment solution does not adhere to it. There was a problem that the formation of a phosphate film was unavoidable in part or it was not possible to produce a product due to poor appearance.

  In view of the above situation, an object of the present invention is to provide a method for forming a good phosphate film only on one surface of a Zn-based plated metal plate that is continuously passed.

  First, with reference to FIG. 1, a normal double-sided phosphate treatment comprising surface conditioning treatment, phosphate treatment, and water washing will be described. The metal plate 1 is fed rightward in the horizontal direction in FIG. 1 through the ringer rolls 2 arranged in the upper and lower pairs. During this conveyance, the surface adjustment treatment liquid 4 is supplied from the surface adjustment treatment solution spray header 3 to both surfaces (upper and lower surfaces) of the metal plate 1, and then the phosphate treatment solution spray header 5 is subjected to the phosphate treatment. The liquid 6 is supplied, and the flush water 8 is further supplied from the flush water spray header 7.

  In such a double-sided phosphate treatment facility, if treatment is to be performed only on one side (for example, the lower surface) of the metal plate 1, the treatment liquids 4 and 6 can be sprayed only on one side as shown in FIG. Conceivable. Here, on the opposite surface (for example, the upper surface), a gas such as air 10 may be blown from the air spray header 9 in order to seal the processing liquids 4 and 6.

  However, even if the method as shown in FIG. 2 is adopted, it is difficult to completely suppress adhesion of the opposite surface and maintain a good appearance. This is thought to be because the reaction proceeds even with fume-level liquid adhesion.

  As a result of various studies, the present inventors have completely prevented the adhesion of the surface conditioning treatment liquid on one side, and if the conditions for the phosphating treatment are appropriate, It was found that the formation of the film can be suppressed even if there is adhesion, and that a good film can be obtained on the surface treated with phosphoric acid.

  Based on this knowledge, according to the present invention, the surface conditioning treatment liquid is applied only to one surface of the Zn-based plated metal plate that is continuously passed, and then the phosphate treatment liquid is contacted for 1 to 10 seconds. A single-sided phosphating method is provided.

  In this case, the surface adjustment treatment liquid may be applied using a roll coater. Moreover, the method of making it contact with a phosphate processing liquid is performed by spraying, for example. In addition, air or inert gas may be sprayed on the opposite surface on which the phosphating solution is sprayed.

  According to the present invention, a good phosphate film is formed only on one surface of a continuously plated Zn-based plated metal plate, and a good appearance is maintained without forming a phosphate film on the other surface. And a useful production method can be provided when single-side phosphating is desired.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 3 is an explanatory diagram of the single-side phosphating treatment facility according to the embodiment of the present invention.

  As in the case described with reference to FIGS. 1 and 2, the metal plate 1 (Zn-based plated metal plate) is continuously fed to the right in the horizontal direction in FIG. 3 through the ringer rolls 2 arranged vertically. It has been. Here, the Zn-based plated metal plate used in the present invention is a Zn-plated steel plate as a representative example, and shows various Zn-based alloy-plated steel plates containing Zn, a Zn-based plated aluminum plate, or the like. A steel plate, an aluminum plate, or the like obtained by flash plating a small amount of Zn or a Zn-based alloy is also included in the Zn-based plated metal plate in the present invention.

  In front of the ringer roll 2, a backup roll 11 and a coating roll 12 are arranged in a pair on the top and bottom, and the surface is adjusted only on the lower surface of the metal plate 1 through the backup roll 11 and the coating roll 12. After the treatment liquid 4 is applied, the metal plate 1 passes between the ringer rolls 2.

  In the example shown in FIG. 3, a surface adjustment treatment liquid receiving pan 14 storing the surface adjustment treatment liquid 4 is disposed below the application roll 12, and the application roll 12 is placed on the surface adjustment treatment liquid reception pan 14. It is located above the liquid level of the stored surface conditioning liquid 4. Between the coating roll 12 and the surface adjustment processing liquid receiving pan 14, the surface adjustment processing liquid receiving pan 14 rotates with a part of the peripheral surface immersed in the liquid of the surface adjustment processing liquid 4 stored in the surface adjustment processing liquid receiving pan 14. The pick-up roll 13 is interposed, and the surface conditioning treatment liquid 4 attached to the peripheral surface of the pick-up roll 13 is attached to the peripheral surface of the application roll 12, and the peripheral surface of the application roll 12 is brought into contact with the lower surface of the metal plate 1. Thus, the surface adjustment treatment liquid 4 is applied to the lower surface of the metal plate 1. The surface conditioning treatment liquid 4 is a so-called reverse roll that rotates in the direction opposite to the feeding direction of the metal plate 1. In the illustrated embodiment, the metal plate 1 is conveyed rightward in the figure. Thus, the surface conditioning treatment liquid 4 rotates in the counterclockwise direction.

  The surface conditioning treatment liquid 4 applied to the lower surface of the metal plate 1 by the application roll 12 as described above is a treatment liquid that forms nuclei for forming phosphate crystals prior to the phosphate treatment, and is generally used. Examples include titanium colloid, phosphate colloid, and noble metal ions.

  Further, behind the ringer roll 2, a phosphate treatment liquid spray header 5 for supplying the phosphate treatment liquid 6 and a flush water spray header 7 for supplying the washing water 8 are arranged. . The phosphating solution spray header 5 is disposed below the metal plate 1 and supplies the phosphating solution 6 only to the lower surface of the metal plate 1 that is continuously passed through. Further, an air spray header 9 is disposed above the metal plate 1 so as to face the phosphating solution spray header 5. By blowing a gas such as air 10 from the air spray header 9, the metal The phosphating solution 6 supplied to the lower surface of the plate 1 is prevented from entering the upper surface of the metal plate 1.

  Thus, the phosphating solution 6 supplied from the phosphatizing solution spray header 5 to the lower surface of the metal plate 1 is a processing solution for generating so-called hopite crystals, and includes phosphate ions, Zn ions, and other metal ions. (Ion such as Ni, Mn, Mg, Co, Cu), reaction accelerator (F ion, nitrate ion, nitrite ion) and the like. Specifically, a treatment liquid containing phosphate ions 5 to 20 g / l, Zn ions 0.5 to 3 g / l, Ni and / or Mn 0.2 to 6 g / l, and F ions 0.1 to 1 g / l. is there. If any component is less than the lower limit, it is difficult to form a good phosphate film, and if it exceeds the upper limit, the appearance of the surface on which the phosphate film is not formed becomes poor. Further, for the purpose of further improving the perforated corrosion resistance of the steel plate, it is also preferable to additionally add 10-30 g / l of Mg ions in addition to the treatment liquid. It should be noted that the phosphate treatment liquid supplied from the phosphate treatment liquid spray header 5 to the lower surface of the metal plate 1 depending on the number of installed phosphate treatment liquid spray headers 5 and the interval between them and the plate speed of the metal plate 1. The contact time (reaction time) 6 can be arbitrarily set.

  On the other hand, the flush water spray headers 7 are arranged on both the upper and lower sides of the metal plate 1, and flush water 8 is supplied to both upper and lower surfaces of the metal plate 1 that is continuously passed.

  In the single-side phosphating treatment equipment as described above, the metal plate 1 is continuously passed to the right in the horizontal direction in FIG. 3. First, the surface conditioning treatment liquid 4 is applied only to the lower surface of the metal plate 1 by the coating roll 12. Apply. Next, the phosphate treatment liquid 6 is supplied from the phosphate treatment liquid spray header 5 to the lower surface of the metal plate 1, the contact time of the phosphate treatment liquid 6 is set to 1 to 10 seconds, and then the washing water spray header 7 The rinsing water 8 is supplied to the upper and lower surfaces of the metal plate 1 and washed with water, followed by drying treatment.

  Thus, after applying the surface conditioning treatment liquid 4 to the lower surface of the metal plate 1 to form an acid salt film only on the lower surface of the metal plate 1, the contact time is set to 1 to 10 seconds and the treatment with the phosphate treatment liquid 6 is performed. By doing so, the phosphate film is not formed on the opposite surface (upper surface) of the metal plate 1, and the appearance is also kept in a good state. Here, when the contact time of the phosphate treatment liquid 6 is less than 1 second, a good phosphate film cannot be obtained, and when it exceeds 10 seconds, the phosphate film is not formed on the surface (upper surface) of the phosphate film. Will be formed or the appearance will be poor. In order to keep the appearance of the phosphate film non-formation surface better, as shown in FIG. 3, the treatment liquid is sprayed on the phosphate film formation surface (lower surface) and the non-formation surface (upper surface) is sprayed. Is preferably blown with air or inert gas.

  As mentioned above, although an example of embodiment of this invention was demonstrated, this invention is not limited to the form demonstrated here. FIG. 4 is an explanatory view of a single-sided phosphating treatment facility according to another embodiment of the present invention.

  The single-side phosphating treatment facility shown in FIG. 4 basically has the same configuration as the single-side phosphating treatment facility described in FIG. 3, and therefore, common components are denoted by the same reference numerals. However, in the single-side phosphating treatment facility shown in FIG. 4, instead of the coating roll 12 shown in FIG. 3, the metal plate 1 rotates in the clockwise direction in the same direction as the plate feed direction. The surface adjustment treatment liquid 4 is applied to the lower surface of the metal plate 1 using the application roll 15. A liquid cutting roll 16 is provided in the vicinity of the coating roll 15, and the surface adjustment processing liquid 4 is supplied from the surface adjustment processing liquid spray header 3 to the contact portion between the coating roll 15 and the liquid cutting roll 16, thereby applying the liquid. The surface conditioning treatment liquid 4 adhered to the peripheral surface of the roll 12 is applied to the lower surface of the metal plate 1. In addition, an air spray header 9 is disposed above the metal plate 1 in the vicinity of the backup roll 11 so as to face the coating roll 12, and a gas such as air 10 is blown from the air spray header 9. Thus, the surface adjustment treatment liquid 4 applied to the lower surface of the metal plate 1 is prevented from entering the upper surface of the metal plate 1.

  In the case of applying the surface conditioning treatment liquid 4 to the metal plate 1 using a so-called roll coater, a type in which the surface adjustment processing liquid 4 is applied in the reverse direction with respect to the plate passing direction of the metal plate 1 as described in FIG. Any of the types that are applied by rotating forward as shown in Fig. 6 can be used. In the present invention, the application of the surface adjustment treatment liquid to one surface of the metal plate 1 means that a part or all of the surface adjustment treatment liquid existing on the surface of the application object such as a roll, a bar, or a blade is an object to be applied. It means transferring to one side of a metal plate. Considering productivity at high speed, coating with a roll coater is preferable. In addition, as described with reference to FIG. 4, it is preferable to blow air or an inert gas on the opposite surface in order to minimize the flow of the processing liquid from the edge portions (both sides) of the metal plate 1.

  3 and 4, the example in which the surface adjustment treatment liquid 4 is applied only to the lower surface of the metal plate 1 has been described in each case, but the surface adjustment treatment liquid 4 is applied only to one surface of the metal plate 1. The surface adjustment treatment liquid 4 may be applied only to the upper surface of the metal plate 1.

Examples of the present invention will be described below.
In Examples 1 to 3 and Comparative Example 1, the electrogalvanized steel sheet (double-sided plating, Zn deposition amount 20 g / m ² ) was processed by the method described in FIG. The surface conditioning treatment solution was a titanium colloid-based commercial treatment solution and applied at 40 ° C. The phosphating solution uses Zn ions 1 g / l, phosphate ions 10 g / l, Ni ions 2.5 g / l, Mg ions 20 g / l, F ions 0.2 g / l, and 60 ° C. The process was performed. The phosphate treatment time was variously changed as shown in Table 1.

In Example 4, the electrogalvanized steel sheet (double-sided plating, Zn deposition amount 20 g / m ² ) was processed by the method described in FIG. The surface conditioning treatment solution was a titanium colloid-based commercial treatment solution and applied at 40 ° C. The phosphating solution uses Zn ions 1 g / l, phosphate ions 10 g / l, Ni ions 2.5 g / l, Mg ions 20 g / l, F ions 0.2 g / l, and 60 ° C. The process was performed. The phosphating time was 4 seconds.

In Comparative Examples 2 and 3, the electrogalvanized steel sheet (double-sided plating, Zn deposition amount 20 g / m ² ) was processed by the method described in FIG. As the surface conditioning treatment solution, a titanium colloid-based commercial treatment solution was used and sprayed at 40 ° C. The phosphating solution used has the following concentrations: Zn ion 1 g / l, phosphate ion 10 g / l, Ni ion 2.5 g / l, Mg ion 20 g / l, F ion 0.2 g / l. The process was performed. The phosphate treatment time was variously changed as shown in Table 1.

(Performance evaluation method)
(1) Phosphate film non-formation surface (surface)
Presence / absence of coating: The presence or absence of a phosphate coating was observed by optical microscope (× 500) observation and SEM observation (× 1000, 5000). The case where no phosphate film could be detected was indicated as “◯”.
Appearance: Unevenness was observed visually. “No” indicates no unevenness.

(2) Phosphate film forming surface (back surface)
Amount of adhesion: The amount of adhesion g / m ² per side was determined by fluorescent X-ray analysis.
Appearance: Unevenness was observed visually. “No” indicates no unevenness.
Characteristics: The crystal properties by SEM observation (× 1000, 5000) and the presence or absence of a Hope structure by X-ray diffraction analysis were observed.
The above evaluation results are shown in Table 1.

  In Examples 1 to 4 of the present invention, good characteristics were obtained, but in Comparative Examples 1 to 3 deviating from the scope of the present invention, the characteristics deteriorated.

  The present invention is applied to, for example, a phosphate-treated galvanized steel sheet for automobile use.

It is explanatory drawing of the conventional normal double-sided phosphate processing equipment. It is explanatory drawing of the conventional normal single-sided phosphate processing equipment. It is explanatory drawing of the single-sided phosphatization equipment concerning embodiment of this invention. It is explanatory drawing of the single-sided phosphatization equipment concerning another embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1; Metal plate 2; Ringer roll 3; Surface adjustment processing liquid spray header 4; Surface adjustment processing liquid 5; Phosphate processing liquid spray header 6; Phosphate processing liquid 7; Flushing water spray header 8; Flushing water 9; Air spray header 10; air 11; backup roll 12; coating roll (reverse roll)
13; Pickup roll 14; Surface adjustment treatment liquid receiving pan 15; Application roll 16;

Claims (4)

  A single-side phosphating method characterized in that a surface conditioning treatment solution is applied only to one surface of a Zn-based plated metal plate that is continuously passed, and then a phosphating solution is contacted for 1 to 10 seconds. .   2. The single-sided phosphating method according to claim 1, wherein the surface conditioning treatment liquid is applied using a roll coater.   The single-sided phosphating method according to claim 1 or 2, wherein the method of bringing into contact with the phosphating solution is a spraying process.   The single-side phosphating method according to claim 1, 2 or 3, characterized in that air or an inert gas is blown on the opposite surface on which the phosphating solution is sprayed.

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