JP2009214097A - Facility and method for manufacturing surface-treated steel sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a facility and a method for manufacturing a surface-treated steel sheet, in each of which a coating material can be reused, two or more coating materials can be used which are prepared by halfway changing a mixing ratio of chemicals or by halfway changing one chemical to another chemical or which are apt to react with one another at around room temperature, or two or more chemicals can be used which are apt to generate sludge due to a neutralization reaction. <P>SOLUTION: The facility for manufacturing the surface-treated steel sheet is characterized in that two or more ink-jet units each having a plurality of heads 11-13 are arranged along the traveling direction of a steel sheet 10 and the plurality of heads of each of two or more ink-jet units are arranged along the width direction of the steel sheet. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a surface-treated steel sheet used in fields such as automobiles, home appliances, and building materials, and more particularly to equipment and a method for producing a surface-treated steel sheet having a coating film formed from two or more kinds of paints on the surface.

  Conventionally, as a steel sheet used in the fields of automobiles, home appliances, building materials, etc., a coating containing two or more kinds of chemicals has been applied to the surface for the purpose of improving corrosion resistance, adhesion, scratch resistance, chemical resistance, etc. A surface-treated steel sheet having a coating film formed as described above has been proposed. For example, Patent Document 1 is a surface-treated steel sheet in which a film containing a crosslinked resin matrix and an inorganic rust preventive agent is formed, and the crosslinked resin matrix is formed by a reaction between an aqueous resin and a crosslinking agent, A surface-treated steel sheet in which the acid value and hydroxyl value of a carboxylic acid not neutralized with an alkali metal are adjusted is disclosed. In Patent Document 2, an isocyanate compound blocked with an alkyl etherified melanin resin and / or an oxime block agent as a curing agent on a polyester resin and / or acrylic polyester resin having a specific molecular weight and glass transition temperature, A pre-coated steel sheet (surface-treated steel sheet) having a coating film formed from a coating composition blended with a crosslinked and cured colored spherical resin powder in the uppermost layer is disclosed. In Patent Document 3, a polyfunctional polyisocyanate compound and sparingly soluble chromium are added to a base resin having a chromate film on the surface of a zinc-based plated steel sheet, and a primary hydroxyl group added to the end of the epoxy resin on the chromate film. An organic composite-coated steel sheet (surface-treated steel sheet) having an organic film formed by applying a coating composition containing an acid salt is disclosed. Patent Document 4 applies zirconium, fluorine, a silane coupling agent, a chemical conversion treatment agent composed of a phenolic compound, and consumes fluorine by dissolution reaction such as a plating layer on the surface of a steel sheet, whereby zirconium hydroxide or A surface-treated steel sheet in which an oxide is formed is disclosed. In Patent Document 5, a metal salt composed of a specific metal and a phosphate, nitrate, carbonate, or the like reacts with a zinc-based plating dissolved with an acid, thereby forming a strong film via an ionic bond. A plated steel sheet is disclosed.

JP 2005-281863 JP Japanese Unexamined Patent Publication No. 3-71835 JP 7-118870 A JP 2006-241579 A JP 2008-57047 A

  However, in the surface-treated steel sheets described in Patent Documents 1 to 5, since the coating film is formed by applying a paint containing two or more kinds of chemicals to the steel sheet by a roll coater or spray, the following is performed. Problems arise.

  i) Since paints containing two or more chemicals are used, paints that are no longer needed cannot be reused.

  ii) Since the paint is prepared before application, it is difficult to change the compounding ratio and type of the drug on the way.

  iii) Since the paint is prepared before application, it may not be possible to use chemicals that easily react near room temperature or chemicals that easily generate sludge due to a neutralization reaction.

  The present invention is a facility for producing a surface-treated steel sheet that enables reuse of paints, changes in the mixing ratio and type of chemicals, and chemicals that are likely to react near room temperature, or that are prone to sludge due to a neutralization reaction. And it aims at providing a manufacturing method.

  The inventors of the present invention have developed a surface-treated steel sheet that enables the use of chemicals that are likely to react with each other, such as reuse of paint, change of the mixing ratio and type of chemicals, and reaction near room temperature, or neutralization reaction. As a result of earnest research on manufacturing, two or more ink jet devices were used, and each drug constituting the paint was ejected as droplets from the heads provided in the separate ink jet devices as separate paints. The present inventors have found that the coating film may be formed by landing on the steel plate surface.

  The present invention has been made on the basis of such knowledge, and two or more inkjet devices provided with a plurality of heads are installed along the traveling direction of the steel sheet, and the plurality of inkjet devices provided in each inkjet device. The head of this invention provides the manufacturing equipment of the surface treatment steel plate arrange | positioned along the width direction of a steel plate.

  In the production facility of the present invention, a water washing device and / or a heat treatment device can be arranged downstream of the position where the head of the ink jet device is arranged.

  The present invention also uses the above-described surface-treated steel sheet manufacturing equipment, and two or more kinds of paints are each discharged as droplets from a plurality of heads provided in different ink jet devices and sequentially landed on the steel sheet surface. A method for producing a surface-treated steel sheet for forming a coating film is provided.

  In the production method of the present invention, after the coating material is landed on the surface of the steel sheet, the coating film can be formed by washing with water and / or heat treatment.

  Further, the blending ratio of the paint can be changed by changing the ratio of the droplet amount for each paint.

  Examples of the two or more types of paint include a paint containing an organic resin and a paint containing a curing agent and / or a lubricant, or a paint containing at least a basic component and an acidic component.

  According to the present invention, paints can be reused, the mixing ratio and type of drugs can be changed in the middle, and drugs that react easily near room temperature, or drugs that easily generate sludge due to a neutralization reaction may be used. No surface-treated steel sheet can be manufactured.

It is explanatory drawing of the manufacturing method of the surface treatment steel plate using the inkjet apparatus which is this invention. It is a figure which shows an example of head arrangement | positioning of the inkjet apparatus which is this invention. It is a figure which shows an example of the manufacturing equipment of the surface treatment steel plate using the inkjet apparatus which is this invention. It is a figure which shows an example of the manufacturing equipment of the surface treatment steel plate using the inkjet apparatus which is this invention.

  An ink jet printer is a printing machine that ejects ink as fine droplets from a head having a large number of ejection openings (nozzles) by a piezo method or a thermal method and directly lands on a print medium such as paper. In the present invention, the surface of the ink jet printer is formed on the surface of the steel sheet with a coating film composed of a paint containing two or more kinds of chemicals for the purpose of improving corrosion resistance, adhesion, scratch resistance, chemical resistance, and the like. Applying to treated steel plates, reusing paints that were not possible in the past, changing the mixing ratio and type of chemicals, chemicals that react easily at room temperature, or chemicals that are prone to sludge due to neutralization reaction It is characterized by enabling use.

  FIG. 1 shows an example of equipment for producing the surface-treated steel sheet of the present invention. In this example, three inkjet devices (not shown) are installed along the traveling direction of the steel plate, and a plurality of heads provided in each inkjet device, that is, a plurality of heads 11, a plurality of heads 12, A plurality of heads 13 are arranged along the width direction of the steel plate, respectively, above the steel plate surface in the vertical direction. At this time, the plurality of heads 11, the plurality of heads 12, and the plurality of heads 13 provided in each inkjet device are shown in FIG. 2 in the case of six heads for each inkjet device, but in the width direction of the steel plate 10. In order to form a uniform coating film, it is preferable to arrange them along the same direction. 1 and 2 show a case where a plurality of heads are arranged vertically above a substantially horizontal steel plate surface, but when the steel plate surface is substantially parallel to the vertical direction, What is necessary is just to arrange | position each head in the position where the droplet of the coating material discharged from a head lands on the steel plate surface, and can form a coating film.

  Although the same thing as a commercially available ink jet printer can be applied to the ink jet device used in the production facility of the present invention, since it is intended for coating film formation on a large area such as a surface-treated steel plate, depending on the size of the steel plate It is preferable that the capacity of the coating material supply system, the size and number of heads, and the like can be changed as appropriate.

  As shown in FIG. 1 (a), paint 22 is ejected from head 12 and paint 21 is ejected as droplets from head 11, and sequentially landed on the surface of steel sheet 10. Can be formed. By providing a heat treatment device on the downstream side of the position where the head of the ink jet device is arranged, a heat treatment can be performed to form a coating film. Further, by providing a water washing device on the downstream side from the position where the head of the ink jet device is arranged, it is possible to form a coating film by washing with water. Further, by providing a heat treatment device on the downstream side of the water washing device, it is possible to form a coating film by performing heat treatment after washing with water. By such heat treatment, a coating film forming reaction from the coating material to the coating film, a curing reaction between the organic resin and the curing agent in the coating material, and the like can be promoted. Moreover, unnecessary components such as a high boiling point solvent such as a humectant contained in the paint can be removed by washing with water, and a clean coating film can be formed.

  At this time, the paint 21 stored in the ink jet device equipped with the head 11 and the paint 22 stored in the ink jet device equipped with the head 12 do not mix until landing on the surface of the steel plate 10, and the sludge is neutralized. Can be reused.

  By changing the discharge amount for each ink jet apparatus, that is, for each paint, specifically, by changing the droplet amount of the paints 21 and 22 to be discharged, it is possible to form coating films having different blending ratios of the paints 21 and 22. At this time, in order to change the appropriate amount of liquid, the number of nozzles used in each head and the number of droplets ejected from the nozzles may be changed.

  As shown in FIG. 1 (b), if the coating material 23 is further ejected as droplets from the head 13, a coating film containing the coating materials 21 and 23 can be formed. Also, if you select paints such as paints 21 and 22, paints 21 and 22, paints 22 and 23, you can form different types of paint film, and if you add an inkjet device, you can choose the type of paint film that can be formed. It becomes possible to increase.

  In a conventional roll coater or the like, when agents that easily react at around room temperature are mixed before coating to form a paint, the properties such as viscosity may change due to the reaction, thereby making it impossible to form a coating film. However, as in the present invention, a coating film can be formed without any problems if a reactive chemical is discharged as a liquid from another head as a separate paint and landed on the surface of the steel sheet.

  Also, in conventional immersion treatment and spray treatment, etc., a coating film is formed by utilizing the reaction between the plating metal and a specific component during chemical conversion treatment, so that the reaction layer thickness control and sludge generation suppression, resin and lubricant There are problems such as restrictions on additives. However, as in the present invention, if the paint containing the basic component and the paint containing the acidic component are separated as different paints, discharged as droplets from another head, and landed on the steel sheet surface, there is no such problem. A coating film can be formed.

  Also, as shown in FIG. 3, if the traveling direction of the steel sheet 10 is changed using rolls 31, 32, etc., and the head 11, the head 12, and the heat treatment apparatus 40 are arranged, a coating film can be formed on the front and back surfaces of the steel sheet 10. In addition, heat treatment can be performed. Furthermore, as shown in FIG. 4, if a water washing device 50 is disposed upstream of the heat treatment device 40, the heat treatment can be performed after the water washing.

  The present invention includes, for example, a surface-treated steel sheet having a coating film in which a paint containing an organic resin is blended with a paint containing an organic resin on a steel sheet surface, and a paint containing a basic component on the steel sheet surface. It can be applied to a surface-treated steel sheet on which a metal hydroxide or metal oxide coating film has been formed by a neutralization reaction with a paint containing an acidic component.

Two rows of heads 11 with 6 heads arranged in the width direction as shown in Fig. 2 on an electrogalvanized steel sheet with a thickness of 0.7mm and a width of 200mm (plating amount per side: 20g / m ² ) 2 and 12 are used, and under the conditions shown in Table 1, a paint containing an epoxy resin [Epicoat (registered trademark) 1007 manufactured by Japan Epoxy Resin Co., Ltd.] and tolylene diisocyanate as a curing agent [Japan Polyurethane Industry Co., Ltd. Coronate (registered trademark) T-80] paint or lubricant droplets of a paint containing polyethylene wax [Clariant Japan Co., Ltd. Celidust (registered trademark) 3620] is discharged, sequentially, After landing on the steel plate surface, the steel plate was heated to 140 ° C. in a high-frequency induction heating furnace to produce surface-treated steel plates 1 to 8 on which a coating film having a thickness of 1.0 μm was formed. At this time, the tips of the heads 11 and 12 are at a height of 2 mm from the steel plate surface, and the moving speed of the steel plate is 20 m / min. Each of the heads 11 and 12 is of a type that forms droplets by a piezo method, and 512 nozzles are arranged in a width of 36 mm with an inter-nozzle distance of 70.5 μm. The appropriate amount of liquid discharged from each nozzle was 42 pL (picoliter), and was discharged at a frequency of 4.3 kHz. The blending ratio of the epoxy resin and the curing agent or lubricant was adjusted by changing the amount of paint droplets and the number of nozzles used.

  As a comparison, a paint containing pre-mixed drugs 1 and 2 shown in Table 2 was applied by a roll coater, and then the steel sheet was heated to 140 ° C. in a high-frequency induction heating furnace to form a coating film having a thickness of 1.0 μm. Example surface-treated steel sheets 9 to 16 were produced.

  And the uniformity of the coating-film film thickness of a steel plate width direction, the adhesiveness of a coating film, white rust resistance, and damage resistance were investigated with the following method.

Uniformity of coating film thickness: Each sample was divided into three in the width direction, and the amount of adhesion (C intensity) near the center was measured using fluorescent X-rays, and evaluated as follows.
○: Variation in adhesion in the width direction is less than 20% △: Variation in adhesion in the width direction is 20% or more and less than 50% ×: Variation in adhesion in the width direction is 50% or more Coating film adhesion: Melamine for each sample After applying a paint coating (baking 30 μm) to the steel substrate with a cutter knife in a grid pattern (10 × 10, 1 mm interval), paste with cellophane adhesive tape. A wearing / peeling test was performed, and the peeled area ratio of the coating film was measured and evaluated as follows.
◎: No peeling ○: Peeling area ratio less than 5% △: Peeling area ratio 5% or more and less than 20% ×: Peeling area ratio 20% or more White rust resistance: Neutral salt spray test for each sample (JIS-Z- 2371-2000) was subjected to a salt spray test, and the white rust area ratio after 48 hours was measured and evaluated as follows.
◎: White rust generation area ratio 5% or less ○: White rust generation area ratio 5% or more and less than 10% ○-: White rust generation area ratio 10% or more and less than 25% △: White rust generation area ratio 25% or more and less than 50% ×: White rust generation area ratio of 50% or more Scratch resistance: Using a rubbing tester (manufactured by Taihei Rika Kogyo Co., Ltd.), the test piece was corrugated, surface pressure 9.8 kPa, sliding distance 60 mm, speed 120 mm / s, After rubbing under the condition that the rubbing frequency was 1000 times, the part subjected to sliding of the test piece was visually observed and evaluated as follows.
◎: The number of cocoons is 0. ○: The number of cocoons is 1-2. △: The number of cocoons is 3-10. ×: The number of cocoons is 11 or more or discoloration (number cannot be measured).
The results are shown in Table 3. Using the manufacturing equipment of the surface-treated steel sheet in which the inkjet apparatus according to the present invention is installed, the coating method for forming the coating film is performed by applying a conventional paint compounded with a roll coater by the method for manufacturing the surface-treated steel sheet according to the present invention. It can be seen that the same surface treated steel sheet is obtained.

  The same electrogalvanized steel sheet as in Example 1, using the same ink jet apparatus as in Example 1, under the conditions shown in Table 4, sodium hydroxide solution as a paint containing a basic component and sulfuric acid as a paint containing an acidic component After droplets of zinc solution or aluminum sulfate solution were discharged and landed sequentially on the steel plate surface, the plate was washed with water, and the steel plate was heated to 140 ° C. in a high-frequency induction heating furnace to prepare surface-treated steel plates 17 to 24. At this time, as a solvent for dissolving sodium hydroxide, zinc sulfate, and aluminum sulfate, an aqueous solution containing 20 parts by mass glycerin, 1.5 parts by mass isopropyl alcohol, 0.05 parts by mass polyoxyethylene cetyl ether with respect to 80 parts by mass of water. Using. Further, various conditions of the ink jet device and the moving speed of the steel plate were the same as in the case of Example 1.

  As a comparison, after immersion for 30 seconds in a paint premixed with Drug 3 and Drug 4 shown in Table 5, wash with water, heat the steel plate to 140 ° C. in a high-frequency induction heating furnace, Produced.

  Then, the film thickness of the coating film and the uniformity of the coating film thickness in the steel sheet width direction were investigated by the following method, and the adhesion of the coating film was investigated by the method shown in Example 1.

Film thickness of coating film: For each sample, the adhesion amount (O intensity) at the center in the width direction was measured using fluorescent X-rays and evaluated as follows.
◎: The increase rate of the O strength of the sample compared to the O strength of the galvanized state (untreated) is 50% or more ○: The increase rate of the sample O strength of the galvanized state (untreated) compared to the O strength of 20 % Or more and less than 50% △: O-strength of the sample O strength as compared to the O-strength of galvanized (untreated) 5% or more and less than 20% ×: O of the galvanized as-sampled O-strength (untreated) The rate of increase compared to the strength is less than 5%. Uniformity of the coating film thickness: For each sample, divide it into three in the width direction, and measure the amount of adhesion (O intensity) near the center using fluorescent X-rays. It was evaluated as follows.
○: Variation in the adhesion amount in the width direction is less than 20% Δ: Variation in the adhesion amount in the width direction is 20% or more and less than 50% ×: Variation in the adhesion amount in the width direction is 50% or more The results are shown in Table 6. In the surface-treated steel sheet formed by the method of the present invention using the surface-treated steel sheet manufacturing equipment installed with the inkjet apparatus according to the present invention, a sufficient amount of adhesion (film thickness) of metal hydroxide or metal oxide It turns out that the coating film of a thing is formed with uniform film thickness, and its adhesiveness is also favorable. On the other hand, in the conventional surface-treated steel sheet formed by coating with a paint mixed with a chemical in advance, the film thickness is uniform, but only a coating film with insufficient adhesion can be obtained and its adhesion is poor. ing.

10 Steel plate
11-13 heads
21-23 paint
31, 32 rolls
40 Heat treatment equipment
50 Flushing device

Claims (7)

  Two or more ink jet devices equipped with a plurality of heads are installed along the traveling direction of the steel plate, and a plurality of heads equipped with each ink jet device are arranged along the width direction of the steel plate. Manufacturing equipment for surface-treated steel sheets.   2. The equipment for producing a surface-treated steel sheet according to claim 1, further comprising a water washing device and / or a heat treatment device on the downstream side of the position where the head of the inkjet device is disposed.   Using the facility for manufacturing a surface-treated steel sheet according to claim 1, two or more kinds of paints are respectively ejected as droplets from a plurality of heads provided in different ink jet devices, and are sequentially landed on the steel sheet surface. A method for producing a surface-treated steel sheet for film formation.   After the surface-treated steel sheet manufacturing facility according to claim 2 is used, two or more kinds of paints are each ejected as droplets from a plurality of heads provided in different ink jet devices, and sequentially landed on the steel sheet surface. A method for producing a surface-treated steel sheet, which is subjected to water washing and / or heat treatment to form a coating film.   5. The method for producing a surface-treated steel sheet according to claim 3, wherein the ratio of the droplet amount for each paint is changed.   6. The method for producing a surface-treated steel sheet according to claim 3, wherein a paint containing an organic resin and a paint containing a curing agent and / or a lubricant are used as the two or more kinds of paint.   6. The method for producing a surface-treated steel sheet according to claim 3, wherein a paint containing at least a basic component and a paint containing an acidic component are used as the two or more kinds of paint.

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