WO2004090196A1 - Surface-treated, zinc-plated steel sheet having excellent resistance to tape peeling, method for producing same, and surface treatment agent - Google Patents

Abstract

A surface-treated, zinc-plated steel sheet is disclosed in which at least a surface modification layer and a coating film are formed on a zinc-plating layer of a zinc-plated steel sheet. The surface modification layer contains, in terms of Si, 1-30 mg/m2 of SiO2, 0.5-15 mg/m2 of P and 0.4-10 mg/m2 of Al. The surface-treated, zinc-plated steel sheet is a non-chromate treated steel sheet, and particularly exhibits excellent resistance to tape peeling even after alkaline degreasing. A method for producing such a surface-treated, zinc-plated steel sheet and a surface treatment agent are also disclosed.

Description

 Description Surface treated zinc-based steel sheet with excellent tape peeling resistance, its manufacturing method, and surface treatment agent

 TECHNICAL FIELD The present invention relates to a zinc-coated steel sheet having a surface treatment, and in particular, does not contain any harmful hexavalent chromium on the zinc-based plating layer, and has particularly excellent tape-peeling resistance, and more or less after alkaline degreasing. The present invention relates to a zinc-based plated steel sheet having a surface treatment layer having excellent tape peeling resistance, a method for producing the same, and a surface treatment agent used for the surface treatment. Background art

 As steel sheets for home appliances, building materials, automobiles, etc., zinc-based steel sheets are being used from the viewpoint of corrosion resistance. However, zinc-based plating alone is not sufficient in corrosion resistance (whitening resistance) and it is difficult to secure adhesion to paint when used as a coating base. Has been done. When phosphoric acid consolidation is performed as a base treatment, the adhesion to the substrate is considerably improved, but the phosphoric acid lacks whiteness due to poor whiteness suppression effect.

 On the other hand, in the case of chromate treatment, although it has an excellent whitening suppression effect, it does not have close contact with I as it is. Therefore, in order to improve this and also to provide functions such as high corrosion resistance, anti-corrosion resistance and lubricity, a multifunctional product with a thin coating of about 1 xm on the chromate treatment layer was developed. It has been turned around by home appliance manufacturers. However, the use of harmful hexavalent chromium in chromate treatment has the problem of causing pollution, and in particular, in recent years, as awareness of environmental conservation has increased, the use of chromate treatment has tended to be avoided. Therefore, many surface treatment methods that do not use chromate (non-chromate) have been proposed and put into practical use.

For example, Japanese Patent Application Laid-Open No. 8-325570 describes a surface treating agent for a zinc-containing metal plated steel sheet using a mixed yarn of an aqueous resin and fine phenol carboxylic acid, and furthermore, the treating agent A surface-treated steel sheet having excellent corrosion resistance obtained by roll-coating the same on a metal plating surface has been disclosed. However, this fi is not a detachable component because the chromate treatment has been eliminated and the zinc-based plating layer is directly covered with an organic layer. In the case of surface-treated zinc-based steel sheets, alkali degreasing is performed to purify the oil applied to the surface with a press calorie, etc., in order to improve adhesion, etc. There was a problem that the corrosion resistance later deteriorated.

 As a solution to this problem, Japanese Patent Application Laid-Open No. 2000-144448 discloses that an organic film containing ion-exchanged silica is coated directly on a zinc-based plating steel sheet or lithium silicate. (4) An organic substrate is disclosed which is coated on a base treatment layer such as a phosphate layer and has improved corrosion resistance, corrosion resistance after alkali degreasing, adhesion, and the like.

 Japanese Patent Application Laid-Open Publication No. 2000-144444 discloses a zinc-based steel sheet, which is composed of a silicon oxide sol, a phosphoric acid compound, and a specific metal oxide or hydroxide in a suitable ratio. A surface-treated steel sheet having excellent corrosion resistance in which a chemical conversion treatment film having a predetermined thickness is formed by treating with an acidic treatment solution containing the acid treatment solution and then subjecting to a heat treatment. However, when inorganic treatment agents such as silica phosphate and metal hydroxide are applied, pinholes and the like are apt to be formed when they are used carefully. Corrosive liquid may enter through the holes, resulting in insufficient corrosion resistance. Therefore, according to the technique disclosed in this publication, an organic resin film or an organic composite silicate film is formed on the chemical conversion treatment film to improve the corrosion resistance and the coating property after the degreasing with an alkaline force.

 On the other hand, Japanese Patent Application Laid-Open No. 2000-12804600 discloses a zinc-based plating as a first layer and a mixed aqueous solution of a surface metal first phosphate and a metal oxide sol as a second layer. · A surface-treated steel sheet with improved corrosion resistance and ^ ¾-adhesion by forming an organic layer as the third layer and forming an organic layer as the third layer is disclosed.

Also Japanese Patent 2 0 0 1 1 1 6 4 5 discloses, on the surface of the zinc-based plated steel sheet, as the first layer, the predetermined thickness of the composite consisting of S I_〇 ₂ particles and phosphoric acid compound By forming an oxide film and then forming an organic male of a predetermined thickness based on an organic polymer having OH or COOH groups as a base resin, corrosion resistance, corrosion resistance after alkali degreasing, and release properties To An improved organic coated steel sheet is disclosed.

 Further, Japanese Patent Application Laid-Open No. 2003-293151 discloses a non-chromate type steel sheet having a surface-modified layer containing A1, Si, and P at a specific ratio, and a chromate-treated steel sheet. A surface-treated zinc-based steel sheet having the same corrosion resistance as described above is disclosed.

 As described above, for non-chromate treatment, various improvement techniques have been proposed for some issues, and various performance improvements have been made. However, according to the recent experience of the present inventors, even a zinc-based plated steel sheet subjected to an improved non-chromate treatment has a serious problem that it does not have a tape peeling resistance. Has clearly emerged.

 In other words, the surface-treated steel sheet is shipped with the band end plate rolled and used by the customer as a cutting plate after rewinding the coil. At this time, the remaining end of the coil is felhed with adhesive tape. May be stored. Cut plates are processed into AV product cases and parts through stamping, lubricating, press calories, and de-alkali processes.At that time, the part numbers, sizes, grades, etc. are printed on the surfaces of the cases and parts. The displayed adhesive label may be affixed for the purpose of (Sit. The tape peeling means that when the customer peels off the above adhesive tape or adhesive label, the top coating film on the surface of the system is coated together with the tape. The phenomenon of peeling from the surface is a very important issue in the quality of surface-treated steel sheet, and when it occurs, it becomes a serious product defect.

 This tape peeling hardly occurs on the conventional chromatized surface treated steel sheet with a thin film coating on the upper layer, and therefore, the tape peelability has been improved to prevent tape peeling. " , Was not recognized.

However, as the inventors of the present invention proceeded with the improvement study on the non-chromate zinc-based steel sheet, it was found that the non-chromate-treated surface-treated steel sheet suffers from the above-mentioned good and poor tape peeling resistance. Have been. In particular, it is evident that this is likely to occur when stored for a long period of time with an adhesive tape or label on the surface, or when stored under high S ^ humidity conditions for transportation, etc. It has been found that "peelability" is one of the extremely important product characteristics. However, under the situation where the problem of “tape peeling” itself is hardly recognized, there is no room for problems such as “improvement of tape peeling resistance”. It is not enough to have already disclosed the metal-plated steel sheet, and as a matter of course, no specific method has been developed.

 The present invention has been made in view of the above circumstances, and is directed to a non-chromate treated surface-treated zinc-coated steel sheet, which has particularly excellent tape peeling resistance, and particularly excellent tape peeling resistance after alkali degreasing. The task was to provide a surface-treated zinc-based steel sheet and a method for producing the same, and to provide a surface treatment agent useful for this treatment. Disclosure of the invention

Means for Solving the Problems The present invention which can solve the above-mentioned problems is a surface-treated zinc-based steel sheet having at least a surface-modified layer and an overcoat film formed on a zinc-based steel layer in a »-based steel sheet, the surface modification layer is a 1-3 01118 /] 1 ² 3 I_〇 ₂ S i terms, 0. 5 to 1 5 mg / m ² of P and 0. 4~: LO mg / m ² A surface-treated Sffi-leaded steel sheet with excellent tape peeling resistance that contains A1 as a fiber.

Further, the surface treating agent of the present invention is a Si ₂ -containing phosphoric acid-based surface treating agent useful for obtaining the above zinc-based steel sheet having excellent strippability, and has a solid content of 0.0. 1 to 14.5% (mean% by mass; the same applies hereinafter). The amount of Si, P, and A1 contained in this treatment agent and the yarn ratio (mass ratio) are as follows:

 S i: 0.02 to 4.5%

 P: 0.000 0 5 to 1.5%

 A 1: 0.000 0 1 to 0.5%

 1.5≤S i / P≤6 0, 4.5≤S i / A l≤2 3 0

Where there is.

In the invention according to the $ ¾t method of the present invention, after forming a surface treatment agent layer on a surface of a zinc-based steel plate with a surface treatment agent satisfying the above requirements, the surface treatment agent layer is washed, and excess surface treatment from the surface treatment agent layer is performed. Perform P and _ or A1 and then form a surface modified layer by difficulty. And features. BRIEF DESCRIPTION OF THE FIGURES

 Fig. 1 shows the FT-IR spectrum of the surface modified layer of Experiment No. 38 to simulate, and Fig. 2 shows the FT-IR spectrum of the surface modified layer of Experiment No. 52 described later. Is the FT-IR spectrum of sodium polyacrylate. BEST MODE FOR CARRYING OUT THE INVENTION

 The surface treated SM lead-based steel sheet of the present invention is an invention on the premise that it has a surface-modified layer formed by a non-chromate-based treating agent. Examples of the zinc-based plated steel sheet to which the present invention is itffl include zinc MS plated steel sheet, and all! E-based alloy plated steel sheets such as zinc-Ni, »—Fe,» —A1, and the like. As the method, any of a melting plating method, an electric plating method, and a vapor deposition plating method can be employed.

The present invention relates to a non-chromate treatment, a new solution to the problem of the present inventors in the field of non-chromate treatment steel plate, and a means for enhancing “tape peeling resistance”. Then, in terms of Si, 1 to 3 O mgZm ² Si 0 ₂ and 0.5 to 15 m 8/111 ² ? It has the greatest feature in that the inclusion of A 1 of Oyobi 0. 4~1 O mgZm ^2.

 In the present invention, “tape peeling resistance” refers to, as described above, a method in which an adhesive label or an adhesive tape is attached to a surface-treated zinc-based steel sheet and left to stand. The degree of tape peeling resistance is determined by the type of adhesive tape used in the tape peeling test, especially the adhesive strength of the adhesive and the solvent contained in the tape. It depends on the type, such as the number and type. .

The reason for the peeling of the top coat and the surface-modified layer due to tape peeling is that the solvent and visible ij contained in the adhesive tape's viscosity may cause the top coat to be formed on the surface-modified layer or on top of it. It diffuses to the surface of the zinc-based plating layer through the sword, and it is thought that the bonding strength is reduced due to the burning of the fuel at the bonding interface. This is because the tape peeling resistance seems to vary considerably depending on the type and content of j.

However, even if there are slight differences in the types and amounts of solvents and plasticizers, etc., which are compounded as adhesives in ordinary adhesive tapes, their diffusion, particularly to the SiO ₂ -containing layer, has an extreme Since there seems to be no difference, in the present invention, as shown in the examples below, as a tentative evaluation criterion, “filion tape manufactured by Sliontec Co., Ltd.“ No. # 950 ”” and “Nichibanne Cellophane” The tape ("Cellophane Tape" is a trademark) was evaluated as a representative example in terms of the peelability of the tape when selected and used.

The main component comprising silica of the surface modified layer of the present invention (S i 0 _2), an example co Roidarushirika or silicon oxide coming included derived from salts, these silica force Since it is essentially an inorganic material and has a good affinity for the ¾-based plating layer, it can be used as an underlayer for the overcoat to separate the zinc-based plating layer from the overcoat. Demonstrate the effect of increasing.

As described above, one of the causes of the tape peeling is that the diffusion force of a solvent such as an adhesive tape or the like included in the viscosity I or the like and the diffusion component such as visible ij move to reduce the bonding strength at the interface between the layers. It is thought that it is lowering. However, the silica contained as a main component in the surface modified layer of the present invention exerts an excellent barrier effect on the solvent ゃ awake IJ and the like diffused and observed from the overcoating ^ IU1. It is considered that it exerts the function of preventing intrusion in the direction or diffusion at the interface of the overcoated surface and the surface modified layer. Therefore, if a surface-modified layer containing an appropriate amount of silica is formed, the tape peeling resistance is dramatically improved. The present inventors pursued a quantitative relationship for effectively exerting such an effect of improving the tape peeling resistance of silica, and found that the silica content in the surface-modified layer was 1 to 30 mg in terms of Si. / m by ² range (2. 1 4~6 4. 3 S i 0 2 of MgZm ²⁾ to tone ST Rukoto, the resistance to tape peeling resistance excellence in is exhibited is I certified.

If it is less than l mgZm ² silica content of S i buy, becomes insufficient functions as a barrier layer described above,耐Teichipu peelable satisfactory hardly be exhibited. Therefore, the silica content in the surface modified layer needs to be 1 mg / m ² or more in terms of Si. The lower limit of silica content is S It is preferably 2 mgZm ^{2 in} terms of i, and a more preferred lower limit is 2.5 mgZm ² .

And, as the silicic acid content increases, the function as the above-mentioned parier layer increases, but when the silica content further increases, the tape peeling resistance tends to decrease. I think the reason is as follows. In other words, the silica in the surface modified layer exists as an aggregate of fine particles while the amount is small, but it is considered that the fine particles will be in a multi-layered state when the amount of silica is large. Since the bonding force between the silica microparticle layers in such a multi-layered state is not always strong, the force is applied to the silica microparticle layer in the multi-layered state in the direction of peeling off the tape, and the silica is applied in the direction of peeling. It is considered that the fine particle layer causes delamination. In order to minimize the delamination due to shear fracture of the surface-modified layer itself, the silica content in the surface-modified layer should be suppressed to 3 O mg / m ² or less in terms of Si. When the silica content in the surface modified layer exceeds this upper limit, the tape peeling resistance clearly shows a tendency to decrease. It should be noted that an excessively high silica content in the surface-modified layer would be economically useless, and in this respect, a preferable upper limit is 15 mgZm ^{2 in} terms of Si, and a more preferable upper limit is 10 mgZm ^2. The most preferred upper limit is 8 mgZm ² .

 The silica-containing surface modified layer of the present invention also includes P and A1. In order to form the surface-modified layer, it is preferable to etch the surface of the zinc-based plating layer to deposit fine particles of colloidal force derived from colloidal silica force on the surface of the appropriately roughened plating layer. As the etching component, for example, sulfuric acid, sulfuric acid, food, phosphoric acid, and the like can be used. Particularly preferred as the etching component are phosphoric acid, biphosphoric acid, phosphorous acid, and phosphorous acid. This method uses an aluminum salt such as an acid (hereinafter simply referred to as aluminum phosphate compound), and uses an acidic aqueous liquid in which the colloidal sily power of it * is dispersed as a surface modifier. For this reason, the resulting surface-modified layer contains P and A1.

When an acid solution containing colloidal silica and an aluminum phosphate compound is used as a surface treatment agent, the surface of the zinc-based plating layer is etched while the acidic aqueous solution etches the phosphoric acid on the surface of the zinc-based plating layer. Hardly soluble in ice or aluminum A 1 P_〇 ₄ and A l ₂ (HP_〇 ₄₎ 3 principal reaction layer slightly soluble) in solution (surface-modified layer) is formed. By depositing and incorporating the silica fine particles into the reaction layer, the aluminum phosphate and the silica fine particles are combined and integrated. In addition, a dense reaction layer is formed between the zinc-based plating layer roughened by etching, and the bond with the overcoat formed on this reaction layer is also dense and solid. Therefore, the tape peeling resistance is significantly improved. Further, as described later, when the aqueous solution of the organic resin is contained in the acidic aqueous solution, the deposition state of the silicide fine particles in the obtained surface-modified layer can be further strengthened. Reaction layer phosphorus輯aluminum and silica force fine particles are combined integrally composed mainly of A 1 P 0 ₄ and _{A 1 2 (HP 0 4)} 3 of the sparingly soluble, for example, were obtained using nitric acid as an etchant surface Since it has better alkali resistance than the modified layer, it exhibits excellent performance in tape peeling resistance after alkali degreasing. However, when the silicic acid-containing surface modified layer is formed using the above aluminum phosphate compound as an etching component, depending on the respective contents of P and A1 contained in the surface modified layer, the resistance of the surface modified layer may be reduced. It was found that there was a difference in the tape peeling resistance after alkaline and alkaline degreasing. In particular, as the surface-modified layer became thicker and the amount of aluminum phosphate in the layer increased, the tape peeling resistance after alkali degreasing tended to decrease.

When the surface modification layer is thin, M¾ since close to the surface modified layer and the zinc plated layer, zinc is eluted by zinc main luck layer is etched, the H + is H ₂ gas in the treatment agent Therefore, the pH near the surface modification layer close to the plating layer rises, and the pH tends to be alkaline. Thus p H raised under a large atmosphere A 1 P 0 ₄ and _{A l 2 (HP O 4)} 3 number generated, the reaction layer in which these sparingly soluble aluminum phosphate and silica fine particles are turned into integral composite is formed The tape peeling resistance is 1 ', and the tape peeling resistance after alkali degreasing I is greatly improved. When the surface-modified layer becomes thicker, the surface of the surface-modified layer being formed is farther away from the plating layer, so the pH of the surface is affected by zinc dissolution due to dissolution of zinc. Oyobi hardly a connexion, Table ®¾ electrolyte layer than the ambient surface treatment agent original acidic near the surface of the easily soluble in water than the difficultly soluble a 1 P 0 ₄ of and _{a 1 2 (ΉΡ 0 4)} 3 (Easily subject to alkali attack) Al (H ₂ P 0J ₃ is easily formed. This water-soluble A 1 When (H ₂ P0 _{4) 3} is present more in the outermost layer of the surface-modifying layer, since the water-soluble component can and eroded in alkali will be released from the surface modified layer, by connexion surface this It is considered that the alkali resistance of the modified layer is reduced and the tape peeling resistance I after degreasing is reduced.

However, in the present invention, by setting the thickness of the surface-modified layer in a specific range so as to achieve the above, and by setting the amounts of P and A1 in the layer to a specific range, stable and excellent tape-peeling resistance and excellent performance can be obtained. The tape peeling resistance after luke degrease was able to be secured. Therefore, in the present invention, it is necessary to control the P content in the surface-modified layer to be in the range of 0.5 to 5 mg / m ^{2 and} the A 1 content in the range of 0.4 to 10 mg / m ^2. is there. Less P content is 0. 5mgZm ^2, the A1 content is less than 0. 4mgZm ^2, and the etching action mosquitoes坏足, on a dense reaction layer is not easily formed by it, resistance to tape peeling resistance improvement by deposition promoting Siri force microparticles Effectiveness may not be fully exhibited. A more preferred lower limit of the P content is 0.6 mgZm ² , and a more preferred lower limit of the A 1 content is 0.5 mgZm ² . Further, when the P content and A 1 content is excessively large, now _{A 1 (H 2 P0 4)} 3 alkali resistance shortage is included in the surface-modified layer as described above, eroded alkali Eluted from the surface modified layer. A preferred upper limit of the P content is 9 mgZm ² , a more preferred upper limit is 7.2 mgZm ² , and a most preferred upper limit is 5 mgZm ² . A preferred upper limit of the A1 content is 8 mgZm ² , a more preferred upper limit is 6.3 mgZm ² , and a most preferred upper limit is 4.4 mgZm ² .

 Furthermore, the ratio of each content of Si, P, and A1 contained in the surface modified layer is determined by the relationship of the following equations (1) and (2).

 0.5≤S i / P≤20 …… (1)

 0.7 ≤P / A1≤6 …… (2)

If it satisfies, it is possible to ensure more excellent tape peeling resistance I 'and raw tape peeling resistance after degreasing.

If the above-mentioned SiZP is less than 0.5, the ratio of Si 表面₂ in the surface-modified layer tends to be relatively insufficient, so that the tape peeling resistance tends to decrease. Conversely, if this ratio exceeds 20, It will be quantifying坏足aluminum phosphate as compared with the silica content, the effect of A l PO ₄ and _{A l 2 (HP 0 4)} 3 of poorly soluble is hardly effectively exerted. From such a viewpoint, the lower limit of the more preferable ratio of S i / P in the surface modified layer is 1. A more preferred upper limit is 15 and a still more preferred upper limit is 10.

If P / A 1 in the above formula (2) is less than 0.7, the tape peeling resistance tends to decrease due to etching feet caused by phosphoric acid deficiency. If this ratio is too high no longer opposite to exceed 6, the formation of the etching process A 1 sparingly soluble formed after P 0 ₄ and A 1 ₂ (HPO ₄₎ the amount of ₃ is reduced dense reaction layer Insufficient, and the effect of improving the tape peeling resistance after alkali degreasing is reduced. Therefore, by setting PZA 1 to 0.7 or more and 6 or less, it is possible to form a sufficient amount of the reaction layer by promoting the formation of hardly soluble aluminum phosphate while securing the etching effect of the above. More preferably, the lower limit of P / A 1 is 1, and the upper limit is 4.

 In addition, in the adjustment of S i / P and PZA 1, the content of silica, silicate, phosphoric acid component and A 1 component in the surface treatment agent is adjusted, and a surface modified layer is formed so as to be key. At this time, it may be adjusted by washing with water and washing the inverted phosphoric acid component and the A1 component. Also, the amounts of Si, P, and Al in the surface modified layer may be, for example, fluorescent X It can be confirmed by the line method.

The surface obtained by not only containing silica in the surface modified layer, but also including a specific amount of P and A1 and controlling the content ratio of Si, P and A1 within the ¾Ε range The modified layer becomes more dense without pinhole defects, etc., and exhibits excellent performance not only in tape peeling resistance under dry conditions but also in tape peeling resistance after degreasing. In the present invention, the surface modification layer may further contain an organic resin. The organic aspect is that when forming the surface-modified layer, silica fine particles are firmly deposited in the surface-modified layer to improve the tape releasability, and further the releasability after alkali degreasing. This is because it has the effect of further improving. The organic resin is not particularly limited, and examples thereof include an acryl-based resin, a melamine resin, a phenol resin, an epoxy resin, a urethane resin, a polyester resin, an alkyd resin, and a polyolefin resin. , Or, two or more kinds can be used in combination.

 Among these organic resins, it is preferable to use a water-soluble organic resin, and it is particularly preferable to use an organic resin composed of an organic acid. As an organic resin composed of an organic acid, poly (meth) acrylic acid is crucial, and a resin obtained by neutralizing a part of acid groups or ^^ with a base may be used. As described above, when forming the surface-modified layer, it is preferable to etch the base plating layer using an acidic aqueous solution, but the organic resin containing an organic acid as a constituent is mainly water-soluble. Since the aqueous liquid containing such organic tree] ^ becomes acidic, it is excellent in stability and workability when blended into the above acidic aqueous liquid. When poly (meth) acrylic acid is used, the weight average preferable amount is preferably 2000 or more. It is more preferably at least 100,000, still more preferably at least 1,000. As a base when using a salt of an organic resin composed of an organic acid, ammonia, hydroxide of an alkali metal such as τ-sodium oxide, hydroxylated lime or the like can be used. The organic resin in the surface-modified layer can be analyzed by, for example, listening to the surface-modified layer by FT-IR to determine the structure of the organic resin (ester bond, carboxyl group, ketone, amino group, hydroxyl group, and carbon 7_K FT-IR peaks originating in the spectrum appear in the spectrum, and their presence can be awakened. In the present invention, it is preferable that the organic leakage is present so that the absorption SS of F-IR derived from the structure of the organic resin is 0.1 to 15. The FT-IR absorption bow is an indicator of the content of the organic resin in the surface-modified layer. By setting the FT-IR absorption intensity within a certain range, the tape peeling resistance and the Al force are reduced. The tape peeling resistance after regreasing can be improved.

 The present invention also includes a surface treating agent used for forming the surface modified layer. This surface treatment agent is a phosphoric acid treatment agent in the form of a solution containing fine silica powder such as colloidal silicide. The solid concentration is set to 0.01 to 14.5% by mass, Requirements for i, P, A1 amount (mass%, hereinafter simply referred to as%) and composition ratio (mass ratio)

 S i: 0.02 to 4.5%

 P: 0.000 0 5 to 1.5%

A1: 0.00 0:! To 0.5% 1.5 ≤ S i / P ≤ 60, 4.5 ≤ S i / A 1 ≤ 230

The ability to adjust to meet

 If the solid content of the surface treatment agent is less than 0.01%, it is difficult to form a surface modification layer having a satisfactory thickness in one treatment, and many treatments are required. However, if the concentration is excessively high, exceeding 14.5%, solids are likely to be formed at the gas-liquid interface in the processing agent, and product defects such as press flaws and bumps are likely to occur. Tend to occur. Taking these points into consideration, the more preferable solid content ^ J is 0.05% or more and 10% or less, and more preferably 0.1% or more and 5% or less.

If the S content in the surface treatment agent is less than 0.002%, the silica content in the surface modified layer, which is the main component of the barrier layer, tends to be low, and satisfactory tape peeling resistance cannot be obtained. On the other hand, if SS¾ exceeds 4.5%, the content of silica in the surface treatment agent becomes excessively high, and the silicic acid content in the surface-modifying layer becomes excessive, and the tape peeling resistance tends to decrease. Will be shown. Based on this tendency, the lower limit of S ll in the surface treatment agent is preferably 0.01%, and more preferably 0.03%. A more preferred upper limit is 4%, and a still more preferred upper limit is 3%. The content of Si in the surface treatment agent may be adjusted according to the content of Si ₂ mainly mixed as colloidal silica or the like, and further, the amount of silicate or the like.

Here, examples of the colloidal silica that can be blended with the surface treatment agent as a source of silicic acid include, for example, “0”, “OS”, and “OS” of the “Soso-Tex” series (Nissan Chemical Industries, Ltd.) "OL", "OXS", and "OUP" is preferably, as a _{silicate, Na 4 S i0 4 Na 2} S i0 3 are preferable.

On the other hand, the amount of P in the surface treatment agent depends on the amount of the phosphoric acid compound compounded as phosphoric acid, biphosphoric acid, phosphorous acid, phosphoric acid, etc., and mainly affects the etching effect and the dense reaction layer. It is an important factor that governs formability. If the old age is too low, the etching effect will be insufficient, and the formation of the dense aluminum phosphate-based reaction layer described above will also be insufficient, and the effect of accelerating the deposition of silica fine particles will be reduced. (4) Al-resistance tends to be insufficient. Therefore, the P concentration in the treating agent is preferably 0.0005% or more. >> A more preferred lower limit is 0.001% and a still more preferred lower limit is 0.01%. However, if the P-Ut in the surface treatment agent is excessively high, it will be difficult to control the amount of etching of the zinc-based plating surface, and the product will tend to have poor appearance.

■ There is also a problem in actual operation, such as corrosion of the components, etc., so it is preferable to set the content to 1.5% or less. A more preferred upper limit is 1%, and a still more preferred upper limit is 0.5%. The amount of A 1 in the surface treatment agent mainly depends on the amount of aluminum salts such as phosphoric acid, and also the amount of hydroxides of A 1 that may be added as necessary. It is a source of hardly soluble aluminum phosphate, which forms as a dense reaction layer in the process, and plays an important role in promoting the deposition of silica and improving the adhesion and resistance to surface tension of the surface modified layer. In order to exert such an effect effectively, the A1 concentration in the treating agent should be at least 0.00001%, preferably at least 0.005%, more preferably at least 0.001. It is better to adjust to more than%. However, if A 1 is excessively high, solids are likely to be formed at the gas-liquid interface in the processing solution, and product defects such as push flaws and bubbles are likely to occur. Therefore, the content is reduced to 0.5% or less. A more preferred upper limit is 0.4%, and a still more preferred upper limit is 0.2%.

 S i / P and S i / A 1 in the surface treatment agent affect the amount of the aluminum phosphate-based dense reaction layer generated in the early stage of the surface treatment and the amount of the sily force, When the P content including the P content is added to the Si content, the etching becomes relatively insufficient, so that not only the density and the production amount of the reaction layer mainly made of aluminum phosphate are sufficient, but also the die force is increased. There is a possibility that the effect of depositing on the adhesive will also be reduced, and that the tape peeling resistance and the tape peeling resistance after the tread will be sufficient. Conversely, if the P content or A1 content becomes excessively high with respect to the Si content, silica in the three-reactive layer will be adversely affected. ! ^ There is a possibility that the clay will be slightly clogged and the tape peeling resistance will be sufficient.

From these viewpoints, the Si ZP contained in the surface treatment agent is preferably 1.5 or more and 60 or less, more preferably 1.8 or more and 20 or less. S i / A l is preferably 4.5 or more and 230 or less, more preferably 6 or more and 100 or less. The method for adjusting the content of Si, P, and A1 in the surface treatment agent for undercoat to the above-described preferred range is not particularly limited, but the content of silica, silicate, and the like in the surface treatment agent for Si content. In addition, the P content depends on the content of phosphoric acid phosphate and the like in the treating agent, and the A1 content depends on the content of phosphate and hydroxide of A1 in the treating agent. Therefore, it may be performed by directly controlling the content of these components in the surface treatment agent.

 When the surface treating agent contains the above-mentioned organic resin, it is preferable that the addition of the organic resin in the surface treating agent is 0.1 to 3 gZl in terms of the solid content of the organic resin. When the addition concentration is less than 0.0 l gZl, the effect of adding the organic resin is hardly exhibited, and when the addition concentration is more than 3 g, 1, the tape peeling resistance after alkali appearance is deteriorated. May do so.

 In the present invention, colloidal silica, an aluminum salt compound such as phosphoric acid, biphosphoric acid, phosphorous acid, or biphosphorous acid, and an organic resin (preferably poly (meth) acrylic) are particularly preferable as the surface treatment agent. An acidic aqueous solution containing an acid or its acid.If this surface treatment agent is used, as described above, the zinc on the steel plate surface is etched under the acid 'I' A dense reaction layer mainly composed of hardly soluble aluminum phosphate was formed on the surface of the system plating layer, silica was deposited in the reaction layer, and the action of the organic resin was surely taken into the reaction layer. A dense reaction layer is formed between the layer and zinc, and it becomes a surface-modified layer that exhibits excellent tape peeling resistance and tape peeling resistance after degreasing with an I-force.

■ More specifically, in 100% of the surface treatment agent, the solid content of each component is as follows: phosphoric acid, phosphoric acid, phosphorous acid, phosphorous acid, biphosphorous acid) A 1; 0.05 to 5.0 (more preferably 0.01 to L. 0)%, colloidal silica; 0.004 to 10 (more preferably 0.05 to 3)%, A preferred form is an acidic aqueous liquid containing! To 3 gZl and having a pH in the range of 1.5 to 4.0. This is because the composition of the surface-modified layer can be adjusted to the above-mentioned range by adjusting the yarn of the surface-treating agent to these ranges, and preferably by washing with water or the like.

Methods for treating zinc-based steel sheets with the above surface treatment agents include dipping and spray coating. Coating method such as construction method and mouth coating method can be adopted. In the case of the immersion method, it is preferable to immerse approximately 0.1 to: L 0 seconds or so. The spray coating method is a more preferable method for making the reaction with the system plating difficult, and the preferable spray pressure at that time is 20 to 500 kPa (about 0.2 to 5.0 kgf / cm ² ), the preferred display time is in the range of 0.1 to 10 seconds.

After the surface treatment agent layer is subjected to surface treatment with the above-mentioned surface treatment agent to form a surface treatment agent layer (ice washing, which is a layer that becomes a surface modification layer), the soluble component is removed by washing with water. [5 iron is preferred. Thereafter, the surface is modified by heating to, for example, about 30 to 150 ° C. to make the water difficult to obtain. The water washing at this time is an important treatment step for improving particularly the alkali resistance of the finally obtained surface-modified layer, and also the tape peeling resistance after alkali degreasing. That is, the present inventors have confirmed in various experiments that, in the case of a surface-modified layer which has been treated with the above-mentioned surface treating agent and then directly baked or baked, P There is often content and a 1 content greater than preferred P content 0. 5~ 1 5 mg Zm ² and preferred a 1 content 0. 4~ 1 0 mgZm ² before mentioned surface modification layer, after alkali degreasing It was confirmed that it was difficult to secure the tape peeling resistance of the tape.

In other words, as explained earlier in the Wei-Fe section, by treating the surface of a zinc-based steel sheet with a treating agent containing fine silica particles and an aluminum phosphate salt, the corrosion resistance of the zinc-based steel sheet and the post-degreasing property The method itself for improving corrosion resistance is π, and it has been confirmed that this surface treatment is effective as a base treatment to enhance the adhesion of organic overcoats. However, the inventors of the present invention have recognized that, including the patent of faki, the surface-modified layer formed by the above-mentioned surface treatment agent containing fine silica particles and aluminum phosphate is considerably modified. contains a large amount of aluminum phosphate component, the amount is, for example, P conversion calculated at 3 O mgZm ² about above, it was found that in some cases as high as 1 5 mgZm ² about more than a 1 terms. And, when these P and A1 contents are high, they have a considerable adverse effect on the tape peeling resistance, especially after alkaline degreasing, and also reduce these P and A1 contents to the above-mentioned acceptable range, In addition, it is hardly soluble (excellent in alkali resistance) and dense In order to obtain a surface-modified layer, a water treatment is performed after the underlayer surface treatment, and a water-soluble component of the aluminum phosphate contained in the surface treatment agent layer (mainly A 1 (H ₂ PO ₄ It was found that it was convenient and desirable to elute ₃ ) in advance.

The rinsing method may be an immersion method or a spray method, and the rinsing conditions may be changed according to the content of the water-soluble component in the phosphate aluminum component contained in the surface treatment agent layer. The washing time should be about 0.5 to 15 seconds, and in the case of the spray method, the washing time should be about 0.5 to 15 seconds and the spray pressure should be about 20 to 500 kPa (about 0.2 to 5 kgi, cm ² ). It is preferable to use the water-soluble component more efficiently.

Although the lower limit of the amount of the surface modified layer deposited on the zinc-based steel sheet is not particularly limited, it is preferable that the dry coating after the water washing treatment be 4.2 mgZm ² or more. If the amount is too small, it becomes difficult to uniformly cover the surface of the zinc-based plating, so that the peeling force tends to be low. The lower limit of the adhesion amount is more preferably 7 mg / m ² , and even more preferably 8 mg Zm ² . However, while conversely if too large, as described above, phosphorus Sana Rumi two © beam is poorly soluble Al P0 ₄ or Al ₂ (HP_〇 ₄₎ to produce the surface modified layer soluble ₃ in water a on going turned into _{1 (H 2 P0 4) 3} , compactness of the reaction layer by etching the lack of zinc plated surface becomes slightly descending T, resistance to tape peeling resistance after alkaline degreasing indicates the degradation tendency. connexion, the total adhesion amount of the surface modification layer 13 OmgZm ² or less and it is preferable to. adhesion amount of the upper limit is more preferably 65MgZm ^2, more preferably 5 OmgZm ^2, and most preferably 37m g / m ^2. Note The total adhesion amount of the surface modified layer is determined by, for example, X-ray fluorescence analysis, etc. Perform quantitative, these adhesion amount, assuming that S I_〇 _{2, A1P0 4, Zn 3 (} P0 4) 2, A 1 2 0 3 is produced in the reforming layer, is calculated When the standard of the preferable range of the adhesion amount of the surface modified layer is represented by the thickness, it is 0.0021 to 0.0657 m when the specific gravity is 2.

The surface-treated zinc-based steel sheet of the present invention has the above-mentioned one-dimensional surface-modified layer of the present invention formed thereon. Through the layers, properties such as corrosion resistance, emblem resistance, workability, and adhesion are improved or improved. For example, epoxy-based resin, acrylic resin, polyamide-based resin, polyester-based resin, alkyd-based resin, urethane-based resin, polyethylene-based resin, silicon-based resin, fluorine-based lining, various types of organic overcoats with aminoplast-based shelves Are layered.

 Above all, a surface-treated steel sheet having a configuration provided with a resin film formed from a specific emulsion composition as an overcoat is preferable. Emulsion pirates used for forming this resin film (overcoating skin II) are mainly composed of ethylene-non-carboxylic acid copolymer (including neutralized state) and ethylene-unsaturated carboxylic acid copolymer. Amine having a boiling point of 100 ° C or less, equivalent to 0.2 to 0.8 mol (20 to 80 mol%) per mol of ropoxyl group, and ethylene-free! ^-Carboxylic acid 0.02 to 0.4 moles per mole of carboxyl groups of the copolymer (including 2 to 40 moles of monovalent metal compound and capable of reacting with lipoxyl groups A crane having two or more functional groups (I contains 0.5 to 20% by mass with respect to 100% by mass of the solid content of the emulsion fiber, and amines and ammonia having a boiling point of more than 100 ° C are substantially Not included.

 The resin obtained from the emulsion composition is excellent in various properties such as paintability, lubricity, erosion, and grounding property, and also has good corrosion resistance after the degreasing step and a good performance. It is also excellent in releasability, and these findings have already been filed in the present invention as Japanese Patent Application No. 2004-302231.

 The ethylene-unsaturated carboxylic acid copolymer is a copolymer of ethylene and an unsaturated carboxylic acid such as (meth) acrylic acid. A copolymer can be obtained by polymerizing with a known high-temperature high-BEfi compound. The copolymer is most preferably random, but may be a block copolymer or a copolymer in which an unsaturated carboxylic acid moiety is grafted. An olefin monomer such as propylene or 1-butene may be used instead of a part of ethylene, and another vinyl monomer of Π may be partially copolymerized (1) as long as the object of the present invention is not impaired. 0% by mass or less). Unsaturation Power to Ethylene The copolymerization ratio of rubonic acid is preferably 10 to 40% by mass based on 100% by mass of monomer.

Since the above-mentioned ethylene-unsaturated carboxylic acid copolymer has a hydroxyl group, Neutralization with a ¾ group or a metal ion enables emulgyonyi (water dispersion). At this time, an amine having a boiling point of 100 ° C. or less is used as the organic base. Amines having a boiling point of more than 10 o ° c remain on the steel sheet when the fiber is fiberized and immediately increase the water absorption of the overcoating film, resulting in lower corrosion resistance and lower tape peeling resistance. . Therefore, the emulsion pirates used for forming the overcoat film do not include amines having a boiling point of more than 100 ° C. In addition, ammonia was not included because the effect of adding ammonia was not recognized. Note that the above boiling point reverses the boiling point under large ^ ffi.

 Specific examples of amines having a boiling point of 10 ° C or lower (hereinafter, referred to as the above amines) include triethylamine, N, N-dimethylbutylamine, N, N-dimethylarylamine, N-methylpyrrolidine, and tetramethylamine. Tertiary amines such as methyldiaminomethane and trimethylamine; secondary amines such as N-methylethylamine, disopropylamine, and getylamine; propylamine, t-butylamine, sec-butylamine, isoptylamine, 1 And primary amines such as 2,2-dibutylpropylamine and 3-pentylamine. These can be used alone or in combination of two or more. Of these, tertiary amines are preferred, and most preferred is triethylamine.

The amount of the above amines is in the range of 0.2 to 0.8 mol (20 to 80 mol%) based on 1 mol of the lipoxyl group in the ethylene-unsubstituted carboxylic acid copolymer. This is because if it is in this range, the corrosion resistance and the tape peeling resistance are good. When the amount of the above amines is less than 0.2 mol, the particle size of the observer in the emulsion becomes large and the above-mentioned effect is not exerted.However, when the amount exceeds 0.8 mol, the emulsion becomes thickened. It is not preferable because it may gel. A more preferred upper limit of the amount of the amines is 0.6 mol, more preferably 0.5 mol, and a more preferred lower limit of the amount of the amines is 0.3 mol. For preparing the emulsion composition, a monovalent metal ion is also used. It is effective in improving solvent resistance. The monovalent metal compound preferably contains one or more metals selected from sodium, potassium and lithium, and is preferably a hydroxide, carbonate or oxide of these metals. Among them, NaOH, KOH, LiOH and the like are preferable, and Na〇H is preferable because it has the best performance. Conversion of divalent or higher valent metals The compound is not used because the effect of adding it is not recognized.

 The amount of the monovalent metal compound is in the range of 0.02 to 0.4 mol (2 to 40 mol%) based on 1 mol of the hydroxyl group in the ethylene-unsaturated carboxylic acid polymer. And When the amount of the metal compound is less than 0.02 mol, the emulsification stability is sufficient. However, when the amount exceeds 0.4 mol, the hygroscopicity (particularly with respect to the alkaline solution) of the obtained resin male increases, Corrosion resistance after the degreasing step is not preferable because the tape peeling resistance deteriorates. A more preferred lower limit of the amount of the metal compound is 0.03 mol, a still more preferred lower limit is 0.1 mol, and a more preferred upper limit of the amount of the metal compound is 0.5 mol, and a still more preferred upper limit is 0.2 mol. is there.

 The preferred ranges of the amounts of the amines and the monovalent metal compounds used are as described above, but all of them are obtained by neutralizing the carboxyl group in the ethylene-unsaturated carboxylic acid copolymer. Used for emulsification. Therefore, if the total amount (neutralization amount) of these is too large, the emulsion yarn! In addition to the fact that the viscosity of the product may rise rapidly and solidify, the reversible alkali content causes deterioration of the corrosion resistance, and thus requires a large amount of energy for volatilization. However, if the amount of neutralization is too small, the emulsifiability is inferior. Therefore, the total amount of the amines and the monovalent metal compound used is in the range of 0.3 to 1.0 mol based on 1 mol of the hydroxyl group in the ethylene-non-carboxylic acid copolymer. It is preferable to set the range.

 In the neutralization process (emulsification process) of the ethylene-monoperoxycarboxylic acid copolymer with the amines and monovalent metal ions, the amine having a boiling point of 100 ° C or less and the compound of a monovalent metal are generally used. It is preferable to add the copolymer to the copolymer at the same time, or to add the amine having a boiling point of 100 ° C or lower first. The reason is not clear, but if amine having a boiling point of 100 ° C. or less is added later, the effect of improving the flexibility and the tape peeling resistance may be insufficient.

A crane U having two or more functional groups capable of reacting with a hydroxyl group is combined with the emulsion composition. Chemically cross-link the above ethylene-peroxycarboxylic acid copolymer, and peel! This is to improve fish quality. The amount of the crosslinking agent is 1 to 20% by mass (more preferably 5 to 0% by mass) of 100% by mass of the solid content in the emulsion composition. One If the amount is less than 10% by mass, the effect of crosslinking by chemical bonding is sufficient, and the effect of improving corrosion resistance and tape peeling resistance is hardly exhibited. On the other hand, if the content is more than 20% by mass, the crosslink density of the resin film becomes excessively high and the hardness increases, and it becomes impossible to follow the deformation during pre-scaling, resulting in cracks. It is not desirable because it lowers the sex. The ratio of the amount of the cross-linking agent to the ethylene-non-carboxylic acid copolymer may vary depending on the amount of carboxyl groups in the copolymer. With respect to 100 parts by mass, the crane U is 0.5 to 50 parts by mass (more preferably 5 to 20 parts by mass).

The cross-linking agent having two or more functional groups capable of reacting with a lipoxyl group in one molecule is not particularly limited, but may be sorbitol polyglycidyl ether, (poly) glycerol-one-polypropylidicyl ether, or pen-erythritol polydali. Contains glycidyl group such as polyglycidyl ethers such as sidyl ether, trimethylol-propane polyglycidyl ether, neopentyl diol alcohol diglycidyl ether, (poly) ethylene glycol diglycidyl ether, and polyglycidylamines such as polyglycidylamine Frame il; 4,4, -bis (ethyleneiminecapo: ^ reamino) diphenylmethane, Ν, Ν, 1-hexamethylene-1,6-bis (1-aziridinecarboxamide), Ν, Ν, diphenylmethane-1 4 , 4 'one bis (one aziridine carboxamide), toluene bis Bifunctional aziridine compounds such as dilysine carboxamide; tri-11-aziridinylphosphinoxide, tris [1_ (2-methyl) aziridinyl] phosphinoxide, trimethylo-propanetris (] 3-aziridini Tripropionate), tris-2,4,6-((1-aziridinyl) -11,3,5-triazine, tetramethylpropanetetraaziridinylpropionate, etc. Preferred examples include crosslinking agents having an aziridinyl group, such as the present invention, and one or more of these can be used. Among them, an aziridinyl group-containing crosslinking agent is preferable. , Monofunctional aziridine (such as ethyleneimine) may be used in combination. 5 to 40% by mass (more preferably 20 to 30% by mass) of silica particles may be contained. It is effective not only for improving but also for improving the corrosion resistance after degreasing and the tape peeling resistance. If the amount of silica particles is small, it is difficult to achieve these effects, but if the amount is too large, the ratio of the silica particles becomes too high to deteriorate the film-forming property, and cracks may occur in the resin male during the drying process. However, it is not preferable because it leads to a decrease in corrosion resistance. In addition, the silica particles act as an additive II, increasing the lubricity of the coating and reducing the coefficient of friction, causing wear of the mold during calorie and possibly shortening the life of the mold.

 In order to maximize the effect of the sily particles, the average particle diameter of the sily particles is preferably in the range of 1 to 200 nm. If the particle size of the silica particles exceeds 200 nm, the surface of the shelf may be roughened to form a dense resin male, and the silica particles may also act as an enhancement. Workability deteriorates. The smaller the particle size of the silica particles, the better the corrosion resistance of the coating. However, if the particle size is extremely small, the above-mentioned effect is likely to occur. Therefore, the lower limit of the particle size is preferably 1 nm. In particular, when importance is attached to the corrosion resistance after degreasing, the average particle diameter of the silica particles is preferably in the range of 4 to 2 O nm. Such silica particles are commonly known as colloidal silica, and include, for example, “XS”, “SSJ”, “40”, and “N” in the “Snowtex” series (colloidal silica of Nissan Kagaku ring). , "UP" and the like can be suitably used.

 It is preferable that the emulsion of the present invention contains a wax. If the wax is contained in the range of 0.5 to 20% by mass (more preferably 0.5 to 0.5% by mass, more preferably 0.5 to 5% by mass) in terms of solid content, The resulting resin film has good lubricity, scratch resistance, deep drawability required for pressing and punching, punching, mold abrasion resistance, and blackening resistance of the sliding surface during karoe. Become. However, if the amount of wax is too large, the wax softens or liquefies or reforms and concentrates at the interface between the resin film and the resin layer or between the surface modified layer and the fine resin layer. It is not preferable because the corrosion resistance and the tape peeling resistance are deteriorated.

The wax is not particularly limited, and natural waxes such as microcrystalline phosphorus wax and paraffin wax; synthetic waxes such as polyethylene; and waxes such as a mixture thereof can be used. The softening point is 80-140. Choose C stuff Is preferred. The most common wax is spherical polyethylene wax, which has an average particle diameter of 0 :! To 3 m (more preferably 0.3 to 1.0 m) are preferred. This is because lubrication, punching, mold wear resistance, and drawability can be significantly improved. Examples of the spherical polyethylene wax include “DIJET Ε-17” (manufactured by Kyowa Kagaku), “KUE-1”, “KUE-5”, “KUE-8” (manufactured by Sanyo Chemical Industries), "Chemipearl" series ("W-100", "W-200", "W-300", "W-400", "W_500", "W- Commercially available products such as "640", "-700" and "ELEVON E_20" (Nikka Kasei) can be suitably used.

 The emulsion used in the present invention may be composed of essential components such as an ethylene-unsaturated carboxylic acid copolymer, the above-mentioned amines, a monovalent metal compound, and an aziridine compound. It is preferable that the particles include particles of a sili-can force, a plex or the like. The ethylene monounsaturated carboxylic acid copolymer is adjusted in the amount of the aziridine compound, the silica particles, and the particles such that the resin component accounts for 50% by mass or more of the solid content of the emulsion composition. It is good.

 The method for preparing emulsified pirates is as follows. First, an essential component, an ethylene-non-hydrocarbonic acid copolymer, is put into a homogenizer body, for example, along with a water-based pen, and if necessary, 70 to 250 °. Add the above amines and monovalent metal compounds in the form of a difficult 7K solution, etc. while heating at C (add the above amines first or add the above amines and monovalent metal compounds And added almost simultaneously), wins with high shear. Silica particles, wax, and IJ may be added at any stage, but it is desirable that after the addition of Izuru IJ, heat should not be applied so that the crosslinking reaction does not proceed and gelation occurs.

Emulsion as described above includes a diluting solvent, an anti-skinning agent, a leveling agent, a defoaming agent, a u-emulsifier, a sizing aid, a coloring pigment, a thickening agent, as long as the object of the present invention is not impaired. A silane coupling agent, another resin, or the like may be appropriately added. In addition, various additives that can be blended in the emulsion composition described above include other additives for forming a top coat shelf film. It can also be used when using objects. To form a resin male on a metal plate, the emulsion composition is applied to the metal plate by a known coating method, that is, a roll coating method, a spray method, a curtain flow coating method, or the like. What is necessary is just to apply | coat to one side or both sides of the surface, and to heat and dry. The heating wheel J is preferably performed at J where the crosslinking reaction between the crosslinking agent used and the lipoxyl group proceeds. When spherical polyethylene wax is used as the lubricant, the spherical shape is maintained at 70 to 130 because maintaining the spherical shape improves the workability in the subsequent processing steps. It is better to do で ^ in the range of (:).

The coating amount (thickness) of the resin film after drying is preferably 0.2 to ^2.5 gZm ² . If it is too thin, it will be difficult to obtain the desired balance of film properties such as workability, corrosion resistance, and paintability. However, when the amount of adhesion exceeds 2.5 gZm ² , the grounding property, that is, the conductivity when used in a computer housing or the like is unpreferably reduced. Furthermore, when the amount of the resin film peeled off during press working increases, the peeling ^ E adheres and accumulates on the mold, causing troubles in press forming and wasteful SSit cost. A more preferred lower limit of the resin film adhesion amount is 0.5 g / m ² , and an upper limit is 2.0 g / m ² .

By forming the above resin film on the surface modified layer, the surface-treated steel sheet according to the first aspect of the present invention can be obtained. Depending on the application, this surface treatment »-based steel sheet can be used as it is after processing, or it can be used as is, or electrodeposition coating, powder coating, silk printing under conventional conditions (130-: 160 ° C, 20 ° C) ~ 30 minutes). The surface-treated zinc-based steel sheet of the present invention does not contain any harmful hexavalent chromium, and has excellent tape peeling resistance that the present inventors have recognized as a problem for the first time and tape peeling resistance after alkali degreasing. I have. In addition, when a film obtained from a specific emulgeon pirates is selected as the overcoating male, it is excellent in various properties such as paintability, lubricity, calorie, corrosion resistance, etc. After! ^ A surface-treated zinc-based steel sheet having a skin with excellent peelability was formed. Therefore, it can be widely and effectively used, for example, as a surface-treated zinc-based steel sheet for automobiles, home appliances, building materials, and the like. Hereinafter, the present invention will be described more specifically with reference to Examples. However, the present invention is not limited to the following Examples in addition to the present invention. It is also possible to implement them, and all of them are included in the technical scope of the present invention. In the following examples, “%” and “parts” mean “% by mass” and “parts by mass” unless otherwise specified.

 Experimental Example 1 (No. 1-29)

A zinc plated steel sheet (product number: SECC) with a zinc plating of 20 g Zm ² applied to the surface of a 0.8 mm thick steel sheet by electroplating, washed with water and fiber Was used as an original plate. The surface treatment agent is a mixture of an aqueous solution of aluminum biphosphate (Nihon Kagaku Ring, solid content 50%), colloidal silica ("Snowtex 100"; Nissan Kagaku Kogane Ring) and water It was used. As shown in Tables 1 and 2, by changing the amount of aluminum biphosphate aqueous solution, colloidal silica and water, or adding phosphoric acid or metallic aluminum as needed, The contents of Si, P, and A1 in the surface modified layer were changed by changing the pith of P and A1.

 The degreased galvanized steel sheet was immersed in the surface treatment agent for 2 seconds, then pulled up, excess solution was removed with lingual roll, and then washed with a spray pressure of 50 kPa for 5 seconds, and washed with water for 40 seconds. A surface modified layer was formed on the zinc plating layer by fibering at ° C. No. 29 in Table 2 was not washed with water.

Separately, a polyolefin dispersion ("Chemipearl S100"; Chemipearl is a registered trademark; Mitsui Kasei) and an epoxy-type crane (1 ("Rica Pond AP3555B"; Chuo Rika Kogane) Solid content of 5% '(value when solid content of 100% of solid material for forming a top-coat reversal male is the same: the same applies hereinafter), silica particles having a particle size of 10 to 2 O nm (Snowextex 4 0 "; Nissan Chemical Industry Co., Ltd.) and a spherical polyethylene wax (" Chempearl W700 "; Mitsui Chemicals, Inc.) so as to have a solid content of 5%. The above composition was applied with a single coat on the surface-modified layer of a zinc-coated steel sheet, and dried by heating at 90 ° C for 1 minute. A surface-treated galvanized steel sheet having a coating amount of IgZm ² formed thereon was obtained. For each of the test materials obtained, the following methods were used to determine the knee (%) of Si, P, and A1 in the surface treatment solution, and the amounts of Si, P, and A1 in the surface modified layer (mg / m ² ) An advisory test was conducted on the total amount of the surface modified layer (mg / m ² ), the tape peeling resistance and the tape peeling resistance after alkali degreasing, and the results are shown in Table 1.

 瞧 Method]

 (1) Amount of S i, P and A 1

The difficulty of Si, P and A1 in the surface treatment solution was determined by the ICP emission spectrometer (manufactured by Seiko Co., Ltd.) using the amounts of Si, P and A1 in the surface modified layer (mg / m ² ). Was measured by fluorescence Χΐδβ (trade name “MIF-2100”; manufactured by Shimadzu Corporation). The total adhesion amount of the surface modification layer (mg / m ²⁾ is, S i by X-ray fluorescence analysis, based on the quantitation result of the P and A 1, these S I_〇 _{2, A1 P0 4,, Zn} 3 (P0 ₄₎ is _2, a 1 ₂ 〇 ₃ and the value calculated by the i ¾ are generated modified layer becomes.

 (2) Tape peeling resistance

 Attach a filament tape (# 9510; manufactured by Sliontec) to the surface of the test material and store it in an atmosphere of 40 ° C and 98% RH for 24 hours and 48 hours, then peel off the filament tape and the overcoat film remains. The area ratio was calculated, and thanks were given based on the following criteria. ◎: 100% survival rate

 〇 to ◎: Residual rate 95% or more and less than 100%

 〇: Survival rate 90% or more and less than 95%

 Δ: Residual rate: 70% or more and less than 90%

 X: Residual rate less than 70%

 (3) Tape peeling resistance after degreasing

The test material is immersed in a degreasing solution adjusted to 60g at 20g / 1 at an alkaline degreasing agent ("CL-N364S": Nippon Park Rising Nine ± ¾) for 2 minutes, pulled up, washed, and dried. After that, a cellophane tape (Nichiban Co., Ltd.) was applied to the surface of the test material and peeled after 24 hours and 48 hours. The area ratio of the remaining topcoat film was measured. The same as gender »consulted. Concentration in surface treatment agent Surface modification ratio in surface modification layer Ratio

 (%) Sato (mg / m)

Si P Al Si / P Si / Al Si P Al Si / P P / Al (mg / m) Λ ^,

 0.65 0.1 0.03 6.5 21.7 Yes 6.5 1.2 1.0 5.4 1.2 18.8

0.3 0.05 0.02 6.0 15.0 Y7

 Shellfish Yes 4.1 1.0 0.8 4.1 1.3 12.9

0.08 0.02 0.007 4.0 11.4 With immersion 3.3 0.8 0.7 .4'1 1.1 10.2

0.02 0.005 0.002 4.0 10.0 Yes 1.9 0.9 0.6 2.1 1.5 8.1

0.005 0.0007 0.0003 7.1 16.7 Immersion Yes 1.1 0.5 0.5 2.2 1.0 4.5

1.0 0.16 0.06 6.3 16.7 Soaked Yes 8.2 1.5 1.2 5.5 1.3 23.8

2.0 0.3 0.1 6.7 20.0 Immersion Yes 11.8 2.0 1.9 5.9 1.1 33.5

4.2 0.7 0.25 6.0 16.8 With shellfish 14.4 2.8 1.4 5.1 2.0 44.6

3.8 1.3 0.4)

 2.9 9.5 Yes 15.0 2.9 1.4 5.2 2.1 46.5

0.08 0.04 0.012 2.0 6.7

 ■ / Kankai Yes 4.0 0.7 0.6 5.7 1.2 11.4

0.08 0.05 0.015 1.6 5.3 ,, /, 7

 ■ fe shell available 4.1 0.9 0.7 4.6 1.3 12.6 -½-

0.08 0.03 0.009 2.7 8.9 Shellfish Yes 3.7 0.7 0.8 5.3 0.9 11.0

1.0 0.1 0.03 10 33) Yes 10.1 1.8 1.6 5.6 1.1 28.8

2.0 0.1 0.03 20 67 y Yes 11.3 1.7 1.6 6.6 1.1 31.1

4.0 0.13 0.038 31 105 Soaked Yes 12.0 1.9 1.8 6.3 1.1 33.5

4.4 0.1 0.03 44 147 Dipping Yes 13.0 1.8 1.8 7.2 1.0 35.4

4.2 0.07 0.02 60 210 Immersion Yes 12.6 1.1 1.3 11.5 0.8 32.0

4.5 1.3 0.5 3.5 9.0 Immersion Yes 25.1 13.6 9.2 1.8 1.5 114.3

Peeling off the surface-modified tape in the surface-modified layer Concentration (%) in the surface treatment agent after degreasing Ratio Ratio

 No. Treatment method Immediately after washing ng / m) Eyebrow separation

Releasability category lr A1 ol / roi / / A Λi lr ol / rr / Al (mg / m ² ) 4n 4οη 4on

 19 4.3 1.0 0.8 4.3 5.4 Immersion Yes 22.3 3.2 6.4 7.0 0.5 67.2 ◎ 〜〇 Δ △ Δ Reference example

20 0.001 0.0006 0.0002 1.7 5.0 Immersion Available 0.8 0.5 0.5 1.6 1.0 3.8 X X Δ Δ Comparative example

21 0.004 0.0002 0.00006 6.7 20.0 Immersion Yes 0.5 0.4 0.3 1.3 1.3 2.8 X X △ X Comparative example

22 0.001 0.1 0.03 0.01 0.03 Immersion Yes 0.8 1.8 1.6 0.4 1.1 8.9 ΔX 〇 Δ Comparative example

23 0.1 0.0002 0.00006 1667 500 Immersion Available 0.8 0.4 0.2 2.0 2.0 3.7 X X Δ X Comparative example

24 8.2 2.0 0.7 4.1 11.7 Immersion Yes 38.2 15.3 10.2 2.5 1.5 150.3 〇 Δ X X Comparative example

25 8.4 3.0 0.4 2.8 21.0 Immersion Yes 40.1 17.7 10.0 2.3 1.8 169.9 〇 Δ X X Comparative example

26 4.4 5.1 0.5 0.9 8.8 Immersion Yes 27.3 16.2 9.5 1.7 1.7 134.4 ◎ 〜〇 Δ △ X Comparative example

27 3.7 1.3 0.7 2.8 5.3 Immersion Yes 14.6 13.1 11.5 1.1 1.1 83.0 ◎ 〜〇 Δ Δ Δ Comparative example

28 8.0 1.5 0.5 5.3 16.0 Yes 33.5 9.1 8.6 3.7 1.1 108.9 ΔX Δ Δ Comparative example

29 0.6 0.3 0.15 2.0 4.0 None 45.1 20.1 15.5 2.2 1.3 181.0 〇 〇 XX Comparative example

Table 1 shows examples of the present invention. In all of these, the Si, P, and A1 contents and the SiZP and PZA1 in the surface-modified layer are all within the appropriate ranges, and excellent tape peeling resistance in both the dry state and after degreasing have. In N 0.19 of Table 2, P / A 1 was smaller than the appropriate range, so that the tape peeling resistance and the tape peeling resistance after degreasing were slightly inferior to those of the examples of the present invention.

 No. 20 to 23: One or more of the Si, P, and A1 adhesion amounts in the surface modified layer due to lack of some or all of the concentration of Si, P, and A1 in the surface modifier. All or some of them do not reach the specified amount, and both the tape peeling resistance and the tape peeling resistance after alkali degreasing are inferior to those of the present invention.

 No. 24 to 28: The Si, P, and A1 concentrations in the surface modifier are too high or a part of the Si, P, and A1 concentrations in the surface modifier. Some or more than the specified amount, and both the tape peeling resistance and the tape peeling resistance after alkali degreasing are inferior to those of the present invention.

 No. 29: The amount of P and A1 adhered to the surface modified layer exceeded the specified amount because water washing was not performed, and the tape peeling resistance was good, but »J amount of P and A1 As a result, the resistance of the surface-modified layer to resistance is reduced, and the resistance to tape peeling after degreasing is reduced.

 Experimental Example 2 (No. 30 to 48)

The surface modified layer was prepared by using the spray method instead of the immersion method. In other words, a surface treatment agent having the composition shown in Table 3 (preparation method was the same as that in Experiment Example 1) was sprayed onto the degreased steel sheet in Experiment Example 1 at a spray pressure of 50 kPa for 2 seconds. The excess solution was rinsed with Ringerol! ^, And further washed with water at a spray pressure of 50 kPa for 5 seconds and dried at 40 ° C to form a surface modified layer on the zinc plating layer. . Otherwise, in the same manner as in Experimental Example 1, a surface-treated steel sheet with a top coat formed thereon was obtained. Each of the obtained test materials was crossed in the same manner as in Experimental Example 1, and the results are shown in Table 3. Concentration in surface treatment agent. Clothing-resistant tape in surface modification layer Ratio Ratio

 (%) Total number of layers

Treatment washing straight, mg / m ²⁾ of Ousato

 Si P Al Si / P Si / Al Si P Al Si / P P / Al (mg / m) 24h 4

4.4 1.5 0.5 2.9 8.8 With spray 29.0 14.7 9.9 2.0 1.5 127.6 ◎ 〜〇

4.1 1.4 0.4 2.9 10 With spray 22.3 13.2 9.0 1.7 1.5 106.3 ◎ 〜〇

3.5 1.3 0.4 2.7 8.8 With spray 17.3 12.0 8.0 1.4 1.5 90.8 ◎ 〜〇

2.3 0.9 0.3 2.8 8.3 With spray 12.0 9.2 7.5 1.3 1.2 63.3 ◎

1.5 0.9 0.2 1.7 7.5 With spray 9.0 8.5 6.7 1.1 1.3 54: 6 ◎

1.5 0.6 0.2 2.5 7.5 With spray 8.8 6.8 5.2 1.3 1.3 47.5 ◎ ◎

1.4 0.2 0.07 7.0 20 With spray 8.7 4.3 3.8 2.0 1.1 35.7 ◎ ◎

1.0 0.1 0.03 10 33 With spray 6.7 3.8 3.1 1.8 1.2 29.9 ◎ ◎

0.5 0.06 0.02 8.3 25 Spray 5.3 2.7 2.4 2.0 1.1 22.1 ◎ ◎

0.4 0.04 0.01 10 40 With spray 5.2 4.0 1.0 1.3 4.0 33.4 ◎ ◎

0.5 0.08 0.02 6.3 25 Spray 5.5 3.0 1.4 1.8 2.1 26.8 ◎ ◎

0.5 0.02 0.008 25 63 with spray 4.1 2.0 1.2 2.1 1.7 18.1 ◎ ◎

0.07 0.005 0.003 14 23 With spray 3.8 1.1 0.7 3.5 1.6 13.2 ◎ ◎

0.008 0.0008 0.0003 10 27 Spray 2.0 0.9 0.6 2.2 1.5 8.3 ◎

0.001 0.0004 0.00007 2.5 14 Spray 0.8 0.4 0.3 2.0 1.3 3.4 X

0.007 0.0004 0.0002 18 35 Spray 1.1 0.4 0.6 2.8 0.7 4.4 Δ

4.5 1.7 0.6 2.6 7.5 With spray 19.2 16.1 2.5 1.2 6.4 134.9 Δ

2.2 1.8 0.7 1.2 3.1 With spray 14.3 18.2 12.1 0.8 1.5 112.2 ◎ ◎

7.0 1.0 0.4 7.0 18 With spray 37.2 10.0 8.1 3.7 1.2 120.7 △

Experimental example 3 (No. 49-72)

 As a surface treatment agent, a mixed solution of the above-mentioned aluminum biphosphate aqueous solution, colloidal silica (the above-mentioned “Snotex ™”), three types of polyacrylic acid and water was used, and the results are shown in Table 4 (the same applies to Table 5). The surface treatment agent was prepared. First, the spray method (under the same conditions as in Experimental Example 2) was used to obtain a surface-treated zinc plated steel sheet before the formation of the overcoating sword. Nos. 49 to 60 were obtained by forming a top coat in the same manner as in Experimental Example 1.

On the other hand, separately, the autoclave was charged with 626 parts of water and ethylene-acrylic acid copolymer (acrylic acid 20% by mass, melilet index (Ml) 300) 160 咅] 5, and the above ethylene-acrylic acid 150 mol% of triethylamine and 15 mol% of Na〇H are added to 1 mol of the hydroxyl group in the copolymer, and 150. (: In a 5Pa atmosphere, a high-speed victory was obtained to obtain an ethylene-acrylic acid copolymer emulsion. Subsequently, a glycidyl group-containing crosslinking agent ("Epiclone CR5 LJ (CR5L and "Epiclone" is a registered trademark; Dai Nippon Ink Chemical Co., Ltd. ± S) is a solid content of 5% by mass (solid content of emulsion yarn (non-volatile content) is 100% by mass; the same applies hereinafter). ) And an aziridinyl group-containing cross-linking agent (4,4'-bis (ethyleneiminocarbonylamino) diphenylenemethane; "chemitite DZ-22E" (DZ-22 pounds and 0 each); Trademark: Nippon Shokubai (t ^) is 5% by mass in solid content, Siri force particles with particle diameter of 10 to 20 nm ("Snowtex 40", made by Nissan Chemical Industries Co., Ltd.) are 30% in solid content, and softening point is 120. ° C, spherical polyethylene with an average particle size of 1 / xm The emulsion composition was prepared in such a manner that the composition became 5%, and an emulsion composition was prepared The above emulsion composition was placed on the surface-modified layer of the surface-treated zinc plated steel sheet before the above-mentioned top coat skin Fujinari. It was coated with a bar coat, heated and dried at a plate temperature of 90 ° C. for 1 minute to form an overcoat of lg / m ² to form a resin overcoat (No. 61 to 72).

Each of the obtained test materials was subjected to the same procedure as in Experimental Example 1, and the results are shown in Tables 4 and 5. In the table, PA1 is weight average ^ "amount (Mw) of polyacrylic acid of 100,000 to 200,000), PA2 is polyacrylic acid of Mw 20,000 to 30,000, and PA3 is Mw80. 00 polyacrylic acid. The absorption intensity of the resin in the surface-modified layer is a value measured by FT-IR, and the analysis conditions are as follows.

 [FT—IR analysis method]

 Measuring method: High-sensitivity reflection method (incident angle 75 °, irradiated with infrared light with parallel polarization) Comparative material: gold-deposited mirror

Competence: 4 cm- ¹

 Number of accumulation: 500 times

 Equipment: JIR-5500 Fourier transform infrared spectrometer manufactured by JEOL Ltd.

 IR-RSC110 reflection measurement unit (variable angle type)

 I R-SEM100 sample switching stage

Polyacrylic acid from 1496 cm ^ peak one click area l 776 cm- ¹ of添Ka卩steel sheet, minus the peak area of 1496 cm ^ l 776 cm- ¹ of the steel sheet which is not a polyacrylic acid添Ka卩This was taken as the absorption derived from polyacrylic acid in the surface-modified layer.

FT-IR spectra of No. 38 shown in Table 3 above, No. 52 shown in Table 4, and sodium polyacrylate (standard sample) measured under the above conditions are shown in FIGS. Was. No. 52 in Fig. 2 is the system in which PA1 was included in the 0.50 gZ1 surface treatment agent, and was recognized in the No. 38 vector where polyacrylic acid was not included in the surface treatment agent. Absorption of 1346 cm- ¹ and 142 lcm- ¹ and 1457 cm-1592 cm- ¹ was observed. These peaks are consistent with the absorption of sodium polyacrylate shown in FIG.

Table 4

It can be seen that the organic tree-added system has better tape peeling resistance and tape peeling resistance after alkali degreasing than conventional non-added systems. In the case where a top coat consisting of the emulsion thread neutralized by a specific neutralization method was formed (shown in Table 5), the excellent tape peeling resistance and tape peeling resistance after alkali degreasing were observed. It can be seen that it shows. Industrial applicability

 A surface-modified layer was formed on the zinc-based plating layer of the zinc-based plating steel sheet with a specific amount of Si, P, and A1 and, if necessary, a surface treatment agent containing an organic resin. The peelability and the tape peeling resistance after alkali degreasing were excellent. In addition, by selecting a male obtained from a specific emulsion fiber as the top-coating male, it is excellent in various properties such as paintability, lubricity, calorie and corrosion resistance, and also has excellent tape peeling resistance after degreasing process. It was possible to provide a surface-treated zinc-based steel sheet on which a film having excellent performance was formed. The i¾t method of the present invention is a suitable method for producing a surface-treated zinc-based steel sheet having excellent tape peeling resistance, particularly excellent tape peeling resistance after alkali degreasing.

Claims

The scope of the claims 1. A surface-treated zinc-based steel sheet in which at least a surface-modified layer and an overcoat are formed on a zinc-based plated layer of the zinc-based plated steel sheet, wherein the surface-modified layer has a Si conversion value. in the S i 0 ₂ of 1~3 Omg / m ^2, the resistance to tape peeling resistance, characterized in that it comprises a a 1 P and 0. 4~1 Omg / m ² of 0.. 5 to 15 mg / m ² Excellent surface treatment Zinc-based steel sheet. 2. The surface treatment according to claim 1, wherein the content (mass ratio) of Si, P, and A1 contained in the surface modified layer satisfies the relationship of the following formulas (1) and (2). Zinc plating steel sheet.  0.5 ≤ S iZP ≤ 20 ... (1)  0.7 ≤F / A 1≤6 …… (2) 3. The surface-treated zinc-coated steel sheet according to claim 1, wherein the surface-modified layer further contains an organic resin. 4. The organic resin is included so that the absorption bow ti derived from the structure of the organic resin is 0.1 to 15 when the surface modified layer is observed by FT-IR. The surface-treated plated steel sheet described in 3. 5. The surface modification layer surface treated zinc-based plated steel sheet of the serial placement in claim 1 attached amount in the range of 4. 2~13 Omg / m ² of. 6. The overcoated ceria is a resin male obtained from an emulsion of ethylene-dicarboxylic acid copolymer as a main component. -In addition to the unsaturated carboxylic acid copolymer, an ethylene-unsaturated carboxylic acid copolymer having a boiling point of 100 ° C or less, equivalent to 0.2 to 0.8 moles per mole of lipoxyl group. Amine and a monovalent metal compound equivalent to 0.02 to 0.4 mole per mole of the lipoxyl group of the ethylene-non-carboxylic acid copolymer, and react with the carboxyl group. 2. The surface-treated zinc-based plated steel sheet according to claim 1, wherein the crosslinked agent having two or more functional groups to be obtained is contained in an amount of 1 to 20% by mass based on 100% by mass of the solid content of the emulsion composition. 7. A S i0 ₂ containing phosphate-based surface treatment agent for forming the surface modification layer on the zinc-based plated steel sheet, solid content means a 0.5 01-14. 5% (wt% The same shall apply hereinafter), and it is assumed that the amount of Si, P, and A1 contained in the treatment agent and the yarn ratio (mass ratio) satisfy the following requirements. .  S i: 0.002 to 4.5%  P: 0.0005 to 1.5%  A1: 0.0001 to 0.5%  1. 5≤S i / P≤60, 4. 5≤S i / Al≤230 8. The surface treatment agent according to claim 7, wherein the surface treatment agent further contains an organic resin. 9. The surface treatment ij according to claim 8, wherein the organic resin is 7-soluble. 10. The surface treatment agent according to claim 8, wherein the organic resin is contained in the surface treatment agent in a solid content of 0.01 to 3 g / l. 11. A method for producing a surface-treated zinc-coated steel sheet according to claim 1, comprising: forming a surface-treating agent layer on the surface of the zinc-based plated steel sheet with the surface-treating agent according to claim 7; Then, surplus P and / or A1 is removed from the surface treatment agent layer, and then the surface modified layer is formed by removing the excess P and / or A1. 12. The i¾i method according to claim 11, wherein the surface treatment agent layer is formed by spray removal.