JP3142732B2 - Organic composite coated steel sheet with excellent electrodeposition coating properties, paint adhesion, bare corrosion resistance after processing and weldability - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic composite coated steel sheet having excellent electrodeposition coating properties, paint adhesion, bare corrosion resistance after processing and weldability.

[0002]

2. Description of the Related Art In recent years, there has been an urgent shift from organic solvent-based paints to water-based paints due to flammable explosions of organic solvents in paints, air pollution, occupational safety and hygiene problems.

In the industries of automobiles, steel furniture, household appliances and the like, the use of pre-coated metal materials is increasing in order to improve productivity.

[0004] In the field of surface treatment paints, various pre-coated steel sheets have been developed in order to respond to such demands. In this field, however, the conversion from conventional organic solvent-based paints to water-based paints is urgently required. .

[0005] Even in a system using a conventional organic solvent-based paint, in order to ensure conductivity, which is an essential condition for ensuring electrodeposition coating property, Japanese Patent Publication No. 45-2430 and Japanese Patent Publication No. 4-6882 are disclosed. Although publications and the like propose zinc-rich paints, electrodeposition coating is possible with zinc-rich paints, but the smoothness of the painted surface is insufficient.

Further, Japanese Patent Publication No. Sho 52-44569, Japanese Patent Publication No. Sho 58-19706, and Japanese Patent Laid-Open Publication No. Sho 51-79138.
In JP-A-58-138758 and the like, paints containing a conductive pigment for enabling electrodeposition coating are provided and are commercially available.

However, in this paint, particles having a relatively large particle size (average particle diameter of 1 μm or more) such as metal powder such as zinc, metal carbide powder and metal phosphide powder are used as conductive pigments. Therefore, the formed coating film has irregularities, or a scratch due to a conductive substance added during press working adheres to the steel sheet surface, and the unevenness or scratches remain on the electrodeposition coated surface, and then 2 coats, There was a problem that it remained on the coating film surface even after three coats were applied.

Further, Japanese Patent Application Laid-Open No. 58-224171,
JP-A-60-197778, JP-A-60-199
No. 074, JP-A-60-174879 and the like disclose an organic composite silicate film and its coated steel sheet. Although this organic silicate film does not contain a conductive pigment and is an extremely thin film having a thickness of 0.2 to 5.0 μm, it has high corrosion resistance due to a bond between an organic binder and colloidal silica, and a remarkable improvement in press workability and the like is observed.

[0009] However, in response to the problem of unevenness of the electrodeposition coating, in particular, the variation in the thickness of the organic composite silicate coating, the thickness of the electrodeposition coating formed thereon also varies greatly. That is, there is a problem that the electrodeposited coating film where the film thickness of the organic composite silicate coating film is large is thick, and the electrodeposition coating film where the film thickness is small is thin, and the unevenness is further enlarged by the electrodeposition coating film. .

[0010] Also, Japanese Patent Application Laid-Open No. Sho 62-283161,
In the method disclosed in JP-A-3-269067,
It requires the use of special organic solvents and special additives, and has the drawback of poor adhesion with adhesives such as PVC sols. It is not smooth and the smoothness is still insufficient. Further, since it is necessary to apply the coating film extremely thinly, it is necessary to dilute the coating material to be used sufficiently.

[0011]

SUMMARY OF THE INVENTION The object of the present invention is to provide excellent electrodeposition coating properties, that is, excellent smoothness of the coated surface after electrodeposition coating, excellent paint adhesion, and bare corrosion resistance and welding after processing. An object of the present invention is to provide an organic composite plated steel sheet having excellent properties.

[0012]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, completed the present invention.

That is, in the present invention, a Zn- and Zn-based alloy-plated steel sheet is subjected to a chromate treatment of 10 to 150 mg / m ^{2 in} terms of Cr, and a special organic resin is further added thereto in an amount of 0.3 to 3.0 g / m ^2.
An organic composite plated steel sheet characterized by being coated and dried.

The organic resin used in the present invention contains 15 to 35 parts by weight of a carboxyl group-containing α, β-unsaturated monomer and 25 to 40 parts by weight of a hydroxyl group-containing α, β-unsaturated monomer. , A monomer which is an essential component and is copolymerizable therewith.
30 to 6 parts of a vinyl oligomer composed of 5 to 60 parts by weight
0 parts by weight and an epoxy resin having a solid acid value of 25 to 50 obtained by reacting 40 to 70 parts by weight of the epoxy resin, further comprising unreacted carboxyl in the vinyl modified epoxy resin. More than 40% of the groups are neutralized with a basic compound and made aqueous.

The present invention will be described in more detail.

On a Zn-Ni-based alloy-plated steel sheet which has been subjected to electrolytic chromate treatment, 50 parts by weight of a vinyl-based oligomer and 50 parts by weight of an epoxy resin are shown so that the chromium deposition amount is 80 mg / m ^2. In a vinyl-modified epoxy resin having a solid content acid value of 40 in a part, 30 parts of a hydroxyl group-containing α, β-unsaturated monomer of a vinyl oligomer and 50 parts of a copolymerizable monomer are fixed, Group 8
0% basic compound, such as a carboxyl group-containing α neutralizing with ammonia, electrodeposition paintability when drying after coating so as to give a 1.3 g / m ² by changing the β- unsaturated monomer 1, 2, 3 and 4 show the relationship between the paint adhesion, the bare corrosion resistance after processing and the weldability. Here, the degree of neutralization of unreacted carboxyl groups was set to 80% by using ammonia.

Further, 50 parts of a vinyl-based oligomer and 50 parts of an epoxy resin were applied on a Zn—Ni-based alloy-plated steel sheet which had been subjected to electrolytic chromate treatment so that the chromium deposition amount was 80 mg / m ^2. Is a vinyl-modified epoxy resin having a hydroxyl group-containing α,
30 parts of β-unsaturated monomer and 50 parts of copolymerizable monomer
Part, and 25 parts of a carboxyl group-containing α, β-unsaturated monomer in which unreacted carboxyl groups are neutralized with ammonia at various ratios is fixed to 25 parts.
The relationship between the neutralization ratio of unreacted carboxyl groups and the electrodeposition coatability, adhesion to paint, bare corrosion resistance after processing and weldability when applied so as to obtain m ² is shown in FIGS. FIG.

Here, the electrodeposition coating property was evaluated by first baking at 175 ° C. using a commercially available electrodeposition paint, and then evaluating the appearance of the electrodeposition coating film. The evaluation indices are shown in Table 1.

Coating adhesion was measured by electrodeposition coating, melamine alkyd resin-based coating, 40 μm each, middle coating and top coating, immersion in warm water at 50 ° C. for 240 hours, followed by JI
In accordance with SK5400, drawing and cross-cut peeling test were performed. The evaluation indices are shown in Table 2.

[0020]

[Table 1]

[0021]

[Table 2]

The bare corrosion resistance after processing was evaluated by examining the corrosion resistance of the processed portion (side portion) by subjecting the test piece to cylindrical drawing, and the corrosion resistance test was performed by a salt spray test method according to JIS Z 2371 standard. , Salt solution concentration 5% by weight
At a temperature of 35 ° C. and a spray pressure of 20 PSI
Under the following conditions. After 4000 hours, the presence or absence of rusting and the degree of rusting were investigated and evaluated by the area where red rust was generated. The evaluation index is shown in Table 3.

The continuous weldability of each organic composite plated steel sheet is determined by using a CF-type electrode of Cu-Cr material under a condition of a pressure of 200 kgf and a conduction time of 0.2 seconds. The welding current was determined, continuous welding was performed with the welding current, the nugget diameter was measured at every 100 spots, and the number of spots until the nugget diameter became 5 mm was evaluated by an evaluation index as shown in Table 4.

[0024]

[Table 3]

[0025]

[Table 4]

As is apparent from FIG. 1, when the α, β-unsaturated monomer having a carboxyl group of the vinyl oligomer is changed, the electrodeposition coatability changes, and 15 to 35 parts shows excellent electrodeposition coatability. . If the amount is less than 15 parts or more than 35 parts, the electrodeposition coatability is reduced.

As is apparent from FIG. 2, when the carboxyl group-containing .alpha.,. Beta.-unsaturated monomer of the vinyl oligomer is changed, the paint adhesion changes and 15 to 35 parts show excellent paint adhesion. If the amount is less than 15 parts or more than 35 parts, the adhesiveness of the paint will be reduced.

As is apparent from FIG. 3, even if the carboxyl group-containing α, β-unsaturated monomer of the vinyl oligomer is changed, the bare corrosion resistance after processing does not change.

As is apparent from FIG. 4, the weldability does not change even if the carboxyl group-containing α, β-unsaturated monomer of the vinyl oligomer is changed.

As is clear from FIG. 5, when the unreacted carboxyl groups are neutralized with ammonia, the sharpness of the coating changes depending on the neutralization ratio, and when the ratio of the neutralized carboxyl groups becomes 40% or more. The appearance of the ED coating is significantly improved.

As is clear from FIG. 6, the ratio of the neutralized carboxyl group also affects the paint adhesion, and when the ratio becomes 40% or more, the paint adhesion is remarkably improved.

On the other hand, as is apparent from FIG. 7, even if the ratio of the neutralized carboxyl group changes, the bare corrosion resistance after processing is not affected.

The weldability is also the same, and is not affected even if the ratio of the neutralized carboxyl group changes as is apparent from FIG.

In a vinyl-modified epoxy resin having a vinyl oligomer content of 50 parts, an epoxy resin content of 50 parts and a solid content acid value of 40, the raw material for preparing the vinyl oligomer is as follows:
When the amount of the α, β-unsaturated monomer having a carboxyl group is fixed at 25 parts and the amount of the copolymerizable monomer is fixed at 50 parts, and the amount of the α, β-unsaturated monomer having a hydroxyl group is changed, Paintability,
Fig. 9 shows the relationship between paint adhesion, bare corrosion resistance after processing, and weldability.
This is shown in FIGS. 10, 11 and 12. Here, the degree of neutralization of unreacted carboxyl groups was set to 80% by using ammonia.

As is apparent from FIG. 9, when the hydroxyl group-containing α, β-unsaturated monomer of the vinyl oligomer is changed, the electrodeposition coatability changes, and 25 to 40 parts shows excellent electrodeposition coatability. If the amount is less than 25 parts or more than 40 parts, the electrodeposition coatability is reduced.

As is apparent from FIG. 10, the paint adhesion changes when the hydroxyl group-containing α, β-unsaturated monomer of the vinyl oligomer is changed, and excellent paint adhesion is exhibited at 25 to 40 parts. If it is less than 25 parts or more than 40 parts, the paint adhesion will be reduced.

As is clear from FIG. 11, even if the hydroxyl group-containing α, β-unsaturated monomer of the vinyl oligomer is changed, the bare corrosion resistance after processing does not change.

As is apparent from FIG. 12, the weldability does not change even if the hydroxyl group-containing α, β-unsaturated monomer of the vinyl oligomer is changed.

Next, in a vinyl-modified epoxy resin having a vinyl oligomer content of 50 parts and an epoxy resin content of 50 parts and an acid value of solid content of 40, the raw material for preparing the vinyl oligomer is a carboxyl group-containing α, β-unsaturated monomer. 25 parts of the body, 30 parts of a hydroxyl group-containing α, β-unsaturated monomer, and electrodeposition coating properties, paint adhesion, naked corrosion resistance after processing and FIG. 13 and FIG.
4, FIG. 15 and FIG. Here, the degree of neutralization of unreacted carboxyl groups is determined by using ammonia.
80%.

As is apparent from FIG. 13, the amount of the monomer copolymerized with the hydroxyl group-containing α, β-unsaturated monomer and the carboxyl group-containing α, β-unsaturated monomer of the vinyl oligomer is changed. The electrodeposition coating property changes, and excellent electrodeposition coating property is exhibited at 25 to 60 parts by weight, and when the content is less than 25 parts or more than 60 parts, the coating adhesion decreases.

As is apparent from FIG. 14, the amount of the monomer copolymerized with the hydroxyl group-containing α, β-unsaturated monomer and the carboxyl group-containing α, β-unsaturated monomer of the vinyl oligomer is changed. The electrodeposition coating property changes, and excellent paint adhesion is exhibited at 25 to 60 parts by weight, and when the amount is less than 25 parts or more than 60 parts, the paint adhesion decreases.

As apparent from FIG. 15, the amount of the monomer copolymerized with the hydroxyl group-containing α, β-unsaturated monomer and the carboxyl group-containing α, β-unsaturated monomer of the vinyl oligomer was changed. Even after processing, the bare corrosion resistance does not change.

As is apparent from FIG. 16, the amount of the monomer copolymerized with the hydroxyl group-containing α, β-unsaturated monomer and the carboxyl group-containing α, β-unsaturated monomer of the vinyl oligomer was changed. Even though the weldability does not change.

In the vinyl-modified epoxy resin,
50 parts of epoxy resin, solid content acid value is fixed at 40,
The raw material for preparing a vinyl oligomer is composed of 25 parts of a carboxyl group-containing α, β-unsaturated monomer, 30 parts of a hydroxyl group-containing α, β-unsaturated monomer, and 50 parts of a monomer copolymerized therewith. The relationship between the electrodeposition coatability, paint adhesion, bare corrosion resistance after processing, and weldability when the proportion of the obtained vinyl oligomer is changed is shown in FIGS. 17, 18, 19 and 20. Here, the degree of neutralization of unreacted carboxyl groups was set to 80% by using ammonia.

As is clear from FIG. 17, when the ratio of the vinyl oligomer in the vinyl-modified epoxy resin changes, the paint adhesion changes, and 30 to 60 parts shows excellent electrodeposition coatability. On the other hand, when the amount is less than 30 parts or more than 60 parts, the electrodeposition coating property decreases.

As is apparent from FIG. 18, when the ratio of the vinyl oligomer in the vinyl-modified epoxy resin changes, the paint adhesion changes, and 30 to 60 parts shows excellent paint adhesion. On the other hand, when the amount is less than 30 parts or more than 60 parts, the paint adhesion decreases.

As is clear from FIG. 19, when the proportion of the vinyl oligomer in the vinyl-modified epoxy resin changes, the bare corrosion resistance after processing changes, and 30 parts or more shows excellent bare corrosion resistance after processing.

As is apparent from FIG. 20, when the ratio of the vinyl-based oligomer in the vinyl-modified epoxy resin changes, the weldability changes, and 30 or more parts show excellent weldability.

Further, in the vinyl-modified epoxy resin,
The raw material for preparing a vinyl oligomer is composed of 25 parts of a carboxyl group-containing α, β-unsaturated monomer, 30 parts of a hydroxyl group-containing α, β-unsaturated monomer, and 50 parts of a monomer copolymerized therewith. The vinyl oligomer was fixed at 45 parts, the acid value of the solid content after the reaction was fixed at 40, and the ratio of the epoxy resin after the reaction was changed, the electrodeposition coating property, paint adhesion, and bare corrosion resistance after processing. 21, 22, 23, and 24 show the relationship between the weldability and the weldability. Here, the degree of neutralization of unreacted carboxyl groups was set to 80% by using ammonia.

As is clear from FIG. 21, when the proportion of the epoxy resin in the vinyl-modified epoxy resin is changed, the electrodeposition coatability changes. When the amount of the epoxy resin is 40 parts or more, the electrodeposition coatability is remarkably improved. On the other hand, if it is less than 40 parts, the electrodeposition coating property is reduced.

As is clear from FIG. 22, when the proportion of the epoxy resin in the vinyl-modified epoxy resin is changed, the adhesiveness of the paint changes, and when the amount of the epoxy resin is 40 parts or more, the adhesiveness of the paint is remarkably improved. On the other hand, if the amount is less than 40 parts, the adhesion of the coating material is reduced.

As is clear from FIG. 23, when the proportion of the epoxy resin in the vinyl-modified epoxy resin is changed, the bare corrosion resistance after processing changes, and the bare corrosion resistance is improved when the epoxy resin content is 70 parts or less. On the other hand, if it exceeds 70 parts, the bare corrosion resistance after processing decreases.

As is clear from FIG. 24, when the proportion of the epoxy resin in the vinyl-modified epoxy resin is changed, the weldability changes, and the weldability is improved when the epoxy resin content is 70 parts or less. On the other hand, if it exceeds 70 parts, the weldability is reduced.

Next, in the vinyl-modified epoxy resin, the starting materials for preparing the vinyl oligomer were 25 parts of a carboxyl group-containing α, β-unsaturated monomer and hydroxyl group-containing α, β
30 parts of unsaturated monomer and 5 parts of copolymerizable monomer
Electrodeposition coatability and paint adhesion when the vinyl oligomer was fixed at 45 parts, the epoxy resin was fixed at 55 parts, and the epoxy resin was fixed at 55 parts, and the acid value of the solid content in the resin after the reaction was changed. FIG. 25 and FIG. 2 show the relationship between the heat resistance, the bare corrosion resistance after processing and the weldability.
6, shown in FIGS. 27 and 28. Here, the degree of neutralization of unreacted carboxyl groups is determined by using ammonia.
80%.

As is apparent from FIG. 25, when the ratio of the acid value of the solid content of the vinyl-modified epoxy resin is changed, the electrodeposition coatability changes, and when the acid value of the solid content is 25 to 50, excellent electrodeposition coatability is exhibited. If it is less than 25 or more than 50, the electrodeposition coatability is reduced.

As apparent from FIG. 26, when the ratio of the solid content acid value of the vinyl-modified epoxy resin is changed, the paint adhesion changes, and when the solid content acid value is 25 to 50, excellent paint adhesion is exhibited. Alternatively, when it exceeds 50, the paint adhesion decreases.

As is apparent from FIG. 26, when the ratio of the solid content acid value of the vinyl-modified epoxy resin is changed, the paint adhesion changes, and when the solid content acid value is 25 to 50, excellent paint adhesion is exhibited. If it is less than 25 or more than 50, the paint adhesion will decrease.

As apparent from FIG. 27, when the ratio of the solid content acid value of the vinyl-modified epoxy resin is changed, the bare corrosion resistance after processing changes, and when the solid content acid value is 25 to 50, excellent bare corrosion resistance after processing is exhibited. If it is less than 25 or more than 50, the bare corrosion resistance after processing decreases.

As is apparent from FIG. 28, the weldability does not change even if the acid value of the solid content of the vinyl-modified epoxy resin is changed.

Incidentally, in the case of FIGS. 1 to 28 mentioned above, ammonia is exclusively used as the basic compound for neutralizing the unreacted carboxyl group. It goes without saying that any material such as sodium or the like may be used.

From the above results, as the vinyl-modified epoxy resin used in the present invention, carboxyl group-containing α, β-
15 to 35 parts by weight of an unsaturated monomer, and hydroxyl group-containing α, β
-25 to 40 parts by weight of an unsaturated monomer as an essential component, 30 to 60 parts by weight of a vinyl oligomer comprising 25 to 60 parts by weight of a monomer copolymerizable therewith, and an epoxy resin An acid value of the solid component obtained by reacting the resin with 40 to 70 parts by weight is 25 to 50, and the unreacted carboxyl group in the resin is changed to 4 by a basic compound.
A so-called aqueous resin in a neutralized form of 0% or more is used. This resin can be used as an aqueous or solvent-based resin.

Further, by using the above-mentioned vinyl-modified epoxy resin as a resin composition in which colloidal silica or aerosil is added, it is possible to further improve paint adhesion and naked corrosion resistance after processing.

On a Zn-Ni-based alloy-plated steel sheet subjected to electrolytic chromate treatment, 100 parts of vinyl-modified epoxy resin was applied so that the chromium deposition amount was 80 mg / m ² .
The figure shows the results of electrodeposition coating, paint adhesion, naked corrosion resistance after processing, and weldability when the aqueous liquid mixed with the added amount of colloidal silica changed to 1.3 g / m ² after drying. 29, FIG. 30, FIG. 31, and FIG.

The paint adhesion in FIG. 30 was determined by immersing the film in distilled water at 50 ° C. for 480 hours and then conducting a 2 mm gobang peeling test. The evaluation method is the same as in FIG. FIG.
The bare corrosion resistance after the processing of No. 1 was evaluated at the time point of 6000 hours after the salt spray test. The evaluation method is the same as in FIG.

As is apparent from FIG. 29, when the amount of colloidal silica added exceeds 60 parts, the electrodeposition coatability tends to decrease.

As is apparent from FIG. 30, when the amount of colloidal silica added was 10 to 60 parts, the adhesiveness of the paint was improved.
The amount slightly decreases when the amount is less than 10 parts, and decreases when the amount exceeds 60 parts.

As is apparent from FIG. 31, when the amount of colloidal silica added is 10 to 60 parts, the bare corrosion resistance after processing is greatly improved, and when the amount is less than 10 parts or more than 60 parts, it is lowered.

As is apparent from FIG. 32, when the amount of colloidal silica added exceeds 60 parts, the weldability decreases.

In addition, almost the same results were obtained when Aerosil was added instead of colloidal silica. From the above results, in the present invention, the amount of colloidal silica or aerosil added was 1 to 100 parts of the vinyl-modified epoxy resin.
0 to 60 parts.

The above vinyl-modified epoxy resin or the above resin composition can be used as a resin composition to which a curing agent has been added.

Examples of the curing agent include an amino resin, a blocked isocyanate compound, an epoxy compound, an aziridine compound, and a melamine compound. Although there is no particular limitation on these types, among these, amino resins and blocked isocyanate compounds having good storage stability with the resin are generally used. The addition amount is 1 to 50 parts based on 100 parts of the vinyl-modified epoxy resin. If it is less than 1 part, the function as a curing agent cannot be sufficiently exhibited, and if it exceeds 50 parts, adverse effects such as a decrease in water resistance may occur. Therefore, it is preferably 1 to 50 parts.

Next, Zn or Zn-Ni, Zn-Cr, Zn-chromate obtained by chromating the above resin or the above resin composition is used.
Cr-Ni, Zn-Mn, Zn-Fe, Zn-Cu, Z
It is applied and coated on a Zn-based alloy-plated steel sheet such as n-Al, Zn-Mg or the like, and the chromate used may be any of an electrolytic chromate, a coating chromate and a reactive chromate. The amount of adhesion is preferably 10 to 150 mg / m ^{2 in} terms of Cr. When the amount is less than 10 mg / m ² , corrosion resistance is not ensured and a resin or resin composition film having excellent adhesion cannot be obtained. On the other hand, if it exceeds 150 mg / m ^2, it is difficult to form a dense chromate film, and it is not possible to secure a resin or resin composition film having excellent adhesion.

The coating amount of the resin or the resin composition is preferably from 0.3 to 3.0 g / m ² .

[0074] This reduces the corrosion resistance in 0.3 g / m ^2, because the weldability in 3.0 g / m ² is reduced.

The above resin or resin composition can be applied by any method such as dip coating, shower coating, brush coating, spray coating and roll coating.

[0076]

The embodiments will be described below in detail.

Example 1 The adhesion amount was 20 g / m ² and the Ni concentration was 13.8%
The amount of Cr attached to the Zn-Ni alloy plated steel sheet
mg / m ^2, and 25 parts of the carboxyl group-containing α, β-unsaturated monomer and 35 parts of the hydroxyl group-containing α, β-unsaturated monomer were mixed with these. A solid-state acid value of 35 obtained by reacting 50 parts of a vinyl-based oligomer composed of 50 parts of a polymerizable monomer with 50 parts of an epoxy resin, and
An aqueous vinyl-modified epoxy resin, in which unreacted carboxyl groups in the resin were neutralized with trimethylamine by 80%, was applied so as to obtain 1.3 g / m ² after drying.

Example 2 The adhesion amount was 20 g / m ² and the Cr concentration was 11.5%
Of Zn-Cr based alloy plated steel sheet
mg / m ^2, and coated with 15 parts of a carboxyl group-containing α, β-unsaturated monomer and 25 parts of a hydroxyl group-containing α, β-unsaturated monomer. A solid-state acid value of 45 obtained by reacting 30 parts of a vinyl-based oligomer composed of 60 parts of a polymerizable monomer with 70 parts of an epoxy resin, and furthermore, in the resin, Unreacted carboxyl groups are converted to 1
A water-modified vinyl-modified epoxy resin in a neutralized form of 00% was applied so as to be 1.1 g / m ² after drying.

Example 3 The adhesion amount was 20 g / m ² and the Fe concentration was 11.0%
The amount of deposited Cr is 45
mg / m ^2, and 30 parts of a carboxyl group-containing α, β-unsaturated monomer, 35 parts of a hydroxyl group-containing α, β-unsaturated monomer, and 30 parts of the same. A solid-state acid value of 40 obtained by reacting 40 parts of a vinyl-based oligomer consisting of 50 parts of a polymerizable monomer with 60 parts of an epoxy resin. The reaction carboxyl group with ammonia
An aqueous resin composition obtained by adding 30 parts of colloidal silica to 100 parts of a water-modified vinyl-modified epoxy resin in a 100% neutralized form was applied so as to be 1.1 g / m ² after drying.

Example 4 A Zn-Al-based alloy-coated steel sheet having an adhesion amount of 30 g / m ² and an Al concentration of 5.0% had a Cr adhesion amount of 75 m
g / m ^2, and subjected to electrolytic chromate treatment, and 20 parts of a carboxyl group-containing α, β-unsaturated monomer, 30 parts of a hydroxyl group-containing α, β-unsaturated monomer, and 30 parts of the same. 5 of a vinyl oligomer composed of 40 parts of a polymerizable monomer
5 parts and 65 parts of the epoxy resin are reacted to obtain a solid acid value of 45, and
An aqueous resin composition obtained by adding 40 parts of Aerosil to 100 parts of an aqueous vinyl-modified epoxy resin in which unreacted carboxyl groups in the resin are neutralized with ammonia by 90% is dried. Thereafter, the composition was applied so as to have a density of 1.7 g / m ² .

Example 5 The adhesion amount was 20 g / m ² and the Ni concentration was 12.8%
The amount of Cr attached to the Zn-Ni-based alloy plated steel sheet
mg / m ^2, and 35 parts of a carboxyl group-containing α, β-unsaturated monomer, 30 parts of a hydroxyl group-containing α, β-unsaturated monomer, and 30 parts of the same. 30 parts of a vinyl-based oligomer composed of 45 parts of a polymerizable monomer and 60 parts of an epoxy resin are obtained by reacting the solid-state acid value of 50, and
A blocked isocyanate compound was added to 100 parts of an aqueous vinyl-modified epoxy resin in which 100% of the unreacted carboxyl group was neutralized with ammonia.
The dried aqueous resin composition was applied so as to be 1.5 g / m ² after drying.

Example 6 The adhesion amount was 20 g / m ² and the Ni concentration was 12.8%
The amount of Cr attached to the Zn-Ni alloy plated steel sheet
mg / m ^2, and 30 parts of a carboxyl group-containing α, β-unsaturated monomer, 35 parts of a hydroxyl group-containing α, β-unsaturated monomer, and 30 parts of the same. A resin obtained by reacting 40 parts of a vinyl-based oligomer consisting of 35 parts of a polymerizable monomer with 70 parts of an epoxy resin, and having a solid content acid value of 45, and the resin A solvent-based resin obtained by adding 40 parts of Aerosil and 10 parts of a blocked isocyanate compound to 100 parts of a solvent-based vinyl-modified epoxy resin in a form in which unreacted carboxyl groups therein are neutralized with triethylamine by 70%. The composition was applied so as to have a density of 1.3 g / m ² after drying.

Example 7 The adhesion amount was 20 g / m ² and the Cr concentration was 11.5%
The amount of deposited Cr is 55
mg / m ² of a coating type chromate treatment, and 20 parts of a carboxyl group-containing α, β-unsaturated monomer and 30 parts of a hydroxyl group-containing α, β-unsaturated monomer were mixed with these. A solid-state acid value of 40 obtained by reacting 40 parts of a vinyl oligomer composed of 30 parts of a polymerizable monomer with 60 parts of an epoxy resin, and
A solvent system in which 20 parts of Aerosil and 20 parts of a blocked isocyanate compound are added to 100 parts of a solvent-based vinyl-modified epoxy resin in which unreacted carboxyl groups in the resin are neutralized with triethylamine at 95%. The resin composition was applied so as to be 1.5 g / m ² after drying.

Example 8 The adhesion amount was 20 g / m ² and the Fe concentration was 11.0%
The amount of deposited Cr is 45
mg / m ^2, and 25 parts of the carboxyl group-containing α, β-unsaturated monomer and 35 parts of the hydroxyl group-containing α, β-unsaturated monomer were mixed with these. A solid content acid value of 25 obtained by reacting 40 parts of a vinyl oligomer composed of 30 parts of a polymerizable monomer with 60 parts of an epoxy resin, and
Unreacted carboxyl groups can be
An aqueous solution containing 50 parts of colloidal silica added to 100 parts of a water-modified vinyl-modified epoxy resin in a form of 100% neutralized was applied so as to have a density of 1.5 g / m ² after drying.

Example 9 A Zn-Al alloy plated steel sheet having an adhesion amount of 30 g / m ² and an Al concentration of 5.0% had a Cr adhesion amount of 75 m
g / m ^2, and 30 parts of a carboxyl group-containing α, β-unsaturated monomer, 25 parts of a hydroxyl group-containing α, β-unsaturated monomer, and 30 parts of the same. Vinyl oligomer 3 consisting of 40 parts of a polymerizable monomer
0 parts and 70 parts of the epoxy resin are reacted to obtain a solid content acid value of 35, and
Unreacted carboxyl groups can be
An aqueous solution containing 50 parts of colloidal silica added to 100 parts of a water-modified vinyl-modified epoxy resin in a form of 100% neutralized was applied so as to have a density of 1.5 g / m ² after drying.

Example 10 The adhesion amount was 20 g / m ² and the Ni concentration was 12.8%
The amount of Cr attached to the Zn-Al-based alloy plated steel sheet
mg / m ^2, and 35 parts of a carboxyl group-containing α, β-unsaturated monomer, 35 parts of a hydroxyl group-containing α, β-unsaturated monomer, and 35 parts of the same. A solid content acid value of 25 obtained by reacting 40 parts of a vinyl oligomer composed of 50 parts of a polymerizable monomer with 60 parts of an epoxy resin, and
100% unreacted carboxyl groups with triethylamine
An aqueous liquid obtained by adding 30 parts of Aerosil and 10 parts of a blocked isocyanate compound to 100 parts of the neutralized aqueous vinyl-modified epoxy resin was dried, and dried at 1.5 g /
It was applied as a m ^2.

Comparative Example 1 The adhesion amount was 20 g / m ² and the Ni concentration was 12.8%.
The amount of Cr attached to the Zn-Ni-based alloy plated steel sheet
mg / m ^2, and an aqueous polyester resin was applied after drying to 1.5 g / m ² .

Comparative Example 2 The adhesion amount was 20 g / m ² and the Ni concentration was 13.8%
Of Zn-Ni alloy plated steel sheet
The resultant was subjected to electrolytic chromate treatment so as to have a concentration of mg / m ^2, and a solvent-based acrylic resin was applied so as to be 1.3 g / m ² after drying.

Comparative Example 3 The adhesion amount was 20 g / m ² and the Ni concentration was 13.2%.
Of Zn-Ni-based alloy plated steel sheet
mg / m ^2, and 5 parts of a carboxyl group-containing α, β-unsaturated monomer and 45 parts of a hydroxyl group-containing α, β-unsaturated monomer were mixed with these. Vinyl oligomer 5 consisting of 50 parts of a polymerizable monomer
0 parts and an acid value of 15 obtained by reacting 55 parts of the epoxy resin, and unreacted carboxyl groups in the resin are 100% neutralized with triethylamine. The dried vinyl-modified epoxy resin in a sparse form was applied so as to have a weight of 1.5 g / m ² after drying. It is to be noted that the resin used in this example is not industrially usable because it is difficult to convert the resin itself into an aqueous solution.

Comparative Example 4 The adhesion amount was 20 g / m ² and the Ni concentration was 13.8%
The amount of Cr attached to the Zn-Ni alloy plated steel sheet
mg / m ^2, and coated with 10 parts of a carboxyl group-containing α, β-unsaturated monomer, 30 parts of a hydroxyl group-containing α, β-unsaturated monomer, and 30 parts of the same. A solid-state acid value of 20 obtained by reacting 40 parts of a vinyl-based oligomer consisting of 50 parts of a polymerizable monomer with 60 parts of an epoxy resin, and further comprising: An aqueous vinyl-modified epoxy resin in which unreacted carboxyl groups had been neutralized with triethylamine by 100% was applied so as to be 0.9 g / m ² after drying.

Comparative Example 5 The adhesion amount was 20 g / m ² and the Ni concentration was 13.8%.
Of Zn-Ni alloy plated steel sheet
mg / m ^2, and 25 parts of a carboxyl group-containing α, β-unsaturated monomer and 20 parts of a hydroxyl group-containing α, β-unsaturated monomer were mixed with these. Vinyl oligomer 2 consisting of 50 parts of a polymerizable monomer
0 parts and 80 parts of the epoxy resin are reacted to obtain a solid acid value of 35, and the unreacted carboxyl group is converted to 100% with triethylamine.
A neutralized form of a water-modified vinyl-modified epoxy resin was applied so as to be 0.9 g / m ² after drying.

Comparative Example 6 The adhesion amount was 20 g / m ² and the Ni concentration was 13.8%.
Of Zn-Ni alloy plated steel sheet
mg / m ² of a coating type chromate treatment, and 20 parts of a carboxyl group-containing α, β-unsaturated monomer, 20 parts of a hydroxyl group-containing α, β-unsaturated monomer, and 10 parts of a vinyl-based oligomer composed of 50 parts of a polymerizable monomer and 90 parts of an epoxy resin are obtained by reacting with a solid content acid value of 35, and
An aqueous vinyl-modified epoxy resin in which unreacted carboxyl groups in the resin were 100% neutralized with triethylamine was applied so as to have a weight of 1.4 g / m ² after drying.

Comparative Example 7 The adhesion amount was 20 g / m ² and the Ni concentration was 13.8%.
Of Zn-Ni alloy plated steel sheet
mg / m ² of a coating type chromate treatment, and 40 parts of a carboxyl group-containing α, β-unsaturated monomer, 20 parts of a hydroxyl group-containing α, β-unsaturated monomer, and 70 parts of a vinyl-based oligomer consisting of 50 parts of a polymerizable monomer and 90 parts of an epoxy resin, obtained by reacting with a solid content acid value of 15, and
An aqueous vinyl-modified epoxy resin in which unreacted carboxyl groups in the resin had been neutralized with triethylamine by 100% was applied so as to be 1.2 g / m ² after drying. It should be noted that the resin used in this example is not industrially usable because it has problems in stability after aqueous conversion.

Comparative Example 8 The adhesion amount was 20 g / m ² and the Ni concentration was 12.8%.
Of Zn-Ni alloy plated steel sheet
mg / m ^2, and 30 parts of a carboxyl group-containing α, β-unsaturated monomer and 25 parts of a hydroxyl group-containing α, β-unsaturated monomer were mixed with these. A solid-state acid value of 35 obtained by reacting 40 parts of a vinyl-based oligomer comprising 40 parts of a polymerizable monomer with 90 parts of an epoxy resin, and further comprising an unreacted carboxyl group With triethylamine to give 70
An aqueous resin composition obtained by mixing 80 parts of colloidal silica with 100 parts of a water-modified vinyl-modified epoxy resin in a 100% neutralized form was applied so as to be 1.6 g / m ² after drying.

Comparative Example 9 The adhesion amount was 20 g / m ² and the Ni concentration was 11.8%.
The amount of Cr attached to the Zn-Ni alloy plated steel sheet
mg / m ^2, and 40 parts of a carboxyl group-containing α, β-unsaturated monomer and 25 parts of a hydroxyl group-containing α, β-unsaturated monomer were mixed with these. A solid-state acid value of 35 obtained by reacting 40 parts of a vinyl-based oligomer consisting of 40 parts of a polymerizable monomer with 90 parts of an epoxy resin, and
Unreacted carboxyl groups are treated with triethylamine.
An aqueous resin composition obtained by mixing 80 parts of colloidal silica with 100 parts of a water-modified vinyl-modified epoxy resin in a 0% neutralized form was applied so as to be 1.6 g / m ² after drying. It should be noted that the resin used in this example is not industrially usable because it has problems in stability after aqueous conversion.

Comparative Example 10 The adhesion amount was 20 g / m ² and the Ni concentration was 11.8%.
Of Zn-Ni alloy plated steel sheet
mg / m ^2, and 30 parts of a carboxyl group-containing α, β-unsaturated monomer, 35 parts of a hydroxyl group-containing α, β-unsaturated monomer, and 30 parts of the same. 70 parts of a vinyl-based oligomer consisting of 50 parts of a polymerizable monomer and 25 parts of an epoxy resin, obtained by reacting the solid-state acid value of 40, and An aqueous vinyl-modified epoxy resin, in which unreacted carboxyl groups were neutralized with triethylamine by 60%, was applied so as to be 1.1 g / m ² after drying.

Comparative Example 11 The adhesion amount was 20 g / m ² and the Ni concentration was 11.8%.
Of Zn-Ni alloy plated steel sheet
mg / m ^2, and 30 parts of a carboxyl group-containing α, β-unsaturated monomer, 35 parts of a hydroxyl group-containing α, β-unsaturated monomer, and 30 parts of the same. 70 parts of a vinyl-based oligomer composed of 50 parts of a polymerizable monomer and 25 parts of an epoxy resin are reacted to obtain a solid acid value of 40, and
An aqueous liquid obtained by adding 70 parts of colloidal silica to 100 parts by weight of an aqueous vinyl-modified epoxy resin in which unreacted carboxyl groups in the resin are neutralized with triethylamine by 60% is dried. Thereafter, coating was performed so as to be 1.4 g / m ² .

Table 5 shows the characteristics of the organic composite plated steel sheets obtained for Examples 1 to 10 and Comparative Examples 1 to 11.

The evaluation method is the same as that shown in FIG. The paint adhesion is the same as in FIG. The naked corrosion resistance after processing was evaluated by the rusting state after 6000 hours of salt water spraying, and the evaluation method was the same as that in FIG. Further, the weldability is the same as in FIG.

[0100]

[Table 5]

[0101]

[Table 6]

[0102]

[Table 7]

[0103]

[Table 8]

[0104]

As described above, the organic composite plated steel sheet of the present invention is excellent in electrodeposition paintability, paint adhesion, corrosion resistance after processing and weldability.

[Brief description of the drawings]

FIG. 1: Carboxyl group-containing α,
The figure which showed the relationship between (beta) -unsaturated monomer and electrodeposition coating property.

FIG. 2: Carboxyl group-containing α,
The figure which showed the relationship between (beta) -unsaturated monomer and paint adhesion.

FIG. 3 shows the α,
The figure which showed the relationship between (beta) -unsaturated monomer and bare corrosion resistance after processing.

FIG. 4 shows the α,
The figure which showed the relationship between (beta) -unsaturated monomer and weldability.

FIG. 5 is a diagram showing the relationship between the ratio of carboxyl groups neutralized in a vinyl-modified epoxy resin and electrodeposition coating.

FIG. 6 is a view showing the relationship between the ratio of neutralized carboxyl groups in a vinyl-modified epoxy resin and paint adhesion.

FIG. 7 is a graph showing the relationship between the ratio of neutralized carboxyl groups in a vinyl-modified epoxy resin and the bare corrosion resistance after processing.

FIG. 8 is a diagram showing the relationship between the ratio of carboxyl groups neutralized in a vinyl-modified epoxy resin and weldability.

FIG. 9 is a diagram showing the relationship between hydroxyl group α, β-unsaturated monomers of a vinyl oligomer and electrodeposition coating properties.

FIG. 10 is a diagram showing the relationship between the hydroxyl group α, β-unsaturated monomer of a vinyl oligomer and paint adhesion.

FIG. 11 is a graph showing the relationship between hydroxyl group α, β-unsaturated monomers of a vinyl oligomer and bare corrosion resistance after processing.

FIG. 12 is a view showing the relationship between hydroxyl group α, β-unsaturated monomers of a vinyl oligomer and weldability.

FIG. 13 is a view showing the relationship between a monomer copolymerized with a vinyl oligomer and electrodeposition coating properties.

FIG. 14 is a view showing a relationship between a monomer copolymerized with a vinyl oligomer and paint adhesion.

FIG. 15 is a diagram showing a relationship between a monomer copolymerized with a vinyl oligomer and bare corrosion resistance after processing.

FIG. 16 is a diagram showing a relationship between a monomer copolymerizable with a vinyl oligomer and weldability.

FIG. 17 is a graph showing the relationship between the ratio of a vinyl oligomer and electrodeposition coating properties.

FIG. 18 is a graph showing the relationship between the ratio of a vinyl oligomer and paint adhesion.

FIG. 19 is a graph showing the relationship between the ratio of a vinyl oligomer and bare corrosion resistance after processing.

FIG. 20 is a graph showing the relationship between the ratio of a vinyl oligomer and weldability.

FIG. 21 is a view showing the relationship between the ratio of an epoxy resin in a vinyl-modified epoxy resin and electrodeposition coating properties.

FIG. 22 is a view showing the relationship between the proportion of epoxy resin in a vinyl-modified epoxy resin and paint adhesion.

FIG. 23 is a view showing the relationship between the ratio of epoxy resin in a vinyl-modified epoxy resin and bare corrosion resistance after processing.

FIG. 24 is a view showing the relationship between the ratio of epoxy resin in a vinyl-modified epoxy resin and weldability.

FIG. 25 is a view showing the relationship between the solid content acid value and the electrodeposition coating property of a vinyl-modified epoxy resin.

FIG. 26 is a view showing a relationship between an acid value of a solid content and paint adhesion in a vinyl-modified epoxy resin.

FIG. 27 is a graph showing the relationship between the solid content acid value of a vinyl-modified epoxy resin and the bare corrosion resistance after processing.

FIG. 28 is a graph showing the relationship between the solid content acid value and the weldability of a vinyl-modified epoxy resin.

FIG. 29 is a graph showing the relationship between the amount of colloidal silica added and electrodeposition coating properties.

FIG. 30 is a graph showing the relationship between the amount of colloidal silica added and paint adhesion.

FIG. 31 is a graph showing the relationship between the amount of colloidal silica added and the bare corrosion resistance after processing.

FIG. 32 is a graph showing the relationship between the amount of colloidal silica added and weldability.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI C08K 3/36 C08K 3/36 C09D 163/00 C09D 163/00 C23C 28/00 C23C 28/00 C (72) Inventor Kiyoshi Omori 1 Nippon Steel Corporation Hirohata Works, Hirohata-ku, Himeji-shi Nippon Steel Corporation Hirohata Works, Ltd. (56) References JP-A-7-10960 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B32B 15/08 B05D 7/14

Claims (4)

(57) [Claims] 1. A chromate-coated Zn or Zn-based alloy plated steel sheet having a Cr adhesion amount of 10 to 150 mg / m ^{2 is} coated with 15% of a carboxyl group-containing α, β-unsaturated monomer.
And 35 parts by weight of the hydroxyl group-containing α, β-unsaturated monomer.
5 to 40 parts by weight as essential components, 30 to 60 parts by weight of a vinyl oligomer containing 25 to 60 parts by weight of a monomer copolymerizable therewith, and 40 to 70 parts by weight of an epoxy resin.
And the acid value of the solid component obtained by reacting
0-vinyl-modified epoxy resin, and in which at least 40% of unreacted carboxyl groups in the modified resin have been neutralized with a basic compound, from 0.3 to 3.0 g / m
Organic composite coated steel sheet coated and dried in the range of ² . ^2. A chromate-coated Zn or Zn-based alloy plated steel sheet having a Cr adhesion amount of 10 to 150 mg / m ^{2 is} coated with a carboxyl group-containing α, β-unsaturated monomer.
And 35 parts by weight of the hydroxyl group-containing α, β-unsaturated monomer.
5 to 40 parts by weight as essential components, 30 to 60 parts by weight of a vinyl oligomer containing 25 to 60 parts by weight of a monomer copolymerizable therewith, and 40 to 70 parts by weight of an epoxy resin.
And the acid value of the solid component obtained by reacting
0, a vinyl-modified epoxy resin in which at least 40% of unreacted carboxyl groups in the modified resin have been neutralized with a basic compound, an amino resin, a blocked isocyanate compound, an epoxy compound, an azirine An organic composite plated steel sheet comprising a resin composition to which one or more curing agents such as a compound and a melamine resin are added in a range of 0.3 to 3.0 g / m ² and dried. 3. A chromate-coated Zn or Zn-based alloy plated steel sheet having a Cr adhesion amount of 10 to 150 mg / m ^{2 is} coated with a carboxyl group-containing α, β-unsaturated monomer.
And 35 parts by weight of the hydroxyl group-containing α, β-unsaturated monomer.
5 to 40 parts by weight as essential components, 30 to 60 parts by weight of a vinyl oligomer containing 25 to 60 parts by weight of a monomer copolymerizable therewith, and 40 to 70 parts by weight of an epoxy resin.
And the acid value of the solid component obtained by reacting
0 to 100% by weight of a resin in which 40% or more of the unreacted carboxyl groups in the modified resin are neutralized with a basic compound, and 10 to 60 parts by weight of colloidal silica or aerosil. An organic composite plated steel sheet obtained by coating and drying a resin composition blended in parts by weight in the range of 0.3 to 3.0 g / m ² . 4. A chromate-coated Zn or Zn-based alloy plated steel sheet having a Cr adhesion amount of 10 to 150 mg / m ^{2 is} coated with a carboxyl group-containing α, β-unsaturated monomer.
And 35 parts by weight of the hydroxyl group-containing α, β-unsaturated monomer.
5 to 40 parts by weight as essential components, 30 to 60 parts by weight of a vinyl oligomer containing 25 to 60 parts by weight of a monomer copolymerizable therewith, and 40 to 70 parts by weight of an epoxy resin.
And the acid value of the solid component obtained by reacting
0 to 100 parts by weight of a resin obtained by neutralizing 40% or more of the unreacted carboxyl groups in the modified resin with a basic compound, and adding 10 to 60 parts of colloidal silica or aerosil to the resin. Parts by weight, and further added one or more curing agents such as an amino resin, a blocked isocyanate compound, an epoxy compound, an azirine compound, and a melamine resin. the organic composite plated steel sheet formed by coating in the range of m ^2.