JPH0641570B2 - Cationic electrodeposition coating composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a cationic electrodeposition coating composition having excellent anticorrosion properties for metals, and more particularly, a cationic electrodeposition coating composition having particularly excellent anticorrosion properties for metal edges. It is about.

2. Description of the Related Art Cationic electrodeposition paints are paints with excellent finish and corrosion resistance, and can be applied to the inner surface of structures, and are therefore widely applied to the automobile industry, which has many bag structures.
However, the corrosion from the end of the cut or punched hole of the material cannot be solved, and for example, the rust prevention at this end is currently dealt with by applying one by one an organic sealer with a plasticizer added to vinyl chloride. .

However, it is structurally difficult to apply and requires a great number of steps.

On the other hand, a conventional rust preventive paint has been proposed which contains a condensed phosphate and a substance containing zinc sulfide (JP-A-58-1).
32047). This technology proposes that condensed phosphate and zinc sulfide are additively effective in preventing rust, but when condensed phosphate is used in electrodeposition paint, the cut part or punched hole of the material It does not suggest that the edge of metal such as can be uniformly coated.

Problems to be Solved by the Present Invention As described above, the conventional cationic electrodeposition coating material has a cut portion of the material,
The coating on the end of the punched hole was not always sufficient, and the corrosion from that part was a problem.

A first object of the present invention is to provide an electrodeposition coating composition which is excellent in coatability on the edge of a metal such as a cut portion and a punched hole of a material.

Means for Solving the Problems The present invention solves the above problems by incorporating a condensed phosphate pigment into a cationic electrodeposition coating composition to improve the coating property of the coating material on the edge of the metal.

That is, in the present invention, in a coating composition containing 10 to 20 parts by volume of a pigment with respect to 100 parts by volume of resin (as calculated as solid content), the pigment is a condensed phosphate pigment that is poorly soluble in water.
The present invention relates to a cationic electrodeposition coating composition containing 10 to 10% by volume.

The resin component of the cationic electrodeposition coating used in the present invention,
It is not particularly limited as long as it is a resin usually used for cationic electrodeposition. These cationic electrodeposition resins are disclosed in, for example, JP-A-49-99337 and JP-A-51-12.
6225, JP-A-51-103135, JP-A-51-117799, and JP-A-52-1874.
6, JP-A-52-87498, JP-A-53.
-43800, JP-A-53-65327,
JP-A-53-65329, JP-A-47-759, JP-A-48-51924, JP-A-52-1
1228, JP-A-54-15936, JP-A-54-93024, JP-A-55-31889, JP-A-55-31890, and JP-A-56-4.
9725, JP-A-56-79163, JP-A-57-1126873, JP-A-57-1391.
47, JP-A-54-97632 and JP-A-55-137174.

The resin used in the present invention may be any of these resins, but is particularly preferably a cationic resin obtained by reacting an epoxy resin with a compound having an amino group. Of course, it is not limited to this, and may be a phenol resin having a cation group, a polybutadiene resin, an acrylonitrile resin, a styrene resin, a malein diene compound resin, or a copolymer resin thereof.

To achieve the object of the present invention, the resin component (solid content) 1
10 to 20 parts by volume of the pigment component are mixed with 100 parts by volume,
Containing 4 to 10% by volume of condensed phosphate pigment in the pigment component. If the amount of the pigment component is less than 10 parts by volume, there is no rust-preventing effect on the end of the metal for the purpose, and if it exceeds 20 parts by volume, the pigment tends to settle, although the desired effect of the present invention is exhibited, and the coated plate on a horizontal surface. In, there is a problem that it is difficult to obtain a smooth coated surface. Further, if the condensed phosphate pigment in the pigment component is less than 4% by volume, there is no rust preventive effect on the end portion of the target metal,
On the other hand, if it exceeds 10% by volume, it is impossible to obtain more than the effect intended by the present invention.

The condensed phosphate pigment used in the present invention is a condensed phosphate which is poorly soluble in water (solubility of 0.5 or less), such as tripolyphosphoric acid,
Divalent or trivalent metal salts such as metaphosphoric acid and pyrophosphoric acid, for example, aluminum, ferric iron, titanium, zirconium, manganese, molybdenum, cobalt, nickel, copper,
It is a salt of zinc, silicon or the like, and an aluminum salt is particularly preferable. Specifically, aluminum dihydrogen tripolyphosphate,
Aluminum metaphosphate, ferric pyrophosphate and the like are exemplified as particularly preferable ones. These condensed phosphate pigments may be treated appropriately to reduce their water-soluble components and improve their stability in water.

The average particle size of the condensed phosphate pigment is 1 to 30 μm, especially 1 to 30 μm.
10 μm is preferable.

As other pigments, titanium oxide, carbon black, zinc white, iron oxide, precipitating barium carbonate, barium sulfate, calcium carbonate, lead silicate, lead oxide, strontium chromate, etc., which are commonly used for cationic electrodeposition, are appropriately used. You can use it.

In the invention of the present application, when the flaky pigment is used in combination with the condensed phosphate pigment, the effect of hiding the edges is further improved. Examples of the scaly pigment include mica, aluminum powder, talc, aluminum silicate, graphite and the like, and one kind or two or more kinds may be used. The amount is 10 to 96% by volume in the pigment component
When the content is less than 10% by volume, the effect of using the flaky pigment is small.

The term "scaly pigment" as used herein refers to a pigment having a thickness of 1/10 or less with respect to the minimum plane length, and the capacity means a weight of resin / specific gravity of resin and a weight of pigment / true specific gravity of pigment. ,
These pigments may be adjusted to 20 μm or less, preferably 10 μm or less, together with a dispersion vehicle obtained by neutralizing a cation resin, for example, an amino-modified epoxy resin with acetic acid, using a conventional ball mill, sand mill, claulus disperser, continuous disperser, or the like. .

The metal material to which the method of the present invention can be applied may be a metal that is conventionally generally electrodeposited, such as iron, steel, galvanized steel, alloys thereof, etc., or may be a chemical conversion treated material.

EFFECT OF THE INVENTION The properties of the coating film obtained by using the electrodeposition coating composition according to the present invention are higher than the properties of the coating film obtained from the conventionally used cationic electrodeposition coating composition after baking. In terms of film appearance, quality, and corrosion resistance on flat plates, it is not inferior to the others, and the corrosion resistance at the edges of the metal can surpass the latter.

The present invention will be described below with reference to examples, but the present invention is not limited thereto.

Example 1 Method for Preparing Cationic Electrodeposition Coating Composition: [Resin I] 1000 parts by weight of diglycidyl ether of bisphenol A (epoxy equivalent 910) was added to 463 parts by weight of ethylene glycol monoethyl ether while maintaining at 70 ° C. under stirring. After dissolution, 80.3 parts by weight of diethylamine was added and the mixture was reacted at 100 ° C. for 2 hours to prepare an amine epoxy adduct (component A).

On the other hand, Coronate L (polyisocyanate manufactured by Nippon Polyurethane Industry Co., Ltd .; NCO 13%, nonvolatile content 75% by weight) 8
Dibutyltin laurate 0.05 parts by weight was added to 75 parts by weight,
It heated at 50 degreeC and 390 weight part of 2-ethylhexanol was added, and after that, it was made to react at 120 degreeC for 90 minutes. The obtained reaction product was diluted with 130 parts by weight of ethylene glycol monoethyl ether (component B).

A mixture of 1000 parts by weight of component A and 400 parts by weight of component B was neutralized with 30 parts by weight of glacial acetic acid and then diluted with 570 parts by weight of deionized water to prepare a resin having a nonvolatile content of 50% by weight.

[Resin II] 150 parts by weight of Resin I was mixed with 0.8 parts by weight of glacial acetic acid to prepare Resin II having a nonvolatile content of 50% by weight.

[Pigment paste I] Titanium oxide 397.6 parts by weight (94.7 parts by volume; true specific gravity 4.20) Carbon black 11.8 parts by weight (6.2 parts by volume; true specific gravity 1.90) Lead silicate 26.2 parts by weight (4.1 parts by volume; true specific gravity 6.40) Tripolyphosphate Aluminum 12.7 parts by weight (4.4 parts by volume; true specific gravity 2.90) 193.7 parts by weight of Resin II (83.5 parts by volume of resin component, specific gravity 1.16) and 349.2 parts by weight of deionized water are added to the above mixture,
After stirring at low speed for 15 minutes, glass beads were added and dispersed with a high speed disperser for 3 hours to prepare a pigment paste I having a nonvolatile content of 55% by weight.

Method for preparing cationic electrodeposition paint: Resin I 200.2 parts by weight (resin component 86.3 parts by volume), Pigment Paste I 163.1 parts by weight (resin component 13.7 parts by volume, pigment component 18.0 parts by volume, among them, aluminum tripolyphosphate 4
%), 2.4 parts by weight of dibutyltin laurate and 583.3 parts by weight of deionized water to prepare a cationic electrodeposition coating composition.

Manufacturing method of metal end plate (edge part): Using a commercially available cold-rolled steel plate of 70 × 150 × 0.8 mm, as shown in FIG. 1, a sandpaper (100
No. 0) (2) is attached, this is fixed to the support base (3), the test steel plate (4) is attached to the fixture (5) having the inclination angles (θ) of 60 ° and 90 °, and the end is attached. The parts were ground at 60 ° and 90 ° angles. Then, a usual immersion type zinc phosphate chemical conversion treatment was performed.

An applied voltage of 200 is applied to the steel sheet using the above cationic electrodeposition coating
V, paint a 20μ film in 3 minutes, wash with water, and then at 180 ℃ for 30 minutes
Baked for minutes. Table 1 shows the salt spray test (JIS Z-2371) results of the coating film using this coated plate as a test plate.

Example 2 [Pigment paste II] Titanium oxide 397.6 parts by weight (94.7 parts by volume) Carbon black 11.8 parts by weight (6.2 parts by volume) Lead silicate 26.2 parts by weight (4.1 parts by volume) Aluminum metaphosphate 33.8 parts by weight (11.7 parts by volume) 193.7 parts by weight of Resin II (83.5 parts by volume of resin component) and 366.4 parts by weight of deionized water were added to the mixture, and Example 1 was added.
A pigment paste II was prepared in the same manner as in.

Method for preparing cationic electrodeposition paint: Resin I 202.1 parts by weight (resin component 87.1 parts by volume), Pigment Paste II 158.8 parts by weight (resin component 12.9 parts by volume, pigment component 1)
8.0 parts by volume, of which 10% by volume of aluminum metaphosphate), 2.4 parts by weight of dibutyltin laurate and 578.7 parts by weight of deionized water were added to prepare a cationic electrodeposition coating composition.

A plate electrodeposited by the same method using the same metal plate as in Example 1 was used as a test plate. The test results of this coating film are shown in Table 1.

Example 3 [Pigment paste III] Titanium oxide 397.6 parts by weight (94.7 parts by volume) Carbon black 11.8 parts by weight (6.2 parts by volume) Lead silicate 26.2 parts by weight (4.1 parts by volume) Aluminum tripolyphosphate 21.8 parts by weight (7.5 parts by volume) 37.5 parts by weight of mica (12.5 parts by volume; true specific gravity of 3.00) were mixed, and this mixture was mixed with 209.6 parts by weight of resin II (resin component).
(90.3 parts by volume) and 385.9 parts by weight of deionized water were added to prepare a pigment paste III in the same manner as in Example 1.

Method for preparing cationic electrodeposition coating: Resin I 206.9 parts by weight (resin component 89.2 parts by volume), Pigment Paste II 130.8 parts by weight (resin component 10.8 parts by volume, pigment component 1)
5.0 parts by volume, of which 6% by volume aluminum tripolyphosphate, 10% by volume scale pigment), dibutyltin laurate 2.
4 parts by weight and 536.6 parts by weight of deionized water were mixed to prepare a cationic electrodeposition coating composition.

The same metal plate as in Example 1 was electrodeposited. The test results of this coated plate are shown in Table 1.

Example 4 [Pigment paste IV] Titanium oxide 36.5 parts by weight (8.7 parts by volume) Carbon black 1.9 parts by weight (1.0 parts by volume) Lead silicate 27.5 parts by weight (4.3 parts by volume) Aluminum silicate 206.4 parts by weight (80.0 parts by volume; True specific gravity 2.58) 17.4 parts by weight of aluminum tripolyphosphate (6.0 parts by weight) 173.8 parts by weight of Resin II (74.9 parts by volume of resin component) and 321.1 parts by weight of deionized water were added to the above-mentioned formulation mixture, and Example 1 was added.
A pigment paste IV having a nonvolatile content of 48% by weight was prepared in the same manner as in.

Method for preparing cationic electrodeposition paint: Resin I 214.6 parts by weight (resin component 92.5 parts by volume), Pigment Paste IV 78.6 parts by weight (resin component 7.5 parts by volume, pigment component 10.0)
Volume part, of which aluminum tripolyphosphate 6% by volume,
A scaly pigment (80% by volume), dibutyltin laurate (2.4 parts by weight) and deionized water (441 parts by weight) were mixed to prepare a cationic electrodeposition coating composition.

The same metal plate as in Example 1 was electrodeposited, and the test results of this coated plate are shown in Table 1.

Comparative Example 1 Using the same pigment paste 1 as in Example 1, resin I217.8 parts by weight (resin component 93.9 parts by volume), pigment paste 72.5 parts by weight (resin component 6.1 parts by volume, pigment component 8.0 parts by volume, among them, tripolyphosphorus) (4% by volume of aluminum acid salt), 2.4 parts by weight of dibutyltin laurate and 451.1 parts by weight of deionized water were mixed to prepare a cationic electrodeposition coating composition.

The same metal plate as in Example 1 was electrodeposited. The test results of this coated plate are shown in Table 1.

Comparative Example 2 [Pigment paste V] Titanium oxide 397.6 parts by weight (94.7 parts by volume) Carbon black 11.8 parts by weight (6.2 parts by volume) Lead silicate 26.2 parts by weight (4.1 parts by volume) Resin II 193.7 parts by weight (resin Ingredients 83.5 parts by volume) and deionized water 338.8 parts by weight were added and Example 1
A pigment paste V having a nonvolatile content of 55% by weight was prepared in the same manner as in.

Method for preparing cationic electrodeposition coating: resin I 204.4 parts by weight (resin component 88.1 parts by volume), pigment paste V138.3 parts by weight (resin component 11.9 parts by volume, pigment component 15.
0 parts by volume), 2.4 parts by weight of dibutyltin laurate and 546.2 parts by weight of deionized water were added to prepare a cationic electrodeposition coating composition.

The same metal plate as in Example 1 was electrodeposited. The test results of this coated plate are shown in Table 1.

[Brief description of drawings]

FIG. 1 is a view showing a means for polishing an end portion of a metal plate in the embodiment. (1) glass plate, (2) sandpaper, (3) support, (4) metal plate, (5) holder.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-57-2370 (JP, A) JP-A-50-91631 (JP, A) JP-A-53-59725 (JP, A) JP-A-58- 132047 (JP, A)

Claims (4)

[Claims] 1. To 100 parts by volume of resin (as solid content),
In a coating composition containing 10 to 20 parts by volume of a pigment,
The pigment is a condensed phosphate pigment that is poorly soluble in water,
A cationic electrodeposition coating composition containing 0% by volume. 2. A composition according to claim 1, wherein the condensed phosphate pigment is condensed aluminum phosphate. 3. The composition according to claim 1, wherein the pigment contains 10 to 96% by volume of a scaly pigment. 4. The scale-like pigment is mica, aluminum powder,
The composition of claim 3 selected from the group consisting of talc, aluminum silicate, and graphite.