WO2002064857A1

WO2002064857A1 - Treating agent for metal surface, method of treating metal surface, and surface-treated metallic material

Info

Publication number: WO2002064857A1
Application number: PCT/JP2002/001215
Authority: WO
Inventors: Motohiro Sasaki; Koichi Saito
Original assignee: Nippon Paint Co., Ltd.
Priority date: 2001-02-14
Filing date: 2002-02-14
Publication date: 2002-08-22
Also published as: JP2002241670A

Abstract

A treating agent for metal surfaces which gives a coating film excellent in conductivity and corrosion resistance and in adhesion to topcoat films to be formed thereon. The treating agent comprises an aqueous dispersion obtained by reacting an epoxy compound with an ionomer resin in an aqueous dispersion form obtained from an ethylene/unsaturated carboxylic acid copolymer containing 10 to 30 wt.% unsaturated carboxylic acid units by neutralizing at least 30% of the carboxyl groups of the copolymer with potassium ions.

Description

Specification

Metal surface treatment agent, metal surface treatment method and surface treated metal material

The present invention relates to a metal surface treatment agent, a metal surface treatment method, and a surface treatment metal material, and more particularly to a metal surface treatment agent containing an ionomer resin-based aqueous dispersion. Background art

Organic composite coated steel sheets widely used for home appliances, office equipment, building materials, automobiles, etc. have excellent corrosion resistance. The organic composite coated steel sheet has been widely put into practical use as a high-performance steel sheet provided with paint adhesion, fingerprint resistance, lubricity, etc., depending on the application.

Here, the organic composite coated steel sheet refers to a steel sheet having a surface subjected to chromate treatment and further having a thin organic resin skin formed on the surface.

Conventionally, as one of the methods for forming an organic resin film of an organic composite coated steel sheet, a method using an aqueous dispersion of an ionomer resin obtained by neutralizing ethylene and an unsaturated sulfonic acid copolymer with metal ions has been known. I have.

This ionomer resin has good adhesion to various base materials, especially metals, and the formed film is tough and resistant to scratches, and is resistant to organic solvents such as ethanol and methyl ethyl ketone. Is an excellent material.

In addition, an aqueous dispersion composition based on an ionomer resin and formed by mixing a polyvalent epoxy compound at a temperature of 50 ° C. or lower has been proposed (Japanese Patent Application Laid-Open No. HEI 4-131478). No.). Furthermore, a metal surface protection agent containing three components, an ionomer resin neutralized with a divalent metal such as magnesium and zinc, an epoxy group-containing compound, and an ionomer resin and an epoxy group-containing compound, is also available. It has been proposed (Japanese Patent Laid-Open No. 117-1736). Summary of the Invention

The ionomer resin or the ionomer resin based on A film formed with the composition described above has insufficient conductivity when the film thickness is large, and when coating with a top coat, it is not always possible to obtain good coating adhesion. The present invention has been made in view of the above problems, and has excellent conductivity of a film when used as a surface treatment agent, and excellent coating adhesion when a topcoat film is formed on the film. An object of the present invention is to provide a metal surface treatment agent, a metal surface treatment method, and a surface treated metal material.

The present inventors have conducted intensive studies on the above problems, and as a result, have reached the following present invention.

1. An ionomer resin in which 30% or more of the carboxyl groups of an ethylene-unsaturated carboxylic acid copolymer containing 10 to 30% by mass of unsaturated sum carboxylic acid is neutralized with potassium ion and dispersed in water, and A metal surface treatment agent comprising an aqueous dispersion resin obtained by reacting with an epoxy compound.

2. A metal surface treating agent comprising a composite aqueous dispersion resin obtained by radical polymerization of an unsaturated monomer in the presence of the above aqueous dispersion resin.

3. A metal surface treatment agent comprising a mixture of the above aqueous dispersion resin or composite aqueous dispersion resin with at least one aqueous resin selected from the group consisting of an aqueous polyurethane resin, an aqueous polyester resin, and an aqueous acryl 'resin. .

4. A composite aqueous dispersion obtained by radical polymerization of an unsaturated monomer in a mixture of the above aqueous dispersion resin and at least one aqueous resin selected from an aqueous polyurethane resin, an aqueous polyester resin, and an aqueous acryl resin. A metal surface treatment agent comprising a resin mixture.

5. The metal surface treating agent as described above, further comprising fine particles of silicic acid.

6. A metal surface treatment method, which comprises applying the metal surface treatment agent to a metal surface to form a film.

7. The metal surface treatment method as described above, further comprising applying a top coat on the film to form a coating film.

8. Surface treated metal material obtained by the above metal surface treatment method. Detailed Disclosure of the Invention

Hereinafter, the present invention will be described in detail. The metal surface treating agent of the present invention has an unsaturated carboxylic acid of 10 to 30 mass. /. Aqueous dispersion obtained by neutralizing 30% or more of the carboxyl 'groups of the contained ethylene-unsaturated carboxylic acid copolymer with force rimion, and reacting the ionomer resin water-dispersed with the epoxy compound. Including resin.

Examples of the unsaturated carboxylic acid of the present invention include atrialic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid and the like, and acrylic acid and methacrylic acid are particularly preferable.

The ionomer resin of the present invention uses potassium as an ion source. When the ion source is another monovalent ion, for example, sodium, the formed film has insufficient conductivity. Similarly, when the ion source is a divalent ion, for example, zinc or magnesium, the conductivity is not sufficient.

Further, the ionomer resin of the present invention has a neutrality of carboxyl groups due to potassium ions of 30% or more. When the degree of neutralization is less than 30%, the conductivity is not sufficient, and when the degree of neutralization is extremely low, the solvent resistance decreases. On the other hand, the upper limit of the degree of neutralization is not particularly limited, but is preferably 100% or less from the viewpoint of corrosion resistance.

In the present invention, the aqueous dispersion of the ionomer resin is reacted with an epoxy compound to form an aqueous dispersion resin, and a metal surface treating agent containing the aqueous dispersion resin is obtained. Here, the epoxy compound refers to a compound having at least one epoxy group in one molecule, and includes glycidyl ethers and glycidyl esters. Glycidyl ethers include, for example, phenyl glycidyl ether, resole / syndiglycidyl ether, bisphenol / diglycidyl ether, glycerin polyglycidyl ether, trimethylolpropane polyglycidyl ether, pentaerythritol polyglycidyl ether One tel and the like. Examples of the glycidyl esters include diglycidyl adipate and diglycidyl phthalate.

The reaction between the ionomer resin and the epoxy compound is carried out at a temperature in the range of 30 ° C. to the boiling point, more preferably at a temperature in the range of 60 to 95 ° C. When the temperature is lower than 30 ° C, the reaction does not proceed sufficiently. The reaction time is 0.5 to 10 hours. The above metal surface treatment agent has excellent conductivity of a film when used as a surface treatment agent, and also has excellent coating adhesion when a top coat is formed on the film.

Further, the metal surface treating agent thus obtained can be further compounded or blended with another resin in the aqueous dispersion resin.

That is, a composite aqueous dispersion resin of an ionomer-based aqueous dispersion resin and an acryl resin can be obtained by subjecting an unsaturated monomer to radical polymerization using an initiator in the presence of the aqueous dispersion resin.

Further, at least one water-based resin selected from water-based polyurethane resin, water-based polyester resin and water-based acrylic resin may be further added to the water-based dispersion resin or the composite water-based dispersion resin.

In addition, the unsaturated monomer is subjected to radical polymerization in a mixture of the above aqueous dispersion resin and at least one aqueous resin selected from an aqueous polyurethane resin, an aqueous polyester resin, and an aqueous acryl resin to form a composite aqueous dispersion resin mixture. Is also good.

Here, as the unsaturated monomer, alkyl (meth) acrylates, styrene, (meth) acrylic acid, hydroxyalkyl (meth) acrylates and the like can be used.

As the polymerization initiator, persulfates such as potassium persulfate and ammonium persulfate, and azo compounds such as azobiscyanovaleric acid and azobisisobutyronitrile can be used.

The aqueous polyurethane resin is prepared, for example, by reacting a diol with a diisocyanate compound such as hexamethylene diisocyanate, isophorone diisocyanate, or tolylene diisocyanate, and further elongating the chain with diamine or the like to disperse in water. Can be obtained.

The aqueous polyester resin can be obtained by, for example, dehydrating and condensing a diol and a polybasic acid, neutralizing the resultant with an amine or the like, and making it water-soluble or water-dispersed. The aqueous acrylic resin is prepared, for example, by radically polymerizing an unsaturated monomer containing an unsaturated carboxylic acid in an organic solvent, and then neutralizing the radical with an amine or the like to make it water-soluble or dispersed in water. Emulsion polymerization of unsaturated monomers Therefore, it can be obtained.

The above composite or other resin to be compounded is 50% by mass with respect to the aqueous dispersion resin before the composite or compound. / ₀ or less, more preferably 30 mass. Use in the range of / ₀ or less.

The metal surface treating agent obtained as described above can improve the corrosion resistance of a film when used as a surface treating agent. The combined or compounded amount is 50 mass. If it exceeds / ₀ , the effect of improving the conductivity of the obtained metal surface treating agent will be impaired.

The radical polymerization conditions for obtaining the composite aqueous dispersion are a reaction temperature of 40 to 90 ° C. and a reaction time of 0.5 to 10 hours.

More preferably, the metal surface treating agent of the present invention is obtained by further mixing fine particles of silicic acid with the aqueous dispersion resin or the composite aqueous dispersion resin.

Here, the silica fine particles are not particularly limited, but, for example, those having an average particle size of about 0.01 to 0.5 m are suitable, and are appropriately selected from colloidal silica, fumed silica, and the like. be able to. It is preferable that the silica fine particles be blended in an amount of 10 to 50% by mass based on the total amount of all the aqueous resins blended. By blending the fine particles, the corrosion resistance of the metal material surface-treated with the metal surface treating agent can be improved.

In the metal surface treatment method of the present invention, the above-mentioned metal surface treatment agent is applied to a metal surface to form a film. The coating method is not particularly limited, and a normal coating method such as a roll coating method, a spraying method, and a dipping method can be used.

The film formed by the above metal surface treatment method has excellent conductivity and corrosion resistance, and also has excellent solvent resistance.

Further, in the metal surface treatment method of the present invention, a top coat is applied on the above-mentioned film to form a coated film. The coating method is not particularly limited, and a normal coating method such as a roll coating method, a spray method, and a dipping method can be used.

The surface-treated metal material obtained by the above-described metal surface treatment method has excellent coating adhesion of the topcoat. BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be further described with reference to Examples and Comparative Examples. The present invention is not limited to the embodiments described below.

(Preparation of metal surface treatment agent)

As shown in Table 1, the following materials were used for the metal surface treatment agent.

Unsaturated monomer 2HEMA: 2-hydroxy: nithyl methacrylate

EGDM: Ethylene Grunyl Dimetharate

Note a "t Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Prima Konore 59801 100 50 100 Nikurenole 2060 100 100

Potassium hydroxide 9.3 4.7 2.6

Sodium hydroxide 5.6

Of ionomer resin

Manufacture of aqueous dispersion Zinc oxide 4.5

25% ammonia water 15.8.15.1 Deionized water 375 188 344 363 351 351 Solid content 22 22 22 22 22 Metal neutralization rate 60 60 20 60 40 Denacol 313 L.5

Epoxy compound

Denacol 321

reaction

Epicort 828

HUX-320 156 with polyurethane

Styrene

Methizole methacrylate

Butyl acrylate

Unsaturated monomer-methacrylic acid

Polymerization

2HEMA

EGDM

1% KPS aqueous solution

Add silica particles Snowtex N 150 150 150 150 150 Deionized water 48 107 55 55 55 Adjust solid content

Solids% 20 20 20 20 20 Unsaturated monomer 2HEMA: 2-hydroxyethyl methacrylate

EGDM: Ethylene glycol dimethacrylate

8

The metal surface treating agents of Examples and Comparative Examples were Primacol 59801 (Dow Chemical's atrialic acid content: 20% by mass) or ethylene-methacrylic acid as an ethylene-acrylic acid copolymer. As the copolymer, 2 Utrell 206 (Mitsui's DuPont Polychemical Co., Ltd., methacrylic acid content: 20% by mass) was used.

Potassium hydroxide was used as a potassium ion source in the examples. In addition, as a metal ion source of a comparative example, sodium hydroxide was used as a monovalent sodium ion source, and zinc oxide was used as a divalent zinc ion source. In some Examples and Comparative Examples, ammonia, which is a volatile neutralizer, was used in combination with a metal ion source or used instead of a metal ion source.

Epoxy compounds of the examples include denacol 313 (glycerin polyglycidyl-ter Nagase Kasei Kogyo), denacol 321 (trimethylolpropane polyglycidyl mono-ter Nagase Kasei Kogyo), or Epikote 828 (bisphene). Nord A diglycidyl ether (made by Yuka Shell Epoxy)).

As the aqueous polyurethane resin, Adekabon Titer HU X-320 (manufactured by Asahi Denka Kogyo) was used.

The unsaturated monomers used in forming the composite aqueous dispersion were those shown in Table 1. Here, KPS is potassium persulfate as a polymerization initiator.

As the silica fine particles to be blended in several embodiments, the 1 0 to 2 0 nm colloidal silica particle size, as a solid content 2 0 mass ^_0/0 containing Snowtex N (manufactured by Nissan Chemical Industries) Using.

The preparation method of the metal surface treating agent using each of the above-mentioned raw materials was based on the following method. In a flask equipped with a stirrer, a temperature controller, a dropping funnel, a nitrogen inlet tube, and a cooler, a predetermined amount of ethylene- (meth) acrylic acid copolymer set in each of the examples and comparative examples, and a predetermined amount of A metal ion source, a predetermined amount of 25% by mass ammonia water for some examples and comparative examples, and a slightly different amount of deionized water for each example and comparative example were charged and stirred. It was kept at a temperature of ° C for 2 hours. Thereafter, the mixture was cooled with water to obtain an aqueous dispersion having a different neutralization ratio for each of Examples and Comparative Examples. The solids content of this aqueous dispersion was previously adjusted to a slightly different amount for each Example or Comparative Example. 9

By setting, it is uniformly adjusted to 22% by mass in all of Examples and Comparative Examples.

A predetermined amount of the epoxy compound set in each Example and Comparative Example was added to the above aqueous dispersion, and the mixture was maintained at a temperature of 85 ° C for 2 hours with stirring to complete the reaction. Obtained.

In Example 2, an aqueous polyurethane resin was further added to the aqueous dispersion resin. In Example 3, an unsaturated monomer was polymerized in the presence of the aqueous dispersion resin. In Example 4, an unsaturated monomer was polymerized in a mixture of the aqueous dispersion resin and the aqueous polyurethane resin.

Polymerization of the unsaturated monomer was performed as follows. First, half of the value of the unsaturated monomer shown in Table 1 was poured into a flask containing an aqueous dispersion resin maintained at 80 ° C with stirring, and after 10 minutes, a 1% aqueous solution of potassium persulfate was added. The reaction was started by feeding 2 Z 3 of the numerical value shown in Table 1. After a further 10 minutes, the remaining unsaturated monomer was added, and then, after a further 10 minutes, the remaining 1% aqueous persulfuric acid aqueous solution was added, and then the temperature was maintained at 80 ° C for 2 hours. The reaction was completed.

To the obtained aqueous dispersion resin or composite aqueous dispersion resin, predetermined amounts of colloidal silica and deionized water set in each of Examples and Comparative Examples were added to uniformly adjust the solid content to 20% by mass. A metal surface treatment agent was obtained.

Table 1 shows specific raw material mixing conditions of each of Examples 1 to 6 and Comparative Examples 1 to 5 for the metal surface treating agent.

(Preparation of surface treated metal material)

As shown in Tables 2 and 3, as the metal material to which the metal surface treating agent of each of the above Examples and Comparative Examples is applied, EG (Electro Galvanized Steel Sheet), GI (Hot Dipped Galvanized Steel Sheet) and GL ( Three types of steel sheets were used: molten zinc-aluminum alloy coated steel sheets. Note that the three types of steel plates used had dimensions of 7 Omm X 15 Omm X 0.8 mm manufactured by Japan Test Panel. . I

to ο

"EG" in steel sheet type indicates steel sheet with electro-zinc plating

“GI” in the steel sheet type indicates a steel sheet coated with molten zinc.

“GL” in the steel sheet type indicates a steel sheet coated with a molten zinc aluminum alloy.

Paint adhesion: cross-cut Z processing part / eyes + processing part

o k- O null Gold tH] Conductivity Solvent resistance

NO. Steel sheet type Corrosion resistance Paint adhesion

Processing | J Ω Ethanore Kerosene

A EG Comparative Example 1 0.5 10 ◎ 1/1/1

00 B EG Comparative Example 2 2. 8 9 Δ 〇 10/10/9

〇 “Ya

C EG Comparative Example 3 2. 4 10 o 〇 10/10/9

,

OQ V D EG Comparative Example 4 2. 8 10

\ Side ◎ ◎ 10/9/9

Mil.

Separated E EG Comparative Example 5 3. 4 10 〇〇 10/8/7

Reason

A. F GI Comparative Example 1 0.6.10 ◎ ◎ 1/1/1

Γ * G GI Comparative Example 2 2. 7 9 Δ 〇 10/10/9

T3 material

-H GI Comparative Example 3 2. 5 10 〇〇 10/10/9

ί fee

I Tan ratio I GI Comparative example 4 2. 9 10

A Factory ◎ ◎ 10/9/9

J GI Comparative Example 5 3. 6 10 〇〇 10/9/7

1 0 Example

t K GL Comparative Example 1 0.6 10 ◎ 1/1/1

L GL Comparative Example 2 3.09

n △ 〇 10/10/9

τ U-r M GL Comparative Example 3 2. 5 10 〇〇 10/10/9

Γ NGL Comparative Example 4 2. 4 10

◎ ◎ ◎ 10/9/9 BU O GL Comparative Example 5 3.2 10 〇〇 10/9/7 u,

"EG" in steel sheet type indicates steel sheet with electro-zinc plating

i¾

r “GL” in the steel sheet type indicates a steel sheet coated with a molten zinc aluminum alloy.

Paint adhesion: cross cut + processing

12

Example Apply a point-to-point point metal surface treatment agent using a bar coater # 3 so that the film thickness after drying is 1 μm, and bake dry until the steel sheet reaches a temperature of 150 ° C. Then, a film was formed, and a test plate for evaluating conductivity, corrosion resistance, and solvent resistance described below was obtained. Further, a super coat 100 (Melamine alkyd paint manufactured by Nippon Paint) was further applied to the above test material using a bar coater # 32 as a top coat paint so that the film thickness after drying became 2; The coating was formed by baking and drying at 50 ° C for 20 minutes to obtain a test plate for evaluating the overcoat adhesion described later.

Evaluate the conductivity, corrosion resistance, and solvent resistance of the coatings of Examples A to R and Comparative Examples A to について for the surface-treated metal materials obtained by the above preparation methods, and evaluate the coating adhesion of the overcoat film. The results are shown in Tables 2 and 3.

(Performance evaluation)

The evaluation method was based on the following methods.

First, the evaluation of the film will be described.

The conductivity of the coating was evaluated by measuring the surface resistance (unit: Ω) of the test material using Loresta (Mitsubishi Chemical surface resistance measuring device). Therefore, the smaller the value, the better the conductivity. The numerical values in Tables 2 and 3 used the average of 10 measurements. The corrosion resistance of the film was evaluated by spraying a 5% saline solution at 35 ° C while sealing the end face and the back face of the test material, and evaluating the white area generation area rate after 240 hours out of 10 points. The evaluation criteria are as follows.

10 points: no white 鲭

Less than 5% white area

5% or more and less than 10%

10% or more and less than 20%

20% or more and less than 30%

30% or more and less than 40%

40% or more and less than 50%

50% or more and less than 70%

70% or more and less than 90% 13

1 point: 90% or more

Solvent resistance of the film, after the test plate after installation in a rubbing tester, a gauze impregnated with ethanol 0. 5 K g ί ζ 'is pressed against the test plate with a load of cm ² by reciprocating 1 0 times The state of the film on the surface of the test plate was observed. Kerosene was also performed in the same manner as above except that the number of round trips was changed to 50 times. The evaluation criteria are as follows. ◎: No trace on the rubbing surface

〇: Slight marks are left on the rubbing surface

△: White marks are left on the rubbing surface

X: No film on the rubbing surface

Next, the evaluation of the coating adhesion of the top coat will be described.

Paint adhesion was evaluated by a secondary adhesion test.

In the secondary adhesion test, the test plate was immersed in boiling water for 30 minutes, and then the following three items were evaluated: grid, elixir, and grid + Eriksen.

For the grid items, cut 100 lmm grids on the test board, apply adhesive tape (Nichiban cellophane tape) on the grids, and peel off the tape to determine the tape peelability according to the following criteria. It was evaluated on a scale of 10 out of 10.

For the Erichsen item, a part of the test plate surface was processed using an Erichsen tester so as to protrude 7 mm, an adhesive tape was attached, and the same evaluation as the above-mentioned grid items was performed.

For the items of the grid and the Eriksen, the grid is formed in advance and then processed using an Erichsen tester so that the grid-formed part protrudes by 7 mm. The same evaluation as the item of the eye was performed. The evaluation criteria for all three items are as follows.

10 points: no peeling

9 points: The coating film residual ratio is 90% or more

8 points: 80% or more

7 points: 70% or more

6 points: 60. /. that's all 14

5 points: 50 points. /. that's all

4 points: 40% or more

3 points: 30% or more

2 points: 20% or more

1 point: 10% or more

0 point: same 0 ~: L Less than 0% Industrial applicability

According to the metal surface treating agent, the metal surface treating method and the surface treated metal material according to the present invention, the metal surface treating agent used is an ethylene-unsaturated carboxylic acid containing 10 to 30% by mass of an unsaturated carboxylic acid. 30% or more of the carboxyl groups of the copolymer are neutralized with potassium ion, and the aqueous dispersion resin obtained by reacting the ionomer resin water-dispersed with the epoxy compound contains the conductive and corrosion-resistant coatings. In addition, it is possible to obtain an effect of excellent coating adhesion when a top coat is formed on the film.

Further, according to the metal surface treatment agent, the metal surface treatment method and the surface treated metal material according to the present invention, the aqueous dispersion resin is further compounded or compounded with another resin, or further mixed with silica fine particles. Has better corrosion resistance.

Claims

1 5 Claims

1. 30% or more of the carboxyl groups of an ethylene-unsaturated carboxylic acid copolymer containing 10 to 30% by mass of unsaturated carboxylic acid is neutralized with potassium ion to form a water-dispersed ionomer resin and epoxy resin. A metal surface treating agent comprising an aqueous dispersion resin obtained by reacting with a compound.

2. A metal surface treating agent comprising a composite water-dispersible resin obtained by radical polymerization of an unsaturated monomer in the presence of the aqueous dispersion resin according to claim 1.

3. At least one aqueous resin selected from the group consisting of an aqueous polyurethane resin, an aqueous polyester resin, and an aqueous acrylic resin is added to the aqueous dispersion resin according to claim 1 or the composite aqueous dispersion resin according to claim 2. A metal surface treatment agent characterized by being further compounded.

4. In a mixture of the aqueous dispersion resin according to claim 1 and at least one aqueous resin selected from an aqueous polyurethane resin, an aqueous polyester resin, and an aqueous acryl resin, an unsaturated monomer is used. A metal surface treatment agent comprising a composite aqueous dispersion resin mixture obtained by radical polymerization.

5. The metal surface treating agent according to any one of claims 1 to 4, further comprising silica fine particles.

6. A metal surface treatment method comprising applying the metal surface treatment agent according to any one of claims 1 to 5 to a metal surface to form a film.

7. The metal surface treatment method according to claim 6, wherein a top coat is further applied on the coating to form a coating. 1 6

8. A surface-treated metal material obtained by the metal surface treatment method according to claim 6 or 7.