JPS58213064A - Corrosion-resistant metal surface treating composition having excellent bending processability and scratching resistance - Google Patents

Abstract

PURPOSE:To provide the titled compsn. consisting of a specified aq. polymer emulsion and a water-soluble Cr compd. CONSTITUTION:100pts.wt. alpha,beta-monoethylenically unsaturated monomer or mixture thereof with a polyfunctional monomer having at least two radical-polymerizable ethylenically unsaturated groups per molecule is emulsion-polymerized in an aq. medium contg. 5-100pts.wt. (on a solid basis) emulsifier composed of a copolymer of polyacrylic acid and/or (meth) acrylic acid, (meth) acrylamide and a hydrophilic monomer of the formula [wherein A is H, methyl; R is a 2-4C (un)substituttd alkylene; X is a functional group contg. at least one atom selected from O, P and S] to obtain an emulsion (A) of hard polymer particles having a particle size of 0.1-3mu and a glass transition point of 15-110 deg.C. Component A and a water-soluble Cr compd. (B), in which 30-50wt% of the total amount of Cr is trivalent Cr, are blended in a weight ratio of solid of component A to metallic Cr of component B of 2:1-5:1.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a coating base treatment composition for metals, and more particularly, it uses a specific water-soluble polymer as an emulsifier, and
An aqueous polymer emulsion consisting of polymer particles with a specific particle size, a specific glass transition temperature, or a hard internal structure obtained by emulsion polymerization of a β-monoethylenically unsaturated monomer, and a specific percentage of the total chromium content. The present invention relates to a metal surface treatment composition that contains a water-soluble chromium compound, which is trivalent chromium, as a main component and has particularly excellent bending workability, scratch resistance, and corrosion resistance.

Various chemical conversion treatments have been applied to iron, galvanized steel sheets, aluminum, and other metal substrates to improve their corrosion resistance and paint film adhesion, but treatments based primarily on synthetic latex and water-soluble chromium compounds have been used. A metal surface treatment method using a so-called non-rinse chromate treatment agent, in which a liquid is simply applied to the metal surface, has recently become popular due to its ease of treatment operation and management, avoidance of wastewater pollution problems, and shortening of the treatment process. It is attracting particular attention. As a metal surface treatment method using a treatment liquid containing such an emulsion and a water-soluble chromium compound, for example, JP-A-50-57931;
Special Publication No. 49-31026, No. 49-40865, No. 5
A number of proposals were made, such as No. 0-1889, but the problem with these early treatment liquids was the presence of surfactants and emulsifiers in the production of emulsions. In other words, in order to maintain the stability of the emulsion itself, the use of nonionic or anionic surfactants is considered to be unavoidable, and on the other hand, the presence of this surfactant can affect the effectiveness of subsequent coating after the formation of the base film. It was also natural that this would have a significant adverse effect on the adhesion, corrosion resistance, moisture resistance, etc. of the coating film. Therefore, research continued with the aim of solving the chemical stability of emulsions without using surfactants during production, and at the same time obtaining a stable composition with chromium compounds. A technology for use as an emulsifier in the production of emulsions has now been provided. That is, in JP-A-51-74934, α,β-ethylenically unsaturated monomers are polymerized at a specific temperature in the presence of a water-soluble persulfate using a specific amount of a specific polyacrylic acid or its ammonium salt. A composition obtained by blending an emulsion of the polymer obtained with a hexavalent chromium compound was also published in Japanese Patent Publication No. 56
-39393 discloses an emulsion obtained by emulsion polymerization of α,β-monoethylenically unsaturated monomers using a specific amount of polyacrylic acid and/or acrylic acid copolymer as an emulsifier, a water-soluble chromium compound, and a water-soluble white carbon. Each method for surface treatment of metals using a treatment liquid containing as a main component is shown.

Emulsions obtained by using such water-soluble organic polymers as emulsifiers are chemically stable in themselves, and when combined with chromium compounds, provide stable processing solutions and form films with excellent corrosion resistance and paint adhesion. It is useful as a metal surface treatment agent. However, when considering the method of treating the base for painting metal materials, it is important to consider not only the adhesion between the treated surface and the paint, but also the adhesion of the paint film and scratch resistance when the gold layer is folded and processed in other ways after painting. It needs to be fully considered. In the first place, adhesion during folding and scratch resistance are mutually exclusive requirements, but the above-mentioned Japanese Patent Application Laid-Open No. 51-749
Invention No. 34 focuses only on processing adhesion and does not give any consideration to scratch resistance.
In No. 39393, the effect is based on the synergistic effect of the three components of an emulsion, a water-soluble chromium compound, and a water-soluble white carbon, and there is no mention of scratch resistance and bending resistance in a system consisting of an emulsion and a chromium compound. do not have. It has also been found that the effects of the three-component system on scratch resistance and folding resistance vary, and that good bundling is not always achieved. In particular, there are problems with folding resistance at low temperatures, and problems such as poor storage stability of crude oil are also recognized when the amount of trivalent chromium is large.

Therefore, the object of the present invention is to provide a metal surface treatment composition containing an emulsion and a chromium compound as main components, in which the emulsion itself is stable even without a surfactant, and the composition contains a chromium compound and stable inclusions. The treatment has excellent storage stability, especially as a stock solution before dilution, and when formed into a film, it has excellent corrosion resistance and water resistance, and is well-balanced in terms of scratch resistance and folding resistance at room temperature and low temperature. An object of the present invention is to provide a metal surface treatment composition capable of forming a film.

The present invention maintains the stability of the emulsion itself and chemical stability without containing a surfactant, and provides a treated film with excellent corrosion resistance, water resistance, and coating adhesion. No. 51-74934, JP-A-56-39
This invention is an extension of the No. 303 invention, and was made by focusing on stress relaxation on the treated surface in order to balance the conflicting requirements of foldability and scratch resistance. In recent years, as coated steel sheets for rate metals, original plates for the purpose of improving corrosion resistance after processing, that is, original plates that do not form cracks at all or are difficult to form on the surface during folding, have been commercially available. In this case, since stress relaxation due to cracks is essentially rejected, it is natural that the coating film adhesion deteriorates with the conventional uniform coating, which cannot be handled. However, if it is possible to intentionally disperse the adhesion points of particles in a non-uniform film, it is quite conceivable that it will be useful for stress relaxation. Naturally, metal surfaces are extremely uneven from a microscopic perspective. Therefore, if the resin particle size is made small enough so that the particles can fit into these depressions, and the particles themselves are made to be somewhat hard, the resistance to shear stress will be large and this will help alleviate stress in the vicinity of the particles. Become. As a result of various studies based on the above-mentioned theoretical considerations (although not bound by the theory in any way), the present inventors found that the particle size of the polymer particles of the emulsion is within a certain range, If the glass transition temperature is within a specific range, or if the polymer particles themselves are internally gelled and hard, the film will have excellent corrosion resistance, folding resistance, scratch resistance, etc. The present invention was completed after discovering that it is possible to obtain a coating-type non-rinse chromate treatment agent that provides the following properties.

In other words, according to the present invention, polyacrylic acid and
and X represents a functional group having at least one of an oxygen atom, a phosphorus atom, and a sulfur atom). Granules obtained by emulsion polymerization of an α,β-monoethylenically unsaturated monomer using 5 to 100 parts by weight of the following dairy products as solids per 100 parts by weight of the monomer. A monomer having a diameter within the range of 0.1-3μ and having two or more radically polymerizable ethylenically unsaturated groups in the molecule as part of the α,β-monoethylenically unsaturated monomer. Alternatively, the glass transition temperature can be adjusted to 15°C to 110°C by selecting the α,β-monoethylenically unsaturated monomer.
An emulsion of hard polymer particles obtained either within the range of The weight ratio of
A corrosion-resistant metal surface treatment composition with excellent folding workability and scratch resistance characterized by a ratio of 5:1 to 5:1 is provided.

The emulsion in the present invention uses a specific water-soluble polymer as an emulsifier in a specific ratio, and is selected from ordinary α,β-monoethylenically unsaturated monomers so that the glass transition temperature of the resulting polymer falls within a specific range, or Alternatively, at least one monomer having two or more radically polymerizable ethylenically unsaturated groups (hereinafter referred to as a polyfunctional monomer) is present in the monomer to be polymerized, Manufactured by emulsion polymerization means.

The water-soluble polymers include polyacrylic acid and/or acrylic acid and methacrylic acid, acrylamides (e.g. acrylamide and N-methylol-acrylamide), methacrylamides (e.g. methacrylamide and N-methylolmethacrylamide). , and a hydrophilic monomer represented by the above general formula (for example, as a monomer when X is a functional group having an oxygen atom,
2-hydroxylethyl acrylate, 3-hydroxybutyl acrylate, 2,2-pis(hydroxymethyl)ethyl acrylate, 2,3-dihydroxypropyl methacrylate, 3-hydroxybutyl methacrylate, etc.; X has a phosphorus atom Monomers when it is a functional group such as mono(2-hydroxyethyl methacrylate) acid phosphate and mono(3-chloro-2-hydroxypropyl methacrylate) acid phosphate; and monomers when x is a functional group having a sulfur atom It is a copolymer with at least one selected from the group consisting of sulfonyl ethyl methacrylate, etc.), and can be used alone or in a mixture of two or more thereof. The ratio of acrylic acid and other hydrophilic monomers in the above copolymer is such that the acrylic acid content in the total monomers is usually 50% by weight or more, preferably 60% by weight, from the viewpoint of stability of the emulsion system and adhesion to metal substrates. It is selected as appropriate so that the above is achieved.

Examples of α,β-monoethylenically unsaturated monomers to be emulsion polymerized include acrylic esters (methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, Decyl acrylate, isooctyl acrylate, 2-ethylbutyl acrylate, octyl acrylate,
methoxyethyl acrylate, ethoxyethyl acrylate, 3-ethoxypropyl acrylate, etc.), methacrylic acid esters (methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-methacrylate) hexyl, lauryl methacrylate, decyl octyl methacrylate, stearyl methacrylate, 2-methylhexyl methacrylate, dalicidyl methacrylate, 2-methacrylate
ethoxyethyl, cetyl methacrylate, pendyl methacrylate, 3-methoxybutyl methacrylate, etc.), acrylonitrile, methacrylonitrile, vinyl acetate, vinyl chloride, vinyl ketone, vinyltoluene and styrene. One or a mixture of two or more of these may be used. In addition to these, a small amount of acrylamides, methacrylamides, and hydrophilic monomers represented by the above general formula, which are constituent monomers of the water-soluble copolymer described above, may be added. In particular, by adding a monomer having an OH group, such as 2-hydroxyethyl methacrylate, the emulsion polymer can
Because it has a crosslinked structure with the base metal, the formed base film has significantly improved adhesion to the metal cable. Although not essential in the present invention, it has been found that it is preferable to include acrylonitrile in an amount of 5 to 10% in the total monomers, as this further improves the adhesion between the emulsion particles and the metal surface.

In the present invention, as described below, hard polymer particles emulsion 1:3
- one of the ways to obtain such hard particulate polymers is to make internal gelling polymers, in which case as part of the α,β-ethylenically unsaturated monomers,
A polyfunctional monomer having two or more radically polymerizable ethylenically unsaturated groups in the molecule is used. Examples of such polyfunctional monomers include polymerizable unsaturated monocarboxylic acid esters of polyhydric alcohols, polymerizable unsaturated alcohol esters of polybasic acids, and aromatic compounds substituted with two or more vinyl groups. Yes, the following are typical examples:

Ethylene glycol diacrylate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, 1,4- Butanediol diacrylate, neopentyl glycol diacrylate, 1,6-hexanediol diacrylate, 14
- Pentaerythritol diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, pentaerythritol dimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, glycerol dimethacrylate, glycerol diacrylate, glycerol allyloxy dimethacrylate, 1, 1,1-trishydroxymethylethane diacrylate, 1,1,1-
Trishydroxymethylethane triacrylate, 1,
1,1-trishydroxymethylethane dimethacrylate, 1,1,1-trishydroxymethylethane trimethacrylate, 1,1,1-trishydroxymethylpropane diacrylate, 1,1,1-trishydroxymethylpropane triacrylate , 1,1,1-trishydroxymethylpropane dimethacrylate, 1,1,
1-Trishydroxymethylpropane trimethacrylate, triallyl cyanurate, triallyl isocyanurate, triallyl trimellitate, diallyl terephthalate, diallyl phthalate and divinylbenzene.

The emulsion polymerization in the present invention is carried out in an aqueous medium in the presence of a water-soluble free radical catalyst free of alkali metal ions, such as ammonium persulfate and 2,2-azobis-(2-amidinopropane) hydrochloride, under conventional conditions and techniques. be given For example, in water (preferably deionized water) containing all or part of the emulsifier maintained at the polymerization temperature, optionally added polyfunctional unsaturated monomers and α,β-monoethylenically unsaturated monomers are added. Water-soluble catalyst without saturated monomers and alkali metal ions (
For example, ammonium persulfate) and, if necessary, water (preferably deionized water) containing the remainder of the emulsifier are simultaneously added dropwise from separate dropping funnels and, if necessary, aged at the same temperature. The polymerization is carried out under stirring, and the polymerization temperature is usually 50°C to 70°C, preferably 55°C to 65°C, to give good results in terms of scratch resistance. The polymerization time (dropping time + aging time) is usually 3 to 7 hours. The amount of the emulsifier to be used is selected within the range of 5 to 100 parts by weight in terms of solid content per 100 parts by weight of the α,β-monoethylenically unsaturated monomer to be subjected to emulsion polymerization. If the amount used is less than 5 parts by weight, the storage stability of the emulsion itself will be reduced, and even if it is used in excess of 100 parts by weight, the storage stability of the emulsion itself and the chemical stability against water-soluble chromium compounds will be particularly impaired. This does not result in a good result, and on the contrary, the problem of formation of an emulsion occurs.

However, in the present invention, it is essential that the emulsion particles obtained by such emulsion polymerization means have a particle size within the range of 0.1 to 3 .mu.m. As already mentioned, in the formation of a non-uniform film, it is necessary for the emulsion particles to be distributed coarsely so that they can fit into the hollows of the fine irregularities of the metal surface and be bonded to the metal surface for good adhesion. ,
According to research by the present inventors, the particle size of emulsion particles is 0.
．． It has also been confirmed that significant adhesion is obtained when the particle size is within the range of 1 to 3 microns, and a particularly preferred particle size is around 0.5 microns. (2) Generally, in emulsion polymerization, a heating means is used under high speed stirring to obtain fine emulsion particles, but it is also known that the particle size can be controlled by changing the operating conditions. Therefore, optimal conditions for keeping the particle size within the above range will be appropriately selected by those skilled in the art.

In the present invention, another important condition is that the emulsion particles are hard particles with relatively high resistance to shear stress, so the emulsion particles defined by the glass transition temperature (Tg) or internal gelation of the polymer are Because of the specific particle size, the particles fit into minute hollows on the metal surface, but if the particles are relatively hard, it is thought to be useful for relaxing stress near the particles. The inventors have in fact found that the Tg of the polymer
or within the range of 15°C to 110°C, more preferably 40C to 1
It has been found that if the temperature is within the range of 10°C, a significant improvement can be obtained in the folding processability and scratch resistance of the film.

If the Tg of the polymer is less than 15° C., a film with sufficient properties, especially folding resistance and scratch resistance, cannot be obtained. On the other hand, polymers with a Tg of 110 DEG C. or higher cannot be obtained from the commonly used α,=18-β-ethylenically unsaturated monomers.

The Tg of a polymer can be predicted to some extent by calculation based on the type and amount of monomers to be polymerized, and those skilled in the art can easily design the glass transition temperature within the above range. The polymer particles also include polyfunctional unsaturated monomers as described above as part of the monomer components to be polymerized,
Hardening can also be achieved by causing internal gelation.

In this case, the amount of the polyfunctional monomer is not particularly limited as long as hardening is achieved by internal gelation of the polymer particles;
．． It is sufficient to select it within the range from 0.01 to 20% by weight, particularly preferably from 0.1 to 10% by weight.

In the present invention, a specific amount of a water-soluble chromium compound is added to the emulsion obtained as described above to prepare a composition for metal surface treatment.

In the present invention, it is important that the content ratio of trivalent chromium in the water-soluble chromium compound is set in the range of 30 to 50% by weight, preferably 35 to 45% by weight based on the total amount of chromium. Therefore, within the range that satisfies these conditions, C
A chromium compound such as rO3 may be partially reduced in advance with formalin, hydrogen peroxide, or the like. The content ratio of trivalent chromium is 3
If it is less than 0% by weight, the resistance to folding and the like will deteriorate. Moreover, if it exceeds 50% by weight, the stability of the stock solution becomes poor when it is blended as a processing agent.

The metal treatment composition of the present invention is prepared by mixing the above emulsion and a water-soluble chromium compound in water (preferably deionized water) all at once. It is possible to store a concentrated stock composition using a relatively small amount of water and dilute it appropriately with water before use, or to directly prepare a treatment solution using a relatively large amount of water. The mixing ratio of the emulsion and the water-soluble chromium compound must be within the range of 2:1 to 5:1 in terms of the solid content of the emulsion and the polymerization ratio of metallic chromium, and the most preferable ratio is 3:1.

If the proportion of metallic chromium is smaller than the above range, the corrosion resistance of the coated plate will decrease and the adhesion between the base film and the metal surface will not be sufficient, and if it is larger than the above range, problems will arise in the adhesion of the coated plate.

If desired, fine particle silica (7 to 60 mμ) can be added to the metal surface treatment composition of the present invention in an amount comparable to that of chromium to further improve the scratch resistance. Further, sources of various metal ions (excluding alkali metal ions) and inorganic ions may be added within a range that does not impair the stability. This ion addition makes it possible to form a base film that is more uniform and has better adhesion to the metal surface. Such additive ions include, for example, Zn2
+, Ca2+, Ni2+, Te+, PO43-, F-,
Examples include BF4-, SiF62-, and the like.

The metal surface treatment composition according to the present invention is applied to the surface of various metals (e.g. iron, galvanized steel, aluminum, etc.) according to a conventional method (e.g. roll coating method, mist spray method, dip method), and then dried as appropriate. By doing so, a desired base film can be formed. The forming part of such upper film is usually 5mg/for metal chromium film.
m2-1g-m2, preferably 5mg/m2-100m
It is sufficient to select within the range of g21-m2, and if it deviates from this range,
The processing performance of the resulting coated board tends to deteriorate. Among the above coating methods, the roll coating method is suitable for coil coating lines for galvanized steel, iron, and aluminum, and provides a thin and uniform base film without color unevenness.

The above drying conditions may be such as to evaporate the moisture in the base film, and the maximum board temperature is 120°C or less.
Preferably a temperature of 80°C to 110°C for 1 to 60 seconds is suitable for the present invention. Outside this range, clumping may occur, which is undesirable for improving the adhesion of the coated film, especially the scratch resistance. The formed film does not contain any surfactants or other substances mixed into the emulsion in our processing solution, has extremely good corrosion resistance and moisture resistance after painting, and also significantly improves paint adhesion such as workability and scratch resistance. .

In this way, the treatment composition of the present invention does not require maintenance of the treatment solution when used for gold-yang surface treatment, so it is only necessary to periodically fill the treatment solution with the same composition, and it can be used continuously. Uniform coating can be easily carried out, and a desired base film can be formed by drying. Further, there is no need for washing with water after application of the treatment liquid and post-treatment steps, making it possible to shorten the process, and also eliminating the need for equipment for treating contaminated wastewater. The formed film exhibits good properties as described above, and is particularly excellent in process resistance and scratch resistance, and is extremely useful for surface treatment of metals. It is also a feature of the composition of the present invention that it exhibits a more outstanding effect than conventional compositions, particularly in terms of storage stability of the treatment stock solution and processability at low temperatures.

The present invention will be explained below with reference to Examples, Reference Examples, and Comparative Examples. In the example sentences, "parts" and "%" mean "parts by weight" and "% by weight," respectively.

Emulsion Synthesis Reference Example 1 (High Tg emulsion EM NO. 1) In a flask equipped with a stirrer, reflux condenser, thermometer and two dropping funnels, 150 parts of deionized water and acrylic acid and 2-hydroxyethyl methacrylate were added. and 120 parts of a water-soluble copolymer (25% aqueous solution, molecular weight MW 66,000) obtained by copolymerizing at a weight ratio of 8:2 and stirred.
Raise the temperature to 0-85°C. Next, a monomer mixture consisting of 50 parts of methyl methacrylate, 30 parts of styrene, 10 parts of 2-hydroxyethyl methacrylate, and 10 parts of n-butyl methacrylate was added to this from one funnel, and 2 parts of ammonium persulfate and deionized water were added. 50 parts of catalyst solution are simultaneously added dropwise from the other funnel over a period of 3 hours.

After dropping, the mixture is further aged at 80 to 85° C. for about 2 hours to complete the polymerization reaction. The resulting aqueous polymer has a solid content of 30
．． It was a uniform and stable emulsion with a concentration of 1%, pH 1.6, particle size 0.2μ, and Tg 89°C.

Reference Example 2 (Internal Gelled Emulsion FM No. 2) The monomer mixture was 50 parts of methyl methacrylate and 27 parts of styrene.
Emulsion polymerization was carried out in the same manner as in Reference Example 1, except that the mixture consisted of 10 parts of 2-hydroxyethyl methacrylate, 10 parts of n-butyl methacrylate, and 3 parts of ethylene glycol dimethacrylate.

The obtained aqueous polymer was a uniform and stable emulsion with a solid content of 30.0%, pH 1, and particle size of 0.55 μm, and the emulsion particles were not dissolved in xylene.

Reference Example 3 (Emulsion EM No. 3 containing acrylonitrile and high Tg) Monomer mixture contains 50 parts of methyl methacrylate and 2 parts of styrene.
Emulsion polymerization was carried out in the same manner as in Reference Example 1, except that the mixture was composed of 5 parts of 2-hydroxyethyl methacrylate, 10 parts of 2-hydroxyethyl methacrylate, 10 parts of n-butyl methacrylate, and 5 parts of acrylonitrile. The resulting aqueous polymer had a solid content of 30.3% and a pH of 1.
6. It was a uniformly stable emulsion with a particle size of 0.2μ and a Tg point of 89°C.

Reference Example 4 (Comparative emulsion EM No. 4 with low Tg)
4) Monomer mixture contains 75 parts of ethyl acrylate and 15 parts of styrene.
emulsion polymerization was carried out in the same manner as in Reference Example 1, except that 10 parts of 2-hydroxyethyl methacrylate were used. The obtained aqueous polymer was a uniformly stable emulsion with a solid content of 30.2%, a pH of 1.6, a particle size of 0.2μ, and a Tg of -2°C.

25-Example 1 Preparation of treatment liquid Emulsion EM N0.1 obtained in Reference Example 1 (solid content 30.1%, particle size 0.2μ, Tg 89°C 29.6 parts and a 17% aqueous solution of chromic anhydride) 33.6 parts of chromium aqueous solution obtained by adding 37% formalin and reducing 40% of hexavalent chromium to trivalent chromium (metallic chromium content = 33.6 x 0
．． A processing composition stock solution obtained by stirring and mixing 17× (Cr/CrO3 coefficient 0.52)) and 36.8 parts of deionized water at room temperature was diluted 5 times with deionized water to prepare a treatment solution. . The weight ratio of emulsion solid content to metallic chromium is 3:
It was 1.

Metal surface treatment and painting Ordinary zinc-plated steel sheets (zero spangle sheets, with skin pass) that tend to crack when folded are treated with a commercially available alkaline degreaser (manufactured by Nippon Paint Co., Ltd., trade name Ridrin 15).
5) After degreasing and washing, washing with water and drying the surface, apply the above treatment solution to the surface using a #3 bar in an amount of 30 mg/m2 of metallic chromium.
The coated film was coated with a 26-cm coat and then dried with hot air at 70°C to obtain a uniform base film.

Next, as an undercoat on the surface-treated spangle board as described above, Nippon Paint Co., Ltd.'s product name "Superlac DIF" was applied as an undercoat.
Apply "P-75 Primer" to a dry film thickness of 3μ, bake to reach a board temperature of 204℃ in 50 seconds, and then apply topcoat paint manufactured by Nippon Paint Co., Ltd. under the trade name "Superlac DIF F-50 Red Rust Color". " was applied to a dry film thickness of 11 μm and baked to reach a plate temperature of 204° C. in 50 seconds.

Table 1 shows the test results for the treatment agent stock solution composition and the obtained coated board.

Example 2 Emulsion EM No. obtained in Reference Example 2 2 to 29.
7 parts of the chromium aqueous solution described in Example 1, and 36.7 parts of deionized water to prepare a treatment composition stock solution in the same manner as in Example 1, and add 3.75 parts of this with deionized water. A treatment solution was prepared by diluting it twice. The weight ratio of emulsion solids to metallic chromium was 3:1.

The above treatment solution was applied to a zero spangle plate in the same manner as in Example 1 so that the coating amount of metallic chromium was 40 mg/m 2 , and then, in the same manner as in Example 1, it was coated with an undercoat and a topcoat. The test results are shown in Table 1.

Example 3 Emulsion EM No. obtained in Reference Example 3. 329.
A treatment composition stock solution was prepared in the same manner as in Example 1 from 4 parts, 33.6 parts of the aqueous chromium solution described in Example 1, and 37.0 parts of deionized water, and diluted 5 times with deionized water to make the treatment solution. It was adjusted. Then, in the same manner as in Example 1, it was applied to a zero spangle board to form a base film, which was then painted with an undercoat and a topcoat. However, the amount of treatment liquid applied during the formation of the base film was set to 30 mg/m2 of metallic chromium. The test results were as shown in Table 1.

Comparative Example 1 Emulsion obtained in Reference Example 4 (low Tg) 2
The same method as in Example 1 was carried out except that 9.5 parts were used, and the test results are shown in Table 1.

In addition, in Table 1 below, the stability of the stock solution was evaluated by visually observing the condition of the stock solution after keeping the processing composition stock solution in a sealed polyethylene container at 20°C for one month, and if there were no abnormalities. If gelation occurs, mark it as ○, or mark it as × if gelation occurs.
It was shown in

OT folding processability is 10 points (no abnormality) to 1 point (full peeling) after peeling off the folded surface with adhesive tape.
Evaluation was made using a 0 point system.

Table 1 (test with zero spangle plate) = 29 - Examples 4 to 9 and Comparative Examples 2 to 6 The emulsions obtained in Reference Examples 1 to 4 were used in Examples 4, 5, 6 and Comparative Example 2. Each used, and Reference Example 1
The products obtained in Example 7 to 9 and Comparative Examples 3 to 6 were used in the same manner as in Example 1 according to the formulation shown in Table 2 below (however, in the case of adding silica, 10% of Aerosil 300 was used).
Each treatment solution was prepared by adding deionized water to the dilution ratio shown in Table 2.

A hot-dip galvanized steel plate (regular spangle, no skin pass), which is difficult to crack when folded, was used as the metal material, and a base film was made with the above treatment solution in the same manner as in Example 1.
An undercoat paint ``Superlac-30-DIE P-75 Primer'' and a topcoat paint ``Superlac DIF F50 Rust Color'' were applied and subjected to an OT bending test (20°C). Separately, after forming the above-mentioned base film,
Apply IF F-15 beige color to 1μ of dry film,
1C baked so that the plate temperature reached 210℃ in 50 seconds
/1B (one coat, one bake) was subjected to the following coin scratch test.

Coin scratch resistance: Scratch the painted surface with a 10 yen hard circle without notches on the circumference,
Evaluation is on a 5-point scale from 1 point (excellent) to 1 point (poor).

The composition of the stock solution, treatment solution, treatment, and performance are shown in Table 2 below. Regarding the stock solution stability in the table, the symbol △ means that thickening was observed.

Table 2 (Test on regular spangled board) The composition of the present invention not only provides a film with excellent corrosion resistance and water resistance, but also provides a treated film with excellent storage stability, scratch resistance, and folding workability. Giving can be easily understood.

12th application agent 1゛ Buried'' - Italy Takeshi ME' 33- Procedure Sodeichi i'i - (Method) % formula % (111゛11 Osaka City Nitoyo 1 Me Yodokita 2-chome-ro 1 Mr. 2
``'''') 11 Hein ha' type company representative moss Masao Suzumoto 4, amendment to agent procedure July 15, 1981 Director-General of the Patent Office Fishi 2 Fu c 4 Shin Y 7 (71 Shi enter 2, Fu Lll → 7 Relationship with the Case of Compiled Oxide Compound 3 for Excellent Corrosion Resistance Metal Surface Treatment Patent Applicant Address FUi%FUJIKIN”; <'4! 2-1-2 Name
Nippon Paint Co., Ltd. Representative Masao Suzuki 4 Agent address 6th floor, Building River Center, 3-57 Kyobashi, Higashi-ku, Osaka, 540 Name Patent attorney (6871) Takeo Ito Date of 5th amendment order 6 Inventions increased by amendment -1, on page 2, line 9 of the specification, the phrase ``of polymer particles'' should be corrected to ``consisting of polymer particles.''

2. Add "50°C...1" to lines 17 to 19 on page 16. ”, li
'50° (', ~9 (PiC)) is used. Corrected to J.

3, page 17, line 19 It says "Particle size is around 0.5μ", “The particle size range is corrected to 0.3μ to 2μJ.

4. From the bottom of the 30th line to the 7th line [It says Aerosil 3001.

“Aerosil 300 (product name manufactured by Roki Aerosil Co., Ltd.)
I am corrected.

that's all

Claims (4)

[Claims] (1) Polyacrylic acid and/or acrylic acid and methacrylic acid, acrylamides, methacrylamides and the general formula (where A is a hydrogen atom or a methyl group, R is a C2-C4 substituted or unsubstituted alkylene group, and represents a functional group having at least one of an oxygen atom, a phosphorus atom, and a sulfur atom). A saturated monomer, provided that the above-mentioned emulsifier is used at a solid content of 5 to 100 parts by weight per 100 parts by weight of the monomer, and obtained by emulsion polymerization, with a particle size in the range of 0.1 to 3μ. internal gelation using a monomer having two or more radically polymerizable ethylenically unsaturated groups in the molecule as part of the α,β-monoethylenically unsaturated monomer. Or, by selecting the α,β-monoethylenically unsaturated monomer, the glass transition temperature can be adjusted to 15°C to 11°C.
An emulsion of hard polymer particles obtained either within the range of 0°C and 30 to 50% of the total chromium content.
The main component is a water-soluble chromium compound whose weight% is trivalent chromium, and the weight ratio of emulsion solid content to metallic chromium is 2.
:1 to 5:1.A corrosion-resistant metal surface treatment composition having excellent folding workability and scratch resistance. (2) The composition according to claim 1, wherein the content of trivalent chromium in the water-soluble chromium compound is 35 to 45% by weight based on the total amount of chromium. (3) The glass transition temperature of the emulsion polymer is 40℃
The composition according to any one of claims 1 to 2, which has a temperature of ~110°C. (4) The composition according to any one of claims 1 to 3, wherein the weight ratio of emulsion solid content to metal chromium is 3:1.