JPH0647743B2 - Metal surface treatment agent - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a metal surface treatment agent, and in particular, phosphoric acid for cold rolled steel sheet, high strength steel sheet, carbon steel, zinc, aluminum, zinc plated steel, tin plated steel or lead plated steel. The present invention relates to a salt (for example, zinc phosphate, iron phosphate, manganese phosphate, calcium phosphate, etc.) or a metal surface treatment agent for post-treatment after chromic acid treatment.

Conventionally, it has been known to perform surface treatment using a water-soluble resin for the purpose of preventing corrosion of steel plates, zinc iron plates, tinplate, etc. (Japanese Patent Publication No. 37-11508, Yawata Steel Co., Ltd.). However, even in this case, there is a problem with the adhesiveness with the paint, and in a harsh environment, the corrosion preventive property is insufficient and it is still not sufficient for practical use. It is also known to use a water-soluble resin as a maintenance paint on steel, stainless steel, aluminum, etc. (Surface, Vol. 20, No. 12, p. 730 (19).
82)). However, even in this case, heat resistance and durability are insufficient, and it is considered that the use is limited. In the case of coating automobiles, it is also known that a water-soluble cationic epoxy resin is subjected to cationic electrodeposition as a surface treatment for the purpose of rust prevention, but in this case also, the adhesion of the top coating is insufficient. It is also known to use tannin and melamine formaldehyde resin for surface treatment of metal instead of chromic acid treatment (USP 4,174,980, Oxy Metal In
d.Corp.). However, in this case, it is said that there is a problem in the homogeneity of the film formed by the surface treatment agent.

The present inventors have used a material containing a hydroxystyrene-based polymer as a main component as a metal surface treatment agent, and if the metal is surface-treated with it, the corrosion resistance and wear resistance of the metal are improved, and the top coating composition is also used. The present invention has been found to improve the adhesion or compatibility with and further improve the physical properties such as water resistance, heat resistance, aging resistance, flexibility, and the homogeneity of the surface after surface treatment. completed. That is, the gist of the present invention resides in the general formula (I) [In the formula, R is hydrogen, a methyl group or an ethyl group; Z is halogen, -SO ₃ M (M is hydrogen, an alkali metal or an alkaline earth metal), (R ₁ and R ₂ are alkyl groups having 1 to 8 carbon atoms), (R ₁ and R ₂ are alkyl groups having 1 to 8 carbon atoms, R ₃ is alkyl group or benzyl group having 1 to 8 carbon atoms, X is halogen), —CH ₂ —SO ₃ M (M is hydrogen, alkali metal) Or alkaline earth metal) or (R ₁ and R ₂ are hydrogen or an alkyl group having 1 to 8 carbon atoms,
t is 1, 2 or 3, a and b are 0 or 1, and a is 0
And b is also 0)], a unit represented by the general formula (II) [In the formula, R is the same as above; Y is an aralkyl group selected from an alkyl group having 1 to 8 carbon atoms, a benzyl group, a methylbenzyl group, an α-methylbenzyl group, and a phenylethyl group; Of an acyl group, an aryl group or an aromatic sulfonyl group of
I) [Wherein R, Z and Y are the same as above] containing at least one hydroxystyrene unit as an essential constitutional unit, and the rest of the formula (IV) [Wherein R is the same as above] and / or styrene, α-methylstyrene, acrylic acid and its ester, methacrylic acid and its ester, maleic acid and its ester, and maleic anhydride. Consists mainly of at least one comonomer unit selected from acids, and contains the above essential structural units in a proportion such that the introduction ratio of Z and / or Y is 0.1 or more as an average number per hydroxystyrene-based unit. However, Z is When the formula (I) does not mean that the hydroxystyrenic unit, which is an essential constitutional unit, consists of the general formula (I)
To (IV), a metal surface treatment containing a hydroxystyrene polymer having a molar ratio of comonomer units to the total of hydroxystyrene units of less than 10 and a weight average molecular weight of 500 to 100,000 as a main component Exist in the drug.

The metal surface-treating agent containing the above hydroxystyrene-based polymer as a main component according to the present invention is excellent in the effect of improving the corrosion resistance and wear resistance of the metal, the adhesion between the metal and the top coating,
Excellent compatibility, flexibility, water resistance, etc.
Furthermore, the surface uniformity after the surface treatment is improved.

The above-mentioned hydroxystyrene-based polymer has a substituent represented by Z in the general formulas (I) and (III) of the hydroxystyrene-based unit, or has the general formula (II) and (III ) Has a substituent as represented by Y, or this Z
A homopolymer of hydroxystyrene, isopropenylphenol (hydroxy-α-methylstyrene) or hydroxy-α-ethylstyrene, a copolymer thereof, or a hydroxystyrene-based homopolymer thereof having both the substituents Y and Y. It may be a copolymer of a monomer and another vinyl monomer. However, Z is In this case, the hydroxystyrene-based unit of the essential constitutional unit does not consist only of the general formula (I), and Y is always present in the essential constitutional unit in addition to Z. The hydroxystyrene-based unit such as hydroxystyrene or isopropenylphenol as a polymerized unit may be an ortho isomer, a meta isomer, a para isomer or a mixture of these isomers, but a para isomer or a meta isomer is preferable. In addition, examples of other vinyl monomers in the case of being a copolymer include styrene, α-methylstyrene, acrylic acid ester, methacrylic acid ester, maleic acid and its ester, maleic anhydride and the like. Further, in this case, the ratio of the hydroxystyrene unit such as hydroxystyrene unit or isopropenylphenol unit to the other vinyl monomer unit is appropriately 1/10 to 20/1 in terms of molar ratio. Furthermore, chlorine, bromine or iodine is suitable as the halogen of the nuclear substituent of the hydroxystyrene unit. Also, the nuclear substituent of the hydroxystyrene unit Or The alkyl group represented by R _{1 to} R ₃ is preferably an alkyl group having 1 to 8 carbon atoms, Chlorine, bromine or iodine is suitable as the halogen of X in the above. Further, as the alkali metal or alkaline earth metal of M in the nuclear substituents —SO ₃ M or —CH ₂ —SO ₃ M of the hydroxystyrene unit, lithium, sodium, potassium, magnesium, calcium, strontium, barium, etc. Appropriate. Also, the nuclear substituent of the hydroxystyrene unit As the alkyl group represented by R ₁ and R ₂ in ( ₁₎ , an alkyl group having 1 to 8 carbon atoms is suitable. In addition, examples of the substituent and aromatic sulfonyl group in the phenolic hydroxyl group of the hydroxystyrene-based unit include a benzenesulfonyl group and a naphthalenesulfonyl group. The substituent and acyl group in the phenolic hydroxyl group preferably have 1 to 8 carbon atoms, and examples thereof include acetyl group, propionyl group, butyryl group, valeryl group, benzoyl group and toluoyl group. . The substituent and alkyl group in the phenolic hydroxyl group are preferably those having 1 to 8 carbon atoms, the aralkyl group is benzyl group, methylbenzyl group, α-methylbenzyl group or phenylethyl group, and the aryl group is A phenyl group or a naphthyl group is preferred. Also, the general formula
The hydroxystyrene-based polymer represented by (I) can be used as a metal surface treating agent as long as the hydroxystyrene-based polymer has a degree of polymerization of 3 or more, but generally has a weight average molecular weight of 500 to 10 10,000, preferably 100
The range of about 0 to 20,000 is suitable.

The hydroxystyrene-based polymer used as the metal surface treating agent in the present invention may be produced by any method, and its history is not limited. An example of the manufacturing method is as follows. The hydroxystyrene-based polymer in which Z in formula (I) or (III) is halogen can be prepared by halogenating a hydroxystyrene-based polymer with halogen as disclosed in, for example, Japanese Patent Publication No. 56-39762. Easily obtained. A hydroxystyrene-based polymer in which Z in the formula (I) or (III) is —SO ₃ M is
For example, as disclosed in JP-B-55-24444, a hydroxystyrene-based polymer is easily sulfonated with sulfuric acid or sulfuric acid anhydride and, if necessary, further reacted with an alkali metal or alkaline earth metal compound to facilitate the reaction. can get.

Z in formula (I) or (III) is Alternatively, The hydroxystyrene-based polymer is, for example,
Dialkylaminomethylation of hydroxystyrene polymers by Mannich reaction with formaldehyde and dialkylamines, as disclosed in US Pat. Is obtained), and the dialkylaminomethyl group introduced thereafter is quaternized by the Menschutkin reaction with an alkyl halide (where Z is Is obtained). formula
The hydroxystyrene-based polymer in which Z in (I) or (III) is —CH ₂ —SO ₃ M is described in, for example, JP-A-49-665.
As disclosed in No. 81, it is easily obtained by sulfomethylating a hydroxystyrene polymer with formaldehyde and sulfite. Formula (I) or (II
Z in I) The hydroxystyrene-based polymer which is represented by
As disclosed in 3-47489, the hydroxystyrene-based polymer is first halogenated or halomethylated, with which a trivalent phosphorus compound is reacted (Arbuzov reaction), and then by thermal rearrangement thereof to give Z. But And a hydroxystyrene-based polymer is reacted with phosphoric acid or a phosphoric acid ester group derivative after methylolation of the hydroxystyrene-based polymer, as disclosed in JP-A-53-71190. Yotsutte Z A hydroxystyrene-based polymer is obtained. The hydroxystyrene-based polymer in which Y in formula (II) or (III) is an alkyl group can also be obtained by vinyl polymerization of alkoxystyrene, and the hydroxyl group of the hydroxystyrene-based polymer can be converted into diazoalkyl, dialkylsulfate or It can also be easily obtained by etherification with an alkyl halide or the like. Y in formula (II) or (III)
The hydroxystyrene-based polymer in which is an aralkyl group or aryl group can be easily obtained by etherifying the hydroxyl group of the hydroxystyrene-based polymer with, for example, a benzyl halide, a naphthyl halide or the like. A hydroxystyrene polymer in which Y in the formula (II) or (III) is an aromatic sulfonyl group is obtained by converting a hydroxyl group of the hydroxystyrene polymer into a sulfonic acid ester with a benzenesulfonic acid halide or a naphthalenesulfonic acid halide. It's easy to get. The hydroxystyrene-based polymer in which Y is an acyl group in the formula (II) or (III) is a hydroxystyrene-based polymer whose hydroxyl group is acetic anhydride, n-butyric anhydride, valeric anhydride, benzoic anhydride, toluic anhydride, etc. It can be easily obtained by acylation with the acid anhydride or the chloride thereof. The introduction order of each substituent represented by Z and Y in the essential constitutional units of the formulas (I) to (III) may be arbitrary. Further, the introduction ratio of Z and / or Y is
An average number of 0.1 or more per one hydroxystyrene unit is suitable.

The hydroxystyrene-based polymer used in the metal surface treating agent of the present invention may be a kind of hydroxystyrene-based polymer in which the substituents represented by Z and Y are constant and, if necessary, Z It is also possible to mix and use two or more kinds of hydroxystyrene-based polymers in which one or both of the substituents represented by and Y are different substituents. Further, it is desirable that the hydroxystyrene-based polymer can be an aqueous solution because of its ease of use as a metal surface treating agent.

The above-mentioned hydroxystyrene-based polymer can be used in various modes when used as a metal surface treating agent. In general,
In the conventional metal surface treatment, after washing the surface-treated metal, it is usual to perform a percalizing treatment with a phosphate aqueous solution and, if necessary, a chromate aqueous solution. By the way, as one embodiment example of using a hydroxystyrene-based polymer as a metal surface treatment agent, it is possible to use an aqueous solution of a hydroxystyrene-based polymer together with an aqueous solution of a phosphate in the above-mentioned park aging treatment.
This makes it possible to reduce the amount of phosphate required for the parkarizing treatment and further improve the performance of the film formed by the synergistic effect of the chelating action of the phosphate and the polymer. As another example of the embodiment, after the above-mentioned parkerizing treatment, treatment with an aqueous solution of a hydroxystyrene-based polymer instead of the treatment with an aqueous solution of a chromate salt can be cited. In that case, the use of a chromate salt is unnecessary. Pollution due to chromium can be prevented. As yet another embodiment, in the treatment with the aqueous solution of chromate, it is possible to use an aqueous solution of a hydroxystyrene polymer together with the aqueous solution of chromate, which can reduce the amount of chromate required, It is possible to further improve the performance of the film formed by the synergistic effect of the chelating action of the chromate and the polymer.

The present invention will be further described with reference to the following examples, but the present invention is not limited to the following examples. Further, in the following examples, "%" means "% by weight" unless otherwise specified.

Example 1. After cold-rolled steel sheet is pre-treated with 0.3% caustic soda solution, rinsed with water and parkerized with 0.2% zinc phosphate aqueous solution at 65 ° C., then 0.3 pieces per phenol core polyparahydroxystyrene having a sulfomethyl group _{(-CH 2 -SO 3 H) (} ▲ ▼ = 6,70
0, ▲ ▼ / ▲ ▼ = 2.14) 5% alkaline aqueous solution (polymer concentration: about 10%), after post-treatment at 60 ℃, rinse completely and dry at 150 ℃ for 10 minutes. After curing, a thermosetting acrylic coating was applied.
Even if the obtained plate was subjected to the salt spray test of ASTM-B117-61 method for 672 hours, the plate showed good performance with no corrosion observed.

Examples 2 to 12 Evaluations as metal surface treating agents were carried out in the same manner as in Example 1 except that only the hydroxystyrene polymer had the structure and average molecular weight shown in Table 1.

Comparative Example 1. When the hydroxystyrene polymer was not used, the plate was corroded when the salt spray test was conducted for 120 hours.

Example 13 An alternating copolymer of parahydroxystyrene and maleic anhydride (50 mol% of parahydroxystyrene unit, 50 mol% of maleic anhydride unit), wherein 0.3 of parahydroxystyrene units were present per phenol nucleus. A polymer having bromine and having maleic anhydride units converted to maleic acid monoamide ammonium salt by ammonia (▲ ▼ = 4,900, ▲ ▼ / ▲ ▼ =
1.97) as a hydroxystyrene polymer,
An aqueous solution of the polymer 0.2%, sulfuric acid 0.1%, nitric acid 1%, sodium fluoride 0.15%, and chromic anhydride 0.2% was prepared.

After pretreating each of the two zinc plated steel sheets with an aqueous solution of 0.3% caustic soda, rinsing with water and performing a percalizing treatment with an aqueous solution of 0.2% zinc phosphate at 65 ° C. Post-treatment was carried out at 40 ° C. using the above-prepared aqueous solution, followed by thorough rinsing with water and drying at 80 ° C. for 20 minutes. One of the zinc plated steel sheets thus treated showed a rust resistance in which no white rust was observed even after a salt spray test for 72 hours.
A thermosetting acrylic coating was applied to the other zinc plated steel sheet thus treated, and then a salt spray test was carried out. Even if the test was carried out for 672 hours, good corrosion performance was not observed. Indicated.

Claims (1)

[Claims] 1. A general formula (I) [In the formula, R is hydrogen, a methyl group or an ethyl group; Z is halogen, -SO ₃ M (M is hydrogen, an alkali metal or an alkaline earth metal), (R ₁ and R ₂ are alkyl groups having 1 to 8 carbon atoms), (R ₁ and R ₂ are alkyl groups having 1 to 8 carbon atoms, R ₃ is alkyl group or benzyl group having 1 to 8 carbon atoms, X is halogen), —CH ₂ —SO ₃ M (M is hydrogen, alkali metal) Or alkaline earth metal) or (R ₁ and R ₂ are hydrogen or an alkyl group having 1 to 8 carbon atoms, t
Is 1, 2 or 3, a and b are 0 or 1, but b is 0 when a is 0)], a unit represented by the general formula (II) [In the formula, R is the same as above; Y is an aralkyl group selected from an alkyl group having 1 to 8 carbon atoms, a benzyl group, a methylbenzyl group, an α-methylbenzyl group, and a phenylethyl group; Of an acyl group, an aryl group or an aromatic sulfonyl group of
I) [Wherein R, Z and Y are the same as above] containing at least one hydroxystyrene unit as an essential constitutional unit, and the rest of the formula (IV) [Wherein R is the same as above] and / or styrene, α-methylstyrene, acrylic acid and its ester, methacrylic acid and its ester, maleic acid and its ester, and maleic anhydride. Consists mainly of at least one comonomer unit selected from acids, and contains the above essential structural units in a proportion such that the introduction ratio of Z and / or Y is 0.1 or more as an average number per hydroxystyrene-based unit. However, Z is When the formula (I) does not mean that the hydroxystyrenic unit, which is an essential constitutional unit, consists of the general formula (I)
To (IV), a metal surface treatment containing a hydroxystyrene polymer having a molar ratio of comonomer units to the total of hydroxystyrene units of less than 10 and a weight average molecular weight of 500 to 100,000 as a main component Agent.