JP2913843B2 - Metal rust preventive composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal rust preventive composition, and more particularly to a metal composition having good long-term storage stability at room temperature and existing in the atmosphere after being applied to a metal surface. It relates to a metal rust-preventing composition that forms an effective film by moisture or slight heating and exhibits good rust-prevention properties, especially zinc plating, nickel-zinc plating, iron-zinc plating, tin-zinc plating, etc. A rust-preventing composition suitable for zinc and zinc alloy plating and for metals that have undergone chromate treatment on such plating surfaces, and can be widely used in various industrial fields that use metals such as the machinery industry, electrical equipment industry, and automobile industry. is there.

[0002]

2. Description of the Related Art Conventionally, a large number of treating agents and paints have been used to protect metal surfaces from various corrosive environments.
Among them, paints that can be formed or cured at room temperature or slightly heated are widely used in terms of heat energy because they save resources and simplify the process. For example, a two-component paint such as polyurethane or epoxy, an air-dry paint such as alkyd or polybutadiene, and a moisture-curable paint such as silicone or various modified silicones may be used.

[0003]

However, paints which can be formed or cured by ordinary temperature or slight heating have the following problems.

[0004] That is, the two-part curable paint forms a dense coating film and has excellent rust-preventive properties, but is difficult to measure and mix when compounding a curing agent and has a short working time. The air-drying paint forms a coating film having excellent water resistance, but the residual unsaturated bond may lower the antioxidant property and weather resistance of the coating film. Silicone moisture-curable coatings having excellent weather resistance and heat resistance have problems in storage stability and rust prevention of coating films.

The present inventors have previously described Japanese Patent Application Laid-Open No. 59-96279.
Has proposed a metal rust preventive composition that can be cured at room temperature and exhibits excellent rust prevention with a much thinner film thickness than ordinary coatings, but is used for the purpose of improving rust prevention. Even if a rust preventive, a rust preventive pigment, etc. are added, the reaction with the active groups on the particle surface such as the pigment and the adsorbed moisture on the particle surface is less, and there is a demand for a composition which is more stably present. Many rust-preventive pigments that are also effective for compositions contain harmful substances such as dichromate and lead, and improving rust-preventive properties with them causes an additional problem of deteriorating the work environment. Let me.

[0006]

Means for Solving the Problems The present inventors have proposed an organosilicon compound having an aminoalkyl group and an alkoxysilyl group (hereinafter referred to as "organosilicon compound") and a metal having an epoxy resin as a main component. by specifying the amount of the specific metal phosphate anticorrosive composition, more solvent
Contains a monoalkyl ether of a dihydric alcohol as
The present inventors have found that the above-mentioned problems can be solved by using the above-mentioned structure, and have completed the present invention.

That is, the present invention relates to a method in which phosphoric acid Si, Zn or A is used with respect to 100 parts by weight of an organosilicon compound having an aminoalkyl group and an alkoxysilyl group and an epoxy resin.
l at least one metal phosphate selected from the group consisting of 1 to 200
A composition for metal rust prevention characterized by being blended in parts by weight
Products and their components are mono-alkoxy dihydric alcohols
The present invention relates to a composition for preventing metal rust, which is dissolved or dispersed in a solvent containing a ruether .

The organosilicon compound used in the present invention has both an aminoalkyl group and an alkoxysilyl group, and those described in the above-mentioned publications are similarly used, and are widely known as silane coupling agents. It is intended to include those that have.

Specific compounds include aminomethyltriethoxysilane, γ-aminopropyltriethoxysilane and γ-aminoisobutyltrimethoxysilane.
Aminoalkyl trialkoxysilane having three aminoalkyl groups and three alkoxysilyl groups; N- (β-
Aminoethyl) aminomethyltrimethoxysilane, N-
N- (β-amino) having an N- (aminoalkyl) aminoalkyl group and three alkoxysilyl groups such as (β-aminoethyl) aminomethyltriethoxysilane and N- (β-aminoethyl) aminopropyltrimethoxysilane N-aminoalkyltrialkoxysilane; aminoalkylalkyldialkoxysilane having one aminoalkyl group and two alkoxysilyl groups such as aminomethylmethyldiethoxysilane and γ-aminopropylmethyldiethoxysilane; (Β-aminoethyl)
An N- (aminoalkyl) aminoalkyl group such as aminopropylmethyldimethoxysilane and an N- (β-aminoalkyl) aminoalkylalkyldialkoxysilane having two alkoxysilyl groups; and two alkoxysilyl groups. Those having the above effects are particularly effective for improving rust prevention and are preferred for the present invention.

As the epoxy resin used in the present invention, those described in the above publications are similarly used. In the present invention, an epoxy resin having two or more hydroxyl groups in one molecule is preferable, Those based on the bisphenol A used are preferred.

Commercially available bisphenol A type epoxy resins include, for example, Epicoat 1001, 1004, 1
007 and 1009 (all manufactured by Yuka Shell Epoxy Co., Ltd.). Further, brominated epoxy resins in which part of the hydrogen atoms of the benzene ring of the bisphenol A type epoxy resin are substituted with bromine, such as Epicoat 1045 and Epicoat YL903 (all manufactured by Yuka Shell Epoxy Co., Ltd.) and the like.

Commercially available epoxy resins other than the bisphenol A type epoxy resin include dimer acid glycidyl ester type epoxy resins such as Epicoat 871.
(Manufactured by Yuka Shell Epoxy Co., Ltd.), and phenoxy resins, such as PKHH (manufactured by Union Carbide Corporation).

Other epoxy resins include, for example, glycidylamine type epoxy resin, novolak type epoxy resin, glycidyl ester type epoxy resin and the like.

The epoxy resin having two or more hydroxyl groups in one molecule in the present invention, particularly the bisphenol A type epoxy resin, is preferred because the aminoalkyl group of the organosilicon compound and the oxirane ring of the epoxy resin react very easily. When the number of hydroxyl groups in one molecule is less than two, the reaction rate is slow and it takes a long time to form a coating film. On the other hand, when there are two or more hydroxyl groups, the hydroxyl group of the epoxy resin is an organosilicon compound. It is considered that this greatly contributes to the reaction with, but a tough coating film is formed in a short time.

Further, a compound having an oxirane ring other than the epoxy resin can be added to the composition of the present invention as long as the performance of the composition of the present invention is not impaired. And organosilicon compounds such as-(3,4-epoxycyclohexyl) ethyltrimethoxysilane and γ-glycidoxypropyltrimethoxysilane. Furthermore, two or more (meth)
Compounds having an acryloyl group, such as compounds such as polyester (meth) acrylate, polyurethane (meth) acrylate, and epoxy (meth) acrylate, and compounds having two or more hydroxyl groups in one molecule, such as polyvinyl butyral resin and polyvinyl Formal resin,
Polyester resin, cellulose acetate butyrate,
A resin such as ethyl cellulose can be blended. Among them, a compound having two or more (meth) acryloyl groups in one molecule undergoes an addition reaction / crosslinking with an aminoalkyl group of the organosilicon compound of the present invention, and a resin having a hydroxyl group in the molecule is an organosilicon compound. It is useful because it forms a tough coating film by reacting with the alkoxysilyl group of the compound.

Examples of the metal phosphate according to the present invention include silicon polyphosphate, alkali metal salts of silicon polyphosphate, and silicon, zinc or aluminum salts of phosphoric acid such as zinc phosphate and aluminum phosphate. Used alone or in combination of two or more. In these phosphoric acids, the phosphoric acid component can exist in the form of orthophosphoric acid, metaphosphoric acid, pyrophosphoric acid, tripolyphosphoric acid, or other condensed phosphoric acid, but usually in a highly condensed form. It is desirable to be present. Among these metal phosphate salts, silicon phosphate is particularly preferred because it exhibits excellent rust prevention and good liquid storage stability when incorporated into the composition of the present invention. This is because the main ingredient is
It is represented by the following formula consisting of a phosphoric acid component (P ₂ O ₅ ) and a metal component (MO _{m / 2} ), and this component is characterized by having a sustained release of phosphoric acid.

MO _{m / 2} · nP ₂ O ₅ (M is a metal including Si, and m is a valence of the metal M. n is 0.1 to 0.1.
7 )

The details of the production method and properties of this silicon phosphate are described in US Pat. No. 4,018,816. Examples of commercially available products are MIZUKANEX-300, MIZU
KANEX-200 and MIZUKANEX-500 (all manufactured by Mizusawa Chemical Industry Co., Ltd.).

In the present invention, the solvent is effective for dissolving the resin component and stably dispersing the poorly soluble phosphoric acid compound in the liquid , and is particularly preferred for that purpose.
Casting is a solvent containing monoalkyl ethers of dihydric alcohols.

The monoalkyl ether of a dihydric alcohol refers to one having two or more alcoholic hydroxyl groups in one molecule and one of the hydroxyl groups being alkyl etherified, for example, ethylene glycol monomethyl ether. Ethylene glycol monoalkyl ethers such as ethylene glycol monoethyl ether and ethylene glycol monobutyl ether; ethylene glycol monomethyl ethers; propylene glycol monoalkyl ethers such as propylene glycol monomethyl ether, propylene glycol monoethyl ether and propylene glycol monobutyl ether; diethylene glycol Diethylene glycol such as monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, etc. Coal monoalkyl ethers; dipropylene glycol monoalethers such as dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monobutyl ether; and others, 3-methoxybutyl alcohol, 3-methyl-3-methoxybutyl Alcohol and the like. Among these monoalkyl ethers of dihydric alcohols, ethylene glycol monoalkyl ether and / or propylene glycol monoalkyl ether having good dissolving power are preferable, and more preferably, the boiling point at normal pressure is 100 ° C. or more and 220 ° C. The following are monomethyl and monoethyl ethers, which have an appropriate volatilization rate and good drying properties.

Dihydric alcohols and monohydric alcohols which have not been monoalkyletherified have problems such as poor solubility and gelation in a short time even if dissolved, and all hydroxyl groups are alkyletherified. Polyhydric alcohols have poor dispersion stability of pigments and have problems such as settling during storage, so that it is better to avoid using them.

It is also possible to use a mixture of one or more solvents other than the monoalkyl ether of polyhydric alcohol, for example, aromatic solvents such as toluene, xylene and mesitylene; acetone, methyl ethyl ketone,
Monoketone solvents such as methyl isobutyl ketone, cyclohexanone and isophorone; 1,3-diketone solvents such as acetylacetone, methyl acetoacetate and ethyl acetoacetate and β-ketocarboxylic acid ester solvents; ethyl alcohol, propyl alcohol, butyl alcohol and the like Alcohol solvents: Ester solvents such as ethyl acetate, butyl acetate, ethylene glycol monomethyl ether acetate, and propylene glycol monomethyl ether acetate. Such a solvent is preferably used in combination with a monoalkyl ether of a dihydric alcohol as long as the storage stability of the composition of the present invention and the drying property during coating are not impaired,
The monoalkyl ether of the dihydric alcohol is one in all solvents.
It is preferable to use it by containing 0% by weight or more, and more preferably 30% by weight or more. If the amount is less than this, there is a possibility that problems such as a decrease in storage stability such as a viscosity increase of the composition solution containing the pigment and a precipitation of the pigment may occur.

With respect to the compounding ratio of the composition of the present invention, the ratio of the organosilicon compound to the epoxy resin is 90/10 by weight.
５5/95, more preferably 6
0/40 to 10/90. If the ratio is out of this range, it is not preferable because the film-forming properties are reduced or the curing speed is slowed down at the time of coating on the object to be coated, and the durability of the coated film such as rust prevention is impaired.

The mixing ratio of the metal phosphate is 1/1 by weight relative to the total amount of the organosilicon compound and the epoxy resin.
00-200 / 100 der is, preferably 5/100
150/100. If the ratio is out of this range, the compounding effect such as low rust prevention property cannot be obtained or the strength of the coating film is remarkably reduced. The concentration when used as a solution is preferably from 10 to 90% by weight, more preferably from 10 to 60% by weight. If the ratio is out of this range, the liquid viscosity at the time of coating is not appropriate, and there is a possibility that the coating film after coating may have a problem.

The composition of the present invention is prepared by dissolving an organosilicon compound and an epoxy resin in a solvent containing a monoalkyl ether of a dihydric alcohol or a monoalkyl ether of a dihydric alcohol at room temperature or under heating, and then dissolving the metal phosphate. Is preferably used after being mixed and dispersed. Further, it is also possible to use the pigment after dispersing the pigment in a part or all of the organosilicon compound or a part of the epoxy resin.

The method of mixing and dispersing the pigments is a method known in the art. For example, a stirrer such as a paddle type mixer, a turbine type mixer, an impeller type mixer and a mill disperser such as a sand mill, a ball mill, an attriser and a roll mill are appropriately used. Can be selected and combined.

At the appropriate stage during production, other pigments such as carbon black, acetylene black,
Black pigments such as ram black, bone black and black iron oxide; white pigments such as titanium oxide, zinc white and lead white; extender pigments such as calcium carbonate, talc, clay, kaolin, alumina and silicic anhydride; zinc powder, aluminum Metal powders such as powders; and molybdenum disulfide, ethylene tetrafluoride powder, vinylidene fluoride powder, and the like can be added. In addition, various additives such as a viscosity modifier, an antifoaming agent, a siloxane bond condensation catalyst, an antioxidant, and an ultraviolet absorber can be used.

The composition of the present invention can be widely applied to metal substrates, and includes iron and iron alloys, aluminum and aluminum alloys, copper and copper alloys, zinc plating and zinc alloy plating, nickel plating, chromium plating, and cadmium. It is awarded for various plated substrates such as galvanized, especially galvanized, nickel-galvanized, iron-galvanized, tin-zinc plated by methods such as electroplating, hot-dip plating, mechanical plating, etc. It exhibits excellent rust prevention performance against zinc and zinc alloy plating such as plating, and metals that have been subjected to chromate treatment such as coloring, black, green, and colorless on the plating surface.

When the composition of the present invention is used in a state of being mixed and dispersed in a solvent, it can be easily applied to a metal substrate.
Spray coat, dip coat,
Known coating methods such as roll coating and brush coating can be applied. By removing the solvent at room temperature or under heating conditions after coating, a uniform coating film is formed and the object of the present invention can be achieved. The film thickness is 0.3 to 300 μm, preferably 1 to 100 μm
m, more preferably from 1 to 20 μm, and in particular, even if the film thickness is 10 μm or less, it is a great feature of the composition of the present invention that rust prevention can be remarkably imparted thereby.

[0030]

SUMMARY OF present compositions, the results studied intensively to improve the rust resistance of the composition proposed by the present inventors previously by incorporating metal phosphate specific amount, even a solvent
Contains monoalkyl ether of dihydric alcohol
Is obtained by achieved by using a thing, pigment dispersion stability of the composition, liquid viscosity stability is enhanced, excellent long term storage stability, and, if satisfactory coating which was applied to the application surface of the substrate By forming a film, the coating film performance can be remarkably improved, such as exhibiting excellent rust prevention properties.

The reason why the composition of the present invention exhibits excellent rust prevention and liquid storage stability is not clear, but is presumed as follows.

After the coating film is formed, the phosphoric acid content of the metal phosphate is eluted into the coating film over time, and the chromate component on the substrate surface
Reacts with inorganic components such as zinc components to suppress corrosion. In the liquid composition, the phosphoric acid component of the metal phosphate reacts with the active aminoalkyl group of the organosilicon compound and suppresses the reaction with the oxirane ring of the epoxy resin. Similarly, the hydrolysis reaction of the alkoxysilyl group of the organosilicon compound and the condensation between the organosilicon compounds are suppressed.

Hereinafter, a specific example will be described.

[0034]

EXAMPLES Example 1 Epicoat 1004 (manufactured by Yuka Shell Epoxy Co., Ltd.)
A solution prepared by dissolving 66.4 parts by weight (hereinafter referred to as "parts") in 300.0 parts of a 1/1/1 (weight ratio) mixed solvent of propylene glycol monomethyl ether / xylene / methyl isobutyl ketone was added with 30 parts of zinc phosphate. After stirring and mixing 0 parts and 10.0 parts of carbon black # 1000 (manufactured by Mitsubishi Kasei Kogyo Co., Ltd.), glass beads were added and dispersed with a paint shaker to obtain a black dispersion. To this, 50.0 parts of methyl acetoacetate and 44.2 parts of γ-aminopropyltriethoxysilane were added and mixed to obtain a composition having a black appearance. (Experiment number 1)

Examples 2 to 5 and Comparative Examples 1 to 8 In the same manner as in Example 1 except that zinc phosphate of Experiment No. 1 was used instead of Table 1
And the compound concentration in the composition is 3
The composition was prepared by changing the amount of the mixed solvent to be 0% by weight. (Experiment numbers 2 to 13)

These compositions were subjected to the following tests. (1) Liquid stability test 400 cc of each of these compositions was placed in a tin can made of tin,
After being immersed in a water bath and allowed to stand for one month, changes in the properties of the composition were visually observed while stirring with a spatula, and the following scores were given. ：: Uniform state without sediment or gelation. Δ: A state in which sediment exists but becomes uniform after stirring. ×: A state in which a sediment or a gel exists and is not uniform even when stirred.

(2) Adhesion test Electrogalvanized black chromate treated plate (70 × 150 ×
These liquid compositions were dried by heating at 100 ° C. for 20 minutes so as to give a dry coating amount of 5 g / m ² . After eleven rods were placed on the surface of the coating film at intervals of 1 mm with a cutter knife so as to reach the metal substrate, an adhesion peeling test was performed using a cellophane tape. The peeled surface was observed and rated as follows. ○: No peeling ×: Peeling

(3) Salt spray test After a cross cut reaching the substrate was made with a cutter knife on the coating surface of the test plate prepared in the same manner as in (2) above,
Seal the end face of the test plate and perform salt spray test (JIS-Z-2
371) Subjected to 600 hr. The state of rusting of the cross cut portion was observed and expressed by the following score. ：: No rusting was observed. Δ: One-sided rust width (bulging width) 2 mm or less. X: One-sided rust width (bulging width) 2 mm or more.

[0039]

[Table 1]

[0040]

According to the present invention, a coating film is formed simply by immersing a metal substrate in a solution of the composition of the present invention and air-drying. 1 coating
Even with a thin film thickness of 10 μm, it shows good rust prevention and excellent aesthetics, and does not cause various troubles in the process due to the increase in the thickness of the base material by the coating film, It has excellent storage stability and can exhibit stable coating performance. For these reasons, the present invention provides an extremely simple rust prevention method for chromate-treated materials of zinc plating and zinc alloy plating, which are widely used in industry, and greatly contributes to each industry.

Continuation of the front page (56) References JP-A-59-96279 (JP, A) JP-A-52-28529 (JP, A) JP-A-62-83430 (JP, A) JP-A-3-121171 (JP) , A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C23F 11/00 B05D 5/00 C09D 5 / 08,163 / 00 C08J 7/04

Claims (2)

(57) [Claims] 1. A 100-fold sum of organic silicon compound having an aminoalkyl group and an alkoxysilyl group and an epoxy resin
1 part selected from the Si, Zn or Al salt of phosphoric acid
1 to 200 parts by weight of at least one kind of metal phosphate
Metal anticorrosive composition, characterized in that that. 2. Each component is a monoalkyl dihydric alcohol.
That it is dissolved or dispersed in a solvent containing ether
The metal rust preventive composition according to claim 1, wherein