JPH03121171A - Metal rustproofing composition - Google Patents

Abstract

PURPOSE:To prevent the deterioration of the stability of a composition due to incorporation of a pigment by using a dihydric alcohol monoalkyl ether as the solvent in a metal rustproofing composition composed mainly of a specified organosilicon compound and an epoxy resin and having a pigment incorporated therein. CONSTITUTION:This metal rustproofing composition is made by mixing an organosilicon compound having an alkylamino group and an alkoxysilyl group, an epoxy resin having at least two hydroxyl groups in the molecule, a pigment, and a dihydric alcohol monoalkyl ether. The organosilicon compounds include those widely known as the silane coupling agent. As the epoxy resin, bisphenol A and F epoxy resins are preferably used. As the dihydric alcohol monoalkyl ether, an ethylene glycol monoalkyl ether and a propylene glycol monoalkyl ether, which have good dissolving power, are preferably used.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Object of the invention "Field of industrial application" The present invention relates to a composition for preventing metal rust, and more specifically to a composition having good storage stability over a long period of time at room temperature. ,
The present invention relates to a composition for preventing metal rust, which forms an effective film when applied to a metal surface by moisture present in the atmosphere or by slight heating, and exhibits good rust prevention properties. In particular, zinc plating, nickel/zinc plating,
It is a rust-preventing composition suitable for zinc and zinc alloy plating such as iron/zinc plating, tin/zinc plating, and metals whose surfaces have been subjected to chromate treatment. It can be widely used in various industrial fields that use.

"Prior Art" Many treatment agents, paints, etc. have been used for the purpose of protecting metal surfaces from various corrosive environments. Among these, paints that form a film and cure at room temperature or with slight heating are widely praised for their ability to save resources and simplify processes in terms of thermal energy. Examples of these paints are:
For example, two-component paints such as polyurethane and epoxy paints,
Examples include air-drying paints such as alkyd-based and polybutadiene-based paints, and moisture-curing paints such as silicone-based and various modified silicone-based paints.

``Problems to be Solved by the Invention'' However, paints that can be formed into a film or cured at room temperature or by slight heating have the following problems.

In other words, two-component curing paints form a dense film and have excellent rust prevention properties, but they have operational limitations such as the complexity of measuring and mixing the curing agent and a short pot life. Most air-drying paints form coating films with excellent water resistance, but residual unsaturated bonds can reduce the antioxidant properties and weather resistance of the coating film. Furthermore, silicone-based moisture-curing paints, which have excellent weather resistance and heat resistance, have drawbacks in storage stability and rust prevention properties of the paint film.

In order to solve these problems, the inventors of the present invention proposed in Japanese Patent Application No. 57-203358 that the film thickness is much thinner than that of ordinary coatings, it exhibits excellent rust prevention properties, and it can be maintained at room temperature. We have proposed a curable metal rust-preventing composition, which can be colored with various pigments for the purpose of imparting aesthetics, or may be colored with a rust-preventive agent or rust-preventive pigment to further improve its rust-preventive properties. If a lubricating substance is added for the purpose of improving the surface properties of the paint film, the active groups on the surface of particles such as pigments and the adsorbed moisture on the surface of the particles may react with the constituent components of the composition. However, there is a problem that stability may be impaired.

The inventors of the present invention have conducted various studies with the aim of solving this problem.

(b) Structure of the invention "Means for solving the problem" As a result of studies by the present inventors, an organosilicon compound having an aminoalkyl group and an alkoxysilyl group (hereinafter referred to as "organosilicon compound") was proposed earlier. In metal rust prevention compositions whose main component is an epoxy resin having two or more hydroxyl groups in one molecule (hereinafter referred to as "epoxy resin"), a decrease in stability that occurs due to the addition of pigments may occur due to the presence of certain solvents. That is, the inventors have discovered that this can be prevented by using a monoalkyl ether of a dihydric alcohol as a solvent, and have completed the present invention.

That is, the present invention provides a metal protective material comprising an organosilicon compound having an aminoalkyl group and an alkoxysilyl group, an epoxy resin having two or more hydroxyl groups in one molecule, a pigment, and a monoalkyl ether of a dihydric alcohol. This invention relates to a rust composition.

OOrganosilicon compound The organosilicon compound used in the present invention has both an aminoalkyl group and an alkoxysilyl group,
This includes those widely known as silane coupling agents, as explained in detail in the previous proposal.Specific compounds include aminomethyltriethoxysilane, γ-aminopropyltriethoxysilane, 1 such as ethoxysilane, γ-aminoisobutyltrimethoxysilane, etc.
Aminoalkyltrialkoxysilane having 3 aminoalkyl groups and 3 alkoxysilyl groups; N-(β-
aminoethyl)aminomethyltrimethoxysilane, N-
N-(β- aminoalkyl) aminoalkyltrialkoxysilane; aminoalkylalkyldialkoxysilane having one aminoalkyl group and two alkoxysilyl groups such as aminomethylmethyljethoxysilane, T-aminopropylmethyljethoxysilane; N- N-(β-aminoalkyl)aminoalkylalkyldialkoxysilanes having an N-(aminoalkyl)aminoalkyl group and two alkoxysilyl groups, such as (β-aminoethyl)aminopropylmethyldimethoxysilane, etc. Those having two or more alkoxysilyl groups are preferred in order to improve rust prevention properties.

O Epoxy resin The epoxy resin having two or more hydroxyl groups in one molecule used in the present invention is also explained in detail in the previous proposal, and as a preferable epoxy resin for the present invention, bisphenol A based on bisphenol A is used. and F-type epoxy resins, and these resins are commercially available with various properties, such as Epicoat 1001.1004.1007.1009 (manufactured by Yuka Shell Epoxy), etc. Used in the present invention. -Other examples include brominated epoxy resins in which some of the hydrogen atoms in the benzene ring of bisphenol A epoxy resins are replaced with bromine, such as Epicote 1045,
Dimer acid-based glycidyl ester type epoxy resin such as Epicoat YL903 (manufactured by Yuka Shell Epoxy), such as Epicoat 871 (manufactured by Yuka Shell Epoxy)
etc., phenoxy resins such as PKHH (manufactured by Union Carbide Corporation) and the like.

Other resins or compounds may be used in combination with the above epoxy resin as long as they do not impair the performance of the composition of the present invention. Resin having an oxirane ring other than (β-
Organosilicon compounds such as (3,4-epoxycyclohexyl)ethyltrimethoxysilane, T-glycidoxypropyltrimethoxysilane; polyvinyl butyral resin, polyvinyl formal resin, polyester resin,
Resins having hydroxyl groups in their molecules, such as cellulose acetate butyrate and ethyl cellulose, can be used in combination. Among these, resins having hydroxyl groups in their molecules are particularly useful because they react with alkoxysilyl groups of organosilicon compounds and form tough coating films.

Monoalkyl ether of dihydric alcohol The monoalkyl ether of dihydric alcohol used as a solvent in the present invention has two alcoholic hydroxyl groups in one molecule, and one of the hydroxyl groups is an alkyl ether. Specifically, ethylene glycol monoalkyl ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and ethylene glycol motsubutyl ether: propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene Propylene glycol monoalkyl ethers such as glycol monobutyl ether; diethylene glycol monoalkyl ethers such as diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether; dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monobutyl ether and other dipropylene glycol monoalkyl ethers; other examples include 3-methoxybutyl alcohol, 3-methyl-3-methoxybutyl alcohol, and the like.

In the present invention, various monoalkyl ethers of dihydric alcohols such as those mentioned above are used, but ethylene glycol monoalkyl ethers and propylene glycol monoalkyl ethers having good dissolving power are preferred for the present invention, and particularly , the boiling point at normal pressure is 100
Monomethyl, monoethyl ether, etc., which have a temperature of .degree. C. or more and 220.degree. C. or less, have an appropriate volatilization rate and have good drying properties, and are therefore preferable.

Dihydric alcohols and monohydric alcohols that have not been converted into monoalkyl ethers have problems such as poor solubility and gelation in a short period of time even when dissolved. It cannot be used as a substitute. Further, dihydric or polyhydric alcohols in which all of the hydroxyl groups have been converted into alkyl ethers cannot be used as substitutes because they have problems such as poor pigment dispersion stability and sedimentation during storage.

In the present invention, it is possible to mix and use one or more other solvents with the monoalkyl ether of dihydric alcohol, such as 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; β-ketocarboxylic acid ester melts; ethyl alcohol, propyl alcohol, butyl alcohol, etc. Alcohol solvents; ester solvents such as ethyl acetate, butyl acetate, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, etc. can be used in combination.

These solvents are used in combination with the monoalkyl ether of dihydric alcohol to the extent that they do not impair the storage stability of the composition of the present invention or the drying properties during coating. 10% by weight in total solvent
It is preferable to use the above-mentioned components in combination, and it is particularly preferable that the amount is 30% by weight or more. If the amount of the monoalkyl ether of dihydric alcohol is less than 10% by weight, problems such as thickening of the composition solution containing the pigment, precipitation of the pigment, and other problems such as a marked decrease in storage stability. may occur.

Among the above-mentioned solvents, when a dicarbonyl compound such as a 1,3-diketone solvent or a β-ketocarboxylic acid ester solvent is used in combination, it reacts with the aminoalkyl group of the organosilicon compound in the composition of the present invention to form an imine. It forms a compound and exists stably with the epoxy resin having an oxirane ring during storage, and once it is applied to the substrate, the organosilicon compound is regenerated by moisture in the atmosphere, and the organic silicon compound has an oxirane ring. Since it has the property of reacting with epoxy resin and forming a coating film, it is effective for increasing the stability of the composition of the present invention, so it is a compound that is preferably used in combination, but the amount used is Because of the above-mentioned properties, the amount is preferably 5 to 20% by weight based on the total solvent.

O Pigment As the pigment used in the present invention, any pigment that has been widely praised in the field can be applied, but for the present invention, it is preferable to use a pigment with a secondary particle size of 10 μm or less, and specifically, Black pigments such as carbon black, acetylene black, lamb black, bone black, and black iron oxide; White pigments such as titanium oxide, zinc white, and lead white; Antirust pigments such as zinc chromate, strontium chromate; calcium carbonate, Extender pigments such as talc, clay, kaolin, alumina, and silicic anhydride; metal powders such as zinc powder and aluminum powder; and others such as molybdenum disulfide, ethylene tetrafluoride powder, and vinylidene fluoride powder.

In the present invention, various pigments such as those mentioned above are used, but carbon black, which gives a black appearance, aluminum powder, chromate, or fine particulate silicic acid, which improves rust prevention, are used to improve storage stability and This is preferable because it exhibits a remarkable effect on coating film performance.

For more information on carbon black, see the Encyclopedia of Chemical Technology.
pedia of Chemical Technology
ogy (Second Edition) Vol, 4
p., 243-282), and is classified into channel black, furnace black, thermal black, etc. Furnace black is preferred in the composition of the present invention from the viewpoint of coloring degree and dispersion stability.

Aluminum powder is produced by pulverizing aluminum foil, spraying molten aluminum, etc., and from the viewpoint of safety during handling, it is preferably used in the form of aluminum paste, which is kneaded with a solvent or oil.

Zinc chromate is produced by the reaction between chromic anhydride and potassium dichromate or zinc white, and strontium chromate is produced by the reaction between strontium sulfate and sodium dichromate.

Fine particulate silicic anhydride is called fumed silica and hydrophobic silica, which is obtained by treating fumed silica with silane or polysiloxane, and is described in Encyclopedia of Chemistry.
Mical Technology (Second E)
The details are described in Vol. 18, p. 6l-72).

O blending ratio The blending ratio of the composition of the present invention is preferably such that the ratio of organosilicon compound to epoxy resin is 90/10 to 5/95 by weight, and more preferably 60/40 to 10/95.
It is 90. If the ratio is outside this range, it is not preferable because there is a risk that the film-forming property will be reduced or the curing speed will be slowed, which may impair the durability of the coating film such as rust prevention.

In addition, the proportion of the pigment is 1/100 to 200/100 by weight with respect to the total amount of the organosilicon compound and the epoxy resin.
It is preferable that it is, and more preferable is 5/100~
It is 150/100. If it deviates from this ratio, the effect of blending the pigment may not be obtained or the strength of the coating film may decrease significantly, which is not preferable.

Further, the concentration of nonvolatile matter in the solution is preferably 10 to 9.
The solvent is used in an amount of 0% by weight, more preferably 10 to 60% by weight. If this ratio is exceeded, the viscosity of the liquid during coating will not be appropriate and there is a risk that defects may occur in the coated film after coating.

O adjustment method The composition of the present invention comprises an organosilicon compound and an epoxy resin,
It is easily produced by dissolving the monoalkyl ether of a dihydric alcohol or a solvent containing the monoalkyl ether of a dihydric alcohol at room temperature or under heating, and then mixing and dispersing the pigment. Alternatively, it may be manufactured by adding part or all of the organosilicon compound or part of the epoxy resin after dispersing the pigment.

As a method for mixing and dispersing pigments, methods known in the art may be applied (e.g., stirrers such as paddle mixers, turbine mixers, impeller mixers, mill dispersion machines such as sand mills, ball mills, attrizers, roll mills, etc.). can be appropriately selected and combined and mixed and dispersed.

Further, various additives such as a viscosity modifier, an antifoaming agent, a siloxane bond condensation catalyst, an antioxidant, and an ultraviolet absorber may be added at an appropriate stage during production.

O Applicable Substrates The composition of the present invention can be widely applied to metal substrates, including iron and iron alloys, aluminum and aluminum alloys, copper and copper alloys, zinc plating and zinc alloy plating, nickel plating, chrome plating, and cadmium plating. The award is given to base materials with various types of plating such as plating, especially zinc plating, nickel/zinc plating, iron/zinc plating, tin/zinc plating applied 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 whose surfaces have been subjected to chromate treatment such as colored, black, green, and colorless plating.

○Application method Since the composition of the present invention is in the form of a solution, it can be easily applied to metal substrates.
Known coating methods such as dip coating, roll coating, and brush coating can be applied. After coating, by removing the solvent at room temperature or under heated conditions, a uniform coating film is formed and the object of the present invention can be achieved. The film thickness is 1 to 300 μm, preferably 1 to 100 μm, more preferably 1 to 2 oI1 m
It is a major feature of the composition of the present invention that it can provide remarkable rust prevention even with a film thickness of 10 um or less.

"Function" The present invention aims to improve the dispersion stability of the composition previously proposed by the present inventors when blending pigments. The pigment dispersion stability and liquid viscosity stability of the composition are improved, the composition has excellent long-term storage stability, and it can be applied to the surface of the applied substrate. When processed, a good coating film can be formed and coating film performance such as rust prevention can be significantly improved.

Although the reason why the composition of the present invention exhibits excellent liquid storage stability is not clear, the following reasons are presumed.

The hydroxyl group of the monoalkyl ether of the dihydric alcohol covers the active groups (OH group, COOH group, etc.) on the pigment surface, suppressing the reaction or hydrogen bonding with the alkoxyxylyl group of the organosilicon compound, and on the other hand, the alkyl ether group portion improves wettability with organic resin components.

The hydroxyl group of the monoalkyl ether of the dihydric alcohol undergoes transesterification with the alkoxysilyl group of the organosilicon compound, resulting in hydrolysis of the organosilicon compound and condensation of the organosilicon compounds due to moisture present in the liquid and moisture adsorbed on the pigment surface. suppress.

The hydroxyl group of the monoalkyl ether of the dihydric alcohol forms a hydrogen bond with the aminoalkyl group of the organosilicon compound,
Suppresses the reaction between the aminoalkyl group and the oxirane ring of the epoxy resin.

Moreover, the reason why bisphenol A type epoxy resin having two or more hydroxyl groups in one molecule in the present invention is preferable is as follows.
The aminoalkyl group of the organosilicon compound and the oxirane ring of the epoxy resin react very easily, and 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. This is thought to be because when the epoxy resin has two or more hydroxyl groups, a tough coating film is formed in a short time, that is, the hydroxyl groups of the epoxy resin greatly contribute to the reaction with the organosilicon compound.

"Examples and Comparative Examples" Examples 1 to 6 66.4 parts by weight (hereinafter referred to as parts) of an epoxy resin (Epicoat 1004 manufactured by Yuka Shell Epoxy), 91.8 parts of ethylene glycol monoethyl ether, and 91 parts of toluene.
．． Carbon black (manufactured by Mitsubishi Chemical Industries, Ltd. #
1000) were stirred and mixed and dispersed using a ball mill type disperser to obtain a black dispersion. 44.2 parts of T-aminopropyltriethoxysilane was added and mixed to obtain a composition.

(Example 1) In the same manner, the solvent of Example 1 was mixed with 110.0 parts of propylene glycol monomethyl ether and 5 parts of acetylacetone.
A composition was obtained by replacing 4.9 parts of xylene with 110.0 parts of xylene. (Example 2) A composition was obtained in the same manner as in Example 1 except that the solvent was replaced with 3-methyl-3-methoxybutyl alcohol III, O parts, 110.0 parts of cyclohexanone, and 54.9 parts of xylene. Ta. (Example 3) In a similar manner, 7.2 parts of carbon black as a pigment in Example 1 was combined with 3.8 parts of zinc chromate (ZTO manufactured by Nippon Inorganic Chemical Industry Co., Ltd.) as a pigment to obtain a composition. Ta. (Example 4) In a similar manner, 7.2 parts of carbon black as a pigment in Example 1 was combined with 2.0 parts of fumed silica (Aerosil R972: manufactured by Nippon Aerosil Industries) as a pigment to obtain a composition. Ta. (Example 5) A composition was obtained in the same manner as in Example 1, except that 30.3 parts of aluminum paste (0100NA manufactured by Toyo Aluminum Co., Ltd., non-volatile content: 66% by weight) was used in place of the carbon black pigment. (Example 6) These solution compositions were subjected to the following tests.

(1) Pour 400 cc of each solution in a liquid state into a tin oil can and hold at 40°C.
After immersing the solution in a water tank and leaving it for one month, changes in the properties of the solution were observed.

(2) Salt water spray test A galvanized yellow chromate treated test plate (70 x 150 x 0.8) dip-coated in each solution was heated and dried at 80°C for 10 minutes, and then the salt water spray test (JIS-Z-2371
) 600 hours.

The results of these tests are shown in Table 1.

Example 7 A resin consisting of 44.2 parts of epoxy resin (Epicoat 1004, manufactured by Yuka Shell Epoxy) and 22.2 parts of polyvinyl butyral resin (S-LEC BLI, manufactured by Sekisui Chemical) was mixed with 184.6 parts of propylene glycol monomethyl ether,
45.7 parts of xylene, 45.7 parts of methyl isobutyl ketone
Further, 7.2 parts of carbon black (#1000 manufactured by Mitsubishi Chemical Industries, Ltd.) was dissolved in a mixed solvent consisting of 1.5 parts and 7.2 parts of carbon black (#1000 manufactured by Mitsubishi Chemical Industries, Ltd.) was stirred and mixed, and the mixture was dispersed using a sand mill type disperser to obtain a black dispersion. To this, γ-aminopropyltriethoxysilane 44
．． Two parts were added and mixed to obtain a composition. This composition was evaluated using the test method described above. The results are also shown in Table 1.

-m- (Hereinafter, blank) -11 Comparative Examples 1 to 5 In the same manner as in Example 1, the mixed solvent of Example 1 was mixed with 8.9 parts of ethylene glycol monoethyl ether and 1 part of toluene.
A composition was obtained by replacing 33.0 parts of methyl ethyl ketone with 133.0 parts of methyl ethyl ketone. (Comparative Example 1) A composition was obtained in the same manner as in Example 1 except that the mixed solvent of Example 1 was replaced with 91.8 parts of ethylene glycol, 91.8 parts of toluene, and 91.8 parts of methyl ethyl ketone. (Comparative Example 2) In the same manner as in Example 1, the mixed solvent of Example 1 was mixed with 91.8 parts of ethylene glycol diethyl ether and 9 parts of toluene.
A composition was obtained by replacing 1.8 parts of methyl ethyl ketone with 91.8 parts of methyl ethyl ketone. (Comparative Example 3) A composition was obtained in the same manner as in Example 1 except that the mixed solvent of Example 1 was replaced with 91.8 parts of n-butanol, 91.8 parts of toluene, and 91.8 parts of methyl ethyl ketone. (Comparative Example 4) In addition, in the same manner, 8.9 parts of ethylene glycol monoethyl ether and 133 parts of toluene were added to the mixed solvent of Example 1.
．． 0 parts and 133° of methyl ethyl ketone in place of 0 parts,
Further, 3.8 parts of zinc chromate (ZTo, manufactured by Japan Inorganic Chemical Industry Co., Ltd.) was blended together with 7.2 parts of carbon black to obtain a composition. (Comparative Example 5) These compositions were evaluated using the same test method as in the examples.

The test results are shown in Table 2.

-m- (hereinafter referred to as margin) -11 (c) Effects of the invention Metal substrates immersed in the composition of the present invention form a coating film simply by air drying, and can be very easily and easily coated with good protective properties. The coating film formed with rust resistance shows good rust prevention properties and excellent aesthetics even at a thin film thickness of 1 to 10 μm, and this work is caused by the increase in the thickness of the base material due to the coating film. In addition, the composition of the present invention does not cause various troubles in the process, and the composition of the present invention has excellent storage stability and can consistently exhibit stable coating film performance. The present invention can provide an extremely convenient rust prevention method for chromate-treated materials such as plating and zinc alloy plating, and will greatly contribute to various industries.

Claims (1)

[Claims] 1. A metal rust-preventing composition comprising an organosilicon compound having an aminoalkyl group and an alkoxysilyl group, an epoxy resin having two or more hydroxyl groups in one molecule, a pigment, and a monoalkyl ether of a dihydric alcohol. .