JPH10183383A - Corrosion inhibitor composition for coating oily surface - Google Patents

Abstract

PROBLEM TO BE SOLVED: To exhibit excellent rust preventing property and high adhesiveness by containing an epoxy resin derived from bisphenol A and/or bisphenol F, a defoaming agent, a plasticizer, a reactive diluent and a latent hardening agent of the epoxy resin. SOLUTION: The epoxy resin in the objective composition can be used alone or in combination and has 2 epoxy groups in the resin molecule is mentioned. A defoaming agent and a mixed agent of the plasticizer with the reactive diluent are incorporated by 0.1-10 pts.wt. and 1-20 pts.wt., respectively per 100 pts.wt. epoxy resin. As the defoaming agent, a silicone, a vinyl polymer, an acrylic polymer or a copolymer of the vinyl polymer and the acryl polymer is used. As the concrete example of the plasticizer, tributyl phosphate, tri-2-ethyl hexyl phosphate and tricresyl phosphate are mentioned. As the reactive diluent, n-butyl glycidyl ether and diglycidyl ether are used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating type rust preventive, and more particularly, to a one-part type thermosetting epoxy resin composition, which is provided with press oil or rust preventive oil. By applying to the treated steel plate, oil-plated aluminum alloy plate, or oil-plated steel plate, it exhibits excellent rust prevention and adhesion, and is particularly suitable for use as an anti-rust agent for ordinary steel plates for automobiles. The present invention relates to a rust inhibitor composition for use.

[0002]

2. Description of the Related Art Up to now, there has been a demand for improvement of rust resistance of an automobile body.
For example, steel sheets used for fenders, doors, body sides, etc. are made of various rust-resistant steel sheets having high rust resistance, such as zinc-nickel plated steel sheets and steel sheets coated with an organic coating on plated steel sheets. ing.

However, in recent years, by improving the body structure, improving the electrodeposition paint and the coating method, the throwing power of the paint has been improved, and a part requiring a rust-proofed steel sheet is, for example, in the case of a body side panel, There is only a so-called bag structure, which is difficult to paint on the body structure. Therefore, in such a case, it is sufficient to use the rust-prevention treated steel plate only for the necessary parts such as the sill, but in many cases, the plate cannot be divided and joined for design reasons.
Actually, many vehicles use excessively the rust-prevention-treated steel sheet, causing a great deal of waste.

[0004] In order to eliminate such waste, a method of applying a rust inhibitor to only a necessary portion of a normal steel sheet and performing a rust prevention treatment has been considered, and some materials applicable to the present application have been proposed. For example, a mixture of a urethane-modified epoxy resin and a latent curing agent with a rust-preventive pigment or a metal component (Japanese Patent Laid-Open No. 60-206882), a specific rubber-modified epoxy resin, an aromatic epoxy resin, a latent curing agent, Containing conductive carbon black (Japanese Patent Laid-Open No. Sho 62-5338)
No. 7) and a mixture of a mixture of a urethane-modified epoxy resin and a rubber-modified epoxy resin with a latent curing agent and a specific rust preventive pigment (Japanese Patent Application Laid-Open No. 1-11971).

[0005]

However, the above-mentioned materials were originally developed for use as an adhesive and do not always satisfy the conditions as a rust preventive that can be applied. For example, the most important thing as a coating type rust preventive is to secure the rust prevention of the base material. It is necessary that a thin film can be easily applied and formed without causing the problem, and that the applied film has a function of preventing contact between the steel substrate and moisture.

However, the above-mentioned material is, for example, 300 μm
When applying the following thin film to the oil-side steel plate, these materials are originally developed as a high-viscosity adhesive that can be applied to the oil-side steel plate in a bead shape with a thickness of 2 to 3 mm. There was a problem that it was not possible to apply the varnish. On the other hand, even if diluted and coated with an organic solvent such as xylene,
Due to the high viscosity, air bubbles are involved and generate air bubbles on the surface of the base material, and rust is generated particularly from the air bubbles generated at the end of the coating film, which causes the rust to expand and the rust-prevention property is significantly reduced. .

The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to provide various kinds of steel sheets and various aluminum alloy sheets to which press oil or rust-preventive oil is adhered. An object of the present invention is to provide a rust preventive composition for oil surface application that exhibits excellent rust prevention and high adhesion.

[0008]

Means for Solving the Problems The present inventors have made intensive studies to achieve the above object, and as a result, by adding a specific epoxy resin, a defoaming agent, etc., they have excellent rust prevention and excellent adhesion. It has been found that a coating-type rust preventive having a high value is obtained, and the present invention has been completed.

That is, the coating type rust preventive composition of the present invention comprises an epoxy resin derived from bisphenol A and / or bisphenol F, a defoamer, a plasticizer, a reactive diluent, and an epoxy resin. It contains a latent curing agent and does not generate rust after 400 hours of durability in a salt spray test.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the rust composition for oil surface application of the present invention will be described in detail. As described above, the rust preventive composition of the present invention contains a predetermined epoxy resin, a defoaming agent, a plasticizer, a reactive diluent, and a latent curing agent. Here, as the epoxy resin, an epoxy resin derived from bisphenol A and / or bisphenol F and epichlorohydrin or a mixture thereof can be used, and an epoxy resin having at least two epoxy groups in the epoxy resin molecule used. Is mentioned.

Next, the above-mentioned defoaming agent concentrates on the surface of the air bubbles entrained at the time of application, and when the coating film is uncured and has fluidity, or when the fluidity increases upon heating, the surfactant is used as a surfactant. It exerts an effective function, reduces the membrane surface tension around bubbles, and promotes degassing.

[0012] The thin film near the boundary of the coating film is thin, and the air bubbles existing in the thin film portion are apt to be invaded by moisture through the thin film. In particular, the air bubbles existing on the surface of the base material are covered with a rust inhibitor film. Since it has not been rusted, it rusts due to the invading water, and the rust spreads from here. In addition, bubbles existing in the film generate a side when heated, form a path of moisture intrusion, and become a factor of deteriorating rust prevention. It functions to quickly deaerate air bubbles in the film and remarkably enhance the rust prevention of the coating film.

It is preferable that the defoaming agent is usually added in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the epoxy resin. If the amount is less than 0.1 part by weight, the adhesion between the coating film and the base material is reduced, and moisture permeation from the joint surface is caused, and the rust prevention property is sometimes undesirably reduced.

The components constituting the defoaming agent include lower alcohols, higher fatty acid metal soaps, lower alkyl phosphates, silicones, vinyl polymers, acrylic polymers, vinyl polymers and acrylic polymers. Among them, silicone, vinyl-based polymer, acrylic-based polymer, and copolymer of vinyl-based polymer and acrylic-based polymer can be preferably used.

Further, as the above-mentioned vinyl polymer and acrylic polymer, the following general formula: CH ₂ ＣＲCR ₁ -OR ₂ (wherein R ₁ represents -H or -CH ₃ , R ₂ represents —COOR ₃ or —O—R _{3 in} which —R ₃ is an alkyl group, an aryl group, a nitrile group, an oxyethylene group, or the like.) And a vinyl polymer represented by the following general formula: An acrylic polymer represented by CH ₂ ＯＲCR ₄ —COOR ₅ (wherein R ₄ represents —H or —CH ₃ , and R ₅ represents an alkyl group or an aryl group) is particularly preferable. As the copolymer, a copolymer of a vinyl polymer and an acrylic polymer is particularly preferable.

The vinyl polymer or the acrylic polymer can be used alone or as a mixture of two or more of them, and various vinyl polymers and acrylic polymers can be mixed and used. It is also possible to use.

Next, the plasticizer has high compatibility with press oil and rust preventive oil, and has an effect of preventing oil repellency, forming a continuous coating film and improving rust preventive property. Further, it can be easily mixed with the above epoxy resin, and has an effect of lowering the viscosity of the obtained rust preventive agent. Therefore, the work at the time of application is facilitated, and the flowability is imparted, so that the coating is performed after the application. It has the effect of promoting the flattening of the gaps between the films and the thin film portion and further increasing the rust prevention. Specific examples of such a plasticizer include tributyl phosphate, tri-2-ethylhexyl phosphate, and tricresyl phosphate.

Next, the reactive diluent is well compatible with the above epoxy resin to lower the viscosity, enhance the application of the rust inhibitor, and react with the epoxy resin to form a coating film and a substrate. It has the effect of improving the adhesion.

Examples of the reaction diluent include n-butyl glycidyl ether, allyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, glycidyl methacrylate, tertiary carboxylic acid glycidyl ester, diglycidyl ether, (poly)
Ethylene glycol glycidyl ether, (poly) ethylene glycol diglycidyl ether, diglycidyl aniline, phenoxyalkyl monoglycidyl ether,
Examples thereof include 1,6 hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, and polyoxyalkylene glycol diglycidyl ether. In particular, n-butyl glycidyl ether and diglycidyl ether can be preferably used.

As described above, in the rust preventive of the present invention, a plasticizer and a reactive diluent are used in combination. The reason for this is that when the plasticizer alone is blended, the adhesion between the substrate and the coating film is maintained. The adhesion of the epoxy resin decreases, the adhesion of the coating film decreases, the film peels off, etc., and the rust prevention property decreases.On the other hand, if only the reactive diluent is used, the affinity with oil is low, This is because repelling occurs to cause a decrease in oil-surface adhesiveness, resulting in a decrease in rust prevention. By using a plasticizer and a reactive diluent together, oil repelling can be prevented, and good oil surface adhesion is ensured.
Rust prevention can be maintained.

Further, in the rust preventive of the present invention, it is preferable to add a mixture of a plasticizer and a reactive diluent in a range of 10 to 150 parts by weight based on 100 parts by weight of the epoxy resin. If the amount is more than 150 parts by weight, the bond between the substrate and the rust-preventive film is weakened, and the adhesive strength is remarkably reduced, so that the rust-preventive property may be lowered. If the amount is less than 10 parts by weight, the compatibility with the oil surface becomes low, oil repelling is generated, and rust is generated from the repelled portion, and the rust prevention property may be remarkably reduced. Furthermore, because of the high viscosity, defoaming of bubbles entrained at the time of application is inhibited, a foam is generated, a path for moisture intrusion is formed, rust prevention is significantly reduced, and coating workability is also significantly reduced. Yes,
Not preferred.

Next, the latent curing agent can be selected from known curing agents which exhibit an effect by heating. For example, dicyandiamide, 4,4'-cyanodiphenylsulfone, 2-n Imidazole derivatives such as -pentadecyl imidazole; dibasic acid dihydrazides such as adipic dihydrazide; N, N'-dialkylurea derivatives; alkylaminophenol derivatives; melamine and guanamine; and dicyandiamide is particularly preferably used.

In the rust inhibitor of the present invention, the amount of the latent curing agent can be appropriately changed according to the equivalent weight of the epoxy resin used and the curing conditions.
It is preferable to add 1 to 20 parts by weight to 00 parts by weight. If the amount exceeds 20 parts by weight, the coating film becomes hard and brittle, and cracks may be generated by impact or strain, which may cause rust. On the other hand, if the amount is less than 1 part by weight, the adhesion between the coating film and the substrate is weak, and the rust-preventive property may be significantly reduced, which is not preferable. In addition, the above-mentioned imidazole derivative, N, N '
-Dialkyl urea derivatives, alkylaminophenol derivatives and the like can also be used as curing accelerators.

As described above, the rust preventive composition of the present invention comprises predetermined oxy resin, defoamer, plasticizer, reactive diluent and latent diluent as essential components. By adjusting the composition to the above predetermined range, excellent rust prevention, defoaming properties and adhesion to the substrate, for example,
Rust does not occur even after 400 hours of durability in the salt spray test.
A coating film having a shear strength of 2 MPa or more can be formed.

Further, in the rust preventive composition of the present invention,
If necessary, a powder polymer filler composed of an acrylate can be blended in addition to the above-mentioned essential components, whereby the oil surface adhesion can be further improved and the precuring property can be imparted. Examples of the powder polymer filler include (a) polymer resin particles using one or more of alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, and stearyl methacrylate; and methyl acrylate, butyl acrylate, and alkyl glycol (meth) acrylate. , (B) core-shell type polymer resin particles made of the above-mentioned polymer, and (c) polymer resin particles obtained by ion-crosslinking the surface of the polymer resin particles of (a) or (b). ) And (c) can be preferably used.

Further, if necessary, other fillers can be blended. For example, fused silica, crystalline silica, mica, alumina, calcium carbonate, calcium silicate, talc, barium sulfate, magnesium oxide, oxide Titanium and aluminum hydroxide can be blended. In addition,
These can be used alone or in any combination of two or more. The surface of these fillers may be treated with a silane coupling agent, a titanium coupling agent, a fatty acid, a surfactant, or the like.

It is also possible to add a rust preventive pigment such as zinc phosphate, aluminum phosphate, calcium phosphate and aluminum dihydrogen triphosphate or a rust preventive such as an amine salt of an organic acid. Properties can be further improved.

[0028]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. The composition and the coated product obtained in each example were evaluated by the following methods.

1) Evaluation of rust-preventive property: An ordinary steel plate specified in JIS G 3141, JIS G 3
302 galvanized steel sheet or JIS H 4000
Three types of test pieces were used in which a rust-preventive oil (Daphne Coat NR3 manufactured by Idemitsu Kosan Co., Ltd.) was applied to a specified aluminum alloy 5154. However, the ordinary steel plate and the galvanized steel plate had dimensions of 70 (W) × 150 (L) × 0.8 mm (t), and the aluminum alloy 5154 had a thickness of 2 mm. Table 1 Examples 1 to 13 and Comparative Example 1
The composition obtained in No. 8 was coated with a bar coater to a thickness of 100 μm. After gelling the methacrylate polymer by preheating, perform degreasing, phosphorus, acid coating treatment, electrodeposition coating,
Further, it was dried at 170 ° C. for 30 minutes. The test pieces treated as described above were subjected to a salt water spray test in accordance with JIS K 5400 to withstand 400 hours, and visually evaluated for the occurrence of rust on the coating boundary and the coating film surface.

2) Adhesion evaluation 2 g of rust preventive oil (Dafney coat NR3, manufactured by Idemitsu Kosan Co., Ltd.)
Using the test piece coated with m ² , the composition of each example was applied with a bar coater to a thickness of 0.5 mm, treated in the same process as the rust prevention evaluation, and the shear strength was evaluated according to JIS K 6850. Was.

3) Evaluation of defoaming property The compositions of each example were mixed with a lab stirrer at 1000 rpm for 3 minutes, applied to a test piece with a bar coater to a thickness of 100 μm, and the state of bubbles on the surface of the wet film after 1 hour had passed. When,
The degree of armpit after hardening treatment in the same process as in the above evaluation of rust prevention was visually evaluated.

(Examples 1 to 13) Epikote 828 (trade name, Yuka Shell Epoxy Co., Ltd.) as a liquid epoxy resin, and a copolymer A of vinyl and acrylic (trade name: Floren) as a defoaming agent AC-326F, Kyoeisha Chemical Co., Ltd.), vinyl copolymer B (trade name: Dispalon 1950, Kusumoto Kasei Co., Ltd.), acrylic polymer C
(Trade name: Disparon OX710, Kusumoto Kasei Co., Ltd.) and silicone-based polymer D (trade name: Floren AO-3, Kyoeisha Chemical Co., Ltd.) were used alone or as a mixture.

As a latent curing agent, dicyandiamide is used. As a mixture of a plasticity and a reactive diluent, tricresyl phosphate manufactured by Daihachi Chemical Co., Ltd. as a plasticizer and n as a reactive diluent are used. -Butyl glycidyl ether in a ratio of 2: 8, and as a powder polymer composed of acrylate, a core-shell methacrylate polymer F-351 (trade name, manufactured by Nippon Zeon Co., Ltd.)
The filler used was surface-treated calcium carbonate.
The compositions of Examples 1 to 13 were prepared according to the formulation shown in Table 1. Using the compositions obtained in Examples 1 to 13, rust prevention, adhesion and defoaming properties were evaluated. Table 1 shows the evaluation results.

[0034]

[Table 1]

(Comparative Examples 1 to 8) n-dodecyl alcohol (Kanto Chemical Co., Ltd.) as an alcohol-based defoaming agent E
Was added, and the compositions of Comparative Examples 1 to 8 were prepared with the formulations shown in Table 2, and the obtained compositions were applied and evaluated in the same manner as in the examples. Table 2 shows the results.

[0036]

[Table 2]

From Tables 1 and 2, it can be seen that, compared with the coated article using the composition of the comparative example, the coated article using the composition of the example has all of the rustproofing property, defoaming property and adhesion. It turned out to be well balanced and the effect of the present invention could be confirmed.

[0038]

As described above, according to the present invention, since a specific epoxy resin, a defoaming agent and the like are blended, various steel plates and various aluminum alloy plates to which press oil or rust-preventive oil is adhered. The present invention can provide a rust preventive composition for application to an oil surface, which exhibits excellent rust prevention and high adhesion.

Claims (8)

[Claims] 1. A salt spray test containing an epoxy resin derived from bisphenol A and / or bisphenol F, a defoaming agent, a plasticizer, a reactive diluent, and a latent curing agent for the epoxy resin. A rust preventive composition for oil surface application, which does not generate rust after 400 hours of durability. 2. The adhesiveness to a steel plate to which oil has adhered is
The rust preventive composition for oily surface application according to claim 1, wherein the shear strength is 12 MPa or more. 3. The method according to claim 1, wherein the defoaming agent is at least one polymer selected from the group consisting of an acrylic polymer, a vinyl polymer and an acrylic-vinyl copolymer, or silicone. The rust preventive composition for oil surface application according to claim 1 or 2, wherein 4. The above-mentioned vinyl polymer is represented by the following general formula: CH ₂ ＣＲCR ₁ —OR ₂ (wherein R ₁ is a hydrogen atom or a methyl group, and R ₂ is —COOR
₃ or indicates -O-R _3, in this case, R ₃ is an alkyl group,
It represents an aryl group, a nitrile group or an oxyethylene group. 4. The rust preventive composition for oily surface application according to claim 3, having a structure represented by the formula: 5. The above acrylic polymer is represented by the following general formula: CH ₂ ＣＲCR ₄ —COOR ₅ (wherein R ₄ represents a hydrogen atom as a methyl group, and R ₅ represents an alkyl group or an aryl group. The rust preventive composition for oily surface application according to claim 3 or 4, having a structure represented by the formula: 6. The acrylic-vinyl copolymer according to claim 1,
It is a copolymer of the vinyl polymer according to claim 4 and the acrylic polymer according to claim 5, wherein the oil polymer is coated on an oil surface according to any one of claims 3 to 5. Rust inhibitor composition. 7. A liquid epoxy resin (100 parts by weight), the defoamer (0.1 to 10 parts by weight), the plasticizer and the reactive diluent (10 to 150 parts by weight), The rust preventive composition for oil surface application according to any one of claims 1 to 6, further comprising 1 to 20 parts by weight of a water-soluble curing agent. 8. The method according to any one of claims 1 to 7, wherein the composition can be applied to an unrusted oil-treated steel sheet, an unrusted oily aluminum alloy sheet or an oil-plated steel sheet. Rust inhibitor composition for oil surface application.