JPS6063264A - Temporary rust preventing composition - Google Patents

Abstract

PURPOSE:The titled composition, obtained by incorporating a specific unsaturated radically reactive resin, etc. with calcium zinc cyanamide in a specific proportion, capable of removing the film thereof with an alkali, and having improved rust preventing property and water resistance. CONSTITUTION:A temporary rust preventing composition obtained by incorporating (A) 95-99.9wt%, preferably 98-99.5wt% unsaturated radically reactive resin, curable with active energy radiation, e.g. X rays or alpha rays, and having 10- 60 acid value and if necessary an unsaturated radically reactive monomer, e.g. styrene or vinyl acetate, with (B) 0.1-5wt%, preferably 0.5-2wt% calcium zinc cyanamide. EFFECT:Improved storage stability.

Description

DETAILED DESCRIPTION OF THE INVENTION More specifically, the present invention relates to a temporary rust-preventing composition that can be removed with an alkaline aqueous solution and can form a coating film with excellent rust-prevention properties.

Traditionally, as a temporary protection method for metal substrates, it has been known to apply a coating to the surface and scrape off the coating before or after processing to prevent rust, contamination, and damage to the substrate. ing.

That is, the method that has been commonly used in the past is (1) applying various oils to a base material, and dissolving and cleaning with an organic solvent when removing the oil.

(,2) A resin composition having a large amount of carboxyl groups in the molecule is applied to the substrate, and when removed, it is dissolved and washed with an alkaline aqueous solution.0) A resin composition having a large amount of amino groups in the molecule. The method was to apply a substance and, when removing it, dissolve and clean it with an acidic aqueous solution.

However, in method (1), the physical strength and blocking resistance of the protective coating film are not sufficient, and furthermore, it is necessary to use an organic solvent for removal, which is problematic from the viewpoint of pollution (toxicity) and safety. It was also not favorable in terms of resource conservation.

In addition, method Q) uses a composition that has a large amount of carboxyl groups in its molecules, so the adhesion and flexibility of the coating film are poor, and the viscosity during coating increases, resulting in high non-volatility. The workability of the coating process was also unsatisfactory. In addition, due to the chemical structure of the resin, although it can be removed by dissolving in an alkaline aqueous solution, there are problems with the rust prevention ability, chemical resistance, and water resistance of the coating film while protecting the base material. The drawback was that the material was susceptible to deterioration.

Furthermore, in the case of (3), although the resin composition has the feature that it can be coated with a relatively low viscosity and can be temporarily dissolved and removed with an acidic aqueous solution, the physical strength of the coating film during impurity retention of the base material, In terms of blocking resistance, chemical resistance, water resistance, etc., these were not necessarily sufficient.

The inventors of the present invention conducted extensive research to improve the drawbacks of the prior art as described above, and as a result, they were able to create a composition with excellent storage stability by adding a small amount of a specific pigment. . Therefore, the composition has the feature that it can be removed with an alkaline aqueous solution and can form a coating film with excellent rust prevention properties, water resistance, and the like.

That is, the present invention provides (a) an acid value of 10, which is curable by active energy rays;
-t, o unsaturated radically reactive resin and optionally unsaturated radically reactive monomer 9S to 99.9% by weight
and (b) Calcium diamide zinc... θ/~5-layered view-
The present invention relates to a temporary rust preventive composition which can be removed from the film by using an alkaline aqueous solution.

The "unsaturated radically reactive resin" used in the present invention is a polymerizable polymer or oligomer having an unsaturated bond group in the resin and having an acid value of 10 to θ. Such resins include commercially available unsaturated epoxy resins, unsaturated urethane resins, unsaturated polynisdel resins, etc. for ultraviolet curing or radiation curing, and these can be used as they are.

In addition, in the above, if the acid value of the unsaturated radical-reactive resin is less than that of IO, it is difficult to remove the film with an alkaline aqueous solution, while if the acid value exceeds 60, the rust prevention properties of the coating film will be poor. In either case, it was not preferable because it lowered the value.

In the present invention, "active energy rays" include ultraviolet rays, X-rays, α-rays, electron beams, etc. from high-pressure mercury lamps, low-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, and xenon lamps.

Next, in the composition of the present invention, a commonly used unsaturated radically reactive monomer may be mixed if necessary.

The monomer is added as appropriate depending on the coating workability of the composition, the performance required of the coating film, etc. More specifically, the monomers include monomers having at least one unsaturated group in the molecule, such as (a) (meth)acryloyl group-containing monomers, and (b) aromatic vinyl group-containing monomers. It is an aliphatic vinyl group-containing monomer.

Examples of (a) include hydroxyl group-containing monomers such as co-hydroxyethyl (meth)acrylate and co-hydroxyzorobyl (meth)acrylate; methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate, and tetrahydrofurfuryl acrylate. Needel compounds of the above-mentioned hydroxyl group-containing monomers and alkyl alcohols or uw-like alkyl alcohols; methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, neopentyl glycol di(meth) acrylic
), /-4 hexanediol di(meth)acrylate,
Ester compounds of (meth)acrylic acid and alkino alcohols such as (meth)acrylate; mono(2-hydroxyethyl acrylate) acid phosphate, mono(2-hydroxyethyl methacrylate) acid phosphate, di( Examples include phosphoric acid esters of acrylic acid or methacrylic acid containing a hydroxyl group such as -monohydroxyethyl acrylate) acid phosphate.

Furthermore, examples of the above (b) include styrene, vinyltoluene, and the like.

Further, as the above rt, for example, vinyl acetate, vinyl chloride
Examples include IJden.

These can be used singly or as a mixture of more than one.

On the other hand, the "calcium cyanamide zinc" used in the present invention is usually commercially available as a pigment, and can be used as it is.

Next, in the composition of the present invention, the above-mentioned (a) component and (b)
) Calcium cyanamide zinc as component 2, the former 9
The latter is mixed at a ratio of 5 to 99.9% by weight, preferably 9g to 795% by weight, and the latter θ/~5% by weight, preferably 05 to 2% by weight.

In the above range, the amount of calcium cyanamide zinc is 0.7
If the amount is not expressed as a percentage by weight, the antirust effect of the coating film will be significantly reduced. On the other hand, if the amount exceeds 5% by weight, the viscosity of the composition becomes high and the coating workability is deteriorated, and the storage stability of the composition is significantly deteriorated. Therefore, either case is not preferable.

In addition to the above-mentioned components, the composition of the present invention may further contain commonly used dyes, extender pigments, additives, small amounts of organic solvents, etc., if necessary.

In particular, when the composition of the present invention is used as an ultraviolet curable composition, known photosensitizers such as benzoin, benzoin methyl ether, benzoin isopropyl ether, benzyl, benzophenone, anthraquinone, naphthoquinone, chloranthraquinone, The composition of the present invention contains seven or a mixture of two or more of tetramethylthiuram disulfide, diphenyl disulfide, 21λ-jetoxyacetophenone, penzoyl perogylide, azobisisobutyronitrile, co-2-azobispropane, etc. Approximately θθ with respect to the object! ; Add and mix -5M amount.

The composition of the present invention can be obtained by simply mixing and kneading each component or the proportions explained above.

Therefore, the composition of the present invention obtained in this way,
It is applied to the preparation by methods such as brush coating, ironing, spray coating, dip coating, shower coating, roll coating, etc., and then hardened by irradiation with active energy rays.

The obtained coated steel material is further easily removed by an alkaline aqueous solution when necessary, but until then it is protected by a coating film obtained from the composition of the present invention which has excellent rust prevention properties, moisture resistance, etc.

The details of the present invention will be explained below with reference to Examples. however,[
"part" or "chi" is expressed as "1 part by weight" or "wt%".

Example/ Unsaturated epoxy resin [Manufactured by Thinlayer Kasei Co., Ltd. Part name: UV-2
23: Acid value 3θ] gs part, tetrahydrofurfuryl acrylate/part, and calcium cyanamide zinc/part were mixed in a ball mill for 16 hours, and then 3 parts of benzoin isopropyl ether was added to obtain the composition of the present invention. .

Next, the composition was applied to a polished mild steel plate (θg×riθ×
/3θ-) to a film thickness of /5-20μ, and then
Ultraviolet rays were irradiated for 3 seconds at an irradiation distance of 1 scrn using a high-pressure mercury lamp of OW/.

The performance of the obtained coating film is summarized in Table 1.

Example: 5 parts of unsaturated urethane resin (manufactured by Inu Nippon Ink Kagaku Kogyo Co., Ltd. Part name: Unidic/7-za72: acid value core), 2'A of no hydroxypropyl acrylate! i part and calcilamcyamamide zinc θS part were mixed, and the following Example/
A coated sawn board was obtained in the same manner as above.

The performance of the obtained coating film is summarized in Table 1.

Example 3 Unsaturated epoxy resin (manufactured by Nippon Upica Co., Ltd., product name: Upica Coat EX900, 3 parts of nitric acid value, 3 parts of λ-hydroxypropyl acrylate, and 3 parts of calcium cyanamide zinc) were mixed, and the following procedure was carried out in the same manner as in Example. A coated steel plate was obtained.

The performance of the obtained coating film is summarized in Table 1.

Comparative Example/Unsaturated epoxy resin [manufactured by Nippon Upica Co., Ltd., part name Uvica Coat AC33θ/: acid value 90] gO part, 15 parts euhydroxyprobyl acrylate, and calcium cyanamide zinc S part were mixed, and the following was the same as in Example/ A coated steel plate was obtained.

The performance of the obtained coating film is summarized in Table 1.

COMPARATIVE EXAMPLE A coated steel sheet was obtained by mixing unsaturated epoxy resin (1 g O part same as in Example 1), 70 parts of tetrahydrofurfuryl acrylate and 76 parts of calcium cyanamide zinc, and in the same manner as in Example 7.

The performance of the obtained coating film is summarized in Table 1.

Comparative Example 3 Unsaturated epoxy resin (same as Example 1) gS part 12 parts of tetrahydrofurfuryl acrylate and 3 parts of zinc phosphate were mixed and a coated steel sheet was obtained in the same manner as in Example.

The performance of the obtained coating film is summarized in Table 1.

Comparative example: unsaturated epoxy resin [manufactured by Dainippon Ink and Chemicals Co., Ltd., part name: Unidic v-sso, :t: acid value 3] 0 parts, co-hydroxypropyl acrylate 75 parts, and calcium cyanamide sub-S part A coated steel plate was obtained in the same manner as in Example 1.

The performance of the obtained coating film is summarized in Table 1-C.

Comparative Example S 0 parts of unsaturated urethane resin (same as in Example A), 1993 parts of non-hydroxypropyl acrylate, and 0.05 parts of calcium cyanamide zinc were mixed, and a coated steel sheet was obtained in the same manner as in Example 1. The performance of the obtained coating film is summarized in Table 1.

Comparative Example 6 Unsaturated urethane resin (same as Example A) go part and 2-
0 part of hydroxypropyl acrylate was mixed and the same procedure as in Example 1 was carried out to obtain a coated steel plate.

The performance of the obtained coating film is summarized in Table 1.

Note/) /wn width gopan stitch adhesion is shown by the number of remaining stitches after peeling off with seven strips.

Note) According to JIS-, ff4tθ0.

Note 3) DuPont impact test, ///2 inches x Sθθ
j / '% Removal state of coating film after 30 minutes of immersion in NaOH aqueous solution at 5θ~60°C ○Complete removal × Remaining coating film Note 7) 1 container containing each composition in a constant temperature bath at 30°C
After leaving it for 20 hours, observe the condition.

○ No abnormality, △ Slightly thickening, × Gelling From the above comparative test results, it is clear that the composition of the present invention has excellent storage stability, and the coating film obtained from it has excellent rust prevention, moisture resistance, and film removal. In contrast, compositions outside the scope of the present invention either have poor storage stability, or have extremely poor rust prevention, moisture resistance, or film removability of the coating film. I wanted it to be practical.

Claims (1)

[Claims] 9!
~999% by weight (b) Calcium cyanamide zinc: Temporary rust preventive composition that can be removed by an alkaline aqueous solution, consisting of 07 to 5% by weight.