JPS607667B2 - Radiation curable coating composition - Google Patents

Description

[Detailed description of the invention] The present invention relates to radiation curable coating compositions.

Recently, as a type of non-polluting paint, research has been actively conducted on so-called radiation-curable paints, which cure Q.8-ethylenically unsaturated bond-containing compositions by applying energy from ultraviolet rays, electron beams, gamma rays, etc. It is being said. By using this method, a strong coating film can be obtained in a short time with little or no use of organic solvents used in ordinary paints, and its advantages are immeasurable. but,
When this paint is applied to metal, particularly iron, it generally has a drawback of extremely poor adhesion.

Therefore, various improvements have been attempted. One method was to pre-surface-treat the iron material using phosphoric acid, zinc phosphate, zinc chromate, etc.

This surface treatment certainly improves the adhesion of the coating, but
All the methods were equally labor-intensive and inefficient.
Particularly, zinc phosphate treatment requires overflowing, so a bathtub is required, and there is a drawback that there is a large economic loss when treating large-capacity iron materials on an industrial scale. On the other hand, attempts have also been made to improve adhesion by changing the composition of the paint itself. For this purpose, a method has generally been adopted in which a large amount of carboxyl groups and hydroxyl groups are introduced into the composition. However, this method also has its own limitations; for example, when a large number of carboxyl groups and hydroxyl groups are introduced, the physical properties of the coating film, especially water resistance, green resistance, salt water immersion resistance, salt water spray, etc., become extremely poor, resulting in rust, rust, etc. This was not a desirable method from the viewpoint of corrosion prevention and protection of iron materials because the coating film was prone to blistering. On the other hand, solvent-based paints in which tannic acid is added to linseed oil-based resins or magnetic oils in order to improve corrosion resistance have long been known (British Patent Nos. 826,564 and 826,566).

However, the performance of the resin itself of these paints (for example, water resistance, hardness, etc.) was poor, so the anticorrosion properties were not sufficient. Furthermore, an initial treatment agent characterized by comprising a catalyst for starting the formation of a chelate compound of tannic acid and iron atoms as a rust preventive agent, and a crosslinking agent is also known (Japanese Patent Publication No. 35495/1983).

However, since the above-mentioned treatment agent alone does not show sufficient performance, the surface must be further coated with an anticorrosive paint or the like. The present invention aims to improve the drawbacks of the prior art as described above, and aims to provide a coating composition that can improve adhesion to iron cable materials without deteriorating the physical properties of the coating film. It is something.

That is, the present invention provides: (i) a resin in which at least one carboxyl group and a Q.8-ethylenically unsaturated bond are present in the molecule, or a combination of this and a Q.8-ethylenically unsaturated monomer; or a mixture of {o} carboxyl group and Q.3 in the molecule
- A monomer or oligomer containing at least one ethylenically unsaturated bond, or the same.

・At least one kind selected from a mixture with a P-ethylenically unsaturated monomer and/or a Q-8-ethylenically unsaturated bond-containing resin and having an acid value of 40 to 200 and a Q-8-ethylenically unsaturated bond Ingredients: 50 to 9 percent by weight of the box, [B - Uniform mixed solution consisting of 30 to 7 percent by weight of tannic acid and 70 to 30 percent by weight of water...
. . 50 to 2 percent by weight, and 'C) optionally a UV sensitizer.

A component with an acid value of 40 to 200 and containing a Q.6-ethylenically unsaturated bond as component (1) used in the present invention refers to a component containing at least a carboxyl group and a Q08-ethylenically unsaturated bond in the 'i' molecule. One or more resins, such as acrylic resins, modified epoxy resins, etc., or together with these.

・Mixture with 3-ethylenically unsaturated monomer or 'o}
Monomers or oligomers containing at least one carboxyl group and Q.8-ethylenically unsaturated bond in the molecule, such as acrylic acid; methacrylic acid; acrylic acid 2-
Reaction products of hydroxyethyl etc. and succinic anhydride or phthalic anhydride; Reaction products of glycidyl methacrylate and succinic acid or adipic acid, or these monomers or oligomers and ethylenically unsaturated monomers and/or.

- It is a mixture with 8-ethylenically unsaturated bond-containing resin. Examples of the Q/B-ethylenically unsaturated monomers include butyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, and methacrylate. butoxycetyl acid, jetylaminoethyl methacrylate, jetylene glycol diacrylate, trimethylolpropane triacrylate,
Examples include styrene, vinyl acetate, and acrylonitrile. The type of resin or compound mentioned above has properties that should be determined freely from the viewpoint of the purpose of use, required coating performance, and coating method, but in any case, it enhances the chelate formation effect by tannic acid. The acid value is 4.
It needs to be 0-200, particularly preferably 60-180.

If the acid value is less than 40, tannic acid will not sufficiently form a chelate with the base iron surface, and miscibility with water will also become difficult. On the other hand, if it exceeds 200, chelate bonds are easily formed, but the corrosion resistance of the coating becomes extremely poor.

The composition of the present invention contains as essential ingredients tannic acid, which causes a chelation reaction with the base iron surface, and water to promote the reaction.

Although tannic acid is soluble in water to some extent, it is generally difficult to dissolve in the above-mentioned components, so it is necessary to prepare a homogeneous mixed aqueous solution of tannic acid in advance. In the present invention, 30 to 7 weight percent of tasonic acid and 70 to 70 weight percent of water are used.
A uniformly mixed solution of 3% by weight is used.

If the amount of tannic acid is less than the above, more water than necessary will be used in the composition of the present invention, which will reduce the solubility of the Q.8-ethylene unsaturated bond-containing component containing a carboxyl group, and will also cause problems in coating. It requires very long setting time after installation. Furthermore, since the purpose of water is to promote the chelation reaction of tannic acid, it is not preferable to use more than necessary. On the other hand, if the amount of tannic acid exceeds the above ratio, it becomes difficult to dissolve tannic acid in water, and it becomes difficult to form a chelate sufficiently after coating.

The tannic acid aqueous solution 'B) is mixed with the Q.8-ethylenically unsaturated bond-containing component containing a carboxyl group and having an acid value of 40 to 200 to form the composition of the present invention.

In the present invention, acid value 40 to 40 containing carboxyl group
200 Q・8-Ethylenic unsaturated bond-containing component 50~
A ratio of 50 to 2 weight percent, preferably 30 to 1 weight percent of the homogeneous mixed solution of tannic acid and water is required for 9 mother weight percent, preferably 70 to 9 low weight percent.

If the uniform mixed solution of tannic acid and water exceeds 5% by weight, there will be excess tannic acid that does not react with the base steel surface, and the curing of the paint will be extremely slow. On the other hand, if the amount is less than 2% by weight, the desired chelation with the steel surface will not be achieved sufficiently, and the anticorrosion properties of the coating will deteriorate significantly.

It goes without saying that extender pigments such as calcium carbonate, talc, and precipitated barium sulfate; and coloring pigments such as titanium oxide, red iron oxide, and yellow lead can be used in the composition of the present invention, if necessary.

It is also free to use additives such as antifoaming agents and leveling agents. The composition of the present invention thus prepared and formulated can be applied to ferrous materials such as blasted steel plates, polished steel plates, dull steel plates, polished mild steel plates, or rusted steel plates using an applicator, bar coater, roll coater, flow coater, hand spray, etc. be done.

There is no particular limit to the coating film thickness, but 10 to 20 microns is usually sufficient. The coating is then exposed to energy radiation from electron beams or ultraviolet radiation, either immediately or after a suitable setting time.

As a result, a chelation reaction with the base iron surface and a curing reaction of the coating film occur in parallel, resulting in a coating film that has a faint blackish-purple color and has excellent adhesion. When the composition of the present invention is cured with the electron beam, it is sufficiently cured as it is, but when it is cured with ultraviolet rays, the ultraviolet sensitizer is added in a proportion of 0.05 to 3. % by weight must be added and cured.

The ultraviolet sensitizers include penzophenone, benzoin,
Benzoin methyl nal, benzoin isopropyl ether, benzyl, etc. are used. The coating film thus obtained can sufficiently perform anti-corrosion and protection functions as it is, but can be overcoated to provide even more durability.

Conventionally known solvent-diluted alkyd resin, epoxy resin, polyester resin paints, etc. are used as the top coat, but in particular, radiation-curable compositions are used as the top coat to create a cured coating using energy rays as described above. If this is done, a pollution-free coating system that uses no or almost no ordinary organic solvents will be completed. As mentioned above, the present invention utilizes Q-8-ethylenically unsaturated bonds to form a coating film by radiation in a short time, and reacts tannic acid with the base iron surface using carboxyl groups and water to form a chelate bond. This invention relates to a pollution-free paint that utilizes an extremely rational reaction system for chemical reaction, and is extremely useful as an anticorrosive paint composition, especially as an undercoat paint composition.

The details of the present invention will be explained below with reference to Examples.

Note that "parts" or "%" are expressed in "parts by weight" or "% by weight." Example 1 95 parts of epoxy resin [Epicote #828; trade name manufactured by Shell Kagaku ■], 36 parts of acrylic acid, 5 parts of triethylamine, and 0.2 parts of hydroquinone were mixed and heated to 120 to 130 qo while blowing air. A time-keeping acrylated epoxy resin was obtained.

After the temperature was brought to 110 qo, 25 g of succinic anhydride was added and the reaction continued for an additional 2 hours at 110 qo. As a result, a resin was obtained in which about half of the secondary hydroxyl groups generated by the reaction between the epoxy resin and acrylic acid were esterified with succinic anhydride.

The formation of the resin was confirmed by infrared absorption spectrum.
This was done by detecting the disappearance of absorption based on acid anhydrides in 0 Hada-1 and 1830 Hada-1.

After cooling, 34 parts of diethylene glycol diacrylate,
10 parts of 2-hydroxyethyl methacrylate was added to obtain a resin composition (component) having an acid value of 70.

Meanwhile, 10 parts of tannic acid and 10 parts of water were mixed to make 60q0
The mixture was uniformly dissolved to obtain component 'B}. After dissolving 2% penzoin isopropyl ether in the same manner as described above, it was mixed with Bi and then coated with a bar coater on a European steel plate that had been polished with No. 24 water-resistant abrasive paper. About 2 minutes. After leaving it for a while, the shoes W
Ultraviolet rays from a high-pressure mercury lamp were irradiated from a height of 20 skin to about 1 sand. The resulting coating was hard and smooth, with a faint blackish-purple color due to the reaction between tannic acid and the iron base.

The performance of the coating film is shown in the comparative test results table. Example 2 50 parts of succinic anhydride, 0 parts of 2-hydroxyethyl acrylate, 1 part of triethylbenzylammonium chloride
Ikaribe, Hydroki/N0. $ Department, 110-120pm
The mixture was heated for 4 hours to produce an ester of succinic anhydride and 2-hydroxyethyl acrylate.

To this were added 200 parts of 2-hydroxyethyl acrylate, 20 parts of styrene, and 17 parts of 1,6-hexanediol diacrylate to obtain a resin composition with an acid value of 170. To this, 32 parts of talc was added and uniformly brazed to obtain a composition. Separately, 198 parts of water were added to 297 parts of tannic acid and dissolved uniformly at 60:00 to obtain component [B-].

After mixing the component sail and (B), it was coated with a bar coater on a mild steel plate polished with #24 waterproof abrasive paper. After being left for about 10 seconds, it was irradiated with Mrad electron beam energy from a 500 KeV electron beam accelerator. The resulting coating film was thin due to the reaction between the tannic acid and the iron base, and had a smooth black-purple appearance.

The performance of the coating film is shown in the comparative test results table. After applying a conventional ultraviolet curable paint mainly composed of acrylated epoxy resin to this coating film, it was irradiated with ultraviolet rays from a Uta W high-pressure mercury lamp from a height of 20 skin for about 1 hour.

As a result, a highly hard coating film with excellent adhesion to the undercoat coating film could be obtained. It was found that this coating film could withstand the salt water fog test described below for more than 20 hours. Example 3 After mixing epoxy resin [Epicote #834; trade name manufactured by Shell Kagaku ■] 125 Gibu, 36 Hakato acrylic acid, 5 parts triethylamine, and 0.2 parts hydroquinone, the mixture was heated at 120 to 130 qo while blowing air. An acrylated epoxy resin was prepared by keeping it for a long time.

140 parts of this resin, 10 parts of 2-hydroxyethyl methacrylate, 226 parts of butoxyethyl methacrylate, and 144 parts of acrylic acid were added to obtain a resin composition (components) having an acid value of 60. On the other hand, 94 parts of tannic acid and 94 parts of water were mixed and uniformly dissolved at 60°C to obtain component [B'. After adding 2% of penzoin isopropyl ether to the component air and uniformly dissolving it, the component base was added and coated using a bar coater on a European steel plate polished with #24 water-resistant abrasive paper. After leaving it for about 2 minutes, apply ultraviolet rays from the arc W high pressure mercury lamp to a height of 2.
It was irradiated for about 7 seconds from 0 arc. The resulting paint film had a pale blackish-purple color, which appears to be due to a chelate reaction between the tannic acid and the base iron, and was extremely tough. The coating performance is shown in the comparative test results table. Example 4 120 parts of methyl methacrylate, 3 parts of butyl acrylate, 6 parts of 2-hydroxyethyl methacrylate, 9 parts of acrylic acid, and 6 parts of azobisisobutyronitrile were uniformly mixed and heated under reflux at the boiling point. was added dropwise over 2 hours into 300 parts of methyl lysobutyl ketone.

Thereafter, the mixture was kept under reflux for another 6 hours to synthesize an acrylic resin. Next, 60 parts of glycidyl methacrylate and 0.3 parts of hydroquinone were added and reacted at 120 to 130°C for 3 hours. This reaction results in a structure in which the carboxyl groups in the acrylic resin are partially bonded to the glycidyl groups of glycidyl methacrylate. The obtained resin composition was mixed with methanol 2
00 anchor to isolate the resin. to the isolated resin,
116 parts of diacrylic acid, 75 parts of hexanediol, and 10 parts of butoxycetyl methacrylate were added and uniformly dissolved to obtain a resin composition with a shark value of 80. Thereafter, 54 parts of calcium carbonate was added and kneaded, and 1 part of penzoinisopropyl ether was further added and dissolved to obtain a component base. On the other hand, 64 parts of tannic acid and 43 parts of water were mixed, maintained at 60 oo, and uniformly dissolved to obtain component [B].

After mixing the components (1) and 'B}, coating was performed on a degreased dull steel plate using a roll coater. After leaving it for about 3 minutes, ultraviolet rays from an arc W high-pressure mercury lamp were irradiated from a height of 20 skin to about 29 sand. The resulting paint film was pale, black-purple in color, and appeared to be caused by chelation between tannic acid and the base iron surface.
The paint film was flexible. The coating performance is shown in the comparative test results table. Example 5 Succinic anhydride and 2-hydroxyethyl acrylate were reacted according to Example 2.

To 270 parts of the reactant, 5 parts of 2-hydroxyethyl acrylate, 47 parts of styrene, and 100 parts of 1,6-hexanediol diacrylate were added to form a resin composition with an acid value of 120.
[Ingredients bad]] was obtained. On the other hand, 56 parts of tannic acid and 84 parts of water were mixed and uniformly dissolved at 6 ml to obtain component [B'.

After mixing the above components ① and [B', #24 with a bar coater.
Painted on a steel plate polished with water-resistant abrasive paper. After leaving the present sand for about one hour, it was irradiated with mother Mrad electron beam energy from a 50 plate eV electron beam accelerator. The resulting coating film had a smooth appearance with a pale black-purple color due to the reaction of the base iron surface. The performance of the coating film is shown in the comparative test results table. Comparative Examples 1 to 2 Only the components of the compositions of Examples 1 and 2 were coated under the same conditions and irradiated with ultraviolet rays and electron beams.

The results are also shown in the comparative test table. Comparative test results Surface adhesion) Cut 100 pieces of cellophane into 1 minute squares.
The students filled out the squares and recorded the percentage of the number of squares remaining.

Claims (1)

[Claims] 1 (A) (a) Carboxyl group and α/β- in the molecule
A resin containing at least one ethylenically unsaturated bond, or a mixture of this and an α/β-ethylenically unsaturated monomer, or (b) a carboxyl group and an α/β-ethylenically unsaturated monomer in the molecule. Both unsaturated bonds are at least 1
monomers or oligomers present, or together with α/β-ethylenically unsaturated monomers and/or α/β-ethylenically unsaturated monomers
- at least one selected from the group consisting of a mixture with an ethylenically unsaturated bond-containing resin having an acid value of 40 to 200 and α/β
Ethylenically unsaturated bond-containing component...50 to 98% by weight, (B) a homogeneous mixed solution consisting of 30 to 70% by weight of tannic acid and 70 to 30% by weight of water...
...50 to 2% by weight, and (C) an ultraviolet ray sensitizer if necessary. 2 Component (A) 70-90% by weight and component (B)
30 to 10 percent by weight.