JP2958672B2 - Painted metal sheet by electron beam curing method and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a coated metal plate having a multilayer coating film, having excellent ion-resistance of not less than 500 Mohm · cm ² , excellent corrosion resistance, high hardness, stain resistance and anti-glare. It concerns the manufacturing method.

[0002]

2. Description of the Related Art As a method for producing a coated metal plate having high hardness and excellent stain resistance, the present inventors have disclosed a method disclosed in Japanese Patent Publication No. 4-453.
The technology disclosed in Japanese Patent Publication No. 42 has already been put to practical use.

However, the coated metal sheet according to the present invention has a sufficient corrosion resistance in a severe corrosive environment, for example, in a place facing a coast or in a tunnel where chlorides (NaCl, CaCl ₂ ) are sprayed to prevent freezing of roads. It turns out that it is not.

[0004]

DISCLOSURE OF THE INVENTION The present invention relates to a coated metal sheet having high hardness, excellent stain resistance, excellent anti-glare properties, and sufficient corrosion resistance (for example, 5 years or more) even in a severe corrosive environment, and its production. It provides a method.

[0005]

The gist of the present invention is as follows. The lowermost layer contains two or more (meth) acryloyl groups in one molecule and has a (meth) acryloyl group equivalent of 40.
It has a solid or near-solid heat-cured coating consisting of a composition containing 0 or less oligopolyester (meth) acrylate as an essential component, and has two (meth) acryloyl groups in one molecule on it. It has one or more coating films comprising a composition containing an oligopolyester (meth) acrylate having an equivalent weight of 400 or less and having a (meth) acryloyl group equivalent of 400 or less, and curing all these layers by electron beam irradiation. A coated metal sheet having excellent corrosion resistance, characterized in that the coating has an ion permeation resistance of 500 M ohm · cm ² or more, and a method for producing the same.

[0006] 2. The above-mentioned uppermost layer coating film further contains two or more (meth) acryloyl groups in one molecule and an oligopolyester (meth) acrylate having a (meth) acryloyl group equivalent of 400 or less and two or more in one molecule. A composition containing a polyhydric alcohol (meth) acrylate containing a (meth) acryloyl group and having a (meth) acryloyl group equivalent of 150 or less as an essential component is applied, and all of these layers are simultaneously cured by electron beam irradiation. A coated metal sheet having excellent corrosion resistance and a method for producing the same.

[0007] 3. In the above 1 and 2, the Cr content is 1
A coated metal plate having excellent corrosion resistance using a stainless steel plate of 3% or more as a base metal plate and a method for producing the same. It is in.

[0008]

The present inventors have studied various methods for solving the above-mentioned problems, and as a result, firstly, the coating film has a multilayer structure, and secondly, these layers are cured by electron beam irradiation to reduce the ion permeation resistance. be a 500M ohm · cm ² or more, further have found the fact that it is possible to obtain a coated metal plate having excellent corrosion resistance by using a stainless steel plate of Cr content is 13% or more as the third as the base metal plate .

First, regarding the first coating film having a multi-layer structure, even if the first coating film has the same film thickness, for example, when coating 40 μm, 30 μm is applied rather than 40 μm at a time. After coating 5 μm, it was found that coating 5 μm further improved the corrosion resistance remarkably.

The reason for this is that if there is a defect (pinhole) in the coating film on one layer, corrosive substances (ions, gases, etc.)
On the other hand, it is considered that in the multilayer structure, corrosion of the metal plate is drastically reduced because each layer compensates for a defect (pinhole). The multilayer structure means at least three layers, preferably four layers or more.

Next, the ion permeation resistance of the second coating film is set to 50
With respect to 0M ohm · cm ² or more, generally water vapor, ions, there can be no one that does not at all transmitted through the gas and the like, ion permeation resistance 500M Ohm · cm ² or more, more preferably 1.5G ohm · cm It has been found that the corrosion resistance is improved probably because it becomes difficult to penetrate suddenly at ² or more.

In order to obtain the above resistance value, it is conceivable to select an appropriate resin structure and increase the film thickness.

As for the former, a polar functional group is contained in the resin structure.
For example, -COOH, -OH, -NH _Two, Others as much as possible
It is better not to be present.

Although it is impossible to eliminate 100% in the synthesis of the resin, the oligopolyester (meth) used in the present invention is not used.
In the acrylate and polyhydric alcohol (meth) acrylate, those in which 85% or more, preferably 95% or more, of the polar functional groups contained in the molecule of the monomer of the synthesis raw material are reacted are considered to be the gist of the present invention. It is.

The above resistance value can be obtained by applying two or more layers based on the above concept and a coating thickness of about 30 to 40 μm or more. However, even in this case, as described above, a multilayer coating is used as a coating. Is good.

In this case, the thickness of the lowermost layer is at least 20 μm or more, and the thickness of the coating film to be applied thereon is at least 1 μm or more, preferably 3 μm or more.
More than two layers, preferably two or more layers are good. However, the total thickness is desirably 70 μm or less.

The reason is that the electron beam cured resin coating film used in the present invention is limited as described above.
When the coating film is highly cured and the internal stress of the coating film is large and the coating film is used for a long period of time, there is a possibility that cracks or the like may occur, and it is economical.

As described above, the effect of the present invention can be obtained for the first time by superposition of the three requirements. The present invention will be described in more detail.

The oligopolyester acrylate used in the present invention refers to a product obtained by using a polyester skeleton in the main chain and subjecting (meth) acrylic acid to an esterification reaction. In view of the necessity of having a crosslinked network structure, one molecule contains two or more (meth) acryloyls, more preferably three or more.

Since the crosslink density must be sufficiently high, the (meth) acryloyl group equivalent is desirably 400 or less.

This component will be described in more detail. Oligo (meth) acrylate having a polyester skeleton in the main chain is composed of a polyhydric alcohol and a polycarboxylic acid, and has a hydroxyl group at the end of the polyester, and is reacted with (meth) acrylic acid or a derivative thereof. A (meth) acryloyl group is introduced. Here, the raw material for forming the polyester skeleton will be further described.

That is, as the dihydric alcohol, alkylene glycol types such as ethylene glycol, propylene glycol, chloropropylene glycol, butanediol (1,3- or 1,4- or 2,3-),
-Alicyclic glycol type such as methylpentanediol, 2,2-diethylpropanediol, pentamethylene glycol, 1,6-hexanediol, heptamethylene glycol, octamethylene glycol, nonamethylene glycol, neopentyl glycol, hexamethylenediol, etc. 1,4-cyclohexanediol, cyclohexane-1,4-dimethanol, hydrogenated bisphenol A, etc. As polyalkylene glycol type, diethylene glycol, triethylene glycol, polyethylene glycol, dipropylene glycol, polypropylene glycol, polytetramethylene glycol , Polybutadiene diol, etc., and as an aromatic glycol type, 2,2'-bis (4-hydroxyphenyl) propane (also Enol A), bis (4-hydroxyphenyl) methane (also called bisphenol F), 4,
Glycols obtained by adding an alkylene oxide (ethylene oxide, propylene oxide, butylene oxide, etc.) to a phenol such as 4'-dihydroxyphenyl, hydroquinone, resorcin, and the like are included.

As the tri- to tetrahydric alcohols, alkanetriol types such as glycerin, trimethylolmethane, trimethylolethane, trimethylolpropane,
1,2,6-hexanetriol, 1,2,3-butanetriol, 1,2,3-pentanetriol, 2-methyl-2,3,4-butanetriol, 2-ethyl-
2,3,4-butanetriol, 2-methyl-1,2,2
Examples of alkanetetraols such as 3-butanetriol, 2-ethyl-1,2,3-butanetriol, 2,3,4-hexanetriol, pentamethyleneglycol, erythritol, pentaerythritol, toilet, 1,2,3 4-pentane tetrol, 2,3
4,5-hexanetetrol, 2,5-dimethyl-2,
3,4,5-hexanetetrol, 1,2,3,5-pentanetetrol, 3-hexene-1,2,5,6-tetrol, 3-hexyne-1,2,5,6-tetrol and the like Erythritol and pentaerythritol as ether-containing aliphatic tetraols, such as triols obtained by adding alkylene oxides (such as ethylene oxide, propylene oxide, and butylene oxide) to glycerin and trimethylolpropane as ether-containing aliphatic triols; And the like, and an aromatic triol such as a triol obtained by adding an alkylene oxide to pyrogallol.

As the carboxylic acid, a chain or branched 2
Oxalic acid, malonic acid, succinic acid,
Glutaric acid, itaconic acid, maleic acid, fumaric acid, adipic acid, sebacic acid, dodecanoic acid, methylene glutaric acid, methyl maleic acid, methyl succinic acid, dodecenyl succinic acid, and other aliphatic dicarboxylic acids such as tetrahydrophthalic acid and hexahydrophthalic acid 1,6-methyltetrahydrophthalic acid, 6-methylhexahydrophthalic acid, endomethylenetetrahydrophthalic acid, endoisopropylidenetetrahydrophthalic acid, 1,4,5,6,7,7-
Hexachloro-endo-5-norbornene-2,3-dicarboxylic acid (also known as hetic acid), 1,4,5,6,7,7
-Hexabromo-endo-5-norbornene-2,3-
Examples of the dicarboxylic acid, cyclohexane, 1,4-dicarboxylic acid and the like, and examples of the aromatic dicarboxylic acid include phthalic acid, isophthalic acid, terephthalic acid, tetrachlorophthalic acid, tetrabromophthalic acid, and anhydrides thereof.

Some specific examples of the polyester oligomers having two (meth) acryloyl groups of these are di (meth) acrylates of polyester diols of maleic acid and ethylene glycol,
Polyester di (meth) acrylate of maleic acid and diethylene glycol, polyesterdiol di (meth) acrylate of adipic acid and diethylene glycol, di (meth) acrylate of polyesterdiol of tetrahydrophthalic acid and diethylene glycol, tetrahydrophthalic acid and propylene glycol Di (meth) acrylates of polyester diols with tetrahydrophthalic acid and butanediol (1,3- or 1,4
Di (meth) acrylate of polyester diol with-), di (meth) acrylate of polyester diol with tetrahydrophthalic acid and 1,6-hexanediol,
Di (meth) acrylate of polyester diol with tetrahydrophthalic acid and neopentyl glycol, di (meth) acrylate of polyester diol with tetrahydrophthalic acid and 1,4-cyclohexanediol, di (meth) acrylate of polyester diol with phthalic acid and diethylene glycol (Meth) acrylate, and di (meth) acrylate of polyester diol of phthalic acid and neopentyl glycol.

Among these polyester oligomers,
Tetrahydrophthalic acid or adipic acid with 3 to 3 carbon atoms
A polyester oligomer having a di (meth) acrylate structure of a polyester diol with six alkylene glycols and having a number average molecular weight of 350 to 800 and a number average molecular weight of 180 to 400 per (meth) acryloyl group is an object of the present invention. Is particularly preferable.

Specific examples of some of the polyester oligomers having two or more (meth) acryloyl groups include tetra (meth) acrylate of a polyester polyol of adipic acid and pentaerythritol;
Penta (meth) acrylate, hexa (meth) acrylate, tetramethacrylate of polyester polyol of tetrahydrophthalic acid and pentaerythritol,
Penta (meth) acrylate, hexa (meth) acrylate, tetra (meth) acrylate, penta (meth) acrylate, hexa (meth) acrylate of polyester polyol of phthalic acid and pentaerythritol,
Tetra (meth) acrylate, penta (meth) acrylate, hexa (meth) acrylate of polyester polyol with maleic acid and pentaerythritol, tetra (meth) acrylate, penta (meth) of polyester polyol with adipic acid and trimethylolpropane
Acrylate, hexa (meth) acrylate, tetra (meth) acrylate, penta (meth) acrylate, hexa (meth) acrylate of polyester polyol of tetrahydrophthalic acid and trimethylolpropane,
Tetra (meth) acrylate and penta (meth) of polyester polyol of tetrahydrophthalic acid and glycerin
Acrylate, hexa (meth) acrylate and the like.

Among these polyester oligomers,
Polyester polyol of adipic acid or tetrahydrophthalic acid with trimethylolpropane or pentaerythritol, having a structure of tetra (meth) acrylate, penta (meth) acrylate or hexa (meth) acrylate, and having a number average molecular weight of 550 to 2000, (meth) Number average molecular weight of 100 to 35 per aryloyl group
A polyester oligomer of 0 is preferred for the purposes of the present invention.

Next, the polyhydric alcohol (meth) according to the present invention
Acrylate refers to one in which (meth) acrylic acid is reacted with a hydroxyl group at the terminal of a polyhydric alcohol to introduce a (meth) acryloyl group, and is used in combination with oligo (meth) acrylate to obtain a very high crosslinking density. It plays a role.

For this purpose, one molecule contains two or more (meth) acryloyl groups, and the (meth) acryloyl group equivalent is preferably 150 or less, more preferably about 130 or less.

In this case, a mixture of the above-mentioned polyhydric alcohol (meth) acrylate may be used. The polyhydric alcohol mentioned here means the following.

That is, as the dihydric alcohol, alkylene glycol types such as ethylene glycol, propylene glycol, chloropropylene glycol, butanediol (1,3- or 1,4- or 2,3-),
-Alicyclic glycol type such as methylpentanediol, 2,2-diethylpropanediol, pentamethylene glycol, 1,6-hexanediol, heptamethylene glycol, octamethylene glycol, nonamethylene glycol, neopentyl glycol, hexamethylenediol, etc. 1,4-cyclohexanediol, cyclohexane-1,4-dimethanol, hydrogenated bisphenol A, etc. As polyalkylene glycol type, diethylene glycol, triethylene glycol, polyethylene glycol, dipropylene glycol, polypropylene glycol, polytetramethylene glycol , Polybutadiene diol, etc., and as an aromatic glycol type, 2,2'-bis (4-hydroxyphenyl) propane (also Enol A), bis (4-hydroxyphenyl) methane (also called bisphenol F), 4,
Glycols obtained by adding an alkylene oxide (ethylene oxide, propylene oxide, butylene oxide, etc.) to a phenol such as 4'-dihydroxyphenyl, hydroquinone, resorcin, and the like are included.

As the trihydric or higher alcohol, alkanetriol type glycerin, trimethylolmethane, trimethylolethane, trimethylolpropane,
1,2,6-hexanetriol, 1,2,3-butanetriol, 1,2,3-pentanetriol, 2-methyl-2,3,4-butanetriol, 2-ethyl-
2,3,4-butanetriol, 2-methyl-1,2,2
Examples of alkanetetraols such as 3-butanetriol, 2-ethyl-1,2,3-butanetriol, 2,3,4-hexanetriol, pentamethyleneglycol, erythritol, pentaerythritol, dipentaerythritol, toilet, 1, 2,3,4-pentane tetrol, 2,3,4,5-hexane tetrol,
2,5-dimethyl-2,3,4,5-hexanetetrol, 1,2,3,5-pentanetetrol, 3-hexene-1,2,5,6-tetrol, 3-hexyne-1,
Fatty ethers containing ether groups, such as triols obtained by adding alkylene oxides (ethylene oxide, propylene oxide, butylene oxide, etc.) to glycerin, trimethylolpropane, etc. as aliphatic triols containing ether groups such as 2,5,6-tetrol Examples of the aromatic tetraol include a tetraol obtained by adding an alkylene oxide to erythritol and pentaerythritol, and examples of the aromatic triol include a triol obtained by adding an alkylene oxide to pyrogallol.

Of these, those having a (meth) acryloyl group equivalent of 120 or less are particularly preferred.

As described above, the resin component of the composition constituting the present invention has been described. In addition, pigments, solvents, polymers and the like can be added as required.

Inorganic coloring pigments include red iron oxide, yellow iron oxide, chromium vermillion, chromium oxide, carbon black and the like, and organic coloring pigments include quinacridone, isoindolinone, indanthrene blue, phthalocyanine blue, phthalocyanine green and the like. Is raised.

Other examples include titanium white, calcium carbonate, barium sulfate, alumina, silica and the like. It is also added to the overprinting varnish as needed.

Examples of the solvent include xylene, butyl acetate, cyclohexanone, methyl cellosolve, ethyl cellosolve, morpholine, and olefin solvents.

As the polymer, there are cases where the polymer is used to improve the coating property.
Urethane, epoxy or the like is used. In this case, if the amount is too large, the performance is reduced, so an appropriate amount is added.

In the present invention, the lowermost coating film is heat-cured to a solid state or a state close to a solid state because it must not be completely cured in order to apply one or more layers thereon.

This film thickness is at least 15 μm or more, preferably at least 25 μm. The number of layers to be overcoated is one or more, preferably two or more, more preferably three or more,
Each film thickness is desirably 2 μm or more and 10 μm or less.

The reason for this is that if it is too thin, the effect of compensating for coating film defects (pinholes) is diminished, and if it is too thick, the curability after electron beam curing increases, so that the shrinkage stress also increases and the coating film cracks.
This is because delamination or the like easily occurs.

Although a coating film having high hardness and stain resistance can be obtained with the above composition, antiglare properties are required depending on the use.

In this case, various measures can be considered, but it has been found that a method of giving smooth geometrical irregularities to the outermost surface layer of the coating film is preferable.

In other words, although the anti-glare effect can be obtained with the conventional extender, the stain resistance is lowered.

The method of providing smooth geometrical irregularities on the surface is such that the addition of glass or resin beads serves the purpose of the present invention. Specific examples include the following.

As the glass beads, soda lime glass or low alkali glass having a particle size of 2 μm to 70 μm is preferable depending on the required unevenness.

[0048] Soda-lime glass is slightly traced by alkali or water, but may be eluted over a long period of time, and low alkali glass is preferred because it reduces ion permeation resistance.

Examples of the resin beads include relatively hard beads such as melamine, styrene acryl, Teflon, and polyacrylonitrile. From the viewpoint of hardness, crosslinked acrylic resin beads are preferable, and depending on the required irregularities. Those having a particle size of 2 μm to 100 μm are selected.

In addition, beads such as nylon and urethane may be used depending on applications where high hardness (8H) is not required. If corrosion resistance is emphasized, resin beads are more preferable.

Here, the ion permeation resistance of the coating film will be described. Focusing on the fact that corrosion is an electrochemical process,
Electrochemical AC impedance measurement in an aqueous solution is performed, and the ion permeation resistance value of the coating film can be obtained from the analysis of the result.

This value corresponds to the corrosive ion species (C
_{^{l -, SO 4 2-, NO}} 3 -, the penetration into the interior of such), which the coating is quantitatively indicating the degree of how may suppressed how, as the measuring method Sho 60- 100751,
62-229056 and Japanese Patent Application No. 63-126242.

As the apparatus, a coating film deterioration degree diagnostic sensor (R) commercially available from Nippon Steel Technos (Sagamihara City, Kanagawa Prefecture) is used.
If the ST Model 3) is used, the above value can be easily obtained by performing the area correction.

The reason why the ion permeation resistance value of the coating film is specified to be 500 M ohm · cm ² or more in the present invention is as follows.

In various coating systems, coated metal sheets having different ion permeation resistance values of coating films were prepared by changing the film thickness and the number of times of recoating, and the time required for rust spot formation in the composite corrosion test of these samples was determined. The measurement resulted in the results shown in FIG.

In this composite test, 0.01 N sulfuric acid,
Spraying a mixed aqueous solution of 0.01N nitric acid and 3% calcium chloride at 40 degrees Celsius for 3 hours, then drying at 60 degrees Celsius for 3 hours, and further maintaining the humidity at 95 degrees Celsius at 60 degrees Celsius for 6 hours Was repeated.

A commercially available SUS41 is used as the base metal plate.
0 was used. As is evident from FIG. 1, the time required for the rusting to suddenly increase from around the ion permeation resistance value of the coating film of the present invention exceeding 500 Mohm · cm ² .
It begins to saturate above 5 Gohm · cm ² .

This tendency is the same for both the coating composition (x) according to claim 1 and the coating composition (〇) according to claim 3, but the latter has the same ion permeation resistance value of the coating. Even if it has a slightly longer life.

In any case, when the coating system of the present invention is applied to stainless steel, in order to secure sufficient corrosion resistance, 5
It is necessary to make it equal to or more than 00 M ohm · cm ^2, and if possible, it is preferable to be 1.5 G ohm · cm ² or more.

Next, the third reason why a stainless steel sheet having a Cr content of 13% or more is applied to the metal sheet used in the present invention will be described.

Commercially available SUS410 (13% Cr), S
US430 (18% Cr), YUS180 (19Cr-
0.4Cu-0.4Nb-low C-low N) and YUS
220 (22Cr-0.8Mo-0.4Nb-0.5C
Using u) as a base material, applying a coating film having an ion permeation resistance value of 500 M ohm · cm ² in the coating system according to claim 1 and conducting a composite corrosion test in the same manner as described above to measure the time until the occurrence of spot rust. did.

As a result, spot rust occurred in SUS410 after 1400 hours, whereas SUS430 produced 540 points of rust.
0 hours, 7900 hours for YUS180, YUS220
The corrosion resistance was greatly improved as the contents of chromium and molybdenum in the base material increased, such as 24,000 hours (SUS is a symbol specified in Japanese Industrial Standards, YUS is a symbol of Nippon Steel Corporation) Trademark attached to stainless steel products).

Until now, as a painted stainless steel having a life of 10 years or more in a tunnel where severe corrosive environment occurs,
From the experience so far, it was 500 in the above-mentioned combined corrosion test.
It has been considered that 0 hours or more is desirable, and therefore, it is desirable that the base stainless steel contains 18% or more Cr. Here, it goes without saying that by combining a coating system having a high coating film ion permeation resistance value and a base material with an increased amount of corrosion-resistant alloying elements, it is possible to design and manufacture a further corrosion-resistant coated stainless steel. .

Based on the first and second structural requirements described above and using a zinc-plated steel sheet as the metal plate,
Generally, high corrosion resistance according to the present invention, for example, in a severely corrosive environment, in a tunnel in which chlorides (NaCl, CaCl ₂ ) are sprayed back and forth in places facing the coast or in order to prevent freezing of roads, etc., for at least 5 years. Can be

If a stainless steel plate having a Cr content of 13% or more is used as the base metal plate, more complete high corrosion resistance can be obtained.

Next, a method for producing the coated steel sheet of the present invention will be described.

In the coated metal plate of the present invention, the original plate is a stainless steel plate as described above, but this may be a cut plate shape or a coil shape.

These may be degreased in the steel plate manufacturing process and further subjected to a chemical conversion treatment with chromic acid, phosphoric acid, a silane coupling agent or the like, or may be used in the pretreatment step in the painting step. Is used.

It is preferable to use a primer between the original plate and the composition of the present invention. As the composition of the primer, any material such as epoxy, modified epoxy, epoxy acryl, polyester, and epoxy polyester may be used as long as it has good adhesion to a stainless steel plate.

The coating method is an ordinary method such as a roll coater, and the curing method may be any method such as heat, electron beam, and ultraviolet light. The coating film thickness is about 1 to 10 μm, preferably about 2 to 8 μm.

As a method of applying the ground coat according to the present invention, a coating method such as a roll coat and a curtain flow coat is used. The thickness is as described above.

Here, the thermal curing of the ground coat will be described. It has also been found that the resin system of the invention used for this can be thermoset to a state where it can be overcoated without a polymerization catalyst.

The sheet temperature during thermosetting is 120 ° C. to 200
A temperature of about 20 ° C. and a time of about 3 minutes are suitable for this purpose.

As a method of further applying a layer on the ground coat cured in such a state that it can be applied again, a roll coat method used for coating, a gravure offset method used for printing, a silk screen method, or the like is used. When two or more layers are applied, the same method may be repeated or a combination with another method may be used. The ground coat and the overcoat layer may be colored and patterned as needed.

The electron beam irradiation method in the manufacturing method of the present invention will be described.

Examples of the irradiation device include a scanning system, a curtain beam system, a broad beam system, and the like. The required acceleration voltage is selected according to the coating film thickness. The electron beam irradiation atmosphere is replaced with an inert gas or the like.

In the present invention, a protective film such as polyvinyl chloride, polyethylene, or polypropylene may be laminated on the coating film.

Next, the present invention will be described specifically with reference to examples.

[0079]

【Example】

[0080]

Example 1 First, the following 3 paints were applied to the base material.
Prepared the kind.

Paint A (Grand Coat): 20 parts of titanium oxide I was added to 100 parts of an oligomer (acryloyl group equivalent: about 155) having a condensation molar ratio of tetrahydrophthalic acid, trimethylolpropane, and acrylic acid of 1: 2: 4. Painted.

Paint B (first layer on A): A paint was prepared by adding 100 parts of titanium oxide to 100 parts of the oligomer used in A.

Coating C-1 (second layer on A): A composition was prepared by adding trimethylolpropane trimethacrylate (acryloyl group equivalent: about 155) to 100 parts of the oligomer used in A.

Next, as an example of the present invention, a ferritic stainless steel sheet (19Cr-0.4Cu-0.4Nb) coated with a thermosetting epoxy primer (3 μm) was prepared.
A was applied using a curtain flow coater (manufactured by Iwata Coating Machine) so that the dry film thickness was 35 μm. This is the plate temperature 140
Heated under the condition of ° C. to make a soft solid.

On this soft solid coating film, B is applied by a gravure offset printing machine so as to have a dry film thickness of 5 μm, and C-1 is further applied by a gravure offset printing machine so as to have a dry film thickness of 5 μm. Applied.

Thereafter, the three layers were simultaneously cured by electron beam irradiation. The curing conditions were a current of 160 mA / 1.2 m, an irradiation dose of 9 Mrad, and an oxygen concentration at the time of irradiation of 150 ppm (test No. 1).

On the other hand, as a comparative example, A was 45
μm and 60 μm were applied, and a coated plate was produced under the same conditions as in the present invention without applying B and C-1 (Test N
O. 2 and 3).

Further, as a comparative example, the base metal plate was coated with A in a dry film thickness of 45 μm using a hot-dip galvanized steel plate instead of a stainless steel plate, and the present invention was applied without coating B and C-1. A coated plate was produced under the same conditions as in Test No.
4).

For these coated plates, JIS K540
0 based pencil hardness test, magic ink (red,
Blue, black), curry, mustard, colored pencil, ink, etc., 24 hours later, evaluation of the ease of removal with gauze dipped in ethanol, so-called stain resistance, 5% hydrochloric acid, sulfuric acid, acetic acid, caustic soda and Changes in coating properties after immersion in methyl ethyl ketone and acetone for 240 hours, evaluation of so-called chemical resistance, evaluation of corrosion resistance by salt spray test, and Nitetsu Technos Co., Ltd.
Each test evaluation, such as measurement of the ion permeation resistance of the coating film using ST Model 3, was performed.

Table 1 shows the results of these evaluations. As is clear from the table, the coated plate according to the present invention is extremely excellent in corrosion resistance, and also excellent in pencil hardness, stain resistance and chemical resistance.

[0091]

EXAMPLE 2 Next, the following 4 paints were applied to the base material.
Prepared the kind.

Paint A (Grand Coat): A of Example 1
Same as.

Paint B (first layer on A): A of Example 1
Same as.

Paint C-2 (second layer on A): 100 parts of titanium oxide was added to 100 parts of the oligomer used in A to form a paint.

Paint D-1 (third layer on A): A composition was prepared by adding trimethylolpropane trimethacrylate (acryloyl group equivalent: about 155) to 100 parts of the oligomer used in A.

Therefore, a ferrite stainless steel sheet coated with a thermosetting epoxy primer (3 μm) was coated with A
Was applied with a curtain flow coater (manufactured by Iwata Coating Machine) so as to have a dry film thickness of 30 μm. The plate temperature is 140 ° C
And heated to a soft solid state.

On this, B was applied by a gravure offset printing machine so as to have a dry film thickness of 5 μm, C was further applied by a gravure offset printing machine so that the dry film thickness was 5 μm, and then D was further applied. Coating was performed with a gravure offset printing machine so that the dry film thickness was 5 μm.

Thereafter, the four layers were simultaneously cured by electron beam irradiation. The curing conditions were a current of 160 mA / 1.2 m, an irradiation dose of 12 Mrad, and an oxygen concentration at the time of irradiation of 150 ppm. The same evaluation test as in Example 1 was performed using this coated plate (Test No. 5).

As shown in Table 2, the evaluation results showed that the corrosion resistance of the sheet of the present invention was more excellent than that of the sheet of Example 1, and extremely good performance was obtained.

[0100]

Example 3 In Example 2, a crosslinked poly (methyl methacrylate) (average particle size: 20 parts) was applied to 100 parts of the composition of the coating material D.
μm) A composition containing 5% of beads was replaced with D (D-
The coating was made under the same conditions as in Example 2 for the other paints, and a performance test was performed (Test No. 6).

As shown in Table 2, the performance evaluation shows extremely good results as in Example 2.

The gloss value was measured in Examples 2 and 3 for reference. As a result, it was 85 in Example 2 and 65 in Example 3.

[0103]

[Table 1]

[0104]

[Table 2]

[0105]

The coated metal sheet manufactured by the present invention has high hardness, high contamination resistance and high corrosion resistance, so that it is sprayed on sea salt particles from the coast and on road freeze prevention. Can be sufficiently used for building materials in coastal areas exposed to extremely severe corrosive environments due to chloride ions coming from snow-melting salts, tunnel interior panels, etc., reducing the need for repairs and replacement. Is big.

[Brief description of the drawings]

FIG. 1 is a diagram showing the relationship between the ion permeation resistance of a coating film and the time until occurrence of rust.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI B32B 15/08 B32B 15/08 Q C08F 299/04 C08F 299/04 C09D 4/00 C09D 4/00 5/00 5/00 5 / 08 5/08 167/06 167/06 (72) Inventor Nagaharu Ueno 20-1 Shintomi, Futtsu-shi Nippon Steel Corporation Technology Development Division (72) Inventor Hiroshi Kihira 20-1 Shintomi, Futtsu-shi Made in New Japan (72) Inventor Katsuya Kusakari 4013 Nakatsu, Aikawa-cho, Aiko-gun, Kanagawa Prefecture Inside Nihon Erio Co., Ltd. (72) Inventor Toshihiro Kano 4013 Nakatsu, Aikawa-cho, Aiko-gun, Kanagawa Pref. 72) Inventor Masato Horikiri 450 Aotomachi, Midori-ku, Yokohama-shi The Intecc Co., Ltd. (72) Inventor Tomoaki Mukaiyama 450 Aotomachi, Midori-ku, Yokohama-shi The Intecc Co., Ltd. (56) References Special JP-A-6-47341 (JP, A) JP-A-1-75508 (JP, A) JP-A-5-317800 (JP, A) JP-A-4-270772 (JP, A) JP-A-60-40169 (JP , A) JP-A-2-242863 (JP, A) JP-B-4-32708 (JP, B2) (58) Fields investigated (Int. Cl. ⁶ , DB name) B05D 5 / 00,1 / 36 B05D 7/14 B05D 7/24 301 B05D 7/24 302 B32B 15/08 C08F 299/04 C09D 4 / 00,5 / 00,5 / 08 C09D 167/06

Claims (6)

(57) [Claims] 1. A solid material comprising, as a lowermost layer, a composition containing two or more (meth) acryloyl groups in one molecule and an oligopolyester (meth) acrylate having a (meth) acryloyl group equivalent of 400 or less as an essential component. Alternatively, it has a thermosetting coating film in a state close to a solid, on which two or more (meth) acryloyl groups are contained in one molecule, and (meth)
It has one or more coating films composed of a composition containing an oligopolyester (meth) acrylate having an acryloyl group equivalent of 400 or less as an essential component, and the ion transmission resistance of all coating films is 50 or more.
A coated metal sheet having excellent corrosion resistance, characterized by being at least 0 M ohm · cm ² . 2. A coating comprising, as a lowermost layer, a composition comprising an oligopolyester (meth) acrylate containing at least two (meth) acryloyl groups in one molecule and having a (meth) acryloyl group equivalent of 400 or less as an essential component. The film is heat-cured to a solid or near-solid state, and contains two or more (meth) acryloyl groups in one molecule, and (meth)
One or more coatings composed of a composition containing an oligopolyester (meth) acrylate having an acryloyl group equivalent of 400 or less as an essential component are applied, and all these layers are cured by electron beam irradiation to reduce the ion permeation resistance of the coating. A method for producing a coated metal sheet having excellent corrosion resistance, wherein the metal sheet has a thickness of 500 M ohm · cm ² or more. 3. The uppermost coating film according to claim 1, further comprising:
A molecule containing two or more (meth) acryloyl groups in the molecule and having a (meth) acryloyl group equivalent of 400 or less and an oligopolyester (meth) acrylate having two or more (meth) acryloyl groups in one molecule, and A coated metal plate having excellent corrosion resistance, characterized by being coated with a composition containing a polyhydric alcohol (meth) acrylate having a (meth) acryloyl group equivalent of 150 or less as an essential component. 4. The method according to claim 2, further comprising:
A molecule containing two or more (meth) acryloyl groups in the molecule and having a (meth) acryloyl group equivalent of 400 or less and an oligopolyester (meth) acrylate having two or more (meth) acryloyl groups in one molecule, and A method for producing a coated metal sheet having excellent corrosion resistance, comprising applying a composition containing a polyhydric alcohol (meth) acrylate having a (meth) acryloyl group equivalent of 150 or less as an essential component. 5. The coated metal plate having excellent corrosion resistance according to claim 1, wherein a stainless steel plate containing 13% or more of Cr is used as a base metal plate. 6. A claim was a metal plate of stainless steel containing 13% or more Cr base material 2 or 4 method for manufacturing a coated metal sheet excellent in corrosion resistance according.