JPS6040169A - Manufacture of coated metallic plate and coating composition - Google Patents

Abstract

PURPOSE:To obtain a coated metallic plate having excellent chemical resistance, hardness, etc., by applying a coating composition containing a specific (meth) acrylate monomer, a silica-based extender pigment and a polymer to a metallic plate substrate, and curing the composition with electron radiation. CONSTITUTION:A metallic plate substrate is coated with a coating composition composed essentially of (A) an oligo(meth)acrylate containing >=2 (meth)acryloyl groups in one molecule and having a (meth)acryloyl group equivalent of >=2 (meth)acryloyl group in one molecule and having a (meth)acryloyl group equivalent of <=150, (C) a silica-based extender pigment and (D) a polymer having a molecular weight of >=5,000, and the applied coating composition is cured with electron radiation in an inert gas having an oxygen concentration of <=1% to obtain the objective coated metallic plate.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for producing a coated metal plate and a coating composition in which the coating film is cured by electron beams.

(Prior Art) Generally, paints are soluble in solvents, and the solvents are scattered at room temperature or by heating.

A crosslinking/curing reaction is caused by heating, ultraviolet rays, infrared rays, etc. to insolubilize and form a cured coating film.

However, with these methods, it is difficult to obtain a product that does not swell or change color when exposed to any organic solvent, and has sufficient stain resistance against magic ink, whiteboard markers, etc. be.

As seen in JP-A-49-32488, the inventors of the present application have already applied a paint consisting of an oligo(meth)acrylate system and a polyhydric alcohol (meth)acryloyl system to a metal plate, and cured it with an electron beam. By curing the coating film using this method, we succeeded in obtaining a coated metal plate with high hardness, solvent resistance, and excellent stain resistance.

However, it has been found that the above resin system has two problems when applied to actual industrial lines.

In other words, ■It is easy for dust to adhere after painting and before electron beam irradiation.
■Electron beam irradiation is performed in an inert gas, but due to slight fluctuations in the atmosphere, the painted surface may be patchy or uneven after curing.
There are two points that are likely to cause this: 91 When the surface appearance is particularly important, there are two points in production.

It turned out that this was a problem in terms of product value. I will discuss these two points in more detail.

Regarding item (1), it is clear that the resin system of JP-A-49-32488 has extremely high chargeability after coating with an industrial coating method, such as a curtain flow coater, and irradiating the coated plate with an electric wire. became. This chargeability was measured using a 5tatic honestmet manufactured by Shishido Shokai Co., Ltd.
r Type S-4104, which is measured using a constant voltage (here s KV)
is applied to the sample, and after the application is stopped, the attenuation of the electrostatic voltage on the sample is continuously measured to determine the time it takes for the electrostatic voltage to decrease by half (half-life). In this case, it can be determined that the longer the half-life, the more easily the substance is charged.

Here, measurements are made on the coated board after curing. In reality, it would be appropriate to measure on a painted board before curing, but 1
The present inventors have experimentally discovered that there is a correlation between the chargeability of a coated plate after curing and the amount of dust that adheres after painting until curing. That is, we have clarified an experimental fact that when the half-life mentioned earlier is set to 100 seconds or less, but 80 seconds or less, dust is less likely to adhere.

■Let's talk about the section.

Coating film curing by electron beam irradiation is usually carried out in an inert gas atmosphere, and the same applies to the manufacturing method for coated metal plates in the present invention.

A simple conceptual diagram is shown in Figure 1. That is, the conveyor 11
The uncured painted plate 2 runs in the direction of the arrow above ~1□2 (in the case of a coil, it will be low sea), and the inert gas supply pipe 4I
The material enters an inert gas atmosphere supplied from .about.4□ and is cured by an electron beam taken out from the electron beam irradiation window 5 at the bottom of the scan hole 76. In order to check the oxygen concentration, atmospheric gas is constantly sent to the analyzer from the gas sampling tube 3 for the oxygen analyzer. In this case, an inert gas control device as shown in FIG. 1 is provided under the irradiation window of the electron beam irradiation device, and an inert gas is supplied.
The purpose of this is to lower the oxygen concentration, but the practical problem in industrial production lines is that when the coated plate enters the inert gas control device, oxygen is brought in, and from a microscopic perspective, the oxygen concentration near the coated plate surface varies depending on the location. The concentration of oxygen in the atmosphere will vary depending on the situation, and will differ from the oxygen concentration in the atmosphere captured by an oxygen analyzer. Therefore, this is presumed to be the cause.

After curing, the product has patches and unevenness, and there are even cases where the gloss value is 80 in areas where the same coat is coated, and 40 in areas where it is dry.As a solution, inert gas exchange and low oxygen concentration Although it was found that it would be sufficient to make the inert gas uniform, it was technically difficult, and furthermore, from the viewpoint of operating costs, it was desirable to reduce the amount of inert gas used as much as possible.
This is an attempt to solve the problem from the paint aspect.

(Structure of the present invention) As a result of various studies, the inventors of the present invention have found that adding an extender pigment is effective in preventing patches and unevenness. Among extender pigments, those that are even slightly effective include silica, white carbon, diatomaceous earth, calcium carbonate, clay, asbestin, and Merck, among which silica is particularly effective. There are various types of silica, and there is one parameter that represents their characteristics, for example.

PH1 average particle diameter, bulk specific gravity (y/cc) - surface area (17?/f) and others, but for the purpose of the present invention, oil absorption (r/1001i') is the most influential. Found experimentally. That is, the oil absorption amount is 10
It has been found that if silica is added in an amount of 097'1oo9 or more, it is possible to prevent "uneven gloss" on the coated plate after curing.

Estimating the reason for this from an experimental perspective, the outermost layer of a board coated with a paint containing silica, which has an oil-absorbing amount, is harder to the touch than that without the addition of silica. ,
Is it relatively close to a solid state and physically difficult to adsorb and dissolve oxygen?

Alternatively, chemically, the addition of these silica-based extender pigments may prevent uneven luster after curing, which is difficult to adsorb and dissolve, or it may be due to other causes, but in any case, adding silica-based extender pigments We have experimentally discovered that adding it can prevent uneven shine.

1 Oligo (meta) which is another component in the present invention
It has also been discovered that when a silica-based extender pigment is added to acrylate and polyhydric alcohol (meth)acrylate, the half-life can be shortened even in the 0 term chargeability mentioned above. The reason why it becomes difficult for dirt and dust to adhere is that this half-life can be shortened, and the painted surface is harder (closer to a solid) than when silica-based extender pigments are not added. It is estimated from experimental facts that it is difficult for these substances to adhere.

As mentioned above, the silica-based extender pigment is one of the oligosaccharides of the present invention (
meth) acrylate, polyhydric alcohol (meth) acrylate, which prevents the adhesion of “dirt” and “stiffness”.
Furthermore, it completely prevents patches and unevenness during irradiation,
Naturally, depending on the amount added, it can also have a matting effect.

Next, we will discuss the effects of polymers with a molecular weight of 5,000 or more. This makes the effects of the silica-based extender pigment more pronounced in the present invention.

Furthermore, it improves the coating properties when coating with an industrial coating machine.

In this case, from the viewpoint of improving coating properties, the polymer is a homogeneous or nearly solid substance, and its viscosity must be 100,000 centipoise or more. Furthermore, considering other parameters, it is preferable that the resin has an elongation of 100 modulus or more, and a glass transition point of the resin is 40°C or lower, preferably 30°C or lower, although this is limited to solids. .

In the present invention, which uses a silica-based extender pigment as an essential component,
When a system without the addition of a polymer is coated with an industrial coating machine, the paintability of this system is poor due to the lack of viscosity, so the addition of a polymer is an essential condition.

Here, oligo(meth)acrylate will be explained in more detail. (Meta)acryloyl base and (Meta)
If the acryloyl group equivalent is 1 within the scope of the present invention, acrylic, epoxy, polyamide, silicone, urethane and other rings generally meet the performance of the present invention in combination with polyhydric alcohol (meth)acrylate; Considering this, polyester has the most preferable performance. The oligo(meth)acrylate used in the present invention has a polyester skeleton in the main chain, and has (
Refers to the product obtained by esterifying meth)acrylic acid.The product used in the present invention contains two or more (meth)acryloyl groups in one molecule due to the need to have a sufficient crosslinked network structure. More preferably, it contains three or more. Furthermore, since the crosslinking density must be sufficiently controlled, the (meth)acryloyl group equivalent is preferably 500 or less, more preferably 400 or less. In this case, two or more of these oligo(meth)acrylates may be used in combination as long as they satisfy the requirements of the present invention described above.

Let's talk about this ingredient in more detail. Oligo(meth)acrylate with a polyester skeleton in the main chain is composed of polyhydric alcohol and polycarboxylic acid, and the polyester has a hydroxyl group at the end, and is reacted with (meth)acrylic acid or a sheep derivative. (meth)acryloyl group is introduced. Here, we will further discuss the synthetic raw materials forming the polyester skeleton.

That is, as dihydric alcohols, alkylene glycol types include ethylene glycol, globylene glycol, and chloropropylene glycol.

Butanediol (1,3- or 1,4- or 2,3
-), 3-methylbentanediol, 2,2-diethylpropanediol, pentamethylene glycol, l, 6
-Hexanediol, heptamethylene glycol, octamethylene glycol, nonamethylene glycol, neopentyl glycol, hexamethylene diol, alicyclic glycol types, 1,4-cyclohexanediol, cyclohexane-1'7-1. 4-dimethazole, hydrogenated bisphenol A, etc., as polyalkylene glycol types; diethylene glycol, triethylene glycol, polyethylene glycol, siglobylene glycol, polypropylene glycol, polytetramethylene glycol, polybutadiene diol, etc., still as aromatic glycol types; -2,2'-bis(4-hydroxyphenylpropane) llJ name bisphenol A), bis(
4-Hydroxyphenyl)methane llJ name bisphenol 1? ), 4,4'-dihydroxyphenyl, hydroquinone, and glycols obtained by adding alkylene oxides (ethylene oxide, propylene oxide, butylene oxide, etc.) to phenols such as hydroquinone and resorcinnato.

Examples of tri- to tetrahydric alcohols include glycerin, trimethylolmethane, trimethylolethane, and trimethylolpropane as alkanetriol types. 1.2. '6
-hexandriol, 1,2.3-butanetriol, 1,2.3-pencuntriol, 2-methyl-2,
3,4-butanetriol, 2-methyl-2,3,4-
Butanetriol, 2-methyl-1゜2.3-butanetriol, 2-ethyl-1,2,3-butanetriol, 2-3", 4-hexanetriol, pentamethylene glycol, etc., erythritol , Pentaerythritol, Toilet+,
1,2,3.4 pentanetetrol, 2,3,4.5 hexanetetrol, 2,5-dimethyl-2,3,4,5
-Hexanediol+ 1.2.35-Pentanetetrol, 3-hexene-1,2,5°6-tetrol, 3-hexene-1,2,5,6-tetrol, etc. as an ether group-containing aliphatic triol.

Triols obtained by adding alkylene oxides (ethylene oxide, propylene oxide, butylene oxide, etc.) to glycerin, trimethylolpropane, etc., and ether group-containing aliphatic tetraols obtained by adding alkylene oxides to erythritol, pentaerythritol, etc. Examples of aromatic triols include triols obtained by adding alkylene oxide to pyrogallol.

Examples of carboxylic acids include chain or branched divalent carboxylic acids such as oxalic acid, malonic acid, and succinic acid.

Alicyclic dicarboxylic acids such as glutaric acid, itaconic acid, maleic acid, fumaric acid, adipic acid, sebacic acid, dodecanoic acid, methylene glutaric acid, methylmaleic acid, methylsuccinic acid, and dodecenylsuccinic acid, as well as tetrahydrophthalic acid and hexahydrophthalic acid. acid, 6-methyltetrahydrophthalic acid.

6-methylhexahydrophthalic acid, endomethylenetetrahydrophthalic acid, endoisopropylidenetetrahydrophthalic acid, 1.4,5,6,7.7-hexachloro-endo-5-norbornene-z, 3-dicarboxylic acid (
Also known as het acid) + 1.4, 5, 6. '7.7-hexapromoendo-5-norbornene-2,3-dicarboxylic acid, cyclohexane, 1,4-dicarboxylic acid, etc.
Examples of aromatic dicarboxylic acids include phthalic acid, isophthalic acid, terephthalic acid, tetrachlorophthalic acid, tetrabromophthalic acid, and anhydrides thereof.

Specific examples of polyester oligomers containing two (meth)acryloyl groups include di(meth)acrylate of polyester diol of maleic acid and ethylene glycol, and polyester of maleic acid and diethylene glycol. di(meth)acrylate.

Polyester diol di(meth)acrylate of adipic acid and diethylene glycol, di(meth)acrylate of polyester diol of tetrahydrophthalic acid and diethylene glycol, di(meth)acrylate of polyester diol of tetrahydrophthalic acid and propylene glycol
Acrylate.

Polyester diol (meth) of tetrahydrophthalic acid and butanediol (1,3- or +1,4-)
Acrylate, di(meth)acrylate of polyester diol of tetrahydrophthalic acid and 1,6-hexanediol, di(meth)acrylate of polyester diol of tetrahydrophthalic acid and neopentyl glycol, tetrahydrophthalic acid and 1,4-cyclohexane Examples include di(meth)acrylate of polyester diol with diol, di(meth)acrylate of polyester diol with phthalic acid and diethylene glycol, and di(meth)acrylate of polyester diol with phthalic acid and neopentyl glycol.

Among these polyester oligomers, it has a structure of polyester diol (meth)acrylate of tetrahydrophthalic acid or adipic acid and alkylene glycol or cycloalkylene glycol having 3 to 6 carbon atoms, and has a number average molecular weight: 350 to SOO. - (meta)
Number average molecular weight per acryloyl group 180-400
The polyester oligomers are particularly suitable for the purposes of the present invention.

Furthermore, specific examples of polyester oligomers having two or more (meth)acryloyl groups include tetra(meth)acrylate, penta(meth)acrylate, and hexanepolyester polyol of adipic acid and pentaerythritol. (meth)acrylate, tetramethacrylate of polyester polyol with tetrahydrontal acid and pentaerythyl
meth)acrylate, hexa(meth)acrylate, tetra(meth)acrylate of polyester polyol with phthalic acid and pentaerythritol, penta(meth)acrylate, hexa(meth)acrylate, tetra( meth)acrylate, penta(meth)acrylate, hexa(meth)acrylate, tetra(meth)acrylate of polyester polyol with adipic acid and trimethylolpropane, penta(meth)acrylate,
Hexa(meth)acrylate, tetra(meth)acrylate of polyester polyol of tetrahydrophthalic acid and trimethylolpropane, penta(meth)acrylate, hexa(meth)acrylate, tetra( of polyester polyol of tetrahydrophthalic acid and glycerin)
Examples include meth)acrylate, penta(meth)acrylate, and hexa(meth)acrylate.

Among these polyester oligomers, adipic acid or tetrahydrophthalic acid and trimethylolpropane,
Or polyester polyol with pentaerythritol has a structure of tetra(meth)acrylate, penta(meth)acrylate or hexa(meth)acrylate and has a number average molecular weight of 550 to 2000. Polyester oligomers having one (meth)acryloyl group and a number average molecular weight of 100 to 350 are suitable for the purposes of the present invention.

The polyhydric alcohol (meth)acrylate referred to in the present invention refers to one in which a (meth)acryloyl group is introduced by reacting the terminal hydroxyl group of a polyhydric alcohol with (meth)acrylic acid, and when combined with an oligo(meth)acrylate. This serves as a means to obtain an extremely high crosslinking density. For this purpose, one molecule should contain two or more (meth)acryloyl groups, and the (meth)acryloyl group equivalent should be 150 or less, more preferably about 130 or less. In this case,
A mixture of the aforementioned polyhydric alcohol (meth)acrylates may also be used. The polyhydric alcohol referred to here refers to the following.

That is, as dihydric alcohols, alkylene glycol types include ethylene glycol, propylene glycol, and chloropropylene glycol.

Butanediol (1,3- or 1,4- or 2,
3-)-3-methylbentanediol, 2,2-diethylpropanediol, pentamethylene glycol, 1.
6-hexanediol, heptamethylene glycol, octamethylene glycol, nonamethylene glycol, neopentyl glycol, hexamethylene diol, etc.
Alicyclic glycol types include 1,4-cyclohexanediol, cyclohexa7-L4-dimetatool, hydrogenated bisphenol A, etc. Polyalkylene glycol types include diethylene glycol and triethylene glycol.

Polyethylene glycol, diglopylene glycol, polypropylene glycol, polytetramethylene glycol, polybutadiene diol, etc. are still aromatic glycol types, such as 2,2'-bis(4-hydroxyphenylpropane) (also known as bisphenol A), bisphenol A, etc. (4-hydroxyphenyl)methane (also known as bisphenol F),
4. Orkylene oxide (
Examples include glycols obtained by adding ethylene oxide, propylene oxide, butylene oxide, etc.).

Examples of trihydric or higher alcohols include glycerin, trimethylolmethane, trimethylolethane, trimethylolpropane, and 1,2.6 alkantriol types.
-hexandriol 1,2.3-but-2-methyl-2.
3. , 4-butanetriol, 2-methyl-2,3,4
-butanetriol, 2-methyl-1,2,3-butanetriol, 2-ethyl-1,2,3-butanetriol, 2-3,4-hexanetriol, pentamethylene glycolnato, alkantetraol, Erythritol, bare p-erythritol, dipentaerythritol, toilette, 1,2,3.4 pentanetetrol, 2,3,4.5 hexantetrol, 2,5-dimethyl-2,3,4,5-hexantetrol Troll, 1.2
．． 3.5-Pentanetetrol, 3-hexene-1,2
', 5.6 tetrol, 3 hexyne-1,2,5,6-
Ether group-containing aliphatic triols such as tetrol, glycerin and trimethylolpropane, alkylene oxides (ethylene oxide, propylene oxide, etc.).

ether group-containing aliphatic tetraols such as tetraols obtained by adding alkylene oxide to erythritol, pentaerythritol, etc.
! ! Examples of aromatic triols include triols obtained by adding alkylene oxide to pyrogallol.

Of these, as a result, the (meth)acryloyl group equivalent is 1
Particularly preferred are those of 20 or less.

Furthermore, one important thing is that the addition of a polymer is an essential condition of the present invention, as mentioned above.

This results in decreased performance. In order to prevent this performance deterioration, oligo(meth)acrylates and polyhydric alcohols (
In the present invention, where it is essential to add a polymer, it is particularly preferred that the average (meth)acryloyl group equivalent is in the range of 100 to 200 in a system in which meth)acrylate is mixed. This is the point.

Here, we will discuss the blending ratio of oligo(meth)acrylate and polyhydric alcohol (meth)acrylate. Oligo (meth) acrylate/polyhydric alcohol (meth) acrylate A range of 1105 to 1/10 (weight (juice ratio)) is desirable. This is because oligo (meth) acrylate alone does not increase the crosslinking density sufficiently. However, polyhydric alcohol (meth)acrylate is added to improve the crosslinking density.

In order to meet the purpose of the present invention, the amount must be at least 0.5 to oligo(meth)acrylate 1. Here, the upper limit of polyalcohol (meth)acrylate is 10 to 1 for oligo(meth)acrylate, but if more than this is added and the coating film is cured,
Perhaps due to internal shrinkage stress, the number of cracks increases when the paint film cracks or gets scratched over time. Therefore, it is preferably 10 or less.

Furthermore, compared to the case of JP-A-49-3248'8, it is possible to increase the amount of polyhydric alcohol (meth)acrylate added by adding a polymer with a molecular weight of 5000 or more, which will be described later, thereby solving the above-mentioned trouble. This is because it can be prevented.

Next, I will talk about extender pigments. The materials that meet the purpose of the present invention have been mentioned above, but the most effective one is silica, which has an oil absorption of 100? /100 or more, more preferably l 50 f/LOOf. Regarding the amount, 1. silica is added in an amount of 0.5 part or more, preferably 1.0 part or more, per 100 parts of the total amount of oligo(meth)acrylate, polyhydric alcohol (meth)acrylate, and polymer referred to in the present invention. Then, the purpose of the present invention is met.

Specifically, the names are Fuji Davison Chemical's "Thyroid" series, Mizusawa Chemical's "Mizukasil"
series, Pamildon'' series, Tokuyama Soda's ``Relex Jillies 71.11) Kushiel'' series, ``Fine Seal'' series.

Examples include the "Carplex" series manufactured by Geotsugi Pharmaceutical and the "Aerosilpa" series manufactured by Nippon Aerosil. In the present invention, a mixture of two or more types of extender pigments may be used.

Next, the molecule Ji added as the fourth component in the present invention
Describes over 5,000 polymers.

If the requirements mentioned above are met, acrylic, polyester, urethane, epoxy, resin, polyamide,
Melamine, silicone, alkyd and others.

and modified products or combinations thereof.

Acrylic, polyester, and urethane alone or in combination are particularly effective in terms of both coating film performance and paintability. In this case, it may be a mixture of two or more of the same type of resin.

Here, the constituent components of the acrylic polymer will be described, but the present invention is not limited thereto.

For example, acrylic acid, methyl acrylate, ethyl acrylate, n-propyl acrylate, inglovir acrylate, n-butyl acrylate, isobutyl acrylate, full-n-amyl acrylate.

Acrylic acid alkyl esters such as n-hexyl acrylate and gl-n-octyl acrylate, acrylic acid-2
- Acrylics such as chloroethyl, acrylic acid, -3-chloropropyl? Shikumano Alkyl Rogenide, Acrylic Awakening
Acrylic acid-containing OH group esters such as 2-hydroxyethyl and 2-hydroxypropyl acrylate, and methacrylic acid.

Methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, in methacrylate, butyl-n-amyl methacrylate, n-octyl methacrylate,
α-alkyl acrylic acid alkyl esters such as lauryl methacrylate.

α-halogenated acrylic esters such as methyl α-chloroacrylate and ethyl α-chloroacrylate; α-alkyl acrylic acid halogenated alkyl esters such as 2-chloroethyl methacrylate and 3-chloropropyl methacrylate; and methacrylic acid. -2-hydroxylethyl,
2-hydroxyl globyl methacrylate, 1-chloro-2-hydroxyethyl methacrylate, and other α-alkyl acrylate entele having an OH group, and acrylic monomers containing epoxy groups such as glycidyl acrylate and glycidyl methacrylate; dimethylaminoethyl methacrylate, dimethylaminoethyl methacrylate,
Monomers having an amine group such as diethylaminoethyl methacrylate and diethylaminoethyl acrylate are included.

As component A of the present invention, it is preferable to use one or more of these acrylic monomers in an amount of 5 mm or more based on the total number of monomers, and for the remaining monomers, any monomer can be used as long as it can be copolymerized. It is possible.

Next, the constituent components of polyester will be described, but they are not limited to those exemplified below.

That is, alcohols include alkylene glycol type, ethylene glycol, dipropylene glycol,
Chlorpropylene glycol, butanediol (1,3
- or 1.4- or 2.3-) L3-methylbentanediol, 2,2-diethylpropanediol, pentamethylene glycol, 1,6-hexanediol, heptamethylene glycol.

Octamethylene glycol, nonamethylene glycol,
Alicyclic glycol types such as neopentyl glycol and hexamethylene diol, 1,4-cyclohexanediol, cyclohexane-1°4-dimetatool, and hydrogenated bisphenol A.

Polyalkylene glycol types include diethylene glycol, triethylene glycol, polyethylene gelicol, diglopylene glycol, polypropylene glycol, polytetramethylene glycol polybutadiene diol, etc., and aromatic glycol types include 2.2'
-Bis(4-hydroxyphenylpropane) (also known as bisphenol A), bis(4-hydroxyphenyl)methane (also known as hisphenol F) -4,4'-dihydroxyphenyl.

Phenols such as hydroquinone and resorcinol, alkylene oxide (ethylene oxide).

Examples include glycols obtained by adding propylene oxide, butylene oxide, etc.

Furthermore, as alkantriol type, glycerin,
Trimethylolmethane, trimethylolethane, trimethylolpropane + 1.2.6-hexandriol 1,2.3-butanetriol, l, δ.

3-pentanetriol, 2-methyl-2,3,4-butanetriol, 2-methyl-2,3,4-butanetriol, 2-methyl, -1,2,3-butanetriol, 2-ethyl-1 , 2', 3-butanetriol.

2-3.4-hexanetriol, pentamethylene glycol, etc., as alkanetetraols.

Erythritol, pentaerythritol, toilette,
1,2,3.4 pentanetetrol, 2,3,4.5
Hexanetetrol, 2,5-dimethyl-2,3,4,
5-hexanetetrol, 1,2,3.5-hentanetetrol, 3-hexene-1,2,5,6tetrol-3hexene-1,2,5,6-titrolnato, as an ether group-containing aliphatic triol , triols obtained by adding alkylene oxides (ethylene oxide, propylene oxide, butylene oxide, etc.) to glycerin, trimethylolpropane, etc.
Ether group-containing aliphatic tetraols include tetraols obtained by adding alkylene oxide to erythritol and pe/taerythritol, and aromatic triols include triols obtained by adding alkylene oxide to pyrogallol. It will be done.

Examples of carboxylic acids include chain or branched divalent carboxylic acids such as oxalic acid, malonic acid, and succinic acid.

Alicyclic dicarboxylic acids such as glutaric acid, itaconic acid, maleic acid, fumaric acid, adipic acid, sebacic acid, dodecanoic acid, methylene glutaric acid, methylmaleic acid, methylsuccinic acid, dodecenylsuccinic acid, tetrahydrophthalic acid, hexahydrophthalic acid , 6-methyltetrahydrophthalic acid, 6-methylhexahydrophthalic acid, endomethylenetetrahydrontalic acid, endoisopropylidenetetrahydrontalic acid + 1.4,5,6,7.7
-hexachloro-endo-! 5゛-Norbornene-2.
3-dicarboxylic acid (also known as het acid), 1,4,5,
6,7.7-hexapromoendo-5-norbornene-2,3-dicarboxylic acid, cyclohexane, 1,4-dicarboxylic acid, etc. Also, as aromatic dicarboxylic acids, phthalic acid, isophthalic acid, terephthalic acid, tetrachloro Examples include phthalic acid, tetrabromophthalic acid, and anhydrides thereof.

Next, let's talk about polyurethane. This may be of any type, such as urethanized oil type, moisture curing type, block type, catalyst curing type, or two-component type. Here, I will talk about isocyanates.

Constituent units of aliphatic diincyanate include ethane,
Propane, butene, thiodiethyl, pentane, β-methylbutane, hexane, ωld dipropyl ether, thiodipropyl, heptane, 2,2 dimethylpentane, 3-methoxyhexane, octane.

2.2,4) Limethylbentane, nonane, decane, 3
Butoxyhexane, 1,4 butylene glycol dipropyl ether ω, ω', undecane, totican.

Constituent units of aliphatic diisocyanates having a cyclic group such as thiodihexyl include ω, ω′ diincyanate 1
．． 3 Dimethylpenzole, ω, ω′ diisocyanate 1
．． 2 Dimethylpenzole, ω, ω′ diincyanate 1
, 2 dimethylcyclohexane, ω, ω' diincyanate, 1.4 cyclohexane, ω, ω' diincyanate 1,4 diethylpenzole, ω, ω' diincyanate 1,4 dimethylnaphthalene, l-ω-methylisocyanate-2-ω -n-propyl incyanate-3,5-
Dimethylcyclohexane, ω, ω'-diisocyanato n-propyl-biphenyl.

Examples of aromatic diisocyanates include tolylene diisocyanate, 3,3' bitrylene 4,4' diisocyanate, diphenylmethane 4,4' diisocyanate-3
, 3' dimethyldiphenylmethane 4,4' diincyanate, 2.4 tolylene diisocyanate dimer, and other aromatic incyanate constituent units Teij-1,3
Phenylene, 1,4 phenylene, l methylpenzole 2
, 4.1,3 dimethylpenzole 2,4゜1 ethylpenzole 2,4.1 inglobilbenzole, diisopropylpenzole, etc. Naphthalene incyanates include naphthalene 1.4-1,1' dinaphthyl 2. 2′ etc.
As biphenyl isocyanate, biphenyl 2.4
'-3,3' dimethylbiphenyl 4,4'-2 nitrobiphenyl 4,4'-, etc., as a constituent unit of diisocyanate of di, triphenylmethane, diphenylmethane 4
．． , 4', 2.2'dimethyldiphenylmethane4.
4', etc., the structural unit of tri- and tetraisocyanate is 1-methylpenzole 2,4,6,1,3.5
) Limethylbenzole 2.4.6-naphthalene 1.3
．． 'i',, biphenyl 2.4.4'-diphenylmethane 4.4'-3 methyldiphenylmethane 4,6゜4
', triphenylmethane 4,4.4'', diphenyl 4.
Other incyanates such as 4' diisocyanate N-carbamic acid chloride include phosphorus isocyanate, fluorinated isocyanate, and sulfonyl isocyanate. In addition, an appropriate molecular group or atomic group may be optionally introduced into the skeleton of these incyanates,
May be denatured.

Next, it is reacted with incyanato. Or already 1
I will talk about the polyols or polyethers that are reacting. These are at the end of one molecule.

RCOOH, H2S, R3H, HCN, H(J
,' HOH, HOH.

ROH, R(OH)2. NH3,RNH2,R(NH
,,)2. R8O□14H2+C,H6-AA 02
3, ie, a compound having an active (or reactive) hydrogen group such as a hydroxyl group, a carboxyl group, an amine group, or an active methylene group.

For example, as polyester, HOOC-R'-Co
・OR・0・co・R'・C0OH or +HO・R
It is represented by 0.CO.R'.C0-0-R-OH, and the constituent units already mentioned can be used as its constituent units. As a polyether, + HO-R・0・
R-0...R-0-R.OH, and its constituent units include ethylene oxide, propylene oxide, trimethylene oxide, butylene oxide, α-methyltrimethylene oxide, 3. 3
It is produced by ring-opening polymerization or copolymerization of cyclic ethers of '-dimethyltrimethylene oxide, trimethylene oxide, tetrahydrofuran, dioxane, dioxyamine, etc. (also called polyether glycol or polyoxyalkylene glycol).

Active hydrogen compounds other than snow include polyols obtained by hydrogenation of carbon oxide-olefin copolymers, or formaldehyde-modified polymers thereof, phenolaldehyde polycondensates, aldehyde-polyol polycondensates, and polycondensates of bisphenol A and epichlorohydrin. Epoxy resins obtained from the above, polythioethers, polyesteramides obtained from dicarboxylic acids and diamines or amide/alcohols, etc. are used alone or in combination with other polymers.

Above, the structural units of polyacrylic, polyester, and polyurethane have been described. What is important here is that these polymers have a C-C bond that is active to electron beams in the molecular skeleton, in the side chain, or at the end of the molecule, which was not mentioned above.
This means that you may have one. Regarding C=C amount,
When it is introduced into a polymer, it is difficult to introduce it in large numbers because it is complicated in terms of synthesis; however, conceptually, the more it is possible, the better the stain resistance, chemical properties, and hardness will be.

However, silica-based extender pigments will be discussed later.

The number of C2C bonds in the five molecules may be zero as long as the relationship between the amount of the polymer added and the average double bond position of other components is within the range.

Here, we will define one of the performance goals of the present invention: a coated metal plate with high hardness, excellent chemical resistance, and excellent stain resistance. What is excellent stain resistance? 1 Use the usual test method - apply magic ink, curry, curl, lipstick, crayon, colored pencils, ink, whiskey, and other daily necessities or substances commonly used in stain resistance tests and leave them for 24 hours after applying. and benzine alcohol, water, and other chemicals that dissolve contaminants.
Alternatively, it can be erased with cloth, gauze, etc. without leaving any traces, and even if letters or figures are written with a whiteboard marker, they can be erased with an eraser. Regarding chemical resistance, it has 5% hydrochloric acid and acetic acid.

Acids such as sulfuric acid, citric acid, nitric acid, etc., 5% strength soda.

Alkali such as ammonia, ethanol, benzine.

Methyl ethyl ketone, acetone, xylene, ethyl acetate, and other organic solvents are applied to the coating film, and a cover glass (e.g., a watch glass) is placed over it to prevent scattering. After leaving it for 24 hours, the side tube is removed. It is something that cannot be recognized or changed. In terms of hardness, it is '7H on lead scale hardness.
This refers to the above.

Here, oligo(meth)acrylate, polyhydric alcohol(meth)acrylate, silica-based extender pigment and molecular weight 50
0 I will talk about the quantitative relationship of Q or higher polymers.

The above two components are necessary to maintain coating film performance such as excellent stain resistance, chemical resistance, and hardness. , (Improvements in item (2)), it has been found through various examinations that it is rather a negative factor with respect to the target coating film performance of the present invention. Further, although the polymer itself improves paintability, it is a negative factor in terms of coating film performance.

This is because if a molecule has as many (meth)acryloyl groups that are active to electron beams as in oligo(meth)acrylates and polyhydric alcohols (meth)acrylates, Although it is not so negative, although something like this is theoretically possible, it is actually impossible to synthesize. Although the limit is not clear, for example, according to Ford Laotor's Japanese Patent Publication No. 45-15630, there are about three (meth)acryloyl groups per 1000 molecular weight, and in other words, the bipedal bond equivalent is about 330 or more.

Here, a quantitative relationship is required. As a result of various studies, the inventors of the present application discovered that a close relationship exists between the (meth)acryloyl group equivalent and the amount of silica-based extender pigment and polymer added. The average (meth)acryloyl group equivalent of oligo(meth)acrylate and polyhydric alcohol (meth)acrylate is X, the amount of silica-based extender pigment added is y (%),
If the amount of polymer added is Zc), then x>O5Z≧01
130 130 C, and the amount of silica-based constituents is in the range of 0.05 parts or more based on the total amount of resin such as oligo (meth) acrylate, polyhydric alcohol (meth) acrylate, polymer, etc.), then The objectives of the present invention are met, including the defined coating performance.

The above is a list of the four essential ingredients, but in addition to these.

Plasticizers, pigments, diluent monofunctional monomers, oligomers,
A solvent or the like can be added.

An example of a plasticizer is dioctyl adipate.

Dioctyl phthalate, diptyl 7-thaleate, dioctyl sebacate, triyneoctyl trimellitate, tri-2-ethylhexyl trimellitate, pyromellitic acid tetraester, 2.2-diphenolic acid ester, epoxidized linoleic acid, epoxidized soybean oil lacquer Although mold resins and other materials can be used, they should be kept to the minimum necessary for imparting workability to the painted plate.
In the case of white boards, etc., O is preferable.

As the pigment, rust preventive coloring and others may be used. For solvents: xylene, butyl acetate, methyl cellosol, ethyl cellosol, toluene.

Examples include inpropyl alcohol, butyl alcohol, ethyl acetate, 7775 morpholine, methyl ethyl ketone, acetone, and olefinic solvents, and one or more of them may be used to form a mixed bath agent.

In the prepainted steel sheet of the present invention, the original sheet may be a cut sheet or coiled iron sheet, or an electrogalvanized steel sheet.

Hot-dip galvanized steel sheets, or those that have already undergone chemical conversion treatment such as chromic acid or phosphoric acid treatment during the steel sheet manufacturing process,
Aluminum plates, stainless steel plates, steel plates, etc. can be used, but (electro)galvanized steel plates are one of the most suitable in view of the balance between the surface appearance of the coated product, cost, corrosion resistance, etc.

In addition, in the production of the present invention, various known methods can be used to pre-treat the metal plate, if necessary. It is sufficient to simply pre-treat the steel plate by simply washing it. For items that have not been chemically treated, use a chemical conversion treatment agent 1 depending on the material.
Examples include a phosphate treatment agent, a chromic acid treatment agent, a composite oxide film treatment agent, a heavy metal replacement treatment agent, and the like.

I cut it. It is better to use a primer between this original plate and the resin composition layer of the present invention.

A primer that has good adhesion to the base plate, has rust prevention properties, and has good adhesion to the top coat resin composition exhibits better performance when coated between the base plate and the resin composition of the present invention. It is.

The composition of this primer may be epoxy, modified epoxy, vinyl phenol-epoxy acrylic, polyester, etc., and the curing method of the primer may be any of heat, electron beam, ultraviolet, UV light, external radiation, and ultrafast infrared rays.

The primer can be applied by conventional methods such as natural roll coating, reverse roll coating, curtain flow coating, and spray coating, and the thickness of the coating film is about 1 to 10 μm, preferably 2 μm.
It is desirable that the thickness is about 5μ. As curing conditions, appropriate conditions are used depending on the respective curing method or resin components.

In addition, depending on the coating method, film thickness, and formulation conditions, a solvent may be added to the coating resin composition in the present invention in order to obtain an appropriate coating viscosity.
It is desirable to scatter the solvent before applying it and irradiating it with an electron beam.

The conditions for scattering this solvent are, for example, 300 m
Baking for a long time at very high temperatures near ℃ differs from the conditions for curing, and only requires the solvent to be scattered. -For example,
A drying hot air temperature of 150°C and a plate temperature of 120°C or less are sufficient. Alternatively, if the setting is sufficient, the solvent may be scattered by leaving it alone, and heating may not be necessary.

The method for irradiating electron beams after coating the resin composition in the present invention will be explained as follows.

Any known device, such as a DC high voltage electron gun or an electron beam irradiation device with an acceleration mechanism, can be used, and devices with accelerating voltages ranging from 100 kilovolts to several megavolts are currently being developed. However, in the present invention, a device of several hundred kilovolts is sufficient. Regarding the output current, from the viewpoint of high-speed productivity, a large current is particularly desirable, and an output current of 100 milliamperes/one accelerating tube or more is desirable.

Regarding the appropriate irradiation dose in the present invention, approximately 05 to 10
, Mrad is a rough guide, but 1 to 5 M
Although it depends on the resin composition, it shows good performance at about rad.

In general, when curing a coating film by irradiating electron beams, oxygen is known to act as a polymerization inhibitor, so it is preferable to block this out, and to replace the atmosphere with an inert gas, etc. Among these, it is desirable to perform electron beam irradiation. In particular, when emphasis is placed on the surface hardness, stain resistance/chemical resistance, water resistance, and tl[I inertia of the coating film, the first one has a significant meaning.

Examples of the inert gas include nitrogen gas, carbon dioxide gas, argon, helium, krypton, etc., but the oxygen concentration at the time of irradiation is approximately 1 or less - preferably 0.
A condition of about 1% or less is sufficient.

In order to prevent the coating film from being scratched on the pre-recorded steel plate of the present invention during loading of the coated product, transportation, and processing on the user's side, it is preferable to bond the protective film under pressure and heat. An example of a protective film is polyethylene divinyl chloride.

Examples include polypropylene, polyester, and acrylic.

, 2 2 Self: ``C... Example 1 A, an oligomer in which the condensation molar ratio of phthalate, trimethylolpronochloride, and acrylic acid is approximately 1:2:4 (acryloyl group equivalent: approximately 155) - B,) Methylolpropane trimethacrylate (acryloyl group: approx. 110) - C, silica-based extender pigment (Fuji Devin Chemical 'Syroid 308'' oil absorption 17'Or/1oof) -D
, ethyl acrylate, methyl methacrylate, hydroxyethyl methacrylate, acrylic acid copolymerization molar ratio is '7
Acrylic copolymer consisting of 0:24:3:3 (number average molecular weight approximately 20,000) -A, B-C, D and titanium white in a weight ratio of -18.8: 18.8: 1.8
: 4.4 : Add 3 xylene to the system consisting of 44.2
In addition to Section 0 (versus the former), it was used as paint.

Apply this paint system using a curtain flow coater (60 cr
n), an electrogalvanized steel plate (1500 x 600 x 0.6
myn) was painted.

The painted surface was beautiful, and there was hardly any dust visible.

This painted board was sprayed with solvent under conditions such that the board temperature reached 80°C (furnace time approximately 50 seconds) using 150°C hot air.
It was then cured with an electron beam.

Curing conditions: Voltage 300 KV - Current 25 mA/60 cm Dose 3 Mrad, Oxygen degree A during irradiation 150 ppm This cured coated plate was subjected to the stain resistance/chemical resistance test and coating film test such as hardness as described above.

(stain resistance) Magic ink (red, blue), curry, curl.

Apply lipstick, crayons, colored pencils, and ink to the painted board.

After 24 hours, it was easily wiped off with gauze soaked in ethanol without leaving any traces.

Also, even if I wrote on it with a whiteboard marker manufactured by Pilot Co., Ltd., it could be completely erased with an eraser.

(Dangerous chemicals) 5% hydrochloric acid, acetic acid, sulfuric acid, citric acid, nitric acid, hydric soda,
Ammonia etc. also. Approximately 1 cc of ethanol, benzine, methyl ethyl ketone, acetone-xylene, or ethyl acetate was dropped onto the coating film, covered with a watch glass, left for 24 hours to prevent scattering, washed with water, and then blown with air before being visually determined. However, no change was observed in the coating film.

(Pencil hardness 8.H) Reference Example 1 In order to measure the charging property of this coated plate, a 5ta
t,ic honestmeter Type S-4
104 with an applied voltage of 8 KV (charging voltage 1'7 mV), the application was stopped and the half-life, that is, the time until the charging voltage reached 85 mV, was measured and found to be about 60 seconds.

Comparative example 1, The paint system in Example 1 except for component C.

It was created under exactly the same conditions as before.

The performance after curing was almost the same as in Example 1, but there were noticeable stains and dust (visual observation: 2 pieces/10×10 on
) When the gloss within the same board was measured, the highest value was 82, the lowest value was 5B, and even when viewed as -, unevenness was felt.

When the charging characteristics of this sample were measured, the half-life was 105 seconds.

Comparative Example 2 A coating system was prepared under exactly the same conditions as in Comparative Example 1 except that the +c and D components were removed.

The performance after curing was almost the same as in Example 1, but
The surface of the painted board is not smooth and has "streaks", and dirt and dust are very noticeable (visual inspection: 4 pieces/10X10c+
n) and when the same Sakauchi gloss was determined as 11411,
The highest value was 87. The lowest value was 38, and uneven gloss was noticeable when viewed from below.

The charging characteristics of this sample were also measured.

The half-life was approximately 210 seconds.

Example 2 A, oligoacrylate with a condensation molar ratio of adipic acid, pentaerythritol, and acrylic acid of approximately 1:2:4 (1122 acryloyl group equivalents) B, diethylene glycol dimethacrylate (acryloyl group equivalent 121) -C, silica-based Extender pigment (Mizuka/Le NP manufactured by Mizusawa Chemical Industry Co., Ltd.)
-8, oil absorption 260g/100S')D, condensation molar ratio of terephthalic acid, sebacic acid, and ethylene glycol is approximately 3
:'7:10 polyester (molecular weight 15.Qo
o) A paint was prepared using components A, B, C, and D under exactly the same conditions as in Example 1, and after painting, the painted board was irradiated with an electron beam.

The coating film performance and paintability were exactly the same as in Example 1, and the results were excellent.

Example 3゜A, tetrahydrophthalic acid, trimethylolpropane,
Oligoacrylate with a condensation molar ratio of acrylic acid of approximately 1:2:4h (acryloyl group equivalent B, tetramethylolmethanetetraacrylate (acryloyl group equivalent: 88) C, silica-based extender pigment (Jiotsugi Pharmaceutical Carplex #)
1oO1 oil absorption 22oy/1ooy) D, polyester with a condensation molar ratio of inphthalic acid, sebacic acid, and diethylene glycol of approximately 2:8:10 (molecular weight approximately 9.0
00) /l The weight ratio of B, C, D and titanium white is 20:2
A paint was prepared by adding approximately 20% xylene (vs. the former) to a system consisting of 0:2:5:45. Implemented this paint system ju131
Coated plates were prepared by electron beam curing under exactly the same conditions as (with the only difference being the oxygen concentration during irradiation, here 500 ppm).

The paintability and film performance showed similar results to those of Example 1.

Example 48 Even if an oligoacrylate (acryloyl group 1ft approximately 130) having a condensation molar ratio of fucuric acid, glycerin, and acrylic acid of 1:2:4 is used in place of component A in Example 3,
The paintability and film performance showed similar results to those of Example 1.

Example 5 Even when half the amount of component A in Example 3 was replaced with component A in Example 2, the paintability and film performance were the same as in Example 3.

Example 6 In Example 1, even if half of the C component was replaced with the C component in Example 2, the paintability and film performance were still 1. )1~Works 2 2...Painted plate 3...Gas sampling tube for oxygen analyzer 4...Inert gas supply pipe 1~7 5...Electron beam irradiation window 6...Scan horn fan 1 day 2

Claims (2)

[Claims] (1) An oligo(meth)acrylate containing two or more (meth)acryloyl groups in one molecule and having a (meth)acryloyl group equivalent of 500 or less, and an oligo(meth)acrylate containing two or more (meth)acryloyl groups in one molecule. And, a paint containing as essential ingredients 1 alcohol (meth)acrylate with a (meth)acryloyl group equivalent of 150 or less, a silica-based extender pigment, and a polymer with a molecular weight of 5,000 or more is applied to the object to be coated, and this is applied to an oxygen concentration of 1 1. A method for producing a coated metal plate, which comprises curing the coated metal plate with an electron beam in an inert gas of less than 100 mL. (2) An oligo(meth)acrylate containing two or more (meth)acryloyl groups in one molecule and having a (meth)acryloyl group equivalent of 500 or less, and an oligo(meth)acrylate containing two or more (meth)acryloyl groups in one molecule. and a polyhydric alcohol (meth)acrylate having a (meth)acryloyl group equivalent of 150 or less, a silica-based extender pigment 1
An electron beam curable coating composition containing a polymer having a molecular weight of 5,000 or more as an essential component.