JPS621660B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an electron beam curable coating composition for precoated metal that has excellent mechanical properties of the coating film. Precoated metal is a material that is painted or coated before processing, and its production has increased significantly in recent years as it provides a significantly more streamlined manufacturing method for metal products compared to conventional methods such as press working that are coated after processing. ing. The most common method for manufacturing such pre-coated metal is to apply a thermosetting paint to a surface-treated metal plate by an appropriate means and heat cure it. Alternatively, a method of heating and pressurizing thin films or laminating them with adhesive via an adhesive layer is also used. Precoated metal is mainly used for both outdoor applications such as roofing materials and side walls of houses, and indoor applications such as interior walls, cabinets, and home appliances, so in addition to corrosion resistance, it is also weather resistant for outdoor applications. High processability, stain resistance, and chemical resistance are particularly required for indoor applications. Furthermore, there are many required performance items such as water resistance, boiling water resistance, hardness, and aesthetic appearance, and the level thereof is extremely high. Among these required performances, the present inventors have continued to study workability, especially improving bending workability, and have found that the paint film has excellent stain resistance, chemical resistance, water resistance, and The present inventors have succeeded in obtaining a coating composition of the present invention that provides a coating film with high coating film hardness and excellent workability without impairing various properties such as water boiling properties. Processability here refers to the ease of processing and the degree of damage resistance when forming a flat plate of pre-coated metal into shapes for various end uses. In other words, it can be said that the precoated metal has good workability because the coating film is less damaged in processes such as bending, drawing, extrusion, and cutting. There are various known examples of methods for producing precoated metal by electron beam curing and coating compositions used therein. However, the workability of both methods was insufficient, and improvements were desired. This is because, from the viewpoint of the durability of the coating film, it is preferable that the crosslinking density is high and the hardness is high, but from the viewpoint of processability, both of these factors act in an unfavorable direction. In view of the above circumstances, the inventors of the present invention have conducted extensive studies on the problem of improving workability while maintaining high crosslinking density and hardness, and have now completed the present invention. That is, the present invention has a number average molecular weight in the range of A 8000 to 400000,
The main component is one or more of acrylic esters or α-substituted acrylic esters,
Saturated or unsaturated acrylic copolymer with a glass transition point in the range of -50 to 20°C 10 parts B having a number average molecular weight in the range of 8000 to 400000,
The main component is one or more of acrylic esters or α-substituted acrylic esters,
The glass transition point is in the range of 10 to 70°C, and the glass transition point is at least 2°C higher than that of the component A.
or more highly saturated or unsaturated acrylic copolymer 1 to 100 parts C A polyfunctional vinyl monomer having a molecular weight of 2000 or less and having two or more radically polymerizable double bonds in one molecule as both components A and B. total of 100
The gist thereof is an electron beam curable coating composition containing 5 to 100 parts of the main resin component and having excellent mechanical properties of the coating film. The coating composition of the present invention combines an acrylic copolymer with a low glass transition point and an acrylic copolymer with a high glass transition point, so it has good processability obtained by a flexible coating film based on the characteristics of the former, and the characteristics of the latter. Based on this, it is possible to successfully develop the good surface properties and durability that can be obtained from a hard coating film.
Furthermore, since the radically polymerizable polyfunctional vinyl monomer that acts as a crosslinking agent is cured by electron beam irradiation, it is possible to form a coating film that is densely crosslinked and has excellent durability, stain resistance, and chemical resistance. Acrylic acid in components A and B, or α-
Examples of substituted acrylic esters include, but are not limited to, the following. For example, methyl acrylate, ethyl acrylate, n-propyl acrylate, isobutyl acrylate, n-amyl acrylate,
Alkyl acrylates and cycloalkyl esters such as n-hexyl, cyclohexyl acrylate, n-octyl acrylate, diacrylic acid
- Alkyl acrylate halides such as chloroethyl, 3-chloropropyl acrylate, 2-hydroxyethyl acrylate, 2-acrylate
Acrylic acid hydroxyalkyl esters with OH groups such as hydroxypropyl, acrylic esters containing ether rings such as glycidyl acrylate, and tetrahydrofurfuryl acrylate, acrylic esters containing aromatic rings such as benzyl acrylate, and methacrylic acid. Methyl, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, cyclohexyl methacrylate, n-amyl methacrylate, n-octyl methacrylate, lauryl methacrylate, etc. α of
-alkyl and cycloalkyl acrylates, α-methyl chloroacrylate, α
- α-halogen acrylic esters such as ethyl chloroacrylate, α-alkyl acrylic acid halogenated alkyl esters such as 2-chloroethyl methacrylate, 3-chloropropyl methacrylate, 2-hydroxyethyl methacrylate, methacrylic acid -2-hydroxypropyl, 1-chloro-2-hydroxyethyl methacrylate, etc.
α-alkyl acrylate ester with OH group,
Examples include methacrylic esters containing an ether ring, such as glycidyl methacrylate and tetrahydrofurfuryl methacrylate, and methacrylic esters containing an aromatic ring, such as benzyl methacrylate. In the present invention, one or two of these acrylic esters or α-substituted acrylic esters
For the acrylic copolymer of both components A and B, it is preferable to use at least 50% by weight of the total monomer. Any other polymerizable compound may be used as the remaining monomer. The glass transition point refers to the temperature at which a polymer changes from a hard, glass-like state to a rubber-like state, and is generally a measure of the hardness or softness of a polymer. Component A is a soft resin component having a glass transition point in the range of -50°C to 20°C, preferably -10°C to 20°C;
The component is a hard resin component in the range of 10-70°C, preferably 10-50°C. When the difference in the glass transition points of these components A and B is 2° C., preferably 5° C. or more, the respective desirable characteristics of both components are fully exhibited. Preferred performance is obtained when the glass transition point of the resin containing both components A and B is in the range of -5°C to 40°C. These acrylic copolymers can exhibit the effects of the present invention whether or not they have unsaturated bonds in their molecules. An unsaturated bond can be introduced into the side chain or the end of the main chain by utilizing the reactivity of the functional group. If the amount of unsaturated groups is too large, the crosslinking density will be excessive and the processability will be reduced.
The number of unsaturated groups is preferably 0.3 or less. The composition ratio of the A and B component copolymers must be such that the A component is 10 parts and the B component is 1 to 100 parts. If this range is exceeded, only the characteristics of one component will be exhibited, and it will be impossible to simultaneously achieve high levels of hardness and workability, which are the characteristics of the present invention. The polymerization method for these acrylic copolymers may be any one of solution, suspension, and emulsion polymerization methods. The copolymer needs to have a relatively large number average molecular weight of 8,000 to 400,000 as determined by gel permeation chromatography, osmotic pressure method, end group determination method, etc. If the molecular weight is less than 8000, sufficient mechanical strength of the coating film cannot be obtained and processability is poor. On the other hand, if it is larger than 400,000, the fluidity of the coating film will be insufficient and a coating film with a good surface condition will not be obtained. The polyfunctional vinyl monomer having a molecular weight of 2000 or less as component C refers to a compound having two or more radically polymerizable double bonds in the same molecule. Among these are: a ethylene glycol dimethacrylate or diacrylate. b Polyethylene glycol dimethacrylate or diacrylate with a molecular weight of 2000 or less. c Propylene glycol dimethacrylate or diacrylate. d Polypropylene glycol dimethacrylate or diacrylate with a molecular weight of 2000 or less. e Trimethylolpropane trimethacrylate or triacrylate. f Pentaerythritol trimethacrylate or triacrylate. g A phosphate ester-based polyfunctional monomer such as trisacryloxyethyl phosphate. h A polyfunctional monomer having a divalent or higher valence isocyanate and an unsaturated group. For example, a compound obtained by reacting hexamethylene diisocyanate alone or an adduct, or tolylene diisocyanate alone or an adduct with 2-hydroxyethyl methacrylate. i Allyl compounds such as diallyl phthalate, diallyl maleate, diallylitaconate. j Divinylbenzene. k Unsaturated epoxy ester obtained by the reaction of epoxy resin and unsaturated acid with a molecular weight of 2000 or less. l A polyfunctional monomer obtained by adding an unsaturated acid to glycidyl methacrylate or glycidyl acrylate. m A polyfunctional monomer obtained by adding glycidyl methacrylate or glycidyl acrylate to a polyvalent carboxylic acid. A polyfunctional monomer obtained by adding glycidyl methacrylate or diacrylate to an n amino compound. o A polyfunctional monomer obtained by adding an unsaturated alcohol to a compound having a glycidyl group. p A polyfunctional monomer obtained by adding polyhydric alcohol and glycidyl methacrylate or glycidyl acrylate. q A polyfunctional monomer obtained by reacting glycerin with an unsaturated carboxylic acid. r An esterification product of a terminal OH group polyester and an unsaturated acid with a molecular weight of 2000 or less. s A polyfunctional monomer obtained by the reaction of a polyhydric alcohol and an unsaturated carboxylic acid, other than those listed in items a to f. The properties required of these polyfunctional monomers include the ability to be cured by electron beam irradiation, the ability to form crosslinked network bonds with the acrylic copolymer to form a strong film structure, and the ability to form a strong film structure as a coating film. nature,
It is important that stain resistance, chemical resistance, water resistance, etc. are not adversely affected. These polyfunctional vinyl monomers are used in an amount of 5 parts per 100 parts of the total weight of components A and B.
It is necessary to use a range of ~100 parts. 5
If the amount is less than 100 parts, the coating film will be insufficiently cured and its solvent resistance will be poor, and if it exceeds 100 parts, the flexibility of the coating film will be reduced and its mechanical properties will be poor. The reason why the molecular weight is 2000 or less is because it is preferable in terms of compatibility with the acrylic copolymer and handling properties as a liquid. In addition to the above-mentioned main components A, B, and C, a monoductal vinyl monomer, a volatile diluent, and the like may be added as necessary. Single-tube vinyl monomers are divided into volatile and non-volatile ones, but volatile ones cannot be used as coating film components and are therefore used only as diluents. Typical examples of these include methyl methacrylate, methyl acrylate,
Examples include ethyl acrylate, butyl acrylate, and vinyl acetate. Most of the non-volatile polymerizable diluent is mixed into the cured coating film after curing. Therefore, it has a large effect on the performance of the coating film, and it is necessary to pay sufficient attention to its selection. These include higher fatty acid ester acrylates or methacrylates such as cyclohexyl methacrylate, ethylhexyl methacrylate, isodecyl methacrylate, and lauryl methacrylate, styrene, vinyltoluene, and the like. Non-polymerizable diluents are limited to volatile ones. Most of these non-polymerizable diluents must be evaporated by an evaporation process or forced heat drying before electron beam irradiation. If a large amount remains, serious defects often occur in the processing adhesion, water resistance, chemical resistance, etc. of the coating film. Furthermore, the polymerization solvent used in the synthesis of the acrylic copolymers of components A and B and the solvent used in the synthesis of the polyfunctional vinyl monomer of component C can also be used subsequently as diluents. Examples of such diluents include the following. These include ethyl acetate, butyl acetate, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, methyl isobutyl ketone, isopropyl alcohol, toluene, and xylene. The amount of diluent required is governed by the appropriate viscosity at the time of application. This appropriate viscosity depends on the coating method, type of coating machine,
The amount of diluent used can be adjusted to any desired ratio since it varies greatly depending on the coating speed, film thickness, and degree of surface condition. In addition to the above-mentioned components, other components can be added to the present composition as long as the gist of the present invention is not impaired. Such ingredients include pigments, fillers, surfactants, etc. for coloring, coloring effects, etc.
These include dispersants, plasticizers, ultraviolet absorbers, and antioxidants. The proportions of these components in the composition can vary within a wide range depending on the performance required of the final product. This composition has the best characteristics when used as a coating on various types of iron plates (for example, untreated bare steel plates, zinc-treated steel plates, zinc phosphate-treated steel plates, etc.) and thin metal plates for pre-coated metal such as aluminum thin plates. demonstrate. When a painted film is formed on such a base material, due to the excellent workability of the cured film, these painted plates can be pressed into various shapes,
Can be extruded. The coating structure of the present composition on a substrate can have various structures such as a single layer structure made of a single composition or a multilayer structure made of two or more layers made of different compositions. In particular, when a high degree of corrosion resistance is required, such as in the case of colored iron plates, the lower layer may contain this composition or any other composition containing a corrosion-resistant pigment,
The upper layer may have a multilayer structure using the present composition containing a colored pigment. Further, when a high degree of processability is required, a primer with good adhesion to the base material can be used as the lower layer, and the present composition with good processability can be applied as the upper layer. Various methods are possible for forming a thin film structure using this composition. for example,
Methods such as spraying, roller coating, curtain flow coating, casting, and knife edge coating are possible. It is also possible to apply heat or pressure to reduce the viscosity of the coating. A method of curing this composition is to irradiate it with high-energy electron beams. High-energy electron beams are electron beams with acceleration energy of 0.1 to 3.0 MeV, and include Kotscroft type, Kotscroft-Walton type, Van de Graaff type, resonant transformer type, insulated core transformer type, linear type, and dynamitron type. , refers to those emitted from various types of electron beam accelerators, such as high-frequency types. The irradiation amount can be freely changed within a wide range depending on the required coating hardness and coating performance, but if it is less than 0.1M rad, the coating hardness will be insufficient and 20M
A range of 0.1 to 20M rad is appropriate, since excessive crosslinking will occur if it exceeds rad, resulting in a coating film lacking in flexibility. The atmosphere during irradiation is preferably an inert gas such as nitrogen, carbon dioxide, helium, argon, neon, or combustion gas, since oxygen has the effect of inhibiting or suppressing curing. The coating film made from the above-described composition of the present invention can sufficiently satisfy various required properties, such as weather resistance, corrosion resistance, processability, chemical resistance, stain resistance, water resistance, and boiling water resistance. Among these, remarkable improvements were achieved that were unprecedented, especially in workability. By using two types of acrylic copolymers with relatively high molecular weights and different glass transition points,
This is due to the phenomenon that the hardness of the coating film is high and the processability is good. In other words, a polymer with a high glass transition point increases hardness, and a polymer with a low glass transition point improves processability, which are both characteristics that can be clearly expressed in the present composition. It is from. This kind of performance is particularly effective in the field of pre-coated metals, which have high workability and durability. Examples according to the present invention are shown below. Example 1 (1) Polymerization of acrylic copolymer (A-1) A four-necked flask (2
) was prepared, and a monomer solution with the following composition was prepared and mixed. Methyl acrylate 80.4g Ethyl acrylate 44.2g Methyl methacrylate 5.4g N,N'dimethylaminoethyl methacrylate
1.2g Toluene 65.6g Butyl acetate 65.6g Azobisisobutyronitrile 0.16g The above mixture was polymerized by stirring at 70°C under a nitrogen stream. After 3 hours, the solution became highly viscous due to the polymerized polymer. Next, a monomer solution having the following composition was prepared and added dropwise to the above solution over 4 hours, and polymerization was continued at 70°C. Methyl acrylate 142.9g Ethyl acrylate 78.6g Methyl methacrylate 9.6g N,N'dimethylaminoethyl methacrylate
2.1g toluene 83.2g ethyl acetate 50.4g butyl acetate 99.6g azobisisobutyronitrile 0.19g Next, butyl acetate 182.1g azobisisobutyronitrile 0.07g were added dropwise over 2 hours, and polymerization was continued at 70°C. Ta. Polymerization was further continued at 70° C. for 5 hours to complete polymerization of unreacted monomers. After the polymerization was completed, the following were added. Butyl acetate 130.1g Hydroquinone monomethyl ether 0.55g The solid content of the obtained acrylic copolymer solution is
33.5%, the number average molecular weight of the polymer is 73000 as measured by gel permeation chromatography.
It was hot. The glass transition point of this copolymer measured by differential calorimetry was 5°C. (2) Polymerization of acrylic copolymer (B-1) Polymerization was performed in the same manner as in the polymerization of A-1 described above. First, a monomer solution having the following composition was polymerized at 70°C for 5 hours. Methyl acrylate 80.4g Ethyl acrylate 23.0g Methyl methacrylate 26.6g N,N'dimethylaminoethyl methacrylate
1.18g Toluene 46.8g Ethyl acetate 28.3g Butyl acetate 56.0g Azobisisobutyronitrile 0.16g Next, a monomer solution having the following composition was added dropwise to the above solution over 6 hours, and polymerization was continued at 70°C. Methyl acrylate 142.9g Ethyl acrylate 40.8g Methyl methacrylate 47.3g N,N'dimethylaminoethyl methacrylate
2.10g toluene 83.2g ethyl acetate 50.4g butyl acetate 99.6g azobisisobutyronitrile 0.19g Next, butyl acetate 182.1g azobisisobutyronitrile 0.07g were added dropwise over 2 hours, and polymerization was continued at 70°C. Ta. Polymerization was further continued at 70° C. for 5 hours to complete polymerization of unreacted monomers. After the polymerization was completed, the following were added. Butyl acetate 130.1g Hydroquinone monomethyl ether 0.55g The solid content of the obtained acrylic copolymer solution is
33.6%, the number average molecular weight of the polymer was 75,000, and the glass transition point was 21°C. (3) Polymerization of Comparative Example Acrylic Copolymer (X-1) Polymerization was performed in the same manner as in the polymerization of A-1 described above. First, a monomer solution having the following composition was polymerized at 70°C for 4 hours. Methyl acrylate 80.4g Ethyl acrylate 33.6g Methyl methacrylate 16.0g N,N'dimethylaminoethyl methacrylate
1.18g Toluene 46.8g Ethyl acetate 28.3g Butyl acetate 56.0g Azobisisobutyronitrile 0.16g Next, a monomer solution having the following composition was added dropwise to the above solution over 5 hours, and polymerization was continued at 70°C. Methyl acrylate 142.9g Ethyl acrylate 59.7g Methyl methacrylate 28.4g N,N'dimethylaminoethyl methacrylate
2.10g toluene 83.2g ethyl acetate 50.4g butyl acetate 99.6g azobisisobutyronitrile 0.19g Next, butyl acetate 182.1g azobisisobutyronitrile 0.07g were added dropwise over 2 hours, and polymerization was continued at 70°C. Ta. Polymerization was further continued at 70° C. for 5 hours to complete polymerization of unreacted monomers. After the polymerization was completed, the following were added. Butyl acetate 130.1g Hydroquinone monomethyl ether 0.55g The solid content of the obtained acrylic copolymer solution is
33.6%, the number average molecular weight of the polymer was 74,000, and the glass transition point was 13°C. (3) Production of paint Using the acrylic copolymer obtained above, a paint was produced using a three-roll paint forming device.
The coating composition is shown in Table 1.

【table】

[Table] (4) Manufacture of coated plate Electrogalvanized steel plate coated with 2μ thick epoxy primer and heat cured (0.6mm thick)
Next, apply the paint obtained above using a bar coater and apply 130
It was placed in a hot air oven at ℃ for 3 minutes to volatilize the thinner. This coated plate was then exposed to voltage under a nitrogen stream.
2M with 300KV, 65mA current ICT electron beam accelerator
irradiated with rad electron beam. (5) Performance evaluation

[Table] As can be seen from the data in the table, the bending processability of the coating film created by the mixed system of acrylic copolymers A-1 and B-1 (the measured glass transition temperature of the mixed copolymers is 13°C) is It is superior to the coating film using acrylic copolymer X-1 whose temperature is 13°C. Example 2 (1) Polymerization of Comparative Example Acrylic Copolymer (X-2) Polymerization was performed in the same manner as in the polymerization of A-1 described above. First, a monomer solution having the following composition was polymerized at 70°C for 4 hours. Methyl acrylate 80.4g Ethyl acrylate 29.3g Methyl methacrylate 20.3g N,N'dimethylaminoethyl methacrylate
1.18g Toluene 46.8g Ethyl acetate 28.3g Butyl acetate 56.0g Azobisisobutyronitrile 0.16g Next, a monomer solution having the following composition was added dropwise to the above solution over 5 hours while polymerization was continued at 70°C. Methyl acrylate 142.9g Ethyl acrylate 52.1g Methyl methacrylate 36.0g N,N'dimethylaminoethyl methacrylate
2.10g toluene 83.2g ethyl acetate 50.4g butyl acetate 99.6g azobisisobutyronitrile 0.19g Then, butyl acetate 182.1g azobisisobutyronitrile 0.07g were added dropwise over 2 hours, and polymerization was continued at 70°C. Ta. Polymerization was further continued at 70° C. for 5 hours to complete polymerization of unreacted monomers. After the polymerization was completed, the following were added. Butyl acetate 130.1g Hydroquinone monomethyl ether 0.55g The solid content of the obtained acrylic copolymer solution is
33.6%, the number average molecular weight of the polymer was 76,000, and the glass transition point was 16°C. (2) Production of paint Acrylic copolymers A-1 and B- obtained above
A paint was produced using a three-roll paint forming apparatus using 1,X-2. The composition of the paint is shown in Table 3.

[Table] (3) Manufacture of coated plates Electron beam-cured coated steel plates were produced in exactly the same manner as in Example 1 using the paints shown in Table 3. (4) Performance evaluation

[Table] As can be seen from the data in Table 4, the bending processability of the coating film obtained by mixing acrylic copolymers A-1 and B-1 in this example (the glass transition point of the mixed copolymer is 16°C) is This is superior to the coating film using acrylic copolymer X-2, which has a transition point of 16°C. Example 3 (1) Polymerization of acrylic copolymer Using the monomer composition shown in Table 5, a four-necked flask was

[Table] Polymerization was carried out in (2) with 350 g of butyl acetate and 0.46 g of azobisisobutyronitrile with stirring at 70°C under a nitrogen stream. After 4 hours had passed, 150 g of butyl acetate and 0.16 g of azobisisobutyronitrile were added, and the polymerization was continued for another 6 hours. Thereafter, 150 g of butyl acetate and 0.22 g of hydroquinone monomethyl ether were added and stirred thoroughly. The number average molecular weight and glass transition point of the obtained acrylic copolymer are shown in Table 6.

[Table] (2) Production of paint Acrylic copolymers A-2 and B- obtained above
A paint was produced using a three-roll paint forming apparatus using No. 2,X-3. The coating composition is shown in Table 7.

【table】

[Table] (3) Manufacture of coated plate A coated steel plate cured by electron beam was produced using the paint shown in Table 7 in exactly the same manner as in Example 1. (4) Performance evaluation

[Table] As can be seen from Table 8, acrylic copolymer A
-2 and B-2 (glass transition point of the mixed copolymer is 15°C) in this example (glass transition point of the mixed copolymer is 15°C). It is superior to Example 4 (1) Production of unsaturated acrylic copolymer Acrylic copolymer A obtained in Example 3
-2, B-2, and X-3 were used to produce a copolymer in which a double bond was introduced into the side chain. That is, each copolymer solution (solid content 34.0%)
0.25 parts of glycidyl methacrylate per 100 parts, 0.002 parts of triethylbenzylammonium chloride
1 part and allowed to react at 110°C for 8 hours. The acid value was 1.95 before the reaction started, but
The acid value had become 0.49 due to the reaction. This indicates that the carboxyl group in the copolymer reacted with glycidyl methacrylate, and a double bond was introduced into the side chain. (2) Production of paint A paint was produced using the unsaturated acrylic copolymer obtained above. The coating composition is shown in Table 9.

【table】

[Table] (3) Manufacture of coated plate The primer obtained above was applied onto an electrogalvanized steel plate (thickness: 0.6 mm) to a solid film thickness of 3 μm. This was placed in an oven at 130°C for 1 minute to volatilize the thinner. Furthermore, on the primer,
The top coat obtained above was applied to a solid film thickness of 25 μm. This was placed in an oven at 130°C for 3 minutes to volatilize the thinner. Next, electron beam irradiation was performed in the same manner as in Example 1. (4) Performance evaluation Table 10 shows performance evaluation data for the examples and comparative examples.

【table】

[Table] From Table 10 above, acrylic copolymers A-2D, B
It can be seen that the bending processability of the coating film produced by the -2D mixed system is superior to that of a single copolymer having the same glass transition point.

Claims (1)

[Claims] 1. A having a number average molecular weight in the range of 8,000 to 400,000, containing one or more of acrylic esters or α-substituted acrylic esters as a main component, and having a glass transition point of -50 to 20. 10 parts B of a saturated or unsaturated acrylic copolymer having a number average molecular weight in the range of 8,000 to 400,000;
The main component is one or more of acrylic esters or α-substituted acrylic esters,
The glass transition point is in the range of 10 to 70°C, and the glass transition point is at least 2°C higher than that of the component A.
or more highly saturated or unsaturated acrylic copolymer 1 to 100 parts C A polyfunctional vinyl monomer having a molecular weight of 2000 or less and having two or more radically polymerizable double bonds in one molecule as both components A and B. total of 100
An electron beam curable coating composition containing 5 to 100 parts of the main resin component and having excellent mechanical properties of the coating film.