JPS5943067B2 - Photocurable coating composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a photocurable coating composition with excellent adhesion, electrical insulation, heat resistance, corrosion resistance, etc.

Conventionally, photocurable compositions mainly contain acrylates such as epoxy acrylate, epoxy methacrylate, and polyester acrylate, and ordinary unsaturated polyesters. However, these acrylates have poor adhesion to metals, and are used for limited practical purposes. The present invention aims to improve this drawback, and provides a photocurable coating composition that provides a coating film with particularly excellent electrical insulation properties compared to the above-mentioned acrylates and ordinary polyesters. That is, the present invention provides (^) 100 to 50% by weight of a hydrogenated diene polymer having at least one terminal functional group capable of forming an ester bond; (2) a hydrogenated product having at least one terminal functional group capable of forming an ester bond; 0 to 50% by weight of an unhydrogenated diene polymer and (C) an unsaturated polyester synthesized from an unsaturated polybasic acid (I), a vinyl monomer (■), and a photosensitizer field. The present invention relates to curable coating compositions.

The present invention is characterized by the use of the unsaturated polyester (I), which provides excellent adhesion, heat resistance, and electrical insulation properties compared to other photocurable resin compositions, and
By photo-curing, it becomes excellent in corrosion resistance.

For this reason, the unsaturated polyester (I) is (
2) As a component, a hydrogenated diene polymer having a functional group capable of forming an ester bond at its terminal is used. The hydrogenation rate of the hydrogenated diene polymer is preferably 90 to 100%, and the amount used is 100% to the total amount of components (2) and (m).
~50% by weight. If it is less than 50% by weight, heat deterioration resistance and weather resistance will be poor.

([component is necessary for the composition according to the present invention to have excellent drying properties, and especially when the hydrogenation rate of the hydrogenated diene polymer of component (2) is 100%, (Aj and (B It is preferable to use component (2) in combination.If the hydrogenated diene polymer used in the present invention has a small molecular weight, it is difficult to obtain a product with a high elongation rate, and it is usually 1,000 to 4 , 000 range, the desired composition can be obtained. Examples of diene polymers include propane diene, 1,2-butadiene, 1,3-butadiene, 1,
It is a polymer obtained by polymerizing at least one monomer selected from 3-pentadiene, 1,4-pentadiene, 1,5-hexadiene, etc.

In particular, polybutadiene is cited as being the most readily available and achieving the object of the present invention. The diene polymer used has at least one functional group capable of forming an ester bond at its terminal, and it is generally a hydroxyl group or a carboxyl group. To synthesize a diene polymer and introduce a functional group into it, a lipping polymer is first produced by polymerizing a diene compound in the presence of a metal catalyst such as sodium or lithium. Next, the lipping polymer is reacted with an epoxy compound to synthesize a product having a hydroxyl group at the end, and a product having a carboxyl group at the end by reacting with carbon dioxide. Here, the terminus may be one end or both ends of the ripping polymer. The unhydrogenated diene polymer thus obtained can be used as component (B).
Furthermore, by hydrogenating this polymer, a hydrogenated diene polymer can be obtained. The hydrogenation method uses organic solvents such as methanol, ethanol, cyclohexane, benzene, and tetrahydrofuran in the presence of a Raney nickel catalyst, Urushihara catalyst, and stabilized nickel catalyst at a reaction temperature of 50 to 300°C and a hydrogen pressure of 50 to 500 k9/ There is a method of carrying out the reduction reaction under the conditions of d. Further, examples of the unsaturated polybasic acid (O component) used in the present invention include maleic acid, maleic anhydride, fumaric acid and itaconic acid.

In the present invention, when producing an unsaturated polyester resin from an unsaturated polybasic acid, the glycol compounds used include ethylene glycol, diethylene glycol, 1,2-propylene glycol, dipropylene glycol, 1,3-
Examples include butylene glycol, 2,3-butylene glycol, bisphenol dioxyethyl ether, neopentyl glycol, 1,4-butene glycol, 1,4-hexanediol, and examples of saturated acids include adipic acid and sebacic acid. , phthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, 3,6-endomethylenetetrahydrophthalic anhydride, tetrahydrophthalic acid, etc. may be partially used in combination. When producing an unsaturated polyester resin, a catalyst can be used to promote the condensation reaction, and the type and amount used are not particularly limited.

This can be carried out by a conventional method for producing unsaturated polyester. Examples of the vinyl monomer () used in the present invention include styrene, vinyltoluene, α-methylstyrene,
Divinylbenzene, diallyl phthalate, acrylic acid esters or methacrylic acid esters (2-hydroxyethyl acrylate, 1,6-hexanediol diacrylate, trimethylolpropane triacrylate,
(polyethylene glycol diacrylate, etc.) may be used alone or in combination of two or more.

The amount of reactive monomer is 0.0% relative to the unsaturated polyester (1).
It is preferably used in an amount of 5 to 5 times by weight, particularly 0.5 to 2 times by weight. If it is less than 0.5 times by weight, the resulting photocurable resin composition tends to have a high viscosity, and if it exceeds 5 times by weight, the final coating film obtained becomes brittle.

In addition, as the photosensitizer used in the present invention, benzoin, benzoin ethyl ether, penzone isoflobucel, benzoin phenyl ether, benzoin alkyl ethers, benzothioethers, benzophenone, acetophenone, 2- Ethyl anthraquinone, decyl chloride, etc. can be used. The amount of photosensitizer (111) used is 0.5 to 10% by weight based on the total polymerizable components.
, particularly preferably 1 to 5% by weight.

If it is less than 0.5% by weight, the curing speed will be slow;
If it exceeds 100%, it tends to become difficult to form a film.

Note that a radical initiator can be added to the photocurable resin composition according to the present invention. This allows, for example, when the composition is applied to a workpiece with a complex formation, etc., and therefore, even if there are areas where light does not pass through or is insufficiently transmitted, it is possible to accelerate the curing of such areas. be able to.
However, in this case, it is cured by heating. The amount of the radical initiator added is preferably 0.5 to 5% by weight, particularly 1 to 3% by weight based on the total polymerizable components. If it exceeds 5% by weight, there is a risk that the composition will gel during storage.

Examples of radical initiators include acyl peroxides such as benzoyl peroxide and acetyl peroxide, hydroperoxides such as tertiary butyl peroxide and kyumene hydroperoxide, ketone peroxides such as methyl ethyl ketone peroxide and cyclohexanone peroxide, and tertiary peroxides. Oxyperoxides such as butyl peroxide and dicumyl peroxide are used. In addition, when using a radical initiator, iron, cobalt, lead,
Naphthenates, octenoates, etc. of metals such as manganese, nickel, tin, and zinc can be used in combination. The amount used is preferably 0.5 to 5% by weight, particularly 1 to 3% by weight. In the present invention, materials other than those mentioned above may be mixed.

Such materials include fillers and reinforcing materials such as aluminum hydroxide, calcium carbonate, silicon dioxide, alumina, glass fibers, and organic fibers. Next, examples of the present invention will be shown. Example 1 Polybutadiene glycol with a molecular weight of 2,000 (1.2
- 90% vinyl, 10% 1,4-trans) 1009 was placed in a 11 autoclave, and the hydrogen pressure was 120 kg/C.
The reduction reaction was carried out at a rill reaction temperature of 150°C,
A hydrogenated polybutadiene glycol having an iodine value of 9 is synthesized.

This hydrogenated polybutadiene glycol 909 and unhydrogenated polybutadiene glycol (1.2
-vinyl 90%, 1,4-trans 10%) 209 and maleic anhydride 459 were reacted at 210°C under a nitrogen stream to obtain an unsaturated polyester.

Next, the above unsaturated polyester 509 was added to ethylene 50f1
An unsaturated polyester resin liquid was obtained. Next, this unsaturated polyester resin liquid 100f! A photocurable resin composition was obtained by adding benzoin ethyl ether 39 to the solution.

This is zinc phosphate treated steel plate (0.8 x 70 x 150 m7
1t) and bar coater ≠ 28 (cured coating thickness, 35-40μ
) and irradiated with light using a 2 kW mercury lamp at an irradiation distance of 10 degrees, and the properties of the cured coating film were measured. The results are shown in Table 1. Example 2 Using the same equipment as in Example 1, unhydrogenated polybutadiene (1,2-
Trans 92.5%, 1,4-trans 7.5%, molecular weight 19501 Iodination 395) 30f1 Hydrogenated product of unhydrogenated polybutadiene having the same carboxyl group 709, maleic anhydride 9.5f1 and ethylene glycol 10.5
9 was reacted at 200° C. for 8 hours in a nitrogen stream to synthesize an unsaturated polyester.

Next, the unsaturated polyester 509 was dissolved in styrene 509 to obtain a resin liquid. The curing characteristics after light irradiation were measured using the same treatment method as in Example 1. The results are shown in Table 1.
Comparative example 1 Epoxy resin Epicoat 8 manufactured by Shell Chemical, USA
28 (epoxy equivalent weight 192) 5709, methacrylic acid 2
609, benzyldimethylamine, 39, and hydroquinone, 0.069, and reacted at 105° C. for 6 hours, the acid value was 2.

Maleic anhydride 159 was added to this and reacted at the same temperature for 3 hours, and the acid value of the reaction product was 13. This resin liquid 6
Styrene 409 was added to 09 to obtain a resin liquid. The curing characteristics after light irradiation were measured using the same treatment method as in Example 1. The results are shown in Table 1. Comparative Example 2 Using the same equipment as in Example 1, maleic anhydride 29.4
9. 134 g of dipropylene glycol and 1 adipic acid
029 was added, and the reaction was carried out at 220°C until the acid value reached 20.

Styrene 409 was added to this reaction product 609 to obtain a resin liquid. Benzoin ethyl ether 39 was added as a photosensitizer to this resin liquid 1009, and the properties of the cured coating film after light irradiation were measured using the same treatment method as in Example 1. The results are shown in Table 1. Comparative Example 3 19 benzoyl peroxide and 0.39 cobalt naphthenate were blended into the unsaturated polyester resin liquid 1009 obtained in Example 1, and a cured coating film of 3 was formed on the same steel plate as in Example 1.
It was applied to a thickness of 5 to 40 μm and cured at 120° C. for 3 hours.

Table 1 shows the properties of the cured coating. The photocurable coating composition according to the present invention has excellent adhesion, electrical insulation, heat resistance, etc., and also has excellent rust prevention properties.

Claims (1)

[Claims] 1 (A) Hydrogenated diene polymer having at least one terminal functional group capable of forming an ester bond 100-5
0% by weight, (B) unhydrogenated diene polymer 0-5 having at least one terminal functional group capable of forming an ester bond;
0% by weight and (C) an unsaturated polyester synthesized from an unsaturated polybasic acid (I), a vinyl monomer (II), and a photosensitizer (III).