JPH0678410B2 - Photocurable composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a composition comprising a photocurable vinyl ester resin and a diluent thereof, which are useful in the fields of paints, inks and adhesives.

[Conventional technology and problems]

It is well known that a vinyl ester resin is used for photo-curing, and it is widely used mainly in solder resists and constitutes one of the photo-curing utilization techniques. However, some unsolved problems have been pointed out, and elimination of these drawbacks is useful for further expansion of applications.

The main reason is that since the photo-curing is too fast, the stress relaxation during the curing is not performed and, as a result, the adhesiveness to the substrate is greatly impaired.

In particular, it becomes remarkable when a difunctional or higher functional monomer is used as a diluent.

However, the odor of monofunctional acrylate type monomer
Problems such as insufficient curability in air and deterioration of physical properties of coating films have been pointed out. In particular, odor and deterioration of physical properties of cured coating films are fatal defects, and monofunctional acrylates should be used. The present situation is that the effect of improving the adhesiveness due to the body is completely canceled out.

The present invention improves on the drawbacks of conventional monofunctional monomers,
Despite being a monofunctional acrylate, it has almost no odor, and it is also excellent in photocurability, providing a photocurable composition in which the physical properties of the cured coating are significantly improved compared to conventional monofunctional monomers. To do.

[Means for Solving the Problems]

That is, the present invention provides (a) a vinyl ester resin having one or more (meth) acryloyl groups in one molecule, and (b) an acetoacetate sharing a (meth) acryloyl group and an acetoacetic acid ester group in one molecule. Contains acetyl groups (meta)
The present invention provides a photocurable composition, which is used in combination with an acrylate.

(Vinyl ester resin) The vinyl ester resin which is one component of the composition of the present invention is roughly classified and synthesized by the following two methods.

(A) Epoxy resin having two or more epoxy groups is reacted with (meth) acrylic acid.

(B) Polyhydric phenols or novolacs are reacted with glycidyl methacrylate.

Modification with polybasic acids and polyhydric phenols is also possible.

Generally, from the viewpoint of cost, the reaction product resin of (a) epoxy resin and (meth) acrylic acid is treated as a vinyl ester resin.

The epoxy resin used as the raw material for the vinyl ester resin does not need to be particularly limited, but in general, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether (all of which include polymer homologs), bisphenol S diglycidyl ether, novolac glycidyl. Examples thereof include glycidyl ether type epoxy resins such as ethers, so-called alicyclic epoxy resins obtained by oxidizing unsaturated cyclic compounds, and glycidyl ester type epoxy resins.

(Acetoacetyl group-containing (meth) acrylate that shares a (meth) acryloyl group and an acetoacetic acid ester group in one molecule) A (meth) acryloyl group and an acetoacetic acid ester in one molecule used in the composition of the present invention The acetoacetyl group-containing (meth) acylate that shares a group with each other is synthesized by acetylacetonating an unsaturated alcohol having a (meth) acryloyl group with diketene.

The methylene bond between the two carbonyls of the acetoacetic ester is active and readily causes a hydrogen abstraction reaction. Also, as is well known, acetoacetic acid esters show typical keto-enol tautomerism, It may also be related to photocuring.

Although the reason is not clear, the polymer having an acetoacetic acid ester group in its side chain becomes insoluble in the solvent by heating.

As a raw material unsaturated alcohol for the synthesis of an acetoacetyl group-containing (meth) acrylate, which is a component of the photocurable composition of the present invention and which shares a (meth) acryloyl group and an acetoacetic ester group in one molecule Is the general formula [Wherein R represents hydrogen or a methyl group, A represents a hydrocarbon group having or not having a divalent ether or ester bond], but practically, A is at the position of 2 carbon atoms. Unsaturated alcohols with hydroxyl groups are preferred. Typical examples thereof include the following types.

2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, and 2-hydroxyphenyl methacrylate are preferred, and polyhydric alcohol is reacted with (meth) acrylic acid. It is also possible to use monomers having a terminal hydroxyl group obtained by adding 1 to 20, preferably 1 to 5 alkylene oxide or caprolactone to an unsaturated alcohol sharing a (meth) acryloyl group and a hydroxyl group.

The terminal hydroxyl group is easily acetylacetonated when primary, but the secondary type is also acetylacetonated by selecting conditions.

(Composition) The use ratio of the vinyl ester resin and the acetoacetyl group-containing (meth) acrylate varies depending on the use and need not be particularly limited, but generally speaking, the vinyl ester resin 90 to 10% by weight ( The weight is omitted hereinafter) and 10 to 90% of acetoacetyl group-containing (meth) acrylate, but a suitable range is 80 to 20% of vinyl ester resin and 20 to 80% of acetoacetyl group-containing (meth) acrylate.

For example, when polymers are used together for modification, even if the content of the acetoacetyl group-containing (meth) acrylate is high, it becomes sufficiently practical.

In addition, commonly used monomers can be used in combination as required.

When photocuring the composition according to the present invention, it is necessary to use an initiator that absorbs light energy to generate radicals.

As the initiator, various types that are generally used, for example, various types such as benzyl ketals, acetophenone derivatives, benzoin ethers, and a combination system of thioxanthone and amine can be used.

If electron beam irradiation is used, no initiator is necessary.

The composition according to the present invention, if necessary, a filler, a reinforcing material,
Of course, a colorant, a release agent, an antifoaming agent, a soluble polymer and the like can be used in combination.

Next, the present invention will be described in more detail with reference to examples. In the examples, “parts” means “parts by weight” unless otherwise specified.

Example 1 Synthesis of vinyl ester resin (A) In a one-separable flask equipped with a stirrer, a reflux condenser, and a thermometer, 360 g of bisphenol diglycidyl ether type epoxy resin having an epoxy equivalent of 176 and acrylic acid were used.
144 g, trimethylbenzyl ammonium chloride 2 g,
Hydroquinone (0.25 g) was charged and reacted at a temperature of 125 to 130 ° C. for 3 hours to obtain a vinyl ester resin having an acid value of 8.7.

Photocurable resin composition (I) The temperature was lowered to 100 ° C., and 220 g of 2-acetoacetylethyl acrylate was added thereto to obtain a curable resin composition (I) having a Hazen color number of 450 and a viscosity of 3.9 poise.

Physical Properties of Photocurable Resin 100 parts of the curable resin composition (I), 2 parts of "Darocure # 1173" of Merck & Co. as a photoinitiator, and 3 parts of Elosil were uniformly kneaded with a roll, and 100 µ of this on a bonderite steel plate. It was painted thick and passed 10 cm under a UV lamp with an output of 2 KW at a speed of 2 m / min. Curing was completed in one pass, and a cured coating film with a pencil hardness of 3H and coating film adhesion of 100/100 was obtained. In addition, no peculiar odor observed when using a monofunctional acrylate monomer was observed.

Comparative Example 2 Instead of 2-acetoacetylethyl acrylate, 2
A type in which the same weight of ethylhexyl acrylate was added was designated as a curable resin composition (II).

In the same manner, paint the photo-curable resin with Darocur # 1173 and EROZIL on the bonderite steel plate, 10 cm below the lamp.
When it was passed at 2 m / min, some tack remained on the surface once, and irradiation was repeated three times.

A large difference was observed in the coating film physical properties and curability at pencil hardnesses B to F and coating film adhesion of 68/100.

Example 2 Synthesis of vinyl ester resin composition (B) In a two-separable flask equipped with a stirrer, a reflux condenser, and a thermometer, 500 DEN-438 (epoxy equivalent 180) of Dow Chemical Co. was used as a novolac type epoxy resin.
g, methacrylic acid 215 g, 2-methylimidazole 7 g,
0.35 g of hydroquinone was charged and reacted at 130 to 135 ° C. for 3 hours to obtain a vinyl ester resin (B) having an acid value of 14.7.

Photocurable resin composition (III) 380 g of 2-acetoacetylethyl methacrylate
To obtain a photocurable resin composition (III) having a viscosity of 54 poise and a Gardner color number of 4 to 5. This was used to produce a solder resist ink with the following composition.

Photocurable resin composition (III) 100 parts Thermoplastic polyester 20 parts (phenoxyethyl acrylate 50% solution Tg of polyester ≈ 28 ° C ethylene glycol-diethylene glycol-isophthalic acid-terephthalic acid) Talc 50 parts Phthalocyanine green 2 parts Defoamer 10ppm Darocure # 1173 3 parts This is coated on the surface of electrolytic copper foil with a thickness of 35μ to a thickness of 30μ, 2K
A 10 cm portion of the W irradiation UV irradiation device was passed at 50 cm / min.

The hardness of the cured coating film is 3H, and the adhesion test is 100/100, 260
A ℃ solder bath immersion test showed heat resistance of 30 seconds or more.

Example 3 Synthesis of vinyl ester resin (C) In a one-separable flask equipped with a stirrer, a reflux condenser, and a thermometer, 280 g of Union Carbite's ERL-4221 and 73 adipic acid were used as a cycloaliphatic epoxy resin.
When g, 72 g of acrylic acid, 2 g of triphenylphosphine and 0.2 g of hydroquinone were charged and reacted at 120 to 125 ° C. for 4 hours, the acid value became 11.3, so 225 g of 2-acetoacetyl acrylate was added and vinyl ester resin ( C)
Was obtained with a Hazen color number of 350 and a viscosity of 20.9 poise.

To 100 parts by weight of vinyl ester resin (C), 10 parts by weight of phenoloxyethyl acrylate and 2.5 parts of Darocur # 1173 are used.
In addition to parts by weight, it was coated on a Bonderite steel plate to a thickness of 50 μm, and passed through a 10 cm under an ultraviolet lamp with an output of 2 kw at 2 m / min. Curing was done in one pass.

The hardness of the obtained coating film is F to H, and the eye contact test is 10
It was 0/100, and peeling of the coating film did not occur even when the steel sheet was bent 90 degrees.

〔The invention's effect〕

Since the present invention is configured as described above, a photocurable resin composition having a high curing rate is provided, and a cured product having excellent hardness and heat resistance can be obtained.

Claims (1)

[Claims] 1. A vinyl ester resin having (a) one or more (meth) acryloyl groups in one molecule, and (b) an aceto that shares a (meth) acryloyl group and an acetoacetic acid ester group in one molecule. Contains acetyl groups (meta)
A photocurable composition, which is used in combination with an acrylate.