JPH0672175B2 - Photocurable composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a photocurable (hereinafter abbreviated as UV cure) resin composition useful in the fields of coating, ink and adhesive.

[Conventional technology and problems]

UV cure is capable of curing coating films, inks, etc. in a short time, is also energy-saving, and has a major contribution to improving productivity, and the coating film obtained by UV curing is hard and has a beautiful appearance. Therefore, it is well known that it is useful and heavily used for woodwork painting, ink for offset printing, and various resists related to electronics.

However, some unsolved problems remain, and elimination of these drawbacks will be useful for further expansion of applications.

The main reason is that since the UV curing is too quick, it is difficult to relax the stress of the cured coating film, and as a result, the adhesion between the substrate and the coating film is significantly impaired.

The use of monofunctional monomers makes this drawback less noticeable, but it is exacerbated, especially when difunctional or higher polyfunctional monomers are used for the dilution.

Unfortunately, existing monofunctional monomers are highly odorous, skin irritating, and susceptible to oxygen even during UV cure. Furthermore, problems such as a decrease in coating film hardness have been pointed out, especially odor and skin irritation,
The deterioration of the coating film properties is a fatal drawback, and it is the current situation that the advantages of using a monofunctional monomer such as improved adhesion and large diluting ability are negated.

The present invention improves on the drawbacks of conventional monofunctional monomers, and even though it is a monofunctional monomer, the photocurable resin using it has almost no odor and is excellent in photocurability as well.
The physical properties of the cured coating film are also significantly improved as compared with the use of conventional monofunctional monomers.

[Means for Solving the Problems]

That is, the present invention provides (1) a polyester having at least one unsaturated bond in one molecule, and (2) an acetoacetyl group containing a (meth) acryloyl group and an acetoacetic acid ester group in one molecule ( Meta)
A photocurable composition comprising the combined use of acrylate and.

The acetoacetyl group-containing (meth) acrylate that shares the acetoacetate group and the (meth) acryloyl group is
Almost eliminates the drawbacks of the monofunctional monomer described above,
It has good photocurability and dilutability to polymers or oligomers.

The acetoacetyl group-containing (meth) acrylate that shares the acetoacetate group and the (meth) acryloyl group is
It is synthesized by acetylacetonating an unsaturated alcohol having a (meth) acryloyl group with diketene.

The methylene bond between the two carbonyls of acetoacetic acid ester is active and easily causes hydrogen abstraction reaction. As well known, acetoacetic acid ester shows 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.

The raw material unsaturated alcohol for synthesizing the acetoacetyl group-containing (meth) acrylate, which is a component of the curable composition of the present invention and which shares an acetoacetate group and a (meth) acryloyl group in one molecule, is , For example, the following types.

2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxyphenyl methacrylate, polyethylene glycol mono (obtained by adding two or more molecules of ethylene oxide to (meth) acrylic acid ( (Meth) acrylate, polypropylene glycol mono (meth) acrylate similarly obtained by adding propylene oxide, and monomers having a terminal hydroxyl group obtained by adding caprolactone to an unsaturated alcohol having a (meth) acryloyl group.

The primary hydroxyl group of the unsaturated alcohol is more easily converted to acetylacetonate, but even if it is secondary, the acetylacetonation proceeds by selecting the conditions.

Another alternative text of the curable composition of the present invention, 1
The polyester having at least one unsaturated bond in the molecule is an α-β unsaturated polybasic acid or an acid anhydride thereof, such as maleic anhydride, fumaric acid, itaconic acid, or the like, which is a saturated or unsaturated polybasic acid. It is an unsaturated alkyd obtained by esterifying with a polyhydric alcohol, with or without (or its acid anhydride).

Examples of the saturated or unsaturated polybasic acid or its anhydride include the following types.

Phthalic anhydride, isophthalic acid, terephthalic acid, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, succinic acid, adipic acid, sebacic acid, etc.

Glycol is mainly selected as the polyhydric alcohol, and the use of trivalent or higher is special.

Among them are ethylene glycol, propylene glycol, butanediol 1,3, butanediol 1,4, neopentyl glycol, diethylene glycol, dipropylene glycol, 2,2-diethylpropanediol 1,2.
3. Hydrogenated bisphenol A, bisphenol A ethylene oxide adduct, bisphenol A propylene oxide adduct, trimethylolpropane, etc.

The ratio of unsaturated alkyd and acetoacetyl monomer used is 5% by weight to 80% by weight, preferably 10% by weight to 70% by weight.
It is the following.

When the proportion of the acetoacetyl monomer used is low, the viscosity of the mixed system tends to be too high, and when the proportion of the acetoacetyl monomer used is too high, the meaning of using the unsaturated alkyd together is lost.

If necessary, at least one of the components may be used in combination with a copolymerizable monomer.

The UV curable composition according to the present invention optionally comprises
As a matter of course, a reinforcing agent, a filler, a colorant, a release agent, a thermoplastic polymer and the like can be used in combination if necessary.

Next, the present invention will be described in more detail with reference to examples.

Reference Example 1 Acetoacetyl monomer (a); Synthesis of 2-acetoacetylethyl methacrylate After charging 650 g (5 mol) of 2-hydroxyethyl methacrylate, 5 g of dibutyltin dilaurate and 0.5 g of parabenzoquinone into an autoclave, N ₂ substitution was performed. 3.0 → 0.2 kg
It was performed 3 times / cm ² .

Then, while stirring, 462 g (5.5 mol) of diketene was charged into the dropping funnel, and a pressure of about 5 kg / cm ² was applied with N ₂ , and the mixture was added dropwise to the autoclave.

While dripping, the temperature is raised by heat generation and the reaction temperature is about 60 ° C.
The mixture was dropped and reacted for a time.

After the dropping, reduce the pressure to 0.7 kg / cm ² and hold for 60 minutes at 60 ° C.
To complete the reaction.

The generated 2-acetoacetylethyl methacrylate is
It was a light yellowish brown liquid with a purity of about 95%.

Example 1 Synthesis of unsaturated alkyd (A) Propylene glycol 16 was placed in a one-separable flask equipped with a stirrer, a fractionating condenser, a thermometer, and a gas introduction tube.
Charge 7 g, ethylene glycol 138 g, and isophthalic acid 250 g, and esterify to 180-190 ° C in a nitrogen gas stream to obtain an acid value of 2
After setting to 1.4, add adipic acid 73g, fumaric acid 232g,
Further, the esterification proceeds at 190 to 205 ° C and the final acid value becomes 3
Then, 0.15 g of hydroquinone was added, and the mixture was poured into a metal vat and cooled.

A pale tan, slightly soft pine resin-like unsaturated alkyd (A) was obtained.

Production of Photocurable Resin [I] 2-Acetoacetoylethyl acrylate obtained in Reference Example in 50 parts (weight, hereinafter the same) of unsaturated alkyd (A)
A photocurable resin [I] was obtained by roll-kneading 50 parts, 2 parts of DALOCURE # 1173 manufactured by Merck & Co., 10 ppm of a silicon defoaming agent and 1 part of EROSIL.

There was no odor peculiar to the functional acrylate. After coating to a thickness of 100 μm on a bonderite steel plate, 10 cm below the lamp of an ultraviolet irradiation device with an output of 2 KW was passed at a speed of 1 m / min.

Curing occurred in one pass.

The hardness of the obtained coating film is 2H, and the glutinous eye adhesion test is 100/10
It was 0.

Example 2 Synthesis of unsaturated alkyd (B) Butanediol 1,3 was added to a one-separable flask equipped with a stirrer, a fractionating condenser, a thermometer, and a gas introduction tube.
g, butanediol 1,4 133g, isophthalic acid 348g, esterified in a nitrogen stream at 190-200 ° C to give an acid value of 18.5, then itaconic acid 118g, further esterified at 180-190 ° C. Hydroquinone 0. at an acid value of 44.1.
15 g was added, poured into a metal round can, and cooled.

Light yellow-brown semi-solid syrup-like unsaturated alkyd (B)
was gotten.

Acetoacetyl monomer (b): Synthesis of acetylacetonate of caprolactone-modified acrylate ester 230 g of Praxel FA-1 (assuming 1 mol of caprolactone added to 2-hydroxyethyl acrylate) of Daicel Chemical Industries, Ltd. was charged in an autoclave, After performing nitrogen replacement 3 times, while stirring, add about 5 kg / cm ² from the dropping funnel.
170 g of diketene are added dropwise under pressure.

The temperature rises with the reaction, so cool it if necessary to keep it at 55-60 ° C.

After reacting for 2 hours, aging for another 30 minutes and finally 10 Torr
The unreacted material was removed under reduced pressure.

Gas chromatographic analysis showed that almost all raw materials were Praxel FA-1
A similar distribution was observed, and the presence of free hydroxyl group was not confirmed by infrared analysis. Yellowish brown oil plaque
FA-1 acetylacetonate was obtained.

This was designated as acetoacetyl monomer (b).

Production of photocurable resin [II] Unsaturated alkyd (B) 50 parts by weight Acetoacetyl monomer (b) 50 parts by weight Phenoxyethyl acrylate 30 parts by weight Saturated polyester [Chemit R-188 manufactured by Toray Industries, Inc.] 1
0 parts by weight Darocur # 1173 3 parts by weight Saturated polyester is added as a phenoxyethyl acrylate solution.

On a polyethylene terephthalate film having a thickness of 125 μm, a photocurable resin [II] was applied in a thickness of 30 μm and photocured under the same conditions as in Example 1.

The hardness of the cured coating film was F, and the goggles adhesion test was 100/100.

Separately, a photo-curable resin [II] was coated on a bonderite steel plate, and a polyethylene-terephthalate film having a thickness of 50 µ was adhered thereto, excess resin was removed, and a coating film thickness of about 30 µ was obtained, and photo-curing was similarly performed.

The adhesive strength due to 180 ° peeling was 4 kg / in or more, and the film was broken.

Example 3 Synthesis of unsaturated alkyd (C) In a one-separable flask equipped with a stirrer, a fractionating condenser, a thermometer, and a gas introduction tube, g of bisphenol A ethylene oxide adduct (addition product of ethylene oxide 1 mol) and anhydrous maleic acid were added. After acid g was charged and esterified in a nitrogen gas stream at 210 to 215 ° C. to an acid value of 38.6, hydroquinone g was added and poured into a metal vat and cooled.

An unsaturated alkyd (C) having a yellowish brown color and a melting point of about 80 ° C. was obtained.

Curable ink [III] A photocurable ink was produced with the following formulation.

Unsaturated alkyd (C) 40 parts by weight 2-acetoacetylethyl methacrylate 60 parts by weight Polyvinyl butyral [Sekisui Chemical Co., Ltd. S-REC BM
S] 12 parts by weight Talc 50 parts by weight Phthalocyanine green 2 parts by weight Coupling agent (UCC, A-174) 5 parts by weight Acrylic acid 3 parts by weight Erosil 5 parts by weight Irgacure # 651 [Ciba Corporation] 8 parts by weight Electrolytic copper Screen printed to a thickness of about 30μ on foil and output 2KW
10 cm under the UV lamp of 50 cm / min was passed.
Curing occurred in one pass.

The hardness of the obtained coating film is 3H, and the adhesion test is 100/10.
After leaving it on a solder bath at 0 and 260 ° C for 30 seconds, no abnormality such as swelling or peeling was observed.

〔The invention's effect〕

Since the present invention has the composition as described above, it is possible to obtain a cured resin having a high curing rate, a high hardness and a small internal strain.

Claims (1)

[Claims] 1. A polyester having (1) at least one unsaturated bond in one molecule, and (2) an acetoacetyl group containing a (meth) acryloyl group and an acetoacetic ester group in one molecule. Meta)
A photo-curable composition comprising a combination with an acrylate.