JPS5928567B2 - UV curable composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ultraviolet curable composition containing an ester of 0-benzoylbenzoic acid and an alcohol having an unsaturated double bond as a polymerization initiator.

Recently, in the printing and coating industries, demand for ultraviolet curable inks and coatings has been rapidly increasing for the purpose of eliminating air pollution.

Such compositions include prepolymers, diluents, polymerization initiators, pigments, and the like. Among these, the polymerization initiator is an important material that affects the curing speed of the composition. Conventionally, carbonyl compounds such as benzophenone, benzyl, benzyl ketal, benzoin ether, and acetophenone have been mainly used as polymerization initiators, but benzophenone is particularly superior in terms of curing speed and is inexpensive. A considerable amount is used.

However, in general, the polymerization initiator that contributes to the curing reaction is only a part of the polymerization initiator contained in the system, and the remaining part remains unreacted in the cured film. .

Therefore, the unreacted polymerization initiator not only has a negative effect on the base material, but also has a negative effect on adhesive strength and film performance. Furthermore, since the surface is touched by people, it is not desirable from the standpoint of safety and health. In the case of benzophenone, most of it remains unreacted in the cured film, and the proportion of the polymerization initiator eluted when the film is immersed in a solvent is very high.

As a result of intensive study on this point, the present inventors found that an ester compound of 0-benzoylbenzoic acid, which is a derivative of benzophenone, and an alcohol having an unsaturated double bond, that is, 0=C-0-R ・〇1〇 The above-mentioned drawbacks could be solved by using as a polymerization initiator.

R in the above formula represents an alkenyl group having 3 to 10 carbon atoms or an alkenyl group having 3 to 10 carbon atoms substituted with 1 to 2 phenyl groups. Typical examples of such compounds include esters of 0-benzoylbenzoic acid and allyl alcohol.

Furthermore, by using such compounds, it was also possible to solve the problem of bad odor, which is one of the drawbacks of benzophenone.

The polymerization initiator used in the present invention is 1 to 1 to 1 to 1 per prepolymer.
It is appropriate to use about 5% by weight.

The resulting film has an extremely small proportion of the polymerization initiator eluted by the solvent compared to the case of benzophenone. This means that in the case of benzophenones, the carbonyl group is involved in radical generation, but by introducing an unsaturated double bond, it can function as a crosslinking agent in addition to a polymerization initiator. This means that the elution rate of the polymerization initiator into the solvent has become low. j (Ester of 0-benzoylbenzoic acid and crotyl alcohol Ester of 0-benzoylbenzoic acid and cinnamyl alcohol) The curing rate and elution rate were measured using the above formulation, and the results shown in Table 1 were obtained. .

Each test method was as follows.

(1) Curing speed Each formulation composition was coated on a polyester film using an RI tester (film thickness 12 μm), and irradiated with an ultraviolet curing device (trade name: UQURE UV4OOO (manufactured by Ushio Electric Co., Ltd.)) to cure it. Evaluation was based on the number of passes required.

*Irradiation conditions Run 7 specific power 120W/CTLl conveyor speed 8.8m/Mm (2) Elution rate Each formulation composition was applied to aluminum foil using an applicator (film thickness 80μ), and the same conditions as above. After curing the film sufficiently, a certain amount of the film was peeled off from the aluminum foil, immersed in acetone at room temperature for 20 hours, and the amount of polymerization initiator eluted was determined using thin layer chromatography. The elution rate for the polymerization initiator was determined.

The results shown in Table 2 were obtained using the same test method as in Example 1.

The results shown in Table 3 were obtained using the same test method as in Example 1.

Claims (1)

[Claims] ▲ Numerical formulas, chemical formulas, tables, etc. ) An ultraviolet curable composition containing, as a polymerization initiator, an ester compound of O-benzoylbenzoic acid represented by the above formula and an alcohol having an unsaturated double bond.