KR970004597B1 - Photo-hardening additive - Google Patents

Abstract

A photosensitizer(I) which could be used in UV curable coating composition for improving the abrasion resistance, the yellowing resistance and the scratch resistance was prepared by Michael addition of caprolactone-modified amine and acrylate monomer having more than two double bonds in it. The caprolactone modified amine was prepared by the reaction of primary amine such as decylamine, cyclopropylamine, cyclohexylamine, pentylamine, cyclododecylamine, and ehtylamine and e-caprolactone. In formula I, n is integer 2-4; R is CH2=CR2-CO-O- (R2 is H, methyl); R1 is C1-20 alkyl; X is C3-20 saturated hydrocarbon; Y is -NR1-CO-(CH2)5-OH.

Description

UV curable photosensitizer

The present invention relates to an ultraviolet light sensitizer for improving the curing rate, yellowing resistance, and the like, and more particularly, to a photosensitizer used in an ultraviolet curable coating film composition for improving abrasion resistance, yellowing resistance and scratch resistance.

Conventionally, a heat curing method using heat or a natural curing method used to cure at room temperature has been used since the curing of the paint has a problem that the curing time is fast, but cannot be used for painting a heat-modified product. The method had a problem of late curing time. In order to make up for the shortcomings of the conventional curing method, to cope with more recent environmental regulations, and to improve productivity and energy saving, an ultraviolet curing system using ultraviolet rays has recently been introduced.

UV curing systems have the advantage of simple installation and excellent gloss. In case of using UV curing system, photoinitiator should be used for curing in a short time. Secondary or tertiary amines have been used to increase the curability of photoinitiators used for this purpose. However, when the secondary or tertiary amine is used as the photoinitiator, the curing rate is increased, but there are disadvantages such as severe yellowing.

The object of the present invention is to provide a UV-curable photosensitizer excellent in abrasion resistance and scratching resistance when used in UV-curable paints, yellowing without yellowing to increase the disadvantages.

The object of the present invention described above is achieved by a UV-curable photosensitizer prepared by reacting a caprolactone-modified amine prepared by reacting a primary amine with caprolactone again with an acrylate monomer having two or more double bonds at its ends. do.

The UV-curable photosensitizer of the present invention reacts a primary amine with whipsilon caprolactone to produce an intermediate of caprolactone-modified amines in the form of secondary amines, and then the intermediate is an acrylate having two or more double bonds. The photosensitizer of the present invention, when used in a paint, exhibits a characteristic of fast curing speed and excellent yellowing prevention when used in a paint.

The present invention will be described in detail as follows.

The ultraviolet curable photosensitizer of the present invention is prepared by the reaction of a caprolactone-modified amine of the following general formula (II) with an acrylate monomer having two or more double bonds of the general formula (III): It includes a compound of.

In the general formula, n is an integer of 2 to 4 and R is (Wherein R ² is hydrogen or methyl) R ¹ is an alkyl group having 1 to 20 carbon atoms, X is a saturated hydrocarbon having 3 to 20 carbon atoms and Y is to be.

The photosensitizer of the general formula (I) reacts the caprolactone-modified amine of the general formula (II) with an acrylate monomer having two or more double bonds of the general formula (III) by Michael Addieion. It is made by.

Caprolactone-modified amines represented by the general formula (II) are prepared by the reaction of primary amines with whipsilon caprolactone, and in order to reduce the yellowing shape, it is preferable to use aliphatic primary amines having high reactivity and many alkyl groups. desirable.

As the primary amine having high reactivity and high alkyl group, decyl amine, cyclopropyl amine, cyclohexylamine, cyclopentylamine, pentylamine, cyclo dodecylamine, ethyl amine and the like are used. In addition, the reaction with the primary amine uses a highly reactive whipsilon caprolactone of the general formula (IV).

Such whipsilone caprolactone is a cyclic ester, a colorless liquid state having a molecular weight of 114.4 g, which is rich in reactivity, and can react with acid alcohols, water, and amines to make numerous compounds.

In the present invention, focusing on the fact that whipsilon caprolactone has a large number of alkyl groups is used to denature the amine and finally use the property of preventing yellowing of the coating film by the alkyl group when a photosensitizer is prepared.

Reactive monomers having two or more terminal double bonds in the production of the photosensitizer include butanediol diacrylate, 1.6-hexanediol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethyl All propane trimethacrylate, pentaerythritol triacrylate, etc. are mentioned.

Unlike the amine used in the conventional UV curable paint, the photosensitizer according to the present invention improves the curing rate participating in the reaction during the curing reaction by ultraviolet rays, so that the curing rate is fast and there is no yellowing shape.

There are two types of curing mechanisms in the case of using the photosensitizer of the present invention. The sensitizer of the present invention is preferably used in the case of using an Norrish type II initiator. In this case, the curing mechanism may be the case where the double bond at the end of the photosensitizer becomes a single bond by the initiator, and may act as an initiator by forming a radical by drawing hydrogen by acting as a tertiary amine (Hydrogen Abstract). .

Since the photosensitizer of the present invention includes a double bond in the structure, it not only promotes the curing reaction by the photoinitiator, but also the curing reaction by the tertiary amine itself, thereby reducing the yellowing phenomenon since the alkyl group is present.

Caprolactone-modified amine of the general formula (II) is prepared by reacting the molar ratio of aliphatic primary amine and whipsilon caprolactone in a ratio of 1.1: 1-1.5: 1, which is preferable in consideration of curing and yellowing properties, etc. The ratio is 1.2: 1.

In the preparation of the photosensitizer of general formula (I), the molar ratio of the caprolactone-modified amine and the monomer having two or more heavy bonds at the terminal is 1: 2-1: 4, and the Michael addition reaction is carried out in the presence of a strong base catalyst. To make it.

At this time, sodium hydroxide, potassium hydroxide and the like can be used. When the photosensitizer according to the present invention is added to the paint, yellowing resistance is increased and the curing speed is increased.

The effect of the ultraviolet curable photosensitizer of this invention is demonstrated in detail by the following Example and a comparative example. Unless otherwise specified, "parts" means "parts by weight".

Example 1

592 g of propane triaclate was injected with trimethyl having three double bonds at the end into a four-necked round flask, and a condenser, a stirrer, and a thermometer were installed, and 54.1 g of ethylamine was reacted with 114 g of whipsilone caprolactone at room temperature. 159.2 g of a caprolactone-modified amine was injected into a dropwise funnel, and sodium hydroxide was used as a catalyst. After stirring at 40 ° C., the progress and end of the reaction were determined by measuring the amine value and infrared instrument analysis. Water was added and azeotropically under 13 mmHg pressure to remove unreacted amine in the reaction solution to obtain a photosensitizer.

Example 2

According to the method of Example 1, 213 g of caprolactone-modified amine prepared by reacting 109 g of hexyl amine with 114 g of whipsilone caprolactone were reacted with 339.5 g of 1.6-hexanediol diacrylate to prepare a photosensitizer.

Example 3

According to the method of Example 1, a photosensitizer was prepared by reacting 200 g of caprolactone-modified amine prepared by reacting cyclopentyl amine 103.2 g with 114 g of whipsilone caprolactone with 704 g of pentaerythritol tetraacrylate.

Formulation Example 1

444 parts of "Ebecryl-284" of the urethane acrylate 200 parts of 1.6-hexanediol diacrylate, 200 parts of neopentyl glycol diacrylate, 56 parts of trimethyl propane triacrylate, Ciba-Geigy Co., Ltd. 40 parts of "Darocure 1173", 10 parts of "Ecrycryl 350" of Yushivis, a silicone acrylate, and 50 parts of the photosensitizer prepared in Example 1 were stirred at 40 ° C., and the UV curable varnish having a viscosity of 700 cps at 25 ° C. Was prepared.

Physical property test results are shown in Table I.

Formulation Example 2

According to the composition of Formulation Example 1, but using 50 parts of the photosensitizer of Example 2 to prepare an ultraviolet curable varnish.

Formulation Example 3

According to the composition of Formulation Example 1, but using 50 parts of the photosensitizer of Example 3 to prepare an ultraviolet curable varnish.

In order to compare the effects of the photosensitizers according to the present invention, Comparative Examples 1 and 2 are described. Triethanolamine was used instead of the photosensitizer, and Comparative Example 2 did not use the photosensitizer and the amine.

Comparative Example 1

According to the composition of Formulation Example 1, but instead of the photosensitizer of the present invention to prepare a varnish using 50 parts of triethanol amine.

Comparative Example 2

According to the composition of Formulation Example 1, a varnish was prepared without using a photosensitizer and an amine.

TABLE 1

* Curing condition: High pressure mercury lamp 80W / cm, 2 lamp irradiation distance 10cm

* Dry film thickness: 10 ~ 15㎛

* Painting method: paint with vinyl coating on bar plate

* 1 yellowing: visual observation after 10 minutes of curing with curing energy 1000mj / cm ²

* 2 Curing Energy: Use International Light's Light Bug (IL390)

* 3 Abrasion Resistance: Use of Teledin Taber's Model 505

* 4 scratch resistance: using the Wakey's Dur-O tester

* 5 Adhesion: measured according to JIS 0202 (cross cut)

(●: Good, ▲: Normal, ×: Poor)

Compared with Comparative Example 1 using the amine, the present invention shows that the curing rate is similar but excellent in yellowing resistance, and the curing rate is similar, but the curing rate and the yellowing resistance are excellent compared to Comparative Example 2.

Claims (5)

An ultraviolet curable photosensitizer for use in the ultraviolet curable coating film composition containing the caprolactone modified amine acrylate of general formula (I). R in the general formula (Wherein R ² is hydrogen or methyl) X is a saturated hydrocarbon having 3 to 20 carbon atoms and Y is (Wherein R ¹ is an alkyl group having 1 to 20 carbon atoms) n is an integer of 2-4. The caprolactone-modified amine of formula (II) is reacted with an acrylic ester monomer of formula (III) having two or more double bonds of wheat tips in the presence of a strong base to form a UV-curable photosensitizer. Process for producing caprolactone modified amine acrylate. In the general formula, X, R, n have the meaning in claim 1. The method according to claim 2, wherein the caprolactone-modified amine of formula (II) is prepared by reacting whipsilon caprolactone with an aliphatic primary amine having many alkyl groups. 4. The process of claim 3 wherein the aliphatic primary amine is selected from decylamine, cyclopropylamine, cyclohexylamine, cyclopentylamine, pentylamine, cyclo dodecylamine and ethyl amine. The method of claim 2 wherein the acrylic ester monomers are butanediol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate and 1.6-hexanediol Characterized in that it is selected from diacrylates.