JPH03188117A - Ultraviolet-curable composition - Google Patents

Abstract

PURPOSE:To prepare the title compsn. capable of curing quickly even in the presence of oxygen and useful for a coating material, adhesive, sealant, etc., by compounding, as the main component, a compd. having a backbone structure wherein a (meth)acrylate contg. a hydroxyl group is joined to tetrahydrophthalic acid through ester groups. CONSTITUTION:The title compsn. is prepared by compounding: 100 pts.wt. tetrahydrophthalic ester of a (meth)acrylate contg. at least one hydroxyl group (e.g. bisphenol A monoacrylate); 1-5 pts.wt. photopolymn. initiator (e.g. dimethyl benzil ketal); 1-2 pts.wt. org. peroxide (e.g. 1,1-di-t-butylperoxy-3,3,5- trimethylcyclohexane); and 0.1-1.0 pt.wt. curing accelerator comprising a metal soap (e.g. cobalt naphthenate).

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an ultraviolet curable composition containing a compound having a tetrahydrophthalic acid core ester-bonded to a (meth)acrylate having at least one hydroxyl group, and in particular to a coating material. The present invention relates to an ultraviolet curable composition that can be easily cured even in the presence of oxygen in the air and is useful for adhesives, sealants, etc.

Ultraviolet curable resins are widely used as paints, sealants and adhesives. These resins include, for example, acrylic prepolymers, which are unsaturated oligomers with a molecular weight of several hundred to several thousand, having one or more acryloyl or methacryloyl groups, polyfunctional (meth)acrylate monomers, and polyfunctional (meth)acrylate monomers having (meth)acrylate groups. A mixed composition of a monofunctional monomer and a photoinitiator is used, and if necessary, a composition containing polymerizable monomers such as styrene and allyl ester, pigments, fibers, antifoaming agents, etc. is used.

Examples of acrylic prepolymers include epoxy (meth)acrylate which is an ester of an epoxy compound and (meth)acrylate and has water 521, polyester (meth)acrylate whose main chain is polynisdel, polybutadiene (meth)acrylate whose main chain is polybutadiene, There are urethane (meth)acrylates whose main chain is made of urethane resin.

Ultraviolet curable resin compositions composed of these mixed compositions can be cured by ultraviolet irradiation for several seconds to tens of seconds, and are therefore widely used as paints, adhesives, sealants, or photoresists.

However, ultraviolet curing is easily affected by m elements in the air.
When the intensity of ultraviolet rays is low, there is a disadvantage that the resin surface remains uncured and sticky.

In addition, three-dimensional objects, parts containing parts, and parts cabinets with holes inside,
Since the light from the UV irradiation lamp does not reach it, it remains uncured.

Therefore, in recent years, a combination of light and heat curing has been used. The method is to add organic 1M to ultraviolet curable resin.
This method involves adding chemical compounds or adding thermosetting epoxy resin. Precursor uses heat to advance radical polymerization,
The curing mechanism is the same as in the case of light, and if oxygen is present, curing will not proceed. The latter prevents oxygen from entering from the surface by curing the epoxy resin, and then proceeds with radical polymerization. However, the latter has a usable time (
It has shortcomings such as short pot life.

Furthermore, in order to eliminate the influence of M elements, methods such as irradiating ultraviolet rays in nitrogen gas or increasing the energy density of the surface irradiated with ultraviolet rays can be considered, but these methods increase costs and cause deterioration of quality, so these methods are not suitable. do not have.

Means for Solving the Problems The inventors of the present invention have conducted repeated studies to solve these problems, and as a result, have arrived at the present invention.

That is, the present invention has at least one hydroxyl group (
This is an ultraviolet curable resin composition whose main components are a compound having a tetrahydrophthalic acid core bonded to meth)acrylate through an ester bond, a photopolymerization initiator, an organic peroxide, and a metal soap curing agent.

In this specification, (meth)acrylate generally refers to acrylate and methacrylate, and (meth)acryloyl group refers to acryloyl group and methacryloyl group.

The compound having a tetrahydrophthalic acid core ester bonded to a (meth)acrylate having at least one hydroxyl group, which is an important component of the composition of the present invention, may be tetrahydrophthalic acid or tetrahydrophthalic anhydride. (good) and at least one hydroxyl group (
It is a compound in which meth)acrylate is ester bonded, and has both a (meth)acryloyl group and a tetrahydrophthalic acid molecular core within its molecule. The tetradidrophthalic acid compound is preferably tetrahydrophthalic anhydride, methyl tetrahydrophthalic anhydride,
In addition to tetrahydrophthalic acid and methyltetrahydrophthalic acid, endomethylenethitrahydrophthalic acid, endomethylenetetrahydrophthalic anhydride, etc. are also used.

At least one water I! ! The (meth)acrylate having a group is preferably obtained by an ester reaction between (meth)acrylic acid and an alcohol or epoxy compound having two or more hydroxyl groups. These alcohols include diols with two hydroxyl groups in the molecule, such as ethylene glycol, propylene glycol, tetramethylene glycol, polyethylene glycol, 1,6-hexanediol, bisphenol A1 bisphenol S1 hydrogenated bisphenol A1 bisphenol F1. trihydric alcohols such as glycerin and trimethylolpropane, and tetrahydric alcohols such as pentaerythritol. Examples of the epoxy compound include bisphenol A epoxy resin, bisphenol F epoxy resin, alicyclic epoxy resin, ethylene oxide, and glycidol. In addition,
Also included are compounds that have an intervening ester bond or urethane bond and a terminal hydroxyl group or epoxy group.

As these (meth)acrylates, the following are preferably used. Ester compounds with alcohol include hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (
1@ such as meth)acrylate, polyethylene glycol mono(meth)acrylate, bisphenol A mono(meth)acrylate, bisphenol S mono(meth)acrylate, bisphenol F mono(meth)acrylate, hydrogenated bisphenol A mono(meth)acrylate, etc. There are mono-, di-, or triacrylates having one or two hydroxyl groups, such as (meth)acrylate, glycerin (meth)acrylate, trimethylolpropane (meth)acrylate, and pentaerythritol (meth)acrylate, which have hydroxyl groups. Ester compounds with epoxy compounds include epoxy (meth)acrylates such as bisphenol A epoxy resins.
Examples include acrylates, and (meth)acrylates of urethane prepolymers having hydroxyl groups at the terminals and polyvinyl brevolomers.

The compound of the present invention having a tetrahydrophthalic acid core ester-bonded with a (meth)acrylate having at least one hydroxyl group has at least one tetrahydrophthalic acid or tetrahydrophthalic anhydride compound as described above.
It is obtained by subjecting (meth)acrylate having hydroxyl groups to an esterification reaction. All of the water mu of the (meth)acrylate having at least one hydroxyl group may be esterified, or only the hydroxyl group at -.

As the photopolymerization initiator in the present invention, benzoin, benzoin ethyl ether, benzophenone, dimethylbenzyl ketal, 2-ethylanthraquinone, hydroxycyclohegylphenyl ketone, diphenyl sulfide, etc. are used alone or in combination.

Preferred organic peroxides include 1,1-di-tert-butyl peroxybenzoate, 3,3,5-trimethylcyclohexone, benzoyl peroxide, methyl ethyl ketone peroxide, tert-butyl peroxybenzoate, and dicumyl peroxide. etc. are used.

As the metal soap curing accelerator, metal salts of naphthenic acids, such as cobalt, manganese, copper, barium, zinc, and zirconium naphthenates, are preferably used.

In the composition of the present invention, the amount used is the compound 1 having a tetrahydrophthalic acid core ester-bonded with a (meth)acrylate having at least one water M group.
The ratio of 1 to 5 polymerization parts of the photopolymerization initiator, 1 to 2,000 parts of the organic peroxide, and 0.1 to 1.0 parts by weight of the curing accelerator to 00 parts by weight is preferable.

Furthermore, polyfunctional (meth)acrylates such as trimethylolpropane tri(meth)acrylate, hexanediol di(meth)acrylate, and epoxy(meth)acrylate, and monofunctional superacrylates such as styrene and methyl methacrylate.
may be added as necessary, but the compound having a tetrahydrophthalic acid core should account for at least 10% by weight, preferably 30% by weight or more, and more preferably 50% by weight or more of the entire polymerizable compound. is necessary.

In addition, various additives such as fillers,
Pigments, antifoaming agents, flame retardants, etc. can be added.

The ultraviolet curable composition of the present invention containing the compound having a tetrahydrophthalic acid core is easily polymerized and cured by ultraviolet irradiation or heating, even in the presence of wood in the air. Although the reason for this is not clear, it is presumed that oxygen is consumed due to generation of hydroperoxide due to air oxidation and oxygen crosslinking. The compositions of the present invention can be cured by both ultraviolet and thermal energy. Therefore, it is possible to sufficiently harden the surface only by irradiating ultraviolet rays, and it is also possible to harden the surface tack-free by irradiating weak ultraviolet rays and heating the surface while it remains sticky.

Ultraviolet light with a wavelength of 200 to 400 mμ is usually used as a light source, and metal halide lamps, xenon lamps, and high-pressure mercury lamps are used as light sources, and the curing time is from several seconds to several minutes. - Irradiation at room temperature during boat fishing is possible. When using the UV-curable compositions of the present invention, displacement with inert gas is unnecessary. When heat curing is involved, the temperature is preferably 100 to 130°C for 0.5 to 1 hour.

The ultraviolet curable composition of the present invention contains a special polymerizable curable compound such as a compound having a tetrahydrophthalic acid core ester bonded to a (meth)acrylate having at least one hydroxyl group. Even surfaces where oxygen exists in the air can be easily cured by ultraviolet rays, making replacement with an inert gas unnecessary. In addition, since it contains organic peroxides, heating is also used to promote sufficient curing when painting three-dimensional objects that are difficult to irradiate with sufficient UV rays, or when painting the inside of objects that cannot be irradiated with UV rays. be able to.

Therefore, it can be completely cured from the surface to the inside, and can be used for excellent coatings, adhesives, sealants, etc. that have a tack-free surface.

Example 1 Evo 4 diacrylate (epoxy equivalent of bisphenol Δ type 19
To this, 62 g of methyltetrahydrophthalic anhydride (0.3 molar equivalent to the water IGI of the epoxy acrylate) was added, and the mixture was heated at 80°C for 50 g. The reaction mixture was stirred for hours. The following composition was obtained using this reaction product.

Reaction product 131g trimethylolpropane triacrylate 20g styrene
309 Trigonox 29B-
752 g (1,1-di-t-butylbaroxy 3.3.5-trimethylcyclohexane, manufactured by Kayaku Nouri) Cobalt naphthenate <1.007 g Benzyl dimethyl ketal 2 g Large mouth 0λ A reactor similar to Example 1 was used. 200g of hexamethylene diglycidyl ether diacrylate was added to it, and 8282g of tetrahydrophthalic anhydride (based on hydroxyl groups,
．． 5 mol equivalent (m) was added thereto, and the mixture was stirred at 80° C. for 5 hours to react. The following composition was obtained using this reaction product.

Reaction product 140g hexanediol diacrylate 20g styrene
30g0g Tribonox 293f
29 Cobalt naphthenate 0
．． 001 g benzoin ethyl ether 2 g
Using the same reactor as in Example 1, take 100 CJ of 2-hydroxydiethyl methacrylate and add 115 g of methyltetrahydrophthalanhydride R (068
molar equivalent) was added thereto, and the mixture was stirred at 80° C. for 5 hours to react. The following composition was obtained using this reaction product.

Reaction product 200gR-13
0 (Epoxy acrylate manufactured by Nippon Herbal Medicine tIl) 10 JJ hexanediol diacrylate 50 g 0 g Tribonox 29-75 29 Cobalt puftenate 0.0019 Benzyl dimethyl ketal 2 g Comparative Example 1 The following composition was prepared.

Evogyacrylate (same as Example 1) 00g Trimethylolpropane triacrylate 09 Styrene 309 Trigonox 29B -752g Cobalt puftenate o, ooi
g Benzyl dimethyl ketal 2 g Example 4 Above, a surface hardening test was conducted for Example 1.2.3 and a comparative example.

Each formulation is applied to a thickness of 200 μm on a glass plate using a bar coater in air.

Ultraviolet rays are irradiated for 1 second using an ultraviolet irradiator equipped with a metal halide lamp with an output of 4Kw and 80W/α. With this irradiation, the surfaces of all the formulations were not sufficiently cured and remained sticky. This was heated at 110° C. for 30 minutes and the cured state was examined using a finger touch test. The finger touch test involves touching the hardened sample surface with a finger that has been cleaned with acetone.
This was done by checking the presence or absence of stickiness.

These results are shown in Table 1.

Table 1 In addition, in the comparative example, in the case of 1 second of ultraviolet irradiation, 5
Even after heating for a long time, the stickiness on the surface could not be removed.

t:;p1 person b rJ’l! , 1: Chin 2 Mountain Takeshi

Claims (1)

[Claims] An ultraviolet curable composition containing as main components a compound having a tetrahydrophthalic acid core bonded to a (meth)acrylate having at least one hydroxyl group, a photopolymerization initiator, an organic peroxide, and a metal soap curing accelerator. thing.