JPH10251226A - Benzophenone skeleton-containing peroxide, its production and use - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a new compound useful as a radical generating agent and a polymerization initiator, especially a photopolymerization initiator. SOLUTION: This compound is shown by formula I (R<1> is a 4-8C tertiary alkyl, a 9-12C aromatic substituted tertiary alkyl; R<2> is a 1-4C alkylene) such as 4-(t-butylperoxycarbonylmethyl)benzophenone. The compound of formula I is obtained, for example, by reacting 1mol of a benzophenone skeleton- containing chloroformate of formula II [4-(chloroformyl methyl)benzophenone, etc.] with 0.5-3.0mol of a tertiary hydroperoxide (t-butylhydroperoxide, t- amylhydroperoxide, etc.) in an organic solvent (benzene) in the presence of 0.5-5mol of a base (sodium hydroxide) at -10 to 60 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel benzophenone skeleton-containing peroxide which is used as a radical generator, a polymerization initiator, particularly a photopolymerization initiator or a photocuring agent, and a method for producing the peroxide.

[0002]

2. Description of the Related Art Polymerization and curing methods for photopolymerizing or photocuring a photopolymerizable (photocurable) monomer and a photopolymerizable (photocurable) resin composition are lower in temperature than thermal polymerization, thermosetting and oxidative curing methods. It has many advantages such as quick curing, improved productivity, energy saving and no pollution. In addition, since selective curing is also possible, printing inks, paints, adhesives, resin letterpress,
Widely used for processing printed wiring boards.

In this case, it is known that organic peroxides such as benzoyl peroxide and di-t-butyl peroxide can be used as a photopolymerization initiator. However, these organic peroxides generally only absorb light of 320 nm or less [Chem. Rev., 68 , 125-151 (1965)]. Attempts have been made to use a sensitizer in combination, but the transfer efficiency of light energy between molecules from the sensitizer to the organic peroxide is low, and the photodecomposition efficiency of the organic peroxide is low (J. Am. Chem. Soc., 87 , 3413-3417
(1965)].

In order to solve this problem, an ester type organic peroxide containing a benzophenone skeleton as a light absorbing group in the molecule has been developed (US Pat. No. 4,416,682).
No. 6, JP-A-59-197401).

[0005]

However, ester-type organic peroxides containing a benzophenone skeleton as a light absorbing group in the molecule have poor thermal stability.
There was a problem that the storage stability in a dark place was poor and the cured resin turned yellow.

[0006] On the other hand, peroxycarbonates are relatively thermally stable, but have a low efficiency in transferring light energy between molecules from the sensitizer to the organic peroxide. However, there is a problem that the photolysis efficiency is low.

[0007] The present invention has been made in view of the problems existing in the prior art as described above. The object is to provide a novel benzophenone skeleton-containing peroxide that has excellent storage stability, can suppress yellowing of the cured resin, and has high polymerization initiator efficiency, that is, high photopolymerization or photocuring efficiency, An object of the present invention is to provide a manufacturing method and a use thereof.

[0008]

Means for Solving the Problems In order to achieve the above object, a benzophenone skeleton-containing peroxide of the first invention is represented by the following general formula (1).

[0009]

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Wherein R ¹ is a tertiary alkyl group having 4 to 8 carbon atoms or an aromatic substituted tertiary alkyl group having 9 to 12 carbon atoms, and R ² is an alkylene group having 1 to 4 carbon atoms. The method for producing a benzophenone skeleton-containing peroxide according to the second invention comprises reacting a benzophenone skeleton-containing chloroformate represented by the following general formula (2) with a tertiary hydroperoxide.

[0011]

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(In the formula, R ² represents an alkylene group having 1 to 4 carbon atoms.) A method for producing a benzophenone skeleton-containing peroxide according to a third aspect of the present invention is a method for preparing a peroxyimidazole represented by the following general formula (3): It reacts with the hydroxyalkylbenzophenone derivative represented by the formula (4).

[0013]

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(In the formula, R ¹ represents a tertiary alkyl group having 4 to 8 carbon atoms or an aromatic substituted tertiary alkyl group having 9 to 12 carbon atoms, and R ³ represents a hydrogen atom or a methyl group.)

[0015]

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(In the formula, R ² represents an alkylene group having 1 to 4 carbon atoms.) A radical generator according to a fourth aspect of the present invention contains the benzophenone skeleton-containing peroxide of the first aspect as an active ingredient.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail. The novel benzophenone skeleton-containing peroxide is represented by the following general formula (1).

[0018]

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Wherein R ¹ is a tertiary alkyl group having 4 to 8 carbon atoms or an aromatic substituted tertiary alkyl group having 9 to 12 carbon atoms, and R ² is an alkylene group having 1 to 4 carbon atoms. In the benzophenone skeleton-containing peroxide represented by the general formula (1), the tertiary alkyl group having 4 to 8 carbon atoms represented by R ¹ is, for example, a t-butyl group, a t-amyl group, a t-amyl group.
Hexyl group, 1,1,3,3-tetramethylbutyl group and the like, and an aromatic substituted tertiary alkyl group having 9 to 12 carbon atoms is
For example, α-cumyl group, 2- (isopropylphenyl) propyl group and the like.

The alkylene group having 1 to 4 carbon atoms represented by R ² is, for example, a methylene group, a methylmethylene group, a dimethylmethylene group, an ethylene group, a trimethylene group, a tetramethylene group and the like.

Examples of the peroxide having a benzophenone skeleton represented by the general formula (1) include 4- (t-butylperoxycarbonyloxymethyl) benzophenone,
-(t-amylperoxycarbonyloxymethyl) benzophenone, 4- (t-hexylperoxycarbonyloxymethyl) benzophenone, 4- (1,1,3,3-tetramethylbutylperoxycarbonyloxymethyl) benzophenone, 4- (c Milperoxycarbonyloxymethyl) benzophenone, 4- (1- (isopropylphenyl) -1-methylethylperoxycarbonyloxymethyl) benzophenone, 4- (1- (t-butylperoxycarbonyloxy) ethyl) benzophenone, 4- (1 -(t-butylperoxycarbonyloxy) -1-methylethyl) benzophenone, 4- (2- (t-butylperoxycarbonyloxy) ethyl) benzophenone, 4- (3- (t-butylperoxycarbonyloxy) propyl) benzophenone , 3- (t-butylperoxycarbonyloxymethyl) benzophen Down, 2-(t-butylperoxy carbonyloxy-methyl)
Benzophenone, 4- (1- (methylphenyl) -1-methylethylperoxycarbonyloxymethyl) benzophenone, 4- (1- (ethylphenyl) -1-methylethylperoxycarbonyloxymethyl) benzophenone, 4-
(1- (t-butylperoxycarbonyloxy) butyl)
Benzophenone, 4- (1- (t-butylperoxycarbonyloxy) -1-methylpropyl) benzophenone and the like.

Next, a first method for producing a benzophenone skeleton-containing peroxide represented by the general formula (1) is a benzophenone skeleton-containing chloroformate represented by the following general formula (2) and a tertiary hydroperoxide. Is a production method.

[0023]

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(In the formula, R ² represents an alkylene group having 1 to 4 carbon atoms.) In the chloroformate having a benzophenone skeleton represented by the general formula (2), 1 to 4 carbon atoms represented by R ² Is the same as R ² in formula (1).

Examples of the chloroformate having a benzophenone skeleton represented by the general formula (2) include 4- (chloroformylmethyl) benzophenone, 4- (1-chloroformylethyl) benzophenone, and 4- (1-chloroformyl-). 1-methylethyl) benzophenone, 4- (2-chloroformylethyl) benzophenone, 4- (3-chloroformylpropyl) benzophenone, 3- (chloroformylmethyl) benzophenone, 2- (chloroformylmethyl) benzophenone, etc. .

The chloroformate having a benzophenone skeleton represented by the general formula (2) can be obtained, for example, by converting the corresponding hydroxyalkylbenzophenone using a chloroformate,
It can be obtained by subjecting it to chloroformylation by a conventional method. The chloroformylating agent is, for example, phosgene, diphosgene or triphosgene.

The tertiary hydroperoxide used in the first production method includes, for example, t-butyl hydroperoxide, t-amyl hydroperoxide, t-hexyl hydroperoxide, 1,1,3,3-tetramethylbutyl Hydroperoxide, α-cumyl hydroperoxide, diisopropylbenzene hydroperoxide and the like. The amount of the tertiary hydroperoxide used is 0.5 to 3.0 with respect to 1 mol of the chloroformate of the general formula (2).
Mole, preferably 0.8 to 1.2 mole.

In the first production method, in an organic solvent,
Reaction in the presence of a base facilitates the reaction,
It is preferable to improve the yield of the product. in this case,
As the organic solvent, for example, benzene, toluene, dioxane, tetrahydrofuran and the like are used. As the base, for example, sodium hydroxide, potassium hydroxide, pyridine and the like are used.
It is 0.5 to 5 mol, preferably 0.8 to 1.5 mol, per mol. The reaction temperature is -10 to 60 ° C, preferably 5 to 40.
° C.

Next, a second method for producing a benzophenone skeleton-containing peroxide represented by the general formula (1) is a method for preparing a peroxyimidazole represented by the following general formula (3) and a hydroxy compound represented by the general formula (4). It reacts with an alkylbenzophenone derivative.

[0030]

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(In the formula, R ¹ represents a tertiary alkyl group having 4 to 8 carbon atoms or an aromatic substituted tertiary alkyl group having 9 to 12 carbon atoms, and R ³ represents a hydrogen atom or a methyl group.)

[0032]

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(Wherein R ² represents an alkylene group having 1 to 4 carbon atoms.) In the peroxyimidazole represented by the general formula (3), R ¹
A tertiary alkyl group having 4 to 8 carbon atoms or an aromatic substituted tertiary alkyl group having 9 to 12 carbon atoms represented by the general formula (1)
Are the same to definitive R ^1, R ³ is a hydrogen atom or a methyl group.

The peroxyimidazoles of the general formula (3) include, for example, t-butylperoxycarbonylimidazole, t-amylperoxycarbonylimidazole, t-amylperoxycarbonylimidazole
Hexylperoxycarbonylimidazole, 1,1,3,3-
Tetramethylbutylperoxycarbonylimidazole, cumylperoxycarbonylimidazole, 1- (isopropylphenyl) -1-methylethylperoxycarbonylimidazole, t-butylperoxycarbonyl (2-methylimidazole) and the like.

The peroxyimidazole of the general formula (3) is carbonyldiimidazole or carbonylbis (2
-Methylimidazole) and hydroperoxide (Eur. Poly. J., 15 (1
1), 987-992 (1979)).

In the hydroxyalkylbenzophenone derivative of the formula (4), R ² is the same as R ² in the formula (1). Examples of the hydroxyalkylbenzophenone derivative of the general formula (4) include 4- (hydroxymethyl) benzophenone, 4- (1-hydroxyethyl) benzophenone, 4- (2-hydroxy-1-methylethyl) benzophenone, and 4- (2 -Hydroxyethyl) benzophenone, 4- (3-hydroxypropyl) benzophenone, 3- (hydroxymethyl) benzophenone, 2- (hydroxymethyl) benzophenone and the like.

The hydroxyalkylbenzophenone derivative represented by the general formula (4) can be obtained by (a) a method of alkyl-hydrolyzing a halogenated alkylbenzophenone derivative, and (b) after reacting the halogenated alkylbenzophenone derivative with sodium formate, sodium acetate, or the like. , And by a hydrolysis method.

In the second production method, the amount of peroxyimidazole used is 0.5 to 5 mol, preferably 0.8 mol, per 1 mol of hydroxyalkylbenzophenone.
~ 1.5 moles. The reaction solvent is, for example, dioxane,
Tetrahydrofuran or the like can be used. The reaction temperature is from -10 to 60C, preferably from 5 to 40C.

Next, a radical generator containing, as an active ingredient, a peroxide having a benzophenone skeleton represented by the general formula (1):
Used alone or as a mixture with other components, it is used as a photopolymerization initiator for photopolymerization or photocuring of radically polymerizable unsaturated compounds. At this time, in a mixture of one or more radically polymerizable unsaturated compounds and the photopolymerization initiator, a pigment, a filler, a coloring matter, a thermal polymerization inhibitor, a plasticizer, a solvent, which are generally used, Additives such as sensitizers and other known photopolymerization initiators can also be appropriately compounded. Such photosensitive compositions are used for paints, adhesives, printing inks, printing reliefs, printed wiring boards, photoresists, and the like.

When the benzophenone skeleton-containing peroxide of the general formula (1) is used as a photolytic radical generator, it can be used together with a radical polymerizable unsaturated compound, for example, as a photopolymerization initiator and a photocuring agent.

The photolysis is carried out by a known method, for example, 25
Irradiation with light having a wavelength of 0 to 500 nm, preferably 300 to 400 nm is performed. Light sources include sunlight, mercury lamps, mercury discharge tubes, xenon arc lamps, flash discharge tubes, tungsten lamps, halogen lamps, dye lasers, excimer lasers, and the like.

When the benzophenone skeleton-containing peroxide of the general formula (1) is used as a pyrolytic radical generator, it can be used together with a radically polymerizable unsaturated compound.
The pyrolysis temperature is 30-220 ° C, preferably 50-100 ° C.

Examples of the radical polymerizable unsaturated compound that can be used together with the radical generator include a polymerizable monomer, a polymerizable oligomer and a polymerizable unsaturated polymer.

The polymerizable monomer is a compound having one or more polymerizable double bonds, for example, an unsaturated carboxylic acid such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, crotonic acid, and itaconic acid; And derivatives of these unsaturated carboxylic acids, for example, methyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth)
Monoesters such as acrylate, phenyl (meth) acrylate, and benzyl (meth) acrylate; hydroxyesters such as 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate; ethylene glycol di (meth) acrylate; Polyhydric esters such as polyethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, (meth) acrylonitrile, (meth) acrylamide, And vinyl esters such as vinyl acetate, vinyl propionate, and vinyl succinate, vinyl ethers, styrene, alkylstyrene, and N-substituted (meth) acrylamide. , Halogenated styrene, divinylbenzene, vinyl naphthalene, N- vinylpyrrolidone,
Examples include vinyl compounds such as diallyl phthalate, diallyl maleate, triallyl isocyanate, and triallyl phosphate.

As the polymerizable oligomer, an isocyanate-modified oligomer, a polyester acrylic oligomer, a polyether acrylic oligomer and the like are used.
As the polymerizable unsaturated polymer, a curable resin having an allyl group, a (meth) acryl group, a malate group, a fumarate group, an unsaturated polyester, an unsaturated acrylic resin, and the like are used.

The radical generator varies depending on the type of the radically polymerizable unsaturated compound, but is preferably 0.001 to 5% by weight, preferably 0.1% by weight, based on the radically polymerizable unsaturated compound.
01 to 0.5% by weight.

According to the above embodiment, the following effects can be obtained. -The benzophenone skeleton-containing peroxide represented by the general formula (1) in the embodiment is a novel peroxide that has not been known before. -The benzophenone skeleton-containing peroxide of the embodiment has excellent storage stability based on a chemical structure different from the conventional peroxide. -The benzophenone skeleton-containing peroxide of the embodiment can suppress yellowing of the cured resin. -Since it has a light absorbing group (benzophenone) as a sensitizer in the molecule, it has high light energy transfer efficiency and high photolysis efficiency in the molecule. Therefore, the polymerization initiator efficiency, that is, the efficiency of photopolymerization or photocuring is excellent. -According to the first or second method for producing a benzophenone skeleton-containing peroxide, a desired novel benzophenone skeleton-containing peroxide can be easily produced at a high yield. According to the radical generator containing the novel benzophenone skeleton-containing peroxide of the embodiment as an active ingredient, a radical can be easily generated by light or heat, and a desired polymer or a polymer can be used together with a radical polymerizable unsaturated compound. A cured product can be easily obtained.

[0048]

Next, the present invention will be specifically described with reference to Reference Examples, Examples and Comparative Examples. Reference Example 1, Production of 4- (hydroxymethyl) benzophenone A stirrer, a thermometer, and a Dimroth condenser were provided.
82.9 g (0.301 mol) of 4- (bromomethyl) benzophenone was placed in a 1000 ml four-necked flask, and dissolved in 300 ml of dioxane. Sodium formate 61.5g (0.904mo
l) aqueous solution of tetra-n-butylammonium bromide 4.85
g (1.51 × 10 ⁻² mol) were added in order, and the mixture was refluxed for 3 hours.

After cooling to room temperature, 90.4 g of a 20% aqueous NaOH solution
(0.456 mol) was added dropwise little by little, and stirring was continued for 1 hour at room temperature. Thereafter, the organic layer was separated, and the aqueous layer was further extracted with diethyl ether (100 ml × 2). The combined organic layers were washed with saturated aqueous NaCl. After drying over anhydrous sodium sulfate and evaporating the solvent, the residue was recrystallized from a mixed solvent of toluene and n-hexane to obtain 54.7 g (0.258 mol) of 4- (hydroxymethyl) benzophenone as white crystals (yield: 85.5%). . (Reference Example 2, Production of t-butylperoxycarbonylimidazole) In a 200 ml four-necked flask equipped with a stirrer and a thermometer, 20.0 g of N, N'-carbonyldiimidazole (0.
123 mol) and 70 ml of anhydrous tetrahydrofuran. 12.2 g (0.129 mol) of t-butyl hydroperoxide was added dropwise little by little while cooling on ice and keeping the temperature at 5 ° C. or lower.
Thereafter, the ice bath was removed, and the reaction was continued at room temperature for 1 hour to obtain a solution of t-butylperoxycarbonylimidazole in tetrahydrofuran. (Example 1) 4- (chloroformylmethyl) benzophenone was placed in a 200 ml four-necked flask equipped with a stirrer and a thermometer.
27.5 g (0.100 mol) was added and dissolved in 90 ml of toluene. In addition, 70% t-butyl hydroperoxide aqueous solution 1
6.1 g (0.125 mol) was added, followed by ice cooling. 20% KOH aqueous solution 2
8.1 g (0.100 mol) was added dropwise while maintaining the temperature at 10 ° C or less.
Stirring was continued at 5 ° C for 90 minutes. The organic layer was washed with water, dried over anhydrous sodium sulfate, and the solvent was distilled off. Then, in methanol, recrystallized white crystals of 4- (t-butylperoxycarbonyloxymethyl) benzophenone 27.9 g
(0.0850 mol) was obtained (yield 85.0%). The obtained peroxide was subjected to nuclear magnetic resonance spectroscopy (NMR), infrared absorption spectroscopy (IR), mass spectroscopy (MS) and ultraviolet absorption spectroscopy (UV). The results are shown below. ¹ H-NMR (CDCl ₃ / TMS, δ (ppm)): 1.34 (9H, s), 5.31 (2H,
s), 7.4-7.9 (9H, m) IR (cm ^-1 ): 880 (OO), 1660 (C = O), 1780 (C = O) MS: 328 (M +) UV (dioxane, λmax (nm) ): .343 (ε = 151), 261 (ε
(Example 2) Instead of t-butyl hydroperoxide,
Using 15.3 g (0.125 mol) of 85% t-amyl hydroperoxide, the others were prepared according to Example 1, and white crystals of 4-
28.1 g (0.0821 mol) of (t-amyl peroxycarbonyloxymethyl) benzophenone was obtained (yield: 82.1%). The identification data of the obtained peroxide is shown below. ¹ H-NMR (CDCl ₃ / TMS, δ (ppm)): 0.98 (3H, t), 1.30 (6H,
s), 1.56 (2H, q), 5.32 (2H, s), 7.4-7.9 (9H, m) IR (cm ^-1 ): 880 (OO), 1660 (C = O), 1780 (C = O) MS: 342 (M +) UV (dioxane, λmax (nm)): .343 (ε = 149), 261 (ε
Example 15 Instead of t-butyl hydroperoxide,
16.4g (0.125mol) of 90% t-hexyl hydroperoxide
Was prepared according to Example 1 except that
28.8 g (0.0807 mol) of (t-hexylperoxycarbonyloxymethyl) benzophenone was obtained (80.7% yield).
The identification data of the obtained peroxide is shown below. ¹ H-NMR (CDCl ₃ / TMS, δ (ppm)): 0.93 (3H, t), 1.29 (6H,
s), 1.41 (2H, m), 1.59 (2H, t), 5.32 (2H, s), 7.4-7.9
(9H, m) IR (cm ^-1 ): 880 (OO), 1660 (C = O), 1780 (C = O) MS: 356 (M +) UV (dioxane, λmax (nm)): .343 (ε = 147), 261 (ε
(Example 4) Instead of t-butyl hydroperoxide,
90% 1,1,3,3-tetramethylbutyl hydroperoxide 2
Except that 0.3 g (0.125 mol) was used, it was produced according to Example 1, and white crystals of 4- (1,1,3,3-tetramethylbutylperoxycarbonyloxymethyl) benzophenone 29.3 g
(0.0763 mol) was obtained (yield 76.3%). The identification data of the obtained peroxide is shown below. ¹ H-NMR (CDCl ₃ / TMS, δ (ppm)): 1.03 (9H, s), 1.38 (6H,
s), 1.65 (2H, s), 5.32 (2H, s), 7.4-7.9 (9
H, m) IR (cm ^-1 ): 880 (OO), 1660 (C = O), 1780 (C = O) MS: 384 (M +) UV (dioxane, λmax (nm)): .343 (ε = 151), 261 (ε
= 15000) (Example 5) Instead of t-butyl hydroperoxide,
Except that 23.8 g (0.125 mol) of 80% cumene hydroperoxide was used, the production was carried out according to Example 1, to obtain 30.2 g (0.0774 mol) of 4- (cumylperoxycarbonyloxymethyl) benzophenone as white crystals ( Yield 77.4%). The identification data of the obtained peroxide is shown below. ¹ H-NMR (CDCl ₃ / TMS, δ (ppm)): 1.65 (6H, s), 5.33 (2H,
s), 7.3-8.0 (14H, m) IR (cm ^-1 ): 880 (OO), 1660 (C = O), 1780 (C = O) MS: 390 (M +) UV (dioxane, λmax (nm) ): .343 (ε = 165), 261 (ε
(Example 17) Except that 30.3 g (0.100 mol) of 4- (1-chloroformyl-1-methylethyl) benzophenone was used instead of 4- (chloroformylmethyl) benzophenone,
It was manufactured according to Example 1 to obtain 25.8 g (0.0723 mol) of 4- (1- (t-butylperoxycarbonyloxy) -1-methylethyl) benzophenone as white crystals (yield: 72.3%). The identification data of the obtained peroxide is shown below. ¹ H-NMR (CDCl ₃ / TMS, δ (ppm)): 1.33 (9H, s), 1.65 (6H,
s), 7.4-8.1 (9H, m) IR (cm ^-1 ): 880 (OO), 1660 (C = O), 1780 (C = O) MS: 356 (M +) UV (dioxane, λmax (nm) ): .345 (ε = 181), 266 (ε
(Example 7) In place of 4- (chloroformylmethyl) benzophenone, 27.5 g (0.100 mol) of 3- (1-chloroformyl-1-methylethyl) benzophenone was used.
It was produced according to Example 1 to obtain 22.9 g (0.0698 mol) of 3- (1- (t-butylperoxycarbonyloxy) -1-methylethyl) benzophenone as white crystals (yield 69.8%). The identification data of the obtained peroxide is shown below. ¹ H-NMR (CDCl ₃ / TMS, δ (ppm)): 1.33 (9H, s), 5.30 (2H,
s), 7.1-8.1 (9H, m) IR (cm ^-1 ): 880 (OO), 1660 (C = O), 1780 (C = O) MS: 328 (M +) UV (dioxane, λmax (nm) ): .343 (ε = 147), 263 (ε
(Example 8) 23.8 g of 4- (hydroxymethyl) benzophenone in a tetrahydrofuran solution of t-butylperoxycarbonylimidazole obtained in Reference Example 2 at room temperature under stirring.
(0.112 mol) in tetrahydrofuran (40 ml) was added dropwise while keeping the temperature at 20 ° C. or lower. After the temperature was raised to 40 ° C., stirring was continued for 6 hours. After cooling, tetrahydrofuran is distilled off,
Dissolved in diethyl ether and washed with saturated aqueous NH ₄ Cl, then saturated aqueous NaCl. After drying over anhydrous sodium sulfate and evaporating the solvent, 4- (t-
Butylperoxycarbonyloxymethyl) benzophenone was obtained in an amount of 21.2 g (0.0641 mol) (yield: 57.3%). (Examples 9 to 13, photopolymerization) Into a photopolymerization tube made of quartz, 0.01 mol / l of each of the radical generators obtained in Examples 1 to 5 was added to methyl methacrylate containing no polymerization inhibitor, followed by freeze-thawing. Merry-go-round type light irradiator (manufactured by Daika Kogyo Co., Ltd., trade name: MGR-P)
With a 400W high-pressure mercury lamp (using a UVT 36A filter)
After irradiating with ultraviolet rays of 5 nm from a distance of 8 cm for 30 minutes, the polymerization conversion rate and the polymerization rate (Rp) were determined by the gravimetric method by the methanol precipitation method.
Was measured. Table 1 shows the obtained results. (Comparative Example 1) Instead of the radical generators of Examples 9 to 13,
Except that 2- (t-butylperoxycarbonyloxy) propane and benzophenone were used in an amount of 0.01 mol / l each, methyl methacrylate was polymerized according to the method described in Examples 9 to 13, and the polymerization conversion rate and polymerization rate were changed. It was measured. Table 1 shows the results.

[0050]

[Table 1]

As shown in Table 1, in Examples 9 to 13, it was found that the polymerization conversion rate and the initial polymerization rate were excellent, and that they had effective photopolymerization performance. On the other hand, in Comparative Example 1 using the conventional peroxide, the polymerization conversion rate and the initial polymerization rate were low, and the photopolymerization performance was poor. (Examples 14 to 18, photocuring) Ester acrylate resin (composition is "Aronix M-8060" (Toa Gosei Co., Ltd.)) on a glass plate to which 2 parts by weight of each of the radical generators obtained in Examples 1 to 5 was added. Product name) / "Aronix
M-5700 ”(product name of Toa Gosei Co., Ltd. = 4/6)
Conveyor type UV curing device (light collecting type)
The coating was repeatedly passed under a high-pressure mercury lamp until the surface of the coating film hardened to a pencil hardness of 4H. Table 2 shows the number of passages until curing. The energy of light irradiated in one pass was about 80 mJ / cm ² . Table 2 shows the results. Further, there was no visual yellowing of this resin. (Comparative Examples 2-3) Instead of the radical generators of Examples 14-18, 2- (t-butylperoxycarbonyloxy) propane and benzophenone were used in an amount of 0.01 mol / l,
(t-butylperoxycarbonyl) The ester acrylate resin was cured according to the method described in Examples 14 to 18 except that benzophenone was used. Table 2 shows the results.

[0052]

[Table 2]

As shown in Table 2, in Examples 14 to 18, it was found that a predetermined hardness was obtained with a small number of passages, the resin did not turn yellow, and had an effective photocuring performance. On the other hand, in Comparative Examples 2 and 3 using the conventional peroxide, the number of passages was large or the resin was yellowed. (Examples 19 to 23, storage stability) An ester acrylate resin (composition: "Aronix M-8060" (Toa Gosei) in which 2 parts by weight of each of the radical generators obtained in Examples 1 to 5 was added to a glass bottle Company name) / "Aronix
M-5700 ”(product name of Toa Gosei Co., Ltd.) = 4/6), and the storage stability in a dark place at 60 ° C. in an incubator was examined. The results were visually expressed as the number of days when gelation occurred. Table 3 shows the obtained storage stability in a dark place. (Comparative Examples 4 and 5) Storage stability according to the methods described in Examples 19 to 23, except that 2 parts by weight of each of the conventional photopolymerization initiators shown in Table 3 was used as the photopolymerization initiator. Was examined. Table 3 shows the results. Examples 9-1
The chemical structural formulas of the peroxides or photopolymerization initiators used in No. 3 and Comparative Examples 1, 3, and 5 are shown below.

[0054]

[Table 3]

The peroxide of Example 9 has the chemical structural formula (1)
It has the structure shown in 3).

[0056]

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The peroxide of Example 10 has the structure shown in chemical structural formula (14).

[0058]

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The peroxide of Example 11 has the structure shown in chemical structural formula (15).

[0060]

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The peroxide of Example 12 has the structure shown in chemical structural formula (16).

[0062]

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The peroxide of Example 13 has the structure shown in chemical structural formula (17).

[0064]

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The peroxide of Comparative Example 1 has the chemical structural formula (1)
It has the structure shown in 8).

[0066]

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Benzophenone has the structure shown in chemical structural formula (19).

[0068]

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The peroxide of Comparative Example 3 has the chemical structural formula (2)
0).

[0070]

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The photopolymerization initiator of Comparative Example 5 has the chemical structural formula (2)
It has the structure shown in 1).

[0072]

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As shown in Table 3, in Examples 19 to 23, storage stability in a dark place for 30 days or more was obtained, and it was revealed that the storage stability in a dark place was excellent. On the other hand, in Comparative Examples 4 and 5 using the conventional peroxide,
The dark storage stability was 5 or 6 days.

The technical ideas grasped from the above embodiment will be described below. The method for producing a benzophenone skeleton-containing peroxide according to claim 2, wherein the benzophenone skeleton-containing chloroformate represented by the general formula (2) is reacted with a tertiary hydroperoxide in an organic solvent in the presence of a base.

With such a constitution, the reaction can be carried out smoothly and the yield of the peroxide having a benzophenone skeleton can be improved.

[0076]

As described above in detail, according to the present invention, the following excellent effects can be obtained. The benzophenone skeleton-containing peroxide of the first invention is a novel compound,
It is excellent in storage stability, can suppress yellowing of the cured resin, and is excellent in polymerization initiator efficiency, that is, photopolymerization or photocuring efficiency.

According to the method for producing a benzophenone skeleton-containing peroxide according to the second and third aspects of the present invention, the desired novel benzophenone skeleton-containing peroxide can be easily produced in high yield.

According to the radical generator of the fourth invention, radicals can be easily generated by light or heat.
Various polymers and cured products can be obtained by using together with the radical polymerizable unsaturated compound.

Claims (4)

[Claims] 1. A peroxide having a benzophenone skeleton represented by the following general formula (1). Embedded image (In the formula, R ¹ represents a tertiary alkyl group having 4 to 8 carbon atoms or an aromatic substituted tertiary alkyl group having 9 to 12 carbon atoms, and R ² represents an alkylene group having 1 to 4 carbon atoms.) 2. The process for producing a benzophenone skeleton-containing peroxide according to claim 1, wherein the benzophenone skeleton-containing chloroformate represented by the following general formula (2) is reacted with a tertiary hydroperoxide. Embedded image (In the formula, R ² represents an alkylene group having 1 to 4 carbon atoms.) 3. The method for producing a benzophenone skeleton-containing peroxide according to claim 1, wherein a peroxyimidazole represented by the following general formula (3) is reacted with a hydroxyalkylbenzophenone derivative represented by the following general formula (4). Embedded image (In the formula, R ¹ represents a tertiary alkyl group having 4 to 8 carbon atoms or an aromatic substituted tertiary alkyl group having 9 to 12 carbon atoms, and R ³ represents a hydrogen atom or a methyl group.) ] (In the formula, R ² represents an alkylene group having 1 to 4 carbon atoms.) 4. A radical generator comprising the benzophenone skeleton-containing peroxide according to claim 1 as an active ingredient.