JPH06321895A - Peroxyketal and its use - Google Patents

Abstract

PURPOSE:To obtain the subject novel compound consisting of a benzophenone derivative having a peroxyketal group, generating radicals with light and heat in a high efficiency, and useful for polymerization initiators, etc., as a light or heat-decomposition type radical generator. CONSTITUTION:An acid halide of formula I (X is halogen; (m), (n) are respectively such an integer of 0-2 as (m+n) is an integer of 1-4) (e.g. 4,4'-benzophenone dicarboxylic acid dichloride) is reacted with a hydroxy group-substituted ketone of formula II (R2 is 1-4C alkylene; R3 is 1-2C alkyl)(e.g. hydroxyacetone) in the presence of a base (e.g. pyridine) in a solvent such as benzene, and subsequently reacting the produced ketoester derivative of formula III with a hydroperoxide of the formula: R1-OOH (R1 is 4-10C tertiary alkyl) (e.g. t-butyl hydroperoxide) in the presence of an acid catalyst (e.g. sulfuric acid) to provide the objective peroxyketal of formula IV.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novel peroxyketal containing a specific benzophenone group in the molecule and its use. In the present invention, the photodegradable radical generator is a general term for a photopolymerization initiator, a photocuring agent, and a photocrosslinking agent, and the thermal decomposition type radical generator is a thermal polymerization initiator,
It is a general term for heat curing agents and heat crosslinking agents.

[0002]

2. Description of the Related Art In general, photopolymerization, photocurable monomer, photopolymerization, photopolymerization and photocuring of a photocurable resin composition are carried out by a method which is higher than a thermal polymerization method, a thermosetting method or an oxidative curing method. Can be polymerized and cured at low temperature and quickly,
It has many advantages such as productivity improvement, energy saving, pollution-free, and selective curing, so printing ink,
It is widely used for coatings, adhesives, resin letterpress, and printed wiring board processing.

In this photopolymerization and photocuring method, various initiators have been developed so far for use therein. For example, photopolymerization initiators that generate radicals under the action of ultraviolet rays, such as benzoin, benzoin ethers, benzyl, aryldiazonium salts, benzophenone derivatives, acetophenone derivatives, xanthates, thioxanthones, and halogenated hydrocarbons are known. [Journal of Oil and Color Chemistry Association (Journal of Oil
and Color Chemist's Assoc
iation), 59, 166-171 (19
1976)].

It is known that organic peroxides such as benzoyl peroxide and di-t-butyl peroxide can also be used as the photopolymerization initiator. However, these organic peroxides generally absorb only light of 320 nm or shorter [Chemical Review (Chemical Re
view), Volume 68, Pages 125-151 (1965)
)], It was attempted to use a sensitizer in combination with these, but the intermolecular light energy transfer efficiency from the sensitizer to the organic peroxide was low, and the photodecomposition efficiency of the organic peroxide was also low. Low. [Journal of the American Chemical Society (Journal of the
American ChemicalSociet
y), 87, 3413-3417 (1965).
Year)〕.

As a solution to this problem, ester type organic peroxides containing a benzophenone group as a light absorbing group in the molecule have been developed [US Pat. No. 4,416].
826] [JP-A-59-197401]
However, these compounds had drawbacks such as poor storage stability in the dark and yellowing of the obtained cured product. On the other hand, peroxyketals are relatively stable to heat, but when used in combination with a sensitizer, the photodegradation efficiency is low, and in addition, peroxyketals having a light-absorbing group in the molecule are known to date. Not not.

The peroxyketals are generally 1
It is known that radicals are effectively generated at a high temperature of 00 ° C. or higher, and examples thereof include 1,1-bis (t-butylperoxy) cyclohexane and 1,1-bis (t-
Butylperoxy) -3,3,5-trimethylcyclohexane and 2,2-bis (t-butylperoxy) butane are industrially used as a thermal polymerization initiator, a curing agent, and a crosslinking agent.

[0007]

The above-mentioned conventional photopolymerization initiators are useful, but have some drawbacks to be improved. For example, (1) benzoin and benzoin ethers have poor storage stability in the dark. (2) The benzophenone derivative is used in combination with an amine or the like, but the obtained polymer or cured product turns yellow. (3) Thioxanthones have low solubility in monomers and resin compositions. (4) The ester type organic peroxide containing a benzophenone group as a light absorbing group has poor thermal stability and the obtained cured product also turns yellow. (5) The combined use system of peroxyketals and a sensitizer has low photolysis efficiency. And so on.

[0008]

The present inventors have improved the drawbacks of these conventional photopolymerization initiators, have good thermal stability, have little yellowing of the resulting polymer or cured product, and As a result of intensive research aimed at obtaining a photolytic radical generator having high efficiency of polymerization and photocuring and having high industrial value, as a result of the novel peroxyketal containing a benzophenone group as a light absorbing group in the molecule, Knowing that the purpose can be achieved, the present invention has been completed. That is, the first aspect of the present invention is the general formula

[Chemical 4] (In the formula, R ₁ is a tertiary alkyl group having 4 to 10 carbon atoms or a tertiary aralkyl group having 9 to 12 carbon atoms, and R ₂ is 1 to 3 carbon atoms.
4 is an alkylene group, R ₃ is an alkyl group having 1 to 2 carbon atoms, and m and n are each an integer of 0 to 2 such that m + n is an integer of 1 to 4. ) Is a novel peroxyketal, the second of the present invention is a photodegradable radical generator containing the novel peroxyketal as an active ingredient, and the third of the present invention is the same as the novel peroxyketal. It is a thermal decomposition type radical generator containing peroxyketal as an active ingredient.

Specific examples of the peroxyketal of the present invention include: (1) 4- {2,2-bis (t-butylperoxy) propyloxycarbonyl} benzophenone (2) 4- {2,2-bis (T-Amylperoxy) propyloxycarbonyl} benzophenone (3) 4- {2,2-bis (t-hexylperoxy)
Propyloxycarbonyl} benzophenone (4) 4- {2,2-bis (t-octylperoxy)
Propyloxycarbonyl} benzophenone (5) 4- {2,2-bis (t-decylperoxy) propyloxycarbonyl} benzophenone (6) 4- {2,2-bis (cumylperoxy) propyloxycarbonyl} benzophenone (7) ) 4- [2,2-bis {1- (isopropylphenyl) -1-methylethylperoxy} propyloxycarbonyl] benzophenone (8) 4- {2,2-bis (t-butylperoxy) butyloxycarbonyl} benzophenone (9) 4- {2,2-bis (t-butylperoxy)-
1-Methylpropyloxycarbonyl} benzophenone (10) 4- {2,2-bis (t-butylperoxy)
-1,1-Dimethylpropyloxycarbonyl} benzophenone (11) 4- {3,3-bis (t-butylperoxy)
Butyloxycarbonyl} benzophenone (12) 4- {3,3-bis (t-butylperoxy)
2-Methylbutyloxycarbonyl} benzophenone (13) 4- {3,3-bis (t-butylperoxy)
-2,2-Dimethylbutyloxycarbonyl} benzophenone (14) 4- {4,4-bis (t-butylperoxy)
Pentyloxycarbonyl} benzophenone (15) 3- {2,2-bis (t-butylperoxy)
Propyloxycarbonyl} benzophenone (16) 2- {2,2-bis (t-butylperoxy)
Propyloxycarbonyl} benzophenone (17) 4,4'-bis {2,2-bis (t-butylperoxy) propyloxycarbonyl} benzophenone (18) 3,4-bis {2,2-bis (t-butylperoxy) ) Propyloxycarbonyl} benzophenone (19) 3,4,4'-tris {2,2-bis (t-butylperoxy) propyloxycarbonyl} benzophenone (20) 3,3 ', 4,4'-tetrakis {2 , 2-bis (t-butylperoxy) propyloxycarbonyl} benzophenone.

The peroxyketal of the present invention can be produced by the following method. That is, the general formula

[Chemical 5] (Wherein, X represents a halogen atom, and m and n each represent an integer of 0 to 2 such that m + n is an integer of 1 to 4).

[Chemical 6] (In the formula, R ₂ represents an alkylene group having 1 to 4 carbon atoms and R ₃ represents an alkyl group having 1 to 2 carbon atoms), which is obtained by reacting with a hydroxyl group-substituted ketone in the presence of a base. General formula

[Chemical 7] (In the formula, R ₂ , R ₃ , m, and n are respectively represented by the general formula 5,
The same thing as the chemical formula 6 is shown. ) In the presence of an acid catalyst, a compound represented by the general formula

[Chemical 8] (In the formula, R1 represents a tertiary alkyl group having 4 to 10 carbon atoms or a tertiary aralkyl group having 9 to 12 carbon atoms). The peroxyketal obtained is purified by column chromatography or recrystallization. The novel peroxyketal produced as above is obtained as a white solid at room temperature, and each of the obtained peroxyketals has an infrared absorption spectrum, a nuclear magnetic resonance spectrum, an ultraviolet absorption spectrum, a mass spectrum and elemental analysis. Allows its structure to be identified.

The peroxyketal of the present invention is used singly or in a mixture with other components as a photopolymerization initiator or a photocuring agent for photopolymerization or photocuring of radically polymerizable unsaturated compounds. At this time, pigments, fillers, dyes, and thermal polymerization inhibitors that are usually used in a mixture of one or more radically polymerizable unsaturated compounds and the photopolymerization initiator or photocuring agent of the present invention. , A plasticizer, a solvent, a sensitizer, or other known additives such as a photopolymerization initiator can be appropriately mixed, and such a photosensitive composition can be used as a paint, an adhesive, a printing ink, a printing letterpress. Used for printed wiring boards, photoresists, etc. Further, the peroxyketal of the present invention, by combining with a dye sensitizer such as camphorquinone and thiopyrylium salt, polymerization by visible light,
Curing is also possible.

Radical polymerizable unsaturated compounds which can be photopolymerized and photocured by blending the photopolymerization initiator and the photocuring agent of the present invention include polymerizable monomers, polymerizable oligomers, and polymerizable unsaturated compounds. Examples include polymers. The polymerizable monomer is a compound having one or more polymerizable double bonds,
For example, unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, crotonic acid, itaconic acid; derivatives of these unsaturated carboxylic acids; for example, methyl (meth) acrylate, butyl (meth) acrylate, 2 -Ethylhexyl (meth) acrylate, phenyl (meth) acrylate, benzyl (meth) acrylate and other monoesters, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate and other hydroxy esters, ethylene glycol di (Meth) acrylate, polyethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate Polyvalent esters, (meth)
(Meth) acrylic acid compounds such as acrylonitrile, (meth) acrylamide, N-substituted (meth) acrylamide, vinyl acetates such as vinyl acetate, vinyl propionate, vinyl succinate, vinyl ethers, styrene, alkylstyrene, Examples thereof include vinyl compounds such as halogenated styrene, divinylbenzene, vinylnaphthalene, N-vinylpyrrolidone, diallylphthalate, diallyl maleate, triallyl isocyanate and triallyl phosphate. Examples of the polymerizable oligomer and the polymerizable unsaturated polymer include a curable resin having a maleate group, a fumarate group, an allyl group, and a (meth) acrylate group, an unsaturated polyester resin, an unsaturated acrylic resin, and an isocyanate-modified acrylic resin. Examples thereof include oligomers, polyester acrylic oligomers and polyether acrylic oligomers.

Examples of the polymer crosslinked by the photocrosslinking agent of the present invention include polyethylene, ethylene propylene copolymer, ethylene propylene diene copolymer, ethylene vinyl acetate copolymer, tetrafluoroethylene vinylidene fluoride hexafluoropropylene ternary copolymer, Chlorosulfonated polyethylene, chlorinated polyethylene, polybutene-1, polyisobutene, ethylene vinyl acetate copolymer, polybutadiene, polyisoprene, polychloroprene, butadiene styrene copolymer, natural rubber, polyacrylate rubber, butadiene acrylonitrile copolymer, acrylonitrile butadiene styrene ternary copolymer, Examples include silicone rubber, polyurethane and polysulfide.

The amount of the photolytic radical generator of the present invention to be used is basically 0.01 to 10% by weight, preferably 0.1 to 4% by weight based on the radically polymerizable unsaturated compound or the polymer to be crosslinked. %, But is affected by the type of additives added at the same time. For example, when a pigment having poor light transmittance is added as an additive, it may be necessary to increase the amount of the photodegradable radical generator used. However, if the amount used is too large, an unreacted photodegradable radical generator may remain in the product, possibly deteriorating the physical properties of the product. On the other hand, if the amount is too small, the reaction will not be completed and unreacted unsaturated compounds will remain.

The reaction of the radically polymerizable unsaturated compound or the polymer to be crosslinked, which contains the photodegradable radical generator of the present invention, is carried out by irradiation of light in the wavelength range of 250 to 500 nm, preferably 300 to 400 nm, by a known method. To do. Light sources that can be used include sunlight, mercury lamps,
Examples include mercury discharge tubes, xenon arc lamps, flash discharge tubes, tungsten lamps, halogen lamps, dye lasers and excimer lasers.

The above description relates to the photodegradable radical generator containing the peroxyketal of the present invention as an active ingredient. In addition to this, the present inventors further pursue the use of the peroxyketal of the present invention. As a result,
It has been found that the heat-decomposable radical generator containing the peroxyketal of the present invention as an active ingredient exhibits excellent performance in the thermal polymerization, thermosetting and thermal crosslinking of the monomer, the resin composition and the polymer.

The vinyl monomer thermally polymerized by the thermal polymerization initiator of the present invention includes, for example, styrene, α-methylstyrene, acrylonitrile, acrylic acid esters, methacrylic acid esters, maleic acid esters,
Examples include fumaric acid esters, maleimides, butadiene, vinyl acetate and the like. Further, to these monomers, various other chain transfer agents, a rubber component or a foaming agent such as pentane may be added, and the thermal polymerization initiator includes other thermal polymerization initiators having different thermal decomposition temperatures. You can use it together.
The addition amount of the thermal polymerization initiator of the present invention varies depending on the type of monomer used for thermal polymerization or a combination thereof, but is generally 0.001 in terms of a pure product based on 100 parts by weight of the charged amount of the monomer. To 5 parts by weight, preferably 0.01 to
0.5 parts by weight. If the amount is less than 0.001 part by weight, the polymerization rate tends to be slow, and if it exceeds 5 parts by weight, it is not economical and not preferable.

The thermal polymerization method used in the present invention is
In the ordinary bulk polymerization, solution polymerization or suspension polymerization method, the polymerization temperature is generally 60 to 150 ° C, preferably 80 to
It is 130 ° C. The polymerization temperature is a constant temperature or a relatively low temperature at the initial stage of the polymerization, and a method of raising the temperature stepwise as the polymerization proceeds is used. As the polymer obtained in the present invention, GP type polystyrene, impact-resistant polystyrene, expanded polystyrene, polymethylmethacrylate, styrene / acrylonitrile copolymer, styrene / acrylonitrile / phenylmaleimide copolymer, which are used for general molding materials, Examples thereof include various acrylic acid or methacrylic acid ester copolymers such as butyl methacrylate / 2-ethylhexyl methacrylate copolymer.

The unsaturated polyester resin which is thermally cured by the thermosetting agent of the present invention includes (a) maleic anhydride or fumaric acid as an unsaturated dibasic acid, phthalic anhydride or isophthalic acid as a saturated dibasic acid. , Adipic acid, tetrachlorophthalic anhydride, ethylene glycol as a polyhydric alcohol, propylene glycol, 1,3-butylene glycol, diethylene glycol, dipropylene glycol, neopentyl glycol, etc. at a specific ratio under a nitrogen stream of 170- Alkyd resin obtained by condensation at 200 ° C., and (b) styrene, o-chlorostyrene,
It is a mixed composition with vinyl monomers such as vinyltoluene, methyl methacrylate, diallyl phthalate and triallyl cyanurate. Further, glass fibers as an additive to the unsaturated polyester resin include chopped strand mat, glass woven fabric, and continuous mat, and fillers include calcium carbonate, aluminum hydroxide and the like, which are used to manufacture FRP molded products. Is generally used for.

The amount of the thermosetting agent of the present invention used is 0.1 to 3 parts by weight, preferably 0.5 to 2 parts by weight, based on 100 parts by weight of the unsaturated polyester resin. Moreover, the content of the glass fiber and the filler is preferably in the range of 10 to 80 parts by weight which is generally used. The heat curing temperature, such as the use of the heat curing agent of the present invention, is 60 ° C. or higher, preferably 80
~ 170 ° C.

As the polymer crosslinked by the thermal crosslinking agent of the present invention, the polymer crosslinked by the above photocrosslinking agent can be used as it is. The thermal crosslinking agent of the present invention is generally 0.1 to 10% by weight based on the polymer to be crosslinked.
It is preferably added in the range of 1 to 3% by weight. Further, to the polymer to be crosslinked, it is possible to add various kinds of additives generally used in the thermal crosslinking reaction, for example, a crosslinking aid, an antioxidant, a pigment, an ultraviolet stabilizer, a filler, a plasticizer and the like. . In the thermal crosslinking reaction of the present invention, the temperature at which the polymer to be crosslinked and the organic peroxide are mixed is generally 25 to
130 ° C. is used and the temperature of the subsequent crosslinking is generally 110
-220 degreeC, Preferably 150-190 degreeC is used.

[0022]

The peroxyketal of the present invention has the following characteristics as compared with the conventional photopolymerization initiator, photocuring agent and photocrosslinking agent. (1) Since it has a light absorbing group and a radical generating source in the same molecule, it is possible to efficiently generate radicals by irradiation with light, and thus the photopolymerization and photocuring speeds are high. (2) Since it is a dialkyl-type peroxide, it has good thermal stability, and therefore a photopolymerizable composition containing it can be stored for a long period of time without polymerization or gelation. (3) When this is used as a photopolymerization initiator, a photocuring agent, or a photocrosslinking agent, a product can be obtained easily and in good yield, and the obtained product does not yellow. (4) Since it is a peroxide, if curing by photocuring is insufficient, aftercuring by heat curing is possible. In addition, the peroxyketal of the present invention can also effectively generate radicals as a thermal polymerization initiator, a curing agent, and a crosslinking agent. As described above, the peroxyketal of the present invention is a novel compound having excellent characteristics as a photo- and thermal-decomposition type radical generator, and has an extremely high industrial value.

[0023]

[Examples and Comparative Examples] Next, according to Examples and Comparative Examples,
The present invention will be specifically described, but the present invention is not limited thereto. In addition, the part in an example shows a weight part.

Example 1 (Production of peroxyketal) In a 300 ml four-necked flask equipped with a stirrer and a thermometer, 14.8 g (0.2 mol) of hydroxyacetone and 16.6 g (0.21 mol) of pyridine were prepared. Then, 100 ml of benzene was added, and 100 ml of a benzene solution of 48.9 g (0.2 mol) of 4-benzoylbenzoyl chloride was added dropwise with stirring at room temperature. Then, the temperature was raised, and stirring was continued for 7 hours under reflux. After removing the precipitated crystals, the crystals were washed with a dilute hydrochloric acid aqueous solution, a 5% sodium hydroxide aqueous solution, and then with water, and dehydrated with magnesium sulfate. After the solvent was distilled off, the residue was crystallized in ethanol to give 39.5 g of 2-oxo-propyl-4-benzoylbenzoate as a white solid.
Got 28.2 g of the obtained white solid, 19.8 g of t-butyl hydroperoxide and 50 ml of benzene were added to 2 parts.
The mixture was placed in a 00 ml four-necked flask, 15.1 g of 65% sulfuric acid was added dropwise over 15 minutes under ice cooling, and stirring was continued for another 2 hours. After removing the aqueous layer, it was washed with a 5% aqueous sodium hydroxide solution and then with water, dehydrated, distilled off the solvent, and crystallized in ether to obtain 28.9 g of a white solid. The results of infrared absorption spectrum, nuclear magnetic resonance spectrum, ultraviolet absorption spectrum, mass spectrum, elemental analysis, and melting point measurement of this compound are as follows. 2, 2
-Bis (t-butylperoxy) propyloxycarbonyl} benzophenone was confirmed.

[Chemical 9] Infrared absorption spectrum 880 cm ^-1 (O-O bond) 1670 cm ^-1 (C = O bond (ketone)) 1730 cm ^-1 (C = O bond (ester)) Nuclear magnetic resonance spectrum (δ) (a) 1.25 ppm ( 18H) (b) 1.57ppm (3H) (c) 4.58ppm (2H) (d) 7.4-8.2ppm (9H) UV absorption spectrum (in dioxane) 256nm (ε26100) 345nm (ε169) mass Spectrum (m / e) 444 (molecular ion peak) Elemental analysis C; 67.59% (calculated value 67.55%) H; 7.19% (calculated value 7.26%) Melting point 92-93 ° C

Examples 2 and 3 (Production of Peroxyketal) In Example 1, instead of hydroxyacetone, 4-hydroxy-2-butanone (referred to as Example 2) and 5-hydroxy-2-pentanone (Example) were prepared. A white solid was obtained in each case by a method similar to the production method described in Example 1 except that Example 3) was used. Each of the obtained compounds was analyzed in the same manner as in Example 1, and as a result, it was confirmed that these compounds were the target peroxyketals. The compounds obtained and the results of each analysis are summarized in Table 1.

Examples 4, 5 (Production of Peroxyketal) In Example 1, instead of 4-benzoylbenzoic acid chloride, 4,4'-benzophenone dicarboxylic acid dichloride (referred to as Example 4), 3, 3 respectively. ', 4, 4
A white solid was obtained in each case by a method similar to the production method described in Example 1 except that ′ -benzophenone tetracarboxylic acid tetrachloride (referred to as Example 5) was used. About the obtained compounds, respectively, Example 1
As a result of conducting each analysis in the same manner as in, it was confirmed that these compounds were the target peroxyketals. The compounds obtained and the results of each analysis are summarized in Table 1.

[0027]

[Table 1]

Examples 6 to 9 (Production of peroxyketal) In Example 1, instead of t-butyl hydroperoxide, t-amyl hydroperoxide and t-amyl hydroperoxide, respectively.
Except that hexyl hydroperoxide, t-octyl hydroperoxide, cumene hydroperoxide (in this order, Examples 6 to 9) are used, the procedure is the same as the production method described in Example 1, and in each case Also gave a white solid. Each of the obtained compounds was analyzed in the same manner as in Example 1, and as a result, it was confirmed that these compounds were the target peroxyketals. The compounds obtained and the results of each analysis are summarized in Table 2.

[0029]

[Table 2]

Examples 10 to 12 (Photopolymerization) Into a quartz photopolymerization tube, 0.01 mol / l of each of the photopolymerization initiators of the present invention shown in Table 3 was added to methyl methacrylate containing no polymerization inhibitor. And nitrogen substitution by freeze-thaw method, and then using a merry-go-round type light irradiation device (manufactured by Daishin Kogyo Co., Ltd., trade name MGR-P type) in a thermostat of 20 ° C., using a 400 W high-pressure mercury lamp (UVD36A filter), 365 nm Was irradiated for 30 minutes from a distance of 8 cm. After that, the polymerization conversion rate and the polymerization rate (Rp) were measured by the weight method based on the methanol precipitation method. The results obtained are shown in Table 3.

Comparative Example 1 (Photopolymerization) In Example 10, except that 0.01 mol / l of 1,1-bis (t-butylperoxy) cyclohexane and benzophenone were added as photopolymerization initiators.
Polymerization was carried out according to the method described in Example 10. The results are shown in Table 3.

[0032]

[Table 3]

Examples 13 to 15 (Photocuring) Ester acrylate resin prepared by adding 2 parts each of the photocuring agents of the present invention shown in Table 4 on a glass plate [The composition is "Aronix M-8060" (Toagosei Co., Ltd.). Product, product name) / "Aronix M-5700" (product of Toa Gosei Co., product name) = 4/6], applied to a film thickness of 100 μm,
Using a conveyor-type ultraviolet curing device (condensing type), the coating film was repeatedly passed under a high-pressure mercury lamp until the surface of the coating film hardened to a pencil hardness of 4H. Table 4 shows the number of passages until curing. The energy of the light irradiated in one pass is about 80 mJ / cm ² .

Comparative Example 2 (Photocuring) The method described in Example 13 except that 2 parts of 1,1-bis (t-butylperoxy) cyclohexane and benzophenone were added as photocuring agents in Comparative Example 2. Curing was carried out according to. The results are shown in Table 4.

[0035]

[Table 4]

The results of Tables 3 and 4 above show that the peroxyketal of the present invention has effective photopolymerization initiation performance and photocuring performance.

Example 16 (Thermal Polymerization) In a glass ampoule tube having a capacity of 20 ml, 10 g of styrene containing 0.005 mol / l of the thermal polymerization initiator of the present invention shown in Table 5 was placed, and the tube was degassed in vacuum and sealed. . The ampoule tubes were each polymerized in a constant temperature oil bath at 120 ° C. for a predetermined time. Put the polymer in methanol, reprecipitate,
The polymerization conversion rate was calculated from the weight of the obtained white powder. Also, by gel permeation chromatography,
The weight average molecular weight (Mw) was measured. The results are shown in Table 5.

Comparative Example 3 (Thermal Polymerization) The same procedure as in Example 16 was repeated except that 1,1-bis (t-butylperoxy) cyclohexane was added instead of the thermal polymerization initiator of the present invention. Polymerization was performed according to the method. The results are shown in Table 5.

[0039]

[Table 5]

Example 17 (thermosetting) 30 parts of styrene solution of highly reactive iso-unsaturated polyester resin, 30 parts of calcium carbonate (manufactured by Nitto Koka Co., Ltd.) and zinc stearate (Nippon Yushi Co., Ltd.) as a releasing agent. Made)
After 1.2 parts were added and mixed well with stirring, 1.2 parts of the thermosetting agent of the present invention shown in Table 6 was added to prepare a compound. Two aluminum plates (150 x 100 x thickness 5 mm)
A rubber spacer having a thickness of 5 mm was set between the two, and two glass fiber mats (# 450) were sandwiched, a thermocouple was inserted in the center, and then the above compound was injected. Immerse this in a 140 ° C oil bath, and after reaching the maximum exothermic temperature,
It was removed from the oil bath and demolded. About it, maximum exothermic temperature (PET), time to reach PET (CT),
The Barcol hardness after cooling and the amount of residual styrene were measured. The results are shown in Table 6.

Comparative Example 4 (Thermosetting) In Example 17, instead of the thermosetting agent of the present invention,
Curing was carried out according to the method described in Example 17 except that 1,1-bis (t-butylperoxy) cyclohexane was added. The results are shown in Table 6.

[0042]

[Table 6]

Example 18 (Thermal cross-linking) Henschel mixer having a capacity of 75 l (stirring blade: standard type)
With an apparent specific gravity of 0.45 and a grain size of ASTM 30 mesh 9
20 kg of powdered polyethylene having a 9.5% pass, MI 30.5 and a density of 0.956 and 0.2 kg of the thermal crosslinking agent of the present invention shown in Table 7 were added at the same time and mixed at about 750 rpm for 2 minutes and 1500 rpm for 8 minutes. did. The obtained mixture was put in a casting mold to obtain a product by a biaxial rotation molding method.
The appearance and mechanical properties of the obtained product are shown in Table 7.

Comparative Example 5 (Thermal Crosslinking) In Example 18, instead of the thermal crosslinking agent of the present invention,
1,1-bis (t-butylperoxy) -3,3,5-
Example 18 except that trimethylcyclohexane was used.
Crosslinking was carried out according to the method described in 1. and the results are shown in Table 7.

[0045]

[Table 7]

From the results shown in Tables 5 to 7 above, it is understood that the peroxyketal of the present invention has effective performance as a thermal polymerization initiator, a curing agent and a crosslinking agent.

Examples 19 to 21 (storage stability) Ester acrylate resins (composition same as the resin used in Example 13) were prepared by adding 2 parts each of the compounds of the present invention shown in Table 8 to a glass bottle. Then, the storage stability in the dark was examined at 60 ° C. in an incubator. The storage stability in the dark was visually expressed as the number of days until gelation occurred. The results are shown in Table 8.

Comparative Examples 6 and 7 (Storage Stability) In Example 19, darkness was obtained according to the method described in Example 19 except that 2 parts each of the conventional compounds shown in Table 8 were added as compounds. The storage stability was examined.
The results are shown in Table 8.

[0049]

[Table 8] The results in Table 8 show that the peroxyketal of the present invention has good storage stability in the dark.

Claims (3)

[Claims] 1. A general formula: (In the formula, R ₁ is a tertiary alkyl group having 4 to 10 carbon atoms or a tertiary aralkyl group having 9 to 12 carbon atoms, and R ₂ is 1 to 3 carbon atoms.
4 is an alkylene group, R ₃ is an alkyl group having 1 to 2 carbon atoms, and m and n are each an integer of 0 to 2 such that m + n is an integer of 1 to 4. ) Peroxyketal represented by. 2. A general formula: (In the formula, R ₁ is a tertiary alkyl group having 4 to 10 carbon atoms or a tertiary aralkyl group having 9 to 12 carbon atoms, and R ₂ is 1 to 3 carbon atoms.
4 is an alkylene group, R ₃ is an alkyl group having 1 to 2 carbon atoms, and m and n are each an integer of 0 to 2 such that m + n is an integer of 1 to 4. ) A photodegradable radical generator containing a peroxyketal as an active ingredient. 3. A general formula: (In the formula, R ₁ is a tertiary alkyl group having 4 to 10 carbon atoms or a tertiary aralkyl group having 9 to 12 carbon atoms, and R ₂ is 1 to 3 carbon atoms.
4 is an alkylene group, R ₃ is an alkyl group having 1 to 2 carbon atoms, and m and n are each an integer of 0 to 2 such that m + n is an integer of 1 to 4. ) A heat-decomposable radical generator containing a peroxyketal as an active ingredient.