JPH0554842B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a photopolymerization initiator containing specific isophthalophenones as an active ingredient. (Prior art) Photopolymerization and curing methods that photopolymerize and photocure photopolymerizable (photocurable) monomers and photopolymerizable (photocurable) resin compositions can be rapidly polymerized and cured at low temperatures, resulting in high productivity. It has many advantages such as improved performance, energy saving, and no pollution, and it can also be selectively cured, so it is widely used in processing printing inks, paints, adhesives, printing plates, printed wiring boards, etc. Various photoinitiators have been developed for photopolymerization and photocuring methods. Among them, benzophenone and its derivatives are typical photopolymerization initiators that have long been used in the fields of printing inks and paints because they are easy to produce and relatively inexpensive. For example, 4-chlorobenzophenone, 4,4'-dichlorobenzophenone, 4-methylbenzophenone,
4,4'-Dimethylbenzophenone and 2-methoxycarbonylbenzophenone [Journal of the Oil and Color Chemists Association]
Chemists' Association) Vol. 59, pp. 166-170 (1976)], 3-methyl-4-methoxy-5'-methylbenzophenone (Japanese Unexamined Patent Publication No. 58-206605)
A typical example is (Problems to be Solved by the Invention) The above-mentioned benzophenone and its derivatives have the following drawbacks. (1) Photopolymerization activity is low and sufficient polymerization and curing rates cannot be obtained. (2) The storage stability of photopolymerizable (photocurable) monomers and photopolymerizable (photocurable) resin compositions containing benzofnonone or its derivatives is poor. (3) Odor remains in polymerized and cured products. An object of the present invention is to provide a photopolymerization initiator which has improved the above-mentioned drawbacks, is easy to produce, and has industrial value. (Means for Solving the Problems) As a result of various studies, the present inventors learned that specific isophthalofenones achieve the above object, and completed the present invention. That is, the present invention is a photopolymerization initiator containing isophthalophenones represented by the following general formula as an active ingredient. (In the formula, R is hydrogen, chlorine, bromine, _-OCH3 , or represents an alkyl group having 1 to 12 carbon atoms, n
represents an integer from 1 to 3. ) There are various isophthalophenones of the present invention as shown in the general formula above, and representative compounds thereof are listed below. (1) Isophthalofenone (2) 4′,4″-dialkyl or dicyclohexyl isophthalophenone A 4′4″-dimethylisophthalophenone (R′=CH ₃ ) B 4′4″-dimethylisophthalophenone (R′=CH ₃ ) C 4′,4″-di-n(iso)- Propylisophthalophenone (R'=n-C ₃ H ₇ , iso-C ₃ H ₇ ) 4',4''-di-n(sec, tert)-butyl isophthalophenone (R'=n- C ₄ H ₉ , sec−C ₄ H ₉ ,
tert-C ₄ H ₉ ) E 4′,4″-di-n-octylisophthalophenone (R′=n-C ₈ H ₁₇ ) F 4′,4″-di-n-dodecyl isophthalophenone (R′=C ₁₂ H ₂₅ ) 4′,4″-dicyclohexyl isophthalophenone (3) 4′,4″-dichloroisophthalophenone (4) 2′,2″,4′,4″-tetrachloroisophthalophenone (5) 4′,4″-dibromyisophthalophenone (6) 4′,4″-dimethoxyisophthalophenone (7) 3′,3″,4′,4″-tetramethylisophthalophenone (8) 2′,2″,4′,4″-tetramethylisophthalophenone (9) 2′,2″,5′,5″-tetramethylisophthalophenone (10) 2′,2″,4′,4″-tetra-isopropylisophthalophenone (11) 2′,2″,4′,4″,6′,6″-hexamethylisophthalophenone (12) 3′,3″-dimethyl-4′,4″-dimethoxyisophthalophenone (13) 3′,3″-dichloro-4′,4″-dimethylisophthalophenone The isophthalofenones of the present invention can be easily prepared by a conventional Friedel-Crafts reaction of isophthalic acid chloride and benzene or substituted benzene. The isophthalofenones of the present invention may be mixed alone into a photopolymerizable (photocurable) monomer or a photopolymerizable (photocurable) resin composition depending on the application, but usually they are aliphatic Further, an aromatic amine is used in combination. The reason is that isophthalofenones belong to hydrogen abstraction type photopolymerization initiators.
The amine acts as a hydrogen donor and efficiently promotes the photopolymerization (photocuring) reaction, resulting in photopolymerization (photocuring).
This is because it is preferable for increasing speed. Examples of amines used in combination include triethylamine, triethanolamine, tributylamine, diethanolamine, N-methyldiethanolamine, Michler's ketone, p-dimethylaminobenzoic acid, and esters thereof. Furthermore, the isophthalofenones of the present invention can be used with other known photoinitiators, such as benzophenone,
It can also be used in combination with organic peroxides such as benzoin ether, dialkoxyacetophenone, benzyl methyl ketal, thioxanthone or benzoyl peroxide. The photopolymerization initiator is a photopolymerizable (photocurable) monomer,
The photopolymerization initiator of the present invention is used by being mixed with a photopolymerizable (photocurable) resin, but at this time, commonly used additives such as pigments, fillers, dyes, and plasticizers can also be appropriately blended. Such so-called photopolymerizable (photocurable) resin compositions are used for paints, inks, adhesives, printing plates, printed wiring plates, and the like. Examples of photopolymerizable (photocurable) monomers and photopolymerizable (photocurable) resins for which the photopolymerization initiator of the present invention is used include acrylic acid, methacrylic acid, maleic acid, fumaric acid, crotonic acid, and itaconic acid. Unsaturated carboxylic acids and their derivatives, such as methyl (meth)acrylate, ethyl (meth)
Acrylate, butyl (meth)acrylate, 2
- Monoesters such as ethylhexyl (meth)acrylate, phenyl (meth)acrylate, benzyl (meth)acrylate, hydroxyalkyl esters such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, ethylene glycol Polyvalent esters such as diacrylate, polyethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tetraacrylate, vinyl acetate, vinyl propionate, vinyl acrylate , vinyl esters such as vinyl succinate, vinyl ethers, styrene, alkylstyrenes, halogenated styrenes, divinylbenzene,
Vinylnaphthalene, N-vinylpyrrolidone, diallyl phthalate, diallyl maleate, triallyl isocyanate, triallyl phosphate, (meth)acrylonitrile, (meth)acrylamide,
Various monomers such as vinyl compounds such as N-substituted (meth)acrylamide, and curable resins with maleate, fumarate, allyl, (meth)acrylate groups, unsaturated polyester resins, unsaturated acrylic resins, isocyanate modified resins, etc. quality acrylate oligomer, epoxy modified acrylic oligomer, polyester acrylic oligomer,
Examples include various resins and oligomers such as polyether acrylic oligomers. The photopolymerization initiator of the present invention is added in an amount of 0.05 to 20% by weight, preferably 0.1 to 10% by weight, based on the photopolymerizable (photocurable) monomer and photopolymerizable (photocurable) resin. Further, when an amine is used in combination, the amount added may be within the same range as that of the photopolymerization initiator. The photopolymerization initiator of the present invention may be directly blended with a photopolymerizable (photocurable) monomer or photopolymerizable (photocurable) resin, or may be blended after being dissolved in a commonly used reactive diluent such as an acrylic monomer. You may. When carrying out photopolymerization and photocuring of monomers and resins using the photopolymerization initiator of the present invention, the light source is
It only needs to contain light with a wavelength shorter than 420 nm.
Examples include sunlight, mercury lamps, hydrogen discharge tubes, xenon arc lamps, flash discharge tubes, tungsten lamps, halogen lamps, dye lasers, krypton ion lasers, and the like. (Effects of the Invention) The photopolymerization initiator isophthalophenones of the present invention have the following superior characteristics compared to conventional bezophenones and derivatives thereof. (1) As shown in their chemical structure, isophthalofenones have a wide conjugated system and excellent light absorption, so they have high photopolymerization activity and can rapidly photopolymerize and photocure monomers and resins. be able to. (2) A photopolymerizable (photocurable) resin composition containing isophthalophenone as a photopolymerization initiator has good storage stability. (3) No odor remains in polymerized or cured products. The photopolymerization initiator of the present invention has the above-mentioned characteristics, and in addition, it is easy to obtain raw materials and to manufacture, and its industrial value is extremely high. (Example) Next, the usefulness of the present invention will be explained in more detail with reference to Examples, Reference Examples, and Comparative Examples. Reference Example 1 (Production of isophthalofenones) 19.5 g (0.25 mol) of benzene, 29.4 g (0.22 mol) of anhydrous aluminum chloride, and disulfide are placed in a four-necked flask equipped with a stirrer, reflux condenser, and thermometer. 50ml of carbon was introduced. Add isophthalic acid chloride to 50mm of carbon disulfide.
A solution containing 20.3g (0.10mol) was stirred for 20 minutes.
Added portionwise at ~25°C. Then increase the reaction temperature to 45~
The temperature was raised to 47°C and the reaction continued for 60 minutes under reflux. After the generation of hydrochloric acid gas stopped, the reaction mixture was poured into 700 mm of ice water to separate the organic layer. The separated organic layer was washed twice with an equal volume of 5% aqueous caustic solution and twice with an equal volume of water, and dried over magnesium sulfate. Next, carbon disulfide was distilled off under reduced pressure, and the residue was recrystallized with methanol to obtain 27.9 g of isophthalophenone as a white solid. (Yield 97.6%) The results are shown in Table 1. Reference examples 2 to 10 Using various substituted benzenes instead of benzene,
The corresponding isophthalophenones were produced in the same manner as in Reference Example 1. Similar to Reference Example 1, the results are shown in Table 1.

【table】

[Table] Examples 1 to 12 Comparative Examples 1 to 3 (Photopolymerization of methyl methacrylate) In each example and comparative example, methyl methacrylate containing no polymerization inhibitor in a quartz photopolymerization tube, based on 100 parts by weight of methyl methacrylate , 0.2 parts by weight of each of the photopolymerization initiators shown in Table 2 and 0.2 parts by weight of triethanolamine were added, and the mixture was replaced with nitrogen by a freeze-thaw method. Next, using a merry-go-round light irradiation device (MGR-P type, manufactured by Taishina Kogyo Co., Ltd.) in a constant temperature bath at 20°C,
Toshiba glass filter UVD36 for 400W high pressure mercury lamp
-A and irradiated with light for 30 minutes using a mercury lamp with a dominant wavelength of irradiation light of 365 nm for polymerization. Thereafter, polymethyl methacrylate was collected by a methanol precipitation method, and the polymerization conversion rate was measured by a gravimetric method, and the polymerization rate was calculated. The results are shown in Table 2.

【table】

Table 2 shows that the photopolymerization initiator of the present invention has higher photopolymerization activity than conventional products and can be rapidly photopolymerized. Examples 13 to 25 Comparative Examples 4 to 8 (Photocuring of photocurable resin composition) (1) Preparation of resin composition Using commercially available photopolymerizable monomers and photocurable resins, each was prepared in the following formulations. A resin composition was prepared. (A) Ester acrylate resin composition Aronix M-8060 (Toagosei Chemical Industry Co., Ltd.)
40 parts by weight Aronix M-5700 (Toagosei Chemical Industry Co., Ltd.)
60 parts by weight (B) Urethane acrylate resin composition Aronix M-1100 (Toagosei Chemical Industry Co., Ltd.)
) 50 parts by weight Tetrahydrofurfuryl acrylate
25 parts by weight 2-hydroxyethyl methacrylate
25 parts by weight (C) Epoxy acrylate resin composition Lipoxy SP-1509 (manufactured by Showa Kobunshi Co., Ltd.)
50 parts by weight trimethylolpropane triacrylate
20 parts by weight Ethyl carbitol acrylate 20 parts by weight N-vinylpyrrolidone 10 parts by weight (2) Photocuring test In each example and comparative example, based on 100 parts by weight of the photocurable resin composition prepared in (1) above, Third
Add and dissolve 2 parts by weight of each of the photopolymerization initiators shown in the table and 1 part by weight of triethanolamine, apply the film to a thickness of 100 μm on a glass plate, and use a condensing conveyor type ultraviolet irradiation device (Nippon Battery Co., Ltd.). The curing speed was determined using a predetermined conveyor speed and irradiation distance. The light source used was a single 2KW (80W/cm) ozone type high-pressure mercury lamp, and the curing speed was expressed as the number of passes under the light source required for the membrane surface to become touch-free. this
The smaller the number of passes, the faster the curing speed. The results are shown in Table 3.

【table】

[Table] All residual odors from the final stage were odorless except for benzophenone. As is clear from Table 3, the photopolymerization initiator of the present invention has a faster curing speed than conventional photopolymerization initiators. This means that in practical use it is possible to increase line speed, that is, to improve productivity per unit time, and is extremely useful industrially. Examples 26 to 33 Comparative Examples 9 to 14 In each Example and each Comparative Example, Aronix M-
An ester acrylate resin composition was prepared by blending 40 parts by weight of 8060 (manufactured by Toagosei Kagaku Kogyo Co., Ltd.) and 60 parts by weight of Aronix M-5700 (manufactured by Toagosei Kagaku Kogyo Co., Ltd.). A predetermined amount of the photopolymerization initiator shown in Table 4 (combined with triethanolamine if necessary) was added and dissolved in this resin composition, and the curing speed was determined in the same manner as in Examples 13 to 25. . The irradiation distance is
15 cm, and the conveyor speed was 10 m/min. The results are shown in Table 4.

【table】

[Table] As is clear from Table 4, the photopolymerization initiator of the present invention has a faster curing speed than conventional photopolymerization initiators, and even when used alone, the photopolymerization initiator of the present invention has a significantly higher curing speed than conventional photopolymerization initiators. It turns out that it is excellent. Examples 34 to 40 Comparative Examples 15 to 19 (Storage stability test) In each of the Examples and Comparative Examples, Aronix M-
An ester acrylate resin composition was prepared by blending 40 parts by weight of 8060 (manufactured by Toagosei Kagaku Kogyo Co., Ltd.) and 60 parts by weight of Aronix M-5700 (manufactured by Toagosei Kagaku Kogyo Co., Ltd.). A resin composition in which a predetermined amount of the photopolymerization initiator and triethylamine or triethanolamine shown in Table 5 were added and dissolved was prepared in a dark place.
The mixture was left at 60°C and the number of days until gelation was determined was determined. The results are shown in Table 5.

【table】

[Table] Represents parts by weight.
As is clear from Table 5, the resin composition containing the photopolymerization initiator of the present invention has extremely excellent storage stability.

Claims (1)

[Claims] 1. General formula (In the formula, R is hydrogen, chlorine, bromine, _-OCH3 , or represents an alkyl group having 1 to 12 carbon atoms, n
represents an integer from 1 to 3. ) A photopolymerization initiator containing isophthalofenones as an active ingredient.