JPH04225002A - Photo-polymerization initiator - Google Patents

Abstract

PURPOSE:To provide a photo-polymerization initiator containing a specific coumarin derivative having fluoroalkyl group and a polyvalent peroxy ester having benzophenone group and having high sensitivity, light-transmittance, curing depth, fastness and safety. CONSTITUTION:The objective photo-polymerization initiator usable even with light of visible range can be produced by compounding (A) a coumarin derivative having fluoroalkyl group and expressed by formula I (X is F, Cl or H; R1 is H or 1-4C alkyl; R2 is 1-4C dialkylamino; (n) is integer of 1-10) (e.g. 3- trifluoromethyl-7-diethylaminocoumarin) and (B) a polyvalent peroxy ester having benzophenone group and expressed by formula II (R3 and R5 are 4-8C tert. alkyl or 9-12C tert. aralkyl; R4 and R6 are H, 4-8C tert. alkoxy or 9-12C tert. aralkyloxy) [e.g. 3,3',4,4'-tetra-(t-butylperoxycarbonyl)benzophenone].

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photopolymerization initiator for polymerizing ethylenically unsaturated compounds, and more particularly to a photopolymerization initiator sensitive to light in the wavelength range of 300 to 600 nm, including visible light.

0002

BACKGROUND OF THE INVENTION It is known that monomers, dimers, trimers, oligomers and polymers containing ethylenically unsaturated bonds in their molecules are photopolymerized in the presence of a photopolymerization initiator. This phenomenon is caused by paints, adhesives, printing inks, printing plates,
It is used in printed wiring boards, and recently it is being applied to medical fields such as dental resins.

Conventionally, various substances have been reported and actually used as photopolymerization initiators, including benzoin compounds such as benzoin, benzoin methyl ether, and benzoin ethyl ether; benzyl, benzophenone, acetophenone, and Michler's ketone. Carbonyl compounds such as; azo compounds such as azobisisobutyronitrile and azodibenzoyl; dibenzothiazolyl sulfide,
Sulfur compounds such as tetraethylthiuram disulfide; halogen compounds such as carbon tetrachloride and tribromphenyl sulfone; 1,2-benzanthraquinone and the like are used. Further, as an initiator containing benzophenone polyhydric peroxy esters, one in combination with a coumarin dye has been proposed.

0004

However, most of the photopolymerization initiators do not have sensitivity in the visible region. For example, JP-A-61-158908 discloses a photopolymerization initiator characterized by containing a benzophenone-containing polyhydric peroxyester.
Although polymerization systems using the photopolymerization initiators exhibit high sensitivity in the ultraviolet region, they have the drawback of being almost insensitive to the visible region. On the other hand, JP-A No. 63-23901 proposes a photopolymerization initiator that is sensitive to the visible region and is a combination of a benzophenone-containing polyvalent peroxyester and a coumarin dye. However, the photopolymerization initiator is difficult to manufacture because the coumarin dye has a complex substituent such as a heterocycle such as a benzimidazoyl group or a 4-ethoxycinnamoyl group at the 3-position. , and has a problem of poor fastness.

The object of the present invention is to provide a highly sensitive photopolymerization initiator that initiates photopolymerization by being sensitive to light in a wide range of wavelengths including visible light, and that has a deep curing depth and high fastness through photopolymerization. is intended to provide.

[0006]

[Means for Solving the Problems] According to the present invention, the following general formula 3 (wherein , R2 represents a dialkylamino group having 1 to 4 carbon atoms, and n represents an integer of 1 to 10) (hereinafter referred to as coumarin derivative A);

[0007]

[Formula 3] The following general formula 4 (wherein R3 and R5 each represent a tertiary alkyl group having 4 to 8 carbon atoms or a tertiary aralkyl group having 9 to 12 carbon atoms, R4 and R6 each represent a hydrogen atom, benzophenone-containing polyvalent peroxyesters (hereinafter referred to as polyvalent peroxyesters B) represented by a tertiary alkoxy group having 4 to 8 carbon atoms or a tertiary aralkyloxy group having 9 to 12 carbon atoms. A photopolymerization initiator is provided.

[0008]

[C4] The present invention will be explained in detail below.

The photopolymerization initiator of the present invention is characterized in that it contains the coumarin derivative A and the polyhydric peroxyester B.

Specific examples of the coumarin derivative A used in the photopolymerization initiator of the present invention include 3-trifluoromethyl-7-diethylaminocoumarin, 3-trifluoromethyl-7-dimethylaminocoumarin, and 3-trifluoromethyl-7-dimethylaminocoumarin. Trifluoromethyl-4-methyl-7-diethylaminocoumarin, 3-trifluoromethyl-4-methyl-7-dimethylaminocoumarin, 3-heptafluoropropyl-4
-Methyl-7-diethylaminocoumarin, 3-heptafluoropropyl-4-methyl-7-dimethylaminocoumarin, 3-pentafluoroethyl-4-methyl-7-diethylaminocoumarin, 3-pentafluoroethyl-4
-Methyl-7-dimethylaminocoumarin, 3-tridecafluorohexyl-4-methyl-7-diethylaminocoumarin, 3-tridecafluorohexyl-4-methyl-
7-dimethylaminocoumarin, 3-pentadecafluoroheptyl-4-methyl-7-diethylaminocoumarin,
3-Pentadecafluoroheptyl-4-methyl-7-dimethylaminocoumarin, 3-difluoromethyl-4-methyl-7-diethylaminocoumarin, 3-difluoromethyl-4-methyl-7-dimethylaminocoumarin, 3-
Preferred examples include chlorodifluoromethyl-4-methyl-7-diethylaminocoumarin and 3-chlorodifluoromethyl-4-methyl-7-dimethylaminocoumarin, which can be used alone or as a mixture.

To prepare the coumarin derivative A, for example, when preparing 3-heptafluoropropyl-4-methyl-7-dimethylaminocoumarin, 4-methyl-7
It can be easily obtained by a method in which 1 mole of -dimethylaminocoumarin and 1 mole of bis(heptafluorobutyryl) peroxide are reacted in methylene chloride or the like as a solvent, preferably under reflux for 3 to 10 hours.

Further, in the photopolymerization initiator of the present invention, the polyhydric peroxyesters B used together with the coumarin derivative A include, for example, 3,3',4,4
'-Tetra-(t-butylperoxycarbonyl)benzophenone, 3,3',4,4'-tetra-(t-amylperoxycarbonyl)benzophenone, 3,3',
4,4'-tetra-(t-hexylperoxycarbonyl)benzophenone, 3,3',4,4'-(t-tetraoctylperoxycarbonyl)benzophenone, 3
, 3',4,4'-tetra-(cumylperoxycarbonyl)benzophenone, 3,3',4,4'-tetra-
(p-isopropylcumylperoxycarbonyl)benzophenone, 3,3'-di(t-butylperoxycarbonyl)-4,4'-di(carboxy)benzophenone, 3,3'-di(t-hexylperoxycarbonyl)
Preferred examples include -4,4'-di(carboxy)benzophenone, which can be used alone or as a mixture.

[0013] In order to prepare the polyhydric peroxyesters B, for example, 3,3',4,4'-tetra-(t-
When preparing benzophenone (butylperoxycarbonyl), 1 mole of 3,3',4,4'-tetra(chloroformyl)benzophenone and 4 moles of t-butyl hydroperoxide are mixed in a solution such as an alkaline aqueous solution, preferably from 0 to It can be obtained by a method of reacting at 40°C for 1 to 10 hours.

In the present invention, the mixing ratio of the coumarin derivative A and the polyvalent peroxyesters B is such that the weight ratio is coumarin derivative A: polyvalent peroxyesters B=
The ratio is preferably 1-99:99-1, particularly preferably 5-90:95-10. If the blending ratio is outside the range, excellent effects cannot be obtained, which is not preferable.

To prepare the photopolymerization initiator of the present invention, the coumarin derivative A and the polyhydric peroxyester B
In addition to the above-mentioned essential components, for example, pigments, fillers, pigments,
Additives such as sensitizers, thermal polymerization inhibitors, plasticizers, solvents, binders, etc. can also be blended as appropriate.

The photopolymerization initiator of the present invention can be preferably used in polymerizing ethylenically unsaturated compounds. Examples of the ethylenically unsaturated compound include all monomers, dimers, trimers, oligomers, and polymers containing ethylenically unsaturated bonds in their molecules, such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, Unsaturated carboxylic acids such as crotonic acid and itaconic acid and the aforementioned unsaturated carboxylic acid derivatives; methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, phenyl (meth)acrylate , monoesters such as benzyl (meth)acrylate; hydroxyalkyl esters such as 2-hydroxyethyl (meth)acrylate; ethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate,
Neopentyl glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythrtetra(meth)acrylate, 2,2'-
Polyvalent esters such as bis[4-(3-methacryloxy-2-hydropropoxy)phenyl]propane; (meth)
acrylonitrile, (meth)acrylamides and N-substituted (meth)acrylamides; vinyl esters such as vinyl acetate, vinyl propionate, vinyl acrylate and vinyl succinate; vinyl ethers; styrene, alkylstyrenes, halogenated styrenes, N-
Vinyl compounds such as vinylpyrrolidone, diacrylphthalate, diallyl maleate, triallyl isocyanate, and triallyl phosphate; Curable resins having fumarate, maleate, allyl, and (meth)acrylate groups; Unsaturated polyester; Unsaturated Preferred examples include acrylic resins; isocyanate-modified acrylate oligomers; epoxy-modified oligomers; polyester acrylic oligomers; polyether acrylic oligomers, and can be used alone or as a mixture.

To use the photopolymerization initiator of the present invention, for example, the photopolymerization initiator of the present invention is mixed with the ethylenically unsaturated compound, etc., and photopolymerized and photocured by irradiating it with light. I can do it.

The amount of the photopolymerization initiator of the present invention used in the photopolymerization or photocuring is 0.01 to 40 parts by weight, particularly preferably 0.1 parts by weight, based on 100 parts by weight of the ethylenically unsaturated compound. -20 parts by weight. When the amount of the photopolymerization initiator used is less than 0.01 parts by weight, the polymerization progresses insufficiently, and when it exceeds 40 parts by weight,
This is not preferable because there is a risk that the light transmittance will decrease or that unreacted initiator may remain, resulting in deterioration of the physical properties of the polymer. Further, the light irradiated for photopolymerization or photocuring preferably has a wavelength of 300 to 600 nm. In addition, all light sources that can be used at this time include those that emit light with a wavelength within the above range, such as sunlight, mercury lamps, hydrogen discharge tubes, xenon lamps, flash discharge tubes,
Preferred examples include tungsten lamps, halogen lamps, metal halide lamps, and lasers.

[0019]

Effect of the invention: The photopolymerization initiator of the present invention has a wavelength of 300~
Ethylenically unsaturated compounds, etc. can be polymerized and cured by exposure to light in the 600 nm range, and the resulting polymerized cured product has excellent light transparency and a deep curing depth, making it suitable for paints, adhesives, and printing. It can be used for polymerization and curing of inks, printing plates, printed wiring boards, dental resins, etc., as well as for polymerization and curing of thick films and molded bodies. In addition, the photopolymerization initiator of the present invention has high sensitivity, so it is excellent in terms of workability and economy, and can also be used with light in the visible region, and has excellent fastness when exposed to light. It is also excellent in terms of safety because it is difficult to disassemble.

[0020]

EXAMPLES The present invention will be explained in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

[0021]

Examples 1 to 9 Fluoroalkyl group-containing coumarin derivatives and peroxy esters shown in Table 1 were mixed in the proportions shown in Table 1 to prepare polymerization initiators. Next, the obtained photopolymerization initiator was added and dissolved in the ethylenically unsaturated compounds shown in Table 1 to prepare a photosensitive solution. The obtained photosensitive liquid was filled into a polyethylene cylinder with an inner diameter of 10 mm and a depth of 8.5 mm, and a halogen lamp (15V-1
5W) was used for polymerization and curing by irradiation with light. Example 3,
In order to clarify the effect of radiation wavelength in 6, 7 and 9,
A colored glass filter (trade name "L-42" or "Y-45", both manufactured by Toshiba Glass Co., Ltd.) was installed at the top of the cylinder, and light was irradiated with the halogen lamp to effect polymerization and curing.

[0022] The irradiance at the top of the cylinder when no colored glass filter was installed was 50 mW/cm2 when measured using an ebre samopile, but when a colored glass filter was installed, the irradiance was 1/2 to 1/2. It decreased to 3 or less. The initiation efficiency of the photopolymerization initiator was determined by measuring the curing depth of the photosensitive liquid using a micrometer after removing the polymerized and cured product. The results are shown in Table 1.

[0023]

[Table 1] As is clear from the results in Table 1, the photopolymerization initiator of the present invention efficiently polymerizes and cures ethylenically unsaturated compounds by irradiation with visible light for a short period of about 30 to 90 seconds using a halogen lamp. Furthermore, it was found that a cured product with a deep curing depth could be obtained due to its excellent light transmittance. In addition, the results obtained when a colored glass filter was installed showed that although the radiation intensity was reduced to 1/2 to 1/3, polymerization and curing could be effectively performed even with long wavelength light.

[0024]

Comparative Examples 1 to 3 Photosensitive solutions were prepared and tested in the same manner as in Examples 1 to 9, except that the photopolymerization initiators and ethylenically unsaturated compounds shown in Table 2 were used. The results are shown in Table 2.

[0025]

[Table 2] As is clear from the results shown in Table 2, fluoroalkyl group-containing coumarin derivatives alone do not polymerize and cure at all, and when benzophenone-containing polyvalent peroxyesters are used alone as photopolymerization initiators, visible light It had no sensitivity at all. Moreover, coumarin derivatives containing no fluoroalkyl group had almost no sensitivity to visible light of 450 nm.

[0026]

[Example 10 and Comparative Example 4] Polymerization was started by mixing 1.0 parts by weight of each of the coumarin derivatives shown in Table 3 and 3,3',4,4'-tetra-(t-butylperoxycarbonyl)benzophenone. A drug was prepared. Then, the obtained photopolymerization initiator was added and dissolved in 100 parts by weight of triethylene glycol dimethacrylate to prepare a photosensitive liquid. The obtained photosensitive liquid was cast into a stainless steel mold with an inner diameter of 30 mm and a depth of 0.3 mm, and a halogen lamp (10
0V-150W) was irradiated with light for 10 minutes using four lamps for polymerization and curing. In the obtained film with a thickness of 0.3 mm,
The light resistance of coumarins was evaluated. Light resistance was evaluated by irradiating light with three 10W chemical lamps at room temperature and determining the decomposition rate of the coumarin derivative at that time. The results are shown in Table 3.

[0027]

[Table 3] As is clear from the results shown in Table 3, coumarin derivatives that do not contain fluoroalkyl groups are decomposed by approximately 40% after 90 minutes of light irradiation, whereas the decomposition rate of coumarins containing fluoroalkyl groups is was less than 10%. This shows that by introducing a fluoroalkyl group into coumarins, the light resistance is significantly increased and the coumarins have high fastness.

Claims (1)

[Claims] Claim 1: The following general formula 1 (wherein X represents a fluorine atom, a chlorine atom, or a hydrogen atom, R1 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R2 represents a
-4 dialkylamino group is shown. In addition, a fluoroalkyl group-containing coumarin derivative represented by the following general formula 2 (wherein R3 and R5 are each a tertiary alkyl group having 4 to 8 carbon atoms) or a tertiary aralkyl group having 9 to 12 carbon atoms, R4 and R6 each represent a hydrogen atom, a tertiary alkoxy group having 4 to 8 carbon atoms, or a tertiary aralkyloxy group having 9 to 12 carbon atoms) A photopolymerization initiator characterized by containing a benzophenone-containing polyhydric peroxyester. [Case 2]