JPH04173804A - Photopolymerization initiator - Google Patents

Abstract

PURPOSE:To obtain the title initiator containing specific substituted aromatic amines, benzophenone-containing polyvalent peroxy ethers and alpha-diketone, having excellent surface curing property and light transmissivity, and capable of providing a cured product deeply cured and being sensitized to a wide range of wave lengths. CONSTITUTION:A substituted aromatic amine expressed by formula I (R1 and R2 are H or lower alkyl; R3 is alkyl, ester residue, acyl, etc.) is combined with a benzophenone-containing polyvalent peroxyester expressed by formula II (R4 and R6 are 4-8C tert. alkyl or 9-12C tert. aralkyl; R5 and R7 are H, 4-8C tert. alkoxy or 9-12C tert. aralkyloxy) and an alpha-diketone expressed by formula III [R8 and R9 are (substituted) hydrocarbons or together may form a condensed aromatic ring structure] to provide the objective photopolymerization initiator for ethylenic unsaturated compound.

Description

Detailed Description of the Invention <Industrial Application Field> The present invention relates to a photopolymerization initiator for the polymerization of ethylenically unsaturated compounds, and more specifically to a photopolymerization initiator for the polymerization of ethylenically unsaturated compounds, and more specifically
This invention relates to a photopolymerization initiator that is sensitive to light in the n@ range.

<Conventional technology> A hexamer containing an ethylenically unsaturated bond in its molecule.

It is known that dimers, trimers, oligomers and polymers photopolymerize in the presence of photoinitiators. This phenomenon is used in paints, adhesives, printing inks, printing plates, printed wiring plates, etc., and has recently been applied to medical fields such as dental resins.

Conventionally, various substances have been reported and actually used as the photopolymerization initiator, and specifically, for example, benzoin compounds such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzyl, benzophenone, acetophenone, Carbonyl compounds such as Michler's ketone, azo compounds such as azobisisobutyronitrile and azodibenzoyl, sulfur compounds such as dibenzothiazolyl sulfide and tetrathiuram disulfide, halogen compounds such as carbon tetrachloride and tribromphenyl sulfone, 1
, 2-benzanthraquinone, etc.

- Furthermore, as photopolymerization initiators containing benzophenone polyhydric peroxy esters, those in combination with thiopyrylium salts or α-diketones have been proposed.

However, since the polymerization of ethylenically unsaturated compounds using the photopolymerization initiator is a radical polymerization, it is easily inhibited by oxygen in the air, and in order to improve surface curing properties, it is necessary to increase the intensity of light irradiation. Problems include the need to increase the size, increase the initiator concentration, or lengthen the irradiation time.

For example, in Japanese Patent Application Laid-Open No. 61-197505,
A photopolymerization initiator characterized by containing benzophenone polyhydric peroxyesters and α-diketones has been disclosed, but a polymerization system using the photopolymerization initiator has high sensitivity in the visible region. However, photopolymerization initiators characterized by being susceptible to polymerization inhibition by oxygen and containing benzoin alkyl ethers have also been proposed, but in photopolymerization systems using the photopolymerization initiators,
There are problems in that no activity is observed in visible light and polymerization is easily inhibited by oxygen.

<Problems to be Solved by the Invention> Therefore, an object of the present invention is to develop a material that initiates photopolymerization by being exposed to light of a wide range of wavelengths including the visible light region, is less susceptible to polymerization inhibition by oxygen, and has excellent surface hardening properties. , deep curing depth,
Another object of the present invention is to provide a highly sensitive photopolymerization initiator.

<Means for Solving the Problems> According to the present invention, the following general formula (I) Ks (wherein R□ and R2 are the same or different groups and represent a hydrogen atom or a lower alkyl group, R3 represents an alkyl group, an ester residue, an acyl group, or a benzoyl group)
Substituted aromatic amines represented by the following general formula (II) (wherein R4 and R6 each represent a tertiary alkyl group having 4 to 8 carbon atoms or a tertiary aralkyl group having 9 to 12 carbon atoms, and R9 and R7 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), and benzophenone-containing polyhydric peroxyesters represented by the following general formula (m ) (In the formula, R8 and R9 each represent a hydrocarbon group or a substituted hydrocarbon group, and each may be bonded directly or via a divalent hydrocarbon group or a substituted hydrocarbon group,
Further, there is provided a photopolymerization initiator characterized by containing an α-diketone represented by R8 and R9 may be combined to form a fused aromatic ring structure.

The present invention will be explained in detail below.

The photopolymerization initiator of the present invention comprises a specific substituted aromatic amine,
It is characterized by containing a specific benzophenone-containing polyhydric peroxyester and a specific α-diketone.

The substituted aromatic amines used in the photopolymerization initiator of the present invention can be represented by the following general formula (1), where R and R2 are the same or different groups,
It represents a hydrogen atom or a lower alkyl group, and R1 represents an alkyl group, an ester residue, an acyl group, or a benzoyl group. Specifically, the substituted aromatic amines represented by the general formula (1) include, for example, N,N-diethylbenzoic acid, N
, N-dimethylbenzoic acid, N,N-ethyl-N-dimethylbenzoate.

Ethyl N-diethylbenzoate, Isoamyl N,N-dimethylbenzoate, 2-ethylhexyl N,N-dimethylbenzoate, N,N-dimethylacetophenone, N,N-diethylacetophenone, N.

N-dimethylbenzophenone, N,N-diethylbenzophenone, N,N-dimethylpara-toluidine, N,N-
Preferred examples include diethyl para-toluidine, N,N-dimethylbenzaldehyde, and 4,4'-bis-(dimethylamino)benzophenone, which may be used alone or as a mixture. Further, the maximum absorption wavelength of the substituted aromatic amines is 300 to 7
It is preferably in the range of 00n■.

To prepare the substituted aromatic amines, for example, N,
When preparing ethyl N-dimethylaminobenzoate, N
, can be easily obtained by reacting N-dimethylaminobenzoic acid chloride and ethyl alcohol by a conventional method, or a commercially available product can also be used.

Furthermore, the benzophenone group-containing polyhydric peroxyesters used in the photopolymerization initiator of the present invention have the following general formula (n
), in which R4 and R8 each represent a tertiary alkyl group having 4 to 8 carbon atoms or a tertiary aralkyl group having 9 to 12 carbon atoms, and R1 and R7 each represent a hydrogen atom or a tertiary aralkyl group having 9 to 12 carbon atoms. Tertiary alkoxy group having 4 to 8 carbon atoms or having 9 to 9 carbon atoms
12 represents a tertiary aralkyloxy group. Said R4 and R
, is a tertiary alkyl group having 9 or more carbon atoms, or R6 and R7 are tertiary alkoxy groups having 9 or more carbon atoms, or R4 and R,
is a tertiary aralkyl group having 13 or more carbon atoms or R6 and R7
is a tertiary aralkyloxy group having 13 or more carbon atoms, production is difficult. Examples of the benzophenone-containing polyhydric peroxyesters represented by the general formula (n) include 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'-tetra -(t-octylperoxycarbonyl)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)-4,4'-
Preferred examples include di(carboxy)benzophenone, which can be used alone or as a mixture.

To prepare the benzophenone-containing polyhydric peroxy esters, for example, 3.3', 4°4'-tetra-
3.3' when preparing (t-butylperoxylponyl)benzophenone.

It can be easily obtained by reacting 4,4'-tetra(chloroformyl)benzophenone and t-butyl hydroperoxide in an alkaline aqueous solution by a conventional method, or a commercially available product can also be used.

Further, the α-diketone used in the photopolymerization initiator of the present invention can be represented by the following formula (m), where R0 and R9 each represent a hydrocarbon group or a substituted hydrocarbon group, and each of them can be directly Alternatively, they may be bonded via a divalent hydrocarbon group or a substituted hydrocarbon group, or R1 and R9 may be bonded to form a fused aromatic ring structure. Examples of the α-diketone include biacetyl, 2,3-pentadione, 2,3-octadione, benzyl, 4,4'-dimethoxybenzyl, 4,4'
-dichlorobenzyl, acenaphthenequinone, 9.10-
Preferred examples include phenanthrenequinone, camphorquinone, and β-naphthoquinone, which can be used alone or as a mixture.

In the present invention, the blending ratio of the substituted aromatic amine, the benzophenone-containing polyhydric peroxyester, and the α-diketone is 1% by weight, preferably 0.1 to 99% by weight.
．． 8:0.1-99.8: 0.1-99.8, particularly preferably 1-89:10-98:1-89.

If the blending ratio is outside the above range, it is not preferable because the desired excellent effects of the present invention cannot be obtained.

The photopolymerization initiator of the present invention can be easily prepared by mixing the substituted aromatic amines, benzophenone-containing polyhydric peroxyesters, and α-diketones. At this time, in addition to the above-mentioned essential ingredients, for example, facial weight, fillers, dye-sensitizers, thermal polymerization inhibitors, plasticizers, solvents,
Additives such as binders may also be blended as appropriate.

The photopolymerization initiator of the present invention can be preferably used when polymerizing ethylenically unsaturated compounds and the like. 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 derivatives of said unsaturated carboxylic acids, such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate
Acrylate, 2-ethylhexyl (meth)acrylate, phenyl (meth)acrylate, benzyl (meth)
Monoesters such as 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'-bis(
Polyvalent esters such as 4-(3-methacryloxy-2-hydropropoxy)phenyl]propane; (meth)acrylonitrile, (meth)acrylamide and N-1!
Vinyl esters such as vinyl acetate, vinyl propionate, vinyl acrylate and vinyl succinate; Vinyl ethers; Styrene, alkyl styrene, halogenated styrene, N-vinylpyrrolidone, diacrylphthalate, diallyl maleate , vinyl compounds such as triallyl isocyanate and triallyl phosphate; curable resins having fumarate groups, maleate groups, allyl groups, and (meth)acrylate groups; unsaturated polyesters: unsaturated acrylic resins; isocyanate-modified acrylate oligomers; polyesters Acrylic oligomer; polyether acrylic oligomer,
Preferred examples include epoxy-modified acrylate oligomers, which 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 may be added to and mixed with the ethylenically unsaturated compound, etc., and the photopolymerization initiator of the present invention may be photopolymerized and photocured by irradiation with light. can.

The amount of the photopolymerization initiator of the present invention used during the photopolymerization or photocuring is preferably 0.01 to 40 parts by weight, particularly preferably 0.1 to 40 parts by weight, based on 100 parts by weight of the ethylenically unsaturated compound. The range is 20 parts by weight. When the amount of the photopolymerization initiator used is less than 0.01 parts by weight, polymerization progresses insufficiently, and when it exceeds 40 parts by weight, light transmittance decreases and unreacted This is not preferable because the agent remains and the physical properties of the polymer deteriorate. Further, the wavelength of the light irradiated to perform the photopolymerization or photocuring is 300 to 7
A range of 00 nm is preferred. In addition, any light source that can be used in this case can be used as long as it emits light with a wavelength within the above range, such as sunlight, mercury lamps,
Preferred examples include hydrogen discharge tubes, canon lamps, flash discharge tubes, tungsten lamps, halogen lamps, metal halide lamps, and lasers.

<Effects of the Invention> The photopolymerization initiator of the present invention can polymerize and cure ethylenically unsaturated compounds by being exposed to light in the wavelength range of 300 to 700 nm, and the resulting polymerized cured product has surface curable properties. It has excellent light transmittance and deep curing depth, so
Paints, adhesives, printing inks, printing boards, printed wiring boards,
It is useful in polymerizing and curing dental resins, etc., and is also capable of polymerizing and curing thick films and molded bodies. In addition, the photopolymerization initiator of the present invention has higher sensitivity than conventional ultraviolet initiators, so it is superior in terms of workability and economy, and it is also safe because visible light, which is harmless to the human body, can be used. It is also excellent in this respect.

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

Substituted aromatic amines, benzophenone-containing polyhydric peroxyesters, and α-diketones shown in Table 1 were mixed in the proportions shown in Table 1 to prepare a photopolymerization initiator. Next, the obtained photopolymerization initiator was added and dissolved in a mixture of 100 parts by weight of dipentaerythritol hexaacrylate and 100 parts by weight of methyl methacrylate to obtain a photopolymerization composition. The obtained photopolymerizable composition was applied to a commercially available acrylic plate using a bar coater so that the cured film had a thickness of 20AL11, and then was irradiated with light using a halogen lamp for 5 minutes so that the average illuminance was 20 mW/cd. After completing the light irradiation, the pencil hardness of the coated film surface was measured according to JIS K5400 to evaluate surface hardening properties. Similarly, the reduction rate (%) of double bonds in the monomer before and after 3 minutes of light irradiation was measured by infrared absorption spectroscopy.
It was determined by measuring the change in absorption of 0as-1, and this value was taken as the conversion rate of 7-mer. The results are shown in Table 1.

Examples 1 to 8 except that the photopolymerization initiator was prepared by mixing the substituted aromatic amines, benzophenone-containing polyhydric peroxyesters, and α-diketones in the proportions shown in Table 1.
Each test was conducted in the same manner.

From the results shown in Table 1, the photopolymerization initiator of the present invention that lacks any one of the substituted aromatic amines, benzophenone-containing polyhydric peroxyesters, and α-diketones used in the photopolymerization initiator of the present invention It was found that the polymerizability was clearly inferior to that of the agent. Therefore, it can be seen that the photopolymerization initiator of the present invention improves the surface curability of the resulting cured product.

A photopolymerization initiator was prepared by mixing substituted aromatic amines, benzophenone-containing polyhydric peroxyesters, and α-diketones at the blending ratios shown in Table 2. Next, the obtained photopolymerization initiators were dissolved in each of the ethylenically unsaturated compounds shown in Table 2 to obtain a photosensitive solution. The obtained photosensitive liquid was filled into a polyethylene cylinder having an inner diameter of 10 cm and a depth of 10 cm, and was polymerized and cured by irradiating light from the top of the cylinder with a halogen lamp (15V-15W). Also, Examples 10 and 11゜1
3. In order to clarify the effect of the radiation wavelength in 3.14 and 17, a colored glass filter (trade name: rL-39J, rL-42J or rY-45J manufactured by Toshiba Glass Co., Ltd.) shown in Table 1 was placed on the top of the cylinder. The halogen lamp was installed and irradiated with light using the halogen lamp.

When the irradiance at the top of the cylinder without a colored glass filter was measured using an ebre samopile, it was 50 mW/aJ, 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 2.

As is clear from the results shown in Table 2, the photopolymerization initiator of the present invention can efficiently polymerize and cure ethylenically unsaturated compounds by irradiation with visible light for a short period of about 15 to 30 seconds using a halogen lamp. It was also 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 or less, even long wavelength light could effectively polymerize and cure.

Photopolymerization compositions were prepared and tested in the same manner as in Examples 1 to 8, except that the photopolymerization initiators and ethylenically unsaturated compounds shown in Table 3 were used. The results are shown in Table 3.

From the results of Comparative Examples 7 to 9, when substituted aromatic amines are replaced with tertiary amines and benzophenone-containing polyhydric peroxyesters are replaced with benzophenone or peroxyesters, the polymerizability is clearly higher than that of the photopolymerization initiator of the present invention. It turns out that it is inferior.

Moreover, from the results of Comparative Examples 10 to 13, if any one of the constituent components of the photopolymerization initiator of the present invention is missing, the polymerization property is clearly inferior to that of the photopolymerization initiator of the present invention. I understand.

(Margin below)

Claims (1)

[Claims] The following general formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(I) (In the formula, R_1 and R_2 are the same or different groups and represent a hydrogen atom or a lower alkyl group. , R_3 represents an alkyl group, ester residue, acyl group, or benzoyl group) and the following general formula (II) ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(II) (Formula R_4 and R_5 each represent a tertiary alkyl group having 4 to 8 carbon atoms or a tertiary aralkyl group having 9 to 12 carbon atoms, and R_5 and R_7 each represent a hydrogen atom or a tertiary alkoxy group having 4 to 8 carbon atoms. or a tertiary aralkyloxy group having 9 to 12 carbon atoms), and the following general formula (III) ▲There are numerical formulas, chemical formulas, tables, etc.▼...(III) (in the formula R_8 and R_9 each represent a hydrocarbon group or a substituted hydrocarbon group, and each may be bonded directly or via a divalent hydrocarbon group or a substituted hydrocarbon group, and R_8 and R_9 may be bonded together. A photopolymerization initiator characterized by containing an α-diketone (which may form a fused aromatic ring structure).