JPH0391753A - Photopolymerization initiator - Google Patents

Abstract

PURPOSE:To obtain a photopolymerization initiator capable of initiating photolymerization by responding to lights in a wide range of wavelengths, superior in surface hardenability, large in hardening depth, and good in sensitivity by incorporating an aromatic amine and a polyvalent peroxyester containing benzophenone, each specified in structure. CONSTITUTION:The photopolymerization initiator of this invention contains one of the substituted aromatic amines represented by general formula I and one of the polyvalent peroxyesters each containing benzophenones represented by general formula II. This photopolymerization initiator can be prepared by mixing said amine with said peroxyester, and at that time, a pigment, a filler, a dye, a sensitizer, a heat polymerization inhibitor, a plasticizer, a solvent, a binder, the like can be added in addition.

Description

Detailed Description of the Invention Industrial Field of Application The present invention relates to a photopolymerization initiator used for polymerizing ethylenically unsaturated compounds, and more specifically,
It relates to a photopolymerization initiator sensitive to light in the range of ~700 nm.

Prior Art> It is known that monomer dimers, trimers, oligomers, and polymers containing ethylenically unsaturated bonds in their molecules are photopolymerized in the presence of a photopolymerization initiator. 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.

Various substances have been known as photopolymerization initiators used in the polymerization, and in practice, for example, benzoin compounds such as benzoin, benzoin methyl ether, and benzoin ethyl ether; benzyl, penzophenone, acetophenone, and Michler's ketone. Carbonyl compounds such as azobisisobutynitronyl, azo compounds such as azodibenzoyl: Sulfur compounds such as dibenzothiazolyl sulfide and tetrathiuram disulfide: carbon tetrachloride,
Halogen compounds such as tribromphenyl sulfone or 1
, 2-penzuanthraquinone, etc. are used.

Problems to be Solved by the Invention However, when an ethylenically unsaturated compound is polymerized using the photopolymerization initiator, radical polymerization is carried out, so the polymerization is easily inhibited by oxygen in the air. In order to improve surface hardening properties, problems arise, such as the need to increase the intensity of light irradiation, increase the concentration of the initiator, or lengthen the irradiation time.

Therefore, an object of the present invention is to provide a photopolymerization initiator that initiates photopolymerization upon exposure to light of a wide range of wavelengths, has excellent surface hardening properties, has a deep curing depth, and has good sensitivity.

Means for Solving the Problems> According to the present invention, the following general formula (I) ? In the formula, R and R2 each represent a hydrogen atom or a lower alkyl group, and R represents an alkyl group, an ester residue, an acyl group, or a benzoyl group), and a substituted aromatic amine represented by the following general formula: (II) (wherein R4 and R6 are
Tertiary alkyl group having 4 to 8 carbon atoms or 9 to 12 carbon atoms, respectively
represents a tertiary aralkyl group, R and R are each a hydrogen atom, a tertiary alkoxy group having 4 to 8 carbon atoms, or a tertiary alkyl group having 9 to 8 carbon atoms.
A photopolymerization initiator characterized by containing a penzophenone-containing polyhydric peroxyester represented by (12 tertiary aralkyloxy groups) is provided.

The present invention will be explained in more detail below.

The photopolymerization initiator of the present invention contains specific substituted aromatic amines and specific benzophenone group-containing polyhydric peroxyesters.

The substituted aromatic amines used in the present invention have the following general formula (I
), where R1 and R2 each represent a hydrogen atom or a lower alkyl group, and R3 represents an alkyl group, an ester residue, an acyl group, or a benzoyl group. Examples of the substituted aromatic amines represented by the general formula (I) include N,N-diethylaminobenzoic acid, N,N-dimethylaminobenzoic acid. Ethyl N,N-dimethylaminobenzoate, Ethyl N,N-diethylaminobenzoate, Isoamyl N,N-dimethylaminobenzoate, 1-2-ethylhexyl N,N-dimethylaminobenzoate. N,N-dimethylaminoacetophenone, N,N-diethylaminoacetophenone, N
, N-dimethylaminobenzophenone, N,N-diethylaminobenzophenone, N,N-dimethylpara-toluidine, N,N-diethylpara-toluidine, N,N-dimethylanobenzaldehyde. Examples include 4,4'-bis(dimethylamino)penzophenone, which can be used alone or as a mixture. It is also preferable to use substituted aromatic amines represented by the general formula (I) having absorption in the wavelength range of 300 to 700 nm. To prepare the substituted aromatic amines, for example, when preparing ethyl N,N-dimethylaminobenzoate, a method of reacting N,N-dimethylaminoamine, Q, aromatic acid chloride, and ethyl alcohol, etc. It can be obtained by

The benzophenone group-containing polyhydric peroxyesters used in the present invention can be represented by the following general formula (n), where R4 and R6 are each a tertiary alkyl group having 4 to 8 carbon atoms or a tertiary alkyl group having 9 to 8 carbon atoms. 12 represents a tertiary aralkyl group, R,
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. Production is difficult when R4 to R7 are a tertiary alkyl group or tertiary alkoxy group having 9 or more carbon atoms, a tertiary aralkyl group or tertiary aralkyloxy group having 13 or more carbon atoms. Examples of the penzophenone-containing polyhydric peroxy esters represented by the general formula (II) include 3.3', 4,4'-tetra(t-butylperoxycarbonyl)penzophenone. 3.3'4,4'-tetra(t-amylperoxycarbonyl)penzophenone, 3.3',4.4'-tetra(t-hexylperoxycarbonyl)benzophenone, 3.3',4.
4'-tetra(I-octylperoxycarbonyl)
Penzophenone, 3.3', 4.4'-tetra(cumylperoxycarbonyl)penzophenone, 3.3'
4.4'-tetra(p-isoprobylcumylperoxycarbonyl)penzophenone, 3.3'-(di-71butylperoxycarbonyl)-4.4'(dicarboxy)penzophenone or 3,3'(di-t-to) Examples include (xylperoxycarbonyl)-4,4'-dicarboxy)penzophenone, which can be used alone or as a mixture. To prepare the benzophenone-containing polyhydric peroxy esters, for example, when preparing 3,3',4,4'-tetra(t-butyloxycarbonyl)penzophenone, 3
．． It can be obtained by a method of reacting 3'4,4'-tetra(chloroformyl)penzophenone and t-butylhydroperoxide in an aqueous alkaline solution.

In the present invention, the blending ratio of the substituted aromatic amines and the benzophenone-containing polyhydric peroxyesters is preferably 0.1 by weight (substituted aromatic amines: benzophenone-containing polyhydric peroxyesters). ~9
9.9:99.9-0.1, particularly preferably ■-90:
The range is 99:10. If the blending ratio is outside the above range, excellent effects cannot be obtained, which is not preferable.

The photopolymerization initiator of the present invention can be prepared by mixing the substituted aromatic amine and the benzophenone group-containing polyhydric peroxyester. At this time, in addition to the above-mentioned essential ingredients, for example, pigments, fillers, dyes, sensitizers, and thermal polymerization inhibitors. Additives such as plasticizers, solvents, binders, etc. can 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 an ethylenically unsaturated bond in the molecule, such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, and croton. Examples thereof include acids, unsaturated carboxylic acids such as itaconic acid, and unsaturated carboxylic acid derivatives thereof.

Specifically, for example, monoesters such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, phenyl (meth)acrylate, benzyl (meth)acrylate; 2 Hydroxyalkyl esters such as monohydroxyethyl (meth)acrylate; ethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol Polyvalent esters such as tetra(meth)acrylate; (meth)acrylonitrile; (meth)acrylamide; N-
Substituted (meth)acrylamides; vinyl esters such as vinyl acetate, vinyl propionate, vinyl acrylate, and vinyl succinate; vinyl ethers, styrene, alkyl styrene, halogenated styrene, N-vinyl pyrrolidone, diacrylphthalate diallyl maleate, Vinyl compounds such as triallyl isocyanate and triallyl phosphate; fumarate group. malate group,
Examples include curable resins having allyl groups and (meth)acrylate groups, unsaturated polyesters, unsaturated acrylic resins, isocyanate-improved acrylate oligomers, polyester acrylic oligomers, and polyether acrylic oligomers, which may be used alone or as a mixture. Can be used.

To use the photopolymerization initiator of the present invention, it can be photopolymerized or photocured by mixing the photopolymerization initiator of the present invention with, for example, the ethylenically unsaturated compound and irradiating it with light.

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 parts by weight, based on 100 parts by weight of the ethylenically unsaturated compound. -20 parts by weight. If the amount used exceeds 40 parts by weight, the light transmittance may decrease, unreacted photopolymerization initiator may remain, and the physical properties of the obtained polymer may deteriorate, which is not preferable. Also 0.01
If the amount is less than 1 part by weight, the polymerization reaction will not be completed completely.
This is not preferred because unreacted ethylenically unsaturated compounds remain. Further, the light irradiated for photopolymerization or photocuring preferably has a wavelength of 350 to 700. As usable light sources, any light source that emits light having a wavelength within the above range can be used, and specifically, for example, sunlight, mercury lamps, hydrogen discharge tubes, xenon lamps, flash discharge tubes,
Examples include tungsten lamps, halogen lamps, metal halide lamps, and lasers.

Effects of the Invention> The photopolymerization initiator of the present invention is sensitive to light in the wavelength range of 350 to 700 nm, has excellent surface hardening properties and light transmittance, and has a deep curing depth. By combining with compounds, paints, adhesives, printing inks,
It can be used to harden printing boards, printed wiring boards, dental resin materials, etc., and can also be used to polymerize and harden thick films and molded bodies. In addition, the photopolymerization initiator of the present invention has improved sensitivity compared to conventional initiators for ultraviolet light, so it is superior in terms of workability and economy, and furthermore, visible light, which is harmless to the human body, can be used. 、It is also excellent in terms of safety.

<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.

A photopolymerization initiator v4 was prepared by mixing substituted aromatic amines and peroxy esters in the proportions shown in Table 1. Next, the obtained photopolymerization initiator was added and dissolved in a mixture of 100 parts of dipentaerythritol hexaacrylate and 100 parts 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 was approximately 20 μm, and then irradiated with a halogen lamp so that the average illuminance was approximately 20 mw/aJ. After 10 minutes of light irradiation, the pencil hardness of the coated film surface was measured according to JIS K5400 to evaluate surface hardening properties. The results are shown in Table 1.

Example 1 was carried out in the same manner as in Example 1, except that substituted aromatic amines or peroxyesters were used alone as shown in Table 1. The results are shown in Table 1.

The surface treatment results show that the photopolymerization initiator of the present invention improves the surface curability of the resulting cured product.

(Left below) Table 1 EB: Ethyl N,N-dimethylaminobenzoate AP: N
, N-dimethylaminoacetophenone ABP: N,N-
Dimethylaminobenzophenone PT: N,N-dimethylpara-toluidine BA: N,N-dimethylaminobenzaldehyde DBP: 4,4'-bis(dimethylamino)benzophenone TBB: 3.3',4.4'-tetra(t- butylperoxycarbonyl) penzophenone TAB: 3,3',4,4'-tetra(t-amylperoxycarbonyl)penzophenone THB: 3,3',4,4'-tetra(t-hexylperoxycarbonyl) Penzophenone TIB: 3.3',4,4'-tetra(p-isoprobylcumylperoxycarbonyl)penzophenone HCB:3,3'-(di-hexylperoxycarbonyl)-4. 4'-(Dicarboxy)penzophenone The photopolymerization initiator was prepared by mixing substituted aromatic amines and peroxy esters in the proportions shown in Table 2. Next, the obtained photopolymerization initiator was dissolved in an ethylenically unsaturated compound shown in Table 2 to obtain a photosensitive liquid. The obtained photosensitive liquid was filled into a polyethylene cylinder with an inner diameter of 10 mm and a depth of 10 mm, and a halogen lamp (I5V-150W) was inserted from the top of the cylinder.
) was irradiated with light to polymerize and cure. Also, Example 10
~12, In Examples 14 to 18, in order to clarify the effect of the radiation wavelength, a colored glass filter manufactured by Toshiba Corporation, product name rL-39J or Ha "Y-45" was installed on the top of the cylinder. Polymerization and curing were performed by irradiating light with the halogen lamp.

The radiation intensity at the top of the cylinder without a colored glass filter was measured with an Ebre thermopile and was 50 mW/a, but when a colored glass filter was installed, the radiation intensity was 1/2 It decreased to ~173 or less. The initiation efficiency of the photopolymerization initiator was determined by taking out the polymerized cured product from the cylinder, removing unreacted materials, and then measuring the curing depth of the photosensitive liquid using a micrometer. The results are shown in Table 2.

As is clear from the results 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 30 to 60 seconds using a halogen lamp. It was found that this method is possible, and that a cured product with a deep curing depth can be obtained due to its excellent light transmittance.

Also, from the results when installing glass filters of various colors,
Even though the radiation intensity was reduced to 172 to 1/3 or less, it was found that even long wavelength light can effectively polymerize and cure.

A photosensitive solution was prepared and tested in the same manner as in Examples 9 to 18, except that the photopolymerization initiator and ethylenically unsaturated compound shown in Table 3 were used.The results are shown below. Shown in 3.

From the results in Table 3, it is clear that substituted aromatic amines or benzophenone group-containing polyhydric peroxyesters alone do not cure sufficiently, and that a combination of common tertiary amines and penzophenone group-containing peroxyesters does not cure sufficiently. I found out that it doesn't.

(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 each represent a hydrogen atom or a lower alkyl group, and R_3 represents an alkyl group, ester residue,
acyl group or benzoyl group) and the following general formula (II) ▲There are numerical formulas, chemical formulas, tables, etc.▼...(II) (In the formula, R_4 and R_6 each have 4 carbon atoms -8 tertiary alkyl group or C9-12 tertiary aralkyl group, R_5 and R_7 are each a hydrogen atom, a C4-8 tertiary alkoxy group, or a C9-12 tertiary aralkyl group. A photopolymerization initiator characterized by containing a benzophenone-containing polyhydric peroxyester represented by (representing an oxy group).