JPS61258802A - Photopolymerizable composition - Google Patents

Abstract

PURPOSE:To provide the titled composition free from change in coloring and color tone with time, capable of giving products of good mechanical properties, e.g., printing material, dental filler, comprising a vinyl monomer and photopolymerization initiator consisting of a combination of mercaptocarboxylic acid and alpha-diketone. CONSTITUTION:The objective composition comprising (A) a vinyl monomer (e.g., ethylene glycol diacrylate, bisphenol A diglycidyl acrylate) and (B) normally 0.1-5wt%, based on said monomer, of, as a photopolymerization initiator, a combination of (i) mercaptocarboxylic acid [pref. a compound of formula I or II (R1 and R2 are each 1-5C alkylene or phenylene; R3 is NO2, OH, NH2 or halogen), e.g., o-mercaptobenzoic acid] and (ii) 0.1-20wt%, based on the component (i), of alpha-diketone (e.g., camphorquinone). EFFECT:Because of using such an initiator as to induce curing under the visible ray range, this composition will pose no health hazards; furthermore, the plant investment being inexpensive.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a photopolymerizable composition of a vinyl compound using mercaptocarboxylic acid and α-diketone as photoinitiators.

Photopolymerization can be used for printing plate materials, photosensitive agents for copying, printed wiring, I
It is used in a wide range of applications, including image formation for precision processing such as C, shadow masks, and paints, printing inks, and adhesives.

Photopolymerization is also used in the dental field; for example, photopolymerizable substances are used in the production of tooth filling materials (composite resins, etc.), tooth sealants and dental adhesives, caries prevention filling materials, dental crowns and dentures. Provided for manufacturing, etc.

[Conventional technology]

Conventionally, as the photopolymerizable compositions used as mentioned above, for example, Japanese Patent Publication No. 10986/1986 describes a photopolymerizable composition that can be cured by irradiation with visible light or ultraviolet light and has the following composition. things are listed. That is, this photopolymerizable composition uses a photosensitizer/reducing agent as a photoinitiator, and (
a) The following general formula % formula %), R3-R4 may be the same or different, are hydrogen or hydrocarbon groups, n is zero or 1, and the groups A are the same or or are distinctly hydrocarbon groups or substituted hydrocarbon groups, and both groups A are bonded together through a direct bond or a divalent hydrocarbon group, or even if both groups A are together may form a fused aromatic ring system, and the group A is an aromatic or substituted aromatic group when n is 1 and X is >CRIR2 and when n is zero. ) at least 1
and (b) the following general formula % formula % (wherein the units R may be the same or different and are hydrogen, a hydrocarbon group, a substituted hydrocarbon group, or two units R is a group forming a ring system with N, the three units R are not substituted hydrocarbon groups at the same time, and N is not directly bonded to an aromatic group). It consists of a photosensitive catalyst containing a reducing agent and a polymerizable ethylenically unsaturated substance. Among the above, particularly preferred photosensitizers include biacetyl, benzyl, benzophenone, and camphorquinone, and reducing agents include trimethylamine, tripropylamine, dimethylamine, )propylamine, N , N'-dimethylaniline, N-methyldiphenylamine, ethylenediamine, hexamethylenediamine, dimethylaminoethyl methacrylate and piperidine. Although materials using these photoinitiators are rapidly cured by light irradiation, the cured products are markedly colored (often yellow) and change significantly in color over time in sunlight and water, and have low physical strength and physical properties. It had the disadvantage that only one product could be obtained.

[Problem that the invention seeks to solve]

An object of the present invention is to provide a photopolymerizable composition that solves the problems of the prior art described above and provides a product that is free from coloration and color change over time and has excellent mechanical properties.

[Means for solving problems]

The photopolymerizable composition of the present invention is a photopolymerizable composition comprising a vinyl monomer and a photopolymerization initiator, and is characterized by using a combination of mercaptocarboxylic acid and α-diketone as the photopolymerization initiator.

The vinyl yarn thread forming the composition of the present invention may be a monofunctional vinyl compound or a polyfunctional vinyl compound. Examples of monofunctional vinyl compounds include styrene, acrylonitrile, vinyl acetate,
Examples include methyl acrylate and methacrylate, ethyl acrylate and methacrylate, butyl acrylate and methacrylate, hydroxyethyl acrylate and methacrylate, methoxyethyl acrylate and methacrylate, glycidyl acrylate and methacrylate, methacryloxyethyl trimellitic acid and its acid anhydride, and the like.

In addition, as an example of a polyfunctional vinyl compound, the following general formula % formula % (in the formula, R6 is a hydrogen atom or a methyl group, p is 1 to 20
is an integer. ) Ethylene glycol diacrylate and methacrylate, diethylene glycol diacrylate and methacrylate, triethylene glycol diacrylate and methacrylate, polyethylene glycol diacrylate and methacrylates, 1゜4-butanediol diacrylate and methacrylate, 1,3-butanediol diacrylate and methacrylate, 1,6-hexanediol diacrylate and methacrylate, glycerin diacrylate and methacrylate, and the following general formula (wherein R7 is a hydrogen atom or a methyl group, p is 1 to 20
is an integer. ), bisphenol A diglycidyl acrylate and methacrylates, urethane diacrylate and methacrylates, trimethylolpropane triacrylate and methacrylate, pentaerythritol tetraacrylate and methacrylate, bisphenol A diacrylate and methacrylate, and the like. These acrylates and methacrylates may be used alone or in combination of two or more.

The mercaptocarboxylic acid used as the photopolymerization initiator of the present invention preferably has the following general formula (where R8 and R
2 represents a direct bond, an alkylene group having 1 to 5 carbon atoms, or a phenylene group, and R2 represents a nitro group, a hydroxyl group, an amino group, or a halogen. ) is a compound represented by
Specific examples include o-, m- and p-mercaptobenzoic acid, o-, m- and p-mercaptophenylacetic acid,
o-, m- and p-mercaptophenylpropionic acid, o-, m- and p-mercaptophenylbutyric acid, mercaptobiphenylcarboxylic acid, o-, m- and p-mercaptomethylbenzoic acid, O-nitro-p-mercapto Benzoic acid, 0-hydroxy-p-mercaptobenzoic acid,
0-amino-p-mercaptobenzoic acid, 0-oo-p
-mercaptobenzoic acid and the like. Particularly preferred mercaptocarboxylic acids include O-mercaptobenzoic acid (thiosalicylic acid), m-mercaptobenzoic acid and p-mercaptobenzoic acid.
Examples include mercaptobenzoic acid.

α-diketones are not particularly limited and all can be used, but camphorquinone, benzyl, acetylbenzoyl, acenaphthenequinone α-naphthyl, dichlorobenzyl, biacetyl, β-naphthyl, benzoin, α-diketone, etc.
-naphthoin and β-naphthoin are preferred. Among them, camphorquinone is most preferred.

The above photopolymerization initiator is 1% relative to the above vinyl monomer.
Amounts from 0-5% to 30% by weight, preferably from 10-3% to 15% by weight, particularly preferably from 10-1 to 5% by weight
Add in the amount of The amount of α-diketone is 10-5% to 102% by weight based on mercaptocarboxylic acid.
, preferably in the range from 10-3% to 50% by weight, particularly preferably from to-'% to 20% by weight. These blending amounts are suitable for obtaining a composition that does not cause coloration or color change over time of the photopolymerized cured product and has high mechanical strength.

In the composition of the present invention, a filler is further added to the above-mentioned components as necessary. Such filler components include periodic law numbers r, n, m, and rv.

Examples include V group metals, transition metals, and their oxides, hydroxides, chlorides, sulfates, sulfites, carbonates, phosphates, silicates, and mixtures and composite salts thereof, among which silicon dioxide , quartz powder, aluminum oxide, barium sulfate, titanium oxide, talc, glass powder, glass beads, glass fiber, barium salt, glass filler containing lead salt, silica gel, colloidal silica, carbon fiber, zirconium oxide, tin oxide , other ceramic powders, etc. are preferred. The above-mentioned filler may be any of an untreated ring filler, a surface-treated filler using a silane coupling agent, and an organic composite filler composited with a polymer and pulverized.

The blending amount of the filler can be changed as appropriate depending on the purpose of use of the photopolymerized cured product, but for example, when used as a filling material for dental materials,
It is blended in a range of 1 to 103% by weight, preferably 10 to 9.5×10”% by weight, particularly preferably 20 to 9.0×102% by weight, and used as a paste composition.

Furthermore, the composition of the present invention may optionally contain a colorant, a polymerization inhibitor (e.g., hydroquinone, methoxybenzophenone, methylphenol, hydroquinone monomethyl ether, etc.), an oxidation stabilizer, and an ultraviolet absorber (e.g., penduphenone, etc.). , pigments (for example, iron oxide, titanium oxide, etc.), dyes, etc. can also be blended.

〔Effect of the invention〕

Since the photopolymerizable composition of the present invention uses a photopolymerization initiator that can be cured in the visible light range, it is not harmful to the human body, which is a drawback of conventional photopolymerization using ultraviolet light.
This method solves all problems such as poor curing performance (depth) and high equipment investment, and the cured product obtained by photocuring has excellent color stability that could not be obtained with conventional methods. and has good appearance performance and high mechanical properties.

〔Example〕

Next, the present invention will be explained in more detail with reference to examples, but the present invention is not limited to these examples.

Examples 1-3. A monomer mixture consisting of Comparative Examples 1 and 2 was poured into a Teflon cylinder (inner diameter 4 mm, height 20 mm) whose bottom surface was sealed until the upper liquid level coincided with the top surface of the Teflon cylinder. Next, the distance between the light irradiation surface of the 3M company's visible light irradiator (product name: 0PTILUX) and the above liquid level was 1 m1I+.
Visible light was irradiated for 0 seconds. Thereafter, the injection mixture was removed from the Teflon tube, the unpolymerized portion was removed, and the "thickness" of the resulting polymerized and cured product was measured.

Table 1 shows the type and amount of the photoinitiator and the results of the thickness measurement described above.

As is clear from Table 1, it can be seen that the composition according to the present invention has superior photocuring performance compared to the known composition of the comparative example. Moreover, the appearance of the photocurable polymer according to the present invention is as follows:
There was almost no coloration, and it was much cleaner than the comparative example.

A Teflon tube (inner diameter 4 ml, height 20
1) was packed until the upper paste surface was completely flush with the top surface of the Teflon tube. Next, 3M's visible light irradiator (product name:
Visible light was irradiated for 30 seconds with the paste surface placed such that the distance between the light irradiated surface of the 0PTILLIx and the paste surface was 1++ m. Thereafter, the injection paste was removed from the Teflon tube, the unpolymerized portion was removed, and the "thickness" of the resulting polymerized and cured product was measured.

Table 2 shows the type and amount of photoinitiator and the results of the above-mentioned "thickness" measurement.

As is clear from Table 2, even when a filler is added, the composition according to the present invention has superior photocuring performance compared to the known composition of the comparative example. In addition, the appearance of the photocurable polymer according to the present invention had almost no coloration and was significantly cleaner than that of the comparative example.

Comparative Example 5 After injecting the mixtures corresponding to Examples 1 and 4 into the Teflon cylinder, the top surface of the Teflon cylinder was covered with aluminum foil,
After making it impossible for visible light to reach the injection mixture, the mixture was placed so that the distance between the top surface of the injection mixture and the light irradiation surface was 1 mm, and visible light was irradiated for 3 minutes, but no polymerization occurred.

Comparative Example 6 After injecting the mixtures corresponding to Examples 1 and 4 into the Teflon cylinder, the top surface of the Teflon cylinder was covered with aluminum foil,
After making visible light unable to reach the injection mixture, 3
Although heated to 60° C. for minutes, no polymerization occurred.

Examples 7-9. A monomer filler mixture (paste) consisting of Comparative Examples 7 to 9 was operated in the same manner as in Example 4 and irradiated with visible light for 60 seconds,
The obtained photopolymerized cured product was cut into 4 x 6 mm cylindrical specimens, and their compressive strength, color change after a one-week exposure test to sunlight, and color tone change after a one-week immersion test in 60°C water were measured. was measured.

Table 3 shows the type and amount of the photoinitiator and the above measurement results.

As is clear from Table 3 below, it can be seen that the compositions according to the present invention have superior mechanical properties and extremely high color stability compared to the known compositions of comparative examples.

Claims (5)

[Claims] (1) A photopolymerizable composition comprising a vinyl monomer and a photopolymerization initiator, wherein the photopolymerization initiator is a combination of mercaptocarboxylic acid and α-diketone. (2) The photopolymerizable composition according to claim 1, further comprising a filler in addition to the vinyl monomer and the photopolymerization initiator. (3) Mercaptocarboxylic acid has the general formula ▲ Numerical formula, chemical formula, table, etc. ▼ (In the formula, R_1 and R_2 are direct bonds, carbon numbers 1 to 5
represents an alkylene group or a phenylene group, and R_3 represents a nitro group, a hydroxyl group, an amino group or a halogen. ) The photopolymerizable composition according to claim 1 or 2, which is a compound represented by: (4) The photopolymerizable composition according to claim 1 or 2, wherein the α-diketone is camphorquinone. (5) The photopolymerizable composition according to claim 1 or 2, wherein the mercaptocarboxylic acid is ortho-mercaptobenzoic acid (thiosalicylic acid), meta-mercaptobenzoic acid, or para-mercaptobenzoic acid.