JPH0578409A - Photopolymerizable composition - Google Patents

Abstract

(57) [Summary] [Structure] 100 parts by weight of a monomer having at least one radically polymerizable unsaturated group in the molecule, and having a maximum light absorption peak in the range of 400 to 800 nm in a state of being dissolved in the above monomer and visible Pigment that changes color with light 0.0001 to 0.5
A photopolymerizable composition containing parts by weight and a visible light polymerization initiator in an amount of 0.01 to 3 parts by weight. [Effect] It shows sufficient light transmittance for photocuring, and the degree of photocuring can be identified by the change in color.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to photopolymerizable compositions. More specifically, it relates to a photochromic photopolymerizable composition in which the degree of photocuring can be known by a change in color.

[0002]

2. Description of the Related Art In recent years, photocurable materials have come to be used in various fields. The photocurable composition is superior to the conventional room temperature curable material in terms of operability, while, of course, the photocurable material usually cures only a portion where light is sufficiently transmitted. Therefore, in order to know whether or not the curing has progressed sufficiently, it was therefore necessary to try, for example, directly scraping the back surface of the light irradiation surface.

On the other hand, by adding a photochromic photoinitiator to the photocurable material, it will be possible to know the degree of photocuring by the degree of progress of color change. In addition, in the case of an ultraviolet curable composition, most dyes change their colors quickly due to ultraviolet rays,
The degree of photo-curing can be known by incorporating an ordinary dye. However, the inclusion of the dye causes a new defect that the curability of the ultraviolet curable composition is lowered. This also applies to the visible light curable composition. That is, since the visible light curable composition usually contains a camphorquinone or an allyl ketone-containing photoinitiator as a photoinitiator, the inclusion of a photochromic compound usually increases the degree of coloring and lowers the light transmittance. As a result, the curability by light is deteriorated.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a photopolymerizable composition. Another object of the present invention is to provide a photopolymerizable composition containing a visible light initiator and a dye having specific visible light characteristics, but not low in photocurability like the above conventional compositions. is there.

Further objects and advantages of the present invention will be apparent from the following description.

[0006]

According to the present invention, the above objects and advantages of the present invention are (A) 100 parts by weight of a monomer having at least one radically polymerizable unsaturated group in the molecule, (B) the above 400-80 when dissolved in monomer
A dye having a maximum light absorption peak in the range of 0 nm and yet changing color with visible light 0.0001 to 0.5 parts by weight, and (C) a visible light polymerization initiator 0.0.
It is achieved by a photopolymerizable composition characterized by containing 1 to 3 parts by weight.

The photopolymerizable composition of the present invention is as described above.
Monomer (A), dye (B) and photopolymerization initiator (C)
Contains.

The monomer (A) is a compound having at least one radically polymerizable unsaturated group in the molecule.

Examples of the monomer (A) include alkyl methacrylate such as methyl methacrylate, ethyl methacrylate and n-butyl methacrylate; alkyl acrylate such as methyl acrylate, ethyl acrylate, iso-propyl acrylate and butyl acrylate; aromatic such as styrene. Vinyl compounds; and ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, bisphenol A
Preferred examples thereof include di (meth) acrylates such as di (meth) acrylate; and polyfunctional (meth) acrylic acid ester monomers such as trimethylolpropane tri (meth) acrylate.

The monomer (A) may be used alone or in the form of 2
More than one species can be used together.

The dye (B) has a maximum light absorption peak in the range of 400 to 800 nm in a state of being dissolved in the above-mentioned monomer and is discolored by visible light.

In particular, such a dye has a light absorption maximum peak in the range of 500 to 800 nm and a light absorption minimum value in the range of 400 to 500 in a state of being dissolved in the above-mentioned monomer, and has the light absorption maximum. It is preferable that the ratio of the absorbance at the peak to the absorbance at the light absorption minimum value is at least 5.

As such a dye, for example, Michler's ketone or crystal violet is advantageously used.

The dye (B) is the above-mentioned monomer (A) 100.
It is used in an amount of 0.0001 to 0.5 part by weight, preferably 0.0002 to 0.4 part by weight.

The initiator (C) is a compound which is cleaved by visible light to generate a radical.

As such an initiator, 400 to 500 n
An initiator having a maximum light absorption peak in the range of m is preferably used.

Examples of such an initiator include camphorquinone, benzyl, 3-ketocoumarin, 2-methylthioxanthone, 2,4-diethylthioxanthone, 2,4,
Suitable examples include 6-trimethylbenzoyl, diphenylphosphine oxide, and other commercially available photoinitiators.

In addition to the above-mentioned components, the composition of the present invention contains, if necessary, 85% by weight of an inorganic powder for the purpose of improving the hardness of the cured product and glass fiber for the purpose of improving the strength. It can be contained in the following proportions.

The composition of the present invention is prepared by adding the above-mentioned components in any order, either intermittently or simultaneously, and thoroughly stirring and mixing.

The present invention will be described in detail below with reference to examples. The invention is in no way limited by these examples.

[0021]

【Example】

Reference Example 1 50 mg of Michler's ketone and 5 mg of crystal violet were each dissolved in 100 ml of methyl methacrylate, and the absorption spectrum of each obtained solution was measured by an ultraviolet-visible spectrophotometer. Absorption maximum and 400-500
The absorption minimum in nm was as shown in Table 1.

[0022]

[Table 1]

Comparative Example 1 3 g of urethane dimethacrylate (addition product of 1 molecule of 2,2,4-trimethylhexamethylene diisocyanate and 2 molecules of hydroxyethyl methacrylate), 1 g of triethylene glycol dimethacrylate, glass powder (manufactured by Shot Japan Co.) Dental glass GM8235) 9 g, allyl ketone-containing photoinitiator (Merck Darocur 16
64) was mixed with a spatula on a glass dough plate, and the resulting paste was degassed under vacuum. When the photocurability was examined with a dental photopolymerizer (Dentacolor XS manufactured by Cru Tour Co., Ltd., West Germany), the results shown in Table 2 are shown.

Example 1 2 mg of crystal violet was added to 20 g of the paste of Comparative Example 1 before defoaming, and the mixture was degassed under vacuum. The photocurability was as shown in Table 2.

Comparative Example 2 3 g of the same urethane-based dimethacrylate as in Comparative Example 1, 1 g of triethylene glycol dimethacrylate, 9 g of glass powder and 2.6 g of crosslinkable polymethylmethacrylate,
47 mg of camphorquinone was mixed with a spatula on a glass plate, and the obtained pace was degassed under vacuum. The curability was as shown in Table 2.

Example 2 0.5 mg of crystal violet was added to 20 g of the paste before defoaming of Comparative Example 2 and mixed, and then defoamed under vacuum.
The curability was as shown in Table 2.

Example 3 10 mg of Michler's ketone was added to 2 g of the paste before defoaming of Comparative Example 2, mixed and defoamed. The curability was as shown in Table 2.

[0028]

[Table 2]

Claims (4)

[Claims] 1. A monomer having at least one radically polymerizable unsaturated group (A) in the molecule.
100 parts by weight, (B) 400 to 800 n in a state of being dissolved in the above monomer
A dye having a maximum light absorption peak between m and 0.0001 to 0.5 parts by weight that changes color with visible light, and (C) a visible light polymerization initiator.
The photopolymerizable composition is characterized by containing 0.01 to 3 parts by weight. 2. The visible light polymerization initiator is 400 to 500 nm.
The photopolymerizable composition according to claim 1, which has a maximum light absorption peak in the range. 3. The dye has a maximum light absorption peak in the range of 500 to 800 nm and a minimum light absorption value in the range of 400 to 500 nm in a state of being dissolved in the monomer of the component (A).
The photopolymerizable composition according to claim 1, wherein the ratio of the absorbance at the maximum light absorption peak to the absorbance at the minimum light absorption value is at least 5. 4. The photopolymerizable composition according to claim 1, wherein the dye is Michler's ketone or crystal violet.