JPH09176614A - Ultraviolet-absorbing agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an ultraviolet-absorbing agent excellent in ultraviolet- absorbing properties, aging stability, high-temp. stability, etc., by thermally reacting a specific benzil deriv., a specific benzaldehyde deriv., and ammonium acetate in glacial acetic acid. SOLUTION: A 2,4,5-triphenylimidazole deriv. compd. represented by formula III [e.g. 2-(2'-hydroxyphenyl)-4,5-diphenylimidazole] is obtd. by reacting a benzil deriv. represented by formula I, a benzaldehyde deriv. represented by formula II (in formulas I and II, R1 to R3 are each 1-8C alkyl, 1-4C alkoxy, hydroxyl, or halogen; m is 1, 2, or 3; and n and o are each 0, 1, 2, or 3), and ammonium acetate in glacial acetic acid for 2-4hr under reflux. The obtd. compd., if necessary after being compounded with an antioxidant, a light stabilizer, etc., is used as an ultraviolet absorbing agent, which is esp. suitable as an additive for plastics, coating materials, and cosmetics.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an ultraviolet absorber added to resins, particularly plastics and paints, cosmetics and the like.

[0002]

2. Description of the Related Art As is well known, resins, particularly plastics and paints, are destroyed and deteriorated remarkably rapidly by the action of light rays and the like, and discoloration such as yellowing, crack formation or embrittlement occurs. Light rays that destroy and deteriorate resin are in the wavelength range of 200 to 350n
Although it is an ultraviolet ray of m, the influence of the ultraviolet ray in the wavelength region of 300 to 320 nm is particularly great. An ultraviolet absorber is added to prevent the resin from being destroyed or deteriorated.

Conventionally, benzophenone-based derivatives, benzotriazole-based derivatives, salicylic acid-based derivatives, cinnamic acid-based derivatives, para-aminobenzoic acid-based derivatives, etc. have been used as ultraviolet absorbers for preventing the destruction and deterioration of resins. However, there are many cases where the absorbance in the wavelength range of 300 to 320 nm is insufficient, and even if the absorbance is sufficient, the absorption peak deviates from the wavelength range of 300 to 320 nm, which is not sufficient for cutting harmful ultraviolet rays. Met. Absorption peak is in wavelength region 30
There has been a demand for an ultraviolet absorber having a large absorbance in the vicinity of 0 to 320 nm and capable of sufficiently cutting harmful ultraviolet rays.

Further, plastics are often processed at a high temperature, and are usually processed at a temperature much higher than the disappearance temperature of the added ultraviolet absorber. For example, nylon and polycarbonate are processed at a high temperature. It is molded at 200 ℃ or higher. Due to the high temperature during processing of this plastic, the UV absorber often disappears, decomposes, and volatilizes,
An ultraviolet absorber excellent in high temperature stability has been desired.

[0005]

DISCLOSURE OF THE INVENTION The present invention is capable of sufficiently blocking harmful ultraviolet rays in the wavelength range of 300 to 320 nm, has excellent stability over time, and disappears or decomposes at high temperatures during processing of plastics. The present invention provides an ultraviolet absorber that is hard to volatilize and has excellent high temperature stability.

[0006]

As a result of intensive studies, the present inventors have found an ultraviolet absorber capable of achieving the above object, and completed the present invention.

That is, the present invention is an ultraviolet absorber comprising a 2,4,5-triphenylimidazole derivative compound represented by the following general formula (A).

[0008]

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(In the formula, R ₁ , R ₂ and R ₃ are each a carbon number of 1 to
8 represents an alkyl group, an alkoxy group having 1 to 4 carbon atoms, a hydroxy group or a halogen atom, and a plurality of R ₁ , R ₂ and R ₃ may be present, and a plurality of R ₁ , R ₂ and R ₃ are If present, each may be different or the same. m represents 1, 2 or 3. n and o are 0,
Represents 1, 2 or 3. )

Further, the present invention is an ultraviolet absorber comprising a 2,4,5-triphenylimidazole derivative compound represented by the following general formula (B).

[0011]

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(In the formula, R ₁ represents an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a hydroxy group or a halogen atom, and a plurality of R ₁ may be present; When R ₁ is present, each may be different,
It may be the same. m represents 1, 2 or 3. )

R ₁ , R ₂ and R ₃ represent an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a hydroxy group or a halogen atom. For example, as the alkyl group, a methyl group, Ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, sec-butyl group, t
ert-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group and the like, examples of the alkoxy group, methoxy group, ethoxy group, n-propyloxy group, iso-propyloxy group Group, n-butyloxy group, is
Examples thereof include o-butyloxy group, sec-butyloxy group and tert-butyloxy group, and examples of the halogen atom include fluorine atom, chlorine atom and bromine atom.

M of R ₁ is 1, 2 or 3, and n and o of R ₂ and R ₃ are 0, 1, 2 or 3, respectively. Multiple R ₁ , R ₂ and R ₃ may be present, and multiple R ₁ , R 2
_{When 2} and R ₃ are present, each may be different,
It may be the same.

The ultraviolet absorbent of the present invention is a plastic,
It is usually used by adding 0.01 wt% to 5 wt% to paints and cosmetics.

The plastics to which the ultraviolet absorber of the present invention is added include polymers of monoolefins or diolefins, copolymers of other vinyl monomers or diolefins, polystyrenes, dienes or acrylic acid derivatives and styrenes or α-methylstyrenes. From the above, halogen-containing polymers, polymers derived from unsaturated alcohols or amines or polymers derived from their acrylic derivatives or acetals.

Examples of the polymer derived from mono-olefin or di-olefin include low density or high density polyethylene, polypropylene, linear polybutene-1,
Examples include polyisoprene, polybutadiene, copolymers of mono- or di-olefins, and mixtures of the above polymers.

Other copolymers of vinyl monomers or diolefins include, for example, ethylene-alkyl acrylate-copolymers, ethylene-alkyl methacrylate-copolymers, ethylene-vinyl acetate-copolymers or ethylene-acrylic acid-copolymers.

As the copolymer of polystyrene, a diene or acrylic acid derivative and styrene or α-methylstyrene, for example, styrene-butadiene, styrene-acrylonitrile, styrene-ethyl methacrylate, styrene-butadiene-ethyl acrylate,
Examples thereof include styrene-acrylonitrile-methyl acrylate, acrylonitrile-butadiene-styrene and methylmethacrylate-butadiene-styrene.

As the halogen-containing polymer, for example,
Examples thereof include polyvinyl chloride, polyvinyl fluoride, polyvinylidene fluoride and copolymers thereof.

Examples of the polymer derived from α, β-unsaturated acid or its derivative include polyacrylate,
Examples thereof include polymethacrylate, polyacrylamide and polyacrylonitrile.

Examples of polymers derived from unsaturated alcohols and amines or acrylic derivatives or acetals thereof include polyvinyl alcohol,
Examples thereof include polyvinyl acetate, polyurethane, polyamide, polyurea, polyester, polycarbonate, polysulfone, polyether sulfone and polyether ketone.

The ultraviolet absorbent of the present invention has a high extinction temperature and excellent stability at high temperatures, and is suitable for heat resistant plastics that need to be processed at high temperatures.

Examples of paints to which the ultraviolet absorber of the present invention is added include oil paints, liquor paints, cellulose paints, synthetic resin paints and the like.

In the plastics and paints to which the ultraviolet absorber of the present invention is added, other additives such as, for example,
Antioxidants, light stabilizers, metal deactivators, antistatic agents, flameproofing agents, pigments, fillers and other UV absorbers may be added.

Examples of the above-mentioned other additive antioxidants include phenol-based antioxidants, sulfur-based antioxidants and phosphorus-based antioxidants.

As the phenolic antioxidant, for example, 2,6-di-tert-butyl-p-cresol, 2,6
-Di-tert-butyl-4-ethylphenol, stearyl-β- (3,5-di-tert-butyl-4-hydroxylphenyl) propionate, 1,1,3-tris (2-
Methyl-4-hydroxy-5-tert-butylphenyl)
Butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate, 1,3,5-tris [β- (3,
5-Di-tert-butyl-4-hydroxyphenyl) -propionyl-ethyl] isocyanurate, 1,3,5-tris (2,6-dimethyl-3-hydroxy-4-tert-
Examples include butyl-benzyl) isocyanurate, pentaerythritol-tetrakis- [β- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] and the like.

Examples of sulfur antioxidants include dilauryl thiodipropionate, dimyristyl thiodipropionate, distearyl thiodipropionate, pentaerythritol-tetrakis (β-lauryl thiopropionate), and pentalithuris. Thor-Tetrakis (β
-Hexyl thiopropionate) and the like.

Examples of phosphorus antioxidants include tris (nonylphenyl) phosphite, distearyl pentaerythritol diphosphite, tris (2,4-di-tert-butylphenyl) phosphite, tris (2 -Tert-butyl-4-methylphenyl)
Examples thereof include phosphite, bis (2,4-di-tert-butylphenyl) pentaerythritol phosphite, and tetrakis (2,4-di-tert-butylphenyl) -4,4'-bisphenylenediphosphite.

Further, other antioxidants include, for example, 2- (2'-hydroxyphenyl) benztriazole, 2-hydroxybenzophenone, aryl esters of hydroxybenzoic acid, α-cyanocinnamic acid derivatives, benzimidazole carboxylic acid. Examples thereof include acid anhydrides, nickel compounds, and aniline oxalic acid.

Further, other additives such as ultraviolet absorbers include, for example, 2- (2'-hydroxyphenyl) benztriazole, 2-hydroxybenzophenone, aryl esters from hydroxybenzoic acid, and α-cyanocinnamic acid derivatives. , Benzimidazolecarboxylic acid anhydrides, nickel compounds, dianiloxalic acid and the like.

Furthermore, when at least one light stabilizer of an amine compound is added together with the ultraviolet absorber of the present invention, the light stability is particularly good.

Examples of the light stabilizers for amine compounds include bis (2,2,6,6-tetramethylpiperidyl) quesevert, bis (1,2,2,2,6,6-pentamethylpiperidyl) quesevert, and -Hydroxylethyl-2,2,
Condensation product of 6,6-tetramethyl-4-hydroxypiperidine and succinic acid, N, N '-(2,2,6,6-
Tetramethylpiperidyl) hexamethylenediamine and 4
-Tert-octylamino-2,6-dichloro-1,3,5
Condensation product with -s-triazine, tris (2,2,
6,6-Tetremethylpiperidyl) nitrol triacetate, tetrakis (2,2,6,6-tetramethyl-4)
-Piperidyl) -1,2,3,4-butanetetracarboxylic acid, 1,1- (1,2-ethanediyl) -bis (3,3,
5,5-tetramethylpiperazinone), 4-amino-
An example is the condensation product of 2,2,6,6-tetramethylpiperidine and tetramethylolacetylene diurea.

The ultraviolet absorber of the present invention comprises a benzyl derivative, a benzaldehyde derivative and ammonium acetate,
Obtained by refluxing in glacial acetic acid for 2-4 hours. Further, instead of adding ammonium acetate, it is also possible to add ammonia water or ammonia to glacial acetic acid and add it secondarily. A general reaction formula is shown in Chemical formula 5.

[0035]

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The ultraviolet absorber of the present invention has an absorption peak in the wavelength region of 300 to 320 nm and a large absorbance.
It can block harmful ultraviolet rays sufficiently and has excellent high temperature stability, so it disappears at high temperatures during processing of plastics.
It is difficult to decompose and volatilize, and can be added to heat-resistant plastics.

[0037]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to Synthesis Examples and Examples of the ultraviolet absorbent of the present invention.
The present invention is not limited to these synthetic examples and examples. In addition, "parts" in the synthesis examples and practical examples are parts by weight,
"%" Represents% by weight.

Synthesis Example 1 21 parts of benzyl and salicylaldehyde were placed in a glass reactor.
After charging 12.2 parts, 77.1 parts of ammonium acetate and 600 parts of glacial acetic acid and reacting under reflux for 4 hours, the reaction solution was poured into ice water and made alkaline with ammonia water to precipitate crystals. Then, the crystals were collected by filtration, washed with water, and dried to obtain white crystals. The obtained crystal was analyzed by elemental analysis and ¹ H, ¹³ C—N
By MR, it was 2- (2′-hydroxyphenyl) -4,5-diphenylimidazole shown in Chemical formula 6. The results of elemental analysis are shown in Table 1. In addition, a spectrophotometer (Hitachi U
-3200), the maximum absorption wavelength λmax
= 316.8 nm, molar extinction coefficient ε = 2.25 x 10 ⁴ (methanol). Table 2 shows the results.

Synthesis Example 2 White crystals were obtained in the same manner as in Synthesis Example 1, except that 12.2 parts of 3-hydroxybenzaldehyde was used in place of 12.2 parts of salicylaldehyde. The obtained crystal was subjected to chemical analysis by elemental analysis and ¹ H, ¹³ C-NMR.
2- (3′-hydroxyphenyl) -4,5-diphenylimidazole shown in FIG. The results of elemental analysis are shown in Table 1. Also, λmax = 305.9 nm and ε = 2.39 × 10 ⁴ (methanol). Table 2 shows the results.

Synthesis Example 3 White crystals were obtained in the same manner as in Synthesis Example 1, except that 12.2 parts of 4-hydroxybenzaldehyde was used in place of 12.2 parts of salicylaldehyde. The obtained crystal was subjected to chemical analysis by elemental analysis and ¹ H, ¹³ C-NMR.
2- (4′-hydroxyphenyl) -4,5-diphenylimidazole shown in FIG. The results of elemental analysis are shown in Table 1. Also, λmax = 295.5 nm and ε = 2.74 × 10 ⁴ (methanol). Table 2 shows the results.

Synthesis Example 4 White crystals were obtained in the same manner as in Synthesis Example 1 except that 14.1 parts of 2-chlorobenzaldehyde was used instead of 12.2 parts of salicylaldehyde. The obtained crystal was 2- (2-chlorophenyl) -4,5-diphenylimidazole shown in Chemical formula 6 by elemental analysis and ¹ H, ¹³ C-NMR. The results of elemental analysis are shown in Table 1. Also, λmax = 291.7 nm, ε = 2.51 × 10 ⁴ (methanol)
Met. Table 2 shows the results.

Synthesis Example 5 White crystals were obtained in the same manner as in Synthesis Example 1, except that 16.2 parts of 4-tert-butylbenzaldehyde was used in place of 12.2 parts of salicylaldehyde. The obtained crystal was subjected to chemical analysis by elemental analysis and ¹ H, ¹³ C-NMR.
2- (4'-tert-butylphenyl) -4,5-diphenylimidazole shown in. Table 1 shows the results of elemental analysis
Shown in Also, λmax = 303.4 nm and ε = 3.28 × 10 ⁴ (methanol). Table 2 shows the results.

Synthesis Example 6 White crystals were obtained in the same manner as in Synthesis Example 1 except that 13.4 parts of 2,5-dimethylbenzaldehyde was used in place of 12.2 parts of salicylaldehyde. The obtained crystal was subjected to chemical analysis by elemental analysis and ¹ H, ¹³ C-NMR.
It was 2- (2,5-dimethylphenyl) -4,5-diphenylimidazole shown in. The results of elemental analysis are shown in Table 1. Further, λmax = 302.4 nm and ε = 3.43 × 10 ⁴ (methanol). Table 2 shows the results.

Synthesis Example 7 Except that 12.2 parts of 5-chlorosalicylaldehyde was used in place of 12.2 parts of salicylaldehyde in Synthesis Example 1,
White crystals were obtained in the same manner as in Synthesis Example 1. The obtained crystal was analyzed by elemental analysis and ¹ H- and ¹³ C-NMR to obtain 2- (5′-chloro-2′-hydroxyphenyl)-
It was 4,5-diphenylimidazole. The results of elemental analysis are shown in Table 1. Also, λmax = 310.8 nm, ε = 2.20
It was × 10 ⁴ (methanol). Table 2 shows the results.

Synthesis Example 8 In place of 12.2 parts of salicylaldehyde in Synthesis Example 1,
Synthesis Example 1 except that 13.6 parts of p-anisaldehyde was used
White crystals were obtained in the same manner as. The obtained crystal was analyzed by elemental analysis and ¹ H, ¹³ C-NMR to show the compound
It was (4′-methoxyphenyl) -4,5-diphenylimidazole. The results of elemental analysis are shown in Table 1. Also,
λmax = 305.3 nm and ε = 3.04 × 10 ⁴ (methanol). Table 2 shows the results.

[0046]

[Chemical 6]

Synthesis Example 9 White crystals were obtained in the same manner as in Synthesis Example 1 except that 27.9 parts of 4,4′-dichlorobenzyl was used instead of 21 parts of benzyl in Synthesis Example 1. The obtained crystals were analyzed by elemental analysis and
^It was 2- (2′-hydroxyphenyl) -4,5-di (4 ″ -chlorophenyl) imidazole shown in Chemical formula 7 by ¹ H, ¹³ C-NMR. The results of elemental analysis are shown in Table 1. Further, λmax = 314.4 nm and ε = 2.20 × 10 ⁴ (methanol). Table 2 shows the results.

Synthesis Example 10 Anisyl 27.0 was used in place of 21 parts of benzyl in Synthesis Example 1.
White crystals were obtained in the same manner as in Synthesis Example 1 except that parts were used. The obtained crystals were analyzed by elemental analysis and ¹ H, ¹³ C-NM.
By R, it was 2- (2′-hydroxyphenyl) -4,5-di (4 ″ -methoxyphenyl) imidazole shown in Chemical formula 7. The results of elemental analysis are shown in Table 1. Also, λ
The maximum was 306.8 nm and the molar absorbance was ε = 2.21 × 10 ⁴ (methanol). Table 2 shows the results.

Synthesis Example 11 In Synthesis Example 1, 4,4-di-t was substituted for 21 parts of benzyl.
Synthesis Example 1 except that 27.0 parts of ert-butylbenzyl was used
White crystals were obtained in the same manner as. The obtained crystal was analyzed by elemental analysis and ¹ H- and ¹³ C-NMR to obtain 2- (2 '
-Hydroxyphenyl) -4,5-di (4 ''-tert-butylphenyl) imidazole. The results of elemental analysis are shown in Table 1. Also, λmax = 305.2 nm, ε = 2.12 × 1
It was 0 ⁴ (methanol). Table 2 shows the results.

Synthesis Example 12 In Synthesis Example 1, 2-chloro- was used instead of 21 parts of benzyl.
Other than using 26.9 parts of 3 ', 4'-dimethoxybenzyl,
White crystals were obtained in the same manner as in Synthesis Example 1. The obtained crystal was analyzed by elemental analysis and ¹ H- and ¹³ C-NMR to show 2- (2′-hydroxyphenyl) -4- (3 ″, 4 ″)
It was -dimethoxyphenyl) -5- (2 '''-chlorophenyl) imidazole. The results of elemental analysis are shown in Table 1. Further, λmax = 311.9 nm and ε = 2.13 × 10 ⁴ (methanol). Table 2 shows the results.

Synthesis Example 13 White crystals were obtained in the same manner as in Synthesis Example 1, except that 24.2 parts of 4,4′-dihydroxybenzyl was used in place of 21 parts of benzyl in Synthesis Example 1. The obtained crystal was 2- (2′-hydroxyphenyl) -4,5-di (4 ″ -hydroxyphenyl) imidazole shown in Chemical formula 7 by elemental analysis and ¹ H, ¹³ C-NMR. Table 1 shows the results of elemental analysis
Shown in Also, λmax = 314.9 nm and ε = 2.09 × 10 ⁴ (methanol). Table 2 shows the results.

Synthesis Example 14 In Synthesis Example 1, anisyl 27.0 was used in place of 21 parts of benzyl.
A white crystal was obtained in the same manner as in Synthesis Example 1 except that 21.8 parts of 4-tert-octylbenzaldehyde was used in place of 12.2 parts of salicylaldehyde. The obtained crystal was analyzed by elemental analysis and ¹ H, ¹³ C-NMR to show
(4'-tert-octylphenyl) -4,5-di (4 ''-
Methoxyphenyl) imidazole. The results of elemental analysis are shown in Table 1. Also, λmax = 302.5 nm, ε = 3.35
It was × 10 ⁴ (methanol). Table 2 shows the results.

[0053]

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Synthesis Example 15 In Synthesis Example 1, 4 parts were used instead of 21 parts of salicylaldehyde.
White crystals were obtained in the same manner as in Synthesis Example 1 except that 18.5 parts of -bromobenzaldehyde was used. The obtained crystal was analyzed by elemental analysis and ¹ H, ¹³ C-NMR to show
It was (4′-bromophenyl) -4,5-diphenylimidazole. The results of elemental analysis are shown in Table 1. Also, λ
It was max = 295.2 nm and ε = 2.48 × 10 ⁴ (methanol). Table 2 shows the results.

Synthetic Example 16 In Synthetic Example 1, 4 parts were used instead of 21 parts of salicylaldehyde.
White crystals were obtained in the same manner as in Synthesis Example 1 except that 17.8 parts of -n-butoxybenzaldehyde was used. The obtained crystal was 2- (4′-n-butoxyphenyl) -4,5-diphenylimidazole shown in Chemical formula 8 by elemental analysis and ¹ H, ¹³ C-NMR. The results of elemental analysis are shown in Table 1. Also, λmax = 304.6 nm and ε = 3.08 × 10 ⁴ (methanol). Table 2 shows the results.

Synthesis Example 17 White crystals were obtained in the same manner as in Synthesis Example 1 except that 14.8 parts of 2,4,6-trimethylbenzaldehyde was used instead of 21 parts of salicylaldehyde. The obtained crystal was analyzed by elemental analysis and ¹ H- and ¹³ C-NMR to obtain 2 ′, 4 ′, 6′-trimethylphenyl) -4,5-
It was diphenylimidazole. The results of elemental analysis are shown in Table 1. Also, λmax = 306.2 nm, ε = 3.25 × 10
It was ⁴ (methanol). Table 2 shows the results.

Synthesis Example 18 White crystals were obtained in the same manner as in Synthesis Example 1 except that 14.2 parts of 2,4-difluorobenzaldehyde was used instead of 21 parts of salicylaldehyde. The obtained crystal was analyzed by elemental analysis and ¹ H, ¹³ C-NMR
2- (2 ', 4'-difluorophenyl) -4,5-
It was diphenylimidazole. The results of elemental analysis are shown in Table 1. Also, at λmax = 294.3 nm, ε = 2.63 × 10 ⁴
(Methanol) There was. Table 2 shows the results.

Synthesis Example 19 In Synthesis Example 1, 3,3′4, instead of 21 parts of benzyl,
White crystals were obtained in the same manner as in Synthesis Example 1 except that 39.0 parts of 4 ', 5,5'-hexamethoxybenzyl and 16.2 parts of 4-tert-butylbenzaldehyde were used in place of 12.2 parts of salicylaldehyde. The obtained crystals were analyzed by elemental analysis and ¹ H,
^{By 13} C-NMR, it was 2- (4′-tert-butylphenyl) -4,5-di (3 ′, 4 ′, 5′-trimethoxyphenyl) imidazole shown in Chemical formula 8. The results of elemental analysis are shown in Table 1. Also, λmax = 302.1 nm, ε = 3.10 × 10 ⁴
(Methanol). Table 2 shows the results.

[0059]

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[0060]

[Table 1]

[0061]

[Table 2]

Example 1 To polyvinyl chloride was added 0.05% of the ultraviolet absorber 2- (2'-hydroxyphenyl) -4,5-diphenylimidazole obtained in Synthesis Example 1 of the present invention, and the temperature was 140 ° C. A film having a thickness of 0.05 mm was prepared by mixing and using a roll. About the film and the blank to which the ultraviolet absorbent of the present invention was added, using a xenon fade meter (FAL-25AX-HCH-BEc manufactured by Suga Test Instruments Co., Ltd.),
The appearance change after irradiation with light rays for 400 hours and 800 hours was visually observed. Table 3 shows the results. As is clear from Table 3, the film added with the ultraviolet absorbent of the present invention has improved light resistance as compared with the blank.

[0063]

[Table 3]

Example 2 Polypropylene was added to each of the ultraviolet absorbers 2- (2'-hydroxyphenyl) -4,5 obtained in Synthesis Example 10 of the present invention.
-Di (4 ''-methoxyphenyl) imidazole 0.05%
(Sample 1), commercially available light stabilizer bis- (2,2,6,
6-Tetramethylpiperidyl) quesevert 0.05% (Sample 2), UV absorber 2- (2′-hydroxyphenyl) -4,5-di (4 ″-) obtained in Synthesis Example 10 of the present invention
Methoxyphenyl) imidazole 0.025% and a commercially available light stabilizer bis- (2,2,6,6-tetramethylpiperidyl) quesevert 0.025% (Sample 3) were added and the temperature was 180 ° C using an extruder. A sheet having a thickness of 4 mm was prepared. About the obtained sheet and blank, a xenon fade meter (Suga Test Instruments Co., Ltd., FAL-25A
X-HCH-B Ec) was irradiated with a light beam for a predetermined time, and then a bending test (according to JIS K6911-1962) was performed to measure the irradiation time when bending fracture was observed. Table 4 shows the results.

As is clear from Table 4, the sheet to which the ultraviolet absorbent according to the present invention is added has a life of 10 times as much as bending as compared with the blank. Further, by using the ultraviolet absorber of the present invention and the light stabilizer in combination, a synergistic effect on the life against bending was observed.

[0066]

[Table 4]

Example 3 For the transparent polyurethane paint, the ultraviolet absorber 2- (4'-methoxyphenyl) -obtained in Synthesis Example 8 of the present invention
After adding 0.2% of 4,5-diphenylimidazole, stirring, and then coating on a glass test plate with a bar coater,
It was solidified at a temperature of 25 ° C. Outdoor light (July-August) 400% for paints and blanks containing the ultraviolet absorber of the present invention
It was irradiated for a period of time, and the change in appearance was visually observed. Table 5 shows the results. The blank was clearly yellowed, but no change was observed in the appearance of the coating composition containing the ultraviolet absorber of the present invention.

[0068]

[Table 5]

Example 4 UV Absorber 2- (2′−) Obtained in Synthesis Example 1 of the Present Invention
Hydroxyphenyl) -4,5-diphenylimidazole, UV absorber 2- (2-chlorophenyl) -4,5-diphenylimidazole obtained in Synthesis Example 4, UV absorber 2- (4 obtained in Synthesis Example 14 '-Tert-octylphenyl) -4,5-di (4''-methoxyphenyl)
Imidazole and UV absorber 2 obtained in Synthesis Example 16
Thermogravimetric analysis of-(4'-n-butoxyphenyl) -4,5-diphenylimidazole and a commercially available ultraviolet absorber (commercially available products 1 to 5) shown in the following chemical formula 9 (in air, heating rate 10
(° C / min) was performed, and the temperature when the weight of the sample disappeared by 10% and 50% was measured to compare the thermal stability. Table 6 shows the results.

[0070]

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As is clear from Table 6, the ultraviolet absorber of the present invention has remarkably excellent thermal stability as compared with the commercially available ultraviolet absorber.

[0072]

[Table 6]

[0073]

The ultraviolet absorber of the present invention has an absorption peak in the wavelength region of 300 to 320 nm and a large molar absorptivity coefficient (ε) of 2 to 3 × 10 ⁴ (methanol), and addition of a small amount is sufficient. Excellent UV absorption capacity is obtained. Further, it has excellent stability over time for a long period of time, and does not have a decrease in ultraviolet absorption ability. Also, it disappears due to high temperature during plastic processing,
It is difficult to decompose and volatilize, has excellent high-temperature stability, and can be added to heat-resistant plastics.

Continuation of front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display area C08K 5/3445 KBJ C08K 5/3445 KBJ C08L 101/00 C08L 101/00

Claims (2)

[Claims] 1. A compound represented by the following general formula (A): 2,4,
An ultraviolet absorber comprising a 5-triphenylimidazole derivative compound. Embedded image (In the formula, R ₁ , R ₂ and R ₃ represent an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a hydroxy group or a halogen atom, and a plurality of R ₁ , R ₂ and R ₃ May be present, and when a plurality of R ₁ , R ₂ and R ₃ are present, each may be different or the same.
Represents 1, 2 or 3. n and o represent 0, 1, 2 or 3. ) 2. A compound represented by the following general formula (B): 2,4,5
-A UV absorber comprising a triphenylimidazole derivative compound. Embedded image (In the formula, R ₁ is an alkyl group having 1 to 8 carbon atoms and 1 carbon atom.
4 represents an alkoxy group, a hydroxy group or a halogen atom, and a plurality of R _1's may be present. When a plurality of R _1's are present, each may be different or the same. m represents 1, 2 or 3. )