JP2001348502A - 4,4'-di(benzoxazol-2-yl) stilbene derivative, fluorescent brightener easily soluble in resin and resin composition containing the fluorescent brightener - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluorescent brightener having excellent compatibility with thermoplastic resins, a new compound having a stilbene skeleton and useful as a component of a fluorescent brightener and a resin composition containing the fluorescent brightener in a state to suppress the re-aggregation tendency of the brightener. SOLUTION: The new 4,4'-di(benzoxazol-2-yl)stilbene derivative is expressed by general formula (1) ((n) is 0, 1 or 2; and R1 and R2 are each independently a 1-9C straight-chain or branched alkyl), the fluorescent brightener easily soluble in a resin contains the derivative and the resin composition contains the fluorescent brightener and a thermoplastic resin and suppresses the re-aggregation of the brightener. A laminate material is produced by using the resin composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a novel 4,4'-diene
More specifically, the present invention relates to a (benzoxazol-2-yl) stilbene derivative, and more specifically, a 6-membered ring of at least one benzoxazolyl group of 4,4′-bis (benzoxazol-2-yl) stilbene is an alkyl group. -With regard to substituted derivatives. The present invention also relates to a fluorescent whitening agent containing the stilbene derivative and a resin composition containing the fluorescent whitening agent.

[0002]

2. Description of the Related Art Many compounds having a stilbene type skeleton have an optical brightening effect of absorbing ultraviolet light having a wavelength of 350 to 400 nm and emitting strong blue-violet visible light "fluorescence", that is, a so-called fluorescent whitening effect. It is well known to have.

[0003] The benzoxazolyl group is unsubstituted 4,4 '
-Bis (benzoxazol-2-yl) stilbene, and 4,4'-bis (benzoxazol-2-yl)
A symmetric compound in which both benzoxazolyl groups of stilbene are substituted with the same substituent, an asymmetric compound in which both benzoxazolyl groups are substituted with different substituents, and only one benzoxazolyl group Asymmetric compounds in which is substituted are known.

[0004] For example, Japanese Patent Publication No.
No. 8307 discloses a symmetric 4,4'-bis (substituted benzoxazol-2-yl) stilbene compound in which both benzoxazolyl groups are substituted by the same substituent, for example, alkyl, alkoxy, allyl, halogen atom and the like. Shows an excellent fluorescent brightening effect on polyester-based and polyolefin-based polymers, and among them, 4,4'-bis (5-methylbenzoxazol-2-yl) stilbene is a resin which is directly kneaded. A symmetrical 4,4'-bis (substituted benzoxazole-2-yl) that significantly improves whiteness and condenses one mole of stilbene dicarboxylic acid with two moles of unsubstituted or substituted aminophenol.
Il) A method for producing a stilbene compound is disclosed.

Japanese Patent Publication No. 41-20225 discloses 2-
(4-formyl-phenyl) benzoxazoles and 2-
JP-B-44-6978 discloses a method for producing symmetric and asymmetric 4,4'-di (benzoxazol-2-yl) stilbene compounds by condensing with (4-methyl-phenyl) benzoxazoles. An asymmetric 4,4'-di (benzoxazole-) in which an unsubstituted or substituted aminophenol is condensed to a dicarboxylic acid in two steps.
A method for producing 2-yl) stilbene compounds is disclosed. Further, Japanese Patent Publication No. 44-9739 discloses an unsubstituted and substituted aminophenol with stilbene dicarboxylic acid.
Disclosed is a process for condensing more than one species to produce several mixtures of symmetric and asymmetric 4,4'-di (benzoxazol-2-yl) stilbene compounds. The compounds specifically described in each of the above documents are only compounds in which both or one of the benzoxazolyl groups is mono-substituted.

Japanese Patent Publication No. 42-19363, Japanese Patent Publication No. 43-4202, Japanese Patent Publication No. 44-23028, Japanese Patent Publication No. 47-36861, and Japanese Patent Application Laid-Open No. 48-6
No. 080 and the like, one of the above known compounds and 2
Optical brighteners comprising a mixture of more than one species and their application to various resins are disclosed.

Furthermore, various uses utilizing the fluorescent whitening action of the compound having a stilbene type skeleton, for example, application to printing inks, optical detection agents, polymer laminate materials for photographic and recording materials, etc. But, it is Tokubo 49-20
247, JP-A-2-254440, JP-T-2-502761, JP-A-11-286174, and the like.

[0008]

The above-mentioned compounds having a known stilbene-type skeleton have an excellent whitening effect as a fluorescent whitening agent and suitability for a wide range of uses. However, when they are applied as a fluorescent whitening agent for directly kneading into various thermoplastic resins, their compatibility with the base resin is incompatible because of their relatively long chemical structure and high melting point. This is sufficient and makes it difficult to perform a "kneading into resin" operation for preparing a uniform resin composition.

[0009] In the kneading work for polyester, polystyrene, polyamide, polycarbonate and the like, treatment at a high temperature of 250 to 350 ° C is required. As a result, due to the heat history represented by the product of the working temperature and the working time, not only deterioration of the resin composition is promoted,
The original whitening power of the fluorescent whitening agent is also impaired, and the whiteness of the resin composition is reduced.

Also, when used for a laminating material such as a polyolefin resin, the laminating operation is performed at 310 ° C.
Since it is required to perform the process at the above-mentioned high temperature, there is a risk of causing deterioration of the film itself, reduction of whiteness, contamination of equipment due to generation of sublimable gas, and deterioration of the working environment.

Further, even if a fluorescent whitening agent composed of a stilbene compound is uniformly kneaded into the resin by various means, they have a property of easily re-aggregating with time.
Re-agglomeration of the fluorescent whitening agent in the resin composition over time is likely to occur when applied to various thermoplastic resins represented by soft vinyl chloride, and oozes out onto the resin surface, resulting in turbidity, precipitation,
Generates spots and the like. In particular, in the case of laminating a polyolefin resin on a paper substrate such as a material for photography or information recording, very little bleeding or precipitation of the optical brightener must be avoided.

In order to solve these problems, for example, a method of kneading a fluorescent whitening agent into a thermoplastic resin in two steps by a master batch method, a method of using ultra-fine particles of a fluorescent whitening agent, and the like. However, none of these proposals provide a fundamental solution.

An object of the present invention is to provide a novel compound having a stilbene-type skeleton having a lower melting point while maintaining a fluorescent whitening effect equivalent to that of a known compound. Another object of the present invention is to provide a resin-soluble fluorescent whitening agent which has excellent compatibility with a thermoplastic resin and can be easily kneaded into the resin. Another object of the present invention is to provide a resin composition in which re-aggregation of a fluorescent whitening agent is unlikely to occur, particularly a resin composition suitable as a laminate material for a substrate.

[0014]

Means for Solving the Problems The present inventors have conducted intensive studies to achieve the above object, and as a result, have found that at least one benzoxazolyl group of 4,4'-bis (benzoxazol-2-yl) stilbene is required. A novel 4,4'-di (benzoxazol-2-yl) stilbene derivative having a 6-membered ring di-substituted with an alkyl group has an ultraviolet maximum absorption wavelength (λmax) of about 380 nm and a low melting point. Have been found to be excellent in compatibility with various thermoplastic resins, and have completed the present invention.

The present invention provides a compound represented by the following general formula (1):

Embedded image Wherein n is 0, 1 or 2, and each of R ¹ and R ² independently represents a linear or branched chain alkyl group having 1 to 9 carbon atoms. It is a 4,4'-di (benzoxazol-2-yl) stilbene derivative.

Another object of the present invention is to provide a resin containing at least one member selected from the group consisting of 4,4'-di (benzoxazol-2-yl) stilbene derivatives represented by the above general formula (1). It is a soluble fluorescent whitening agent.

Another aspect of the present invention is a resin composition comprising the above resin-soluble fluorescent whitening agent and a thermoplastic resin, which may further contain a white pigment. Yet another invention is
A laminate material comprising the above resin composition.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The 4,4'-di (benzoxazol-2-yl) stilbene derivative of the present invention is a compound represented by the general formula (1), And 7-position is R ^1, that is, a linear or branched chain alkyl group having 1 to 9 carbon atoms,
A substituted symmetric or asymmetric compound.

In the general formula (1), R ¹ represents, for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-
Butyl group, pentyl group, isopentyl group, neopentyl group, tert-pentyl group, hexyl group, isohexyl group,
Heptyl group, tert-heptyl group, octyl group, 2-ethylhexyl group, tert-octyl group (1,3-tetramethylbutyl group), nonyl group, tert-nonyl group (1,4-tetramethylheptyl group), etc. It is a linear or branched chain alkyl group having 1 to 9 carbon atoms. Each of R ¹ may be the same or different, but is usually the same.

The other benzoxazolyl group has the general formula
(1) n in is 0, that is unsubstituted, n is mono 1 i.e. R ² - or substituted or n is 2 namely R ² of di - substituted. If n ≠ 0, R ^2
1 include the same alkyl group and they may be the same or different and the R ^1, also in the case of n = 2, R ²
May be the same or different. The substitution position of the benzoxazolyl group by R ² is not particularly limited, but n
= 1, usually 5′-position, n = 2, usually
5'-position and 7'-position.

Specific examples of the 4,4'-di (benzoxazol-2-yl) stilbene derivative of the present invention are shown in (a-1) below.
To (a-11).

[0022]

Embedded image

The 4,4'-di (benzoxazol-2-yl) stilbene derivative represented by the general formula (1) can be produced by various known synthesis methods. For example, a symmetrical 4,4'-bis (dialkylbenzoxazol-2-yl) stilbene compound is a dialkylaminophenol di-substituted with a predetermined alkyl group per mole of 4,4'-stilbene dicarboxylic acid. In the method of condensing 2 moles (see Japanese Patent Publication No. 42-8307), an asymmetric 4,4'-di (benzoxazol-2-yl) stilbene compound is unsubstituted or mono- or di-substituted with a predetermined alkyl group. Method for condensing equimolar between substituted 2- (4-formyl-phenyl) benzoxazole and di- or mono-substituted or unsubstituted 2- (4-methylphenyl) benzoxazole with a predetermined alkyl group (See Japanese Patent Publication No. 42-20225) 4,4 '
A method for synthesizing an asymmetric 4,4'-di (benzoxazol-2-yl) stilbene compound in two steps starting from stilbene dicarboxylic acid (JP-B-44-6987, JP-B-44-23028, Tokiko 47-36
861) and the like. Further, a method comprising reacting a mixture containing at least one derivative of the present invention with 2,4'-stilbene dicarboxylic acid by two or more aminophenols having different substituents is disclosed in JP-B-44-9739. Can be synthesized according to

The 4,4'-di (benzoxazol-2-yl) stilbene derivative represented by the above general formula (1) has a relatively low melting point and an ultraviolet maximum absorption measured in a dimethylformamide solution. The wavelength (λmax) is approximately 380 nm, and has an excellent fluorescent whitening effect. Further, it has good compatibility with various thermoplastic resins.

The resin-soluble fluorescent whitening agent of the present invention comprises 4,4'-di (benzoxazole-) represented by the above general formula (1).
2-yl) at least one selected from the group consisting of stilbene derivatives. That is, one compound represented by the general formula (1) alone, a mixture of two or more compounds,
And mixtures thereof with known optical brighteners.

[0026] As a fluorescent whitening agent component, wherein R ¹ in the general formula (1) is the same kind of alkyl group having a branch of 3-9 carbon atoms compounds are preferred, more preferably -C R ¹ are both The compound is a (CH ₃ ) ₂ CH ₂ CH ₃ group and n ≠ 0. Among them, compound (a-1) exemplified above
Is particularly preferable because it has an extremely low melting point of 180 to 181 ° C. and has excellent compatibility with various thermoplastic resins.

Compounds having a known stilbene type skeleton, such as unsubstituted 4,4'-bis (benzoxazol-2-yl), may be used as a fluorescent whitening agent component other than the compound represented by the general formula (1). ) Symmetric 4,4'-bis in which stilbene and benzoxazolyl groups are monosubstituted with alkyl groups
(5-alkylbenzoxazol-2-yl) stilbene, wherein both benzoxazolyl groups are different alkyl mono-
Unsymmetrical 4,4'-di (benzoxazol-2-yl) stilbene derivatives which are substituted or only one of them is mono-substituted.

The resin-soluble fluorescent whitening agent contains a total of 20% by weight or more of the derivative represented by the general formula (1) based on the total weight of the fluorescent whitening agent. When the content of these derivatives is too small, the effect of improving the compatibility with the fluorescent whitening agent is reduced, the time for kneading into the thermoplastic resin is lengthened, and the effect of preventing reaggregation is also reduced.

Since the resin-soluble fluorescent whitening agent of the present invention has excellent compatibility with various thermoplastic resins, it facilitates the operation of "kneading into resin", and a resin composition obtained by uniformly kneading it is used. The working time for preparation is greatly reduced.

The resin composition of the present invention comprises a resin-soluble fluorescent whitening agent having the above characteristics and a thermoplastic resin,
Further, a white pigment is optionally contained. As the thermoplastic resin component, soft and hard polyvinyl chlorides, polyolefins such as polyethylene, polypropylene, poly 1-butene and copolymers thereof, such as polystyrene, polyester, polyacrylonitrile, polyamide, polycarbonate, polyurethane, and poly (meth) acryl Acid esters, polyvinyl acetal, and the like, and mixtures thereof.

The amount of the fluorescent whitening agent in the resin composition varies depending on the type of the thermoplastic resin, the purpose of use, and the like, but is usually 0.01 to 0.3% by weight based on the weight of the resin component. This range may be increased or decreased as needed.

As a white pigment for imparting whiteness to the resin composition, inorganic pigments such as titanium dioxide, titanium phosphate, zinc oxide, basic lead carbonate, antimony oxide, zinc sulfide, and composite salts thereof may be used. The use of titanium dioxide or titanium dioxide based pigments is usually common. The content of the white pigment is usually in the range of 0.3 to 30% by weight based on the total weight of the resin composition. The resin composition further contains, if desired, a general additive to the resin composition, for example, an antioxidant, a heat stabilizer, an antistatic agent, a coupling agent,
A coating aid and the like can be included.

In the production of the resin composition, a resin-soluble fluorescent whitening agent is melt-kneaded with a thermoplastic resin, a white pigment and various additives using a Burberry mixer, various kneaders, a two- or three-roll kneader, or the like. By doing so, the fluorescent whitening agent can be uniformly kneaded in a component such as a thermoplastic resin in a very short time.

Since the resin composition of the present invention has high whiteness, it can be used for spinning, woven fabric, nonwoven fabric, long and short fibers for synthetic paper, etc., single fibers such as tex yarn, various packaging films, sheets, boards, And can be used as a raw material for producing molded articles having a desired shape, etc., and impart high whiteness to those products.

The resin composition using soft vinyl chloride or polyolefin, especially polyethylene, as the thermoplastic resin has substantially no reagglomeration and exudation of the optical brightener contained therein, or has no reagglomeration and exudation. Since the start time is greatly delayed as compared with known optical brighteners, it can be suitably used as a laminate material for various substrates requiring recording of images and information. Substrates to which the laminate material is applied include paper substrates such as photographic printing paper, information recording paper and printing paper, film substrates such as information recording films and various packaging films, and plastic substrates such as plastic molded products such as PET bottles. And glass moldings.

[0036]

The present invention will be described in more detail with reference to Examples and Comparative Examples. In the following examples, “parts” and “%” are based on weight.

Example 1 Synthesis of 4,4'-di (benzoxazol-2-yl) stilbene derivative Synthesis Example 1 Compound (a-1)

Embedded image

2-amino- in 250 parts of chlorobenzene
2,4.9 parts (0.1 mol) of 4,6-di-tert-pentylphenol were added, and 4,4'-stilbenedicarboxylic acid dichloride 1 was added while stirring and heating to 120 to 130 ° C.
5.3 parts (0.05 mol) were added and reacted for 4 hours.
The reaction product was collected by filtration, 5 parts of zinc chloride was added, and the mixture was heated to 170 to 190 ° C. in a nitrogen stream to effect cyclocondensation in a molten state for about 1 hour. After completion of the reaction, the product was crushed, washed with 10% hydrochloric acid and then with hot water, dried, and further purified by recrystallization from a dimethylformamide solution, melting point (mp) 18
Compound (a-1) 4,4'-bis having 0 to 181 ° C
29.5 parts of pale yellow-white crystals of (5,7-di-tert-pentyl-benzoxazol-2-yl) stilbene were obtained. The maximum absorption wavelength (λmax) of the obtained crystals in a dimethylformamide solution was 380.0 nm.

Synthesis Example 2 Compound (a-2)

Embedded image

2- (4-formyl-phenyl) -5-te
rt-octyl-benzoxazole 16.8 parts (0.0
5 mol), 2- (4-methyl-phenyl) -5,7-di-
21.7 parts (0.05 mol) of tert-octyl-benzoxazole and 5 parts of zinc chloride were mixed well, and reacted at 230 to 260 ° C. for 3 hours under a nitrogen stream. After allowing to cool, the product was finely ground, 150 parts of 2% hydrochloric acid was added, and the mixture was heated to 60 ° C. while stirring, and then the solid content was collected by filtration and washed well with water. Further, 150 parts of methanol was added and the mixture was heated and washed, and the solid content collected by filtration was purified by recrystallization from a dimethylformamide solution, and the melting point (mp) was 286-2.
Compound (a-2) having a temperature of 89 ° C. 4- (5,7-di-te)
rt-octyl-benzoxazol-2-yl)-
30.0 parts of pale yellowish white crystals of 4 '-(5'-tert-octyl-benzoxazol-2'-yl) stilbene were obtained. The maximum absorption wavelength (λmax) of the obtained crystal in a dimethylformamide solution was 380.8 nm.

Synthesis Example 3 Compound (a-3)

Embedded image

12.5 parts (0.05 mol) of 2-amino-4,6-di-tert-pentylphenol, 4,4'-
13.4 parts (0.05 mol) of stilbene dicarboxylic acid, 8 parts of ethylene glycol and 3 parts of boric acid were stirred well, charged into a reaction vessel, gradually heated, and heated and maintained at 170 to 180 ° C. for about 5 hours. . When almost no distillate water was observed, the contents were allowed to cool and the contents were taken out, crushed and washed with hot water. Next, a 3% sodium hydroxide solution was added thereto, followed by heating, and the solid content was collected by filtration and washed with water to obtain a monocarboxylic acid. 19.2 parts (0.04 mol) of the obtained monocarboxylic acid, 8.8 parts (0.04 mol) of 2-amino-4,6-di-tert-butylphenol, 2.5 parts of boric acid and ethylene glycol Five parts were mixed well, put again in a reaction vessel, and heated to 230 to 250 ° C. while flowing nitrogen gas to complete the reaction. After completion of the reaction, the reaction product was allowed to cool and the product was taken out of the reaction vessel, washed with a 3% aqueous sodium hydroxide solution and then with water, dried, and further purified by recrystallization from a dimethylformamide solution.
Compound (a-3) having a temperature of from 38 to 242 ° C, 4- (5,7-
23.3 parts of pale yellow-white crystals of di-tert-pentyl-benzoxazol-2-yl) -4 '-(5', 7'-di-tert-butyl-benzoxazol-2'-yl) stilbene were obtained. Was. The ultraviolet maximum absorption wavelength (λma) of the obtained compound (a-3) in a dimethylformamide solution
x) was 380.5 nm.

SYNTHESIS EXAMPLE 4 According to any of Synthesis Examples 1 to 3, the starting compounds were used to synthesize the exemplified compounds (a-4) to (a-11). Compound (a-4) 4- (5,7-di-tert-pentyl-benzoxazol-2-yl) -4 '-(5'-tert-butyl-benzoxazol-2'-yl) stilbene mp = 265 ２７273 ° C. λmax = 379.6 nm Compound (a-5) 4,4′-bis (5,7-di-tert-butyl-benzoxazol-2-yl) stilbene mp = 264-265 ° C. λmax = 379.8 nm Compound (a-6) 4- (5,7-di-tert-octyl-benzoxazol-2-yl) -4 '-(5', 7'-dimethyl-benzoxazol-2'-yl) stilbene mp = 273-278 ° C. λmax = 380.2 nm Compound (a-7) 4- (5,7-di-tert-butylbenzoxazol-2-yl) -4 ′-(5′-ethylbenzoxazol-2′-yl ) Stilbene mp = 280-282 ° Cmax = 379.0 nm Compound (a-8) 4- (5,7-di-tert-pentyl-benzoxazol-2-yl) -4 '-(5'-tert-octyl-
Benzoxazol-2'-yl) stilbene compound (a-9) 4- (5,7-di-tert-butyl-benzoxazol-2-yl) -4 '-(5', 7'-dimethylbenzoxazole- 2'-yl) stilbene compound (a-10) 4,4'-bis (5,7-dimethyl-benzoxazol-2-yl) stilbene compound (a-11) 4- (5,7-di-tert- Pentyl-benzoxazol-2-yl) -4 '-(5'-methyl-benzoxazol-2'-yl) stilbene

Synthesis Example 5 The following known compounds (b-1) to (b-6) were synthesized according to any of the above Synthesis Examples 1 to 3, except that the starting materials were changed. Compound (b-1) 4,4′-bis (5-tert-butyl-benzoxazol-2-yl) stilbene mp = 300-304 ° C. λmax = 378.4 nm Compound (b-2) 4,4′-bis (5-isopropyl-benzoxazol-2-yl) stilbene mp = 310 ° C. λmax = 378.0 nm Compound (b-3) 4,4′-bis (5-ethyl-benzoxazole-2-
Yl) stilbene compound (b-4) 4,4'-bis (5-methyl-benzoxazole-2-
Yl) stilbene mp = 327 ° C. λmax = 376.5 nm compound (b-5) 4- (5-methyl-benzoxazol-2-yl)-
4 '-(benzoxazol-2'-yl) stilbene mp = 337-338 ° C. λmax = 374.4 nm Compound (b-6) 4,4′-bis (benzoxazol-2-yl) stilbene mp = 350 ° C. λmax = 373.5 nm

The chemical formulas of the compounds (b-1) to (b-6) are shown below.

Embedded image

Example 2 Resin-Easily Soluble Fluorescent Whitening Agent Compounds (a-1) to (a-7) synthesized alone and one or more of compounds (a-1) to (a-11) and a compound ( b
-1) to (b-6), a resin-soluble fluorescent whitening agent (La-1) to (La-10), and a compound (b-1) to (b-6) comprising a mixture with at least one of them. Optical brightener (Lb-) consisting solely of the above and a mixture of two or more thereof.
1) to (Lb-5) were prepared at two levels of an average particle diameter of 10 μm and 100 μm, respectively. The melting points (mp) of these optical brighteners and the maximum ultraviolet absorption wavelength (λmax) measured in a dimethylformamide solution are shown in Tables 1 and 2.
Shown in

[0047]

[Table 1]

[0048]

[Table 2]

As shown in Tables 1 and 2, when compared to known optical brighteners, the optical brighteners of the present invention show approximately the same ultraviolet maximum absorption wavelength and have a lower melting point.

Example 3 Resin Composition 3-A Soft Vinyl Chloride Resin Composition The optical brightener (La-1) of the present invention prepared in Example 2 was used.
(La-3) and (La-8), and each of the comparative optical brighteners (Lb-1) and (Lb-5),
Vinyl chloride resin (trade name: SMILIT SX-11F,
Sumitomo Chemical), 50% dioctyl phthalate based on vinyl chloride resin, 4.0% stabilizer (trade name: TVS #)
8501, manufactured by Nitto Kasei Co., Ltd.) and 2.0% of titanium dioxide.
The mixture was kneaded at 70 ° C. using a two-roll kneader, and a fluorescent whitening agent was uniformly kneaded to prepare a soft vinyl chloride resin composition. Subsequently, the obtained resin composition was put into a mold and compression-molded at 100 atm to prepare a sample for evaluating re-agglomeration. All of the obtained evaluation samples showed extremely high whiteness.

The blending amounts of the fluorescent whitening agent are two levels of the fluorescent whitening agent (La-1) of 0.1% (light color density) and 0.3% (dark color density) based on the weight of the vinyl chloride resin. The reference concentration was used, and for the other optical brighteners, the compound (a-1)
Was added as the light and dark color densities, respectively. The uniform mixing of the fluorescent whitening agent was determined by visually observing the sample collected during kneading under a UV light source (black light) and through a loupe. Table 3 shows the amount of the fluorescent whitening agent and the time (minutes) required for uniform mixing.

In addition, each of the reaggregation evaluation samples was
℃, 60% RH in a dark room maintained at a constant temperature and humidity,
Re-aggregation of the optical brightener was observed under irradiation of an ultraviolet lamp. Table 3 shows the elapsed days until the occurrence of reaggregation.

[0053]

[Table 3]

As shown in Table 3, in the case of the soft vinyl chloride resin composition containing the fluorescent whitening agent of the present invention, the time required for uniform mixing of the fluorescent whitening agent was reduced by the addition of a known fluorescent whitening agent. It is greatly shortened compared to the case where In addition, the re-aggregation start time of the optical brightener in the evaluation sample is significantly prolonged as compared with the known optical brighteners. I can't. Accordingly, the soft vinyl chloride resin composition containing the optical brightener of the present invention can be used as a laminate material for a paper substrate for photography or information recording.

3-B Polyethylene Resin Composition The resin-soluble fluorescent whitening agents (La-1) and (La-
4), (La-9) and (La-10) and each of the comparative optical brighteners (Lb-2) and (Lb-4) were added to polyethylene resin (trade name: Hi-Zex 5000S) by polyethylene. It was blended with 0.5% of titanium dioxide on a resin basis and melt-kneaded at a kneading temperature of 170 to 180 ° C. using a two-roll kneader to prepare a polyethylene resin composition. The obtained resin composition was put into a mold, and compression-molded at 100 atm to prepare a sample for leaching evaluation. All of the obtained evaluation samples showed extremely high whiteness.

The compounding amount of the fluorescent whitening agent was 0.020% of the fluorescent whitening agent (La-1) as a reference concentration based on the weight of the polyethylene resin, and for the other fluorescent whitening agents, the compound (a-1) was used. ) Was added. Table 4 shows the amount of the fluorescent whitening agent and the time (minutes) required for uniform kneading determined in the same manner as in the above-mentioned 3-A. In addition, the prepared evaluation sample was left in a dark room maintained at a constant temperature and humidity of 25 ° C. and 60% RH, lightly stroked with a non-fluorescent white cloth, and observed under irradiation of an ultraviolet lamp. The presence or absence of fluorescence transfer was examined by using the following method. The time point at which the transfer of the fluorescence was observed was defined as the time when the bleeding of the fluorescent whitening agent occurred, and the number of days until the bleeding occurred is shown in Table 4.

[0057]

[Table 4]

As shown in Table 4, the time required for the resin-soluble fluorescent whitening agent of the present invention to be uniformly kneaded into the polyethylene resin was greatly reduced as compared with the known fluorescent whitening agents. , The leaching time from the sample is greatly extended,
Virtually not allowed. Therefore, the polyethylene resin composition containing the optical brightener of the present invention can be suitably used as a laminating material for a paper substrate for photography or information recording.

3-C Polyester Resin Composition The optical brighteners (La-1) and (L) prepared in Example 2 were used.
a-5) to (La-7), and for comparison (Lb-3)
And (Lb-2), a polyester resin (trade name: Teijin Tetron TR-8550, manufactured by Teijin),
Blended in a mixture consisting of 1.0% titanium dioxide and 0.5% zinc stearate based on polyester resin,
A kneading is performed at a kneading temperature of 260 to 270 ° C. using a single screw extruder, followed by injection molding, and a whiteness evaluation sample (1 ° C.) of a polyester resin composition in which a fluorescent whitening agent is uniformly dispersed.
z, 50 t).

The amount of the fluorescent whitening agent is based on two levels of the fluorescent whitening agent (La-1) of 0.01% (light color density) and 0.03% (dark color density) based on the weight of the polyester resin. Concentration, and for the other optical brighteners, the compound (a-
The molar equivalents of 1) were added as light and dark color densities, respectively. Table 5 shows the blending amount of the optical brightener and the time (minutes) required for uniform kneading determined in the same manner as in 3-A.
Shown in

The whiteness of the sheet containing the fluorescent whitening agent (La-1) was evaluated as 100, and the whiteness was evaluated separately.
Each sample was visually observed under a xenon standard light source, and the whiteness was measured. Table 5 shows the measurement results of the whiteness.

[0062]

[Table 5]

As shown in Table 5, in the polyester resin composition containing the fluorescent whitening agent of the present invention, the time required for the uniform mixing of the fluorescent whitening agent was longer than that of the known whitening agent. Is significantly reduced as compared to Also, high whiteness is maintained when a fluorescent whitening agent having an average particle size of 100 μm is used. Therefore, when the resin-soluble fluorescent whitening agent of the present invention is blended, the step of pulverizing the fluorescent whitening agent can be omitted.

[0064]

The present invention provides a novel 4,4'-di (benzoxazol-2-yl) stilbene derivative. They exhibit an ultraviolet maximum absorption wavelength (λmax) of about 380 nm and have an excellent fluorescent whitening action. In addition, a fluorescent whitening agent consisting of a single compound of these compounds and a mixture containing at least one of these compounds has a lower melting point than known fluorescent whitening agents, and has various melting points with various thermoplastic resins. Since it has excellent compatibility and is easily soluble in resin, it can be uniformly kneaded into various resins in an extremely short time.

Furthermore, the resin composition of the present invention has high whiteness and prevents re-aggregation and bleeding of the optical brightener incorporated therein. In particular, a resin composition in which the thermoplastic resin component is soft polyvinyl chloride or polyolefin is suitable as a laminate material for various substrates, especially paper substrates for recording photographic images and information.

The present invention relates to a novel 4,4'-di (benzoxazol-2-yl) stilbene derivative, a resin-soluble fluorescent whitening agent containing at least one of them, and a resin containing the fluorescent whitening agent. The present invention provides a composition and a laminate material comprising the resin composition, and its industrial significance is extremely large.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08K 3/00 C08K 3/00 5/353 5/353 C08L 101/00 C08L 101/00 F term (reference) 4C056 AA01 AB01 AC02 AD03 AE02 CA03 CA09 CC01 CD02 4F100 AK01B AK03B AK15B AT00A BA02 CA13B CA13K DG10A GB41 GB71 JB16B JL10 4H056 DA02 DC01 DD23 DE02 FA02 4J002 BB031 BB121 DE03 BG171 BG131 BB171 BC031BD03 BB171 BC031

Claims (9)

[Claims] 1. The following general formula (1): Wherein n is 0, 1 or 2, and each of R ¹ and R ² independently represents a linear or branched chain alkyl group having 1 to 9 carbon atoms. 4,4'-di (benzoxazol-2-yl) stilbene derivatives. 2. A resin containing at least one selected from the group consisting of 4,4′-di (benzoxazol-2-yl) stilbene derivatives represented by the general formula (1) according to claim 1. Soluble optical brightener. (3) 4,4'-di (benzoxazole-2-
Yl) stilbene derivatives wherein R ¹ in the general formula (1) are both-
C (CH ₃₎ resins easily soluble fluorescent whitening agent of claim 2 wherein at least one compound is a ₂ CH ₂ CH _3. 4. Formula (1) based on the total weight of the optical brightener
The resin-soluble fluorescent whitening agent according to claim 2 or 3, which contains a 4,4'-di (benzoxazol-2-yl) stilbene derivative represented by the following formula in a total amount of 20% by weight or more. 5. A resin composition comprising the resin-soluble fluorescent whitening agent according to claim 2 and a thermoplastic resin, which may further contain a white pigment. 6. The thermoplastic resin is selected from the group consisting of polyvinyl chloride, polyolefin, polystyrene, polyester, polyacrylonitrile, polyamide, polyurethane, poly (meth) acrylate, polyvinyl acetal, and mixtures thereof. The resin composition as described in the above. 7. A laminate material of the resin composition according to claim 5 on a heterogeneous substrate. 8. The laminate material according to claim 7, wherein the thermoplastic resin component of the resin composition is soft polyvinyl chloride or polyolefin. 9. The laminate material according to claim 7, wherein the substrate is a paper substrate as a photographic and / or information recording material.