JP2008195674A - Rare earth metal complex graft copolymerizable with EVA resin and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluorescent rare earth metal complex easily available at a low cost while keeping the binding property to synthetic resins. <P>SOLUTION: The fluorescent rare earth metal complex graft-copolymerizable with synthetic resins contains a ligand comprising an aromatic carboxylic acid having two adjacent alkoxy groups as substituents. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention provides a stable composition obtained by graft copolymerization with a matrix resin when a rare earth metal complex is used as a composition with a synthetic resin for a solar cell sealing material, a light emitting resin panel, a fluorescent film forming material, or the like. The present invention relates to a novel rare earth metal complex capable of forming selenium and a method for producing the same.

  Rare earth metals are usually most stable in oxidation state 3, but Eu, Yb, Sm can also form complexes of oxidation state 2, and Ce forms a tetravalent compound. The bond is highly ionic and tends to have a higher coordination number, so after reacting with the anionic ligand necessary to neutralize the positive charge (usually 3+), further neutral organic A rare earth metal complex can be obtained by reacting a ligand.

And so far, many rare earth metal complexes having, for example, C ₅ H ₅ , C ₅ (CH ₃ ) ₅ and C ₈ CH ₈ as neutral organic ligands are known, and some of them are compounds Are used as synthetic intermediates, polymerization catalysts, and the like (see Non-Patent Document 1). Many rare earth metal complexes having cyclopentadienyl, pentamethylcyclodienyl, cyclooctatetraene, bipyridyl, and phenanthroline are also known.

  As a result of recent progress in research on the development of conjugates of organic compounds and metal ions, NMR chiral shift reagents containing rare earth metal complexes with 6- to 8-dentate amino acid derivatives as active ingredients An optical resolution reagent (see Patent Document 1), a complex of an aromatic carbonyl compound such as naphthaldehyde, acetonaphthone or 10-methylacridone and a metal ion such as magnesium ion, lutetium ion, ytterbium ion or scandium ion. A light emitting material (see Patent Document 2) is proposed.

  On the other hand, when the phosphor powder is mixed with a resin material to form a light-emitting panel, or when the phosphor is mixed with a matrix resin and a solvent to form a phosphor film forming composition, the resin material or the matrix resin is ethylene.・ Use a vinyl acetate copolymer (hereinafter referred to as EVA) (see Patent Documents 3 and 4), and uniformly absorb fluorescent rare earth metal complex powder that absorbs light of 450 nm or less and emits light in the visible region in the EVA resin. It is known to disperse and use with a solar cell sealing material (see Patent Documents 5 and 6).

  By the way, when phosphor powder is dispersed in an EVA resin matrix in this way, it has been a uniform composition by physical dispersion until now, but after this is dispersed in the resin by melting, resin molecules and If it can be chemically bonded, a more uniform and stable composition can be obtained. Therefore, the present inventors have previously made a fluorescent rare earth metal complex that can be graft copolymerized with a resin molecule by reacting with various crosslinking agents. The present inventors proposed a fluorescent rare earth metal complex having a benzoic acid derivative having an alkenyloxy group as a substituent as a ligand and a resin composition comprising the same and a synthetic resin (see Patent Document 7).

JP 2002-20358 A (Claims and others) JP 2003-183639 A (Claims and others) JP 2004-249644 A (claims and others) JP-A-8-102257 (Claims and others) JP 2006-298974 A (Claims and others) JP 2006-303033 A (Claims and others) Japanese Patent Application No. 2006-57024 (Claims and others) "Fourth Edition Experimental Chemistry Lecture 18 Organometallic Complex", published by Maruzen, edited by The Chemical Society of Japan, p. 36-48

Fluorescent rare earth metal complexes previously proposed as rare earth metal complex powders that can be dispersed uniformly in a synthetic resin and chemically bonded to the synthetic resin and stabilized when reacted with various crosslinking agents are Because it uses an aromatic carboxylic acid having a chain alkenyloxy group as a ligand, it has low heat and light stability, is difficult to manufacture, is subject to high costs, and is used industrially. This is not always appropriate.
The present invention has been made for the purpose of providing a fluorescent rare earth metal complex which is free from the above-mentioned disadvantages of the fluorescent rare earth metal complex and which can be easily and inexpensively obtained while maintaining the copolymerizability to the synthetic resin. It is a thing.

  The present inventors have conducted various studies on fluorescent rare earth metal complexes that can be uniformly dispersed and chemically bonded with a synthetic resin when reacted with various crosslinking agents. Focusing on the alkoxyl group that is stable and inexpensive to manufacture, even if a compound having an alkoxyl group instead of an alkenyloxy group is used as a ligand of conventional fluorescent rare earth metal complexes, it retains the binding property to the synthetic resin As a result, it was found that a fluorescent rare earth metal complex having good stability to light and heat and having high storage stability was obtained, and the present invention was made based on this finding.

  That is, the present invention relates to a fluorescent rare earth metal complex that can be graft-copolymerized with a synthetic resin, which has an aromatic carboxylic acid having two adjacent alkoxyloxy groups as substituents as a ligand, and a method for producing the same Is to provide.

  Although the rare earth metal is used as the central metal in the metal complex of the present invention, there is no particular limitation on the rare earth metal, that is, a metal belonging to the rare earth, that is, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, Any of terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, yttrium and scandium can be used.

  In addition, the aromatic carboxylic acid derivative coordinated to the central metal is a ligand for neutralizing the positive charge (3+) of the central metal, and therefore three molecules are coordinated per atom of the rare earth metal. There is a need. As a source of the ligand, an aromatic carboxylic acid or a salt thereof, for example, an alkali metal salt such as sodium salt or potassium salt is used. This aromatic carboxylic acid needs to have two adjacent alkoxy groups as substituents. And the alkoxyl group of this substituent has a preferable thing which has 1-10 carbon atoms, especially 3-8.

Particularly preferred aromatic carboxylic acids are those of the general formula (RO) n-Ar-COOH (I)
(In the formula, Ar is an aromatic ring group, R is an alkyl group containing 1 to 10 carbon atoms, and n is an integer of 2 to 4)
And two of the above R must be connected adjacently. Ar in the formula represents an aromatic ring, but this is not limited to a carbocyclic ring and may be a heterocyclic group having aromaticity.

Examples of the aromatic carboxylic acid represented by the above general formula (I) include 3,4-diethoxybenzoic acid, 3,4-dipropoxybenzoic acid, 3,4-dibutoxybenzoic acid, and 3,4-dihexyloxybenzoic acid. Acid, 1,3,4-tripropoxybenzoic acid, 1-methoxy-3,4-butoxybenzoic acid, 3,4-dibutoxy-1-naphthoic acid, 5,6-dibutoxy-1-naphthoic acid, 3,4 -Dibutoxy-2-pyridine acid and the like.
Most preferred among these is 3,4-dibutoxybenzoic acid.

  These substituted aromatic carboxylic acids, for example, react with an alkyl halide in the presence of an alkali in a substituted aromatic carboxylic acid ethyl ester having a corresponding polyhydroxyl group in the presence of an alkali to introduce an ester bond. Obtained by hydrolysis. The desired substituted aromatic carboxylic acid is easily recovered from the above reaction mixture according to a conventional method.

  The neutral organic ligand introduced as a ligand in addition to the aromatic carboxylic acid in the complex of the present invention is an organic amine and an organic phosphorus compound. As the organic amine, tertiary amines such as phenanthroline, bipyridine, quinoline and pyridine are preferable, and as the organic phosphorus compound, triphenyl phosphate, trithiophenyl phosphate, tri (4-butoxyphenyl) phosphate. Etc. are preferable.

The fluorescent rare earth metal complex that can be graft copolymerized with the synthetic resin of the present invention can be produced, for example, as follows.
That is, the rare earth metal oxide powder is dissolved in an organic solvent to which an inorganic acid is added. At this time, if desired, the reaction can be promoted by heating and stirring. If a uniform solution is formed, a predetermined aromatic carboxylic acid and an organic amine are introduced into this solution, and a white solid is precipitated by adjusting the pH with a base. After sufficiently depositing a white solid, this is filtered off, and the organic solvent is washed with water and dried under reduced pressure. In this way, the desired complex is obtained in a yield of 50% or more based on the rare earth metal oxide used. The fact that this product is the target complex can be identified by, for example, elemental analysis values and infrared absorption spectra.

Examples of rare earth metal oxides used in the above reaction include Sc ₂ O ₃ , Y ₂ O ₃ , La ₂ O ₃ , Eu ₂ O ₃ , Sm ₂ O ₃ , and Tb ₄ O ₇ . These rare earth metal oxides are used in the form of powder having a particle size of 100 μm or less, preferably 10 μm or less, dispersed in an organic solvent.

  The organic solvent can be arbitrarily selected from those conventionally used in the production of organic rare earth metal complexes. Examples of such organic solvents include methanol, ethanol, propanol, acetonitrile, dimethylformamide (DMF), diethylacetamide, tetrahydrofuran (THF), acetone, chloroform, methylene chloride, ethyl acetate, butyl acetate, dimethyl sulfoxide, and diethyl sulfoxide. There is.

  In the method of the present invention, the rare earth metal oxide powder is added to the organic solvent and uniformly dispersed by stirring. The ratio of the organic solvent used in this case is selected in the range of 1:30 to 1: 300, preferably 1:50 to 1: 200, by mass ratio with respect to the rare earth metal oxide.

  In addition, as the inorganic acid used at this time, strong acids such as hydrochloric acid, chloric acid, sulfuric acid, and nitric acid are used. The amount of the inorganic acid used should be at least stoichiometric, preferably slightly excessive, relative to the rare earth metal powder.

  Moreover, there is no restriction | limiting in particular as heating temperature, Usually, 40 degreeC or more, Preferably it selects in the range of 60-100 degreeC. This heat treatment is continued until the mixed solution becomes a substantially transparent solution. This treatment time depends on the kind of rare earth metal, the kind of inorganic acid, the concentration of inorganic acid, etc., but is usually in the range of 10 minutes to 5 hours.

  The thus obtained fluorescent rare earth metal complex of the present invention is mixed with a synthetic resin (for example, EVA), and easily combined with the synthetic resin by adding a crosslinking agent and heating to form a chemically uniform composition. Form.

  The mixing ratio of the synthetic resin and the complex at this time is usually selected in an amount not exceeding 10% based on the weight of the synthetic resin, preferably 0.01 to 8%, particularly 0.05 to 1%. If the amount of the complex is less than 0.01%, the desired fluorescence intensity cannot be obtained, and if it exceeds 10%, the fluorescence intensity is not improved even if the amount of the complex used is increased, which is economically undesirable.

  The composition composed of the synthetic resin and the complex can be heated by adding an organic peroxide as a crosslinking agent, thereby forming a crosslinked structure and improving the mechanical strength.

As the cross-linking agent, an organic oxide that efficiently cross-links a polyethylene-based synthetic resin is mainly used. Any one that generates radicals at 100 ° C. or higher can be used, but in consideration of the stability at the time of blending, those having a decomposition temperature of 10 hours half-life of 70 ° C. or higher are preferable.
Examples of such compounds include peroxyketal compounds such as 1,1-di (t-hexylperoxy) cyclohexane, 1,1-di (butylperoxy) -2-methylcyclohexane, dialkyl peroxide. Dicumyl peroxide in the system, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, di-t-hexyl peroxide, t-hexylperoxybenzoate in the peroxyester system, 2, Examples include 5-dimethyl-2,5-di (benzoxyperoxy) hexane and t-butylperoxybenzoate.
The blending amount of the organic peroxide is sufficient up to 5% by mass with respect to the synthetic resin.

In the composition, a crosslinking aid can be added to improve the degree of crosslinking and improve durability.
As this crosslinking aid, trifunctional crosslinking aids such as triallyl isocyanurate and triallyl isocyanate, and monofunctional crosslinking aids such as NK ester are used. The blending amount of the crosslinking aid is sufficient up to 10% by mass with respect to the synthetic resin.

In addition, a stabilizer such as hydroxyquinone, hydroxyquinone monomethyl ether, P-benzoquinone or methylhydroquinone can be added to the composition in order to improve the stability.
The blending amount of the stabilizer is sufficient up to 5% by mass with respect to EVA.

  Furthermore, an ultraviolet absorber, an antiaging agent, a discoloration preventing agent and the like can be added to the composition.

  Examples of ultraviolet absorbers include benzophenone series such as 2-hydroxy-4-n-octoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone, and 2- (2′-hydroxy5-methylphenyl) benzo A hindered amine type such as benzotriazole type such as triazole, phenyl salicylate, or pt-butylphenyl salicylate is used.

  Antiaging agents include amines, phenols, bisphenyls, hindered amines such as di-t-butyl-p-cresol, bis (2,2,6,6-tetramethyl-4-piperazyl) sebacate, etc. Is used.

  The fluorescent rare earth metal complex of the present invention can be produced at low cost and has the advantage of excellent storage stability because it is stable to light and heat, and this is mixed with a synthetic resin such as EVA. The solar cell encapsulant prepared as described above exhibits good uniform dispersibility and has an effect that it can be used in a stable state over a long period of time.

  Next, the best mode for carrying out the present invention will be described by way of examples, but the present invention is not limited thereto.

Reference Example To a suspension of 11 g (59 mmol) of ethyl 3,4-dihydrobenzoate, 9 g (65 mmol) of potassium carbonate and 120 ml of DMF, 130 ml of 1.1 M 1-bromobutane DMF solution was slowly added dropwise and reacted at 90 ° C. for 18 hours. I let you. After cooling the reaction solution to room temperature, the product is extracted with ether, dried, the solvent is removed, and the resulting brown white solid is recrystallized with ethanol to obtain ethyl 3,4-butoxybenzoate. It was.
Next, a solution of ethyl 3,4-butoxybenzoate (15 g, 51 mmol) and sodium hydroxide (4.0 g) in ethanol (200 ml) was refluxed for 12 hours. After cooling the reaction solution to room temperature, ether (200 ml) and 1N hydrochloric acid were added. After the layers were separated and dried, the solvent was removed. The yellowish white solid obtained was recrystallized from methanol to obtain 9.1 g of 3,4-dibutoxybenzoic acid. The yield at this time was 68%. The ¹ H, ¹³ C-NMR, and infrared absorption spectra of this product were as follows.
3,4-Dibutoxybenzoic acid; ¹ H-NMR (δ, ppm): 0.99 (—CH ₃ , t, J = 7.5 Hz, 6H), 1.52 (—CH ₂ —, m, 4H), _{1.84 (-CH 2 -, m,} 4H), 4.07 (-OCH 2 -, q, J = 7.6Hz, 4H), 6.90 (-C 6 H 3 -, d, J = 8 .6 Hz, 1 H), 7.59 (-C ₆ H _3- , d, J = 2.0 Hz, ₁ H), 7.72 (-C ₆ H _3- , dd, J ₁ = 9.2 Hz, J ₂ = 2.0 Hz, 1 H);); ¹³ C-NMR (δ, ppm): 14.2 (—CH ₃ ), 19.6 (—CH ₂ —), 31.5 (—CH ₂ —), 31 _{.6 (-CH 2 -), 69.1} (-OCH 2 -), 69.4 (-OCH 2 -), 112.3,114.9,121.7,124.9,148.9,154 4,172.1 (-CO-) IR (KBr): 2957,2871,1670,1597,1521,1443,1277,1227,1141,1066,768,647.

で表わされるユウロピウム錯体０．８５ｇを得た。この際の収率は７９％であった。なお、このものの赤外吸収スペクトルは次のとおりであった。
Ｅｕ（Ｌ１）₃（ｐｈｅｎ）；ＩＲ（ＫＢｒ）：２９５８，２９３３，２８７２，１６２７，１５９９，１５７３，１５４３，１４２８，１３９２，１２７０，１２２３，１１１８，７８０，７３１，６４８． A suspension of 0.18 g (0.50 mmol) of europium oxide, 0.60 ml of 12N hydrochloric acid and 30 ml of ethanol was refluxed until a homogeneous solution was obtained, and then 0.83 g of 3,4-dibutoxybenzoic acid (3. 2 mmol) and 0.19 g (0.5 mmol) of phenanthroline were added. Trimethylamine was added to this until the reaction solution became neutral, the precipitated white solid was filtered, washed with water and ethanol, and then dried under reduced pressure to obtain the formula.

0.85 g of a europium complex represented by the formula: The yield at this time was 79%. The infrared absorption spectrum of this product was as follows.
Eu (L1) ₃ (phen); IR (KBr): 2958, 2933, 2872, 1627, 1599, 1573, 1543, 1428, 1392, 1270, 1223, 1118, 780, 731, 648.

  The fluorescent rare earth metal complex of the present invention can be mixed with a synthetic resin, such as EVA, and used as a solar cell sealing material of a silicon crystal solar cell module.

Claims (7)

  A fluorescent rare earth metal complex graft-copolymerizable with a synthetic resin, which has an aromatic carboxylic acid having two adjacent alkoxyl groups as a substituent as a ligand.   The fluorescent rare earth metal complex according to claim 1, wherein the alkoxyl group is a butoxy group.   The fluorescent rare earth metal complex according to claim 1 or 2, wherein the aromatic carboxylic acid is benzoic acid.   A rare earth metal oxide is dissolved in a mixture of an organic solvent and an inorganic acid, and then an aromatic carboxylic acid having two adjacent alkoxyl groups as a substituent, an organic amine, and a neutralizing amount of a base are added to the reaction mixture. A method for producing a fluorescent rare earth metal complex capable of being graft-copolymerized with a synthetic resin, wherein the precipitated precipitate is separated.   The method for producing a fluorescent rare earth metal complex according to claim 4, wherein the inorganic acid is hydrochloric acid.   6. The method for producing a fluorescent rare earth metal complex according to claim 4, wherein the organic amine is a tertiary amine.   The method for producing a fluorescent rare earth metal complex according to claim 6, wherein the tertiary amine is phenanthroline.