JP2742092B2 - Styrene copolymer - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a styrene-based copolymer, and more particularly, to a copolymer having a specific stereostructure composed of a styrene-based repeating unit and a 9-vinylanthracene repeating unit.

[Problems to be solved by conventional technology and invention]

Recently, so-called “light, thin, short,
Due to the demand for "small", flat displays have attracted attention, and liquid crystal displays (LCDs) and the like have been widely used. This LCD is a light-receiving type and has very low power consumption, so it is used for many purposes.
In particular, there are problems in contrast and response speed, and development of a light-emitting liquid crystal display has been desired. Several electroluminescent displays (ELDs) capable of large-capacity medium-sized light-emitting liquid crystal displays have been commercialized as promising ones. Zinc sulfide is widely used as the light emitting layer base material. The emission color of this zinc sulfide covers the main wavelength of visible light, but only the yellow-orange color has been put to practical use, and the other colors have low luminance and have not been put to practical use. Especially blue emission
Even in subsequent researches, no material having sufficient luminance for practical use has been developed, and it has been desired to develop a blue light-emitting material along with full color display.

By the way, the group of the present inventors has recently succeeded in developing a styrene-based polymer having high syndiotacticity, and further developed a styrene-based polymer obtained by copolymerizing this styrene monomer and other components ( JP-A-62-10
Nos. 4818 and 63-241009). These polymers and copolymers having a syndiotactic structure are excellent in heat resistance, chemical resistance and electrical properties, and are expected to be applied to various fields.

In view of the situation as described above, the present inventors have developed a high syndiotacticity styrene-based copolymer capable of emitting blue light and having properties as an organic polymer light-emitting material that can be used as a film as it is. In order to do so, we conducted intensive research and examination.

[Means for solving the problem]

As a result, the styrene-based monomer is copolymerized with 9-vinylanthracene, and the stereoregularity of the styrene-based repeating unit chain mainly has a target property of a novel copolymer having a syndiotactic structure. I found something. The present invention has been completed based on such findings.

That is, the present invention provides a compound represented by the general formula [I]: [Wherein, R represents a hydrogen atom, a halogen atom or a carbon atom of 20;
Or less hydrocarbon groups, and m represents an integer of 1 to 3.
When m is plural, each R may be the same or different. A styrene-based repeating unit represented by the formula: And a weight average molecular weight of 5,000 to 1,000,000, and a stereoregularity of a styrene-based repeating unit chain is mainly a syndiotactic structure. To provide a styrenic copolymer.

The styrenic copolymer of the present invention comprises a repeating unit represented by the general formula [I] and a repeating unit represented by the general formula [II] as described above, and is represented by the general formula [I]. The repeating unit represented by the general formula [I '] Wherein R and m are the same as above. ] It is derived from the styrenic monomer represented by Where:
R is a hydrogen atom, a halogen atom (for example, chlorine, bromine, fluorine, iodine) or 20 or less carbon atoms, preferably
10 to 1 hydrocarbon group (for example, a saturated hydrocarbon group (especially an alkyl group) such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group, or an unsaturated hydrocarbon group such as a vinyl group) is there. Specific examples of the repeating unit represented by the general formula (I) include styrene units; p-methylstyrene units; m-methylstyrene units; o-methylstyrene units; 2,4-dimethylstyrene units; and 2,5- Dimethylstyrene unit; 3,4-dimethylstyrene unit; 3,5-dimethylstyrene unit; p-ethylstyrene unit; m-ethylstyrene unit; alkylstyrene unit such as p-tert-butylstyrene unit, p-divinylbenzene unit m-divinylbenzene unit; trivinylbenzene unit; p-chlorostyrene unit; m-chlorostyrene unit; o-chlorostyrene unit; p-bromostyrene unit; m-bromostyrene unit; o-bromostyrene unit; p- Fluorostyrene unit; m
-Fluorostyrene unit; o-fluorostyrene unit; o-
Examples thereof include a halogenated styrene unit such as a methyl-p-fluorostyrene unit, and a mixture of two or more of these units for controlling the wavelength of color development.

On the other hand, the 9-vinylanthracene repeating unit represented by the general formula [II] is represented by the formula [II '] Derived from 9-vinylanthracene. In addition to the 9-vinylanthracene, a 9-vinylanthracene derivative that can be polymerized at the 9-position and the 10-position can also be used. In addition, this 9-vinyl anthracene repeating unit is:
It is effective in imparting luminescence to the copolymer. Other olefins, dienes, polar vinyl monomers and the like may be used in combination as long as the luminescence is not impaired.

In the copolymer of the present invention, the styrene-based repeating unit may be composed of two or more components. Therefore, it may be a binary, ternary or quaternary copolymer. The content of the 9-vinylanthracene repeating unit is 5 to 95 mol% of the whole copolymer, preferably
10-95 mol%. Here, when the content of the 9-vinylanthracene repeating unit in the copolymer is less than 5 mol%, the luminescent property cannot be sufficiently exhibited. On the other hand, if the content exceeds 95 mol%, the film-forming property is reduced.

Further, the copolymer of the present invention has a weight average molecular weight of 5,000.
It is 0 to 1,000,000, preferably 8,000 to 800,000. If the weight-average molecular weight is less than 5,000, the film-forming property is poor, and if it exceeds 1,000,000, there is a disadvantage that it is difficult to dissolve in a solvent at the time of film-forming. The molecular weight distribution is not particularly limited and may be wide or narrow.

The styrenic copolymer of the present invention is one in which a chain of styrenic repeating units mainly has a syndiotactic structure. Here, the predominantly syndiotactic structure in the styrenic polymer means a phenyl group or a substituted phenyl group whose stereochemical structure is mainly a syndiotactic structure, that is, a side chain with respect to a main chain formed from carbon-carbon bonds. Are alternately located in opposite directions (racemate), and their tacticity is quantified by nuclear magnetic resonance ( ¹³ C-NMR) using isotope carbon.

Tacticity as measured by ¹³ C-NMR method is determined by the abundance ratio of a plurality of continuous structural units (ie, the abundance ratio of a relative conformational relationship of continuous structural units). In the case of three, triads and in the case of five can be indicated by pentads, the term "having a predominantly syndiotactic structure" as used in the present invention means that in a chain of styrene-based repeating units, usually 75% As described above, those having a syndiotacticity of preferably 85% or more, or 30% or more, preferably 50% or more in racemic pentad are shown. However,
The degree of syndiotacticity varies slightly depending on the type of substituent and the content of each repeating unit.

In the styrenic copolymer of the present invention, there are various embodiments such as block copolymerization of styrene-based repeating units and 9-vinylanthracene repeating units, random copolymerization or alternating copolymerization, and block copolymers are particularly preferred. preferable.

The copolymer of the present invention can be produced by various methods using the styrene-based monomer represented by the general formula [I '] and the 9-vinylanthracene monomer represented by the formula [II'] as raw materials. Can be produced, for example, by copolymerizing in the presence of a catalyst containing (A) a titanium compound and (B) an alkylaluminoxane as main components.

The catalyst used for the production of this copolymer is disclosed in
As described in detail in -187708. Further, a titanium compound as the component (A) is more preferably a compound represented by the general formula TiR ¹ XYZ (wherein R ¹ represents a cyclopentadienyl group, a substituted cyclopentadienyl group or an indenyl group; Y and Z each independently represent a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 20 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, Represents up to 20 arylalkyl groups or halogen atoms. ] It is a titanium compound represented by these. The substituted cyclopentadienyl group represented by R ¹ in the formula has, for example, 1 to 6 carbon atoms.
A cyclopentadienyl group substituted by one or more alkyl groups, specifically a methylcyclopentadienyl group, 1,2-
Dimethylcyclopentadienyl group, pentamethylcyclopentadienyl group and the like. X, Y and Z each independently represent a hydrogen atom, an alkyl group having 1 to 12 carbon atoms (specifically, a methyl group, an ethyl group, a propyl group, an n-butyl group, an isobutyl group, an amyl group, an isoamyl group, Octyl group, 2-
An ethylhexyl group, etc.), an alkoxy group having 1 to 12 carbon atoms (specifically, a methoxy group, an ethoxy group, a propoxy group,
Butoxy group, amyloxy group, hexyloxy group, octyloxy group, 2-ethylhexyloxy group, etc., aryl group having 6 to 20 carbon atoms (specifically, phenyl group, naphthyl group, etc.), aryl having 6 to 20 carbon atoms It represents an oxy group (specifically, a phenoxy group or the like), an arylalkyl group having 6 to 20 carbon atoms (specifically, a benzyl group) or a halogen atom (specifically, chlorine, bromine, iodine or fluorine).

Specific examples of the titanium compound represented by such a general formula include cyclopentadienyl trimethyl titanium, cyclopentadienyl triethyl titanium, cyclopentadienyl tripropyl titanium, cyclopentadienyl tributyl titanium, methyl cyclopentadiene Enyltrimethyltitanium, 1,2-dimethylcyclopentadienyltrimethyltitanium, pentamethylcyclopentadienyltrimethyltitanium, pentamethylcyclopentadienyltriethyltitanium, pentamethylcyclopentadienyltripropyltitanium, pentamethylcyclopentadienyl Tributyltitanium, cyclopentadienylmethyltitanium dichloride, cyclopentadienylethyltitanium dichloride, pentamethylcyclopentadienylmethyltitanium dichloride, pentamethylcyclo Pentadienylethyl titanium dichloride, cyclopentadienyl dimethyl titanium monochloride, cyclopentadienyl diethyl titanium monochloride, cyclopentadienyl titanium trimethoxide, cyclopentadienyl titanium triethoxide, cyclopentadienyl titanium tripropoxy , Cyclopentadienyl titanium triphenoxide, pentamethylcyclopentadienyl titanium trimethoxide, pentamethylcyclopentadienyl titanium triethoxide, pentamethylcyclopentadienyl titanium tripropoxide, pentamethylcyclopentadienyl titanium Tributoxide, pentamethylcyclopentadienyl titanium triphenoxide, cyclopentadienyl titanium trichloride, pentamethylcyclopentadienyl titanium trichloride , Cyclopentadienylmethoxytitanium dichloride, cyclopentadienyldimethoxytitanium chloride, pentamethylcyclopentadienylmethoxytitanium dichloride, cyclopentadienyltribenzyltitanium, pentamethylcyclopentadienylmethyldiethoxytitanium, indenyltitanium Examples include trichloride, indenyl titanium trimethoxide, indenyl titanium triethoxide, indenyl trimethyl titanium, indenyl tribenzyl titanium and the like.

Among these titanium compounds, compounds containing no halogen atom are preferable, and in particular, a four-coordinate titanium compound in which at least one ligand is an unsaturated π-electron ligand as described above is preferable. preferable.

On the other hand, the alkylaluminoxane, which is the component (B) used together with the titanium compound, is a contact product of an alkylaluminum compound and water, and specifically has the general formula [In the formula, n represents a degree of polymerization, a number of 2 to 50, and R ² represents an alkyl group having 1 to 8 carbon atoms. A chain alkylaluminoxane represented by the general formula And a cyclic alkylaluminoxane having a repeating unit represented by the formula:

Generally, the contact product of alkyl aluminum such as trialkyl aluminum and water is, together with the above-described chain alkyl aluminoxane and cyclic alkyl aluminoxane,
Unreacted trialkylaluminum, a mixture of various condensation products, and molecules in which these are intricately associated with each other are various products depending on the contact conditions between the trialkylaluminum and water.

The reaction between the alkyl aluminum and water at this time is not particularly limited, and may be performed according to a known method. For example, (1) a method in which an alkyl aluminum is dissolved in an organic solvent and then brought into contact with water, (2) a method in which an alkyl aluminum is initially added during polymerization, and water is added later, and (3) a metal There is a method of reacting water of crystallization contained in a salt or the like, or water adsorbed on an inorganic substance or an organic substance with alkyl aluminum. The water may contain up to about 20% of ammonia, amines such as ethylamine, sulfur compounds such as hydrogen sulfide, and phosphorus compounds such as phosphite.

As the alkylaluminoxane used as the component (B), when a hydrated compound or the like is used after the above-mentioned contact reaction, the solid residue is separated by filtration, and the filtrate is subjected to a temperature of 30 to 200 ° C. under normal pressure or reduced pressure. It is preferable that the mixture is heat-treated at a temperature of preferably 40 ° C. to 150 ° C. for 20 minutes to 8 hours, preferably 30 minutes to 5 hours while distilling off the solvent.

In this heat treatment, the temperature may be appropriately determined depending on various conditions, but is usually in the above range. In general,
If the temperature is lower than 30 ° C., no effect is exhibited, and if it exceeds 200 ° C., thermal decomposition of the aluminoxane itself occurs, which is not preferable. Depending on the treatment conditions of the heat treatment, the reaction product is obtained as a colorless solid or solution. The product thus obtained can be dissolved or diluted with a hydrocarbon solvent, if necessary, and used as a catalyst solution.

A preferred example of such an alkylaluminoxane has a high magnetic field component of 50% or less in a methyl proton signal region based on an aluminum-methyl group (Al-CH ₃ ) bond observed by proton nuclear magnetic resonance absorption. . That is, when the above contact product is observed for proton nuclear magnetic resonance ( ¹ H-NMR) spectrum in a toluene solvent at room temperature, the methyl proton signal based on Al—CH ₃ is based on tetramethylsilane (TMS). In the range of 1.0 to -0.5 ppm. TMS proton signal (0 ppm) is Al-C
Because of the methyl protons observation area based on H _3, the Al-
The methyl proton signal based on CH ₃ was measured with reference to 2.35 ppm of the methyl proton signal of toluene based on TMS, and the high magnetic field component (ie, −0.1 to −0.5 ppm) and the other magnetic field components (that is, 1.0 to −0.5 ppm) were measured. 0.1 ppm), the high magnetic field component is 50% or less of the whole, preferably 45 to 5%.
% Can be suitably used as the component (B) of the catalyst.

The catalyst used in the production of the copolymer of the present invention comprises the above-mentioned components (A) and (B) as main components. In addition to the above, other catalyst components such as the general formula AlR ³ ₃ [ In the formula, R ³ represents an alkyl group having 1 to 8 carbon atoms. ], Or other organometallic compounds represented by the formula:

In using this catalyst, the ratio of the component (A) to the component (B) in the catalyst depends on the type of each component, the type of the styrene-based monomer represented by the general formula [I '] as a raw material, and other factors. It depends on the conditions and cannot be determined uniquely,
Usually, the ratio of aluminum in component (B) to titanium in component (A), ie, aluminum / titanium (molar ratio)
As, 10 ^6, preferably 10 to 10 ^4.

The copolymer of the present invention can be obtained by, for example, the above (A) and (B)
It can be obtained by copolymerizing a styrene-based monomer represented by the above general formula [I '] and 9-vinylanthracene represented by the formula [II'] in the presence of a catalyst containing the component as a main component. This copolymerization can be carried out by various methods such as bulk polymerization, solution polymerization and suspension polymerization. Solvents that can be used in the copolymerization include aliphatic hydrocarbons such as pentane, hexane and heptane, alicyclic hydrocarbons such as cyclohexane, benzene, toluene, and the like.
There are aromatic hydrocarbons such as xylene. The polymerization temperature is not particularly limited, but is usually 0 to 100 ° C, preferably 10 to 70 ° C. The polymerization time is 5 minutes to 24 hours, preferably 1 hour or more.

As described above, the copolymer of the present invention can be obtained by copolymerization of monomers corresponding to styrene-based repeating units and 9-vinylanthracene repeating units. Further, by using the obtained copolymer as a raw material and applying a separation, blending, or organic synthesis technique, an embodiment having desired stereoregularity and blue emission performance can be produced.

Further, in order to adjust the molecular weight of the obtained styrenic copolymer, it is effective to carry out the copolymerization reaction in the presence of hydrogen.

The styrenic copolymer obtained as described above has a high syndiotacticity of a styrenic repeating unit chain, but after polymerization, if necessary, is subjected to a deashing treatment with a washing solution containing hydrochloric acid and the like, and further washed, After drying under reduced pressure and washing with a solvent such as methyl ethyl ketone to remove soluble components, a styrene copolymer having extremely high syndiotacticity and high purity can be obtained.

〔Example〕

 Next, the present invention will be described in more detail with reference to examples.

Example 1 (1) of methylaluminoxane toluene 200ml glass vessel was purged with argon internal volume 500ml of copper sulfate pentahydrate _{(CuCO 4 · 5H 2 O)} 17.7g (71 mmol) and trimethyl aluminum 24 ml (250 mmol ) Was added and reacted at 40 ° C. for 8 hours. Thereafter, the solid component was removed, and toluene was further distilled off from the resulting solution under reduced pressure to obtain 6.7 g of a contact product. Its molecular weight measured by the freezing point depression method was 610.

Also, when the proton nuclear magnetic resonance spectrum of a high magnetic field component by the above-mentioned ¹ H-NMR measurement, that is, its proton nuclear magnetic resonance spectrum is observed in a toluene solution at room temperature, the methyl proton signal based on the (Al—CH ₃ ) bond is found to be tetramethylsilane. In the standard, it is found in the range of 1.0 to -0.5 ppm. For proton signal of tetramethylsilane which is (0 ppm) is in the observation area of the methyl proton based on the Al-CH ₃ bonds, methyl proton signal based on the Al-CH ₃ bonds of toluene in tetramethylsilane reference methyl proton signal 2.35 ppm is measured as a reference, and the high magnetic field component (ie, -0.1 to -0.5 ppm) and other magnetic field components (ie, 1.0
~ -0.1 ppm), the high magnetic field component
43%.

(2) Production of styrene-based copolymer 8 mmol of the aluminoxane obtained in (1) above as an aluminum atom was placed in a dry reaction vessel at room temperature under a nitrogen atmosphere, stirred, and then cyclopentadienyl titanium trichloride was added. After adding 0.01 mmol and further raising the temperature to 50 ° C. with stirring, a mixed monomer solution obtained by dissolving 10.0 g of 9-vinylanthracene (manufactured by Aldrich) in 5.74 ml of styrene and 10 ml of toluene was added, and a polymerization reaction was carried out for 4 hours. .

Thereafter, about 10 ml of methanol was added to terminate the polymerization. Further, the resultant was washed with a mixed solution of methanol and hydrochloric acid, filtered, and then washed three times with methanol. Thereafter, Soxhlet extraction was performed with methyl ethyl ketone in order to remove the monomer, followed by drying to obtain 4.5 g of a polymer as an extraction residue.

When the molecular weight of this polymer was measured by gel permeation chromatography, the weight average molecular weight was
The number average molecular weight was 12,000 and the number average molecular weight was 3,500.

(3) Analysis of polymer and measurement of physical properties (a) Melting point: The melting point of the polymer obtained in the above (2) was measured using a differential scanning calorimeter.
A peak was observed at ° C., suggesting that it contains a styrene chain and a 9,10-linked anthracene chain of a syndiotactic structure.

(B) Ultraviolet absorption spectrum (UV): the polymer obtained in the above (2), the vinylanthracene homopolymer obtained by the same operation as in the above (2) (without using styrene), and When the syndiotactic polystyrene obtained by the method described in -104818 was used as a chloroform solution and the ultraviolet absorption spectrum was observed, only the polymer obtained in the above (2) had a characteristic absorption of 246 nm, It is suggested that it is a copolymer.

(C) Proton nuclear magnetic resonance ( ¹ H-NMR): above (2)
The polymer obtained in was dissolved in deuterated chloroform, and ¹ H-NMR
Was measured. The result is shown in FIG. The signals in FIG. 1 can be assigned to protons a to g as follows,
The bound anthracene linkage was found to contain 67 mol%.

1.3ppm: a, 1.85ppm: b, 6.9 to 7.5ppm: c, 2.7ppm: d 5.9 to 6.0ppm: e, 6.9 to 7.3ppm: f 3.95ppm: g where a to g correspond to the following protons, respectively I do.

(D) Nuclear magnetic resonance ( ¹³ C-NMR) by isotope carbon: In order to obtain information on the stereoregularity of the styrene chain in the polymer, an aromatic C ₁ carbon signal of styrene was obtained by ¹³ C-NMR. Upon examination, a sharp signal was observed at 135.2 ppm as shown in FIG. 2, indicating that the sample had a syndiotactic structure. Since the styrene aromatic C ₁ carbon signal is not much affected by the copolymerization bond as compared with the syndiotactic styrene homopolymer, it can be inferred to be a block copolymer.

From the measurement results (a) to (d) above, it was found that this polymer had a styrene chain having a syndiotactic structure and a 9,10 bond anthracene chain.

(E) Fluorescence spectrum: The fluorescence spectrum was measured in order to obtain information on the emission color of a chloroform solution of this polymer (copolymer) and a solvent cast film, and the vinyl anthracene monomer. Each result is third
This is shown in FIGS. 4, 5 and 6.

The film forming property of this copolymer was extremely good, and the film could be formed by both ordinary solvent casting and spin coating. Comparing the respective fluorescence spectra, it was found that while the vinyl anthracene monomer had an ultraviolet-violet fluorescent color, the chloroform solution of the copolymer and the cast film exhibited indigo to blue-green fluorescence.

〔The invention's effect〕

The copolymer of the styrenic monomer having a syndiotactic structure and 9-vinylanthracene of the present invention has a blue fluorescent color related to blue light emission, can be easily formed into a film, and has a high film-forming property. It is a polymer. Therefore,
The copolymer of the present invention can be effectively used for an electroluminescent full color display device and the like.

[Brief description of the drawings]

FIG. 1 is the ¹ H-NMR spectrum of the copolymer obtained in the example, and FIG. 2 is its ¹³ C-NMR spectrum. FIGS. 3 to 5 are the fluorescence spectra of the chloroform solution and the solvent cast film of the copolymer obtained in the examples and the vinylanthracene monomer, respectively.

Claims (2)

(57) [Claims] 1. A compound of the formula [I] [Wherein, R represents a hydrogen atom, a halogen atom or a carbon atom of 20;
Or less hydrocarbon groups, and m represents an integer of 1 to 3.
When m is plural, each R may be the same or different. A styrene-based repeating unit represented by the formula: And a weight average molecular weight of 5,000 to 1,000,000, and a stereoregularity of a styrene-based repeating unit chain is mainly a syndiotactic structure. Styrene copolymer. 2. The styrenic copolymer according to claim 1, which has blue light emission.