JP2939141B2 - High dielectric graft polymer composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is useful as a highly dielectric graft polymer composition, more particularly as a binder for organic dispersion type electroluminescence (EL) devices and as a dielectric material for film capacitors, and has a particularly high dielectric constant. Composition comprising graft polymer excellent in moisture absorption resistance, organic dispersion type EL using such high dielectric graft polymer composition
The present invention relates to a device and a method for producing the above graft polymer.

[0002]

2. Description of the Related Art A binder for an organic electronic material, for example, an organic dispersion type EL device, is:
It is required to have characteristics such as high dielectric properties, low hygroscopicity for prolonging life, invariance of electrical characteristic values with temperature (heat resistance), and high adhesiveness to phosphors and electrode surfaces. On the other hand, among these, as the organic polymer used for the binder for the organic dispersion type EL element, (1) cyanoethylated polymer having a large number of hydroxyl groups such as polyvinyl alcohol, cellulose or derivatives thereof, pullulan, and (2) cyanoethylated A homo- or copolymer of an acrylic monomer, (3) a homo- or copolymer of vinylidene fluoride (vinylidene fluoride-based fluoro rubber) and the like are used.

However, the cyanoethylated compound of the above (1) has a large hygroscopicity, and is an organic dispersion type EL device (only EL device).
The device has a short life span (decrease in luminance and luminous efficiency due to light emission).
The device itself must be hermetically sealed with a moisture-impermeable transparent material, and yet its life is not sufficient, and it cannot be used at all for a so-called packageless type EL device without a hermetically sealed seal. The polymer of the above (2) has improved hygroscopicity compared to the cyanoethylated compound of the above (1), and the effect of improving the life can be seen in the EL device which is hermetically sealed, but is still not practical in the packageless type EL device. I do not endure. Further, the vinylidene fluoride-based fluororubber of the above (3) has low hygroscopicity and is particularly used for a packageless type EL element. However, it has a serious disadvantage that the dielectric constant is insufficient and sufficient luminance is hardly obtained. . Therefore,
A blend of the cyanoethylated compound (1) or the polymer (2) and the vinylidene fluoride-based fluororubber (3) may be used, but they are not compatible with each other.
Cannot be used immediately after separation.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies on polymers having a high dielectric constant and excellent moisture absorption resistance, and found that the polymers containing vinylidene fluoride-based fluororubber having a low moisture absorption rate. The inventors have found that, when a cyanoethylated acrylic monomer having a high dielectric constant is graft-introduced to a fluorine-based polymer, the resulting graft polymer has a high dielectric constant and can maintain a low moisture absorption rate, thereby completing the present invention.

That is, the present invention provides a fluorine-containing polymer having the formula:

Embedded image (Wherein ¹ ≦ m ≦ n−1, m is 1 to 3, R ¹ is H or C
H ₃ and R ² are a linear or branched alkylene group which may have at least one of an oxygen atom, a phenylene group, a hydrogenated phenylene group and an amino group). A highly dielectric graft polymer composition comprising a graft polymer obtained by polymerization, and an organic dispersion type EL device comprising a back electrode, a reflective insulating layer, a light emitting layer and a transparent electrode laminated in this order. In the organic dispersion type EL device and the fluorine-containing polymer, wherein the highly dielectric graft polymer composition is used as a binder for each of a reflective insulating layer and a light emitting layer, a cyanoethylated compound represented by the above formula It is intended to provide a method for producing a graft polymer comprising graft-polymerizing an acrylic monomer. .

[0006] The fluorine-containing polymer used in the present invention is:
Vinylidene fluoride (VDF), hexafluoropropylene (HFP), chlorotrifluoroethylene (CTF
E) one or more homopolymers and copolymers of a fluorinated monomer selected from the group of tetrafluoroethylene (TFE), pentafluoropropylene (PFP), perfluoromethyl vinyl ether (PFMUE), and the like;
And a copolymer of at least one of the fluorine-based monomers and at least one of the copolymerizable monomers described below. In particular, polyvinylidene fluoride and vinylidene fluoride (V
DF) and other fluorinated monomers (HFP, CTF
E, TFE, PFP and PFMUE)
A copolymer with a seed (hereinafter referred to as a VDF copolymer), so-called vinylidene fluoride-based fluororubber, is preferred. When a VDF copolymer is used, the VDF copolymer
Is generally 50 to 85 mol%, and the VDF copolymer is preferably set to be a rubbery region. Further, a fluorine-containing polymer having a radical active site containing iodine, bromine, or the like is preferable because it is easily graft-polymerized.

[0007] The cyanoethylated acrylic monomer (hereinafter referred to as cyanoethyl monomer) used in the present invention can be produced according to the following procedure. That is, first, the formula:

Embedded image Of acrylonitrile per mole of n-valent polyhydroxyl compound of formula (I), usually in the presence of an acid or alkali catalyst,
Michael addition reaction under the conditions of 0 to 100 ° C. and 1 to 48 hours yields the formula:

Embedded image To obtain a cyanoethyl compound. Here, the relationship between n and m is
It is set so that 1 ≦ m ≦ n−1, and the resulting cyanoethyl compound has (n−m), that is, one or more hydroxyl groups remaining in the molecule. Note that R ² represents a residue of the polyhydroxyl compound excluding the hydroxyl group.

The polyhydroxyl compounds include, for example, ethylene glycol, propylene glycol,
-Methyl-1,3-propanediol, 1,3-butylene glycol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, triethylene glycol, bisphenol A,
Examples include hydrogenated bisphenol A, 1,4-dimethylolcyclohexane, glycerin, trimethylolethane, trimethylolpropane, trishydroxymethylaminomethane, and pentaerythritol, and glycerin and pentaerythritol are particularly preferred.

Next, (nm) mole of (meth) acrylic acid is added to the remaining hydroxyl groups of the cyanoethyl compound at 50 to 150 ° C. for 4 to 48 hours in the presence of an acid catalyst. By carrying out the esterification reaction (dehydration reaction), a cyanoethyl monomer having no residual hydroxyl group can be obtained.

[0010] The graft polymer in the present invention is obtained by graft polymerization in the presence of an organic solvent or other liquid medium if a cyanoethyl monomer is required for the above-mentioned fluorinated polymer, that is, using a usual radical polymerization initiator. Radical polymerization method or radiation (γ
, A bulk polymerization, a solution polymerization, etc. (radiation polymerization method). In this case, the amount of the cyanoethyl monomer to be used may be generally selected in the range of 10 to 90% by weight, preferably 20 to 70% by weight, based on the total amount of the fluorine-containing polymer. If it is less than 10% by weight, the dielectric constant will not be sufficiently high, and if it exceeds 90% by weight, the hygroscopicity tends to increase.

As the above-mentioned organic solvent or other liquid medium, an organic solvent such as acetone, methyl ethyl ketone, γ-butyrolactone, ethyl acetate, butyl acetate, tetrahydrofuran, dimethylformamide, N-methylpyrrolidone, etc. is suitable. It is also possible to polymerize in a dispersed state in another organic solvent which does not dissolve the fluorine-containing polymer.

When the above graft polymerization is carried out, examples of the radical polymerization initiator used in a usual radical polymerization method include peroxides (ketone peroxide, benzoyl peroxide, peroxyketal, hydroperoxide, dialkyl peroxide). , Diacyl peroxide, peroxyester, peroxydicarbonate, etc.) and azo [2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis (2-cyclopropyl Propionitrile), 2,2'-
Azobis (2,4-dimethylvaleronitrile), 2,2'-
Azobisisobutyronitrile, 2,2'-azobis (2-
Methylbutyronitrile), 1,1′-azobis (cyclohexane-1-carbonitrile), 1-[(1-cyano-1-
Methylethyl) azo] formamide, 2-phenylazo-
4-methoxy-2,4-dimethylvaleronitrile]. In the radiation polymerization method using radiation, the above-mentioned polymerization initiator is not necessarily required.

In addition, in order to suppress side reactions such as control of molecular weight or cross-linking during the polymerization, aliphatic compounds such as mercaptans (for example, n-butyl mercaptan, octyl mercaptan, dodecyl mercaptan, benzyl mercaptan, cyclohexyl mercaptan, etc.) are used. , Aromatic,
Alicyclic ones) can also be used.

In the graft polymerization, in addition to the cyanoethyl monomer, if necessary, the copolymerizable monomer is usually added in an amount of about 50 parts by weight or less based on 100 parts by weight of the cyanoethyl monomer (the same applies hereinafter). It may be used in proportions. The copolymerizable monomer here is
It is not particularly distinguished from the copolymerizable monomer described in the definition of the fluorine-containing polymer, and common specific examples include acrylates (e.g., methyl acrylate, ethyl acrylate, propyl acrylate, n-
Butyl acrylate, isobutyl acrylate, amyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, n-
Octyl acrylate, etc.); methacrylates (e.g., methyl methacrylate, ethyl methacrylate,
n-butyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, tridecyl methacrylate, benzyl methacrylate, cyclohexyl methacrylate, tetrahydrofurfuryl methacrylate, 2-methoxyethyl methacrylate, 2-ethoxyethyl methacrylate, etc.); aromatic vinyl compound [ For example, styrene, α-methylstyrene, chloromethylstyrene, vinyltoluene,
Vinylnaphthalene, vinyl (alkyl) phenols, etc.]; alicyclic to aromatic hydrocarbon-based (meth) acrylates [eg, dicyclopentenyl (meth) acrylate,
Tricyclodecanyl (meth) acrylate, isobornyl
(Meth) acrylate, cyclohexyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, benzyl (meth) acrylate, etc.]; fluoroalkyl (meth) acrylate [for example, 2,2,2-trifluoroethyl (meth) acrylate, 2 , 2,3,3-tetrafluoropropyl (meth) acrylate, 2- (perfluoro-3
-Methylbutyl) ethyl (meth) acrylate, 2,2,3,
3,3-pentafluoropropyl (meth) acrylate,
1,1,1,3,3,3-hexafluoropropyl (meth) acrylate, octafluoropentyl (meth) acrylate, etc.]; (meth) acrylamide; aliphatic or alicyclic or aromatic hydrocarbon N- Substituted (meth) acrylamide
[For example, N-dimethylacrylamide, N-dibutylacrylamide, N-diphenylacrylamide and the like];
Other vinyl alcohol esters, acrylonitrile, methacrylonitrile, acrylic acid, methacrylic acid,
Maleic anhydride, maleic acid and its esters, fumaric acid and its esters, itaconic acid and its esters, allyl alcohol and its esters, vinyl chloride, vinylidene chloride, vinyl pyridine, vinyl pyrrolidone, vinyl alkyl ethers, hydrofluoric acid Vinylidene cyanide, vinylidene cyanide, monovinyl compounds such as styrene sulfonic acid, divinylbenzene, (meth) acrylates of polyhydric alcohols to polyhydroxyl compounds, allyl alcohol esters of polybasic acids, vinyl alcohol esters of polybasic acids, Polyvinyl compounds such as allyl (meth) acrylate and compounds having one or more mercapto groups in the molecule, disulfide compounds, 4-methacryloxyethyl trimellitic anhydride, acid phosphooxyethyl methacrylate And vinyl acetate, vinyl propionate, vinyl versatate, vinyl pyridine, vinyl pyrrolidone, butadiene and the like.

Further, when performing radiation polymerization using γ-rays, it is preferable to use an acid acceptor for capturing HF that may be generated, for example, calcium hydroxide, magnesium oxide, lead oxide, calcium oxide, or the like. .

The highly dielectric graft polymer composition according to the present invention comprises the above graft polymer and, if necessary, a resin such as a usual UV-curable resin composition, thermosetting resin composition, or thermoplastic resin composition; It is composed of a system in which fillers, dyes and pigments, conventional additives and the like are mixed in appropriate amounts.

The organic dispersion type EL device according to the present invention comprises a back electrode, a reflective insulating layer, a light emitting layer, and a transparent electrode, which are laminated in this order, and each of the reflective insulating layer and the light emitting layer therein. The high dielectric graft polymer composition is used as a binder. As a specific production method, for example, (i) the above-mentioned high dielectric graft polymer composition and inorganic high dielectric
An organic solvent mixture of (e.g., titanium oxide, barium titanate, barium zirconate, barium stannate, strontium titanate powder) is applied, dried by heating to form a reflective insulating layer, and then formed on the reflective insulating layer. The above high dielectric graft polymer composition and phosphor powder (for example, zinc sulfide, zinc selenide, Cu, Mn, Al,
An organic solvent mixture (which is obtained by adding Cl, Br, etc.) is applied and heated and dried to form a light emitting layer, and then the transparent electrodes are overlaid and thermocompression-bonded, or (ii) the above (i) In the same manner as in (1), after separately forming a reflective insulating layer and a light-emitting layer on each of the back electrode and the transparent electrode, the two electrodes are arranged such that the reflective insulating layer of the back electrode and the light-emitting layer of the transparent electrode face each other. A method of thermocompression bonding may be used. Examples of the organic solvent used above include N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone, γ-butyrolactone; ethylene glycol monoethyl ether acetate, propylene glycol monoethyl ether Glycol ether acetates such as acetate and ethylene glycol monobutyl ether acetate; cyclohexanone, isophorone and the like.

[0018]

According to the composition of the present invention having the above constitution, it is possible to satisfy both the high dielectric property required for a binder for an organic dispersion type EL device and the low moisture absorption property for a long life. Also, as an application, the insulating layer of such an EL element,
In addition to the binder for the light emitting layer, application development to film capacitor dielectric materials, polymer batteries, and pyroelectric materials is conceivable.

[0019]

Next, the present invention will be described more specifically with reference to examples and comparative examples. Examples 1 to 5 (1) Production of cyanoethyl monomer To 136.15 g (1 mol) of pentaerythritol was added 188 g of a 4% sodium hydroxide solution, and the mixture was stirred in a four-necked flask. To this, 164.1 g (3 mol) of acrylonitrile was added dropwise, and the Michael addition reaction was completed while adjusting the reaction temperature to 40 to 45 ° C. After the reaction, the reaction solution was transferred to a separating funnel, washed with water, and then extracted with methylene chloride, and 59 g of a cyanoethyl compound obtained by distilling off methylene chloride.
(0.2 mol), 52 g (0.6 mol) of methacrylic acid, 3.2 g of p-toluenesulfonic acid, 0.03 g of hydroquinone as a polymerization inhibitor and 200 g of benzene were added, and an ester reaction was carried out under reflux. Excess methacrylic acid is washed away with water to obtain a cyanoethyl monomer. The identity of the cyanoethyl monomer was confirmed using IR and NMR.

(2) Production of Graft Polymer (Radiation Polymerization by γ-Ray) When the components shown in the following Table 1 are blended and irradiated with 20 kg of γ-ray by cobalt 60, a milky white graft polymer solution is obtained. . A mixed solution of methanol / water (1/1, weight ratio) was added to the graft polymer solution to precipitate the graft polymer, and the washed and dried product was measured for dielectric constant, dielectric loss tangent, and moisture absorption. The dielectric constant and the dielectric loss tangent were determined by applying an organic solvent solution of graft polymer / ethylene glycol monoethyl ether acetate on a 1 mm thick aluminum plate and drying the film at 120 ° C. for 30 minutes by vacuum depositing aluminum on an approximately 100 μm thick film. The sample was determined using an LCZ meter, and the moisture absorption was determined by applying the same organic solvent solution to a 25 × 50 × 1 mm slide glass plate at 120 ° C.
40 ° C., 90%
The saturated moisture absorption at RH was determined by the weight increase method. The results are also shown in Table 1.

[0021]

[Table 1] Note * 1) Vinylidene fluoride fluororubber manufactured by Daikin Industries, Ltd. (VDF / HFP, specific gravity 1.81, Mooney viscosity about 66, containing iodine which is a radical active site in the molecule) * 2) DuPont, USA Vinylidene fluoride fluororubber * 3) Kyoeisha Chemical Co., Ltd. 2,2,2-trifluoroethyl methacrylate

Examples 6 to 11 (Solution polymerization) The components shown in Table 2 below were charged into a separable flask, and the mixture was stirred at 80 ° C. for 3 hours under nitrogen gas introduction to carry out polymerization. obtain. A mixed solution of methanol / water (1/1, weight ratio) was added to this graft polymer solution to precipitate the graft polymer, which was then washed and dried. The dielectric constant was determined in the same manner as in Examples 1 to 5 / (2) above. , Dielectric loss tangent and moisture absorption were measured. The results are also shown in Table 2.

[0023]

[Table 2] Note * 4) Methacrylic acid ester of the following formula manufactured by Hitachi Chemical Co., Ltd.

Embedded image

Comparative Examples 1 and 2 Vinylidene fluoride fluororubber (Daiel G-801) used in the above Examples was used as Comparative Example 1, and a homopolymer of cyanoethyl monomer ("M" manufactured by Sunstar Giken Co., Ltd.) was used as Comparative Example 2. −6164A ”), the dielectric constant, the dielectric loss tangent, and the moisture absorption were measured, and the results are shown in Table 3 below.

Table 3 Dielectric constant Dielectric loss tangent Moisture absorption (%) Comparative Example 1 9.6 0.011 0.46 〃 2 17.3 0.027 2.66

From the above results, the graft polymer of the present invention has a higher dielectric constant than vinylidene fluoride-based fluororubber, exhibits a low moisture absorption close to that of the fluororubber, and is suitable as a binder resin for an organic dispersion type EL device. It is recognized that there is.

Examples 12 to 16 The graft polymers of Examples 2, 5, 6, 10, 10 and 11 were used, and this was blended with other components in the number of parts shown in Table 4 below. The composition and the composition for a light-emitting layer were formed, and then an organic dispersion type EL device was prepared according to the following procedure, and the light-emitting characteristics at the initial stage and after aging were evaluated. Procedure A composition for a light emitting layer was screen-printed on a glass plate on which indium oxide-tin oxide (ITO) was vapor-deposited and processed at 120 ° C.
Was dried in a hot air drier for 30 minutes to form a light emitting layer, and then the composition for a reflective insulating layer was screen-printed in the same manner.
After drying at 20 ° C. for 90 minutes to form a reflective insulating layer, aluminum is vacuum-deposited on the reflective insulating layer to form a back electrode, whereby an organic dispersion type EL element is manufactured.

Next, this organic dispersion type EL device was
The initial luminance (Cd / m ² ) and the luminous efficiency (Cd / W) are measured with a sine wave of −500 Hz using a luminance meter and a wattmeter. Furthermore, the organic dispersion type EL element was exposed at 75 ° C. under a high humidity of 40 ° C./90% RH without a moisture-proof package.
The luminance and the luminous efficiency after continuous lighting for 120 hours with a sine wave of -500 Hz are measured under the same conditions as in the initial case, thereby examining the deterioration state of the organic dispersion type EL element.
The results are also shown in Table 4.

The contents of the components shown in Table 4 are as follows, and the graft polymer was dissolved in advance with the solvent shown in Table 4 before use. Graft polymer A: Example 2 B: 〃5〃 C: 〃6〃 D: １０10〃 E: １１11〃Phosphor powder Zinc sulfide-based phosphor powder manufactured by US Sylvania Co., trade name “Sylvania # 50” Solvent Ethylene glycol monoethyl ether acetate barium titanate powder "BT-100M" manufactured by Fuji Titanium Industry Co., Ltd.

[0029]

[Table 4]

Comparative Examples 3-4 Vinylidene fluoride-based fluoro rubber (Daikin Industries, Ltd.)
Co., Ltd. “Daier G-201”) or a homopolymer of cyanoethyl monomer (“M-616” manufactured by Sunstar Giken Co., Ltd.)
An organic dispersion-type EL device was prepared in the same manner as in Examples 12 to 16 except that 4A ") was used, and the luminescence characteristics at the initial stage and after aging at 40 ° C./90% RH were measured. The measurement conditions and the continuous lighting conditions were the same as in Examples 12 to 16.
And the same. The results are shown in Table 5 below.

TABLE 5 After initial aging Comparative Example luminance luminous efficiency-luminance light emission efficiency 3 53 1.11 49 1.01 (DAI-EL G-201) 4 102 0.89 76 0.67 (M-6164A)

As described above, the organic dispersion type EL device using the graft polymer of the present invention has a higher luminance both at the initial stage and after aging than the organic dispersion type EL device using the vinylidene fluoride-based fluororubber of Comparative Example 3. And the luminous efficiency shows almost the same value. On the other hand, when compared with the organic dispersion type EL device of Comparative Example 4 using the cyanoethylacrylic polymer, the initial luminance is slightly lower, but the luminance decrease after aging is small. The luminous efficiency showed a high value both at the initial stage and after aging. Therefore, it is recognized that the organic dispersion type EL device using the graft polymer composition of the present invention is a long-life EL device having high luminance and low hygroscopicity.

Claims (8)

(57) [Claims] 1. A fluorine-containing polymer having the formula: (Wherein ¹ ≦ m ≦ n−1, m is 1 to 3, R ¹ is H or C
H ₃ and R ² are a linear or branched alkylene group which may have at least one of an oxygen atom, a phenylene group, a hydrogenated phenylene group and an amino group). A highly dielectric graft polymer composition comprising a graft polymer obtained by polymerization. 2. The highly dielectric graft polymer composition according to claim 1, wherein the amount of the cyanoethylated acrylic monomer is 10 to 90% by weight based on the total amount of the acrylic polymer and the fluoropolymer. 3. The fluorinated polymer is polyvinylidene fluoride, or hexafluoropropylene, chlorotrifluoroethylene, tetrafluoroethylene as vinylidene fluoride and another fluorinated monomer.
3. The highly dielectric graft polymer composition according to claim 1, which is a copolymer with at least one of pentafluoropropylene and perfluoromethylvinyl ether. 4. The high dielectric graft polymer composition according to claim 3, wherein the ratio of vinylidene fluoride in the copolymer of vinylidene fluoride and another fluorine-containing monomer is 50 to 85 mol%. 5. The highly dielectric graft polymer composition according to claim 1, wherein at least one copolymerizable monomer is used in addition to the cyanoethylated acrylic monomer used for the graft polymerization. 6. A cyanoethylated acrylic monomer 10.
The highly dielectric graft polymer composition according to claim 5, wherein 50 parts by weight or less of the copolymerizable monomer is used per 0 parts by weight. 7. An organic dispersion-type electroluminescent device comprising a back electrode, a reflective insulating layer, a light emitting layer, and a transparent electrode laminated in this order, wherein each of the reflective insulating layer and the light emitting layer is used as a binder. To 6
An organic dispersion-type electroluminescent device, characterized by using the highly dielectric graft polymer composition according to any one of the above. 8. A fluorine-containing polymer having the formula: (Wherein m, n, R ¹ and R ² have the same meanings as defined in claim 1), and a method for producing a graft polymer comprising graft-polymerizing a cyanoethylated acrylic monomer.