JPH0521162A - Paste for el element - Google Patents

Abstract

PURPOSE:To improve tire brightness of an EL element by reducing the production time of the EL element because of curable by radial rays and high curing rate and by eliminating the need for a solvent and by increasing dielectric constant. CONSTITUTION:There is provided fluorescent substance paste for forming the light emitting layer of a dispersion type EL or high dielectric paste for forming an insulator layer. Its binder uses polyol with a carbon number of at least 4 which allows curing by radiation and has at least one each of cyanoethyl group and vinyloxy carbonyl methyl group.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phosphor paste for forming a light emitting layer of an electroluminescence device and a high dielectric paste for forming an insulator layer.

[0002]

2. Description of the Related Art Dispersed electroluminescence (E
L) In general, the element uses a metal foil such as aluminum foil as a back electrode, and a high dielectric paste in which an inorganic high dielectric powder such as titanium oxide or barium titanate is dispersed in an organic dielectric binder is applied on the back electrode. Then, the reflective insulator layer is formed by solidifying, and a phosphor paste in which phosphor powder such as zinc sulfide is dispersed in an organic dielectric binder is applied thereon to form a light emitting layer by solidifying,
Finally, it has a structure in which a transparent electrode such as ITO (a mixture of indium oxide and tin oxide) is installed as a counter electrode, and the phosphor emits light when an AC voltage is applied between both electrodes.

A dispersion type EL element in which only a light emitting layer is sandwiched between a back electrode and a transparent electrode is also used.

Conventionally, solvent-drying type pastes or thermosetting type pastes have been used as these pastes in the production of such dispersion type EL elements, and all of them have been set by heat. However, these solvent-drying type pastes or thermosetting type pastes require about 1 to 2 hours for curing, and the coating, drying process or coating and curing to obtain an insulator layer or a light emitting layer having a predetermined thickness. Since the process may be repeated several times, it has been desired to shorten the solidification process.

On the other hand, a radiation-curable high-dielectric paste or phosphor paste has been developed, which makes it possible to shorten the solidification process. (JP-A-1-2005
No. 95). Japanese Patent Application Laid-Open No. 1-200595 discloses a radiation-curable high-dielectric paste or phosphor paste, and as a binder thereof, for example, a (meth) acrylic acid ester derivative having a cyanoalkyl group and a cyanoalkoxyalkyl group are included. A (meth) acrylic acid ester derivative or a (meth) acrylic acid amide derivative having a cyanoalkyl group is also disclosed.

[0006]

However, JP-A 1-20
The compound disclosed in No. 0595 is a low molecular weight compound obtained by cyanoalkylating and (meth) acryloylating a polyol having 3 or less carbon atoms, and such a compound has a relatively slow solidification rate and insufficient solidification. There was a drawback that was. The present invention is an improvement over the above-mentioned drawbacks of the prior art.

[0007]

The present invention provides a phosphor powder for EL, radiation-solidifiable at least one cyanoethyl group and at least one vinyloxycarbonylmethyl group.

[0008]

[Chemical 1]

A phosphor paste for forming a light emitting layer of a dispersion type EL device characterized by having a polyol having 4 or more carbon atoms as a main component, and an inorganic high dielectric powder, which can be solidified by radiation, and at least one Provided is a high dielectric paste for forming an insulating layer of a dispersion-type EL device, which comprises, as a main component, the above-mentioned cyanoethyl group and at least one vinyloxycarbonylmethyl group-containing polyol having 4 or more carbon atoms. It is a thing.

As the phosphor powder for the phosphor paste EL, a commonly used one can be used. For example, zinc sulfide powder may be mixed with an activator such as copper or manganese, and a coactivator such as chloro, bromine, or aluminum. The added one is used. Phosphor powder is paste
It is preferably 50 to 90 parts by weight in 100 parts by weight.

As a binder for a phosphor paste, a polyol having 4 or more carbon atoms (hereinafter, cyanoethylated, vinyloxycarbonyl) which can be solidified by radiation and has at least one cyanoethyl group and at least one vinyloxycarbonylmethyl group. The use of a methylated polyol) is a feature of the invention. A polyol having no cyanoethyl group has a low dielectric constant, and the brightness of an EL device using this binder is lowered. Further, a polyol having no vinyloxycarbonylmethyl group cannot be solidified by radiation.

The cyanoethylated and vinyloxycarbonylmethylated polyols of the present invention rapidly solidify by radiation, but those having a dielectric constant of 10 or more (25 ° C., 1 KHz) after solidification are desirable.

In the present invention, a polyol having a relatively high molecular weight of 4 or more, preferably 6 or more, is used.

As the polyol having 4 or more carbon atoms, a polyhydric alcohol having 4 to 60 carbon atoms, a natural polymer having a hydroxyl group having 61 or more carbon atoms, a chemically modified polymer having a hydroxyl group or a synthetic polymer having a hydroxyl group is preferable. Examples of the polyhydric alcohol having 4 to 60 carbon atoms include monosaccharides and oligosaccharides (having a molecular weight of less than 1600) having 4 to 60 carbon atoms. As monosaccharides, chain sugar alcohols such as erythritol, xylitol, sorbitol, mannitol, and galactitol, cyclic sugar alcohols such as inositol, and cyclic reducing sugar acetals such as methyl glucoside and methyl mannoside are used. As oligosaccharides, saccharose and multisaccharide are used. It includes disaccharides such as tall and 3 to 10 saccharides such as α, β, γ-cyclodextrin. Starch and cellulose containing glucose as a constituent sugar as a hydroxyl group-containing natural polymer having 61 or more carbon atoms,
Polysaccharides such as pullulan, dextran, guar gum, tara gum, etc., which have mannose and galactose as constituent sugars (molecular weight
1600 or more) is exemplified. Polymers chemically modified with natural polysaccharides such as hydroxyethyl cellulose and dihydroxyethyl starch are shown as hydroxyl group-containing chemically modified natural polymers, and polyvinyl alcohol (poval) and ethylene-vinyl acetate copolymers are shown as hydroxyl group-containing synthetic polymers. Saponified products (Eval) and the like are preferably used.

The number of cyanoethyl groups and vinyloxycarbonylmethyl groups may be one or more, and the substitution rate (value obtained by dividing the number of moles of cyanoethylated or vinyloxycarbonylmethylated hydroxyl groups by the number of moles of all hydroxyl groups) is It is chosen arbitrarily. Further, it may be a mixture of polyols having various substitution ratios of cyanoethyl group and vinyloxycarbonylmethyl group. Further, the cyanoethylated or vinyloxycarbonylmethylated polyol may be used alone, but when the viscosity is too high (for example, when the polyol is a polymer and is a solid), cyanoethyl is used within a range that does not hinder the curing rate from the viewpoint of workability. It may be mixed with a low-molecular compound that can be solidified by radiation, such as vinyloxycarbonylmethylated polyol, such as 2-hydroxyethyl acrylate.

Particularly, it is preferable to mix it with a radiation-curable low molecular weight compound which can be solidified by radiation and is substituted with at least one or more cyanoethyl groups from the viewpoint of improving workability and dielectric constant. Examples of such compounds include 2-
(2-Cyanoethoxy) ethyl acrylate, N, N-
Examples include bis (2-cyanoethyl) acrylamide and 3-cyanopropyl acrylate. It is desirable that such a compound is mixed at 80% by weight or less.

Of course, the cyanoethylated, vinyloxycarbonylmethylated polyols of the present invention include a mixture, for example, cyanoethylated, vinyloxycarbonylmethylated polymer polyols (having 60 or more carbon atoms) and cyanoethylated,
It may be a mixture with a vinyloxycarbonylmethylated low molecular weight polyol (having 4 to 60 carbon atoms).

The cyanoethylated, vinyloxycarbonylmethylated polyol is generally obtained by vinyloxycarbonylmethylating a cyanoethylated polyol obtained by cyanoethylating a polyol. Cyanoethylation of a polyol is easily carried out by Michael-adding to the hydroxyl group contained in the polyol, acrylonitrile in an amount equal to or less than the hydroxyl group equivalent. Further, vinyloxycarbonylmethylation of cyanoethylated polyol is described in, for example, N.I. By reacting vinyl chloroacetate in the presence of 1,8-diazabicyclo [5,4,0] -7-undecene (DBU), potassium carbonate and sodium carbonate in a solvent such as N-dimethylformamide, acetone or acetonitrile. can get.

The cyanoethylation substitution rate and vinyloxycarbonylmethylation substitution rate were calculated from the values obtained by measuring the residual hydroxyl value by the acetic anhydride-pyridine method which is a conventional method.

The cyanoethylated and vinyloxycarbonylmethylated polyol may have a hydroxyl group remaining after the reaction,
All hydroxyl groups may be cyanoethylated or vinyloxycarbonylmethylated.

The cyanoethylation substitution rate is preferably 10 to 95%, the vinyloxycarbonylmethylation substitution rate is 80% or less,
Particularly, 5 to 50% is preferable.

High-dielectric paste As the inorganic high-dielectric powder, those conventionally used can be used, but for example, barium titanate, lead titanate, strontium titanate and the like are preferably used. The inorganic high dielectric powder is preferably 50 to 90 parts by weight in 100 parts by weight of the paste.

The radiation-curable polyol having at least one cyanoethyl group and at least one vinyloxycarbonylmethyl group having at least one carbon atom and having 4 or more carbon atoms used as the binder is the same as that used in the phosphor paste. Is used.

Also in the case of the high dielectric paste, the cyanoethylated or vinyloxycarbonylmethylated polyol may be used alone or as a mixture with another radiation-curable compound, similar to the phosphor paste. In particular, it can be solidified by radiation,
In addition, it is preferable to mix with a low molecular weight compound having at least one or more cyanoethyl groups in terms of workability and dielectric constant.

Both the phosphor paste and the high-dielectric paste may contain an organic high-dielectric substance in order to increase the dielectric constant, if necessary. As such an organic high dielectric substance, a substance having a dielectric constant of 10 or more (1 KHz, 25 ° C.) is preferable, and cyanoethylated ethylene vinyl alcohol copolymer, cyanoethylated polyvinyl alcohol, cyanoethylated dihydroxypoval, cyanoethylated cellulose, cyanoethylated hydroxyalkyl. Cellulose, cyanoethylated hydroxyethyl cellulose, cyanoethylated pullulan, etc. are used.

Further, these pastes may contain a spacer, a photosensitizer and the like.

Examples of the spacer include epoxy resin, polystyrene, nylon, glass and the like having a particle size of 10 to 50 μm.

Representative examples of the photosensitizer include benzoin isopropyl ether, 1-hydroxy-cyclohexyl-phenyl ketone (manufactured by Ciba-Geigy; trade name Irgacure-184), 2-hydroxy-2-methyl-1-.
Examples thereof include phenylpropan-1-one (manufactured by Merck & Co .; trade name Darocur 1173), benzyl dimethyl ketal (manufactured by Ciba-Geigy; Irgacur-651) and the like. The amount of the photosensitizer added is usually 0.5 to 5% by weight based on the cyanoethylated or vinyloxycarbonylmethylated polyol.
It is preferable to add.

Examples of the radiation used in the present invention include electron beams and ultraviolet rays, which may be irradiated alone or in the order of ultraviolet rays and electron beams.

Further, the phosphor paste and the high induction conductor paste of the present invention are pastes that can be solidified by radiation, but can be solidified by heating by adding a peroxide.

EL Element The dispersion type EL using the phosphor paste and the high dielectric paste of the present invention is manufactured by a known method, for example, a method described in JP-A-1-200595. As an example, a high dielectric paste is applied to a back electrode that has been subjected to a lead-out process for terminals, and after application, it is solidified by irradiation of radiation to form an insulating layer. Next, a phosphor paste was applied onto the insulator layer, and a transparent electrode, which had been subjected to a terminal lead-out process in advance, was pressed onto the paste layer. Then, the laminate is irradiated with radiation from the transparent electrode side to be solidified to form a light emitting layer. After solidification, a synthetic resin film such as nylon is applied with the external lead wires pulled out, and the whole is sealed with a fluororesin film.

The dispersion type EL device thus obtained can exhibit high brightness by applying an AC voltage or a DC voltage to its terminal.

Further, if necessary, the phosphor paste or high dielectric paste of the present invention may be combined with a conventional heat-solidifying (solvent drying type or thermosetting) phosphor paste or high dielectric paste to form an EL device. It can also be manufactured. For example, the phosphor paste of the present invention may be a heat-setting type high dielectric paste, or a combination of the high-dielectric paste of the present invention and a heat setting type phosphor paste. It is also possible to add an organic solvent as needed.

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited to the examples as long as the gist thereof is not exceeded.

[0035]

【Example】

[Synthesis Example 1] 30 g of saccharose, 15 g of water, and 30% N in a 300 ml three-necked flask equipped with a stirrer, a cooler, and a thermometer.
1.9 g of aOH was charged and stirred. Dichloromethane (30 g) and acrylonitrile (55 g) were added to this, and the mixture was added for 50 hours.
The reaction was carried out at ° C. Return the reaction mixture to room temperature and add chloroform.
90 ml was added, and the mixture was extracted and washed twice with 100 ml of water. The chloroform layer was dried over magnesium sulfate and then concentrated to obtain 65 g of cyanoethylated saccharose (cyanoethylation rate: 62.5%).

6.3 g (0.052 mol) of vinyl chloroacetate was added dropwise to a reaction solution containing 10.57 g (0.017 mol) of cyanoethylated saccharose obtained above and 100 ml of dichloromethane. While cooling here, 7.9g of DBU (0.052
Mol) was added, and the mixture was stirred at room temperature for 3 hours. Neutralize with acetic acid,
100 ml of water was added and the mixture was extracted and washed 3 times. A polymerization inhibitor (tributylhydroquinone) was added to the dichloromethane layer and concentrated to obtain 12 g of vinyloxycarbonylmethylated product.

[Synthesis Example 2] Cyanoethylated pullulan (Shin-Etsu Chemical, cyanoresin CR-S, cyanoethylation rate 85
%) 20 g, acetone 200 ml, potassium carbonate 10 g, and chlorovinyl acetate 9.6 g were heated to reflux for 2 hours. After neutralizing the reaction solution, pour it into 1 liter of water while stirring,
The separated product was further crystallized twice from acetone-water for purification. The protrusion was dissolved in a small amount of acetone, a polymerization inhibitor (tributylhydroquinone) was added, and the mixture was vacuum dried at 50 ° C. to obtain 21 g of vinyloxycarbonyl methylated product.

[Synthesis Example 3-5] Sorbitol, xylitol, poval and erythritol were cyanoethylated and vinyloxycarbonylmethylated in the same manner as in Synthesis Example 1 or 2.

Table 1 shows the respective substitution rates of the cyanoethylated and vinyloxycarbonylmethylated polyols obtained in Synthesis Examples 1 to 5.

[Reference Example] 100 g of the cyanoethylated vinyloxycarbonylmethylated polyol of the above Synthesis Examples 1 to 5
2g of photo-initiator (Ciba Geigy; Irgacure 184) was added, stirred and mixed, then degassed and poured into a dish with a diameter of 6 cm to a thickness of 1 mm. The surface was 10 cm below a metal halide lamp with an output of 80 W / cm It was irradiated until the stickiness disappeared.

Table 1 shows the dielectric constant (25 ° C., 1 KHz) after curing.

[0042]

[Table 1]

Table 2 shows the irradiation time (curing time) until the stickiness disappeared.

The cyanoethylated vinyloxycarboxymethylated pullulan and poval of Synthesis Examples 2 and 5 were 2-
(2-cyanoethoxy) ethyl acrylate and 50/50
The measurement was carried out for (parts by weight) mixed and dissolved by heating. Further, for comparison, the curing time was similarly measured for a mixture of 2- (2-cyanoethoxy) ethyl acrylate, 2- (2-cyanoethoxy) ethyl acrylate and neopentyl acrylate. The results are shown in Table 2.

[0045]

[Table 2]

From Table 2, the curing rates of cyanoethylated and vinyloxycarbonylmethylated polyols are shown in Comparative Example 2
It can be seen that it is extremely faster than (2-cyanoethoxy) ethyl acrylate. Also, 2- (2-cyanoethoxy)
A mixture of ethyl acrylate and neopentyl acrylate having no cyano group has a high curing rate but a low dielectric constant.

Example 1 360 g of a phosphor powder for electroluminescence (Type 723 manufactured by GTE) was mixed with 50 g of cyanoethylated and vinyloxycarbonylmethylated saccharose and 50 g of 2- (2-cyanoethoxy) ethyl acrylate and well dispersed. Then, 2 g of a photosensitizer (manufactured by Merck & Co .; Darocur-1173) was further added, mixed by stirring, and then defoamed. 1 g of epoxy beads was dispersed in this suspension as a spacer to prepare a phosphor paste for forming a light emitting layer of a dispersion type electroluminescence device.

Example 2 A phosphor paste was manufactured in the same manner as in Example 1 except that 50 g of cyanoethylated and vinyloxycarbonylmethylated saccharose was changed to 50 g of cyanoethylated and vinyloxycarbonylmethylated sorbitol.

Example 3 A phosphor paste was prepared in the same manner as in Example 1 except that 50 g of cyanoethylated and vinyloxycarbonylmethylated saccharose was replaced with 50 g of cyanoethylated vinyloxycarbonylmethylated xylitol.

[Example 4] Barium titanate powder 200 g
Was mixed with 50 g of cyanoethylated, vinyloxycarbonylmethylated saccharose and 50 g of 2- (2-cyanoethoxy) ethyl acrylate and well dispersed, and 2 g of a photosensitizer (Merck & Co .; Darocur 1173) was mixed and stirred. Then, defoaming was performed to produce a high-dielectric paste for forming an insulating layer of a dispersed electroluminescent element.

Example 5 A high dielectric paste was manufactured in the same manner as in Example 4 except that cyanoethylated and vinyloxycarbonylmethylated saccharose was changed to cyanoethylated vinyloxycarbonylmethylated sorbitol.

Example 6 A high dielectric paste was produced in the same manner as in Example 4 except that cyanoethylated vinyloxycarbonylmethylated saccharose was replaced with cyanoethylated vinyloxycarbonylmethylated xylitol.

An example of manufacturing an EL element will be shown below.

[Examples 7 to 9] The high dielectric paste of Example 4 was applied to the back electrode of a 100-micron-thick aluminum plate by screen printing, and ultraviolet rays were irradiated for 5 seconds from a 4KW metal halide lamp to form a binder. Was solidified to form an insulating layer. This thickness was 30 microns. Subsequently, after applying the phosphor paste of Example 1 on the insulator layer by screen printing, a transparent conductive film with a thickness of 75 μm having ITO vapor deposited on one side is attached to the lead terminals so that it does not contain air. Crucifixion, then
Ultraviolet rays were irradiated from the transparent electrode side for 5 seconds by a 4 KW metal halide lamp to solidify the binder to form a 40 μm thick phosphor layer. A lead terminal was attached to the back electrode, a nylon film for catching water was laminated on both front and back surfaces, and the whole was sealed with a fluorine film to obtain an EL device. (Example 7).

In the same manner as in Example 7, the phosphor paste of Example 2 and the high dielectric paste of Example 5 were used for EL.
A device was manufactured (Example 8). Also, in the same manner as in Example 3,
An EL device was manufactured using the phosphor paste of Example 1 and the high dielectric paste of Example 6 (Example 9). The results shown in Table 3 were obtained by applying an AC voltage of 100 V and 400 Hz to each EL element of Examples 7 to 9.

[0056]

[Table 3]

[Example 10] 20 g of cyanoethylated, vinyloxycarbonylmethyl pullulan as a phosphor paste,
80 g of cyanoethylated xylitol, phosphor (Type 723)
200g, Irgacure 184 2g, Epoxy beads 1g
As a high dielectric paste using the above composition, 20 g of cyanoethylated, vinyloxycarbonylmethylated pullulan, 80 g of cyanoethylated xylitol, barium titanate powder 2
An EL device was obtained in the same manner as in Example 7 except that the composition of 00 g and Irgacure 184 2 g was used. However, an applicator was used for coating. The thickness of each layer was 50 μm for the light emitting layer and 30 μm for the insulating layer. 100V, 400H to this EL element
An alternating voltage of z was applied. The brightness was 110 cd / m ² .

[0058]

EFFECT OF THE INVENTION The phosphor paste and the high-dielectric paste of the present invention can be solidified by radiation and have 4 or more carbon atoms having at least one cyanoethyl group and at least one vinyloxycarbonylmethyl group. Since the binder containing a polyol as a main component is used, the curing speed is high, the light emitting layer and the insulating layer of the dispersion type EL device can be easily formed, and the time for manufacturing the EL device can be shortened. In addition, there is no danger of fire, explosion or solvent poisoning due to the use of solvent,
An insulator layer and a light emitting layer having a desired film thickness can be easily obtained.

Further, since it has a cyanoethyl group, it has a high dielectric constant. Further, it can be used by mixing with a UV-curable cyanoethylated polyol, and a paste having a high curing rate and a high dielectric constant can be obtained, and the brightness is further improved.

Claims (8)

[Claims] 1. A phosphor powder for electroluminescence, which is solidified by radiation, and which contains, as a main component, a polyol having 4 or more carbon atoms and having at least one or more cyanoethyl groups and at least one or more vinyloxycarbonylmethyl groups. A phosphor paste for forming a light emitting layer of a dispersion-type electroluminescence element, which is characterized in that: 2. The phosphor paste according to claim 1, wherein the polyol having 4 or more carbon atoms is a monosaccharide or an oligosaccharide. 3. The phosphor paste according to claim 1, wherein the polyol having 4 or more carbon atoms is a hydroxyl group-containing natural polymer, a hydroxyl group-containing chemically modified polymer or a hydroxyl group-containing synthetic polymer. 4. A phosphor powder for electroluminescence, a polyol having at least one cyanoethyl group and at least one vinyloxycarbonylmethyl group, which can be solidified by radiation and have at least one vinyloxycarbonylmethyl group, and a carbon number of 4 or more, and other than the polyol. A phosphor paste for forming a light emitting layer of a dispersion-type electroluminescence device, which comprises a mixture of compounds that can be solidified by radiation as a main component. 5. An inorganic high-dielectric powder and a radiation-curable polyol having at least one or more cyanoethyl groups and at least one or more vinyloxycarbonylmethyl groups as a main component and having a carbon number of 4 or more. A high dielectric paste for forming an insulating layer of a distributed electroluminescence device, which is characterized in that. 6. The high dielectric paste according to claim 5, wherein the polyol having 4 or more carbon atoms is a monosaccharide or an oligosaccharide. 7. The high dielectric paste according to claim 5, wherein the polyol having 4 or more carbon atoms is a hydroxyl group-containing natural polymer, a hydroxyl group-containing chemically modified polymer or a hydroxyl group-containing synthetic polymer. 8. A polyol having at least one or more cyanoethyl groups and at least one or more vinyloxycarbonylmethyl groups, which can be solidified by irradiation with an inorganic high-dielectric powder and has at least one vinyloxycarbonylmethyl group, and a polyol other than the above polyols. A high-dielectric paste for forming an insulator layer of a dispersion-type electroluminescence device, which comprises a mixture of compounds that can be solidified by radiation as a main component.