JPH04188596A - Moistureproof film and dispersion type el panel - Google Patents

Abstract

PURPOSE:To provide high moistureproofness and prevent oxidation of metal foil or drop of the adhering force by controlling the moisture permeability of a plastic film which is a base of moistureproof film, and laminating this with metal foil which does not easily admit passage of water and/or vapor. CONSTITUTION:A foil made of a metal or alloy having a specific gravity of no less than 2.7 (18 deg.C) and a rigidity factor of 0.27X10<6>kg/cm<2> (18 deg.C) is formed over a plastic sheet containing 1-20wt.% hydrophobic resin particles having a mean particle dia. between 0.5-5mum, and a thermo-plastic adhesive layer is formed over one major surface of this laminated of plastic sheet and foil. Thereby an anti-moisture film having excellent moistureproof is obtained, which prevents oxidation of metal foil and drop of the adhering force.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Application Field) The present invention provides a moisture-proof film that is most suitable as an outer skin film for a display device, etc. that requires moisture resistance, and a film constructed using this moisture-proof film. The present invention relates to a distributed electroluminescent panel (hereinafter referred to as a distributed EL panel).

(Prior art) Dispersion type EL panels, especially film-type flexible distribution type EL panels, have features such as uniform surface emission, being thin and lightweight, and being able to form curved surfaces. They have become indispensable as backlights for liquid crystal display devices in personal computers and word processors, and as the prices of these OAp devices fall, it is desired that the prices of distributed EL panels also fall.

The structure of a conventional distributed EL panel will be explained using FIG. In the same figure, on a back electrode 1 made of aluminum foil or the like with an alumite layer formed on the surface, a white inorganic dielectric material such as barium titanate is contained in an organic dielectric material 2a such as n-anoethylbullulane or cyanoethylpohar. powder 2
reflective insulating layer 2 formed by mixing b, phosphor particles 3b mainly composed of zinc sulfide and organic fluorescent pigment 3C in organic dielectric 3a;
A light-emitting layer 3 formed by dispersing the light-emitting layer 3, and a transparent conductive film 4 made of a plastic film 4b having a transparent electrode 4a formed on the surface in contact with the surface of the light-emitting layer 3 are laminated. In this state, 100 to 120V is applied between the back electrode 1 and the transparent electrode 4b.
400) When an alternating current electric field of about 1z to 700Hz is applied, the organic dielectrics 2a and 3 emit light, or remain in this state.
a. The phosphor 3b is significantly deteriorated due to moisture absorption, and the light emitting characteristics are significantly impaired. For this purpose, a water-catching film 5 made of, for example, nylon 6, etc., such as a moisture-proof film 6 made of ethylene fluoride chloride as a main component, is laminated on the outer surfaces of the transparent conductive film 4 and the back electrode 1, respectively. is taking. That is, the moisture-proof film 6 is made of a polymer film whose main component is ethylene trifluorochloride, which is the most impermeable to moisture among various polymer films, and the water-absorbing film 5 is provided inside the film. It has a double moisture-proof structure that traps trace amounts of moisture that have passed through the contact layer of the moisture-proof film 6 before reaching the light-emitting layer 3 through the transparent conductive film 4. Note that 7 in the figure indicates an external lead attached to the back electrode 1 and the transparent electrode 4a.

However, the cost of such a moisture-proof structure is
It accounted for about half of the total cost of distributed EL panels, was an obstacle to lower prices, and was a cause of hindering wider adoption.

The structure of another conventional distributed type EL panel is shown in FIG. A compensation electrode 9 made of metal foil such as , Cu, or AI is laminated via a thermoplastic adhesive or adhesive 8, and this is electrically connected to the transparent electrode 4a on the surface of the transparent conductive film 4. It suppresses internal vibrations and prevents noise. Such noise countermeasures are also an obstacle to lower prices.

Therefore, a film made by laminating aluminum foil and polyethylene terephthalate (hereinafter referred to as PET), which is widely used in fields such as food packaging, and a thermoplastic adhesive layer on the surface is used as the moisture-proof film on the back electrode side. At the same time, attempts have been made to reduce the cost by using aluminum foil constituting the moisture-proof film as the compensation electrode.

However, as is clear from the moisture permeability measurement results of various films shown below, such AI/PETl single-layer type moisture-proof films have moisture-proof performance comparable to that of trifluorochloroethylene. The characteristics are due to the AI foil, and therefore, there is a problem in that moisture reaches the surface of the laminated AI foil, causing noise to increase over time. Therefore, there is a need for the development of a method for suppressing the moisture permeability of the PET layer portion without causing an increase in price.

Table 1 shows the measurement results of the moisture permeability of various films. Note that this measurement was carried out under the conditions of 40'C190XRH in accordance with J15-Z-0208, and the numbers within 0 in the table indicate the thickness (μm) of each layer.

Table 1 (Problem to be solved by the invention) In this way, the low-cost moisture-proof films that have been proposed so far have moisture-proof performance due to the metal foil that makes up the laminate, so the metal foil may corrode during use. However, there was a problem that the adhesion force decreased and the anti-vibration performance deteriorated.

The present invention was made to solve these problems, and by suppressing the moisture permeability of the plastic film that is the base of the moisture-proof film, and laminating it with a metal foil that does not easily allow moisture to pass through, In addition to achieving high moisture-proofing performance equivalent to or better than difluorochloroethylene, this film also prevents oxidation and deterioration of adhesive strength of the metal foil. The purpose is to obtain a type EL panel.

[Structure of the Invention] (Means for Solving the Problems) The moisture-proof film of the present invention comprises a plastic sheet containing hydrophobic resin particles with an average particle size of 0.5 to 5 μm in a range of 1 to 20% by weight, and Formed in a plastic sheet, specific gravity 2.7 or higher (18℃), rigidity 0.27X 106
kg/cm or more (18°C), and a thermoplastic adhesive layer formed on at least one main surface of a laminate of the plastic sheet and the foil made of the metal or alloy. It is characterized by:

Further, the dispersion type EL panel of the present invention includes an EL element in which at least a light emitting layer is sandwiched between a pair of electrodes, one of which is an optically transparent electrode, and a surface of the EL element having the optically transparent electrode. The moisture-proof film is provided on the outer surface opposite to the moisture-proof film.

In addition to PET, the transparent plastic sheet used in the present invention includes polyether sulfone (PES),
Polyarylate, polycarbonate (PC), polymethyl methacrylate (P M MA), polystyrene, polysulfone, polyether ether ketone (PEEK)
), but the film is not limited to these examples as long as it is a flexible film. Alternatively, a thinner film of conventional trifluorochloroethylene may be used. Furthermore, a stack of these plastic sheets may also be used.

Further, the thickness of the plastic sheet is not particularly limited, but from the viewpoint of flexibility and shape retention, it is desirable that it is 20 to 100 μm, preferably 30 to 75 μm.

The hydrophobic resin particles used in the present invention are not particularly limited to the material, as long as they have an average particle size in the range of 0.5 to 10 μm and are hydrophobic, or may be non-melting silicone. It is preferable to use resin particles.

The non-melting silicone resin particles are made by micronizing polyorganosiloxane having a three-dimensional network structure due to siloxane bonds. The organic group bonded to the silicon atom of polyorganosiloxane is a -valent substituted or unsubstituted hydrocarbon group, such as an aliphatic hydrocarbon group such as a methyl group or an ethyl group, or an aromatic hydrocarbon group such as a phenylene group. , an unsaturated hydrocarbon group having a vinyl group is exemplified. The organic group bonded to the silicon atom of the polyorganosiloxane is an important factor involved in the hydrophobicity and refractive index of the non-melting silicone resin particles, and it is desirable to change it depending on the plastic sheet used. For example, when adding to PET, it is desirable to introduce a phenyl group. Silicone resin can generally be produced by hand as a silicone varnish made by dissolving an initial condensate in a suitable solvent, but the non-melting type silicone resin mentioned here has an average particle size in the range of 0.5 to 5 μm without containing a solvent. It is a powder-like substance that has been thermoset and is substantially insoluble and infusible.

The hydrophobic resin particles used have an average particle size of 0.5 to 5 μm.
The thickness is preferably in the range of 0.75 to 2 μm. If the average particle size exceeds 5 μm, the resulting plastic sheet will have insufficient surface flatness. Also,
When the average particle size is less than 0.5 μm, it is difficult to obtain monodisperse particles.

Further, the shape of the hydrophobic resin particles is preferably spherical, particularly those having a sphericity f of 0.8 or more expressed by the following formula (I).

f-A π 4 m, t...(1
) (In the formula, A is the cross-sectional area of the polymer powder, Dl, and 8 is the longest diameter of the cross-section of the polymer powder.) The sphericity f of this hydrophobic resin particle is determined by the slipperiness when making a plastic sheet and the plastic It particularly affects the surface properties of the sheet.

Further, the amount of hydrophobic resin particles to be blended must be 1 to 20% by weight, and preferably 3.0 to 18.0% by weight, based on the plastic sheet. If the content is less than 1% by weight, sufficient suppression of the moisture permeability of the plastic sheet cannot be expected. On the other hand, if it exceeds 20% by weight, the surface flatness will be significantly reduced.

By adding hydrophobic resin particles that satisfy the above shape conditions to the plastic sheet in the above content, the distribution density of the hydrophobic resin particles becomes high near the surface of the plastic sheet. This acts as a barrier to moisture infiltration,
Increases the moisture resistance of plastic sheets.

The plastic sheet of the present invention may be subjected to surface treatments such as UV103 light cleaning treatment, corona discharge treatment, plasma treatment, glow discharge treatment, reverse sputtering treatment, and surface roughening treatment, or any known surface treatment prior to lamination with foil made of metal or alloy. Anchor processing may be applied.

The foil made of metal or alloy used in the present invention has a specific gravity of 2.7 or more (18°C), a rigidity of 0.27X 106 kg
It is a foil made of a metal or alloy with a temperature of /C- or higher (18°C). Specific gravity and rigidity are less than 2.7 (18℃), 0
．． Below 27 x 106 kg/cJ (18°C), sufficient suppression of noise cannot be expected when a foil made of this metal or alloy is used as a compensation electrode.

The thickness of the foil made of metal or alloy is not particularly limited, and may be between 20 and 10 mm from the viewpoint of flexibility and shape retention.
It is desirable that the thickness be 0 μm, preferably in the range of 30 to 75 μm.

Methods for laminating a foil made of a metal or alloy and a plastic sheet include a method in which a sheet of thermoplastic adhesive layer component as described below is created and dry lamination is performed by sandwiching the sheet between the sheets, and a method in which a foil made of a metal or alloy or a plastic sheet is laminated. A method can be used in which the thermoplastic adhesive layer component is dissolved in an organic solvent and applied to either one of the plastic sheets, or the thermoplastic adhesive layer component is melt-extruded and laminated, and the other is laminated thereon.

In the present invention, a thermoplastic adhesive layer is formed on one side of a plastic sheet laminated with metal or alloy foil in order to wrap the dispersed EL element.

The thermoplastic adhesive layer in the present invention refers to a polymer layer that can be bonded by heating and pressure, and includes polyolefins such as polyethylene and polypropylene, polyesters, polyamides, acrylic resins such as ethylene-vinyl acetate copolymers, and acrylic esters. , polyvinyl acetal resin, phenol-modified epoxy resin, and copolymers and mixtures thereof. In distributed EL panels, the intrusion of moisture from the adhesive surface is also a factor in deterioration, so it is desirable to use a thermoplastic adhesive layer with low moisture permeability as much as possible.

Methods for laminating this thermoplastic adhesive layer include a method in which the thermoplastic adhesive layer component is dissolved in an organic solvent and applied, a method in which the thermoplastic adhesive layer component is melt-extruded and laminated,
A method may be used in which a sheet of thermoplastic adhesive layer components is prepared in advance and dry laminated.

The thickness of the thermoplastic adhesive layer is 10 to 150 μm, especially 30 to 150 μm.
80 μm is desirable.

(Function) In the present invention, a plastic sheet containing hydrophobic resin particles with an average particle diameter of 0.5 to 5 μm in a range of 1 to 20% by weight, a specific gravity of 2.7 or more (18°C), and a rigidity of 0 ．．
27X 1.06kg/c♂ or more (18℃) It has a laminated structure with foil made of metal or alloy, so it is a moisture-proof film with excellent moisture-proof performance at a low price without sacrificing flexibility. Can you get it? In addition, the distributed EL panel of the present invention using this moisture-proof film has a low price and a long service life.Furthermore, when the foil made of metal or alloy constituting the moisture-proof film is used as a compensation electrode, it is possible to reduce the cost during use. It is possible to obtain a distributed EL panel with integrated compensation electrode and moisture-proof film that exhibits less deterioration in moisture-proof performance, that is, less deterioration in vibration-proof performance.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing the structure of a moisture-proof film according to an embodiment of the present invention. Further, an example of a dispersion type EL panel according to the present invention produced using this moisture-proof film is shown in the cross-sectional view of FIG.

In FIG. 1, lla and llb are average particle diameters of 0.5 to
Hydrophobic resin particles such as non-melting silicone resin powder in the range of 5 μm] 2 are contained in the range of 1 to 20% by weight, and these two plastic sheets) 11a, 1.1b or have a specific gravity of 2. .7 or more (at 18°C) and a rigidity of 0.27×106 kg/c- or more (at 18°C) and is integrally bonded to both main surfaces of a foil 13 made of metal or alloy. A thermoplastic adhesive layer 14 is further integrally formed on one main surface of this laminate, that is, on the outer surface of one plastic sheet lla. 15 in the figure is
The adhesive layer is shown.

Further, in FIG. 2, reference numeral 16 indicates a back electrode made of aluminum foil or the like with an alumite layer formed on the surface. A reflective insulating layer 17 made of a mixture of powder 17b of a white inorganic dielectric material such as barium, and a light emitting layer made of a dispersion of phosphor particles 18b mainly made of zinc sulfide and an organic fluorescent pigment 18C in an organic dielectric 18a. 18. A plastic film 19 with a transparent electrode 19a formed on the surface in contact with the surface of the light emitting layer 18.
Transparent conductive films 19 made of B are laminated in order. A water-trapping film 20 made of, for example, nylon 6 is laminated on both sides of these laminates, and the moisture-proof film 2 of the above structure according to the present invention is further wrapped around them.
1 is laminated on the back electrode 16 side, and a moisture-proof film 22 containing, for example, trifluorochloroethylene as a main component is laminated on the transparent conductive film 9 side, and are integrally bonded by thermocompression. Although not shown, a current collector electrode is provided on the surface of the transparent electrode 19H by applying Ag paste or the like, and a power source 2 is connected to the current collector electrode and the back electrode 17.
An extraction electrode (not shown) for connection to 3 is attached to each.

Next, a method for producing a moisture-proof film and a dispersion type EL panel having the above-mentioned structure will be explained using specific examples.

Hydrophobic resin particles 1 with an average particle size in the range of 0.5 to 5 μm
The production of plastic sheets 11a and 1'lb containing 1 to 20% by weight of 2 will be explained.

That is, for example, dimethyl terephthalate and ethylene glycol, manganese acetate as a transesterification catalyst,
Using antimony trioxide as a polymerization catalyst and phosphorous acid as a stabilizer, an organic group bonded to the silicon atom of a polyorganosiloxane with an average particle size of 0.8 to 1.08 m and a sphericity of 0.87 to 0.93 is used. Polymerization is carried out in a conventional manner except that 10% by weight of non-melting silicone resin powder 12 using phenyl groups is added to obtain PET pellets having intrinsic viscosities of o and eO of 0.65 to 0.65.

Next, after drying the PET pellets at 170°C for 3 hours, they were fed to an extruder hopper and heated to a melting temperature of 280 to 300°C.
The molten polymer is extruded through a 1+on+ slit onto a rotating cooling drum with a surface roughness of about 0.3S and a surface temperature of 20°C to obtain an unstretched film with a thickness of 200 μm.

The unstretched film thus obtained was preheated at 75°C, then heated between rolls at low and high speeds, rapidly cooled, then fed to a stenter, and stretched in the transverse direction at a temperature of 100 to NO°C for 3.
A two-wheel stretched film is obtained by stretching 0 times. Subsequently, the obtained two-wheel stretched film was heated at a temperature of 200 to 210°C for 5 to 1
Heat set for 0 seconds to obtain a heat set biaxially stretched film with a thickness of 40 μm.

Then, the heat-set two-wheeled stretched film to which the non-melting type silicone resin powder with a thickness of 40 μm has been added is coated with urethane resin on both main surfaces of a foil 13 made of metal or alloy, for example, a metal foil made of A1 with a thickness of 30 μm. A moisture-proof film having the above structure according to the present invention is obtained by adhering an unstretched polypropylene with a thickness of 508° C., which will become the thermoplastic adhesive layer 14, on one of the heat-set biaxially stretched films using a urethane resin. is completed.

The moisture permeability of the moisture-proof film created in this way is J
15-Z-0208+: Table 2 shows the results measured under the conditions of 40° C. and 90% RH. As a comparative example, a laminated film was prepared in the same manner as in the above example except that no non-melting silicone resin powder was used, and the moisture permeability of this film was also measured in the same manner.

The results are also shown in Table-2.

Table 2 Next, a method for manufacturing the dispersed EL panel shown in FIG. 2 using the moisture-proof film produced by the above method will be described.

First, a binder solution containing cyanoethyl pullulan and cyanoethylpoval dissolved in N,N-dimethylformamide (DMF) was placed on the back electrode 16 made of aluminum foil with an alumite layer of 1 to 2 μm formed on its main surface. After coating a reflective insulating paste in which barium titanate powder with a thickness of 8 to 1 μm is dispersed by screen printing or the like, drying is performed at 120 to 170° C. to remove DMF, and a reflective insulating layer 17 with a thickness of 30 to 40 μm is formed. Form.

Next, on this reflective insulating layer 17, a luminescent paste prepared by dispersing a zinc sulfide phosphor and an organic fluorescent pigment in an inder solution was applied by screen printing or the like.
Drying at ~170°C to remove DMF,
A light emitting layer 17 having a thickness of μm is formed.

On the other hand, after printing a thermosetting Ag paste on the transparent electrode 19a of the transparent conductive film 19 by screen printing,
The current collector electrode is formed by baking at 150° C. for 30 minutes and thermosetting, and an extraction electrode made of phosphor bronze or the like is temporarily fixed to a predetermined position of the current collector electrode and the back electrode 16 with PET tape or the like.

After this, using a thermal laminator, the roll surface temperature was 140
-170℃, linear pressure 5~20kg/cm, feed rate 10~
The transparent electrode 19a and the light emitting layer 18 are bonded together under the condition of 50 cm/min. Furthermore, a thermal laminator is used on the outside of the transparent conductive film 19 and the back electrode 16, and the roll surface temperature is 120 to 150°C and the linear pressure is 5 to 10 kg/cf.
fl and a feed rate of 30 to 100 cITlZ, the water-catching film 20 with a thermoplastic adhesive layer is attached to the nylon 6 film with the thermoplastic adhesive layer facing inward.

Then, the moisture-proof film 21 according to the present invention is applied to the back electrode 17.
Using a thermal laminator, place the trifluorochloride moisture-proof film 22 on the transparent electrode 19a side, and set the roll surface temperature to 110 to 1.
50℃, linear pressure 5-15 dazzle/cn+, feed speed 10-70
The dispersion type EL panel according to the present invention is completed by laminating it on the outside of the water absorbing film 20 under the conditions of cm/min.

The dispersion type EL panel manufactured in this way was heated at 40°C.
A life test was conducted by applying 95% RI (11OL 700 Hz) under high temperature and high humidity. The results are shown in Fig. 3 (luminance attenuation curve) and Fig. 4 (change in noise).

Note that the figure shows a case where a film prepared in the same manner as in the example except that the non-melting silicone resin powder described above was not used was used as the moisture-proof film 21 on the back electrode 16 side (comparative example 1), Also shown are the results when a conventional trifluorochloride moisture-proof film was also used as the moisture-proof film 21 on the back electrode 16 side (Comparative Example 2).

As is clear from these figures, the distributed EL panel of the present invention has the same lifespan as the conventional product using a moisture-proof film using trifluorochloroethylene, which accounts for the largest proportion of the cost, and is inexpensive. It was confirmed that it is possible to reduce noise, and good results were also obtained in terms of noise generation.

[Effects of the Invention] As explained above, in the moisture-proof film of the present invention, a moisture-proof film with excellent moisture-proof performance can be obtained at a low cost without sacrificing flexibility. Furthermore, the distributed EL panel of the present invention using this moisture-proof film can be lowered in price and has a longer service life. Distributed type E with integrated compensation electrode and moisture-proof film, which has less deterioration in moisture-proof performance, that is, less deterioration in vibration-proof performance.
L panel can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the structure of a moisture-proof film according to an embodiment of the present invention, FIG. 2 is a cross-sectional view showing the structure of a distributed EL panel using the moisture-proof film according to the present invention, and FIG. Figure 4 is a diagram showing the life characteristics of a distributed EL panel using the moisture-proof film according to the invention, Figure 4 is a diagram showing its noise characteristics, and Figures 5 and 6 are diagrams showing the life characteristics of a distributed EL panel using a conventional moisture-proof film. FIG. 3 is a cross-sectional view showing the structure. 11a, llb...Plastic sheet 12...Hydrophobic resin particles 13...Foil made of metal or alloy 14...Thermoplastic adhesive layer 16...Back electrode 17...Reflective insulating layer 18...
...Light emitting layer 19a...Transparent electrode 21...Moisture-proof film Applicant: Toshiba Corporation Toshiba Electronic Device Engineering Co., Ltd. Agent: Patent attorney Suyama Sa-2, Co., Ltd.] Prefecture 214 Figure 3 Negative U 5 (・2nd 6th mouth

Claims (2)

[Claims] (1) Hydrophobic resin particles with an average particle size of 0.5 to 5 μm
A plastic sheet containing in the range of 20% by weight, and a specific gravity of 2.7 or more (
a foil made of a metal or alloy with a rigidity of 0.27 x 10^6 kg/cm^2 or more (at 18 °C); and at least one of the laminates of the plastic sheet and the foil made of the metal or alloy. A moisture-proof film comprising a thermoplastic adhesive layer formed on a surface thereof. (2) an EL element in which at least a light emitting layer is sandwiched between a pair of electrodes, one of which is an optically transparent electrode, and an outer surface of the EL element opposite to the surface having the optically transparent electrode; A distributed EL panel comprising the moisture-proof film according to claim 1.