JPH0451571B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a polychlorotrifluoroethylene (hereinafter referred to as PCTFE) film mainly used for moisture proofing, a method for producing the same, and an electroluminescent element (hereinafter referred to as an EL element) using the film. ) regarding. (Prior art) A moisture-proof film made of PCTFE, for example,
As described in Japanese Patent No. 57-128798, it is used as a sealing material for EL elements, and is also used for coating and sealing electrical parts, electronic parts, medical materials, drugs, etc. By the way, such PCTFE films conventionally have a melting point of about 210 to 220 degrees Celsius, which is about
Melt extruded into a film at a temperature 100℃ higher,
It is manufactured by a method in which the material is then rapidly cooled (hereinafter referred to as melt extrusion molding). And PCTFE obtained by this conventional method
The film flow rate (Melt Flow Rate) is approximately 7×
10 ^-2 cc/sec or more, and the crystallinity is about 50% or less. (Problems to be Solved by the Invention) As described above, PCTFE moisture-proof films have conventionally been manufactured by melt extrusion, but in recent years,
It has come to be required that the film has improved moisture-proofing performance. However, as long as melt extrusion molding is used, improvement in moisture-proof performance cannot be achieved as described below. PCTFE has a relatively high melt viscosity and poor fluidity, so in order to facilitate film forming during melt extrusion, the temperature during extrusion molding must be set to a high temperature far exceeding the melting point as described above. Therefore, partial decomposition and molecular weight reduction are inevitable. This resulted in partial decomposition and a decrease in molecular weight.
If PCTFE is not rapidly cooled after melt extrusion, its crystallinity will become too high and it will become brittle, making it more likely to crack due to impact or stress, so rapid cooling after extrusion was necessary. On the other hand, plastic films generally have higher crystallinity, lower water vapor permeability, and better moisture resistance, and PCTFE is no exception. Therefore, to improve the moisture resistance of PCTFE film,
Although it is desirable to increase the degree of crystallinity, it is not possible to achieve high crystallinity of the film using conventional melt extrusion. Therefore, the present invention has improved moisture-proof performance.
The present invention provides a PCTFE film and a method for manufacturing the same, and also provides a long-life EF element covered and sealed with the film. (Means for Solving the Problems) The present inventor conducted various studies to improve the moisture-proof performance of PCTFE film, and the flow value of the film (hereinafter referred to as
It has been found that the objective can be achieved by setting the MFR (referred to as MFR) to a predetermined value or less and the crystallinity to a predetermined value or more. Furthermore, the inventors have also discovered that a film having the above-mentioned physical properties can be obtained by a new manufacturing method different from conventional melt extrusion molding, leading to the completion of the present invention. That is, the PCTFE film according to the present invention has MFR
and crystallinity is 5×10 ^-2 cc/sec or less and
It is limited to 50% or more, and it is not yet clear why such a limitation improves moisture-proof performance, but as shown in the example below, its effect has been confirmed. It was done. Next, an example of the method for manufacturing the PCTFE film according to the present invention will be described. This method is characterized by compression molding PCTFE into a block shape, then slowly cooling this block shape so that its crystallinity becomes 50% or more, and then cutting the block shape into a film shape. That is. In this method, first, PCTFE powder or pellets are compressed into a block-like body such as a cylinder or cylinder. This compression molding
For example, this can be done by filling a cylinder with PCTFE powder or pellets, pressurizing and heating the cylinder. The pressure, temperature, and time during compression molding can vary depending on various factors, but usually the pressure is about 10 to 100 kg/cm ² , the temperature is about 230 to 280°C, and the heating and pressing time is about 30 to 300 minutes. It is. Note that commercially available PCTFE products can be used; specific examples include Daikin's "Daiflon CTFE" and 3M's "Kel-
F”, “Aclon” manufactured by Allied Fibers & Plastics
CTFE”, Produits Chimiques Ugine Kuhlman
``Voltalef'' etc. can be mentioned. In this method, the block-shaped body obtained as described above is then slowly cooled. This gradual cooling
This is to increase the crystallinity of PCTFE to 50% or more, and is usually carried out by cooling it to room temperature. During slow cooling, it is preferable to maintain the pressure during compression molding (pressure slow cooling), and more preferably to increase the pressure to about 250 to 400 kg/cm ² and cool slowly. Therefore, gradual cooling can be performed within the cylinder used for compression molding. The block-shaped body cooled to room temperature in this manner is then cut into a film shape of a predetermined thickness using a lathe or the like. According to the method of the present invention, the temperature during compression molding can be set lower than in the conventional method.
It does not cause decomposition of PCTFE, and high crystallization can be achieved through the slow cooling process. Therefore, the obtained PCTFE film has improved moisture-proofing performance and high mechanical strength. Furthermore, another example of the method for manufacturing the PCTFE film according to the present invention will be described. This method is characterized by carrying out block forming by compression, slow cooling and cutting in the same manner as described above, and then rolling the cut film. This rolling can be performed, for example, by passing the cut film between at least one pair of rolling rolls, and the rolling temperature is usually 100 to 200°C. The degree of rolling can be indicated by the change in film thickness before and after rolling. In this method, the film thickness after rolling is 10 to 10 times that before rolling.
It is preferable to set it to about 70%. The above rolling may be carried out using one cut film, but it is also possible to stack two or more cut films and roll them. When a plurality of cut films are stacked and rolled, if the temperature is set high, the films will bond together during rolling, resulting in a relatively thick moisture-proof film. In addition, when a plurality of cutting films are stacked one on top of the other and rolled at low temperature, the bonding between the films is weak, so that they can be peeled off after rolling. Even when such a cut film is rolled, the MFR and crystallinity of the film do not change much. However, although the reason is not clear, it has been found that the moisture-proof performance of the film is further improved. Next, an EL element according to another aspect of the present invention will be described. This EL element consists of two electrodes, at least one of which is transparent, facing each other, a light-emitting layer sandwiched between both electrodes, and a PCTFE moisture-proof film covering these, and the MFR of the moisture-proof film.
is 5×10 ^-2 cc/sec or less and crystallinity is 50% or more. A feature of the EL element according to the present invention is that a PCTFE film having specific physical properties is used as a moisture-proof film, and the element structure itself may be the same as that of conventional products. The drawings show examples of the EL device of the present invention. This EL element has a transparent electrode 1 and a back electrode 2 (made of aluminum foil, copper foil, etc.) facing it, a light emitter layer 3 and an insulating layer 4 are sandwiched between these electrodes, and the entire is PCTFE
Moisture-proof film 5,6 (thickness is usually about 50~
300 μm). Note that various modifications are possible, such as making both electrodes transparent or sealing by providing an adhesive layer on a moisture-proof film, if desired. As the transparent electrode 1, on one side of the transparent base material 8,
A transparent conductive layer 7 that is transparent and conductive in the visible light range and has a thickness of usually about 50 to 1000 Å is used. The transparent substrate 8 may be a glass plate or a film or plate made of thermoplastic resin such as polyethylene terephthalate, polycarbonate, polyether sulfone, or polyacrylonitrile, or thermosetting resin such as epoxy resin, polyester resin, or melamine resin. can be used. The transparent conductive layer 7 can be formed on the transparent base material 8 by conventionally known vacuum evaporation methods, sputtering methods,
This can be done by ion plating method or the like. The three layers of the luminescent material emit light when a voltage is applied, and can be formed, for example, from a mixture of a phosphor and a polymeric dielectric material as a binder, and the thickness thereof is usually about approx.
It is 20 to 100 μm. The phosphor is made of a main ingredient such as zinc sulfide, zinc selenide, or a mixed crystal of zinc sulfide and cadmium sulfide, metal powder such as copper, silver, gold, or manganese as an activator, and chlorine, bromine, or activator as an activator. A mixture containing a halogen such as iodine or a metal powder such as aluminum or gallium can be used. In this case, the mixing ratio of the base agent, activator, and activator is
Usually, the amount of the activator is 0.01 to 0.1 part by weight and the activator is 1 to 3 parts by weight per 100 parts by weight of the main agent. Examples of the polymeric dielectric material as a binder include cellulose resins such as cyanoethyl cellulose, fluororesins such as polyvinylidene fluoride and copolymers containing vinylidene fluoride, epoxy resins, unsaturated polyester resins, organosilicon resins, Melamine resin, urea resin, polyurethane resin, etc. can be used. The mixing ratio of the phosphor and polymeric dielectric as components for forming the phosphor layer may vary depending on various conditions, but usually 100 parts by weight of the polymeric dielectric is mixed with the phosphor.
50 to 600 parts by weight. The phosphor layer is made by dissolving polymeric dielectric powder in an organic solvent such as acetone, methyl ethyl ketone, dimethyl formamide, dimethyl acetamide, dimethyl sulfoxide, etc., dispersing phosphor powder in this solution, and dispersing this liquid. It can be formed by coating on a transparent electrode (screen printing, spin coating, etc.) and drying. Further, the insulating layer 4 can be formed of the same polymeric dielectric material as used for forming the light emitting layer (with high dielectric constant powder such as barium titanate or titanium oxide mixed therein if desired). This insulating layer can also be omitted. (Example) Hereinafter, the present invention will be explained in more detail with reference to Examples. Example 1 PCTFE powder with MFR of 1.3×10 ^-3 cc/sec was
℃ and this was maintained at 130℃ with an inner diameter of 300mm
Fill the metal cylinder. And the temperature
The temperature is raised to 250℃, the pressure is maintained at 60Kg/cm ² , and the mixture is heated under pressure for 100 minutes to form a cylindrical block. Next, leave it at room temperature (25°C) and slowly cool it down. At this time, at the start of cooling, the pressure is increased at a rate of 1 Kg/cm ² per minute to reach a pressure of 300 Kg/cm ² , and this pressure is maintained until the end of cooling. After slow cooling, the pressure is returned to normal and the block-shaped body (outer diameter 30 cm, inner diameter 25 cm) is taken out from the cylinder. Next, this block-shaped body is cut with a lathe,
A long PCTFE film (sample 1) with a thickness of 200 μm and a width of 30 cm was obtained. On the other hand, three types of films (Samples 2 to 4) were obtained in the same manner as above except that PCTFE powders having different MFRs were used. Comparative Example 1 The same PCTFE powder used to obtain Samples 1 and 2 was melt-extruded using a T-die extruder, and this was rapidly cooled to form a 200 μm thick film (Sample 5).
and 6) were obtained. The T-die temperature during extrusion was set at 320°C, and the cylinder temperature was set at 260-310°C. Comparative Example 2 The same PCTFE powder used to obtain Samples 3 and 4 was used and the same procedure as Comparative Example 1 was carried out, but the obtained 2
All types of films had streaks and unevenness, and had a poor appearance. Example 2 The PCTFE film of Sample 1 was rolled through a pair of metal rolling rolls (temperature 190°C) to a thickness of 100μ.
A PCTFE film (sample 7) of 500 m was obtained. Example 3 Layer two PCTFE films from document 1,
This was rolled in the same manner as in Example 2 to a thickness of 200 μm.
m (thickness after rolling is 50% of that before rolling)
A PCTFE film (Sample 8) was obtained. Example 4 Three types of PCTFE films (Samples 9 to 11) were obtained in the same manner as in Example 3 except that two PCTFE films of Materials 2, 3, and 4 were used one on top of the other. Table 1 shows the results of measuring the MFR, crystallinity, tensile strength, and water vapor permeability of the PCTFE films obtained in the above Examples and Comparative Examples using the methods described below. In addition, as a mounting test, EL devices were created using these PCTFE films, and the lifetimes of these devices were measured. The results obtained are also listed in Table 1. [MFR] Measurement was performed using an elevated flow tester (manufactured by Shimadzu Corporation) under the conditions of a temperature of 230°C, a load of 100 kg, a nozzle diameter of 1 mm, and a nozzle length of 1 mm. [Crystallinity] Measure the specific gravity (d) of the film and calculate it using the following formula. Crystallinity (%) = d-2.072/2.183-2.072×100 [Tensile strength] Using a universal tensile tester (manufactured by Toyo Baldwin Co., Ltd., Tensilon), the temperature was 25°C, and the tensile speed was 50 mm/
Measured under conditions of min. [Water vapor permeability] Cut the film to 10 cm lengthwise and widthwise, overlap the two films, and heat-seal the edges to a width of 5 mm to form a sealant. Note that 20 g of silica gel is sealed in this sealing body. 50 of this
Leave it in an atmosphere of 95% °C and determine the amount of water vapor permeation by the amount of moisture absorbed by the silica gel. [Mounting test] Reactive magnetron sputtering with an enzyme was performed on one side of a 75 μm thick transparent polyethylene terephthalate film (transparent base material) using an In-Sn alloy with a Sn content of 10% by weight as a target. A transparent conductive layer with a thickness of 200 Å is formed by the method. Thereafter, the phosphor powder was dispersed in an acetone solution of cyanoethyl cellulose as a binder, and this station was applied onto the transparent conductive layer by screen printing, heated at 60°C for 120 minutes, and further heated.
By raising the temperature to 150℃ and heating for 2 minutes,
A phosphor layer with a thickness of 60 μm is formed. As the phosphor powder, a powder containing zinc sulfide as a main component was used, and the blending ratio (weight ratio) of the powder and cyanoethyl cellulose was 84:16. Next, barium titanate powder is dispersed in the same acetone solution of cyanoethylcellulose as described above and applied onto the luminescent layer. The blending ratio (weight ratio) of barium titanate and cyanoethyl cellulose was 1:1. After that, most of the acetone was removed by heating at a temperature of 60℃ for 120 minutes, and a 200μm thick aluminum foil was placed on the luminescent layer. At the same time as forming a layer, an aluminum foil (back electrode) is closely attached on the insulating layer. Next, the PCTFE film was placed on the polyethylene terephthalate film and the aluminum foil, and heated and pressurized for 1 minute at a temperature of 250°C and a pressure of 2 kg/cm ² to thermally fuse the PCTFE films together around the entire edge. Width of fused part 5
mm) to obtain an EL element with the same structure as the drawing. A voltage of 100 V and 50 Hz was applied to each of these 100 EL elements in an atmosphere of 40°C x 95% RH, and the number of elements with a luminance half-life of 200 hrs or more was counted.

[Table] (Effects of the Invention) The present invention has the above-mentioned structure, and is a film with a high degree of crystallinity, which can be suitably used for moisture-proofing purposes. It is possible to easily obtain a strong film with a high degree of oxidation, and furthermore, the EL device of the present invention has the advantage of having a long life.

[Brief explanation of the drawing]

The drawing is a sectional view showing an example of an EL element according to the present invention. 1... Transparent electrode, 2... Back electrode, 3... Luminescent layer, 5, 6... Moisture-proof film.

Claims (1)

[Scope of Claims] 1. A polychlorotrifluoroethylene film having a flow value of 5×10 ^-2 cc/sec or less and a crystallinity of 50% or more. 2. It is characterized by compression molding polychlorotrifluoroethylene to form a block-like body, then gradually cooling this block-like body so that its crystallinity becomes 50% or more, and then cutting it into a film shape. Method for producing polychlorotrifluoroethylene film. 3 Compression molding polychlorotrifluoroethylene to form a block-like body, then slowly cooling this block-like body so that its crystallinity becomes 50% or more, and then cutting it into a film shape, and then cutting the cut film. A method for producing a polychlorotrifluoroethylene film, which comprises rolling a polychlorotrifluoroethylene film. 4. The method for producing a polychlorotrifluoroethylene film according to claim 3, which comprises stacking two or more cut films and rolling them. 5 Consists of two electrodes facing each other, at least one of which is transparent, a luminescent layer sandwiched between the two electrodes, and a moisture-proof film made of polychlorotrifluoroethylene covering these, and the flow value of the moisture-proof film is 5. ×10 ^-2 cc/sec or less and crystallinity is 50%
An electroluminescent element characterized by the above.