JPS5950988B2 - Manufacturing method of magnetic display panel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a display magnetic panel by filling and enclosing a dispersion liquid containing magnetic particles into a recessed part of a substrate in which a recessed part is formed.

When a magnetic force is applied to a display magnetic panel from the front surface using a magnet, the magnetic particles in the dispersion liquid migrate only to the area on the front side of the magnetic panel that receives the magnetic force, creating a display, and the magnet is applied from the rear surface of the magnetic panel. When a magnetic force is applied, the magnetic particles migrate to the rear surface and the display object on the front disappears. Hitherto, it is not clear what method is suitable for automatically manufacturing such magnetic panels.

In the liquid filling/sealing method for items other than magnetic panels, the liquid is filled into a box-shaped container and degassed through a liquid filling process, a defoaming process, and a film bonding process, and then the opening side of the container is covered with a film. It is known to encapsulate liquid by sealing. However, such a method allows air to get mixed in and cannot be used as a manufacturing method for magnetic panels.

In other words, if you create a magnetic panel with air mixed in, it will look clean. In terms of performance, the displayed object becomes blurred, and clear, high-contrast, high-tone displayed objects cannot be obtained.
This causes the display to disappear quickly once it is formed, and furthermore, even if a magnetic force is applied to the opposite side of the display, the display does not disappear completely. The inventor of the present invention has conducted extensive research to develop a method that can fill and encapsulate the dispersion liquid without air being mixed in. As a result, the inventors have found that the mixing of air is prevented by the formation of recesses due to the gaps provided on the surface. Substrate (hereinafter referred to as
It's called a "container."

), they discovered that this is caused by air bubbles generated when the dispersion liquid is filled in the container, and air that gets mixed in when the dispersion liquid is sealed in the container by sealing a film on the container, and completed the present invention. The present invention comprises (8) a step of filling a container with a dispersion liquid containing magnetic particles, and (B) applying the magnetic force of a magnet from the bottom side of the container filled with the dispersion liquid to attract the magnetic particles, causing the magnetic particles to settle. (C) A pressure roller is applied to move the adhesive-coated flexible film from one end to the other end from one end of the opening of the container to the other end. This is a method for manufacturing a magnetic display panel, which includes a step of bonding together.

One of the features of the present invention is that magnetic force is applied from the bottom side of the container when defoaming air bubbles in the filled dispersion liquid.

The present inventor has investigated various devices known as defoaming devices, but depending on the composition of the dispersion liquid, defoaming is uncertain in some devices, and the structure is complicated and expensive.

For this reason, we investigated the possibility of degassing reliably regardless of the composition of the dispersion liquid and found a device with a simple structure. They discovered that defoaming can be achieved by utilizing the presence of particles. In other words, the magnetic particles and air bubbles mixed in the dispersion liquid are forcibly attracted to the bottom of the container by magnetic force, so that the magnetic particles instantly settle, and the air bubbles are instantly pushed upward in their place. It is lifted up and exposed to the outside air to degas it. Therefore, the more viscous the dispersion liquid is to be defoamed, as described below, the more effective it is, and there is no need to determine the transport speed of the container based on the defoaming process time. It has the advantage of being extremely simple in structure and reliable compared to other methods. Another feature of the present invention is that a flexible film coated with an adhesive is pasted from one end to the other end with a pressure roller from one end of the opening of the container filled with the dispersion liquid to the other end. It's about matching.

The present inventor has studied various known film bonding devices, but in the conventional devices, air exists between the liquid surface and the film, and the air cannot be removed.

For this reason, we investigated a film pasting method that could eliminate air and automate the film pasting process.
If you use a pressure roller to attach a flexible film coated with adhesive from one end to the other from one end of the opening of the container to the other end, you can eliminate air between the liquid surface and the film, and keep air inside. This is because we have discovered that it is possible to obtain a magnetic panel in which there is no magnetic field. The magnet used in the present invention can be either a permanent magnet or an electromagnet.

The pressure roller can be made of highly elastic and chemical-resistant materials such as nitrile rubber, urethane rubber, silicone rubber, chloroprene, etc.; however, depending on the composition of the dispersion liquid, materials other than the above, such as PVC, natural rubber, etc. can be used. , other elastic materials can also be used.

Any film can be used as long as it is flexible enough to cover the recessed part of the container, and various plastics such as vinyl chloride, polyester, polyamide, cellophane, polyethylene, polyethylene, paper, synthetic paper, etc. Examples include non-woven fabrics, tin, metal foils such as aluminum, and laminates made by appropriately combining plastics, paper, and metals. Further, if this film is used on the display side of the magnetic panel, a transparent or semi-transparent material is used, and if it is used on the side opposite to the display side, it does not necessarily need to be transparent. As the adhesive to be applied to the film, various adhesives can be used, such as polyester adhesives, cyanoacrylate adhesives, and various other pressure-sensitive adhesives and heat-sensitive adhesives, but epoxy adhesives, Particularly suitable are polyurethane adhesives and vinyl adhesives.

The dispersion liquid used in the present invention can be of various compositions as long as it contains magnetic particles, but if a dispersion liquid with the following viscosity is used, it will be difficult to disperse when it is made into a magnetic panel. It is possible to stably hold magnetic particles with a large specific gravity in a liquid at a specific position, and only when they receive magnetic force above a certain level can the magnetic particles be moved all at once, making it an excellent magnetic display panel. Optimal.

That is, this dispersion liquid is a fine particle thickener selected from fine powder silicic acid, fine powder silicate, fine powder alumina, fine powder calcium carbonate, fine powder magnesium carbonate, or metal soap,
Activators, organic gelling agents, polymer compounds, various greases,
It is a dispersion liquid consisting of vaseline, high concentration emulsion, carbon black, pigment, thickener of finely powdered silica, magnetic particles, colorant, and dispersion medium. In particular, when the yield value of this dispersion liquid is 5 dyne/Cm2 or more, it becomes particularly excellent. In addition, when a fine particle thickener is used as the thickener and the concentration is 5 dyne/Cm or more, a particularly excellent display magnetic panel can be obtained. There are many fine particle thickeners that can be added to the dispersion medium to give it a yield value, but the most suitable ones are anhydrous silicic acid, hydrated silicic acid, and hydrated silicic acid. Calcium, hydrated aluminum silicate, silica powder, diatomaceous earth,
Finely divided silicic acid and finely divided silicates consisting of kaolin, hard clay, soft clay, bentonite, etc. alone or in combination, alumina, extremely fine calcium carbonate, minor calcium carbonate, extremely fine activated calcium carbonate, and heavy carbonate. Calcium, hydrous basic magnesium carbonate, barium sulfate, benzidine yellow, and the like can be used, and these fine particle thickeners can be used alone or in combination.

The term "yield value" here refers to the limit value (minimum value) of stress necessary to apply stress to a liquid and cause the liquid to flow; for example, in the liquid flow curve shown in Figure 1. , is expressed by the stress shown at point A.

The dispersion medium can be either a polar dispersion medium such as water or glycols, or a non-polar dispersion medium such as an organic solvent or oil.

In addition, magnetic particles include, for example, particles of oxide magnetic materials such as black magnetite, γ-hematite, chromium dioxide, and ferrite, and particles of alloy-based metal magnetic materials such as iron, cobalt, and nickel, and granulated particles of these particles. can be used.

Furthermore, the color tone of these particles can be adjusted if necessary. As the size of the magnetic particles becomes smaller, the magnetic force of the display/erasing magnet and the defoaming magnet becomes more difficult to act on. When used as a panel, the magnetic particles become suspended in the dispersion medium, making the magnetic panel appear black and dirty.

Therefore, there is no particular restriction on the size of the magnetic particles, but a particle size of 10 microns or more is most preferable.

Note that even if the particle size of the magnetic particles is 10 microns or less, favorable results are often obtained when the magnetic particles aggregate in the dispersion liquid and have an apparent diameter of 10 microns or more. The magnetic particles are kneaded with a resin solution, dried and then pulverized, or sprayed and dried to bind the magnetic particles together and keep the apparent size of the magnetic particles within a certain range. It is preferable to granulate the particles in a uniform manner because it improves migration properties and clarity of display.

Note that, instead of the resin solution, granulation may be performed using an inorganic material such as gypsum or water glass. The granulated magnetic particles produced in this manner are also referred to as magnetic particles in the present invention. White pigments, yellow pigments, and other dyes or pigments are used to impart hiding properties and color to the dispersion liquid in which the magnetic particles are suspended, thereby increasing the color contrast between the display formed by the magnetic particles and the background. A coloring agent selected from the following is used by adding it to the dispersion liquid.

It is preferable to add 10% or less, preferably 3% or less of a coloring agent to the dispersion liquid, since it is possible to increase the contrast between the dispersion liquid and the magnetic particles, and as a result, the display can be clearly read.

If the amount of colorant is too large, the display by the magnetic particles will become unclear, which is not good. Note that when the fine particle thickener itself has sufficient hiding properties and has a color tone that contrasts with the magnetic particles, there is no need to separately add a coloring agent. The container used in the present invention may be made of transparent or semi-transparent plastic or glass if it is used on the display side of the magnetic panel, and if it is used on the side opposite to the display side, it is not necessary. However, it does not need to be transparent, and metal can also be used.

In the case of plastic or glass, it may be colored or not. The opening part constituting the container may be a separate member from the substrate, or may be integrally molded with the substrate in advance.

Furthermore, it is also possible to provide a flange-like horizontal thick portion bent outward from the upper end of the rear portion in the rear portion to facilitate bonding of the film.

Furthermore, a plurality of recesses formed by the openings can be provided, and in this case, a plurality of panels can be obtained at once by cutting the openings together with the film after filling the dispersion liquid. The container can also be provided with a number of individually partitioned and upwardly open multi-cell structures.

With this configuration, a clear display with extremely high contrast can be obtained compared to a device without a multi-cell structure, and the film also adheres to the multi-cell structure, allowing the dispersion liquid to flow through the film. Since it will be completely sealed in each cell,
It is preferable because it is extremely stable even after being subjected to harsh handling and over a long period of time. Such a multi-cell structure can be made separately or integrally with the substrate. The multi-cell structure separate from the substrate can be made of metal, plastic, paper, resin-treated paper, nonwoven fabric, asbestos, etc., and it is particularly suitable to use a honeycomb core.

The cross-sectional shape of each cell of the multi-cell structure placed in the container may be circular, semicircular, polygonal, or polygonal, but the smaller the area of the cell, the clearer and more continuous the display will be. preferable.

Further, the thinner the partition walls between the cells, the better the continuous display can be obtained, and the thickness is preferably less than 0.5 mm. In addition, the depth of the cell can be changed appropriately depending on the purpose of use, but in order to obtain a clear display with high contrast and to erase clearly, a range of 0.3 to 20 mm is recommended.
In particular, a gap of 0.5 mm to 2.0 mm is optimal. Next, embodiments of the container will be described with reference to the drawings.

The container shown in FIG. 2 has a board 2 fixed around the base 1.

The container shown in FIG. 3 has a multi-cell structure 3 which is individually partitioned and opened upward and is integrally molded with a substrate 4. The container shown in FIG.

The container shown in FIG. 4 has a large number of individually partitioned multi-cell structures 5 that are open at the top and bottom and are fixed to a substrate 1.

The container shown in FIG. 5 has a side part 7 integrally formed around the base plate 6, and a flange-like horizontal thick part 8 bent outward from the top of the side part 7, which is formed by the side part 7. The multi-cell structure portion 5 is arranged in the recessed portion.

The container shown in FIG. 6 has a plurality of concave portions 9, 9, and the upper portions of the adjacent concave portions 10, 10 are connected to a horizontal thick portion 1.
1.

The container shown in FIG. 7 has a plurality of concave portions 12, 12, and adjacent concave portions 12, 12 are partitioned by a partition]3. There are three holes in the recesses 9 and 12 of the container shown in FIGS. 6 and 7.
Of course, the multi-cell structures 3 and 5 described in FIGS. 5 to 5 may be provided. The multi-cell structures 3 and 5 used in the containers shown in FIGS. 3 to 5 are the honeycomb core 1 shown in FIG.
4 or a core 15 having a rectangular cross section as shown in FIG.

Furthermore, a plurality of corrugated plates 16 shown in FIG. 9 may be arranged in a row, and the top portion 17 of each corrugated plate 16 may be fixed to the top portion 17 of the adjacent corrugated plate 16 to form a cap-shaped core 18. Next, examples of the present invention will be shown. Isoparaffin M (trademark of isoparaffin solvent manufactured by Etsuo Chemical Co., USA) 82
1.5 parts of Aerosil 200 (4) (trademark of fine powder silicic acid manufactured by Hon Aerosil Co., Ltd.), and Typeke CR
-50 (trademark of titanium oxide manufactured by Ishihara Sangyo Co., Ltd.) 0.8
The part is T. K. The mixture was kneaded using a homomixer (a wet dispersion machine manufactured by Tokushu Kika Kogyo Co., Ltd.) to produce a white liquid.

On the other hand, 30 parts of Todakara Ichi KN-320 (trademark of magnetite manufactured by Toda Kogyo Co., Ltd.), Polysol SH-502 (
8 parts of vinyl acetate resin emulsion (trademark, manufactured by Showa Kobunshi Co., Ltd.) and 8 parts of water were kneaded, dried and ground to produce 16 parts of black magnetic particles having a mesh size of 100 to 325. Then, the magnetic particles were mixed and dispersed in the white liquid to prepare a dispersion liquid having a yield value of 30.0 dyne/Cm2, and the dispersion liquid was housed in a tank constituting a liquid filling device. Next, the container shown in Fig. 5 (cell size: 4 mm square, multi-cell structure thickness: 1.4 mm) is filled with the above dispersion liquid, and the magnetic force of a permanent magnet is applied from the bottom side of the container to cause the dispersion liquid to flow. The air bubbles were defoamed.

Subsequently, the 0.1 mm vinyl chloride resin sheets coated with epoxy adhesive were pasted together using a pressure roller from one end of the flange on the opening side of the container to the other end, and then high-frequency welding was performed. (Further treatment was performed after heating at 40° C. for 10 hours to obtain a magnetic panel.

The obtained magnetic panels showed no air intrusion at all, and all the magnetic panels sequentially manufactured had stable quality.

The yield value of the dispersion liquid was measured by a direct method using a Bruckfield type BL viscometer (manufactured by Tokyo Keiki Co., Ltd.) as follows.

The rotor of the viscometer was immersed in the dispersion liquid, and only the dispersion liquid was passed around the rotor for 0.2r without rotating the rotor.
p. When the rotor is rotated at a very slow speed of m, the spring of the rotor is also twisted, causing the rotor and the dispersion liquid to rotate together, but when the rotor is twisted to a certain angle, burrs begin to occur between the dispersion liquid and the rotor.

At this time, the torsion angle scale of the rotor is measured, and the yield value is calculated from this torsion angle scale, the torsion constant of the rotor spring, and the shape and area of the rotor. The conversion formula is as follows. Rotor number Yield value NO. l rotor 0.168θ
NO. 2 rotors 0.840θN
O. 3 Rotor 3.360θ However, θ is the measured rotor torsion angle scale.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the relationship between strain rate and stress to explain the yield value of the dispersion liquid used in the present invention, and FIGS. 2 to 7 are cross-sectional views with the intermediate portion omitted showing examples of containers used in the present invention. Figure 8~
FIG. 10 is a plan view showing a part of the multi-cell structure forming the container.

Claims (1)

[Claims] 1. (A) A step of filling a dispersion liquid containing magnetic particles into a substrate in which a concave portion is formed by a groove provided on the surface;
(B) A step of applying the magnetic force of a magnet from the bottom side of the substrate filled with the dispersion liquid in the concave portion to attract the magnetic particles, and causing the air bubbles in the dispersion liquid to rise and defoaming by the sedimentation of the magnetic particles; C) Includes the step of pasting together a flexible film coated with an adhesive from one end to the other end using a pressure roller from one end of the gap of the substrate filled with the dispersion liquid to the other end. A method for manufacturing a magnetic display panel. 2. The method for producing a magnetic display panel according to claim 1, using a dispersion liquid consisting of a thickener, magnetic particles, a colorant, and a dispersion medium as the dispersion liquid. 3. The method of manufacturing a magnetic display panel according to claim 1, wherein the substrate is a substrate having a multi-cell structure in a concave portion, which is partitioned individually and opened upward.