JP2005345829A - Fiber element for display and fiber sheet for display using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fiber element for display to be an element for display utilizing magnetic particles and capable of performing reversible recording, which can be manufactured without using a complicated chemical reaction and a complicated manufacturing step, has excellent durability and does not generate dust and the like and to provide a fiber sheet for display. <P>SOLUTION: In the fiber element for display, at least magnetic particles are packed in a transparent hollow fiber. In the fiber element, the magnetic particles are favorably colored and the magnetic particles, a pigment having a color different from that of the magnetic particles and wax are packed in the transparent hollow fiber. In the fiber element for display, the magnetic particles and the pigment are favorably colored in black and white, respectively. In the fiber element for display, a core fiber having a color different from that of the magnetic particles, the magnetic particles and the wax are packed in the transparent hollow fiber. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a display fiber element that displays an image by heating and applying magnetism, and a display fiber sheet using the same. In particular, the present invention relates to a reversible image display fiber element that can be recorded many times, a display fiber element sheet using the same, and a reversible image display method.

  Conventionally, various recording methods using magnetism have been proposed. For example, a dispersion medium, white pigment, and magnetic particles that are solid at normal temperature such as wax and become liquid when heated are encapsulated in microcapsules, and the microcapsules are formed into a sheet together with a binder. When this sheet is heated, the wax in the microcapsules dissolves and becomes liquid. When magnetism is applied from the sheet surface side in this state, the magnetic particles migrate toward the sheet surface and display the color of the magnetic particles (usually black). To erase the display, heat again and apply magnetism from the opposite side. The magnetic particles migrate to the opposite side of the sheet, and the color of the white pigment is displayed on the sheet display side. Since wax is a solid at room temperature, magnetic particles do not migrate, and as a result, the printed display has good storage stability (see, for example, Patent Document 1).

  However, in the method using microcapsules, it takes time and effort to encapsulate magnetic particles together with wax by performing complicated chemical reactions, and the manufacturing process becomes complicated. Furthermore, in the production of microcapsules, it is necessary to perform a chemical reaction at a temperature equal to or higher than the melting point of the wax, and it is difficult to synthesize microcapsules having a sharp diameter distribution, which makes it difficult to produce a uniform display element. It was. When the size of the microcapsules is not uniform, there is a problem in that the moving distance of the magnetic particles in each microcapsule is different and display defects occur.

  In addition, a method has been proposed in which a sealed space between the top sheet and the back sheet is divided into cells such as a honeycomb structure, and a dispersion liquid containing magnetic particles and white fluid is sealed in each cell. When the recording magnetic member is brought into contact with the surface sheet and moved, the magnetic particles in the dispersion liquid sealed in the cell corresponding to the trajectory are magnetophoresed from the cell bottom to the surface. As a result, display is performed on the transparent surface sheet due to the contrast difference between the white fluid and the magnetic particles (see, for example, Patent Document 2). However, it was difficult to fabricate honeycomb cells and uniformly enclose the magnetic particle-dispersed liquid in each cell, which was problematic.

  As a method that does not use microcapsules or honeycomb cells, a structure in which white wax mixed with magnetic particles (wax in which a white pigment is dispersed) and spacer particles are sandwiched between a transparent cover film and a base film has been proposed ( For example, see Patent Document 3.) As a display method, a thermal head or a current-carrying thermal head is brought into contact with the base film side, and the wax layer is heated and melted by heating a fine spot inside the resistor film by the thermal head or the current-carrying thermal head. Since the magnetic particles can move freely only in the liquefied part, they are moved and displayed in the upper part according to the magnetic field. Next, the printed wax is fixed by cooling the molten wax to room temperature with a cooling head. However, in this system, the thickness of the wax layer changes during repeated heating and cooling of the wax many times, and the thickness is partially reduced or increased. For this reason, there is a drawback that the print quality deteriorates during use.

  In the prior art as described above, the recording method for many times using magnetic particles has a complicated manufacturing method, and there are problems in the number of times of use and durability.

Japanese Examined Patent Publication No. 53-44425 (first page) JP 2000-250075 (first page, FIGS. 1 to 4) Japanese Patent Laid-Open No. 2003-302660 (first page, FIG. 1)

  The object of the present invention is to display a display element using magnetic particles, which can be manufactured without using a complicated chemical reaction or a manufacturing process, and can be recorded many times with excellent durability. It is to provide an element.

The present invention includes the following inventions.
(1) A display fiber element, wherein at least magnetic particles are filled in a transparent hollow fiber.
(2) The display fiber element according to item (1), wherein the magnetic particles are colored.
(3) The display fiber element according to (1) or (2), wherein the transparent hollow fiber is filled with magnetic particles, a pigment having a different color from the magnetic particles, and wax.
(4) The display fiber element according to item (3), wherein the magnetic particles are black and the pigment is white.
(5) The display fiber element according to (1) or (2), wherein transparent hollow fibers are filled with core fibers, magnetic particles, and wax different in color from the magnetic particles.
(6) The display fiber element according to (5), wherein the core fiber is bonded to the inner wall of the transparent hollow fiber.
(7) The display fiber element according to (5) or (6), wherein the magnetic particles are black and the core fiber is white.
(8) The display fiber element according to any one of items (1) to (7), wherein the color tone is changed by moving the magnetic particles by heating and magnetic force.
(9) The inside of the said transparent hollow fiber is divided into small rooms, and the movement of the filling which exists in each room is restrict | limited. For the display of any one of (1) term-(8) term Fiber element.
(10) The material for the transparent hollow fiber is polyester resin, polyolefin resin, acrylic resin, urethane resin, polystyrene resin, ABS resin, fluorine resin, silicone resin, nylon resin, vinyl chloride. The display fiber element according to any one of items (1) to (9), which is at least one selected from a series resin.
(11) The display fiber element according to (3) or (4), which is produced by simultaneously extruding the transparent hollow fiber material, magnetic particles, pigment, and wax from a nozzle.
(12) The display according to any one of (5) to (7), wherein the transparent hollow fiber material, the core fiber material, the magnetic particles, and the wax are simultaneously extruded from a nozzle. Fiber element.
(13) A display fiber sheet, wherein the display fiber elements according to any one of items (1) to (12) are arranged in a sheet form.
(14) The display fiber sheet according to item (13), wherein the display fiber elements are bonded to each other to form a sheet.
(15) The fiber sheet for display according to (13) or (14), which is used in a clean room.

  According to the present invention, the configuration of a display element using magnetic particles is simplified, durability is improved, and there is no complicated process in terms of productivity, and it is easy.

  The present invention will be described in detail below. The present invention is, for example, a configuration in which hollow fibers are filled with a dispersion medium such as wax that is solid at normal temperature and becomes liquid when heated, in which magnetic particles and a pigment having a different color from the magnetic particles are dispersed, or An example is a configuration in which hollow fibers in which fibers of a color different from that of magnetic particles are held are filled with a dispersion medium such as wax that is solid at normal temperature and becomes liquid when heated and in which magnetic particles are dispersed.

  The first invention of the present application will be described. FIG. 1 shows one embodiment of the present invention and does not limit the present invention. It is a figure which shows the preparation methods of the fiber element for a display which filled the dispersion medium which is solid at normal temperature in a hollow fiber, and becomes a liquid when heated, and filled with the mixture which disperse | distributed the magnetic particle and the white pigment. The extrusion nozzle has a nozzle part 1 and a nozzle part 2. The nozzle part 1 is a part that extrudes a dispersion in which magnetic particles and white pigment are dispersed in a dispersion medium that is solid at normal temperature, such as wax, and becomes liquid when heated, and the nozzle part 2 is a material for transparent hollow fibers This is the part to extrude. Using such a nozzle, it is simultaneously extruded while being heated, drawn and drawn to a predetermined diameter, and fiberized.

The second invention of the present application will be described. FIG. 2 shows one embodiment of the present invention and does not limit the present invention. For example, inside a hollow fiber holding a white core fiber inside, a dispersion medium in which magnetic particles are dispersed in a dispersion medium that is solid at normal temperature and becomes liquid when heated is placed inside the hollow fiber inner wall and inside the hollow fiber. It is the figure which showed the preparation methods of the display fiber element with which it filled between core fibers. The extrusion nozzle has a nozzle part 1, a nozzle part 2, and a nozzle part 3. The nozzle portion 1 is a portion that extrudes a dispersion in which magnetic particles are dispersed in a dispersion medium that is solid at normal temperature, such as wax, and becomes liquid upon heating. The nozzle portion 2 is for a core fiber in which a white pigment is dispersed. The nozzle part 3 is a part for extruding the transparent hollow fiber material. Using such a nozzle, it is extruded at the same time while being heated, and is drawn to a predetermined diameter to be fiberized.
Furthermore, as shown in FIG. 3, the core fiber in which the white pigment extruded from the nozzle part 2 is dispersed is preferably bonded to the inner wall of the transparent hollow fiber extruded from the nozzle part 3.
In addition, the transparent hollow fiber having the core fiber may be configured to include a pigment having a color different from that of the magnetic particle together with the magnetic particle and the dispersion medium.

The display / erasing method of the display fiber element of the present invention will be described.
4A to 4C show the display state and the erased state of the first invention. FIG. 4a shows a cross-sectional view of the display fiber element of the first invention. For example, a hollow fiber is filled with wax in which black magnetic particles and a white pigment are dispersed. Since the white pigment and the magnetic particles are uniformly mixed, gray is seen from the display side. FIG. 4 b shows the case where heating is applied from the lower part of the display fiber and magnetism is applied from the display fiber display side. The wax as a dispersion medium is dissolved by heating to become a liquid. When magnetism is applied from the display side in this state, the magnetic particles migrate to the display side by magnetic force. As a result, the display is black. FIG. 4c shows the case where heating and magnetism are applied from the bottom of the display fiber. The wax as the dispersion medium is dissolved by heating to become a liquid, and the magnetic particles migrate from the display fiber display side to the lower part. As a result, the display is white with a white pigment color. As described above, the magnetic particles are localized in the hollow fiber by magnetism and heat, so that an image can be displayed / erased.

  5a to 5c show the display state and erased state of the second invention. FIG. 5a shows a sectional view of the display fiber element of the second invention. A space between the white core fiber existing in the hollow fiber and the inner wall of the hollow fiber is filled with wax in which black magnetic particles are dispersed. Since the black magnetic particles are not localized, when viewed from the display side, the gray color, which is a color mixture of the black magnetic particles and the white fibers inside, is shown. FIG. 5 b shows a case where heating is applied from the lower part of the display fiber and magnetism is applied from the display fiber display side. The wax as a dispersion medium is dissolved by heating to become a liquid. Magnetic particles migrate to the display side by magnetic force. As a result, the display is black. FIG. 5c shows the case where heating and magnetism are applied from the lower part of the display fiber. The wax as the dispersion medium is dissolved by heating to become a liquid, and the magnetic particles migrate from the display fiber display side to the lower part. As a result, the display is white, which is the color of the core fiber. In this way, it is possible to display / erase an image by localizing the magnetic particles in the hollow fiber by magnetism and heat.

  Here, the term hollow fiber is used. In general, the name “fiber” is a name given to a thin and long form having a diameter of several hundred μm or less. However, in the present invention, the diameter of the hollow fiber is not particularly limited. The hollow fiber of the present invention includes a hollow tube having a diameter of 1 to 10 mm and a pipe having a diameter larger than that. The diameter is appropriately selected according to the use, and a diameter of about 10 μm to 500 μm is preferably used for display.

  It is necessary to seal the end of the hollow fiber so that the magnetic particle dispersion contained in the hollow fiber does not leak or foreign matter is not mixed. For sealing, there is a method of dissolving the hollow fiber material by heating, etc., but it is preferable to use laser light in terms of sealing shape and the like. Furthermore, it is also a preferable method to cut fibers with laser light and perform sealing at the same time. The interval between the walls forming the small chamber is preferably about 10 μm to 3 mm.

  When the hollow fiber has a uniform cylindrical shape, the thickness of the wax layer changes during display and erasing by heating and cooling the wax for each print, causing a phase change with the solid / liquid. , Thickness unevenness (diameter unevenness) may occur in the length direction of the display fiber element. In order to prevent this, as shown in FIG. 6, it can be improved by providing a wall in the hollow fiber and dividing the fiber into small rooms. As a method for producing a minute room, it is preferable to emboss the display fiber element or to irradiate the hollow fiber with laser light.

  In order to process the image display fiber element into a sheet shape, for example, an aqueous adhesive, emulsion adhesive, urethane, epoxy, polyester, alkyd, amide, Acrylic adhesive adhesive is applied and bundled into a sheet. Alternatively, the display fiber elements can be brought into contact with each other and heated to heat-seal the fibers to form a sheet.

  By disposing a device that applies magnetism and heat to each part of the display fiber sheet, it is possible to erase and write an image. As a device for applying heat, a thermal head used in an ordinary thermal printer can be used. Magnetism may be installed at a position immediately after heating the thermal head.

The materials that can be used in the present invention will be described.
The dispersion medium that can be used in the present invention is one that is solid at room temperature (in the range of about 10 to 35 ° C.) (indicating a solid phase state) and heated to a temperature that is higher than room temperature (in the range of about 40 to 150 ° C.) As long as it is in a fluid state, it is sufficient. Specifically, petroleum waxes such as paraffin wax and microcrystalline wax, mineral waxes such as montan wax, animal and plant waxes such as beeswax, candelilla wax, carnauba wax, wood wax, polyethylene wax, Fischer-Tropsch wax, etc. Commonly known materials such as synthetic waxes can be used alone or in combination as appropriate.

  The melting point of the dispersion medium is preferably 40 to 130 ° C, more preferably 50 to 100 ° C. If the melting point is lower than 40 ° C., it will be in a fluid state at room temperature and the image may be disturbed. On the other hand, if the melting point is higher than 130 ° C., it cannot be melted by the heat applied by the dispersion medium, and even if melted, the melt viscosity may be too high to move the magnetic powder.

  Examples of magnetic particles that can be used in the present invention include magnetite, ferrite and other iron, cobalt, nickel and other metals exhibiting ferromagnetism, alloys containing these elements, and fine particles of compounds. Although the magnetic substance can be used alone, a mixture of two or more kinds of magnetic substances or a mixture of a magnetic substance and a polymer can be used. The average particle size of the magnetic particles is preferably 0.1 μm or more in consideration of image density and the like. More preferably, it is 0.3-5 micrometers. The magnetic powder may be subjected to a surface hydrophobization treatment such as a silane coupling treatment in order to increase the affinity with a dispersion medium such as wax.

  The magnetic powder composed of the magnetic substance and the polymer is formed by kneading the magnetic powder and the polymer and then pulverizing them, or by polymerization such as emulsion polymerization, suspension polymerization, and dispersion polymerization with a monomer in which the magnetic powder is dispersed. This polymer is preferably crosslinkable.

  The color of ordinary magnetic particles is black or brown. In order to make a visual difference from the magnetic particles, it is preferable to disperse a pigment having a color different from that of the magnetic particles in the dispersion medium. For example, when black magnetic particles are used, a white pigment is more preferably used. Examples of white pigments include titanium oxide (white), silica (white), calcium carbonate (white), zinc white, lead white, talc, calcium silicate, and alumina white. The average particle size of the pigment is preferably from 0.1 to 50 μm, more preferably from 0.3 to 5 μm.

  When white magnetic particles are used, a colored dispersion medium containing a colorant other than white may be used. White magnetic particles can be produced by mixing and kneading black or brown magnetic particles, polymer particles, and a white pigment. Examples of white pigments that can be used include titanium oxide (white), silica (white), calcium carbonate (white), zinc white, lead white, talc, calcium silicate, alumina white and the like. As polymer particles, acrylic, methacrylic, styrene, and nylon particles can be used.

  Production of magnetic particles other than white is also possible by the above method. Instead of white pigments, different colorants are used. Specifically, cadmium yellow, cadmium red, cadmium orange, titanium yellow, bitumen, ultramarine, cobalt blue, cobalt green, cobalt violet, azo, bisazo, triazo, anthraquinone, triphenylmethane, stilbene, Ferrocyan compounds, cobalt oxide compounds, phthalocyanine compounds, isoindolinone compounds, molybdenum compounds, DuPont oil red, Orient oil red, rose bengal, quinoline yellow, chrome yellow, ultramarine blue, aniline blue, malachite green oxalate, etc. it can.

  As the transparent hollow fiber, a fiber having high transparency and excellent laser processing suitability is preferable. Specific hollow fiber materials include polyester resins, polyolefin resins, acrylic resins, urethane resins, polystyrene resins, acrylonitrile-butadiene-styrene copolymers (ABS resins), fluorine resins (for example, (Tetrafluoroethylene resin), silicone resin, nylon resin, and vinyl chloride resin.

As the processing laser used in the present invention, a carbon dioxide laser (CO ₂ laser), an yttrium-aluminum-garnet crystal laser (YAG laser), a semiconductor laser, and the like can be used. CO ₂ lasers are widely used for resin cutting and drilling because they are relatively inexpensive, have high output and are easy to handle. Since the oscillation wavelength is around 10.6 μm and there is almost no permeability to the material, it is suitable for cutting and sealing hollow fibers. Further, the YAG laser has a high light condensing property, can emit a short pulse with a high peak, and has an oscillation wavelength in the vicinity of 1.06 μm. If the output is sufficiently increased, the hollow fibers can be cut and sealed, and the walls in the hollow fibers can be produced.

In addition, a semiconductor laser is an example of a laser that has not been as high as a CO ₂ laser or a YAG laser but has recently been used for processing. In general, elements having a plurality of wavelengths from an oscillation wavelength of about 810 nm to 980 nm are used, and a wavelength suitable for a target material can be selected. If the output is sufficiently increased, the hollow fiber can be cut and sealed. Furthermore, the semiconductor laser has a simple oscillator structure and is easy to maintain.

  The display material of the display fiber element of the present invention is filled in a plastic hollow fiber. In addition, the display fiber element is formed into a sheet by resin adhesive or heat-sealing of hollow fibers. For this reason, there is no generation of dust and other dust, and no dust is generated even when used in a clean room.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples. In the examples, “part” means “part by mass” unless otherwise specified.

Example 1
(1) Production of dispersion for display 2 parts of magnetic particles (manufactured by Toda Kogyo Co., Ltd., average particle diameter of 0.25 μ) and 11.6 parts of titanium dioxide (trade name: JR800, manufactured by Teika Co., Ltd., average particle diameter of 0.27 μm) Then, 85.7 parts of paraffin wax (melting point: 50 to 52 ° C., manufactured by Kanto Chemical Co., Ltd.) and 0.7 parts of a dispersant (trade name: OLOA 1200, manufactured by Chevron) were dispersed by heating.

(2) Production of display fiber element Using a base as shown in FIG. 1, the display dispersion produced in (1) and polyethylene terephthalate (PET), which is a hollow fiber material, have an inner diameter of 200 μm. Extrusion molding was performed to obtain a display fiber element. Both ends of the fiber were melted and sealed by heating. Both ends of the fiber are a semiconductor laser (trade name: UDL-15V, manufactured by Olympus Marketing Co., Ltd.), 0.5 W output / 20 msec irradiation, the inner wall of the tube is melted at intervals of 1.5 mm, and the wall is formed. A small room was made.

(3) Sheeting of display fiber element The display fiber prepared in the above (2) was bonded with an adhesive (trade name: BL-2, manufactured by Sekisui Chemical Co., Ltd.) to prepare a display fiber sheet.
(4) Print evaluation The display fiber sheet produced in the above (3) was evaluated with a test printer (trade name: THPMD, manufactured by Okura Electric Co., Ltd.). For magnetism application, a magnet was attached at a position immediately after the thermal head. Printing was possible with an applied voltage of 25 V and a pulse width of 15 msec. To erase the printed image, the sheet was turned upside down and the same procedure was performed to confirm the image erasure.

Example 2
(1) Production of dispersion for display 2 parts of magnetic particles (manufactured by Toda Kogyo Co., Ltd., average particle size 0.25 μ) and 85.7 parts of paraffin wax (melting point: 50 to 52 ° C., manufactured by Kanto Chemical Co., Ltd.) were heat dispersed. .
(2) Production of display fiber element As a base fiber as shown in FIG. 2, the display dispersion produced in the above (1), PET as a hollow fiber material, and a white fiber material in the hollow fiber Titanium dioxide blended PET was extruded to have an inner diameter of 200 μm to obtain a display fiber element. Both ends of the fiber were melted and sealed by heating. Furthermore, the fiber was heated and embossed at a period of 2 mm to produce a small chamber in the fiber.

(3) Forming the display fiber element into a sheet The display fibers prepared in (2) above are aligned (the alignment of the hollow fiber inner wall and the white fiber bonding portion inside the hollow fiber), and the respective display fibers are in close contact with each other. And subjected to hot pressing to produce a display fiber sheet.
(4) Print evaluation The display fiber sheet produced in the above (3) was evaluated with a test printer (trade name: THPMD, manufactured by Okura Electric Co., Ltd.). For magnetism, a magnet was attached at a position immediately after the thermal head. Printing was possible with an applied voltage of 25 V and a pulse width of 15 msec. To erase the printed image, the sheet was turned upside down and the same procedure was performed to confirm the image erasure.

  According to the present invention, the structure of a display element using magnetic particles is simplified, the durability is improved, and there is no complicated process in terms of productivity, and it is easy. In addition, there is no possibility of dust and other rewrite sheets that can be used in offices and clean rooms.

The manufacturing method example of the fiber element for a display of this invention. The manufacturing method example of the fiber element for a display of this invention. The figure explaining the fiber element for a display of this invention. The figure explaining image writing / erasing of the display fiber element of this invention. The figure explaining image writing / erasing of the display fiber element of this invention. An example of a cross-sectional view in which the inside of the display fiber element is divided into small rooms. The manufacture example which makes the fiber element for a display into a sheet.

Claims (15)

  A display fiber element, wherein at least magnetic particles are filled in a transparent hollow fiber.   The display fiber element according to claim 1, wherein the magnetic particles are colored.   The display fiber element according to claim 1 or 2, wherein the transparent hollow fiber is filled with magnetic particles, a pigment having a color different from that of the magnetic particles, and a wax.   The display fiber element according to claim 3, wherein the magnetic particles are black and the pigment is white.   The display fiber element according to claim 1 or 2, wherein the transparent hollow fibers are filled with core fibers, magnetic particles, and wax having a different color from the magnetic particles.   The display fiber element according to claim 5, wherein the core fiber is bonded to the inner wall of the transparent hollow fiber.   The display fiber element according to claim 5 or 6, wherein the magnetic particles are black and the core fiber is white.   The display fiber element according to any one of claims 1 to 7, wherein the color tone is changed by moving the magnetic particles by heating and magnetic force.   The display fiber element according to any one of claims 1 to 8, wherein the inside of the transparent hollow fiber is divided into small chambers, and movement of a filler existing in each chamber is restricted.   The material for the transparent hollow fiber is polyester resin, polyolefin resin, acrylic resin, urethane resin, polystyrene resin, ABS resin, fluorine resin, silicone resin, nylon resin, vinyl chloride resin. The display fiber element according to claim 1, which is at least one selected.   The display fiber element according to claim 3 or 4, wherein the transparent hollow fiber material, magnetic particles, pigment, and wax are simultaneously extruded from a nozzle.   The display fiber element according to any one of claims 5 to 7, wherein the transparent hollow fiber material, the core fiber material, the magnetic particles, and the wax are simultaneously extruded from a nozzle.   A display fiber sheet, wherein the display fiber elements according to claim 1 are arranged in a sheet form.   The display fiber sheet according to claim 13, wherein the display fiber elements are bonded to each other to form a sheet. The fiber sheet for display according to claim 13 or 14 used in a clean room.

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