JP2001075510A - Microcapsule magnetic display sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable production without danger on work, to enable sufficient use even at a low temperature or in a low-temperature area and to substantially eliminate the influence of magnetism even at a high temperature or in a high- temperature area. SOLUTION: This microcapsule magnetic recording sheet has a solid dispersion layer consisting of a dispersion of microcapsules containing a binder, a dispersion and flaky magnetic particulates on a transparent film. In such a case, the boiling point of the solvent constituting the dispersion is >=150 deg.C and the melting point thereof is <=-20 deg.C and the dispersion contains a particulate thickening agent. The microcapsule magnetic recording sheet consists of only the self-supporting layer of the solid dispersion layer or has a colored layer on the surface of either thereof, or has the colored layer on the solid dispersion layer surface on the side opposite to the side having the transparent film of the solid dispersion layer. Also, the colored layer consists of black ink.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microcapsule magnetic display sheet, and more particularly to an excellent microcapsule magnetic display sheet that can be used even at a low temperature.

[0002]

2. Description of the Related Art Conventionally, a microcapsule magnetic display sheet has been known, and is usually used for information transmission after being visually recorded or erased by handwriting, magnetic or the like. Specifically, two types of microcapsule magnetic display sheets are known, one of which is a microcapsule in which a spherical magnetic powder and a colorant (for example, titanium dioxide pigment or the like) are encapsulated. There is a microcapsule magnetic display sheet dispersed in a binder and applied on a substrate or formed into a film. On the other hand, as the magnetic powder, a magnetic powder formed not in a spherical shape but in a flat or flake (flake) is used. Particles were also used to form microcapsule magnetic display sheets (JP-A-55-29880, JP-A-2-146082, and JP-A-50-16004).
No. 6).

[0003] The manufacturing method of these microcapsule magnetic display sheets is common to both, and usually, a microcapsule magnetic display sheet is formed on a substrate.
A dispersion liquid, magnetic fine particles dispersed therein, and a microcapsule containing a coloring agent are further coated and coated with a binder, and a transparent protective layer is provided thereon if necessary. Or by applying this to one side of a magnetic recording card.

In particular, recently, with the spread of magnetic recording cards such as cash cards and prepaid cards having an information storage section, these cards may have a recording display section in order to visually check the recorded contents of these cards. As a result, a technique of combining the magnetic recording card and the microcapsule magnetic display sheet has been developed. As the microcapsule magnetic display sheet used in the recording display section of the magnetic recording card, there are the above two types of microcapsule magnetic recording sheets. Among them, the one using flake-like magnetic powder is described in Japanese Patent Publication No. 7-70039.
And JP-A-5-16579, which have the advantage that particle size distribution, film strength, and industrial production are possible by adding a thermoplastic resin to the microcapsules used.

[0005]

However, a magnetic recording card (hereinafter, referred to as a message card) having such a magnetic display unit can be used in various places, but in a region where the temperature is low, especially in a low temperature area, the magnetic recording card is used. Since the contents contain a thermoplastic resin, there is a problem that the movement of the magnetic fine particles and the like becomes extremely slow at a low temperature of 0 ° C. or lower, and the use becomes impossible. In addition, even the weak magnetism emitted from personal belongings is susceptible to magnetism. Therefore, for example, when a mobile phone, a pocket-size radio, a portable CD, MD, a ticket, or the like is brought close to a message card, the magnetic card may be damaged. There has been a problem that the display portion of the message card is periodically contaminated by the generated magnetism and the display cannot be determined. Furthermore, when mixing a thermoplastic resin and a solvent, it is necessary to heat to 150 ° C. or higher, but since the solvent used is petroleum that is strictly prohibited from fire according to the Fire Service Law, heating is very dangerous. There is a work problem.

Accordingly, the present invention and the like have made various investigations and investigations on these points, and as a result, have found that the present invention can be solved by using a precipitation preventive agent. Thus, the present invention has been made. Therefore, a first problem to be solved by the present invention is to provide a message card that can be used sufficiently even in low-temperature or low-temperature areas. A second object of the present invention is to provide a microcapsule magnetic recording sheet that is hardly affected by magnetism at high temperatures. A third object of the present invention is to provide a microcapsule magnetic recording sheet which can be manufactured without any danger in operation.

[0007]

The above object of the present invention is achieved by each of the inventions described in the following claims.

(1) A microcapsule magnetic recording sheet having, on a transparent film, a solid dispersion layer comprising a binder, a dispersion and a dispersion of microcapsules containing flake-like magnetic fine particles, the dispersion comprising A microcapsule magnetic recording sheet comprising: a solvent having a boiling point of 150 ° C. or higher, a melting point of −20 ° C. or lower, and a fine particle thickener. [2] A microcapsule magnetic recording sheet according to [1], which comprises only a solid dispersion layer. [3] The microcapsule magnetic recording sheet according to [1], further comprising a colored layer on the surface of the solid dispersion layer opposite to the side of the solid dispersion layer having the transparent film. [4] The microcapsule magnetic recording sheet according to [2], wherein a colored layer is provided on any surface of the sheet comprising only the solid dispersion layer. [5] The microcapsule magnetic recording sheet according to [3] or [4], wherein the colored layer is made of black ink.

The microcapsule magnetic recording sheet of the present invention has no danger in operation because the solvent constituting the dispersion has a boiling point of 150 ° C. or more and a melting point of -20 ° C. or less and contains a fine particle thickener. The microcapsule magnetic recording sheet that can be manufactured, and is used for various purposes, can be used without trouble even in low to low temperature regions, and is excellent in that it is hardly affected by magnetism even at high temperature. It is effective. In addition, when used for a magnetic card, there is an excellent effect that the contents of the magnetic recording card can be visually checked. Here, the self-supporting layer of the solid dispersion layer means a layer composed of only the solid dispersion layer and having no other layer such as a transparent film or a black coloring layer on the surface thereof.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in more detail, but the present invention is not limited thereto.

The microcapsule magnetic recording sheet of the present invention is an improved microcapsule magnetic recording sheet using a microcapsule containing a dispersion and flake-shaped magnetic fine particles, and the solvent constituting the dispersion has a boiling point of 150.
Those having a melting point of -20 ° C or higher and -20 ° C or higher are used.
Specifically, as the solvent, 2-octanol (boiling point: 178 ° C., melting point: −38 ° C.), 3-heptanol (boiling point: 1
56.2 ° C., melting point −70 ° C.), 1-hexanol (boiling point 157.1 ° C., melting point −44.6 ° C.), 3-heptanol (boiling point 156.2 ° C., melting point −70 ° C.), 2-ethyl-1
-Hexanol (boiling point 184.7 ° C, melting point -70 ° C),
Mesitylene (boiling point 164.7 ° C, melting point -44.7 ° C),
Butylbenzene (boiling point 169-183 ° C, melting point -58-
-88 ° C), p-cymene (boiling point 177.1 ° C, melting point -6)
7.9 ° C), diethylbenzene (boiling point 181.1 ° C, melting point -83.9 ° C), pentylbenzene (boiling point 205.4)
° C, melting point -75 ° C), dipentylbenzene (boiling point 255
° C, melting point -75 ° C), benzyl acetate (boiling point 213.5)
° C, melting point -51.5 ° C), isopenter butyrate (boiling point 18
4.8 ° C, melting point -73.2 ° C), propyl benzoate (boiling point 231.2 ° C, melting point -51.6 ° C), ethyl benzoate (boiling point 213.2 ° C, melting point -34.6 ° C), benzoic Butyl acid (boiling point 250.3 ° C, melting point -22.4 ° C), bis (adipate) (boiling point 210 ° C, melting point -65 ° C), dibutyl maleate (boiling point 280 ° C, melting point -80 ° C), dibutyl phthalate (boiling point 339 ° C, melting point -35 ° C), bisphthalic acid (boiling point 386 ° C, melting point -55 ° C), dioctyl phthalate (boiling point 284 ° C, melting point -25 ° C), phenylxylylethane (boiling point 290-305 ° C, melting point- 50 ° C.). Particularly preferred among these are 2-octanol, butylbenzene, pentylbenzene, dipentylbenzene, benzyl acetate, propyl benzoate, butyl benzoate, dibutyl maleate, dibutyl phthalate, bis-phthalate, dioctyl phthalate and phenyl Xylylethane. These solvents may be used alone or as a mixture of two or more.

The fine particle thickeners used in the present invention include silicic anhydride, hydrous silicic acid, silicates (sodium silicate, potassium silicate, aluminum silicate, calcium silicate, etc.),
Fine powder alumina, silica powder, diatomaceous earth, karyon, hard clay, soft clay, bentonite, ultra fine calcium carbonate, ultra fine activated calcium carbonate, calcium bicarbonate, hydrous basic magnesium carbonate, barium sulfate, benzidine yellow, etc. No. These may be used alone or as a mixture of two or more. The addition amount of the fine particle thickener depends on the type of the dispersion medium, but is 0.2 to 5% by weight, preferably 0.1% by weight, based on the dispersion medium.
It is 4% by weight to 2% by weight. If the addition amount of the fine particle thickener is less than 0.2% by weight, a sufficient dispersion system cannot be maintained, the magnetic powder is not moved with time, which is not preferable. If it exceeds weight%,
It hinders the movement of solid particles such as magnetic powder.

The flake-like magnetic powder used in the present invention comprises:
What is usually used in this technical field may be used, and examples thereof include fine particles of an alloy or the like appropriately mixed with nickel, iron, chromium, aluminum, samarium, or the like, which are formed into a flake (flake shape). Of these, alloys such as iron / nickel, iron / nickel / chromium and iron / silicon / chromium are preferred. These may be used as a mixture of two or more.

In the present invention, a method for producing microcapsules is well known in this technical field, and it is usually preferable to use a coacervation method (for example, US Pat.
P-2800458). At this time, it is preferable to disperse the components to be included in the microcapsules with a dispersant. The obtained microcapsules are coated on a substrate together with a binder and coated by other means to form a microcapsule dispersion coating layer, dried to obtain a solid dispersion layer, and further a black (or another color, (For example, red, green, brown, blue, etc.), and a protective layer may be provided as necessary. Further, in the present invention, the embodiment of the microcapsule magnetic display sheet can use a self-support composed of a solid dispersion layer, that is, a sheet composed of only the solid dispersion layer, or record one side of the solid dispersion layer. A transparent layer (for example, a transparent film or the like) is provided on the display surface, and a black coloring layer or another colored coloring layer is applied to the other surface. The coloring layer such as the black coloring layer may be coated with a black ink or another colored coloring ink, or may be attached with a synthetic resin film containing these inks.

The microcapsule magnetic recording sheet obtained in this way can be used as a display for writing and erasing characters and pictures repeatedly using a magnetic pen as it is. It can also be used as a message card which can be provided on at least the surface of a magnetic recording card such as a prepaid card and which can perform a magnetic display. As a recording method,
For example, commercially available Star Precision MCP200ZD, MCP
Recording / erasing can be performed by a reader / writer such as 390TD. Further, the microcapsule magnetic display sheet of the present invention,
It can be used for other purposes, for example, for recording harmful electromagnetic waves.

[0016]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

Example 1 The following materials (1), (2) and (3) were sufficiently stirred and mixed to prepare a liquid A.

(1) Flake-shaped magnetic fine particles 20.0 g (Fe / Ni alloy Fe: Ni = 22: 78 Saturation magnetization Ms = 4.9 emu Residual magnetization Mr = 2.2 emu Retention force Hc = 1.4 Oe Average particle size 16 μm Specific gravity 6.1) (2) Finely divided silica (fine particle thickener, trade name, Aerosil 972; manufactured by Nippon Aerosil Co., Ltd.) 1.0 g (3) Bisphthalate 79.0 g

On the other hand, 200 g of a 5% gelatin aqueous solution and 5%
Prepare 200g of gum arabic, mix these,
Was set to 5.5. 100 g of Solution A was gradually added to the obtained solution, and the mixture was stirred and emulsified with a homomixer until the average particle size became 80 μm. Then, the emulsion was cooled slowly, and when the temperature reached 15 ° C., 5 g of a 25% glutaraldehyde aqueous solution was added thereto, followed by stirring all day and night to obtain a microcapsule slurry containing flake-shaped magnetic fine particles.

The obtained microcapsule slurry solution was separated by a 150 μ mesh filter,
The following microcapsules were obtained. Next, the microcapsules were filtered to form a capsule cake, and an aqueous urethane resin solution as an aqueous binder was added thereto, followed by sufficient stirring to obtain an ink composition for coating.

The above ink composition was applied to 75 μm PET by a knife coater method so as to have a thickness of 250 μm, placed in a dryer maintained at 60 ° C., and dried for 1 hour.
A microcapsule-coated sheet was obtained. Further, after black ink was screen-printed on the capsule layer of this sheet, it was adhered to a predetermined place of the cash card with a double-sided adhesive tape to produce a message card (a card with a microcapsule magnetic display sheet). This card has a reader / writer MC
When printing was performed with P200ZD (manufactured by Star Seimitsu Co., Ltd.) in an environment of −10 ° C., clear characters could be obtained. Even if a ticket, a commuter pass or the like having a magnetic recording barcode applied to the back of the message card was attached to the message card, the characters could be sufficiently read without being affected by magnetism.

COMPARATIVE EXAMPLE As a fine particle thickener, 1.0 g of the finely divided silica described in the above example was mixed with an alicyclic saturated hydrocarbon resin (thermoplastic resin, trade name: Alcon P-100, Arakawa Chemical Industry Co., Ltd.) Bis 7 phthalate instead of 10 g
A card with a magnetic sheet was obtained by the method described in Example 1 except that 9 g was replaced with 70 g. When this was printed with a reader / writer MCP200ZD in an environment of −10 ° C. in the same manner as in the example, no printed characters appeared. Also, in this case, the solution must be heated to 150 ° C. to make the solution a solution, which is very dangerous. Then, when a conventional message card was attached to a ticket, a commuter pass or the like having a barcode for magnetic recording applied to the back of the conventional message card, the characters were difficult to read so as to be indistinguishable.

Example 2 Instead of the PET film (transparent film) described in Example 1, the coating ink composition described in Example 1 was applied to the surface of a film having a release agent in the same manner as in Example 1. And dried to obtain a microcapsule magnetic display sheet. Using this sheet formed into an endless belt, letters were recorded on the surface of the sheet under a -10 ° C environment without contact with a magnetic pen. A clear record was obtained. Further, the microcapsule magnetic display sheet was prepared by applying a black ink to the back surface and recording was performed under the above conditions. As a result, clearer characters with larger contrast were obtained. In this message card,
Even if a ticket or a commuter pass having a barcode for magnetic recording applied to the back was attached, the characters could be read sufficiently without being affected by magnetism.

[0024]

The microcapsule magnetic recording sheet of the present invention has a hazardous point on operation because the solvent constituting the dispersion has a boiling point of 150 ° C. or more and a melting point of -20 ° C. or less and contains a precipitation inhibitor. The microcapsule magnetic recording sheet thus produced has an excellent effect that it can be used without any problem even with weak magnetism generated from personal belongings carried daily. Further, the microcapsule magnetic recording sheet of the present invention has an excellent effect that the content of the magnetic card can be visually observed by using the magnetic recording sheet.

Claims (5)

[Claims] 1. A microcapsule magnetic recording sheet having a solid dispersion layer comprising a binder, a dispersion and a dispersion of microcapsules containing flake-like magnetic fine particles on a transparent film, wherein a solvent constituting the dispersion is used. A microcapsule magnetic display sheet having a boiling point of 150 ° C. or higher, a melting point of −20 ° C. or lower, and containing a fine particle thickener. 2. A microcapsule magnetic display sheet according to claim 1, wherein the microcapsule magnetic display sheet comprises only a solid dispersion layer. 3. The microcapsule magnetic display sheet according to claim 1, further comprising a colored layer on the surface of the solid dispersion layer opposite to the side of the solid dispersion layer having the transparent film. 4. The microcapsule magnetic display sheet according to claim 2, wherein a colored layer is provided on any surface of the sheet comprising only the solid dispersion layer. 5. The microcapsule magnetic display sheet according to claim 3, wherein the colored layer comprises a black ink.