JPH07144468A - Production of magnetic visible card - Google Patents

Abstract

PURPOSE:To suppress a contract change with the elapse of time by disturbance and sharpen visible display by microencapsulating magnetic flakes along with oil to form a microcapsule visible display region and adding water in a specific amt. with respect to initial supplied water at the time of the dispersion of the magnetic flakes. CONSTITUTION:A magnetic visible card 10 consists of a transparent base material 20, a microcapsule layer 30 arranged in order to form a visible display region and a magnetic sheet 40 holding a magnetic recording region. The microcapsule layer 30 contains a large number of microcapsules 32 dispersed in a binder 31 and magnetic flakes 34 received in the microcapsules 32 along with an appropriate oily liquid 33 but, when the magnetic flakes 34 are dispersed, water whose amt. is 3-4.5 time initial supplied water is added after the addition of initial supplied water to stabilize dispersion. The dispersion structure of the magnetic flakes in the microcapsules 32 is set to a multilayered dispersion structure of the magnetic flakes 34. By this constitution, the area of the magnetic flakes is increased to sharpen visible display.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetically visible card capable of magnetically repeatedly recording information and visually displaying the recorded information.

[0002]

2. Description of the Related Art Heretofore, as a magnetic visible card of this type, a microcapsule layer has been formed by attaching microcapsules containing oil and magnetic flakes to the surface of a transparent substrate with a transparent binder. When is oriented parallel to the surface of the transparent substrate, it reflects visible incident light to visually display the bright color of the magnetic flakes,
Also, when the magnetic flakes are oriented perpendicular to the surface of the transparent substrate, visible light is not reflected and the dark color (for example, black) of the magnetic sheet is visually displayed, and the visible display is achieved by the contrast between them. What was done was proposed.

[0003]

However, in the conventional magnetic visible card, the dispersion structure of the magnetic flakes contained in the microcapsules together with the oil is not controlled, and in an extreme case, one microcapsule cannot be used. As shown in Fig. 1, the initial contrast could not be sufficiently secured due to the structure in which one magnetic flake was dispersed in the magnetic flakes, and the magnetic flux was magnetically affected by disturbances such as vibration, magnetic field, and temperature over time. The flakes move, the initial contrast cannot be secured, and as a result, the visible display becomes unclear.

Therefore, in order to eliminate this drawback, the present invention stabilizes the dispersion by adding 3 to 4.5 times as much water as the initial charged water after dispersion of the magnetic flakes, and as a result, the magnetic properties in the microcapsules are reduced. It is intended to provide a magnetically visible card having a multi-layered dispersed structure of flakes.

[0005]

[Means for Solving the Problems] The means for solving the problems provided by the present invention contains magnetic flakes whose orientation direction is changed in response to a magnetic field together with oil, and makes visible incidence depending on the orientation direction. Forming a microcapsule layer by dispersing a plurality of microcapsules in which the light reflection direction changes in a binder disposed on the surface of the transparent substrate,
A method for producing a magnetically visible card, characterized in that, in a magnetically visible card serving as a visible display area, 3 to 4.5 times as much water as the initial charging water is post-added when the magnetic flakes are dispersed.

[0006]

The magnetic visible card according to the present invention contains the magnetic flakes whose orientation direction is changed according to the magnetic field together with the oil, and the plurality of microcapsules whose visible incident light reflection direction is changed according to the orientation direction. Is dispersed in a binder arranged on the surface of the transparent substrate to form a microcapsule layer. Particularly, when dispersing the magnetic flakes, by adding 3 to 4.5 times as much water as the initial charge water, the dispersion is performed. Stabilization, and as a result, the dispersion structure of the magnetic flakes in the microcapsules is a structure in which the magnetic flakes are dispersed in multiple layers, so that the area of the magnetic flakes in the microcapsules in the initial contrast is increased (Fig. 2, (Refer to the plan view), well reflecting the color that the magnetic flakes have,
Since it suppresses the contrast change over time due to disturbance,
It serves to make the visible display clear.

[0007]

EXAMPLES Next, the magnetically visible card according to the present invention will be specifically described with reference to its preferred examples.

FIG. 3 is a partial sectional perspective view showing an embodiment of the magnetically visible card according to the present invention.
A microcapsule layer 30 functioning as a visible display region is arranged on one surface of the transparent substrate 20, and a magnetic sheet 40 is arranged on the surface of the microcapsule layer 30 so as to form a magnetic field for visible display. It shows the state.

FIG. 4 is a partially enlarged cross-sectional view for enlarging and showing a part of the embodiment shown in FIG. 3, particularly when the magnetization direction of the magnetic sheet 40 is parallel to the surface. 3 shows the correlation between the magnetization direction of the magnetic sheet 40 and the orientation direction of the magnetic flakes 34 contained in the microcapsules 32 in the microcapsule layer 30.

FIG. 5 is a partially enlarged sectional view showing a part of the embodiment shown in FIG. 3 in an enlarged manner. In particular, when the magnetization direction of the magnetic sheet 40 is orthogonal to the surface. 3 shows the correlation between the magnetization direction of the magnetic sheet 40 and the orientation direction of the magnetic flakes 34 contained in the microcapsules 32 in the microcapsule layer 30.

FIGS. 6A and 6B are flow charts showing an example of the manufacturing procedure of the embodiment shown in FIG.

(Structure of Embodiment)

First, referring to FIGS. 3 to 5, the structure of an embodiment of the magnetically visible card according to the present invention will be described in detail.

Reference numeral 10 denotes a magnetic visible card according to the present invention, which includes a transparent base material 20 and a microcapsule layer 30 arranged on at least one surface of the transparent base material 20 to form a visible display area. A magnetic sheet 40 which holds the magnetic recording area and is arranged on the surface of the microcapsule layer 30 so as to form a magnetic field for visible display in accordance with the recorded content (that is, the magnetization state) of the magnetic recording area. I have a package.

The transparent substrate 20 is made of a transparent material having an appropriate thickness (for example, a polyethylene terephthalate film (hereinafter referred to as PET)) and functions as a holder for the microcapsule layer 30.

As for the microcapsule layer 30, a plurality of microcapsules 32 dispersed in a binder 31 and a magnetic material contained in each microcapsule 32 together with an appropriate oily liquid 33 (herein referred to as oil; for example, liquid paraffin). And the flakes 34. With respect to the binder 31, the visible incident light L and the visible reflected lights L ′ and L ″ are transmitted, and it is particularly preferable that they are transparent.

The size of the microcapsule 32 is set so that the visible incident light L is sufficiently reflected and can be clearly displayed when the recorded content of the magnetic recording area included in the magnetic sheet 40 is visibly displayed. Is preferably about 30 μm to 100 μm.

As the magnetic flakes 34, a magnetic metal powder containing nickel is adopted. The magnetic flakes 34 may contain magnetic metals such as iron, silicon, molybdenum, aluminum, chromium and cobalt in addition to nickel.

Magnetic flakes 34 are contained in the microcapsules 32.
The reason why the magnetic metal powder containing nickel is dispersed in multiple layers is as follows.
As shown in the plan view of B, the light reflecting surface can be increased to make the color of the magnetic flakes 34 a bright color. In addition, since the number of layers is large and the number of layers is large, movement due to disturbance in the microcapsule 32 is suppressed.

As a result, the magnetic visible card 10 according to the present invention can improve the contrast of the visible display area due to the difference in the orientation direction of the magnetic flakes 34, and is excellent in stability over time, so that the visible display is sharpened. it can.

When the content of nickel in the magnetic metal powder used as the magnetic flakes 34 is particularly 75% by weight or more, it is clear that the contrast in the visible display region is improved even when observed with the naked eye. It can be confirmed and is preferable. The number of layers is preferably 2 to 50.

For the magnetic flakes 34, the visible incident light L
Is preferably reflected, and when the alignment direction is parallel to the surface, it is necessary to significantly increase the amount of visible reflected light L ′ emitted to the outside of the transparent substrate 20,
It is preferably plate-shaped.

The size of the magnetic flakes 34 must be appropriately determined according to the size of the microcapsules 32, but the major axis is 5 to 30 μm, the minor axis is 1 to 10 μm, and the thickness is 0.1 to. 1 μm is usually preferred.

Around the magnetic flakes 34 are magnetic flakes.
If an appropriate surfactant (for example, oleic acid) that does not easily react with 34 and the oil 33 is arranged, it is possible to prevent the magnetic flakes 34 from coagulating with each other, and the magnetic flakes 34 are attached to the wall surface of the microcapsule 32. Since the adhesion can be suppressed, the magnetic flakes 34 are attached to the microcapsules 32.
Can be accommodated in a stable manner, and the contrast of the visible display region associated with the difference in the orientation direction of the magnetic flakes 34 can be improved.

The magnetic sheet 40 is formed in a known manner by arranging a magnetic film (referred to as a magnetic layer) 41 on the surface of an appropriate base material 42 such as a plastic film,
The magnetic recording area is provided in the vicinity of the microcapsule layer 30. Color of magnetic sheet 40 (that is, magnetic layer
41 or the color of the base material 42) is, for example, black so as to secure the contrast of visible display.

(Manufacturing Procedure) Further, with reference to FIGS. 3 to 6B, an example of a manufacturing procedure of an embodiment of the magnetically visible card according to the present invention will be specifically described.

Dispersion of Magnetic Flake 34 A magnetic metal powder (that is, magnetic flake 34) having a proper shape (for example, a plate shape) containing an appropriate amount of nickel prepared by a well-known method is mixed with a suitable surfactant (for example, olein). Disperse (result is called magnetic flake dispersion) in oil (here, liquid paraffin; hereinafter the same) 33 together with acid, and store in a stirrer (for example, ultrasonic stirrer) for a sufficient time. Stir.

Preparation of Microcapsules 32 Water, gelatin and gum arabic are mixed at an appropriate ratio and sufficiently stirred to prepare a gelatin-rubber mixed solution which will be the binder 31 of the microcapsule layer 30. The gelatin-rubber mixed liquid may be prepared, for example, by mixing 150 cc of charging water, 10 g of gelatin (isoelectric point pH 4.5), and 10 g of gum arabic with each other and thoroughly stirring them.

The gelatin rubber mixed solution is heated to an appropriate temperature (40 to 45 ° C.) while continuing the stirring for facilitating the reaction after the stirring is appropriately progressed.

The magnetic flake dispersion is added little by little to the gelatin rubber mixture under stirring and mixed, and the mixture is stirred for an appropriate time to disperse the fine particles of the magnetic flake dispersion.

In this case the dispersion is stirred for 30 to 90 minutes and then
Add water at 40-45 ° C 3.0-4.5 times that of the charged water and stir (result is called intermediate dispersion). The reason for reducing the amount of water to be charged is to reduce the amount ratio of water and oil so that the oil can be dispersed while maintaining an appropriate size during high speed stirring. The amount of magnetic flakes also stochastically enters a large amount in the microcapsules.

While continuing stirring, an aqueous acetic acid solution (for example, 10% by weight) is added dropwise to the intermediate dispersion until pH 4 is reached. This forms a gelatin and gum arabic coacervate film around the particles of the magnetic flake dispersion (substantially liquid paraffin).

For the purpose of coagulating the film of the gelatin and gum arabic coacervate placed around the fine particles of the magnetic flake dispersion (substantially liquid paraffin), an intermediate dispersion of acetic acid was added dropwise. Cool to moderate temperature with stirring.

The gelatin and gum arabic coacervate film formed around the fine particles of the magnetic flake dispersion (substantially liquid paraffin) bound to the deprotonated amino groups in the gelatin is further coagulated. To the purpose-cooled intermediate dispersion, formaldehyde is added in an appropriate amount.

As a result, the microcapsules 32 are dispersed in gelatin and gum arabic (this is called a microcapsule solution). A magnetic flake dispersion liquid (magnetic flake 34 and oil (here, liquid paraffin) 33) is contained in the microcapsule 32.

For the purpose of promoting the elimination of protons from the amino groups of gelatin, an aqueous sodium carbonate solution (for example, 20% by weight) is added to the microcapsule solution at pH 9.5 while continuing stirring.
Drop until

The microcapsule solution is stirred for a sufficient time (for example, 3 to 30 hours),
Settling the microcapsules 34 (hereinafter referred to as settling capsules)
To allow it to stand, leave it for an appropriate time (for example, 0.5 hours). (Note: The capsule of the present invention contains a large amount of magnetic flakes and thus settles)

Removal of Empty Capsules With regard to the microcapsule liquid, after standing, the settled capsules and the empty capsules float above. Remove empty capsules.

Pure water is added to the sedimentation capsule from which the empty capsule has been removed, and the sedimentation capsule is washed (the resultant product is referred to as sedimentation capsule liquid).

With respect to the settled capsule liquid, whether or not the residual amount of empty capsules has become less than or equal to a predetermined value is determined by the residual amount determination process of empty capsules.

With respect to the sedimented capsule liquid, the process of adding pure water or the process of determining the residual amount of empty capsules is repeated until the residual amount of empty capsules falls below a predetermined value, and the empty capsules are removed.

[0042] For disposed sedimentation capsule solution to the transparent substrate 20, the residual amount of the empty capsules is equal to or less than a predetermined value, after the appropriate concentration (concentration of the e.g. microcapsules 50 wt%) was adjusted to be , Polyvinyl alcohol with appropriate concentration (hereinafter referred to as PVA)
A transparent substrate (eg P
ET film) 20 with an appropriate thickness (eg 30
The microcapsule layer 30 is formed by applying the coating solution to a thickness of 200 μm to 200 μm and drying and solidifying.

[0043] On the surface of the microcapsule layer 30 disposed disposed transparent substrate 20 of the magnetic sheet 40, disposed magnetic layer 41 separately created substrate (e.g. PET film) 42 one on the surface of The magnetic sheet 40 according to the present invention is obtained by arranging the magnetic sheet 40 described above in an appropriate manner.

(Operation of Embodiment) Next, the operation of one embodiment of the magnetically visible card according to the present invention will be described in detail with reference to FIGS.

When the magnetization direction in the magnetic recording area of the magnetic sheet 40 changes from the direction parallel to the surface (see FIG. 4) to the orthogonal direction (see FIG. 5), the surface of the magnetic sheet 40 (that is, the magnetic layer 41). The magnetic flakes 34 contained in the microcapsules 32 of the microcapsule layer 30 that had been oriented in the direction parallel to the surface) had an orientation direction perpendicular to the surface of the magnetic sheet 40 (that is, the surface of the magnetic layer 41). Change,
Visible incident light L incident through the transparent base material 20 is transmitted through the transparent base material.
Almost no reflection toward the outside of 20.

Therefore, the visible incident light L is transmitted to the magnetic sheet 40.
And the surface of the magnetic layer 41 that constitutes the magnetic sheet 40 (that is, the microcapsule layer 30).
By being reflected by a surface (hereinafter referred to as one surface) opposite to the surface of the transparent substrate as visible reflected light L ″.
It will be emitted to the outside of 20.

Therefore, at this time, the color of the one surface of the magnetic layer 41 is visually displayed in the visible display area. By the way, on one surface of the magnetic layer 41, a relatively large amount of visible incident light L is absorbed, and a visible light reflected light L ″ is formed as a transparent base material.
The amount emitted to the outside of 20 is small. When the color of the one surface of the magnetic layer 41 is black, the amount of absorption of the visible incident light L increases and the visible reflected light L ″ is substantially not emitted to the outside of the transparent substrate 20.

On the other hand, when the direction of magnetization in the magnetic recording area of the magnetic sheet 40 changes from the direction perpendicular to the surface (see FIG. 5) to the original parallel direction (see FIG. 4), the microcapsule layer 30 contains The orientation of the magnetic flakes 34 contained in the microcapsules 32 changes in a direction parallel to the surface of the magnetic sheet 40, and the visible incident light L incident through the transparent substrate 20 is transmitted through the transparent substrate 20. It will be sufficiently reflected to the outside of. Therefore, at this time, the color of the magnetic flakes 34 is visually displayed in the visible display area.

The magnetic flakes 34 in the microcapsules 32 other than the display portion are always required to be parallel to the surface. However, since the magnetic flakes 34 have a multi-layered dispersion structure, it is difficult to move due to disturbances, etc. The contrast can be secured.

In short, the magnetic visible card according to the present invention
According to 10, microcapsule layer 30 microcapsules
Since the magnetic flakes 34 housed in 32 have a multi-layer dispersion structure, it is possible to sufficiently secure the visible display region and the display portion other than the visible display region initially and with time when the orientation direction of the magnetic flakes 34 changes, and The recorded contents recorded in the magnetic recording area can be clearly displayed.

(Specific Example) In addition, the magnetically visible card according to the present invention will be described more specifically with numerical values and the like.

Example A plate-shaped magnetic metal powder having a nickel content of 100% by weight (that is, 30 g of plate-shaped nickel powder was dispersed in 150 cc of liquid paraffin as an oil together with 6 g of oleic acid as a surfactant). After that, it was housed in an ultrasonic stirrer and stirred for 4 hours to obtain a magnetic flake dispersion liquid.

150 cc of initial charged water was gelatin (isoelectric point pH 4.
5) 10 g and arabic gum 10 g were mixed and stirred, and then heated to 40 ° C. for facilitating the reaction to obtain a gelatin rubber mixed liquid which became the binder 31 of the microcapsule layer 30.

While stirring the gelatin rubber mixed liquid at a stirring speed of 1000 rpm, the magnetic flake dispersion liquid was added little by little, and the stirring was continued for 70 minutes, and then water (40
(° C.) Was further added at 500 cc to obtain an intermediate dispersion of pH 6.0.

The stirring speed was set to 500 rpm, 10% by weight aqueous acetic acid solution was added dropwise to the intermediate dispersion until pH 4 was reached,
Stirring was continued for another 30 minutes at a stirring speed of 500 rpm.

As a result, a coacervate film of gelatin and gum arabic was formed around the fine particles of the magnetic flake dispersion liquid (substantially dodecylbenzene).
After a further 30 minutes, the intermediate dispersion was cooled to 10 ° C., whereby the gelatin and gum arabic coacervate film formed around the fine particles of the magnetic flake dispersion solidified.

The gelatin and gum arabic coacervate film formed around the microparticles of the magnetic flake dispersion (essentially dodecylbenzene) bound to the deprotonated amino groups in the gelatin is further coagulated. For the purpose, formaldehyde was added to the intermediate dispersion liquid cooled to 10 ° C in an appropriate amount to prepare a microcapsule liquid.

While continuing stirring, a 20% by weight aqueous sodium carbonate solution was added dropwise to the microcapsule solution until the pH reached 9.5 for the purpose of promoting the elimination of protons from the amino groups in gelatin, and then for another 24 hours. The stirring was continued for over 24 hours, and the microcapsules were allowed to settle for 24 hours.

First, the upper part including the empty capsule was removed. The settled microcapsules (that is, settled capsules) were taken out, and pure water was added to obtain a settled capsule liquid.

With respect to the sedimented capsule liquid from which the empty capsules were removed, the residual amount of empty capsules was determined in the empty capsule residual amount determination step.

The settled capsule liquid was repeatedly treated by the step of adding pure water or the step of determining the remaining amount of empty capsules until the remaining amount of empty capsules became a predetermined value or less.

The precipitated capsule liquid from which the empty capsules were sufficiently removed was adjusted so that the PVA content was 8% and the microcapsule content concentration was 50% by weight, and then one surface of the PET film (adhesive was It has been applied beforehand) and heated to 80 ° C. and heat-treated for 30 minutes to be dried and solidified to form a microcapsule layer.

Regarding the surface of the microcapsule layer provided on the PET film as a transparent substrate, an adhesive (pre-attached to the other surface of the PET film having a black magnetic layer provided on one surface) After being bonded via a magnetic field, the magnetic visible card was obtained by heating at 120 ° C. for 30 minutes.

In the magnetically visible card, first, the magnetic flakes contained in the microcapsules in the microcapsule layer are magnetized by making the magnetization direction in the magnetic recording area of the magnetic sheet parallel to the surface by an external magnet. The sheet was oriented in a direction parallel to the surface. Brightness index L _p Brightness difference meter at this time (Suga Test Instruments Co., Ltd., SM Color Computer, SM-5, photometric area 0.20 cm ² ).
It was 55.0 when measured by.

In the magnetically visible card, the magnetic flakes contained in the microcapsules in the microcapsule layer are magnetized by making the magnetization direction in the magnetic recording area of the magnetic sheet perpendicular to the surface of the magnetic sheet by an external magnet. Oriented perpendicular to the surface of the sheet. The lightness index L _{v at} this time was 20.0 as measured by the above-mentioned lightness difference meter.

Therefore, the contrast K (= L _p -L _v ) of the magnetically visible card was 35.0. When this magnetically visible card was allowed to stand in a constant temperature bath at 50 ° C. for 31 days, its contrast K was changed to 33.0.

Comparative Example 1 A visible display device having a single dispersion structure of magnetic flakes in microcapsules was prepared and evaluated in the same manner as in the examples. In this case, the initial charging water was 650 cc, and water was not added afterwards.

Comparative Example 2 The initial charge of water was 150 cc, and the post-addition amount of water was 750 cc, which was 5 times as much.
As a result, the strength of the formed microcapsules was too weak to evaluate.

Comparison between Examples and Comparative Examples As is clear from comparison between Examples and Comparative Examples, according to the present invention, the magnetic flakes contained in the microcapsules of the microcapsule layer have a multilayer dispersion structure. Therefore, the color of the magnetic flakes can be sufficiently reflected, and due to the difference in the orientation of the magnetic flakes, the contrast between the visible display area and the area other than the display area can be sufficiently secured in the initial and time periods. The recorded contents recorded in the recording area can be clearly displayed.

(Modification) In the above description, the magnetic sheet 40 is used.
Although only the case where the base material 42 of the above is transparent and the magnetic layer 41 exhibits a dark color has been described, the present invention is not limited to this, and the base material of the magnetic sheet is opaque and has a dark color (for example, It also includes when it is black). In this case, the color of the magnetic layer of the magnetic sheet may be a bright color.

[0071]

As is apparent from the above, the magnetic visible card according to the present invention contains the magnetic flakes whose orientation direction is changed according to the magnetic field together with the oil, and the visible incident light depending on the orientation direction. A magnetic visible card which forms a microcapsule layer by dispersing a plurality of microcapsules whose reflection directions change in a binder arranged on the surface of a transparent substrate, and which is particularly a magnetic flake. At the time of dispersion, 3.0-4.5 times the initial charge of water is added later to stabilize the dispersion, and as a result, the magnetic flake dispersion structure in the microcapsules has a structure in which the magnetic flakes are dispersed in multiple layers. Therefore, the area of the magnetic flakes occupied in the microcapsules in the initial contrast is increased, the color of the magnetic flakes is well reflected, and it is Since suppress a contrast change, the effect capable of sharpening the visual display.

[0072]

[Brief description of drawings]

FIG. 1 shows a conventional dispersed structure of magnetic flakes dispersed in microcapsules.

FIG. 2 shows the inventive dispersed structure of magnetic flakes dispersed in microcapsules.

FIG. 3 is a partial cross-sectional perspective view showing an embodiment of the magnetically visible card according to the present invention.

FIG. 4 is a partially enlarged cross-sectional view showing an enlarged part of the embodiment shown in FIG.

FIG. 5 is a partially enlarged cross-sectional view showing an enlarged part of the embodiment shown in FIG.

6A is a flow chart diagram showing an example of a structural procedure of the embodiment shown in FIG. 3. FIG.

FIG. 6B is a flowchart showing an example of the structure of the embodiment shown in FIG.

[Explanation of symbols] 10 magnetic visible card 20 transparent substrate 30 microcapsule layer 31 binder 32 microcapsule 33 oil 34 magnetic flakes 40 magnetic sheet 41 magnetic layer 42 substrate

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location G11B 5/842 A 7303-5D

Claims (1)

[Claims] 1. A surface of a transparent substrate is provided with a plurality of microcapsules that contain magnetic flakes whose orientation direction is changed according to a magnetic field together with oil, and whose visible incident light reflection direction is changed according to the orientation direction. Disperse the microcapsule layer in the binder that is placed against the magnetic visible card as the visible display area, and add 3 to 4.5 times as much water as the initial charge water when dispersing the magnetic flakes. And a method for manufacturing a magnetically visible card.