JP2981640B2 - Information recording medium - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a novel information recording medium having a magnetic recording layer and a reversible display / recording layer, which can be applied as a magnetic card or a magnetic recording medium having a reversible visible information recording section.

[0002]

2. Description of the Related Art In recent years, a new recording medium having a visible information recording section and a magnetic recording section and capable of reversible recording has been proposed (JP-A-3-180389, JP-A-3-3-189).
No. 30188). It is known that these recording media can increase the amount of information when displaying the contents of a magnetic card by applying to a magnetic card or the like provided with a reversible display / recording means (Japanese Patent Laid-Open No. 3-151294). And JP-A-4-60891. In the recording medium, as a material for recording reversible visible information, a film in which an organic low-molecular compound is dispersed in a polymer binder is generally used, and when heat is applied, the light scattering degree is reversibly reduced. By changing, recording and erasing can be performed. The materials used for these are
JP-A-54-119377 and JP-A-57-8
No. 2087, and the like. Further, recording techniques relating to reversibly changing the degree of light scattering using a polymer liquid crystal include JP-A-62-14114, JP-A-2-2513 and Polymer Commer.
munications, Vol. 24, p364 (1
983), Japan Display, p260 (1
986) and the like.

[0003]

However, in a conventional magnetic recording medium, the display colors of a visible information recording portion for performing display / recording means by reversibly changing the light scattering degree are white and silver. In order to improve the degree of light scattering, an aluminum deposition layer is formed adjacent to the visible information recording layer. For this reason, the mirror-finished aluminum vapor-deposited layer has the advantage of increasing the light scattering property (whiteness) of the recording portion, but the background color is silver and the surrounding scenery is exposed or directly. There has been a problem that the visibility of recorded contents is poor due to reflected light entering the eyes. From the viewpoint of visibility, ideally, contrast that can be clearly distinguished, such as display in white and black, is preferable, but a recording medium provided with such a display recording unit has not been found. Therefore, the present invention has been made in view of the above-described problems in the related art,
It is an object of the present invention to provide a magnetic recording medium having a reversible visible information recording section having excellent visibility.

[0004]

The information recording medium of the present invention has a visible information recording layer, a transparent base layer, and a lower refractive index than the transparent base layer, the light scattering degree of which is reversibly changed by an external stimulus. low refractive index layer, Ri Na and a 5 layer of colored base layer and a magnetic recording layer are sequentially stacked, the visible information recording layer, meso
Gen monomer structural unit and non-mesogenic monomer structural unit
And a cross-linked polymer liquid crystal . Further, another information recording medium of the present invention includes a visible information recording layer whose light scattering degree is reversibly changed by an external stimulus, a first transparent base layer, and a low refractive index lower than the first transparent base layer. refractive index layer, Ri Na and a 5 layer of the second transparent substrate layer and coloring the magnetic recording layer are sequentially stacked, the visible information recording layer, main
Sogen monomer structural units and non-mesogenic monomer structures
Has units, characterized Rukoto consisting crosslinked polymer liquid crystal. Then, the information recording medium may be laminated a protective layer on the record layer.

First, the configuration of the information recording medium of the present invention will be described. The information recording medium of the present invention can take various forms depending on the purpose of use and the like. FIG. 1 shows a configuration example of an information recording medium of the present invention.
(A)-(d) show those aspects. In the figure, 1
Is a visible information recording layer, 2 is a transparent substrate layer, 2a is a first transparent substrate layer, 2b is a second transparent substrate layer, 3 is a low refractive index layer, 4 is a colored substrate layer, and 5 is a magnetic recording layer. , 6 are colored magnetic recording layers, and 7 is a protective layer. FIG. 1A shows a visible information recording layer 1 whose light scattering degree is reversibly changed by an external stimulus.
A transparent base layer 2, a low refractive index layer 3 having a lower refractive index than the transparent base layer 2, a colored base layer 4, and a magnetic recording layer 5;
It is configured by sequentially stacking layers. FIG.
(B) is a visible information recording layer 1 whose light scattering degree is reversibly changed by an external stimulus, and a first transparent base layer 2.
a, which is formed by sequentially laminating five layers including a low refractive index layer 3 having a lower refractive index than the first transparent base material layer 2a, a second transparent base material layer 2b, and a colored magnetic recording layer 6. is there. 1 (c) and 1 (d) correspond to FIG.
In the configuration shown in FIG. 1A and FIG. 1B, a protective layer 7 is laminated on the visible information recording layer 1.

Next, each layer constituting the information recording medium of the present invention will be described. The visible information recording layer 1 constituting the information recording medium of the present invention, in which the degree of light scattering is reversibly changed by an external stimulus, is capable of reversibly recording and erasing visible information, and is a mesogenic monomer.
-Having a structural unit and a non-mesogenic monomer structural unit,
What consists of a crosslinked polymer liquid crystal is used. this
Material, Ru der those capable degree of light scattering is reversibly changed by applying heat or the like from the outside, repeated white turbid state and a transparent state alternately, respectively.

[0007]

[0008]

[0009]

In the present invention, a phase-separated polymer liquid crystal obtained by copolymerizing a mesogenic monomer and a non-mesogenic monomer and having a non-mesogenic component in the side chain is crosslinked.
Uses cross-linked polymer liquid crystal obtained by
Is done. In that case, a crosslinked polymer liquid crystal having a multi-domain structure is particularly preferable. By cross-linking the polymer liquid crystal as a multi-domain structure composed of an aggregate of domains of a specific size having optical anisotropy, it is possible to obtain a liquid crystal capable of realizing high-speed and stable recording and erasing. Multi-domain structure means optical anisotropy (birefringence)
A structure composed of an aggregate of a plurality of minute domains having a, is a structure that strongly scatters light. In particular, the multi-domain structure is preferable since the light is most strongly scattered when the diameter of the domain is in the range of 0.2 to 1.5 μm at the maximum of the number of distribution of the domain.

The cross-linking of the polymer liquid crystal can be performed by forming the polymer liquid crystal as a recording layer and then cross-linking by external stimulus such as heat, light, electron beam or the like. In the present invention, examples of the polymer liquid crystal used for crosslinking include a compound containing a reactive group as one component of a main chain or a side chain. In these compounds, crosslinking can be carried out by utilizing a reactive group and adding a catalyst and a polyfunctional reactive compound as required. Specific examples of the reactive group include a vinyl group, an acrylate group, a methacrylate group, an addition or polymerizable group such as a heterocyclic group such as an epoxy group and an isocyanate group, a hydroxyl group, an amino group, an acid amide group, a thiol group, and a carboxyl group. Groups, sulfonic acid groups, phosphoric acid groups, metal alcoholate groups, magnesium halide groups (Grignard reagent) and the like are preferred. As the catalyst, various ultraviolet polymerization initiators, thermal polymerization initiators, etc., as the polyfunctional reactive compound, a polyfunctional isocyanate compound, a polyfunctional epoxy compound, a polyfunctional melamine compound, a polyfunctional aldehyde compound, a polyfunctional amine compound, Polyfunctional carboxyl compounds are preferably used.

The crosslinked side chain type polymer liquid crystal is
Usually, polymerizable mesogenic monomers are converted to non- mesogenic monomers.
Ru can be produced by over copolymerized. Is a top <br/> polymerizable Mesogenmonoma over that describes, biphenyl based, phenyl benzoate based, cyclohexylbenzene based, azoxybenzene based, azobenzene, azomethine, phenyl pyrimidine, diphenyl acetylene, biphenyl benzoate type , Rigid molecules such as cyclohexylbiphenyl and terphenyl (mesogen)
In addition, various compounds having an acrylate, methacrylate or vinyl group bonded thereto, preferably via an alkyl spacer having a predetermined length, may be mentioned as typical examples.

Representative structural examples of these compounds are shown below. These are typical examples of the structure, and the present invention is not limited thereto. CH ₂ ＣC (R ^a ) -COO- (CH ₂ ) _l -OA CH ₂ ＣC (R ^a ) -COO-A CH ₂ ＣＨCH- (CH ₂ ) _l -OA (wherein Ra represents ^a hydrogen or methyl group, l represents an integer selected from 1 to 30, and A represents the following (a) to (k)
2 represents a mesogen group selected from )

Embedded image (Wherein X and Y are each a single bond, -N = N-,
-N (→ O) = N-, -CH = N-, -N = CH-,-
Selected from COO-, -C (C = O)-and ethynylene groups
R ¹ represents an alkoxy group, a halogen atom,
Selected from cyano, carboxyl and alkyl groups
And p represents an integer selected from 1 to 5
However, when p is 2 or more, each R ¹ is different
You may. ) Further, in the fabrication of liquid crystal polymer of the present invention, is a non-Mesogenmonoma over to copolymerization together with the above mesogenic monomers, to be a useful compound in the optimization of improved and thermal properties of the contrast of the recorded image Preferably, for example, alkyl (meth) acrylate and its derivatives, styrene and its derivatives, vinyl acetate, (meth) acrylonitrile, vinyl chloride, vinylidene chloride,
(Meth) acrylic acid, ω-carboxy-polycaprolactone-mono (meth) acrylate, vinyl sulfonate, hydroxyethyl which is a compound having a reactive group for crosslinking, such as vinylpyrrolidone, 1-hexene, 1-octene, etc. (Meth) acrylate, hydroxypropyl (meth) acrylate, 2- (meth) acryloxyethyl acid phosphate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 2- (meth)
Acryloxyethyl succinate, phthalic acid mono (meth) acrylate, 2- (meth) acryloxyethyl (2-hydroxyethyl) phthalate, 4- (meth) acryloxyalkyloxy-benzoic acid, glyceryl (meth) acrylate, Hydroxy-substituted styrene, (meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, glycidyl (meth) acrylate, 2-propen-1-ol, 5-hexene -1-ol or the like may elevation up Rukoto, but is not limited thereto. The compounds described above in the engaged mesogen monomer and copolymerizing the 0.1-70 as monomer units
It is preferable to use it in the range of mol%.

[0014] The polymer liquid crystal crosslinking, using a motor <br/> Noma chromatography as described above, radical polymerization, Ru can be manufacturing by co <br/> polymerization reaction that by the ion polymerization . The weight average molecular weight of the high molecular liquid crystal is preferably in the range of 1,000～100 ten thousand, in particular from 10,000 to 500,000 range is preferred. Further, the shape condition of the copolymer can take random, block, graft, alternating and the like. Further, various components can be added to the visible information recording layer of the present invention for the purpose of improving various characteristics of the polymer liquid crystal. For example, various antioxidants such as hindered amine and hindered phenol may be added for the purpose of improving weather resistance, and for improving the recording contrast, anthraquinone-based, styryl-based, azomethine-based and azo-based ones may be added. And other various dichroic dyes. Various fluorescent dyes may be added for the purpose of improving light scattering. Furthermore, when recording is performed using laser light, various laser light absorbing dyes (780 to 830) are used.
In the case of using a general semiconductor laser of nm, it is preferable to add a near-infrared absorbing dye such as phthalocyanine, squarylium, or azulium). It is preferable that the above-mentioned various components are added to the composition containing the polymer liquid crystal in the range of 0.01 to 5% by weight in the composition. Furthermore, 1 to 20% by weight of the low-molecular liquid crystal compound
Can be added within the range.

The principle of a phase change type recording / erasing method using heat control on the information recording medium of the present invention will be described.
The recording layer of the information recording medium having a polymer liquid crystal initially has an optically anisotropic multi-domain structure and thus exhibits a light scattering (white turbidity) state. When recording on this information recording medium, the polymer liquid crystal is converted into an isotropic (transparent) state by partial heating using a thermal head or laser light,
Thereafter, when the material is rapidly cooled, the heated portion is fixed in a glass state while being isotropic, and the recording portion becomes transparent. On the other hand, when this is erased, it can be erased by returning to the initial light scattering state by cooling after heating and slowly cooling compared to the time of recording. By repeating the above operation, recording / erasing can be realized reversibly many times. When a thermal head is used as such a recording / erasing heating means, for example, it can be achieved by controlling the pulse width and energy applied to the thermal head. Conversely, the recording layer can be set to be in a transparent state at the initial stage and the recording can be performed in a cloudy state. In addition, this record /
The erasing method can also be implemented by using an electric field or a magnetic field. The visible information recording layer of the present invention can be formed by coating with a solvent, and the thickness thereof is selected from the range of 0.1 to 50 μm, and preferably 1 to 20 μm.

Next, the transparent base layer 2 and the first transparent base layer 2a constituting the information recording medium of the present invention are made of a material having a higher refractive index than the low refractive index layer 3,
For example, use a resin film represented by polyester resin, polyether resin, polyurethane resin, polyamide resin, acrylic resin, polyimide resin, polyethylene resin, polypropylene resin, polyvinyl chloride resin, polyvinylidene chloride resin, polycarbonate resin, etc. Is preferred. The thickness of the transparent substrate layer is 1 to 500 μm
Is selected from the range, preferably 10 to 200 μm
Range. The low refractive index layer 3 is made of a material having a smaller refractive index than the transparent base material layer 2 or the first transparent base material layer 2a, and includes a resin layer such as a fluororesin, a gas layer, and a vacuum layer. It is preferred to use In particular, a gas layer and a vacuum layer having a large refractive index difference from the transparent base material layer or the first transparent base material layer 2a are preferable. As the gas layer, an air layer is preferably used. When a gas layer or a vacuum layer is selected as the low refractive index layer, the colored base layer 4 or the second transparent base layer 2b and the transparent base layer or the first transparent base layer 2a are made of resin fine particles or the like. By bonding using an adhesive spacer material or the like, or by partially bonding both substrate surfaces in the presence of gas or under vacuum, a gas layer or a vacuum layer is formed between both substrate surfaces, Further, it can be formed by fixing the colored base material layer or the second transparent base material layer to the transparent base material layer or the first transparent base material layer. On the other hand, when a resin having a low refractive index, such as a fluororesin, is used as the low refractive index layer 3, the low refractive index layer 3 is formed by applying a solvent, or by pressing a film of the resin. be able to. The difference in refractive index between the low refractive index layer and the transparent substrate layer or the first transparent substrate layer is preferably 0.1 or more, more preferably 0.2 or more. Also, the thickness of the low refractive index layer,
It is preferably from 0.01 to 100 μm, particularly preferably from 0.1 to 100 μm.
It is preferably from 1 to 10 μm.

Further, as the colored base material layer 4, resins containing various dyes can be used. Examples of the dye that can be used include carbon black, various pigments, dyes, and the like.The resin includes a polyester resin, a polyether resin, a polyurethane resin, a polyamide resin,
Examples include acrylic resin, polyimide resin, polyethylene resin, polypropylene resin, polyvinyl chloride resin, polyvinylidene chloride resin, and polycarbonate resin. Further, as the color of the dye, various colors can be selected, and as the coloring base material, the above dye may be kneaded, or a resin containing the dye may be coated on a base material such as a film. May be available. The thickness of the colored substrate 4 is preferably 1 to 500 μm, and particularly preferably 10 to 500 μm.
It is preferably from 200 to 200 μm. As the second transparent base material layer 2b, the same material as the first transparent base material layer 2a is used. The two layers may be of the same material or different.

As the magnetic recording layer 5 and the colored magnetic recording layer 6 of the present invention, various magnetic materials dispersed in a resin can be used. BaO-6Fe ₂ O ₃ ,
Fe ₃ O ₄ , γ-Fe ₂ O ₃ , Co-γ-Fe ₂ O ₃ ,
Cr ₂ O _{3 and the} like. As the resin, a thermoplastic resin such as a vinyl chloride-vinyl acetate resin, a polyester resin, a urethane resin, an acrylic resin, an epoxy resin, or a thermosetting resin is used. For the colored magnetic recording layer, a colored magnetic material or a material prepared by adding various dyes or colored additives is used. In particular, a strongly colored magnetic material such as Co-γ-Fe ₂ O ₃ or Cr ₂ O ₃ is preferably used because it is not necessary to add a dye or the like. The use of the colored magnetic recording layer is preferable in that the second transparent base material layer can be used for the adjacent base material, and it is not necessary to use the relatively expensive colored base material 4. Various additives such as various abrasives and waxes can be added to the magnetic recording layer. Further, a protective layer or a printing layer may be provided on the surface of the magnetic recording layer. Also, the protective layer 7
Is laminated in order to prevent surface deterioration of the visible information recording layer 1 by repeatedly performing recording and erasing, and the material is preferably a material having high heat resistance.
A fluorine resin, a silicone resin, a thermosetting resin, an ultraviolet curable resin, an electron beam curable resin, or the like can be used. A plurality of protective layers may be laminated, and the thickness of the protective layer is preferably selected from the range of 0.1 to 20 μm.

[0019]

Since the information recording medium of the present invention has the above-mentioned structure, it can perform visible recording with excellent visibility and contrast. Hereinafter, this case will be described. FIG.
FIG. 4 is a diagram for explaining a process of performing visible recording on the information recording medium of the present invention by changing the degree of light scattering, and is a schematic cross-sectional view. FIG. 2A shows the state of incident light when the recording layer in the light scattering state is irradiated with light. In general, some components of incident light are scattered and emitted (backscattered) by the recording layer, and other components are transmitted through the recording layer. When all components of the incident light are back-scattered, the opacity of the recording layer increases, and recording with high contrast can be performed, which is ideal. However, it is extremely difficult to eliminate all components that penetrate the recording layer due to limitations on the thickness of the recording layer. When light is incident from a medium with a high refractive index to a medium with a low refractive index,
Light has the property of being reflected when the incident angle increases. Since the light transmitted through the recording layer is refracted by the recording layer, if a low-refractive-index layer is formed on the back surface of the substrate on which the recording layer is formed, the transmitted light is transmitted to the low-refractive-index layer at a large incident angle. Since the light is incident, the light is reflected at the interface and scattered again at the recording layer, so that a high light scattering property can be obtained. If the colored layer is formed without providing the low refractive index layer, the components that pass through the recording layer are absorbed by the colored layer, so that the turbidity of the recording layer is significantly reduced. FIG.
(B) shows the state of incident light when the transparent recording layer is irradiated with light. Most of the incident light passes through the recording layer, and the transmitted light has a small incident angle and is absorbed by the coloring layer without being reflected by the low-refractive-index layer, so that a clear color can be expressed. In the present invention, recording is performed by changing the degree of light scattering, and a base material on which a reversible visible recording layer is formed is laminated with a magnetic recording layer or a colored magnetic recording layer using a base material colored via a low refractive index layer. The low refractive index layer functions as a light reflection layer, thereby greatly improving the visibility of the visible recording layer. Furthermore,
When a colored magnetic recording layer is used, the use of a colored substrate or the like can be omitted.

[0020]

EXAMPLES The present invention will be described below in more detail with reference to examples, but the present invention is not limited to these examples. Example 1 (Formation of magnetic recording layer) Magnetic substance: 25 parts by weight of γ-Fe ₂ O ₃ Binder: vinyl chloride-vinyl acetate-vinyl alcohol copolymer (trade name: VAGH, manufactured by UCC) 5 parts by weight Coronate L 1 part by weight (manufactured by Nippon Polyurethane) 1 part by weight Solvent: 30 parts by weight methyl ethyl ketone 30 parts by weight Toluene 30 parts by weight After mixing and dispersing the above substances, a wire bar was placed on a 75 μm-thick black polyethylene terephthalate (PET) film (PET mixed with carbon black). And dried to form a magnetic recording layer having a thickness of about 10 μm. (Formation of visible information recording layer) As a mesogen monomer, 4
1.9 g of acryloxyhexyloxy-4'-cyano-biphenyl and 0.1 g of 2-hydroxyethyl acrylate as a non-mesogenic monomer having a reactive group
With azobisisobutyronitrile (A) as a polymerization initiator
IBN) 0.01 g, methyl ethyl ketone 5 as a solvent
The polymerization was carried out using ml. The obtained polymer solution was purified by repeatedly precipitating three times using ethyl alcohol as a precipitating solvent, and purified to obtain a polymer liquid crystal 1.9 represented by the following structural formula (1).
g was obtained.

[0021]

Embedded image When the obtained polymer liquid crystal was measured, the weight average molecular weight (in terms of polystyrene by GPC) was 80,0.
Tg (glass transition point) was 40 ° C., and Ti (liquid crystal phase-isotropic transition point) was 110 ° C. A solution obtained by adding 0.03 g of 4,4'-diphenylmethane diisocyanate as a cross-linking agent and 3.0 g of methyl ethyl ketone (MEK) as a solvent to 1.0 g of the polymer liquid crystal was used to form a film having a film thickness of 75%.
A clear PET film (refractive index = 1.575) was coated on a μm transparent PET film using a blade coater and dried to form a polymer liquid crystal layer having a thickness of about 7 μm, and then reacted in an oven at 50 ° C. for 24 hours. And allowed to crosslink. The polymer liquid crystal layer after the preparation was scattered light and became cloudy. Further, an ultraviolet curable composition (Aronix UV, manufactured by Toa Gosei Co., Ltd.) was applied and cured using a high-pressure mercury lamp to form a protective layer of about 2 μm on the crosslinked polymer liquid crystal layer. (Preparation of information recording medium) On the other surface of the magnetic recording layer of the film on which the magnetic recording layer was formed, a surface obtained by dispersing an adhesive resin spacer having a diameter of 10 μm was formed. The information recording medium in which the air layer was formed as a low-refractive-index layer (refractive index = 1.0) was produced by bonding the two surfaces together by thermocompression bonding using a heat roller.

Example 2 (Formation of Magnetic Recording Layer) Magnetic substance: 25 parts by weight of Co-γ-Fe ₂ O ₃ Binder: vinyl chloride-vinyl acetate-vinyl alcohol copolymer (trade name: VAGH, manufactured by UCC) 5 parts by weight Coronate L (manufactured by Nippon Polyurethane) 1 part by weight Solvent: methyl ethyl ketone 30 parts by weight Toluene 30 parts by weight After mixing and dispersing the above substances, the mixture was coated on a 75 μm-thick transparent PET film using a wire bar. By drying, a magnetic recording layer having a thickness of about 10 μm was formed. (Formation of Visible Information Recording Layer) The film on which the magnetic recording layer was formed was cut into 10 cm squares, and a film ribbon (width 2 m) for hot-melt bonding was formed on the magnetic recording layer and the other four corners.
m), and the four corners of the film (10 cm square) formed with the polymer liquid crystal layer used in Example 1 were bonded by thermocompression bonding at the four corners. An information recording medium serving as a refractive index layer was produced.

(Recording and Evaluation on Reversible Visible Information Recording Layer) With respect to the visible information recording layer of the information recording medium produced in Examples 1 and 2, its recording characteristics and recorded images were evaluated. A clear black image is recorded on this information recording medium with a resolution of 8 dots / mm and a sensitivity of about 0.3 mj / dot using a thermal head type thermal recording evaluation device. Was completed. Also, this image could be erased by passing it through a heat roller (120 ° C. heating setting). The reflection optical density (reflectance) of the recorded image is X-write9.
68 (manufactured by X-rite). Table 1 shows the results. The image contrast was excellent, and the visibility was excellent because of the black and white display.

[0024]

[Table 1]

[0025]

The information recording medium of the present invention is a mesogenic
Monomer units and non-mesogenic monomer units
Then, by adopting a laminated structure in which a low refractive index layer is interposed between the visible information recording layer composed of cross-linked polymer liquid crystal and the magnetic recording layer using a colored substrate or the colored magnetic recording layer, It can provide a high image contrast and can be applied to a wide range of fields since it has both a reversible visible information recording section and a magnetic recording section with excellent visibility.

[Brief description of the drawings]

FIG. 1 is a sectional view of a configuration example showing an information recording medium of the present invention.

FIG. 2 is a diagram of an information recording medium for describing a process of performing visible recording on the information recording medium of the present invention by changing the degree of light scattering.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Visible information recording layer, 2 ... Transparent base material layer, 2a ... First transparent base material layer, 2b ... Second transparent base material layer, 3 ... Low refractive index layer, 4 ...
Colored base material layer, 5: magnetic recording layer, 6: colored magnetic recording layer, 7
... Protective layer.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takashi Uematsu 1600 Takematsu, Minamiashigara-shi, Kanagawa Prefecture Inside Fuji Xerox Co., Ltd. (56) References JP-A-1-167819 (JP, A) JP-A-3-130188 ( JP, A) JP-A-6-313880 (JP, A) JP-A-62-95516 (JP, A) JP-A-4-218024 (JP, A) JP-A-6-308472 (JP, A) (58) ) Surveyed field (Int.Cl. ⁶ , DB name) G02F 1/1333 G02F 1/1335 G02F 1/13 500 G02F 1/13 505 G09F 9/00-9/46 B41M 5/26 C09K 19/02 C09K 19 / 38-19/40

Claims (4)

(57) [Claims] 1. A visible information recording layer whose light scattering degree is reversibly changed by an external stimulus, a transparent substrate layer, a low refractive index layer having a lower refractive index than the transparent substrate layer, a colored substrate layer, and magnetic recording. Ri Na by sequentially laminating the five layers comprising a layer, the visible information recording layer
Is a mesogenic monomer structural unit and a non-mesogenic monomer
-An information recording medium having a structural unit and comprising a crosslinked polymer liquid crystal . 2. A visible information recording layer whose light scattering degree is reversibly changed by an external stimulus, a first transparent base material layer, a low refractive index layer having a lower refractive index than the first transparent base material layer, and a second transparent base material. Ri Na by sequentially laminating the five layers consisting of a substrate layer and coloring the magnetic recording layer,
The visible information recording layer has a mesogen monomer structural unit and
Crosslinked polymer having non-mesogenic monomer structural units
An information recording medium comprising a liquid crystal . 3. The information recording medium according to claim 1, wherein a protective layer is laminated on the visible information recording layer. 4. The information recording medium according to claim 1, wherein the low refractive index layer is a gas layer.