JPH08263619A - Information recording medium and its manufacture method - Google Patents

Abstract

PURPOSE: To provide an information recording medium which is provided with the function of a conventional information recording medium and in which the whole card is degraded under a regular condition and to provide the manufacture method by forming a magnetic recording layer showing degradability on a base material taking into consideration of degradability. CONSTITUTION: The degradable magnetic recording layer 3 is formed on the base material having degradability by melting/extruding the mixture of a plastic and a magnetic body, which has degradability. Thus, the magnetic recording layer 3 showing degradability can directly be formed on the base material 2 and can be used as a magnetically recordable information recording medium. When disposing, the whole recording medium can speedily be degraded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording medium having a degradable magnetic recording layer formed on a degradable substrate and a method for producing the same.

[0002]

2. Description of the Related Art At present, cards made of plastic such as synthetic resin are widely used. For example, ID cards for identification, membership cards, cash cards with monetary value, credit cards, prepaid cards, commuter passes, etc. It is used in a wide range of fields such as touring tickets. For example, as the card with the most usage,
A so-called prepaid card (prepayment card) in which a certain amount of money is paid in advance and the value information for that amount is recorded
There is. Value information and identification information are printed or printed on the card base material via a reading / writing device as picture / character information, and the magnetic recording unit or optical recording unit provided on the card base is equipped with a machine. Since it is recorded as read information, mechanical characteristics called gate characteristics, such as durability, bending resistance, and rigidity, are required for use in this reading / writing device. As a material that meets these conditions and is easy to manufacture,
Generally, this prepaid card mainly uses a plastic such as polyethylene terephthalate (PET) resin, that is, a resin satisfying only mechanical characteristics as a card base material.

Further, polyvinyl chloride resin is used as a base material for general cards such as ID cards, membership cards, cash cards and credit cards. These are usually cards that are sold or rented to the user and then discarded when the user finishes using the card. And the plastic card of the above-mentioned material is currently disposed of by incineration or landfill as waste after the treatment after use, but the plastic waste is high heat of combustion temperature due to incineration according to the latter material. It has problems of durability of incinerator due to liquefaction, pollution of combustion gas, etc., and it is impossible to completely separate it from the former material which is less affected by incineration. In the case of landfill as waste, it remains in its original form without being decomposed at the landfill site, and remains semi-permanently as waste, which has a problem of affecting the natural environment. In any case, there is a problem of disposal after use.

Cards using paper as a card substrate have been used in the past. In particular, the paper is easy to incinerate or discard in landfill, and the manufacturing cost is low. It seems to be the best card material for solving environmental problems such as dust. However, when paper is used as the card substrate, durability, bending resistance, water resistance, chemical resistance, waterproofness, surface smoothness, glossiness,
Since the function is inferior in all respects considering the suitability as a card such as processability, the use of paper alone is limited to temporary use such as passage ticket, admission ticket, boarding ticket, and used for a certain period It has been said that it is not suitable for the above-mentioned prepaid card. In this case, polyethylene on the paper substrate,
It is conceivable that an outer layer other than plastic such as synthetic resin such as polypropylene, polyvinyl chloride, polyethylene terephthalate, etc., or aluminum foil may be laminated as a protective layer, but these are not excellent in disposability, and there is a big difference with the above plastic card. Have.

Therefore, Japanese Patent Laid-Open No. 57-150393 / 1982,
JP-A-59-220192, JP-A-51-939
As described in JP-A-91, JP-A-63-260912, and JP-A-57-150393, plastics that can be decomposed in the natural environment such as light or underground have been developed, and especially disposable products. Used for packaging,
Currently, some are commercialized. In the field of cards, JP-A-5-42786 and JP-A-5-85 by the present applicant
No. 088 describes the use of biodegradable or photodegradable plastic for the card substrate.

Further, Japanese Patent Application Laid-Open No. 7-9788 by the present applicant
There is a card having a biodegradable resin layer according to No. 1 on one or both sides of a paper base material, which has characteristics as a conventional plastic card and has excellent disposability.

By the way, a magnetic recording system is mainly used as an information recording means of the above card. In this magnetic recording system, a base material is directly coated with magnetic paint to provide a magnetic recording layer, or a magnetic transfer foil is formed. It was provided by forming the magnetic recording layer by transfer after formation. In addition to magnetic materials, these magnetic paints use a polymer resin (for example, polyurethane resin, nitrocellulose resin, vinyl chloride-vinyl acetate copolymer, polyester resin, etc.) as a binder, a general-purpose solvent (for example, methyl ethyl ketone, acetone, methyl ethyl ketone, and other ketones). , An aromatic hydrocarbon such as toluene or xylene), or a water-dispersible emulsion (eg acrylic emulsion, polyurethane emulsion). Furthermore, the magnetic recording layer of the above card has durability, abrasion resistance, heat resistance,
Physical properties such as chemical resistance and chemical properties are required, and therefore cross-linking agents (such as isocyanates and amines) may be added to the polymer resin.

[0008]

However, the materials used for these magnetic recording layers show almost no decomposability, and since a cross-linking agent is added to the binder, plastics that are not decomposable should be used as a result. If, by any chance, it is left in the environment, there is a problem that the magnetic recording layer remains semipermanently in the current state. Further, since the magnetic recording layer is formed so as to cover at least a part of the card, it is said that the decomposition from the card surface side covered with the magnetic recording layer which is not biodegradable even if the card has degradability is prevented. I have a problem. Further, as a characteristic of the above-mentioned biodegradable or photodegradable plastic, it is almost insoluble in a general-purpose solvent, so that after the processing method is melted, a molding method such as an injection molding method or an extrusion coating method is used. Since it cannot be used as a binder for a magnetic paint constituting a magnetic recording layer, it has not been used as a biodegradable magnetic paint. Therefore, in order to solve the problem that the entire card is not excellent in disposability as described above, the present invention uses a base material in consideration of decomposability and forms a magnetic recording layer exhibiting decomposability so that a conventional information recording medium is formed. It is an object of the present invention to provide an information recording medium having the function of, and in which the entire card is disassembled under normal conditions.

[0009]

The present invention, which has been made to achieve the above object, is characterized in that, in at least one surface of a base material having decomposability, a decomposable plastic and a magnetic material are provided. An information recording medium characterized by forming a magnetic recording layer formed by melt-extruding a mixture of

The invention according to claim 2 is the information recording medium according to claim 1, characterized in that the base material having degradability is paper.

The invention according to claim 3 is the information recording medium according to claim 1, characterized in that the degradable substrate is a biodegradable plastic.

According to a fourth aspect of the present invention, in the information recording medium according to the first aspect, the degradable base material is a composite in which paper and degradable plastic are laminated.

According to a fifth aspect of the present invention, in the information recording medium according to the first aspect, the base material having degradability is a composite in which degradable plastics are laminated on both sides of a paper base material. .

The invention described in claim 6 is the same as in claim 1,
The information recording medium described in 3 is characterized in that the degradable plastic can be decomposed by light or microorganisms.

According to a seventh aspect of the invention, there is provided an information recording medium characterized in that a magnetic recording layer is formed on a base material having decomposability by melt extrusion of a mixture of decomposable plastic and a magnetic material. It is a manufacturing method.

The invention described in claim 8 is the method for manufacturing an information recording medium according to claim 6, characterized in that the degradable plastic can be decomposed by light or microorganisms.

[0017]

According to the information recording medium and the method for producing the same of the present invention, a magnetic recording layer is formed by melt-extruding a mixture of a degradable plastic and a magnetic material on a degradable substrate. The magnetic recording layer exhibiting the property can be directly formed on the base material, and thus it can be used as an information recording medium capable of magnetic recording and the entire information recording medium can be promptly disassembled at the time of disposal.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings. 1 is a sectional view of an information recording medium of the present invention, FIGS. 2 and 3 are sectional views of an information recording medium of another embodiment of the present invention, and FIGS. 4 and 5 are used as comparative examples. It is a sectional view of an information recording medium.

The information recording medium 1 shown in FIG. 1 has a constitution in which a decomposable magnetic recording layer 3 is formed on a substrate 2, and the decomposable substrate used for the substrate 2 is exposed to light or natural environment. Substances that have the property of being able to decompose polymers to oligomers, monomers, and even low-molecular levels by the action of microorganisms such as bacteria, molds, and yeasts that exist in the end, and finally to water, carbon dioxide, methane, etc. Made of paper,
For example, commonly used statistical paper, cardboard, card paper, coated Manila, coated ball, ivory, cardboard, and the like, and any plastic having a decomposability equal to or higher than that of paper, such as a plastic that is decomposed by light, for example, A copolymer of ethylene and carbon monoxide,
There are polyethylene having a ketonic carbonyl group, polystyrene, thermoplastic 1,2-polybutadiene, polyisobutylene oxide, general-purpose plastics to which a photosensitive component is added, and plastics that can be decomposed by microorganisms such as 3-hydroxybutyric acid-3-hydroxyl. A microbial polyester such as a valeric acid copolymer [P (3HB-3HV)], a polycaprolactone (PCL), a chemically synthesized polyester comprising a condensation polymer of glycol and carboxylic acid;
Polyglycolide such as polylactic acid, polyvinyl alcohol / starch, cellulose, chitosan and natural polymers and microbial polysaccharides composed of a complex thereof can be used, and further, a mixture of the above plastics,
Alternatively, a stack of each can be used.

If the weight ratio of the above degradable plastic is 50% or less, various kinds of inorganic fillers such as calcium carbonate, mica, calcium silicate, white carbon, asbestos, porcelain clay (calcined), glass fiber, etc. Non-degradable substances such as additives and polymers may be added. It should be noted that adding more than 50% of a non-decomposable substance causes a problem that the decomposability is remarkably reduced and a problem in processing (punching into a card shape, printability is deteriorated, and laminate strength is reduced). , Not preferable.

The degradable magnetic recording layer 3 uses a degradable plastic as a binder, and the degradable plastic material used for the substrate 2 can be used.
It is preferably a resin suitable for the melt extrusion method, and is a 3-hydroxybutyric acid-3-hydroxyvaleric acid copolymer [P (3HB
-3HV)], polycaprolactone (PCL), chemically synthesized polyester formed by polycondensation of glycol and dicarboxylic acid, polylactic acid, polyvinyl alcohol (PVA).
It is a thermoplastic resin such as a starch complex. Further, for example, γ-Fe ₂ O ₃ , Fe ₃ O ₄ , Co-doped F added to this binder as a magnetic substance for magnetic recording.
There are magnetic iron oxides having a needle-like crystal structure such as e ₂ O ₃ , Co-deposited Fe ₂ O ₃ and CrO ₂ , and the necessary coercive force (for example, 300 to 3000 Oe), average particle diameter, axial ratio (long axis /
A magnetic material can be selected and used from the short axis) and the specific surface area. In addition, silicone oil, higher fatty acids (for example, fatty acids such as stearic acid, palmitic acid, oleic acid, and aliphatic esters such as butyl stearate), lubricants such as molybdenum dioxide, antistatic agents such as carbon black and graphite are required. Can be added according to

In the method of manufacturing the information recording medium of the present invention, the magnetic coating material obtained by mixing the above materials is melt-mixed and pelletized, and then the base material 2 is formed from a known calender roll or T-die.
Then, the decomposable magnetic recording layer 3 is formed by the melt extrusion method. First, a master batch is prepared by dispersing and mixing a magnetic material, additives and the like in a binder, and these are melted to form the degradable magnetic recording layer 3 on the base material 2 by T-die melt lamination processing. As a manufacturing method suitable for the information recording medium of the present invention, a T-die type single layer or a T-die type multilayer extrusion laminating method can be used.

For example, in the multi-layer extrusion laminating method of the T-die method by co-extrusion, it is not necessary to use a solvent, and at the same time as the polyolefin, 3-hydroxybutyric acid / 3-hydroxyvaleric acid having a low processing temperature (150 to 200 ° C.) is used. When co-extruding a linear polyester that is a copolymer of a polymer, the excess heat is absorbed by the polyolefin with a large specific heat, so 3-hydroxybutyric acid
It has the advantage that the linear polyester of the copolymer of 3-hydroxyvaleric acid copolymer does not decompose thermally.

A more specific example will be illustrated and described in detail. <Example 1> A decomposable magnetic coating having the following composition was applied on a base material 2 having a thickness of 200 µm on a paperboard (rolled up) ["Uncoated Ivory" 180 g / m ² ] by a T-die melt extrusion method. Layered to a thickness to form the decomposable magnetic recording layer 3, card size (length 86 mm x width 54 m)
m) to produce the information recording medium 1 shown in FIG. ○ Decomposable magnetic coating composition-Magnetic iron oxide Co-γFe ₂ O ₃ [CTX-970; manufactured by Toda Kogyo Co., Ltd.] 100 parts -Carbon black (# 40; manufactured by Mitsubishi Kasei Co., Ltd.) 3 parts A mixture having the above composition was melted at 200 ° C and then mixed to prepare a masterbatch. This master patch is melted (about 180 ° C.) at the time of producing the decomposable magnetic recording layer to form a magnetic coating material.

The obtained information recording medium 1 is used in the soil (field soil).
Observing the decomposition state periodically (1 to 2 months) after burying in the substrate, the degradable magnetic recording layer 3 was almost completely decomposed after 1 month, and the substrate 2 had a shape It remained in a retained state. After 6 months, the shape of the decomposable magnetic recording layer 3 could not be confirmed, and about half of the base material 2 remained.

<Embodiment 2> The substrate 5 is made of P having a thickness of 200 μm.
A degradable magnetic paint having the same composition as in Example 1 was applied to a sheet of (3HB-3HV) [Biopol (trade name) Hydroxy Yoshigusa content 5%; manufactured by Zeneca] by a T-die melt extrusion method. Layered to a thickness of about 15 μm to form a decomposable magnetic recording layer 6, and a card size (length 86 mm × width 5)
4 mm) to produce the information recording medium 4 shown in FIG.

The obtained information recording medium 4 is put in the soil (field soil).
Observing the decomposed state periodically (1 to 2 months) after burying in the substrate, the decomposable magnetic recording layer 3 is almost completely decomposed after 1 month, and the substrate 5 has a shape It remained in a retained state. After the lapse of 3 months, the shape of the degradable magnetic recording layer 6 could not be confirmed, and the shape of the substrate 4 was not retained, and the material was almost completely decomposed.

<Embodiment 3> Paperboard 9 having a thickness of 200 μm (rolled up) [“uncoated ivory” 180 g / m ² ].
And biodegradable plastic layer 1 of chemically synthesized polyester [Bionole (trade name); Showa High Polymer Co., Ltd.] on both sides
A base material 8 was formed by melt extrusion coating of Nos. 0 and 11 to a thickness of about 30 μm, and a degradable magnetic paint having the same composition as in Example 1 was fused on one of the biodegradable plastic layers by T-die melting. By the extrusion method, the layers were laminated to a thickness of about 15 μm to form a decomposable magnetic recording layer 12 and processed into a card size (length 86 mm × width 54 mm) to manufacture the information recording medium 7 shown in FIG.

The obtained information recording medium 7 is put in the soil (field soil).
As a result of observing the decomposed state periodically (1 to 2 months) after being buried in the base, the decomposable magnetic recording layer 9 is in a state of being almost completely decomposed after 1 month, and the base material 8 has a shape. It remained in a retained state. After 6 months, the shape of the degradable magnetic recording layer 12 could not be confirmed, and about half of the base material 8 remained.

Example 4 Ethylene having a thickness of 200 μm
In the base material 14 of the carbon monoxide copolymer [Knuckle P (trade name); manufactured by Nihon Unicar Co., Ltd.], knuckle P was used instead of P (3HB-3HV) in the composition of the decomposable magnetic paint of Example 1. The decomposable magnetic paint using (trade name) is laminated to a thickness of about 15 μm by the T-die melt extrusion method to form the decomposable magnetic recording layer 15, and the card size (vertical 86 mm ×
It was processed to have a width of 54 mm), and the information recording medium 13 shown in FIG. 4 was produced.

The obtained information recording medium 13 was left standing on the soil surface, and the state of decomposition was observed periodically (at a frequency of 1 to 2 months). After 4 months, the decomposable magnetic recording layer 15 and the substrate 1 were observed.
A large number of cracks were generated in No. 4, and although the shape was maintained, it remained in a brittle state. After 10 months, the shape could not be confirmed.

Next, a comparative example was prepared to clarify the difference from the information recording medium of the present invention. <Comparative Example 1> As shown in FIG.
m paperboard (rewind) ["Uncoated Ivory" 18
0g / m ² ], urethane-based magnetic ink (MAG
3000A; made by Dainichiseika Co., Ltd.) with a wire bar coater #
The magnetic recording layer 18 is coated with 20 to a thickness of about 12 μm and dried.
Was formed and processed into a card size (length 86 mm × width 54 mm) to manufacture an information recording medium 16.

When the obtained information recording medium 16 was buried in soil (field soil) and the decomposition state was observed periodically (frequency of 1 to 2 months), the magnetic recording layer 18 was formed after 6 months had elapsed. The shape of the base material 17 on the surface not held is not retained,
Although only about half of the magnetic recording layer 18 remained, the magnetic recording layer 18 remained in a perfect shape, and slight growth of mold was recognized on the surface thereof.

The information recording media of Examples 1 to 4 are commercially available magnetic card reader / writers (MCP25).
1; Sankyo Seiki Seisakusho Co., Ltd.) was used to record 210 dpi, and magnetic recording and magnetic reproduction were performed.

As described above, it has been difficult to give the magnetic recording layer decomposability even when the degradable plastic is used as the card substrate, and thus the magnetic recording which is not decomposed as shown in Comparative Example 1 is used. Not only is the layer not decomposed by itself, but even if the base material has a decomposable property, the decomposition of the surface side on which the magnetic recording layer is formed is impeded, and the decomposition rate is reduced.

[0036]

As described above, according to the information recording medium and the method for manufacturing the same of the present invention, the magnetic recording layer is formed by melt-extruding the mixture of the decomposable plastic and the magnetic material on the decomposable substrate. By forming the, the degradable magnetic recording layer can be directly molded on the substrate, has the same characteristics as the current card, and can be used under the same conditions of use. In particular, it can be used as an information recording medium capable of magnetic recording, and the entire information recording medium can be promptly disassembled when it is discarded other than by incineration, so the impact on the environment should be reduced. You can

[Brief description of drawings]

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

FIG. 2 is a sectional view of an information recording medium of another embodiment of the present invention.

FIG. 3 is a cross-sectional view of an information recording medium of another embodiment of the present invention.

FIG. 4 is a sectional view of an information recording medium of another embodiment of the present invention.

FIG. 5 is a sectional view of an information recording medium used as a comparative example.

[Explanation of symbols]

 1, 4, 7, 13 Information recording medium 2, 5, 8, 14 Base material 3, 6, 12, 15 Degradable magnetic recording layer 9 Paperboard 10, 11 Biodegradable plastic layer 16 Information recording medium 17 Base material 18 Magnetic Recording layer

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location B42D 15/10 551 B42D 15/10 551A G11B 5/80 G11B 5/80 5/848 7303-5D 5 / 848

Claims (8)

[Claims] 1. An information recording medium comprising a degradable base material and a magnetic recording layer formed on at least one surface thereof by melt extrusion of a mixture of a degradable plastic and a magnetic material. . 2. The information recording medium according to claim 1, wherein the degradable substrate is paper. 3. The information recording medium according to claim 1, wherein the degradable substrate is biodegradable plastic. 4. The information recording medium according to claim 1, wherein the degradable substrate is a composite of paper and degradable plastic. 5. The information recording medium according to claim 1, wherein the degradable substrate is a composite in which degradable plastics are laminated on both sides of a paper substrate. 6. The degradable plastic is degradable by light or microorganisms.
Information recording medium described. 7. A method for producing an information recording medium, which comprises forming a magnetic recording layer on a degradable substrate by melt extrusion of a mixture of degradable plastic and a magnetic material. 8. The method for manufacturing an information recording medium according to claim 7, wherein the degradable plastic can be decomposed by light or microorganisms.