JPH10135024A - Image-recording medium and image-forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily form individual magnetic information for each image recording medium by providing, on a supporting body, a layer of a resin comprising, as component, a magnetic substance and anionic functional group-contained monomer as polymerization component. SOLUTION: As magnetic substance, γ-Fe2 O3 , etc., can be named, and as an anionic functional group-contained monomer for a layer, elution removal- property magnetic layer, of the resin comprising the anionic functional group- contained monomer as polymerization component, such monomer as carboxylic acid, etc., are recommended. In addition, as carboxylic acid group-contained monomer, malice acid monster, etc., are used. On a supporting body 5, non- elution removal property magnetic layer 4 containing a magnetic substance is provided, and over it, a magnetic image-information comprising an elution removal property magnetic layer 3 containing magnetic substance is provided. A resist image is formed on the elution removal property magnetic layer, and a non-resist image part is elution-removed, then a card information recording medium having a magnetic image part is eventually formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a means for forming magnetically recognizable image information (or magnetic image).

[0002]

2. Description of the Related Art Magnetic recording systems are used in a wide range of industrial fields today. The main advantages of this magnetic recording method are that information can be rewritten, reading and writing can be performed at high speed, and unlike optical information, the surface is resistant to contamination. Although the magnetic recording method is widely used as described above, it is not without its problems. For example, in a field where an information recording medium such as a magnetic card is used, illegal use thereof may be a problem. This can be said to be an example in which the advantage of the magnetic recording system that magnetic information can be rewritten has turned into a disadvantage. On the other hand, bills and the like are printed using ink containing a part of magnetic material, and confidential information is magnetically recorded. In this case, the specific image information has magnetic information and is used on the assumption that the information is not rewritten. Such a method of using magnetic information as non-rewritable information is very useful for the purpose of providing information for identification on an information recording medium in view of the advantages of the magnetic recording method described above. Until now, such magnetic information has been mainly obtained by forming a magnetic image by printing.

[0003]

The printing method described in the above-mentioned conventional operation is excellent when a large number of image recording media having the same information are manufactured. It is not suitable for providing different information. However, if an attempt is made to use non-rewritable magnetic information formed as an image for security,
Having different information for each image recording medium greatly improves the security. Therefore, means for forming individual information at low cost while taking advantage of the magnetic recording method has been desired.
Accordingly, an object of the present invention is to provide a means for overcoming the drawbacks in forming magnetic information by the above printing method and forming different magnetic information for each image recording medium. In the present invention, a name called an image recording medium is used in order to intend that the held information has image characteristics. The image recording medium described in the present invention is synonymous with an information recording medium in general.

[0004]

In order to solve the above-mentioned problems, the present invention provides a resin (B) comprising at least a magnetic material (A) and an anionic functional group-containing monomer as polymerizable components on a support. ), A resist image is formed on an image recording medium provided with an elution-removable magnetic layer, and then a non-resist image portion is elution-removed to form a magnetically recognizable image. Is provided. In this method, any on-demand printing method such as an electrophotographic method, an inkjet method, and a thermal transfer method can be used as a method for forming a resist image.
It is possible to easily form separate magnetic information for each information recording medium.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The core technique of the present invention is to form a resist image on a magnetic layer containing a resin which can be removed by elution, and then to elute and remove a non-resist image portion. Are as follows.

The support used in the present invention is PE
Synthetic resin films such as T, paper, various nonwoven fabrics, synthetic paper, metal plates, foam films, synthetic resin laminated paper, glass, etc., or composite sheets combining these can be used according to the purpose, but are not limited thereto. It is not something to be done.

As the magnetic material (A) used in the elution-removable magnetic layer of the image recording medium of the present invention, a magnetic material used in a known magnetic recording material can be used. For example, specific examples of magnetic materials include γ-Fe ₂ O ₃ and F
e ₃ O ₄ , Co-containing iron oxide, CrO ₂ , metal powder, Ba ferrite and the like.

In the resin (B) containing the anionic functional group-containing monomer according to the present invention as a polymerization component, the anionic functional group-containing monomer includes a carboxylic acid group, an acid amide group, an amide group and a phenolic group. Examples include monomers having a hydroxyl group, a sulfonic acid group, a sulfonimide group, a sulfonamide group, a phosphonic acid group, and the like. Among them, as the carboxylic acid group-containing monomer, maleic acid monoester, acrylic acid, methacrylic acid, crotonic acid, itaconic acid, benzoic acid, fumaric acid and the like can be used. Examples of the monomer having a phenolic hydroxyl group include phenol and vinyl phenol.

As other polymerization components of the resin (B) containing the anionic functional group-containing monomer according to the present invention as a polymerization component, the elution-removable magnetic layer has improved film forming properties, film strength, and dispersibility of magnetic particles. In addition, a vinyl-polymerizable monomer may be contained depending on the purpose of improving adhesiveness and the like. Examples of the vinyl polymerizable monomer include styrene, α-methylstyrene, O-methylstyrene, m-methylstyrene,
p-methylstyrene, O-methoxystyrene, p-methoxystyrene, m-dimethylaminostyrene, styrene such as p-dimethylaminostyrene and derivatives thereof, vinyl toluene, acrylonitrile, acryloyl morpholine, vinyl chloride, vinyl formate, vinyl acetate, Vinyl propionate, vinyl n-butyrate, vinyl caproate, vinyl caprylate, vinyl caprate, vinyl laurate,
Organic acid vinyl esters such as vinyl benzoate, vinyl palmitate and vinyl stearate, methyl (meth) acrylate, n-butyl (meth) acrylate, n-propyl (meth) acrylate, and isopropyl (meth) acrylate;
Isobutyl (meth) acrylate, t (meth) acrylate
-Butyl, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, 2-dimethylaminoethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, (meth) Examples include (meth) acrylates such as 2-hydroxypropyl acrylate, 2,4-dinitrophenyl (meth) acrylate, and benzyl (meth) acrylate, vinylpyrrolidone, and maleic anhydride.

The weight average molecular weight of the resin containing the anionic functional group-containing monomer according to the present invention as a polymerization component is 50.
00 to 200,000, more preferably 100
00 to 100,000. Weight average molecular weight of 5000
If the amount is less than the above, the mechanical strength of the elution-removable magnetic layer is inferior.

In the elution-removable magnetic layer, in addition to the resin (B) containing an anionic functional group-containing monomer as a polymerization component,
Other resins can be contained as required, such as adjustment of the rheology of the coating liquid, adjustment of the film strength, improvement of the dispersibility of the magnetic particles, and improvement of the adhesiveness. In this case, usable resins include polyurethane resin such as urethane / acrylic copolymer, epoxy resin, phenol resin, phenoxy resin, melamine resin, urea resin, furfural resin, unsaturated polyester resin, alkyd resin, silicon resin, xylene Resin, toluene resin, acrylate / vinylidene chloride copolymer, methacrylate / vinylidene chloride copolymer, methacrylate / styrene copolymer, methyl methacrylate / butadiene copolymer, maleic acid modified acrylic resin, etc. Acrylic resin, styrene / butadiene copolymer, styrene / butadiene copolymer, styrene / butadiene / methyl methacrylate copolymer, styrene / maleic acid copolymer, styrene / acrylic copolymer, styrene / butadiene / methyl methyl copolymer Acrylate copolymers, such as styrene resins, fluorine resins, polyamide resins, polyether resins, polyester resins, polyolefin resins, polycarbonate resins, polyvinyl acetal resins, polyvinyl ether resins, polyvinyl butyral resins, vinylidene chloride / acrylonitrile copolymers, etc. Vinylidene chloride resin, vinyl chloride / vinyl acetate copolymer, vinyl chloride / vinyl acetate / maleic acid copolymer, vinyl chloride / vinylidene chloride copolymer, vinyl chloride / vinyl acetate / vinyl alcohol acid copolymer, vinyl chloride Acrylonitrile copolymer, vinyl chloride resin such as partially saponified vinyl chloride / vinyl acetate copolymer resin, vinyl acetate, melamine / formaldehyde copolymer resin, polyvinyl fluoride resin, butadiene / acrylonitrile copolymer, urea Le formaldehyde resins, cellulose acetate resins, cellulose diacetate resins, triacetate resins, cellulose acetate propionate resins, cellulose resins, hydroxymethyl cellulose resin, hydroxyethyl cellulose resin, carboxymethyl cellulose resin,
Known resins such as a polyvinyl alcohol resin can be used, but the present invention is not limited thereto. However, in order to obtain good elution and removal properties of the magnetic layer, the ratio of the other resin component to the resin (B) containing an anionic functional group-containing monomer as a polymerization component is determined by:
It is desirable to make it 0.8 or less, more preferably 0.6 or less.

In dispersing the magnetic particles, the resin used may sometimes serve as a dispersant, but if necessary, a fatty acid, an aliphatic amine, a fatty acid metal salt, Phosphate ester, polyester oligomer, ammonium salt of monocarboxylic acid, titanium coupling agent, silane coupling agent, lecithin,
Animal and vegetable proteins, polycarboxylic acids and salts thereof, sodium pyrophosphate, sodium hexametaphosphate, casein, sodium ligninsulfonate, dipolyoxyethylene alkyl ether phosphate, tripolyoxyethylene alkyl ether phosphate, polyester polyamine, Known compounds such as polyoxyethylene stearylamine, polyoxyethylene oleylamine, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, and polyoxyethylene ceteryl ether can be used, but the present invention is not limited thereto. is not.

If necessary, additives such as a lubricant, an abrasive, a leveling agent, an antifoaming agent, a thickener, an antioxidant, an ultraviolet absorber, an antistatic agent, a preservative, and a filler are appropriately used. I can do it.

The image recording medium of the present invention comprises an elution-removable magnetic layer composed of at least a magnetic substance (A) and a resin (B) containing a monomer having an anionic functional group as a polymerizable component on a support. A conventional magnetic layer having no elution-removing property (hereinafter, referred to as the "eluting-removing magnetic layer") is provided between the elution-removing magnetic layer and the support or on the side of the support opposite to the elution-removing magnetic layer. It is also possible to provide a non-elution-removable magnetic layer). In addition, the purpose such as adhesion and durability between the support and the elution-removable magnetic layer, between the support and the non-elution-removable magnetic layer, or between the elution-removable magnetic layer and the non-elution-removable magnetic layer. In this case, an undercoat layer or an intermediate layer may be provided. further,
After image formation by elution removal, a protective layer or a printing layer may be provided according to the purpose of improving abrasion resistance, chemical resistance, durability and design. The protective layer at this time is
The magnetically recognizable image information may be transparent so as to be visible, or may be opaque with a hiding power that makes it invisible. In addition, undercoat layer, middle layer,
The protective layer may be composed of two or three or more layers.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings, but the present invention is not limited to these embodiments.

Embodiment FIG. 1 shows an example in which the image recording medium of the present invention is applied to a card-shaped information recording medium, and magnetic image information is formed as bar-code image information. In this embodiment, a non-elution-removable magnetic layer containing a magnetic material having a coercive force of 2750 Oersted is provided on the support, and a magnetic layer having a coercive force of 615 Oersted is provided thereon. Magnetic image information is provided. FIGS. 2, 3, and 4 illustrate the manufacturing process of the present embodiment in order as changes in the cross-sectional view of the card-shaped information recording medium of the present embodiment. FIG. 2 shows non-elution removal on a support. FIG. 3 is a cross-sectional view when a magnetic layer and an elution-removable magnetic layer are sequentially formed, FIG. 3 is a cross-sectional view when a resist image is formed on the elution-removable magnetic layer in FIG. 2, and FIG. 4 is a non-resist image in FIG. FIG. 2 is a cross-sectional view of a card-shaped information recording medium having a magnetic image portion finally formed after a portion is eluted and removed, each showing a cross-sectional view along the dotted line shown in FIG. 1.

Next, the manufacturing process of this embodiment will be described more specifically. (1) Synthesis of a resin containing an anionic functional group-containing monomer as a polymerization component From 40 parts by weight of methyl methacrylate, 40 parts by weight of butyl acrylate, 20 parts by weight of acrylic acid, and 2 parts by weight of AIBN (azobisisobutyronitrile) Is maintained at 100 ° C. in a nitrogen gas atmosphere.
The mixture was added dropwise to 90 parts by weight of dioxane over 3 hours, and 0.5 parts by weight of AIBN and 10 parts by weight of 1,4-dioxane were added. The resulting resin was obtained. The weight average molecular weight of this resin was 22,000.

(2) Non-elution-removable magnetic layer Magnetic material (barium ferrite, coercive force 2750 Oersted) 100 parts Toluene 70 parts MEK 70 parts Dispersant (phosphate ester) 5 parts Binder (vinyl chloride / vinyl acetate / 12.5 parts The above composition was dispersed for 4 hours using a paint conditioner to prepare a preliminary dispersion. Next, the following composition was added to this preliminary dispersion, and the mixture was stirred to obtain a magnetic coating liquid. Binder (urethane resin, 35% MEK solution) 35.5 parts Curing agent (polyisocyanate, 75% ethyl acetate solution) 1.5 parts This magnetic coating solution was placed on a support (188 μm white PET) at 10 μm. Coated to thickness. In addition, immediately after coating 200
A magnetic field of 0 G was applied to orient the magnetic particles.

(3) Elution-removing magnetic layer 215 parts of a resin containing a monomer containing an anionic functional group synthesized in (1) as a polymerization component and the following materials are mixed, and dispersed for 4 hours using a paint conditioner. did. Magnetic material (Co-γ-Fe ₂ O ₃ , coercive force: 615 Oersted) 100 parts MEK 100 parts Toluene 50 parts Cyclohexanone 50 parts The dispersion thus prepared is placed on the non-eluting and removable magnetic layer formed in the above (2). 5 μm. Also,
Similar to the non-elution-removable magnetic layer, a magnetic field of 2000 G was applied immediately after coating to orient the magnetic particles.

(4) Formation of resist image and elution removal of non-resist image area A bar code resist image was formed on the elution-removable magnetic layer thus formed by a fusion heat transfer printer. Thereafter, the card-shaped information recording medium on which the resist image was formed was immersed in an aqueous solution of NaOH having a pH of 12.5 for 10 seconds, washed with water, and the non-resist image portion was eluted and removed to form a bar-code magnetic image portion.

(5) Measurement of Electromagnetic Conversion Characteristics of Magnetic Image Area Finally, the non-elutable magnetic layer exposed after the elution-removable magnetic layer was eluted and removed was measured using a magnetic head.
Magnetic recording was performed at the recording density of BPI, and signals were reproduced by a magnetic head. The position of the used magnetic track is a portion surrounded by a dotted line denoted by reference numeral 2 in FIG. FIG. 5 is an enlarged view of the reproduced signal and shows good electromagnetic conversion characteristics. Further, FIG. 6 shows the result of reading the bar-code-like magnetic image portion using the same magnetic head, and it can be seen that a non-rewritable magnetic image portion is observed with a sufficient output.

[0022]

According to the present invention, it is possible to provide different magnetic information to each image recording medium, and when the magnetic information is used for security, an image recording with extremely high security is provided. The medium was realized.

[Brief description of the drawings]

FIG. 1 is a plan view of a card-shaped recording medium using the image recording medium of the present invention.

FIG. 2 is a cross-sectional view of the image recording medium of the present invention in which a non-elutable magnetic layer and an elution-removable magnetic layer are sequentially laminated on a support.

FIG. 3 shows the elution-removable magnetic layer of the image recording medium of FIG.
Sectional drawing of what formed the resist image.

FIG. 4 is a cross-sectional view of the image recording medium of the present invention after a non-resist image portion of the elution-removable magnetic layer is eluted and removed after a resist image is formed.

FIG. 5 is an enlarged view of a part of a signal read by a magnetic head after recording at a density of 210 BPI on a non-elution-removable magnetic layer.

FIG. 6 is an enlarged view of a part of a signal read by a magnetic head from a bar-code-shaped magnetic image portion formed by eluting an elution-removable magnetic layer in a non-resist image portion after a resist image is formed.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Bar code-shaped magnetic image part 2 Magnetic track part for performing normal rewritable magnetic recording on non-elution-removable magnetic layer 3 Elution-removable magnetic layer 4 Non-elution-removable magnetic layer 5 Support 6 Resist image

Continued on the front page (51) Int.Cl. ⁶ Identification code FI G06K 19/10 G06K 19/00 B G11B 5/702 R

Claims (2)

[Claims] 1. An image recording medium comprising a support and a layer comprising a resin (B) containing at least a magnetic material (A) and a monomer having an anionic functional group as a polymerization component as constituent components. 2. An image forming method which is performed by forming a resist image on the image recording medium according to claim 1 and then eluting and removing a non-registered image portion.