JP2758650B2 - Manufacturing method of magnetic sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method of manufacturing a magnetic sheet useful for a card for an automatic ticket selling system such as a ticket, a coupon, a commuter pass, a credit card, a road pass, a betting ticket, and the like. It is about.

(Prior Art) A recording method using a magnetic recording medium has been developed due to advances in various terminal devices and systems, and in particular, magnetic cards have been rapidly spreading in recent years. Among them, a magnetic sheet in which one side of a support is a plastic sheet or paper and one side of which is magnetically recordable is widely used. These cards are mass-produced by using a plastic sheet or paper as a support and attaching the magnetic recording sheet to the support with an adhesive or applying a magnetic recording material to the support. In the production of such a magnetic recording sheet, an adhesive used for bonding or as a binder for a paint usually contains an organic solvent or water as a solvent. Therefore, these solvents must be evaporated by heating at the stage of lamination or coating layer drying. In the case of the bonding method, floating occurs at the lamination part, and curl occurs due to elongation of the sheet due to heating. Or When such a sheet is a heat-sensitive paper, various drawbacks accompany, such as unnecessary color development due to heating. In the case of a magnetic sheet in which a magnetic recording material is applied to a support, a polyester resin is generally used as a binder when a magnetic recording layer is formed. There are difficulties in sex. Therefore, there is a risk that a commuter pass or the like frequently used becomes unusable. In addition, the surface of the magnetic recording layer is colored brown or black due to the use of a magnetic substance, and it is practically impossible to print on this surface. Therefore, printing is limited to one side, and the printing is limited. At present, it is not possible to express a print full of fashion sense because of the space occupied by information.

(Problems to be Solved by the Invention) The present invention does not involve the drawback that the coloring of the recording layer surface does not appear on the surface as described above, and the bonded portion does not float or curl. It is an object to provide a method for producing high quality magnetic sheets that can be printed as information and, on the other hand, printed with a fashion sense.

(Means for Solving the Problems) The present inventors have conducted various studies in order to solve the above problems, and as a result, completed the invention having the following configuration. That is, supports (1) and (2) made of two opaque sheets
A magnetic recording layer (3) made of a mixture containing a ferromagnetic powder and an electron beam-curable resin as main components, superposed, and then irradiated with an electron beam from above the support. It is a manufacturing method of.

(Function) In the above configuration, as the material of the supports (1) and (2) made of an opaque sheet, various materials can be mentioned, for example, plastics such as polyethylene, polypropylene, polyvinyl chloride, polyvinyl acetate, and polyester. Films, metal foils such as stainless steel foils and aluminum foils, high quality papers, art papers, coated papers, cast papers, thermal papers, carbonless papers, papers such as electrostatic recording papers, and synthetic papers are used.

When paper is used for the support, various antistatic agents, chromium oxide for improving abrasion resistance, α-alumina powder, and lubricating properties may be used in the coat layer of these papers as necessary. It may contain a silicone oil, a fluorine compound and a water-proofing agent for application, or may have one or more overcoat layers composed mainly of various resins containing these additives on these papers. Layers can also be provided.

Further, the structure of the supports (1) and (2) is not limited to a case where both materials are made of the same material such as plastic films, and also a case where both materials are made of different materials such as a combination of a plastic film and paper. Including.

The magnetic recording layer (3) is mainly composed of γ-Fe ₂ O ₃ and Co-doped γ-F
e ₂ O ₃ , barium ferrite, (B _a O, 6Fe ₂ O ₃ ), CrO ₂ , Fe
-A ferromagnetic powder such as a magnetic metal powder such as a Co alloy or a Fe-Co-Ni alloy, and a mixture mainly composed of an electron beam-curable resin or the like. Is a monomer or oligomer having a radical polymerizable double bond in the molecule, for example, oligomers such as polyester acrylate, polyether acrylate, polyurethane acrylate, epoxy acrylate, unsaturated polyester acrylate, acrylic acid, methyl acrylate, acrylic Examples include monomers such as butyl acid, acrylamide, ethylene glycol diacrylate, and trimethylolpropane triacrylate.

Of course, the present invention is not limited to these adhesives, and two or more adhesives can be used. In the magnetic recording layer, a colored pigment such as carbon black, a surfactant for improving the dispersibility of the magnetic powder, a silane coupling agent, or the like may be used as an antistatic agent, if necessary.

Here, the mixing ratio of the magnetic material powder and the electron beam curable resin is from magnetic material powder / electron beam curable resin (weight ratio) = 85/15 to 15/85 in consideration of magnetic properties and adhesiveness. Preferably 70
It is adjusted in the range of / 30 to 30/70.

The mixture of these magnetic powders and the electron beam curable resin,
For example, a bar coater, a gravure coater, a roll coater, a fountain coater, a hot melt coater, or the like is applied to the back surface of one of the supports (1) and (2), and is left in a parallel magnetic field for orientation treatment. Then, the other support is overlapped, and an electron beam is irradiated from above the support to simultaneously cure and bond the resin.

The coating amount for forming the magnetic recording layer is adjusted in the range of ^{2 to} 30 g / m ² , more preferably 3 to 25 g / m ² by dry weight. If the amount is less than 2 g / m ² , the effect of the application of the present invention cannot be obtained, and if it exceeds 30 g / m ² , there is little necessity in view of the intended effect.

As an electron beam irradiation method, for example, a linear cathode method, a scanning method, a curtain beam method, a broad beam method, or the like is employed. When the electron beam is irradiated, the accelerating voltage is about 100 to 300 kv, and the irradiation amount is preferably 0.1 to 15 Mrad, more preferably about 1 to 10 Mrad. If the amount is less than 1 Mrad, the adhesion is insufficient, and excessive electron beam irradiation exceeding 15 Mrad may cause discoloration.

Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but is not limited thereto.

Example 1 Preparation of electron beam-curable magnetic paint 120 parts of r-Fe ₂ O ₃ (trade name: MX-450 manufactured by Toda Kogyo Co., Ltd.) carbon black (trade name: Mitsubishi Carbon Black MA
-600 manufactured by Mitsubishi Kasei Corporation 5 parts Dispersant (soybean oil refined lecithin) 3 parts Electron beam curable resin (urethane acrylate, trade name: E
BECRYL4830, manufactured by UCB) 50 parts Ethylene glycol diacrylate 200 parts The composition was mixed for 8 hours using a ball mill and filtered to obtain an electron beam-curable magnetic paint.

The electron beam-curable magnetic paint is applied on a polyethylene terephthalate support (2) having a film thickness of 30 microns so as to have a dry weight of 8 g / m ² (application thickness of 10 microns).
After standing for 1 second in a parallel magnetic field of 000 gauss for orientation treatment, an art paper (trade name: Kanto both sides <110>, manufactured by Kanzaki Paper Co., Ltd.) support (1) was overlaid and pressed using a roller. Then, using an electron curtain type electron beam irradiation device (CB-150, manufactured by ESI) at an accelerating voltage of 165 KV,
Irradiation with Mrad was performed to cure the film, thereby forming an electron beam cured magnetic sheet.

Comparative Example 1 Preparation of magnetic paint 120 parts of r-Fe ₂ O ₃ (trade name: MX-450 manufactured by Toda Kogyo Co., Ltd.) carbon black (trade name: Mitsubishi Carbon Black MA
-600 manufactured by Mitsubishi Kasei Corporation 5 parts Dispersant (soybean oil refined lecithin) 3 parts Alkyd resin (trade name; Toxinol 1200-50 manufactured by Tokushima Essential Oil Co., Ltd.) 130 parts Amino resin (trade name: Tesmin 210-60 Tokushima Essential Oil Co., Ltd.) 120 parts Toluene 150 parts Methyl ethyl ketone 150 parts This composition was placed in a horizontal motion type fully closed ball mill (WILL.AB).
The mixture was mixed with an ACHOFEN Dynomill for 8 hours and filtered to obtain a magnetic paint.

This paint is applied to a polyethylene terephthalate support (2)
Coated on the top so that the dry weight is 8 g / m ² (coating thickness is 10 μm), left for 1 second in a parallel magnetic field of 2000 gauss, and orientation-treated. Then, art paper (trade name: Kanto both sides <110) >
The support (1) (manufactured by Kanzaki Paper Co., Ltd.) was pressure-bonded using an overlapping roller, heated and dried to form a magnetic sheet.

Example 2 In the same manner as in Example 1 except that the support (2) in Example 1 was replaced with a PET film and (1) was replaced with a thermal paper (trade name: synthetic paper, thermal paper Kanzaki Paper Co., Ltd.). An electron beam cured magnetic sheet was formed.

Example 3 In Example 1, the supports (1) and (2) were both art papers (trade name: both sides of Kanto <110>, manufactured by Kanzaki Paper Co., Ltd.)
A magnetic sheet was formed in the same manner as in Example 1 except that the magnetic sheet was changed.

Comparative Example 2 In the same manner as in Comparative Example 1, except that the support (2) was replaced with a PET film and (1) was replaced with a thermal paper (trade name: synthetic paper thermal paper Kanzaki Paper Co., Ltd.). An electron beam cured magnetic sheet was formed.

Comparative Example 3 In Comparative Example 1, both the supports (1) and (2) were art paper (trade name: both sides of Kanto <110>, manufactured by Kanzaki Paper Co., Ltd.)
An electron beam-cured magnetic sheet was formed in the same manner as in Comparative Example 1 except that the composition was changed to.

The six types of magnetic sheets thus obtained were tested by the following method, and the performance was evaluated. The results are shown in Table 1.

Evaluation criteria Adhesive strength: Peel adhesive strength was measured from JIS-K-6854.

○: High peel strength between support and magnetic recording layer ×: Low peel strength between support and magnetic recording layer Curl: Magnetic card reader / writer unit CRS-750
(Manufactured by General Business) was used.

○: Available ×: Not available (due to curl) (Effects) As is clear from Table 1, the magnetic sheet obtained in the present invention has strong adhesion, is hard to peel off, has excellent water resistance and abrasion resistance, has no curl, and can be double-sided printed. It was excellent in practicality with high fashion sense.

[Brief description of the drawings]

 FIG. 1 is a sectional view showing a magnetic sheet of the present invention. 1: support 3: electron beam-cured magnetic recording layer 2: support

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G11B 5/80 G11B 5/84 B42D 15/10 501

Claims (1)

(57) [Claims] A magnetic recording layer (3) composed of a mixture mainly composed of a ferromagnetic powder and an electron beam curable resin is provided between supports (1) and (2) composed of two opaque sheets. A method for producing a magnetic sheet, comprising: irradiating an electron beam from above a support after providing and superposing.