MAGNETIC RECORDING MEDIUM, METHOD FOR MANUFACTURING SAME, AND LAMINATE FOR HEAT TRANSFER

Abstract

A problem to be solved by the present invention is to provide a magnetic recording medium having a jet-black magnetic stripe which is not tinged with red. The present invention is directed to a magnetic recording medium including: a magnetic recording layer on a substrate; and a protective layer (a) on the magnetic recording layer, wherein the protective layer (a) contains an aniline coloring material. The magnetic recording medium is advantageous in that the magnetic stripe is jet-black and has excellent design properties, and therefore can be widely used for credit cards, bank cards and the like.

Claims

1. A magnetic recording medium comprising: a magnetic recording layer on a substrate; and a protective layer (a) on the magnetic recording layer, wherein the protective layer (a) contains an aniline coloring material.

2. The magnetic recording medium according to claim 1, wherein the aniline coloring material contains no chromium ion or has a chromium ion content of 2 ppm or less.

3. The magnetic recording medium according to claim 1, wherein the aniline coloring material is contained in an amount in the range of from 20 to 40% by mass, based on the mass of the protective layer (a).

4. The magnetic recording medium according to claim 1, wherein the magnetic recording layer contains carbon black, wherein the content of the carbon black in the magnetic recording layer is in the range of from 2 to 10% by mass.

5. The magnetic recording medium according to claim 1, wherein the protective layer (a) comprises a protective layer (a1) and a protective layer (a2) as viewed from the side in contact with the magnetic recording layer, wherein at least the protective layer (a1) is a layer containing the aniline coloring material.

6. The magnetic recording medium according to claim 1, which has an L value in the range of from 0 to 10, an a* value in the range of from 1 to +1, and a b* value in the range of from 1 to +1 in a CIE 1976 (L*a*b*) color space as observed from the surface side of the protective layer (a).

7. A laminate for heat transfer comprising: a protective layer (a) on a temporary support; and a magnetic recording layer on the protective layer (a), wherein the protective layer (a) is a layer containing an aniline coloring material.

8. A method for producing a magnetic recording medium, the method comprising the steps of: transferring the laminate for heat transfer according to claim 7 onto the substrate optionally with an adhesive layer interposed between the laminate and the substrate; and removing the temporary support.

Description

EXAMPLES

[0047] Hereinbelow, the present invention will be described in more detail with reference to the following specific Examples and Comparative Examples.

Example 1

<Preparation of a Coating Composition for Forming a Magnetic Recording Layer>

[0048] The components shown below were charged into a vessel and kneaded together to obtain a coating composition for forming a magnetic recording layer.

TABLE-US-00001 Barium ferrite 36.6 Parts by mass (MC-127, magnetic powder manufactured by Toda Kogyo Corp.) Vinyl chloride resin 6.9 Parts by mass (SOLBIN AL, manufactured by Nissin Chemical Industry Co., Ltd.) Polyurethane resin 7.7 Parts by mass (BURNOCK L7-750 (effective component: 35.0% by mass), manufactured by DIC Corporation) Carbon black 3.5 Parts by mass (Special Black 350, manufactured by Orion Engineered Carbons) Dispersant 0.2 Part by mass (Solsperse 5000, manufactured by Lubrizol Japan Limited) Methyl ethyl ketone 20.5 Parts by mass Toluene 21.9 Parts by mass Cyclohexanone 7.6 Parts by mass Isocyanate compound 5.1 Parts by mass (Hardener No. 10 (effective component: 37.5% by mass), manufactured by DIC Corporation)
<Preparation of a Coating Composition for Forming a Protective Layer (a1-1)>

[0049] The components shown below were charged into a vessel and kneaded together to obtain a coating composition for forming a protective layer (a1-1).

TABLE-US-00002 Cellulose acetate 2.4 Parts by mass (L-AC L-20, manufactured by Daicel Corporation) Cellulose acetate 4.6 Parts by mass (CAP504-0.2, propionate manufactured by Eastman Chemical Company) Aniline black (aniline 3.2 Parts by mass (toshiki coloring material) black 5036, manufactured by Tokyo Shikizai Industry Co., Ltd.) Tributyl acetylcitrate 2.0 Parts by mass Polyethylene wax 0.3 Part by mass Acetone 23.5 Parts by mass Ethyl acetate 23.5 Parts by mass Cyclohexanone 18.4 Parts by mass Toluene 19.6 Parts by mass Isocyanate compound. 2.7 Parts by mass (Hardener No 50 (effective component: 50% by mass), manufactured by DIC Corporation)
<Preparation of a Coating Composition for Forming a Protective Layer (a2-1)>

[0050] The components shown below were charged into a vessel and kneaded together to obtain a coating composition for forming a protective layer (a2-1).

TABLE-US-00003 Cellulose acetate 2.4 Parts by mass (L-AC L-20, manufactured by Daicel Corporation) Cellulose acetate 4.6 Parts by mass (CAP504-0.2, propionate manufactured by Eastman Chemical Company) Aniline black 3.2 Parts by mass (toshiki (aniline coloring material) black 5036, manufactured by Tokyo Shikizai Industry Co., Ltd.) Tributyl acetylcitrate 2.0 Parts by mass Acetone 23.5 Parts by mass Ethyl acetate 23.5 Parts by mass Cyclohexanone 18.4 Parts by mass Toluene 19.6 Parts by mass Isocyanate compound 2.7 Parts by mass (Hardener No. 50 (effective component: 50% by mass), manufactured by DIC Corporation)

<Adhesive>

[0051] The components shown below were charged into a vessel and mixed together to obtain an adhesive.

TABLE-US-00004 Vinyl chloride-vinyl 10.8 Parts by mass(SOLBIN M5, acetate-dicarboxylic manufactured by Nissin acid copolymer Chemical Industry Co., Ltd.) Polyurethane resin 18.0 Parts by mass (TS-03, manufactured by DIC Corporation) Methyl ethyl ketone 25.5 Parts by mass Toluene 45.5 Parts by mass

<Production of a Laminate for Heat Transfer>

[0052] A coating composition for forming a protective layer (a2-1) was applied onto a polyethylene terephthalate film, which is a temporary support, and dried to form a protective layer (a2-1) having a thickness of 0.4 m. A coating composition for foaming a protective layer (a1-1) was applied onto the protective layer (a2-1) and dried to form a protective layer (a1-1) having a thickness of 1.6 m. A coating composition for foaming a magnetic recording layer was applied onto the protective layer (a1-1) and dried to foam a magnetic recording layer having a thickness of 8 m. The adhesive was applied onto the magnetic recording layer and dried to form an adhesive layer having a thickness of 1.5 m. The laminate comprising the temporary support/protective layer (a2-1)/protective layer (a1-1)/magnetic recording layer/adhesive layer obtained by the above-mentioned method was used as a laminate for heat transfer.

<Production of a Magnetic Recording Medium>

[0053] The laminate for heat transfer was stacked on a polyvinyl chloride sheet (substrate) having a thickness of 100 m so that the adhesive layer of the laminate was in contact with the sheet, and subjected to hot-pressing at 120 C. and at 1 kg/cm.sup.2 for one second using Heat Seal Tester (manufactured by Tester Sangyo Co., Ltd.). Then, the temporary support was removed to obtain a laminate in which a magnetic stripe comprising the protective layer (a2-1), the protective layer (a1-1), the magnetic recording layer, and the adhesive layer was laminated on the polyvinyl chloride sheet.

[0054] Then, a polyvinyl chloride sheet having a thickness of 650 m and having a black printed layer on the surface and the laminate were stacked on one another. In this instance, they were stacked so that the black printed layer of the polyvinyl chloride sheet was in contact with the plane made of the polyvinyl chloride sheet having a thickness of 100 m constituting the laminate. The resultant stacked material was subjected to hot-pressing at 145 C. and at 10 kg/cm.sup.2 for 20 minutes using a platen press machine (manufactured by Toyo Seiki Seisaku-Sho, Ltd.) to produce a magnetic recording medium.

Example 2

[0055] <Preparation of a Coating Composition for Forming a Protective Layer (a1-2)>

[0056] The components shown below were charged into a vessel and kneaded together to obtain a coating composition for forming a protective layer (a1-2).

TABLE-US-00005 Cellulose acetate 2.4 Parts by mass (L-AC L-20, manufactured by Daicel Corporation) Cellulose acetate 4.6 Parts by mass (CAP504-0.2, propionate manufactured by Eastman Chemical Company) Aniline black 5.7 Parts by mass (toshiki (aniline coloring material(D)) black 5036, manufactured by Tokyo Shikizai Industry Co., Ltd.) Tributyl acetylcitrate 3.6 Parts by mass Acetone 23.5 Parts by mass Ethyl acetate 23.5 Parts by mass Cyclohexanone 18.4 Parts by mass Toluene 19.6 Parts by mass Isocyanate compound 2.7 Parts by mass(Hardener No. 50 (effective component: 50%), manufactured by DIC Corporation)
<Formulation of a Coating Composition for Forming a Protective Layer (a2-2)>

[0057] The components shown below were charged into a vessel and kneaded together to obtain a coating composition for forming a protective layer (a2-2).

TABLE-US-00006 Cellulose acetate 2.4 Parts by mass (L-AC L-20, manufactured by Daicel Corporation) Cellulose acetate 4.6 Parts by mass (CAP504-0.2, propionate manufactured by Eastman Chemical Company) Aniline black 5.7 Parts by mass (toshiki (aniline coloring material) black 5036, manufactured by Tokyo Shikizai Industry Co., Ltd.) Tributyl acetylcitrate 3.6 Parts by mass Acetone 23.5 Parts by mass Ethyl acetate 23.5 Parts by mass Cyclohexanone 18.4 Parts by mass Toluene 19.6 Parts by mass Isocyanate compound 2.7 Parts by mass(Hardener No. 50 (effective component: 50% by mass), manufactured by DIC Corporation)

[0058] A laminate for heat transfer and a magnetic recording medium were produced in substantially the same manner as in Example 1 except that, instead of the coating composition for foaming a protective layer (a1-1), a coating composition for forming a protective layer (a1-2) was used, and that, instead of the coating composition for forming a protective layer (a2-1), a coating composition for forming a protective layer (a2-2) was used.

Example 3

[0059] <Preparation of a Coating Composition for Forming a Protective Layer (a1-3)>

[0060] The components shown below were charged into a vessel and kneaded together to obtain a coating composition for forming a protective layer (a2-3).

TABLE-US-00007 Cellulose acetate 2.4 Parts by mass (L-AC L-20, manufactured by Daicel Corporation) Cellulose acetate 4.6 Parts by mass (CAP504-0.2, propionate manufactured by Eastman Chemical Company) Aniline black 5.7 Parts (aniline coloring material) by mass (toshiki black 5036, manufactured by Tokyo Shikizai Industry Co., Ltd.) Tributyl acetylcitrate 2.0 Parts by mass Polyethylene wax 0.3 Part by mass Acetone 23.5 Parts by mass Ethyl acetate 23.5 Parts by mass Cyclohexanone 18.4 Parts by mass Toluene 19.6 Parts by mass Isocyanate compound 2.7 Parts by mass(Hardener No. 50 (effective component: 50% by mass), manufactured by DIC Corporation)
<Preparation of a Coating Composition for Forming a Protective Layer (a2-3)>

[0061] The components shown below were charged into a vessel and kneaded together to obtain a coating composition for forming a protective layer (a2-3).

TABLE-US-00008 Cellulose acetate 2.4 Parts by mass (L-AC L-20, manufactured by Daicel Corporation) Cellulose acetate 4.6 Parts by mass (CAP504-0.2, propionate manufactured by Eastman Chemical Company) Acetone 23.5 Parts by mass Ethyl acetate 23.5 Parts by mass Cyclohexanone 18.4 Parts by mass Toluene 19.6 Parts by mass Isocyanate compound 2.7 Parts by mass(Hardener No. 50 (effective component: 50% by mass), manufactured by DIC Corporation)

[0062] A laminate for heat transfer and a magnetic recording medium were produced in substantially the same manner as in Example 1 except that, instead of the coating composition for foaming a protective layer (a1-1), a coating composition for foaming a protective layer (a1-3) was used, and that, instead of the coating composition for forming a protective layer (a2-1), a coating composition for foaming a protective layer (a2-3) was used.

Comparative Example 1

[0063] <Preparation of a Coating Composition for Forming a Protective Layer (a1-4)>

[0064] The components shown below were charged into a vessel and kneaded together to obtain a coating composition for forming a protective layer (a1-4).

TABLE-US-00009 Cellulose acetate 2.4 Parts by mass (L-AC L-20, manufactured by Daicel Corporation) Cellulose acetate 4.6 Parts by mass (CAP504-0.2, propionate manufactured by Eastman Chemical Company) Polyethylene wax 0.3 Part by mass Acetone 23.5 Parts by mass Ethyl acetate 23.5 Parts by mass Cyclohexanone 18.4 Parts by mass Toluene 19.6 Parts by mass Isocyanate compound 2.7 Parts by mass(Hardener No. 50 (effective component: 50% by mass), manufactured by DIC Corporation)
<Formulation of a Coating Composition for Forming a Protective Layer (a2-4)>

[0065] The components shown below were charged into a vessel and kneaded together to obtain a coating composition for forming a protective layer (a2-4).

TABLE-US-00010 Cellulose acetate 2.4 Parts by mass (L-AC L-20, manufactured by Daicel Corporation) Cellulose acetate 4.6 Parts by mass (CAP504-0.2, propionate manufactured by Eastman Chemical Company) Acetone 23.5 Parts by mass Ethyl acetate 23.5 Parts by mass Cyclohexanone 18.4 Parts by mass Toluene 19.6 Parts by mass Isocyanate compound 2.7 Parts by mass(Hardener No. 50 (effective component: 50% by mass), manufactured by DIC Corporation)

[0066] A laminate for heat transfer and a magnetic recording medium were produced in substantially the same manner as in Example 1 except that, instead of the coating composition for foaming a protective layer (a1-1), a coating composition for foaming a protective layer (a1-4) was used, and that, instead of the coating composition for forming a protective layer (a2-1), a coating composition for foaming a protective layer (a2-4) was used.

(Comparative Example 2

[0067] <Formulation of a Coating Composition for Forming a Protective Layer (a1-5)>

[0068] The components shown below were charged into a vessel and kneaded together to obtain a coating composition for forming a protective layer (a1-5).

TABLE-US-00011 Cellulose acetate 2.4 Parts by mass (L-AC L-20, manufactured by Daicel Corporation) Cellulose acetate 4.6 Parts by mass (CAP504-0.2, propionate manufactured by Eastman Chemical Company) Carbon black 3.2 Parts by mass (Degussa FW200, manufactured by Orion Engineered Carbons) Dispersant 0.4 Part by mass (Solsperse 5000, manufactured by Lubrizol Japan Limited) Tributyl acetylcitrate 2.0 Parts by mass Polyethylene wax 0.3 Part by mass Acetone 23.5 Parts by mass Ethyl acetate 23.5 Parts by mass Cyclohexanone 18.4 Parts by mass Toluene 19.6 Parts by mass Isocyanate compound 2.7 Parts by mass(Hardener No. 50 (effective component: 50% by mass), manufactured by DIC Corporation)
<Preparation of a Coating Composition for Forming a Protective Layer (a2-5)>

[0069] The components shown below were charged into a vessel and kneaded together to obtain a coating composition for forming a protective layer (a2-5).

TABLE-US-00012 Cellulose acetate 2.4 Parts by mass (L-AC L-20, manufactured by Daicel Corporation) Cellulose acetate 4.6 Parts by mass (CAP504-0.2, propionate manufactured by Eastman Chemical Company) Carbon black 3.2 Parts by mass (Degussa FW200, manufactured by Orion Engineered Carbons) Dispersant 0.4 Part by mass (Solsperse 5000, manufactured by Lubrizol Japan Limited) Tributyl acetylcitrate 2.0 Parts by mass Acetone 23.5 Parts by mass Ethyl acetate 23.5 Parts by mass Cyclohexanone 18.4 Parts by mass Toluene 19.6 Parts by mass Isocyanate compound 2.7 Parts by mass(Hardener No. 50 (effective component: 50% by mass), manufactured by DIC Corporation)

[0070] A laminate for heat transfer and a magnetic recording medium were produced in substantially the same manner as in Example 1 except that, instead of the coating composition for foaming a protective layer (a1-1), a coating composition for foaming a protective layer (a1-5) was used, and that, instead of the coating composition for forming a protective layer (a2-1), a coating composition for foaming a protective layer (a2-5) was used.

Test Items and Test Results

<Test for Jet-Black Color Properties>

[0071] With respect to the obtained magnetic recording medium, values in a CIE 1976 (L*a*b*) color space were measured from the plane side made of the protective layer of the magnetic stripe of the magnetic recording medium using Spectro Color Meter SE2000, manufactured by Nippon Denshoku Industries Co. Ltd. A magnetic recording medium in which the L value was in the range of from 0 to 10, the a* value was in the range of from 1 to +1, and the b* value was in the range of from 1 to +1 was rated . A magnetic recording medium in which any of the above values was outside of the above-mentioned respective ranges was rated x.

<Test for Abrasion Resistance>

[0072] Using Card Reader Writer (manufactured by Hitachi-Omron Terminal Solutions, Corp.), a reading operation for the magnetic recording medium was repeated 20,000 times. A magnetic recording medium such that, after the reading operation was repeated 20,000 times, the medium was usable without having a defect in the protective layer and the magnetic recording layer constituting the magnetic stripe was considered to have excellent abrasion resistance and rated . A magnetic recording medium such that, after the reading operation was repeated less than 20,000 times, the magnetic recording layer of the magnetic stripe wore due to abrasion with the magnetic head to be partially or completely lost was considered to have poor abrasion resistance and rated x.

<Test for Interference Fringe>

[0073] With respect to the magnetic stripe of the obtained magnetic recording medium, the reflected light of a fluorescent lighting was visually examined to check whether an interference fringe was seen. A magnetic recording medium such that no interference fringe could be confirmed was rated , and a magnetic recording medium such that an interference fringe could be confirmed was rated x.

TABLE-US-00013 TABLE 1 Test for jet-black color properties Test for Test for Evalu- abrasion interference L a* b* ation resistance fringe Example 1 9.5 0.2 0.2 Example 2 9.2 0.2 0.8 x Example 3 9.8 0.1 0.4 x Comparative 10.6 0.3 1.1 x Example 1 Comparative 11.2 0 0.4 x Example 2