JPH06274860A - Heat sensitive recording type magnetic recording medium - Google Patents

Abstract

PURPOSE:To increase printing contrast by enhanced hiding power by treating aluminum powder as the principal component of a hiding layer with at least one of silane, titanate and aluminum coupling agents. CONSTITUTION:When a magnetic recording layer 2, a hiding layer 3, a heat sensitive recording layer 4 and a protective layer 5 are successively laminated on one side of a substrate 1, aluminum powder as the principal component of the hiding layer 3 is treated with one or more of silane, titanate and aluminum coupling agents and the surface is coated with an org. substance. Surface fog is prevented during storage over a long period of time or in an environment, at high temp. and humidity and the strength of the hiding layer as a coating film is enhanced. Cohesive power in the coating film at the time of highly filling the aluminum powder is enhanced and printing contrast is increased by enhanced hiding power.

Description

Detailed Description of the Invention

[0001]

[Industrial field of use] Visible information is recorded using a thermal head in order to visually check the usage status of prepaid cards used in public telephones, railroads, games, stores selling various goods, etc. In particular, the present invention relates to a heat-sensitive recording type magnetic recording medium in which the heat-sensitive recording layer has good storability.

[0002]

2. Description of the Related Art Conventionally, a magnetic recording layer on one surface of a substrate,
A heat-sensitive recording magnetic recording medium in which a hiding layer, a heat-sensitive recording layer containing a dye precursor and a color-developing substance as main components, and a protective layer are laminated in this order is well known (for example, JP-A-4-201).
396). In such a recording medium, as a masking layer, a masking metal powder such as scale-like aluminum powder is dispersed in a resin binder to mask the color of the magnetic recording layer,
It has been attempted to increase the contrast or sharpness of visible information on the thermosensitive recording layer.

In order to produce scale-like metal powder such as aluminum powder, oleic acid is used as a grinding aid in the powdering process using a grinding machine such as a ball mill.
A fatty acid such as stearic acid is used.

[0004]

Since these fatty acids have a color developing action on the dye precursor in the heat-sensitive recording layer, if they remain, they cause fog on the background during long-term storage. In order to solve this problem, it is necessary to completely remove the residual fatty acids used during the production of aluminum powder, but aluminum powder is a metal powder with a large surface area and its surface activity is strong, so there is a risk of ignition. Yes Do not remove or replace with an organic solvent. Another problem is that since aluminum powder has poor dispersibility, the packing density does not increase sufficiently and sufficient hiding power cannot be obtained.

Therefore, the object of the present invention is to improve the quality of visible information (printing), prevent the background fogging under the condition of long-term storage and high temperature and high humidity, and improve the coating film strength of the hiding layer. Is to improve the cohesive force of the coating film at the time of high filling, and therefore to improve the printing contrast by increasing the hiding.

[0006]

According to the present invention, a magnetic recording layer, a hiding layer, a thermosensitive recording layer containing a dye precursor and a color developing material as main components, and a protective layer are laminated in this order on one surface of a substrate. In the heat-sensitive recording magnetic recording medium, the aluminum powder as the main component of the hiding layer is treated with at least one of a silane-based, titanate-based, and aluminum-based coupling agent. If necessary, a heat-sensitive recording layer and a protective layer may be laminated in this order on the other surface of the base material to perform heat-sensitive recording on the front and back sides.

[0007]

Function: The dye precursor in the heat-sensitive recording layer turns an acidic substance into a color-developing substance to promote color development. When a heat-sensitive recording layer is provided on the magnetic recording layer side of a magnetic card, scaly aluminum powder is generally used because of its excellent hiding power, but most commercial products are used in the manufacturing process. Oleic acid and stearic acid remain, and as described above, the dye precursor exerts a color developing action to cause background fog. Therefore, it is sufficient to remove these fatty acids, but when removed, the activity of the aluminum powder surface is strong, and there is concern that ignition due to oxidation or luminance reduction due to surface oxidation during storage of the aluminum powder may occur. Therefore, the surface was coated with a silane-based, titanium-based, or aluminum-based coupling agent, which can be relatively easily treated in the manufacturing process, to stabilize the surface. Also,
In the hiding layer coating film forming the hiding layer, the binding force between the binder and the aluminum powder is increased, a large amount of the aluminum powder can be filled, the hiding power is increased, and the print contrast can be increased.

Next, the present invention will be described in detail. In the present invention, as shown in FIG. 1, a magnetic recording layer 2, a concealing layer 3 containing a metal powder, and a heat-sensitive recording layer 4 containing a dye precursor and a developer as main components are formed on one surface of a substrate 1. , And the protective layer 5 are laminated in this order to form a thermosensitive recording magnetic recording medium, and a printing layer is usually formed between the thermosensitive recording layer and the protective layer. Alternatively, as shown in FIG. 2, the heat-sensitive recording layer 6 and the protective layer 7 may be laminated in this order on the other surface of the substrate 1. Further, it may have other layers as required. For example, a primer layer may be provided between the hiding layer and the heat-sensitive recording layer to ensure chemical resistance, bondability, and smooth contact with a thermal printer.

The materials, thicknesses and forming methods that can be used for the respective layers of the recording medium of the present invention are shown below. (1) Material (a) Substrate Polyethylene terephthalate, polycarbonate, vinyl chloride, paper, or a composite material thereof.

(B) Magnetic recording layer Magnetic material: barium ferrite, γ-iron oxide, iron, etc. Binder: Polyurethane, vinyl chloride / vinyl alcohol / vinyl acetate copolymer, acrylic resin, nitrocellulose resin, polyester resin and blends thereof. Curing agent: Polymer such as tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, or polyisocyanate adducted to polyhydric alcohol.

(C) Concealing layer Aluminum powder: Aluminum powder having a particle size of 5 to 20 μm, which is surface-treated with a coupling agent shown below. -Vinyltriethoxysilane-Vinyltris (β-methoxyethoxy) silane, -γ-methacryloxypropyltrimethoxysilane, -γ-glycidoxypropyltrimethoxysilane-β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane , N-β- (aminoethyl) γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ -Aminopropyltrimethoxysilane, -γ-mercaptopropyltrimethoxysilane, -γ-chloropropyltrimethoxysilane, -isopropyltriisostearoyl titanate, -isopropyldodecylbenzenesulfonyl titanate, -isopropyltris (dioc Tyl phosphite) titanate, tetraoctyl bis (ditridecyl phosphite) titanate, bis (dioctyl pyrophosphate) oxyacetate titanate, bis (dioctyl pyrophosphate) ethylene titanate, isopropyl trioctanoyl titanate, isopropyl dimethacryl Isostearoyl titanate, isopropyl isostearoyl diacrylic titanate, isopropyl tricumylphenyl titanate, isopropyl tri (N-amidoethyl aminoamino) titanate, dicumyl phenyloxyacetate titanate, diisostearoyl ethylene titanate, acetoalkoxy Aluminum diisopropylate. Binder: Vinyl chloride resin, vinyl chloride / vinyl acetate copolymer, vinyl chloride / vinyl acetate / vinyl alcohol copolymer, acrylic resin, polyester resin, nitrocellulose resin, urethane resin,

(D) Thermal recording layer Dye precursor example (leuco dye): crystal violet lactone, 3-diethylamino-7-cyclohexylaminofluorane, 3-diethylamino-6-methyl-7
-Anilinofluorane, 3-diethylamino-7-dibenzylaminofluorane, 3-diethylamino-6-methyl-7-xylidinofluorane, 3-diethylamino-7-chlorofuran, 3-diethylamino-6-methyl- 7-p-butylanilinofluorane, 3-diethylamino-5-methyl-7-t-butylfluorane, 3-cyclohexylamino-6-chlorofluorane, 3-pyrrolidino-6-methyl-7-anilinofluor Oran, 3-pyrrolidino-7-cyclohexylaminofluorane, 3-
Piperidino-6-methyl-7-toluidinofluorane,
3-piperidino-6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7-chlorofluorane, 3-dibutylamino-6-methyl-7-anilinofluorane, 2- (N- Phenyl-N-ethyl) aminofluorane, 2-anilino-3-methyl-6- (N-
Ethyl-p-toluidino) fluorane, 3- (N-methylcyclohexylamino) -6-methyl-7anilinofluorane. Developer: 4,4'-isopropylidenediphenol,
4,4'-isopropylidene bis (2-chlorophenol), 4,4'-isopropylidene bis (2-tert-butylphenol), 4-phenylphenol, 4
-Hydroxydiphenyl, 4,4'-benzylidene diphenol, 4,4'-thiobis (6-tert-butyl-3-methylphenol), 4,4'-secondary butylidene diphenol, 4,4 '-(1 -Methyl-
(Normal-hexylidene) diphenol, 4-hydroxyacetophenone, 4,4'-cyclohexylidene diphenol, 4,4'-cyclohexylidenebis (2-methylphenol), 4,4'-isopropylidenebis (2-methyl) Phenol), 4,4'-ethylenebis (2-methylphenol), 4,4'-cyclohexylidenebis (2-isopropylphenol), methyl-4
-Hydroxybenzoate, phenyl-4-hydroxybenzoate, 2,2'-dihydroxyphenyl, 2,
2'-methylenebis (4-chlorophenol), 2,
2'-methylenebis (4-methyl-6-t-butylphenol), 2,2'-bis (4'-hydroxyphenyl) propane, 1,1'-bis (4-hydroxyphenol) -cyclohexane, phenol resin, bis (4-
Hydroxyphenyl) sulfone, 4-hydroxy-
4'-isopropyloxydiphenyl sulfone, di-
(3-allyl-4-hydroxyphenyl) sulfone, binder: polyvinyl alcohol, methylene cellulose, hydroxyethyl cellulose, acrylic resin emulsion

(E) Protective layer UV curable resin (ink), electron beam curable resin (ink)

(2) Thickness Next, the thickness of each layer is preferably in the following range. Magnetic recording layer 10 to 15 μm Concealing layer 0.5 to 3 μm Thermal recording layer 2.5 to 6 μm Protective layer 0.5 to 2 μm

(3) Manufacturing Method Next, the following method can be used for manufacturing each layer. Magnetic recording layer: Gravure, knife, bar, roll, comma coater and screen printing Concealment layer: Same as above Thermal recording layer: Same as above Protective layer: Offset printing

Next, examples of the present invention will be described. The thickness of each layer in the examples and comparative examples was as follows. Magnetic recording layer 15 μm Concealing layer 2 μm Thermal recording layer 4 μm Protective layer 2 μm (Protective layer was cured by high pressure mercury lamp after UV printing ink was offset printed) Examples 1, 2, 3 (a) Base material 188 μm polyethylene terephthalate (E22 manufactured by Toray Industries, Inc.) (b) Magnetic recording layer Barium ferrite (MC127 manufactured by Toda Kogyo Co., Ltd.) 100 parts by weight Tripolymer of vinyl chloride / vinyl acetate / vinyl alcohol (Eslec A manufactured by Sekisui Chemical Co., Ltd.) 15 parts by weight Parts Polyurethane elastomer (Nipporan 3113 manufactured by Nippon Polyurethane Industry Co., Ltd.) 60 parts by weight Curing agent (Coronate L manufactured by Nippon Polyurethane Industry Co., Ltd.) 20 parts by weight Methyl ethyl ketone 40 parts by weight Toluene 30 parts by weight The above composition is sufficiently mixed and dispersed, It was applied to a substrate and heat cured. (C) Aluminum powder (I) 20 parts by weight of aluminum paste (Alpaste 7640NS manufactured by Toyo Aluminum Co., Ltd.) was added to 100 parts of toluene.
It is put in a weight part and stirred for 30 minutes with a high-speed impeller, and the aluminum powder is filtered out. After performing the same operation 5 times, 3 parts by weight of isopropyltriisostearoyl titanate and 100 parts by weight of toluene were added, the mixture was stirred at high speed for 30 minutes, allowed to stand for 24 hours, and filtered to prepare an aluminum powder I. (II) Aluminum powder II was prepared in the same manner as in (I) using acetoalkoxyaluminum diisopropylate. (III) Using vinyltriethoxysilane as in (I): Aluminum powder III was prepared. (D) Concealing layer Aluminum powder 100 parts by weight Acrylic resin (Dianal BR50 manufactured by Mitsubishi Rayon Co., Ltd.) 30 parts by weight Methyl ethyl ketone 80 parts by weight Toluene 80 parts by weight Aluminum powder I was used as the aluminum powder in Example 1, aluminum. Example 2 uses the powder II, and Example 3 uses the aluminum powder III. The acrylic resin was dissolved in methyl ethyl ketone and toluene, aluminum powder was added, and the mixture was stirred with a high-speed impeller. (E) Heat-sensitive recording layer Liquid A Fluoran leuco dye (TG-31 manufactured by Nippon Kayaku Co., Ltd.) 10 parts by weight Acrylic emulsion (Movinyl 730 manufactured by Hoechst Synthetic Co., Ltd.) 20 parts by weight Water 5 parts by weight Liquid B 4-hydroxy- 4'Isopropyloxydiphenyl sulfone 10 parts by weight Acrylic emulsion (Movinyl 730 manufactured by Hoechst Synthetic Co., Ltd.) 20 parts by weight Water 5 parts by weight Solution A and solution B were mixed at a ratio of 1: 1 and mixed by stirring with a high-speed impeller.

COMPARATIVE EXAMPLE 1 The aluminum powder of Example was replaced with Alpaste 7640NS.
The product obtained by stirring and filtering once with toluene was used.

Comparative Example 2 The aluminum powder used in the example was treated with toluene five times and was not treated with a coupling agent.

[0019]

[Table 1]

[0020]

EFFECTS OF THE INVENTION As is clear from Table 1, by removing fatty acids such as oleic acid and stearic acid used in the manufacturing process of scaly aluminum powder, and further treating them with an organometallic coupling material. The coating strength of the hiding layer is increased, and the storage characteristics are further improved. Those in which the removal of the fatty acid was insufficient and which was not treated with the coupling agent had poor coating film strength and storage properties of the hiding layer (Comparative Example 1). If the fatty acid is sufficiently removed, the one not treated with the coupling agent does not cause fogging, but the coating strength is weak (Comparative Example 2). As described above, when the fatty acid is sufficiently removed and the surface is coated with an organometallic coupling agent and stabilized, the binding force between the binder and the aluminum powder in the hiding layer coating film forming the hiding layer becomes high, A large amount of aluminum powder can be filled, the hiding power is increased, and the print contrast can be increased.

[Brief description of drawings]

FIG. 1 is a sectional view schematically showing the constitution of the present invention.

FIG. 2 is a sectional view schematically showing another structure of the present invention.

[Explanation of symbols]

 1 Base Material 2 Magnetic Recording Layer 3 Concealing Layer 4 Thermal Recording Layer 5 Protective Layer 6 Thermal Recording Layer 7 Protective Layer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location B41M 5/26 B42D 15/10 501 D 9111-2C 551 A 9111-2C G06K 19/06 G07F 7 / 08 G11B 5/84 Z 7303-5D 9256-3E G07F 7/08 A

Claims (3)

[Claims] 1. A magnetic recording layer, a hiding layer, and
A heat-sensitive recording layer containing a dye precursor and a color-developing material as a main component, and a heat-sensitive recording magnetic recording medium in which a protective layer is laminated in this order, wherein the aluminum powder as the main component of the hiding layer is
A heat-sensitive magnetic recording medium, which is treated with at least one of a silane-based, titanate-based, and aluminum-based coupling agent. 2. The heat-sensitive recording magnetic recording medium according to claim 1, wherein the aluminum powder is one obtained by removing a fatty acid which is a grinding aid. 3. The heat-sensitive recording type magnetic recording medium according to claim 1, wherein a heat-sensitive recording layer and a protective layer are laminated in this order on the other surface of the base material.