JP3353153B2 - Thermal magnetic recording media - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermosensitive magnetic recording medium useful for, for example, a ticket, a coupon, a commuter pass, and the like.

[0002]

2. Description of the Related Art In recent years, in travel and commuting, users of tickets, coupons, commuter passes and the like have been increasing, and in particular, JNR, private railways,
The increase is remarkable in the Tokyo metropolitan area and the Osaka metropolitan area where urban transportation networks such as subways are well developed. For this reason, the number of people and the time required to create these tickets, coupons, commuter tickets, etc., and the time have increased dramatically. Has been put to practical use.

[0003] As conventional print recording methods for tickets and the like, an electrophotographic method, an electrostatic recording method, a diazo copying method using a two-component chemical reaction, a chelating method, and a printing method using ink have been used. However, when these conventional recording methods are used in a vending machine, development and fixing processes are required, which makes the printing mechanism of the vending machine complicated and large, and the size of the machine body in which it is built becomes large and costly. In the case of the method using the printing method, there is a drawback that the semi-dry ink adheres to the hand because the ink is used, and the clothes are stained. Further, vending machines generally use high-quality paper as a support for the above-mentioned tickets, and therefore have the drawback that if the support gets wet, it will break or wrinkle, and the operation of the machinery will stop.

In recent years, high-density recording has been required for magnetic recording media, and it has been considered to reduce the particle size of γ-ferrite powder, use of reduced powder (metal powder), and the like. It is no exaggeration to say that the technical point of producing such a high-density magnetic recording medium relates to how these fine powders are dispersed in a binder resin. For this reason, a great deal of labor is spent on dispersion, for example, surface modification of magnetic powder, development of various dispersers and dispersion processes,
Various methods have been studied to improve dispersibility, such as adoption of a new dispersant or binder resin. Among them, regarding the magnetic powder dispersion method, a so-called wet dispersion method in which the magnetic powder is dispersed with a dissolver, a kneader, a ball mill, a sand grinder, a vent shaker, or another disperser together with a dispersant or a binder resin in water or an organic solvent, is used. Was adopted.
The reason for this is that needle-like γ-ferrite powder and metal powder, which are used in most applications except for some magnetic cards, are brittle against mechanical stress and are easily broken. It is considered that this is particularly liable to be oxidized, and there is a danger of ignition or explosion in a dry state, so that it is necessary to always handle it in a wet state. As described above, in the related art, since the magnetic coating material is prepared by a complicated and cumbersome dispersing means, a problem that the productivity of the magnetic recording medium is low has always been encountered. What is particularly problematic with these magnetic dispersions is that
Pot life as a dispersion becomes an important point,
It has been desired to produce a dispersion which is stable over time, specifically, such that the particle size distribution immediately after dispersion does not change without aggregation over time.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and has as its object to provide a thermosensitive magnetic recording medium having excellent coating uniformity and excellent magnetic properties.

[0006]

According to the present invention, a magnetic recording layer having a magnetic material and a binder as main components is provided on one surface of a support, and the other surface of the support is usually colorless or colorless. In a thermosensitive magnetic recording medium provided with a thermosensitive coloring layer containing, as a coloring component, a slightly light-colored leuco body and an acidic substance capable of reacting with the leuco body to form a color when heated, the styrene-maleic acid monoester copolymer is added to the magnetic recording layer. It is characterized by containing a polymer ammonium salt, and solves the above-mentioned problem by using barium ferrite as a magnetic substance. According to the present invention, the following inventions are provided.
Magnetic body made of barium ferrite on one side of the support
And a magnetic recording layer mainly comprising
Usually colorless or slightly pale leuco on the other side of
And an acidic substance that reacts with the leuco body when heated to form a color.
Thermosensitive magnetic recording provided with a thermosensitive coloring layer containing as a coloring component
In the recording medium, the magnetic recording layer is represented by the following structural formula (1).
Styrene maleate monoester copolymer
Thermosensitive magnetic recording characterized by containing ammonium salt
Recording medium.

Embedded image (In the formula, R represents a lower alkyl group or an aryl group.
n represents 5 to 20. )

Hereinafter, the thermosensitive magnetic recording medium according to the present invention will be further described. As the ammonium salt of styrene maleic acid monoester copolymer contained in the magnetic recording layer, one having the following structural formula (I) is used.

Embedded image (In the formula, R represents a lower alkyl group or an aryl group, and n represents 5 to 20.) In the general formula (I), as the lower alkyl group, a methyl group, an ethyl group, a propyl group, an iso-propyl group, Examples include a butyl group and a tert-butyl group, and examples of the aryl group include a phenyl group, a lower alkyl group, and a phenyl group which may be substituted with halogen. Styrene maleic
Specific examples of the acid monoester copolymer ammonium salt include the following compounds. Ammonium salt of styrene-maleic acid monomethyl ester copolymer,
Ammonium salt of styrene-maleic acid monoethyl ester copolymer, ammonium salt of styrene-maleic acid monopropyl ester copolymer, styrene-maleic acid monoiso-propyl ester copolymer ammonium salt, styrene-monobutyl maleate Ammonium salts of ester copolymers, ammonium salts of styrene-maleic acid mono-p-tolyl ester copolymers, ammonium salts of styrene-maleic acid monophenyl ester copolymer, and the like. In addition, styrene maleic acid monoester copolymer
-As the ammonium salt , the value of n in the above general formula is 5 to 5.
20 are used. Styrene maleate monoe
The amount of the ammonium salt of the stercopolymer is not particularly limited, but is usually 0.1 part by weight or less, preferably 0.01 to 0.5 part by weight, per part by weight of the magnetic material.

This styrene maleic acid monoester copolymer
Although it is not clear how the polymer ammonium salt exerts an effect on the dispersion stability of the magnetic recording layer dispersion liquid, it has a higher surface tension lowering ability than conventional water-soluble polymers, It is presumed that the excellent force (wetting property) acts synergistically to effectively suppress the pot life of the dispersion.

As the magnetic substance, any of the conventionally known magnetic substances can be used.
O.6Fe ₂ O ₃ (barium ferrite) is preferably used. As the binder, conventionally known binders such as polyvinyl alcohol, vinyl chloride resin, and polyurethane resin can be used.

In the present invention, the leuco dye used in the thermosensitive coloring layer is applied alone or as a mixture of two or more.
As such a leuco dye, those applied to this kind of heat-sensitive material are arbitrarily applied, and for example, triphenylmethane-based, fluoran-based, phenothiazine-based, auramine-based, spiropyran-based, indolinophthalide-based and the like A leuco compound of a dye is preferably used. Specific examples of such leuco dyes include, for example, those shown below.

3,3-bis (p-dimethylaminophenyl) -phthalide, 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide (also known as crystal violet lactone), 3,3-bis ( p-dimethylaminophenyl) -6-diethylaminophthalide,
3,3-bis (p-dimethylaminophenyl) -6-chlorophthalide, 3,3-bis (p-dibutylaminophenyl) phthalide, 3-cyclohexylamino-6-chlorofluoran, 3-dimethylamino-5,7 -Dimethylfluoran, 3-N-methyl-N-isobutyl-6-methyl-7-anilinofluoran, 3-N-ethyl-N-
Isoamyl-6-methyl-7-anilinofluoran, 3
-Diethylamino-7-chlorofluoran, 3-diethylamino-7-methylfluoran, 3-diethylamino-7,8-benzfluoran, 3-diethylamino-6
-Methyl-7-chlorofluorane, 3- (Np-tolyl-N-ethylamino) -6-methyl-7-anilinofluoran, 3-pyrrolidino-6-methyl-7-anilinofluoran, 2- {N- (3'-trifluoromethylphenyl) amino} -6-diethylaminofluoran, 2
-{3,6-bis (diethylamino) -9- (o-chloroanilino) xanthyl lactam lactam}, 3-diethylamino-6-methyl-7- (m-trichloromethylanilino) fluoran, 3-diethylamino-7- (O
-Chloroanilino) fluoran, 3-dibutylamino-
7- (o-chloroanilino) fluoran, 3-N-methyl-N-amylamino-6-methyl-7-anilinofluoran, 3-N-methyl-N-cyclohexylamino-
6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7- (2 ′, 4′-dimethylanilino) fluoran, 3 -(N, N-diethylamino) -5-methyl-7- (N, N-dibenzylamino)
Fluoran, benzoyl leucomethylene blue, 6'-
Chloro-8'-methoxy-benzoindolino-spiropyran, 6'-bromo-3'-methoxy-benzoindolino-spiropyran, 3- (2'-hydroxy-4'-dimethylaminophenyl) -3- (2 ' -Methoxy-5 '
-Chlorophenyl) phthalide, 3- (2'-hydroxy-4'-dimethylaminophenyl) -3- (2'-methoxy-5'-nitrophenyl) phthalide, 3- (2'-
(Hydroxy-4'-diethylaminophenyl) -3-
(2′-methoxy-5′-methylphenyl) phthalide,
3- (2'-methoxy-4'-dimethylaminophenyl) -3- (2'-hydroxy-4'-chloro-5'-
Methylphenyl) phthalide, 3-morpholino-7- (N
-Propyl-trifluoromethylanilino) fluoran, 3-pyrrolidino-7-trifluoromethylanilinofluoran, 3-diethylamino-5-chloro-7-
(N-benzyl-trifluoromethylanilino) fluoran, 3-pyrrolidino-7- (di-p-chlorophenyl) methylaminofluoran, 3-diethylamino-5
-Chloro-7- (α-phenylethylamino) fluoran, 3- (N-ethyl-p-toluidino) -7- (α-
Phenylethylamino) fluoran, 3-diethylamino-7- (o-methoxycarbonylphenylamino) fluoran, 3-diethylamino-5-methyl-7- (α
-Phenylethylamino) fluoran, 3-diethylamino-7-piperidinofluoran, 2-chloro-3-
(N-methyltoluidino) -7- (pn-butylanilino) fluoran, 3- (N-methyl-N-isopropylamino) -6-methyl-7-anilinofluoran, 3
-Dibutylamino-6-methyl-7-anilinofluoran, 3,6-bis (dimethylamino) fluorenespiro (9,3 ')-6'-dimethylaminophthalide, 3-
(N-benzyl-N-cyclohexylamino) -5,6
-Benzo-7-α-naphthylamino-4′-bromofluoran, 3-diethylamino-6-chloro-7-anilinofluoran, 3-N-ethyl-N- (2-ethoxypropyl) amino-6 Methyl-7-anilinofluoran, 3-N-ethyl-N-tetrahydrofurfurylamino-6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7-mesitidino-4 ′, 5 ′ −
Benzofluorane, 3- (p-dimethylaminophenyl) -3- {1,1-bis (p-dimethylaminophenyl) ethylene-2-yl} phthalide, 3- (p-dimethylaminophenyl) -3-} 1,1-bis (p-dimethylaminophenyl) ethylene-2-yl} -6-dimethylaminophthalide, 3- (p-dimethylaminophenyl) -3- (1-p-dimethylaminophenyl-1-phenyl Ethylene-2-yl) phthalide, 3- (p-dimethylaminophenyl) -3- (1-p-dimethylaminophenyl-1-p-chlorophenylethylene-2-yl) -6-dimethylaminophthalide, 3- (4′-dimethylamino-2′-methoxy) -3- (1 ″ -p-dimethylaminophenyl-1 ″ -p-chlorophenyl-
1 ″, 3 ″ -butadiene-4 ″ -yl) benzophthalide, 3- (4′-dimethylamino-2′-benzyloxy) -3- (1 ″ -p-dimethylaminophenyl-1 ″ -Phenyl-1 '', 3 ''-butadiene-
4 ″ -yl) benzophthalide, 3-dimethylamino-
6-dimethylamino-fluorene-9-spiro 3 ′
(6′-dimethylamino) phthalide, 3,3-bis ｛2
-(P-dimethylaminophenyl) -2- (p-methoxyphenyl) ethenyl} -4,5,6,7-tetrachlorophthalide, 3-bis {1,1-bis (4-pyrrolidinophenyl) ethylene -2-yl} -5,6-dichloro-
4,7-dibromophthalide, bis (p-dimethylaminostyryl) -1-naphthalenesulfonylmethane, bis (p-dimethylaminostyryl) -1-p-tolylsulfonylmethane and the like.

Examples of the color developing agent used in the thermosensitive coloring layer of the present invention include various electron-accepting compounds which form a color when the leuco dye is contacted, such as phenolic compounds, thiophenolic compounds, thiourea derivatives, and organic compounds. Acids and metal salts thereof are preferably applied, and specific examples thereof include the following.

4,4'-isopropylidenebisphenol, 4,4'-isopropylidenebis (o-methylphenol), 4,4'-secondarybutylidenebisphenol 4,4'-isopropylidenebis (2-tert-butylphenol) ), 4,4'-cyclohexylidenediphenol, 4,4'-isopropylidenebis (2
-Chlorophenol), 2,2'-methylenebis (4-
Methyl-6-tert-butylphenol), 2,
2′-methylenebis (4-ethyl-6-tert-butylphenol), 4,4′-butylidenebis (6-tert-butyl-2-methylphenol), 1,1,
3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,1,3-tris (2
-Methyl-4-hydroxy-5-cyclohexylphenyl) butane, 4,4'-thiobis (6-tert-butyl-2-methylphenol), 4,4'-diphenolsulfone, 4-isopropoxy-4'- Hydroxydiphenylsulfone, 4-benzyloxy-4'-hydroxydiphenylsulfone, 4,4'-diphenolsulfoxide, isopropyl P-hydroxybenzoate, P-
Benzyl hydroxybenzoate, benzyl protocatechuate, stearyl gallate, lauryl gallate, octyl gallate, 1,7-bis (4-hydroxyphenylthio) -3,5-dioxaheptane, 1,5-bis (4-
(Hydroxyphenylthio) -3-oxapentane, 1,
3-bis (4-hydroxyphenylthio) -propane,
1,3-bis (4-hydroxyphenylthio) -2-hydroxypropane, N, N-diphenylthiourea, N,
N'-di (m-chlorophenyl) thiourea, salicylanilide, 5-chloro-salicylanilide, 2-hydroxy-3-naphthoic acid, 2-hydroxy-1-naphthoic acid, 1-hydroxy-2-naphthoic acid, hydroxy Metal salts of naphthoic acid such as zinc, aluminum and calcium;
Bis- (4-hydroxyphenyl) acetic acid methyl ester, bis- (4-hydroxyphenyl) acetic acid benzyl ester, 1,3-bis (4-hydroxycumyl) benzene, 1,4-bis (4-hydroxycumyl) benzene,
2,4′-diphenol sulfone, 3,3′-diallyl-4,4′-diphenol sulfone, α, α-bis (4
-Hydroxyphenyl) -α-methyltoluene, an antipyrine complex of zinc thiocyanate, tetrabromobisphenol A, tetrabromobisphenol S, 4,4′-
Thiobis (2-methylphenol), 4,4′-thiobis (2-chlorophenol) and the like.

Further, in the thermosensitive coloring layer of the present invention, if necessary, together with the leuco dye and the developer,
Auxiliary additives commonly used in this type of heat-sensitive recording material, for example, pigments, heat-fusible substances, surfactants and the like can be used in combination. In this case, as the pigment, for example, calcium carbonate, silica, zinc chloride, titanium oxide, aluminum hydroxide, zinc hydroxide, barium sulfate, clay, talc,
In addition to inorganic fine powders such as calcium and silica surface-treated, organic fine powders such as urea-formalin resin, styrene / methacrylic acid copolymer, and polystyrene resin can be mentioned. Examples of the substance include, in addition to higher fatty acids or their esters, amides or metal salts, various waxes, condensates of aromatic carboxylic acids and amines, benzoic acid phenyl esters, higher linear glycols, 3,4-epoxy- Those having a melting point of about 50 to 200 ° C, such as dialkyl hexahydrophthalate, higher ketones, and other heat-fusible organic compounds, may be mentioned.

Further, in the present invention, if necessary, an under layer may be provided between the support and the thermosensitive coloring layer, and a protective layer may be provided on the thermosensitive coloring layer. Incidentally, as an under layer, a protective layer may contain a pigment, a binder, a heat-fusible substance, and the like.In this case, specific examples of the pigment, the binder, and the heat-fusible substance include the heat-sensitive coloring layer. There may be mentioned the same ones as exemplified.

The heat-sensitive recording material of the present invention is produced, for example, by applying the above-mentioned cloth liquid for forming each layer on a suitable support such as paper, synthetic paper, plastic film and the like, followed by drying. Applied to the field.

[0017]

Next, the present invention will be described in more detail with reference to examples. The parts and percentages shown below are based on weight. (Solution A) 160 parts by weight of water 100 parts by weight of γ-Fe ₂ O ₃ 10 parts by weight of a 30% solution of ammonium styrene maleate copolymer ammonium salt 50 parts by weight of a 10% solution of polyvinyl alcohol 50 parts by weight (Solution B) 160 parts by weight of water part barium ferrite _{(BaO · 6Fe 2 O 3)} 100 parts by weight of a 30% solution 10 parts by weight of polyvinyl 10% alcohol solution 50 parts by weight of styrene-maleic acid monoester copolymer ammonium salt (C solution) water 160 parts by weight of barium ferrite ( BaO.6Fe ₂ O ₃ ) 100 parts by weight 10% solution of polyoxyethylene alkylphenol ether 10 parts by weight 10% solution of polyvinyl alcohol 50 parts by weight (solution D) 160 parts by weight barium ferrite (BaO.6Fe ₂ O ₃ ) 100 parts by weight polyoxypropyl Down - Polyoxyethylene 10% solution 10 parts by weight of polyvinyl alcohol 10% solution 50 parts by weight of the block polymer (F solution) Water 160 parts by weight of γ-Fe ₂ O ₃ 100 parts by weight of the polyvinyl alcohol 10% solution 50 parts by weight of the The mixture having the composition of (A) to (F) is dispersed using a sand grinder such that the median particle size measured by a particle size distribution analyzer LA-700 manufactured by Horiba Seisakusho is about 6 μm, and a dispersion (solution A) is prepared. (F solution) was prepared.

Example 1 Dispersion (Solution A) 100 parts by weight Vinylidene chloride 49% solution 40 parts by weight Polyvinyl alcohol 10% aqueous solution 15 parts by weight An aqueous magnetic coating solution was prepared by mixing and stirring to obtain the above composition. Was provided with an under layer mainly composed of a styrene-butadiene copolymer, and after drying, the weight was 100 g / m 2.
^The resultant was coated and dried to obtain a magnetic recording sheet.

Example 2 A dispersion (B) was used instead of the dispersion (A) in Example 1.
Liquid recording sheet of the invention was obtained in the same manner as in Example 1 except that the liquid was used.

Comparative Example 1 A comparative magnetic recording sheet was obtained in the same manner as in Example 1 except that the dispersion liquid (liquid C) was used instead of the dispersion liquid (liquid A) in Example 1.

Comparative Example 2 A magnetic recording sheet for comparison was obtained in the same manner as in Example 1 except that the dispersion liquid (D liquid) was used in place of the dispersion liquid (A liquid) of Example 1.

Comparative Example 3 A magnetic recording sheet for comparison was obtained in the same manner as in Example 1 except that the dispersion liquid (F liquid) was used in place of the dispersion liquid (A liquid) of Example 1.

Further, a heat-sensitive layer and a protective layer as conventionally known were provided on the back surface of each magnetic recording sheet obtained above to obtain a heat-sensitive magnetic recording sheet. In the thermosensitive magnetic recording sheet thus obtained, the uniformity of the coating of the magnetic layer was evaluated by visual observation and finger sensation, and the magnetic characteristics were evaluated by variations in output waveforms from Shinko Electric ticket vending machines. Further, the aqueous magnetic coating solutions (Solution A) to (Solution F) obtained above were forcibly sheared for one week (using a commercially available stirring motor) and then transferred to a Horiba Seisakusho particle size distribution analyzer LA-700. The aqueous magnetic coating solutions were evaluated for stability over time, and the uniformity and magnetic properties of these aqueous magnetic coating solutions were evaluated in the same manner as described above. Table 1 shows the evaluation results.

[0024]

[Table 1] [Coating uniformity] [Magnetic properties] ◎ Very good ○ No variation in output waveform ○ Good △ Some variation in output waveform △ Somewhat coarse × Some variation in output waveform × Some variation in output waveform

[0025]

From the results shown in Table 1, the water-based magnetic coating composition of the present invention is excellent in pot life and coating uniformity, and the magnetic recording medium obtained by using them has stable magnetic properties without deterioration over time. You can see that.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-249193 (JP, A) JP-A-4-241985 (JP, A) JP-A-4-169279 (JP, A) JP-A-4-199 169276 (JP, A) JP-A-60-143430 (JP, A) JP-A-63-261523 (JP, A) JP-A-2-216612 (JP, A) JP-A-59-9909 (JP, A) JP-A-61-57386 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41M 5/28-5/34 B42D 15/10 501 B42D 15/10 541 G11B 5/702 G11B 5/80

Claims (1)

(57) [Claims] 1. A magnetic recording layer mainly composed of magnetic material made of barium ferrite on one surface of the support and a binder provided, usually colorless on the other surface of the support, or, slightly pale In a thermosensitive magnetic recording medium provided with a thermosensitive coloring layer containing, as a coloring component, a leuco body of formula (I) and an acidic substance capable of reacting with the leuco body to form a color when heated, the magnetic recording layer has the following structure:
A thermosensitive magnetic recording medium containing a styrene maleic acid monoester copolymer ammonium salt represented by Formula (1) . Embedded image (In the formula, R represents a lower alkyl group or an aryl group.
n represents 5 to 20. )