JP4571565B2 - Magnetic recording material - Google Patents

Description

  The present invention relates to a magnetic recording material that can be applied to magnetic cards such as tickets, commuter passes, and pass tickets, prepaid cards, and labels such as POS labels.

In recent years, there has been a remarkable spread of magnetic cards in magnetic coupons, road tickets, commuter passes, prepaid cards and the like. These magnetic cards are required to be able to record, as visible information, a balance display that changes each time a customer uses the card, a card validity period, an issue date, and the like. One such recording means is a thermal transfer system.
As the magnetic cards used in this method, those having a magnetic recording layer on one side of a support such as a plastic sheet or fine paper are generally known. In order to satisfy the demand for image uniformity and the like, improvements such as providing an ink receiving layer on the thermal transfer recording side have been attempted.

When this magnetic recording material is used as a ticket, ticketing is performed by a ticketing machine. At that time, information on the ticketing contents of the ticket is written on the magnetic surface, and then when the user passes the ticket gate, The necessary reading, erasing, writing, etc. are performed.
Of these, recorded information is taken out as a voltage waveform in reading information, but it is necessary to accurately recognize each peak in the voltage waveform, so it originally exists in the part where no signal is written. The reading threshold is provided so that noise (referred to as white noise) or external noise is not recognized as a signal.

However, even if this threshold value is provided, when white noise exceeding the threshold value is generated on the ticket side, the ticket gate recognizes this noise as a signal, and as a result, an error occurs.
When a reading error occurs at the ticket gate, the user cannot pass through the ticket gate, so the station staff tries to pass the ticket again to the ticket gate, opens the ticket gate, and checks whether there is any abnormality on the hardware side, etc. It becomes necessary to deal with. Such a situation is a very heavy load for the user who is rushing to pass and the station side who is busy with the response. Furthermore, if this occurs during a very crowded period such as during a rush hour, it will have a significant effect such that many other users will be blocked from passing. In addition, in consideration of the fact that the peak of the voltage waveform tends to decrease due to the erasing / rewriting operation at the time of ticket deduction, the threshold is set even lower, so reading errors are much more likely to occur. In view of the above, it is required to reduce white noise as much as possible particularly in magnetic recording materials as ticket sheets.

Various proposals have been made to meet the above requirements. For example, in Patent Document 1, a fibrous material obtained by injecting a synthetic resin is formed, and a sheet-like base material having a Beck smoothness of 60 seconds or more is used as a support, thereby providing a magnetic recording material having good magnetic properties. Is obtained. Patent Document 2 discloses that an ionomer resin layer is formed by applying an emulsion of an ionomer resin on a uniaxially stretched polypropylene resin film and drying, and then stretching the uniaxially stretched polypropylene resin film. When used as a support for a magnetic recording body made of a biaxially stretched polypropylene resin film having an ionomer resin layer on the surface by stretching in a direction perpendicular to the direction, the noise level may be reduced.
However, when synthetic resin is used as the support, the magnetic layer provided on the support will certainly improve the surface smoothness, and as a result, the level of white noise due to unevenness will be reduced. On the other hand, when such a support is provided with a magnetic layer by a coating method, since the penetration of the magnetic coating liquid is poor, the ratio of the resin on the surface of the magnetic layer is high, and after printing the tint block There is a drawback in that a problem of blocking (a surface opposite to the magnetic surface sticks) is likely to occur when a wound product is obtained. Furthermore, the cost for the support is also higher than when the base paper is used.
As a method for reducing noise, it has been proposed to provide another layer between the magnetic recording layer and the support. For example, in Patent Document 3, a paper support is magnetically formed on an undercoat layer formed of a plastic pigment, a binder resin composed of a water-soluble resin and / or a water-dispersible resin, and a water-based coating agent containing as a main component. When a recording layer is provided, a magnetic recording medium having a small fluctuation rate of reading output when reading magnetic recording and a low DC noise level is obtained.
In Patent Document 4, magnetic properties are also improved by providing a styrene / butadiene latex layer having a gel content of 5 to 75% as the undercoat layer.
Further, Patent Document 5 uses a polyamide resin or a polyamide ester resin containing a polymerized fatty acid as a monomer unit in the undercoat layer. However, these also have an insufficient noise reduction effect, and are not directly applied to the base paper of the support. Compared with the case where a recording layer is provided, the magnetic liquid is less likely to penetrate into the undercoat layer, so that a blocking problem is likely to occur.
As another directionality, in Patent Document 6, coated paper is used on the magnetic surface side as a support, and the Parker print surf smoothness (PPS) at a pressure of 10 kg / cm ² on the magnetic layer surface is set to 3.8 μm or less. However, the coated paper has low adhesion between the coated layer and the underlying paper, so that the magnetic layer can be easily formed with tape or the like when the final product is used. It has a problem that it is easy to peel off.

Japanese Patent Laid-Open No. 06-135138 JP 04-248117 A Japanese Patent Laid-Open No. 04-252418 Japanese Patent Laid-Open No. 04-043094 JP 2003-346324 A JP 04-249193 A

  An object of the present invention has been made in view of the above circumstances, and achieves a reduction in white noise that has been demanded in recent years, and has a well-balanced magnetic recording material that does not cause a contradiction such as blocking or peeling of a magnetic layer. Is to provide.

As a result of intensive studies to solve these problems, the present inventors have significantly reduced the level of white noise by using a support having a formation index of 90% or more, and are a magnetic recording material in which blocking and magnetic layer do not peel off. It was found that can be obtained. That is,
In the first aspect of the present invention, in a magnetic recording material in which a magnetic recording layer mainly comprising a ferromagnetic powder and an aqueous binder is provided on one surface of a support, the base index of the base paper used as the support is 90%. The magnetic recording material is characterized in that the smoothness of the surface on which the magnetic recording layer of the support is provided is 60 seconds or more and the ash content of the support is 2% or less .
The second invention relates to a magnetic recording material of claim 1, bulk density of the support is characterized in that 0.85 or less.
A third aspect of the present invention relates to the magnetic recording material according to claim 1 or 2 , wherein the whiteness of the support is 80% or more.
According to a fourth aspect of the present invention, there is provided a heat-sensitive recording layer containing an electron-donating colorless or light-colored leuco dye and an electron-accepting developer on the other surface of the support which is not provided with a magnetic recording layer. it is provided a magnetic recording material according to any one of claims 1 to 3, characterized in.
According to a fifth aspect of the present invention, a thermal transfer ink receiving layer mainly comprising a pigment and a binder is provided on the other surface of the support on which the magnetic recording layer is not provided. 4. The magnetic recording material according to any one of 4 above.

Hereinafter, the magnetic recording material of the present invention will be described in more detail.
The support used for the magnetic recording material of the present invention should have a formation index of 90% or more.
The texture index here is an index indicating how uniformly materials such as fibers and internal additives existing in paper are present, and means that the higher the numerical value, the more uniformly.
The measurement method includes a transmission method or a reflection method using a light source, and the transmittance or reflectance of tens of thousands to hundreds of thousands of points in the measurement range is evaluated as a histogram image, and the degree of variation is displayed as an index. There are various measuring instruments.
The formation index described in the present specification was measured using a 3S sheet analyzer manufactured by MK system Inc., which is one of them.
When a magnetic recording layer is provided on a support having a formation index of less than 90%, the uniformity of the support is not sufficient, so that when the magnetic recording layer is applied, the coating solution permeates the support unevenly.
Normally, after applying the magnetic recording layer and before drying, the magnetic material is oriented, but if the soaking is not uniform, the orientation of the magnetic material in the recording layer is not uniform, and as a result, white noise tends to increase. .

In addition, since the surface smoothness of the magnetic recording layer after drying is low, the physical unevenness increases, and even after the calendar (surface smoothing step) process, the smoothness is insufficient and the white noise is also high. turn into.
On the other hand, when the formation index is 90% or more, since the dispersion of the permeation becomes small when the magnetic recording layer is applied, the orientation of the magnetic material becomes uniform, and the white noise is remarkably reduced. Further, since the physical unevenness is reduced, the smoothness after the calendar process is also improved, and the white noise is further reduced because the adhesion with the magnetic head is improved.
Further, if the surface of the support on which the magnetic recording layer is provided has a smoothness of 60 seconds or more, the surface becomes even more smooth after the magnetic recording layer is provided, and noise is reduced.
Furthermore, when the ash content of the support is 2% or less, the ratio of the internal additive, which is a relatively hard material, decreases, so the load on the cutter in the ticketing machine is reduced and the life of the cutter is extended. Maintenance is improved. Further, when the tension of the support [the basis weight of the support (= weight per unit area) divided by the thickness of the support] is 0.85 or less, the smoothing of the calendar after coating the magnetic recording layer In the process, the smoothness of the surface of the magnetic recording layer tends to be high, and the white noise is also reduced.
When the whiteness of the support is 80% or more, a high-contrast after copy-forgery-inhibited pattern printing applied as a voucher is obtained, a clear printed image can be obtained with a small amount of ink, and a magnetic recording material with good workability can be obtained. It is done.

As the base paper used as the support used in the present invention, natural pulp paper composed mainly of wood pulp mixed with conifers, hardwoods, conifers, and hardwoods is used.
Coniferous trees include red pine, black pine, todomatsu, spruce, fir, tsuga, cedar, cypress, larch, syringe, spruce, hiba, merck pine, radiata pine, red pine, pine, cedar, spruce and white fur. Examples of broad-leaved trees include hippopotamus, beech, alder, oak, tub, shii, birch, boxwood, poplar, tamo, dragonfly, eucalyptus, mangrove, and lauan. used.
Specifically, the mixing ratio of long-fiber conifer pulp and short-fiber hardwood pulp is preferably in the range of conifer / hardwood (weight ratio) = 5/95 to 20/80.
The paper support made with the mixing ratio is low in density and excellent in rigidity and smoothness.
In addition to sizing agents such as talc and calcium carbonate, synthetic resins, rosin, starch, etc., wet strength improvers, softeners, curing agents, yield improvers, antifoaming agents, Gums, water repellents, and the like can be used, and a magnetic recording layer mainly composed of ferromagnetic powder and an aqueous binder is provided on the support.
The preferred basis weight of the support 60~300g / ^{m 2,} more preferably from 100 to 200 g / ^{m 2.}

For the production of paper as a support, a paper machine such as a long net, a round net, or a twin wire can be used, and other methods such as size press and coating can be added as necessary.
Also, the variation in magnetic output is affected by the surface properties of the sheet. Since the flatter one has better adhesion to the magnetic head, it is quite natural that the variation in magnetic output is reduced.
Therefore, a flattening device such as a machine calendar, a gloss calendar, a super calendar, or a brushing can be used after the paper making process or the magnetic layer coating process.

Magnetic recording layer The magnetic recording layer is composed mainly of a ferromagnetic powder and an aqueous binder. In addition, an antifoaming agent, a thickening agent, a curing agent, a penetrating agent, an anti-blocking agent, a water repellent, and a water-resistant agent In addition, color pigments such as carbon black and additives such as dispersants can be contained.
As the magnetic powder, γ ferrite, barium ferrite, strontium ferrite, etc. are used, but barium ferrite and strontium ferrite having a coercive force of 1500 to 5000 oersted are often used so that magnetic recording information is not erased by a normal magnet. . A polyacrylic acid salt or the like can be used for dispersing the magnetic powder.

Aqueous binder resin The aqueous binder resin of the magnetic recording layer includes starches such as oxidized starch and etherified starch, hydroxyethyl cellulose, methyl cellulose, polyvinyl alcohol, polyacrylamide, carboxymethyl cellulose, arabi gum, casein, gelatin, polyethylene oxide, etc. Various latexes such as a water-soluble binder, polyurethane-based, vinyl chloride-based, polyacrylic-based, and styrene-butadiene-based are exemplified, and one or more of these are appropriately selected and used.
Among these, those having a glass transition point (Tg) of 0 to 30 ° C. are preferably used.
When a water-soluble binder having a glass transition point of less than 0 ° C. is used, stickiness occurs in the magnetic recording layer and a blocking phenomenon tends to occur. In addition, when a water-soluble binder having a glass transition point exceeding 30 ° C. is used, the film-forming property of the magnetic recording layer is deteriorated, and the magnetic material is likely to fall off.
The amount of the water-soluble binder used is preferably 35 to 60 parts by weight with respect to 100 parts by weight of the ferromagnetic material. If the amount is less than 35 parts by weight, cracking of the magnetic recording layer tends to occur, and if it exceeds 60 parts by weight, blocking tends to occur.

The surface resistance of the magnetic recording layer is preferably 10 ⁻⁸ to 10 ⁻⁶ Ω. When the surface resistance of the magnetic recording layer is less than 10 ⁻⁸ Ω, the magnetic recording layer is easily charged, and the magnetic recording layer and the recording layer are stuck due to electrostatic charging at the time of ticketing, and ticketing defects are likely to occur.
On the other hand, if it exceeds 10 ⁻⁶ Ω, static electricity generated by friction between the magnetic head and the magnetic recording surface is not charged in the magnetic recording layer, and is charged in the magnetic head, resulting in noise.
Such a decrease in chargeability can be achieved by adding a conductive substance to the magnetic recording layer (carbon black or the like) or making the magnetic recording layer porous. The surface resistance value is a value measured with a High Resistance Meter (manufactured by Hewlett-Packard Japan) in an environment of 23 ° C. and 50%.

  As an apparatus used for coating the magnetic recording layer of the present invention, an air knife coater, a gravure coater, a roll coater, a rod coater, a curtain coater, a die coater, a lip coater, a blade coater, or the like is used. Also, printing methods such as offset and silk screen can be used.

Recording layer On the other hand, a recording layer for displaying various types of information is formed on the surface of the support. Conventional recording methods such as a thermal recording method, a thermal transfer recording method, and an ink jet recording method are used as appropriate. The electrophotographic method and the offset printing method can be selected and used as necessary.
Therefore, in the heat sensitive method, the recording layer is preferably a heat sensitive recording layer containing an electron donating colorless leuco dye and an electron accepting developer, and in the heat transfer method and the ink jet method. In particular, an ink receiving layer capable of receiving ink is preferably provided.

As the leuco dye used in the heat-sensitive recording layer, conventionally known dyes described below can be used singly or as a mixture of two or more thereof. Such leuco dye is not particularly limited, and may be appropriately selected. For example, a leuco compound of a dye such as triphenylmethane, fluorane, phenothiazine, auramine, spiropyran, or indinophthalide is preferably used.
Further, as the developer used in the heat-sensitive recording layer, compounds having various electron-accepting solid acids that develop color upon contact with a leuco dye are used. For example, phenolic compounds, thiophenolic compounds, thiourea derivatives Organic acids and metal salts thereof can be preferably used.

When the leuco dye and the developer are bonded and supported on the support in order to form the heat-sensitive recording layer of the present invention, various conventionally known binders can be appropriately used.
For example, polyvinyl alcohol, starch and derivatives thereof, cellulose derivatives such as hydroxymethylcellulose, hydroxyethylcellulose, carboxymethylcellulose, methylcellulose, ethylcellulose, polyacrylic acid soda, polyvinylpyrrolidone, acrylamide / acrylic acid ester copolymer, acrylamide / acrylic acid ester / In addition to water-soluble polymers such as methacrylic acid terpolymers, styrene-maleic anhydride copolymer alkali salts, isobutylene / maleic anhydride copolymer alkali salts, polyacrylamide, sodium alginate, gelatin and casein, polyacetic acid Vinyl, polyurethane, polyacrylic acid, polyacrylate, vinyl chloride-vinyl acetate copolymer, polybutyl methacrylate, vinyl acetate-ethylene copolymer Examples include latex such as styrene-butadiene copolymer, styrene-butadiene-acrylic copolymer, styrene-acrylic acid ester copolymer, vinyl chloride-ethylene copolymer, vinyl acetate-ethylene-vinyl chloride copolymer. It is done.

  In the present invention, together with the leuco dye and the developer, if necessary, as auxiliary additives conventionally used in this heat-sensitive recording material, for example, fatty acids such as stearic acid, stearic acid amide, palmitic acid as a sensitivity improver Heat fusible substances such as fatty acid amides such as acid amides, fatty acid metals such as zinc stearate, aluminum stearate, and zinc palmitate can be used. In addition, pigments, surfactants, lubricants, pressure coloring inhibitors and the like can be used in combination.

Examples of the pigment include inorganic fine powders such as calcium carbonate, silica, zinc oxide, titanium oxide, aluminum hydroxide, zinc hydroxide, barium sulfate, clay, kaolin, talc, surface-treated calcium and silica, Examples thereof include organic fine powders such as urea-formalin resin, styrene-methacrylic acid copolymer, styrene resin, and vinylidene chloride resin. Of these, calcium carbonate, clay, talc, urea-formalin resin, finely divided silica, and the like are preferably used from the viewpoint of oil absorption, sticking, thermal head wear resistance, and the like.
Examples of the lubricant include higher fatty acids and metal salts thereof, higher fatty acid amides, higher fatty acid esters, animal, vegetable, mineral or petroleum-based waxes.

  On the thermosensitive recording layer of the present invention, a protective layer can be provided on the thermosensitive coloring layer for the purpose of improving the storage stability of the recorded image or improving the writing property to the recording material. In this case, as the component constituting the protective layer, the above-described pigments, binders (binders), heat-soluble substances and the like can be used. If necessary, an intermediate layer may be provided between the support and the heat-sensitive recording layer.

As a thermal transfer ink receiving layer containing a pigment and a binder in a thermal transfer system, and as an ink receiving layer containing a pigment and a binder in an inkjet system, the pigment or binder is a pigment used to form the above-described thermal recording layer. And can be used by appropriately selecting from binders.
The thermal transfer ink receiving layer can contain formaldehyde, glyoxazal, melamine, melamine-formaldehyde resin, etc. as a water-proofing agent.
If necessary, additives such as lubricants such as higher fatty acid metal salts and paraffin wax, dispersants, antifoaming agents and the like can be contained. If necessary, an intermediate layer may be provided between the support and the thermal transfer ink receiving layer.
In addition to this, fluorescent whitening agents, surfactants, and the like can be added, and further, the image density can be improved by treating the surface of the ink receiving layer with a calendar or the like for 300 seconds or more. it can.

  According to the present invention, it is possible to provide a magnetic recording material that achieves a reduction in white noise and has a well-balanced quality that does not cause a contradiction such as blocking or peeling of the magnetic recording layer.

EXAMPLES Hereinafter, although an Example , a reference example, and a comparative example are given and this invention is demonstrated concretely, this invention is not limited at all by these Examples.
In addition, the part in an Example , a reference example, and a comparative example represents a weight part.

Preparation of barium ferrite dispersion A (solid content 50%)
Barium ferrite (retention force: 2700 Oe, average particle size: 0.6 μm) 100 parts sodium polyacrylate (20% solids aqueous solution) 10 parts carbon black (38% solids dispersion) 20 parts water 90 parts From the above composition The resulting solution was dispersed with a sand glider for 24 hours to prepare a barium ferrite dispersion A solution. Subsequently, blend with the following emulsion.

B liquid:
Liquid A (50% solids dispersion) 200 parts acrylic emulsion (solids 40%) 150 parts water 50 parts or more of liquids were mixed and stirred to prepare a magnetic recording layer coating liquid (liquid B).

C liquid:
Silica (oil absorption 150 ml / 100 g) 15 parts polyvinyl alcohol 10% aqueous solution 15 parts water 70 parts A mixture of the above composition was dispersed for 15 minutes using a sand mill to prepare solution C. Then, it mixes with the following polyvinyl alcohol.

D liquid:
Liquid C 100 parts Polyvinyl alcohol 10% aqueous solution 50 parts Water 50 parts The above liquids were mixed and stirred to prepare a thermal transfer ink receiving layer coating liquid (liquid D).

Liquid E:
Acrylic plastic filler (particle size 1 μm solid content 25%) 40 parts polyvinyl alcohol 10% aqueous solution 10 parts styrene butadiene latex (solid content 40%) 10 parts water 40 parts The above solution is mixed and stirred to undercoat layer coating solution (E solution) was prepared.

F liquid:
3- (N-dibutyl) amino-6-methyl-7-anilinofluorane 20 parts Polyvinyl alcohol 10% aqueous solution 20 parts water 60 parts A mixture of the above composition is mixed with a sand mill so that the average particle size is 2 μm or less. A liquid F was prepared by dispersion.

G liquid:
4-hydroxy-4'-isopropoxydiphenylsulfone 7.5 parts silica 7.5 parts bis (4-methylbenzyl) oxalate 5 parts polyvinyl alcohol 10% aqueous solution 20 parts water 60 parts A G liquid was prepared by dispersing using a sand mill so that the diameter was 2 μm or less.

Liquid H:
Liquid F 7 parts G liquid 56 parts Water 37 parts The mixture having the above composition was mixed and stirred to prepare a heat-sensitive recording layer coating liquid (H liquid).

Liquid I:
Liquid C 25 parts Polyvinyl alcohol 10% aqueous solution 34 parts Zinc stearate dispersion (solid content 30%) 2 parts Water 39 parts A mixture of the above composition is mixed and stirred to form a protective layer coating liquid for the thermosensitive recording layer (I Liquid).

Reference example 1
170 g basis weight with a texture index of 93%, smoothness on the side where the magnetic recording layer is provided, 45 seconds, ash content of 4%, tension of 0.90, whiteness of 75%, and surface resistance of 10 ⁻⁸ Ω Using a base paper of / m ² as a support, a magnetic recording layer coating solution (liquid B) is applied so that the dry weight is 50 g / m ² , oriented with a face orientation machine with a central magnetic field of 5000 G, and then dried with a drier. And a magnetic recording layer was provided.

Reference Example 2
In the support described in Reference Example 1, a magnetic recording layer was provided in the same procedure as in Reference Example 1 using a base paper having an equivalent basis weight having a smoothness of 60 seconds on the side where the magnetic recording layer was provided as a support.

Reference example 3
A magnetic recording layer was provided on the base paper having the ash content of 1.2% described in Reference Example 2 in the same procedure as in Reference Example 1.

Reference example 4
A magnetic recording layer was provided in the same procedure as in Reference Example 1 on the base paper in which the support described in Reference Example 3 had a tension of 0.85.

Example 1
A magnetic recording layer was provided in the same manner as in Reference Example 1 on the base paper in which the whiteness of the support described in Reference Example 4 was 82%.

Example 2
A magnetic recording layer was provided on the base paper having a surface resistance of 10 ⁻⁶ Ω as described in Example 1 in the same procedure as in Reference Example 1.

Example 3
On the surface opposite to the magnetic recording layer of the magnetic recording material described in Example 2 , the thermal recording layer coating liquid (liquid H) was applied and dried to a weight of 4 g / m ² after drying, and the thermal recording layer was dried. Then, a protective layer coating liquid (I liquid) was applied on the heat-sensitive recording layer so that the dry weight was 3 g / m ² and dried to provide a protective layer.

Example 4
The surface of the magnetic recording material described in Example 2 opposite to the magnetic recording layer was coated with a thermal transfer ink-receiving layer coating liquid (D liquid) and dried so as to have a weight of 8.0 g / m ² . .

Comparative Example 1
Using a polypropylene resin film as a support, a magnetic recording layer was provided on one surface in the same procedure as in Reference Example 1.

Comparative Example 2
170 g basis weight with a ground index of 65%, smoothness on the side where the magnetic recording layer is provided, 40 seconds, ash content of 4%, tightness of 0.92, whiteness of 75% and surface resistance of 10 ⁻⁸ Ω A base paper of / m ² was used as a support, and the undercoat liquid (E liquid) on the support was applied and dried so as to have a weight of 8 g / m ² after drying to provide an undercoat layer. Further, a magnetic recording layer was provided on the undercoat layer by the same procedure as in Reference Example 1.

Comparative Example 3
The formation index is 62%, the smoothness on the side where the magnetic recording layer is provided is 120 seconds, the ash content is 5%, the tightness is 0.92, the whiteness is 78%, the surface resistance is 10 ⁻⁸ Ω, and the coat A magnetic recording layer was provided on a base paper having a basis weight of 170 g / m ^{2 in} the same manner as in Reference Example 1.

Comparative Example 4
A magnetic recording layer was provided on the support described in Comparative Example 2 in the same procedure as in Reference Example 1.

Comparative Example 5
After providing the magnetic recording layer on the support described in Comparative Example 2 in the same procedure as in Reference Example 1, after drying the thermal recording layer coating liquid (H liquid) on the surface opposite to the magnetic recording layer The thermosensitive recording layer was provided by coating and drying so that the weight was 4 g / m ² . Further, a protective layer coating liquid (I liquid) was applied on the heat-sensitive recording layer so as to have a dry weight of 3 g / m ² and dried to provide a protective layer.

Comparative Example 6
After providing the magnetic recording layer on the support described in Comparative Example 2 in the same procedure as in Reference Example 1, the thermal transfer ink receiving layer coating liquid (D After drying, the solution was applied and dried so as to have a weight of 8.0 g / m ² .

Comparative Example 7
A magnetic recording layer was provided on the same support as in Comparative Example 2 by the same procedure as in Reference Example 1 except that the formation index was 86%.

Comparative Example 8
After providing the magnetic recording layer on the support described in Comparative Example 7 in the same procedure as in Reference Example 1, after drying the thermal recording layer coating liquid (H liquid) on the surface opposite to the magnetic recording layer The thermosensitive recording layer was provided by coating and drying so that the weight was 4 g / m ² . Further, a protective layer coating liquid (I liquid) was applied on the heat-sensitive recording layer so as to have a dry weight of 3 g / m ² and dried to provide a protective layer.

Comparative Example 9
After providing a magnetic recording layer on the support described in Comparative Example 7 in the same procedure as in Reference Example 1, a thermal transfer ink receiving layer coating solution (D After drying, the solution was applied and dried so as to have a weight of 8.0 g / m ² .
The samples of Examples 1 to 4, Reference Examples 1 to 4 and Comparative Examples 1 to 5 described above were smoothed by applying a predetermined coating layer and then passing 3 times with a nip pressure of 30 kgf by a mini calender device. did.

The following evaluation was performed on the magnetic recording materials of Examples and Comparative Examples obtained as described above.
The results are shown in Table 1.
< Smoothness >
According to JISP-8119 Beck smoothness test.
<White noise>
Measuring instrument: EMMC-5, magnetic card evaluation tester manufactured by San-Etec
8oki Memory Hicoder made by Hioki Electric Co., Ltd. Cut a sample on which no magnetic signal has been written into a predetermined sheet size (57.5mm ± 0.5mm, 85.0mm ± 0.5mm, measuring direction is long), 1m Insert into a magnetic card testing machine at a speed of / s and measure the noise waveform.
The maximum peak voltage and the minimum peak voltage are extracted with the memory high coder based on the center of the waveform.
A value obtained by dividing the larger absolute value of the two peak voltages by 9.6 is defined as white noise.
White noise (%) = absolute value of peak voltage / 9.6

<Blocking property>
Print layer: (Create printing ink)
Titanium oxide (average particle size 0.20 μm, oil absorption 20 cc / 100 g) 100 parts nitrified cotton [nitrification degree 12.2%, viscosity 6.0 (JISK-6703)
Solid content 50%, IPA impregnation] 20 parts green pigment (malachite green) 3 parts ethyl acetate 150 parts toluene 150 parts In this printing ink, a gravure printing machine was used to provide a printing layer having a thickness of 1.0 μm.
After printing, the printed surface and the magnetic surface were superposed and pressed (200 gf / cm ² ) for 24 hours.
The superimposed surface was peeled off with a finger, and the transfer of the printed layer onto the magnetic surface was observed.
How to evaluate
A: No printing layer transferred.
○: Although there is a slight transfer of the printed layer, it is difficult to confirm visually.
Δ: There is a slight transfer of the printed layer.
X: The transfer of the printing layer can be clearly confirmed.

<Magnetic layer peeling>
After pasting Nichibansello tape (registered trademark) on the magnetic layer, rub the pasting part with 10 reciprocating fingers.
After that, with the sample fixed, pull the tape quickly in the direction of 180 degrees and observe the presence or absence of layer peeling.
○: No peeling
×: There is a layer peeling

<Cutter wear resistance>
Using a commercially available cutter, cut continuously 1000 times in the width direction (length 57.5 mm), and the blade after cutting is observed with a microscope.
A: No blade wear.
○: Slightly worn.
Δ: Evidently worn.
X: The degree of wear is extremely large.

<Print quality>
In the printed sample prepared in the <blocking property> evaluation, the contrast between the printed part and the non-printed part opposite to the magnetic recording layer is visually evaluated.
Rank 5: Very high contrast.
Rank 4: High contrast.
Rank 3: Normal contrast (Comparative Examples 4 and 5 are defined as Rank 3)
Rank 2: The contrast is low and the printed part is clarified.
Rank 1: The contrast is very low and the printed part is not clear.

<Stickness>
The surface and the back surface of the sample are combined at 20 ° C.-20%, and a pressure of 9.2 ± 0.1 kPa is applied, and a distance of 10 cm is rubbed back and forth 10 times at a speed of 20 cm / sec.
A: There is no sticking between the samples.
○: There is almost no sticking.
Δ: Some sticking.
×: Must not be completely attached.

<Dynamic concentration>
In the following method, when the heat sensitive layer is provided on the opposite side of the magnetic recording layer and when the ink receiving layer is provided, the print quality is evaluated as a density value (the higher the density value, the better the printing is).
DT simulator evaluation (printing evaluation of thermal recording layer)
Using a TH-PMD type simulator (manufactured by Matsushita 01D05 type thermal head) manufactured by Okura Electric Co., Ltd., a concentration value under an energy condition of a pulse width of 0.70 ms (= 0.29 mj / dot) was measured with a Macbeth densitometer RD-914.
TTR printer evaluation (printing evaluation of ink receiving layer)
Printing was performed with a ZEBRA140XiIII printer at a printing speed of 100 mm / s and energy setting-3 (standard value ± 0), and the density of the solid printing part was measured with a Macbeth densitometer RD-914.

As a result, the following matters became clear.
1. When the reference example 1 and the comparative examples 1 and 2 are compared, when the base index of the base paper as the support is 90% or more, the white noise level compared to the case of providing the resin film or the undercoat layer as the conventional technology Is low and excellent in blocking and sticking properties.
Further, in comparison with Comparative Example 3 which is another prior art, not only the level of white noise is low, but also the magnetic layer does not peel off.
Further, in comparison with Comparative Examples 4 and 7, the white noise reduction effect when the formation index is 90% or more is clear.
2. When the reference example 1 and the reference example 2 are compared, the smoothness of the magnetic layer is increased. As a result, the white noise is reduced by 0.3%, and the smoothness effect of the base paper is obtained.
3. When the reference example 2 and the reference example 3 are compared, the cutter wear is improved, and the effect of low ash content (= low internal additive) appears.
4). When the reference example 3 and the reference example 4 are compared, the effect of high smoothing appears due to the tightness being 0.85 or less, and the noise is further reduced.
5). When Example 1 and Example 2 are compared, the contrast is improved because the whiteness is 80% or more.
6). When Example 2 and Example 3 were compared, the surface resistance value of the support decreased, making it difficult to be charged, and the sticking property under low humidity was improved.
7). When Example 3 and Comparative Examples 5 and 8 are compared, the print density is high even when the thermal recording layer is provided due to the high base sheet index of the base paper, and the quality superiority is clearly recognized.
8). When Example 4 and Comparative Examples 6 and 9 were compared, the print density was high even when the ink receiving layer was provided due to the high base sheet index of the base paper, and apparently superior quality.

Claims (5)

In a magnetic recording material in which a magnetic recording layer mainly comprising a ferromagnetic powder and an aqueous binder is provided on one surface of a support, the base index of the base paper used as the support is 90% or more , and the support A magnetic recording material, wherein the surface on which the magnetic recording layer is provided has a smoothness of 60 seconds or more and an ash content of the support of 2% or less . The magnetic recording material according to claim 1 , wherein the support has a tension of 0.85 or less. Magnetic recording material according to claim 1 or 2, wherein the whiteness of the support is 80% or more. A heat-sensitive recording layer containing an electron-donating colorless or light leuco dye and an electron-accepting developer is provided on the other surface of the support which is not provided with a magnetic recording layer. magnetic recording material according to any one of claims 1 to 3,. On the other surface which is not provided with the magnetic recording layer of the support, according to any one of claims 1 to 4, characterized in that the thermal transfer ink-receiving layer mainly composed of pigment and binder is provided Magnetic recording material.