JP2008165841A - Optical recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tape-shaped optical recording medium with less dropout. <P>SOLUTION: The tape-shaped optical recording medium wherein information are recorded and reproduced by irradiating a recording layer with a laser beam via a polymer base body has the recording layer composed of an optical recording material, a reflection layer composed of metal or a metal alloy and an antistatic layer formed by dispersing carbon black in a resin in this order on one principal surface of the polymer base body. The antistatic layer has 3.0 to 15.0 nm centerline average surface roughness and 1×10<SP>4</SP>to 1×10<SP>8</SP>Ω/sq surface electric resistance. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a tape-shaped optical recording medium.

As an optical recording medium for recording and reproducing information by laser light irradiation, there are a wide variety of disk-shaped recording media such as a digital audio disk (so-called compact disk) and an optical data disk (so-called digital versatile disk). It is popular.
In order to increase the recording capacity in the general-purpose disc-shaped optical recording medium as described above, it is necessary to increase the size of the disc itself or to increase the recording density. There is a problem that it is easy to invite. In view of this, a tape-like optical recording medium capable of taking a large recording area is being studied as the shape of the recording medium, instead of a disk. For example, a tape-shaped optical recording medium in which a recording layer is provided on one surface of a polymer substrate and a backcoat layer is provided on the other surface has been proposed (Patent Documents 1 and 2).

However, in such a tape-shaped optical recording medium, since the recording layer is disposed close to the laser beam incident surface on the optical recording medium, the incident surface is irradiated with a laser beam that is narrowed to some extent. As a result, unlike a disk-shaped optical recording medium using a thick substrate, the tape-shaped optical recording medium is easily affected by dust such as dust on the surface of the tape, and the error rate is likely to increase. For this reason, for example, a tape-shaped optical recording medium is proposed in which a recording layer and a protective layer are provided on one main surface of a polymer substrate, and recording / reproduction is performed via the polymer substrate (from the substrate side) (patent) Reference 3).
JP-A-5-242523 JP 2004-118960 A Japanese Patent Laid-Open No. 2-218031

  By the way, since the optical recording medium uses reflected light from the recording layer at the time of recording and reproducing information, the medium needs to have a high reflectivity, so that the recording layer is opposite to the laser beam incident side. A thin reflective layer may be laminated.

  However, the reflection layer as described above has a very smooth surface property because a thin layer made of a metal or metal alloy is formed by sputtering or vapor deposition. For this reason, in a tape-shaped optical recording medium in which a recording layer is irradiated with laser light through a polymer substrate, the side on which the recording layer is formed is located on the tape guide side, so that such a reflective layer is the outermost layer. If so, the frictional resistance increases when sliding with a traveling system member such as a guide pin, tape scraping occurs, and dust tends to adhere to the surface. Particularly, a large capacity backup tape such as a computer tape employs a linear recording system in which the tape is run at a high speed so as to realize a higher data transfer speed. For this reason, the frictional resistance on the surface on the recording layer side is likely to increase, and tape scraping and dust adhesion become prominent. Therefore, when a tape-shaped optical recording medium having a reflective layer as described above is applied to such a recording method, even if the recording layer is irradiated with laser light through a polymer substrate, the error rate is sufficiently high. It cannot be reduced and the dropout increases. Then, since the tape is wound around the reel in a state where the dust is attached, the embossment of the unevenness is transferred to the opposite polymer substrate surface by the unevenness of the dust, thereby reducing the transmittance of the laser beam, In addition, the dropout will increase.

  The present invention has been made to solve the above-described problems, and has a dropout characteristic of a tape-like optical recording medium in which information is recorded and reproduced by irradiating a recording layer with laser light through a polymer substrate. The purpose is to improve.

  As a result of intensive studies on the tape-shaped optical recording medium, the present inventors have found that the above-mentioned object can be achieved by making the configuration of the tape-shaped optical recording medium as follows, and have made the present invention.

That is, the present invention is a tape-like optical recording medium on which information is recorded and reproduced by irradiating a recording layer with laser light through a polymer substrate, on one main surface of the polymer substrate. A recording layer made of an optical recording material, a reflective layer made of a metal or a metal alloy, and an antistatic layer in which carbon black is dispersed in a resin in this order, and the centerline average surface roughness of the antistatic layer Is a tape-shaped optical recording medium having a surface electrical resistance of 1 × 10 ⁴ to 1 × 10 ⁸ Ω / sq.

  According to the above configuration, the recording layer made of an optical recording material, the reflective layer made of a metal or a metal alloy, and the antistatic layer in which carbon black is dispersed in the resin are arranged in this order on one main surface of the polymer substrate. In addition to being formed, the antistatic layer has a certain range of surface roughness and surface electrical resistance, so even if a reflective layer made of a smooth metal or metal alloy with a surface property is formed, it is positioned in the outermost layer. The antistatic layer having a moderately rough surface property can lower the coefficient of friction and suppress the charging property of the tape surface than the antistatic layer having a low surface electric resistance. For this reason, tape scraping during sliding can be reduced, and adhesion of dust to the tape surface can also be suppressed.

  ADVANTAGE OF THE INVENTION According to this invention, the dropout at the time of recording and reproducing | regenerating information can be reduced by irradiating a recording layer of a tape-shaped optical recording medium with a laser beam through a polymer base | substrate.

  FIG. 1 is a cross-sectional view schematically showing an example of a tape-shaped optical recording medium according to an embodiment of the present invention. In the tape-like optical recording medium 1 of the present embodiment, a protective layer 3, a recording layer 4, a reflective layer 5, and an antistatic layer 6 are laminated in order on one main surface of a polymer substrate 2. Note that the protective layer 3 is not necessarily provided. Such a tape-shaped optical recording medium 1 can ensure high reflectivity by forming the reflective layer 5 on the side opposite to the side on which the laser light is incident on the recording layer 4. Since the reflective layer 5 made of an alloy has a very smooth surface (for example, a centerline average surface roughness of about 3 nm), the frictional resistance during running of the tape increases.

  For this reason, in the tape-shaped optical recording medium 1, an antistatic layer 6 in which carbon black is further dispersed in a resin is formed on the reflective layer 5. By forming such an antistatic layer 6, the surface property can be lowered, and thereby the friction coefficient can be lowered. Further, since the antistatic layer 6 contains carbon black, the surface electrical resistance is low, and thereby the charging property is suppressed. For this reason, tape scraping during running of the tape can be reduced, and adhesion of dust can be prevented.

  The surface roughness of the antistatic layer is preferably from 3.0 to 15.0 nm, more preferably from 4.0 to 12.0 nm, in terms of centerline average surface roughness. When the surface roughness is less than 3.0 nm, the surface becomes too smooth, and the frictional resistance increases even if an antistatic layer in which carbon black is dispersed in the resin is provided. On the other hand, when the surface roughness is larger than 15.0 nm, the surface of the antistatic layer becomes too rough, and when the tape-like optical recording medium is wound on a reel, the unevenness is easily transferred to the surface of the opposing polymer substrate. .

The surface electrical resistivity of the antistatic layer is preferably ^{1 × 10 4 ~1 × 10 8} Ω / sq, and more preferably ^{1 × 10 4 ~1 × 10 5} Ω / sq. Since the antistatic layer is imparted with conductivity by carbon black, when the surface electrical resistance is less than 1 × 10 ⁴ Ω / sq, it is necessary to add a large amount of small particle size carbon black having poor dispersibility. Roughness becomes rough. On the other hand, when the surface electrical resistance is higher than 1 × 10 ⁸ Ω / sq, the surface electrical resistance becomes too high and dust tends to adhere.

  As the carbon black used for the antistatic layer, acetylene black, furnace black, thermal black and the like can be used, and among these, it is preferable to use a small particle size carbon black and a large particle size carbon black in combination. By adding a small particle size carbon black, conductivity can be imparted, and an antistatic layer with low surface electrical resistance can be obtained, and by adding a large particle size carbon black, An antistatic layer excellent in surface properties can be obtained while suppressing a decrease in dispersibility due to use. As a particle size of small particle size carbon black, 5-200 nm is preferable and 10-100 nm is more preferable. The particle size of the large particle size carbon black is preferably 200 to 400 nm, and more preferably 200 to 300 nm. When the small particle size carbon black and the large particle size carbon black are used in combination, the content of the large particle size carbon black is preferably 5 to 15% by mass relative to the total of both.

In addition to the above carbon black, other inorganic powders may be added to the antistatic layer in order to control surface electrical resistance and smoothness. Specifically, as such inorganic powder, for example, iron oxide, CrO ₂ , Al ₂ O ₃ , BN, Co oxide, MgO, SiO ₂ , SiC, SiN ₄ , ZrO ₂ , TiO ₂ , TiC, _{ITO (In 2 O 3 -SnO 2} ) , and the like.

Resin used for the antistatic layer includes vinyl chloride resin, vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinyl alcohol copolymer resin, vinyl chloride-vinyl acetate-vinyl alcohol copolymer resin, vinyl chloride. -A combination of a polyurethane resin and at least one selected from vinyl acetate-maleic anhydride copolymer resin, vinyl chloride-hydroxyl group-containing alkyl acrylate copolymer resin, cellulose resin such as nitrocellulose, and the like. Can be mentioned. Among these, in order to reduce the coefficient of friction and improve running performance, it is preferable to use a cellulose resin and a polyurethane resin in combination. The resin content is preferably 40 to 150 parts by mass, more preferably 50 to 120 parts by mass, and even more preferably 60 to 110 parts by mass with respect to 100 parts by mass of the total amount of powders such as carbon black and inorganic powder. Preferably, 70 to 110 parts by mass is most preferable. By setting it as 40 mass parts or more, the intensity | strength of an antistatic layer can be improved, and a friction coefficient can be reduced by setting it as 150 mass parts or less. Moreover, when using together a cellulose resin and a polyurethane-type resin, it is preferable to use 30-70 mass parts of cellulose-type resins, and 20-50 mass parts of polyurethane-type resins. Specific examples of the polyurethane resin include polyester polyurethane resin, polyether polyurethane resin, polyether polyester polyurethane resin, polycarbonate polyurethane resin, and polyester polycarbonate polyurethane resin. The polyurethane resin is preferably a polyurethane resin having a functional group in order to improve the dispersibility of carbon black. As such a functional group, specifically, for example, —COOH, —SO ₃ M, —OSO ₃ M, —P═O (OM) ₃ , —O—P═O (OM) ₂ [these In the formula, M represents a hydrogen atom, an alkali metal base or an amine salt], —OH, —NR′R ″, —N ⁺ R ′ ″ R ″ ″ R ′ ″ ″ [these formulas Among them, R ′, R ″, R ′ ″, R ″ ″, R ′ ″ ″ represent a hydrogen atom or a hydrocarbon group], and an epoxy group. Further, in the case of using two or more kinds of polyurethane resin is preferably match the polarity of the functional groups, it is preferable to use a polyurethane resin having inter alia -SO 3 _M group.

  The antistatic layer is desirably used in combination with the above resin together with a thermosetting cross-linking agent that cross-links the functional group contained in the resin. Specific examples of the crosslinking agent include, for example, tolylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate and the like, reaction products of these isocyanates and those having a plurality of hydroxyl groups such as trimethylolpropane, and the above isocyanate. And various polyisocyanates such as condensation products. The content of these crosslinking agents is preferably 1 to 30 parts by mass, more preferably 5 to 20 parts by mass with respect to 100 parts by mass of the resin.

  In addition, a lubricant may be added to the antistatic layer to reduce the friction coefficient. Specific examples of such a lubricant include liquid lubricants such as various fatty acids, fatty acid esters, fluorocarbons, and silicone oils; and solid lubricants such as graphite and molybdenum disulfide.

  The antistatic layer is prepared by mixing a carbon black, a resin, if necessary, an inorganic powder, a crosslinking agent, and a lubricant together with a solvent by a sand mill or the like, and preparing the dispersion with a gravure coater or the like. It is formed by coating. The thickness of the antistatic layer is not particularly limited, but is preferably 0.2 to 0.8 μm. By setting it to 0.2 μm or more, running stability can be secured, which is preferable. On the other hand, the thickness of 0.8 μm or less is preferable because the total thickness of the tape is reduced and the recording capacity per roll can be increased.

  In the tape-shaped optical recording medium of the present embodiment, a conventionally known transparent flexible polymer material can be used as the polymer substrate. Specifically, for example, films having appropriate strength and smoothness such as polyesters such as polyethylene terephthalate and polyethylene naphthalate used for magnetic tapes, polyamides and polyimides can be mentioned. The thickness of the polymer substrate is preferably 3 to 10 μm. A polymer substrate having a thickness of 3 μm or more can increase the tape strength and improve the reliability, and a polymer substrate having a thickness of 10 μm or less can reduce the volume of the tape. A tape-like optical recording medium having a large recording capacity can be obtained. The surface roughness on the side opposite to the side on which the recording layer or the like of the polymer substrate is provided is preferably from 5.0 to 25.0 nm in terms of centerline average surface roughness. If it is the said range, while transferring the surface unevenness | corrugation of an antistatic layer is suppressed, the irregular reflection when a laser beam injects is prevented, and the reduction of a reflectance can be suppressed.

  As the recording layer, known optical recording materials can be used. Specifically, for example, organic dye-based optical recording materials such as cyanine dyes, phthalocyanine dyes, and azo dyes; Te—Fe—Co, Ge—Te, Ge—Sb—Te, In—Sb—Te, Bi—Ge— Examples thereof include inorganic optical recording materials such as Te. These optical recording materials may be used alone or in combination. Examples of the method for forming the recording layer include conventionally known methods such as coating, vapor deposition, sputtering, and ion plating. The optical recording material may be mixed or combined with a polymer resin. The polymer resin is not particularly limited as long as the optical recording material is not crystallized and dispersed in an amorphous state, and examples thereof include methacrylate resins, vinyl resins, and cellulose resins. The thickness of the recording layer is usually 3 to 20 nm.

  As the reflective layer, a highly reflective metal or metal alloy such as Al, Al alloy, Ag, Ag alloy, Au, and Au alloy can be used. Examples of the method for forming the reflective layer include conventionally known methods such as vapor deposition, sputtering, and ion plating. The thickness of the reflective layer is usually 20 to 150 nm.

A conventionally well-known protective layer material can be used as the protective layer. Specifically, for example, metal oxides such as SiO ₂ , TiO ₂ , Al ₂ O ₃ , ZrO ₂ , SnO ₂ , In ₂ O ₃ , metal oxides, Si ₃ N ₄ , TiN, AlN, ZrN, etc. Metal nitrides, sulfides such as ZnS and In ₂ S ₃ , ZnS—SiO _{2 and the} like. Examples of the method for forming the protective layer include conventionally known methods such as vapor deposition, sputtering, and ion plating. The thickness of the protective layer is usually 10 to 80 nm.

  The tape-shaped optical recording medium of the above embodiment may have other layers in addition to the above layers. For example, another protective layer can be formed between the recording layer and the reflective layer, or a cover layer or the like can be formed on the polymer substrate surface opposite to the recording layer side.

FIG. 2 is a schematic diagram showing a recording / reproducing state of the tape-shaped optical recording medium of the present embodiment. As shown in FIG. 2, the tape-shaped optical recording medium 1 of the present embodiment is configured to record laser light L from the side opposite to the side where the recording layer 4 of the polymer substrate 2 is provided by the objective lens 7 during recording. Information is recorded by irradiating while condensing and causing an optical change in the recording layer 4 via the polymer substrate 2. At the time of reproduction, similarly, laser light L is irradiated onto the recording layer 4 through the polymer substrate 2, and information is reproduced by reading the change in the reflected light.
EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated further more concretely, this invention is not limited to these Examples.

(Example 1)
A low birefringence polyethylene terephthalate film (centerline average surface roughness: 6.0 nm) having a thickness of 9 μm was used as the polymer substrate. On one surface of this film, ZnS—SiO ₂ of 18 nm as a protective layer, GeSbTe of 20 nm as a recording layer, and AlTi (Ti = 3 wt%) of 50 nm as a reflective layer were sequentially formed by sputtering in the usual manner.
Next, a mixture having the following composition is dispersed with a sand mill (residence time: 45 minutes), 15 parts of polyisocyanate is added to prepare a dispersion for an antistatic layer, and after filtration, a gravure is formed on the reflective layer prepared above. It was applied so that the thickness after drying with a coater was 0.5 μm. After forming each layer as described above, the obtained raw fabric was slit into a 1/2 inch width to produce a tape-shaped optical recording medium. In the following description, “part” means “part by mass”.
[Dispersion for antistatic layer]
・ Small particle size carbon black (average particle size: 25 nm) 80 parts ・ Large particle size carbon black (average particle size: 350 nm) 10 parts ・ Nonmagnetic plate-like iron oxide powder (average particle size: 50 nm) 10 parts ・ Nitrocellulose 45 parts ・ Polyurethane resin (containing —SO ₃ Na group) 30 parts ・ 260 parts of cyclohexanone ・ 260 parts of toluene ・ 525 parts of methyl ethyl ketone

(Example 2)
A tape-shaped optical recording medium was prepared in the same manner as in Example 1 except that 30 parts of small particle size carbon black and 4.5 parts of large particle size carbon black were used in the production of the tape-shaped optical recording medium of Example 1. Produced.

(Example 3)
A tape-like optical recording medium was produced in the same manner as in Example 1 except that the residence time was 35 minutes in the production of the tape-like optical recording medium of Example 1.

Example 4
A tape-like optical recording medium was produced in the same manner as in Example 1 except that 90 parts of small particle size carbon black and 10 parts of large particle size carbon black were used in producing the tape-like optical recording medium of Example 1. .

(Comparative Example 1)
A tape-like optical recording medium was produced in the same manner as in Example 1 except that the antistatic layer was not provided in the production of the tape-like optical recording medium of Example 1.
(Comparative Example 2)
The production of the tape-shaped optical recording medium of Example 1 was the same as Example 1 except that 25 parts of small particle size carbon black, 3.5 parts of large particle size carbon black were used and the residence time was 35 minutes. Thus, a tape-shaped optical recording medium was produced.

(Comparative Example 3)
A tape-like optical recording medium was produced in the same manner as in Example 1 except that the residence time was 30 minutes in the production of the tape-like optical recording medium of Example 1.
(Comparative Example 4)
A tape was prepared in the same manner as in Example 1 except that 95 parts of small particle size carbon black, 10 parts of large particle size carbon black were used, and the residence time was 50 minutes in the production of the tape-shaped optical recording medium of Example 1. An optical recording medium was produced.

(Comparative Example 5)
In the production of the tape-shaped optical recording medium of Example 1, the same procedure as in Example 1 was conducted, except that 30 parts of small particle size carbon black, 4.5 parts of large particle size carbon black were used, and the residence time was 60 minutes. Thus, a tape-shaped optical recording medium was produced.
The following evaluation was performed on each tape-shaped optical recording medium manufactured as described above. Table 1 shows these results.

<Surface electrical resistance>
The surface electrical resistance of the antistatic layer was measured according to the method described in “Magnetic Media Technical Manual No. 6 Characteristics and Performance of Magnetic Media” of the Japan Magnetic Media Industry Association (issued in March 1993). A tape-shaped optical recording medium is stretched over the ¼ arc-shaped electrodes facing each other at a distance equal to the tape width so that the antistatic layer is in contact with the electrodes, so that the tension becomes 5 N / mm ^2. A load was applied to both ends of the tape, and the electrical resistance between the electrodes was measured using MULTITIMER E2377A manufactured by HEWLETT PACKARD.

<Surface roughness>
The surface roughness of the antistatic layer was measured using a general-purpose three-dimensional surface structure analyzer NewView 5000 manufactured by ZYGO. The antistatic layer of the tape-shaped optical recording medium was measured at five points by scanning white light interferometry with a 50 × objective lens and 2 × zoom setting at 100 × (measurement field of view 72 μm × 54 μm). The roughness Ra was determined.

<Dropout>
The dropout was measured using the recording / reproducing tester shown in the schematic configuration diagram of FIG. A signal was written to the tape-shaped optical recording medium 1 while rotating the tape-shaped optical recording medium 1 wound around the drum 204 having a diameter of 40 mm by the spindle motor 205 whose rotation was controlled by the motor controller 207 at a peripheral speed of 10 m / min. The signal is written by generating a predetermined signal by the arbitrary waveform generator 201, inputting the signal to the pickup head 203 controlled to move by the servo circuit 206 via the laser driver 202, and applying the focus servo to the laser on the recording layer. The adjustment was performed so that the spot diameter of the light was about 1 μm. The laser power at the time of writing was 10 mW.

  Next, similarly, the spot diameter of the laser beam on the recording layer is adjusted to be about 1 μm, and the reproduction signal is taken into the oscilloscope 210 via the pickup head 203, the signal circuit 208, and the signal processing circuit 209, Signals that were 6 dB or more lower than the average output were counted as dropouts. The laser power during reproduction was 1 mW.

<Friction coefficient>
The friction coefficient was evaluated using a friction coefficient measuring machine shown in FIG. The surface on which the antistatic layer is formed is placed in contact with a ceramics bar (diameter: 7 mmφ, material: Al ₂ O ₃ / TiC, roughness: Ra 70 nm), tape with a load of 50 g and a sliding speed of 0.5 mm / sec. The force F at the time of sliding was measured with a load cell, and the friction coefficient at 1 pass, 100 pass, 500 pass, and 1000 pass was calculated by the following formula.
μ (friction coefficient) = (1 / π) ln (F / 50)

上記表１に示されるように、実施例１〜４のテープ状光記録媒体は、表面粗さが３．０〜１５．０ｎｍの範囲の帯電防止層が設けられているため、低い摩擦係数が得られることが分かる。また、その摩擦係数も１パス目から１０００パス目まで増加が殆ど見られないことから、長期に渡って安定して摩擦係数が低く抑えられることが分かる。さらに、これらのテープ状光記録媒体の帯電防止層は、表面電気抵抗が１×１０^４〜１×１０⁸Ω／ｓｑの範囲にあり、帯電性も抑えられている。このため、テープ削れや塵埃の付着が抑えられ、ドロップアウトの少ないテープ状光記録媒体が得られている。

As shown in Table 1 above, the tape-shaped optical recording media of Examples 1 to 4 are provided with an antistatic layer having a surface roughness in the range of 3.0 to 15.0 nm. You can see that Further, since the friction coefficient hardly increases from the first pass to the 1000th pass, it can be seen that the friction coefficient can be stably kept low over a long period of time. Furthermore, the antistatic layer of these tape-shaped optical recording media has a surface electrical resistance in the range of 1 × 10 ⁴ to 1 × 10 ⁸ Ω / sq, and the charging property is also suppressed. For this reason, tape-shaped optical recording media with reduced dropout and reduced tape scraping and dust adhesion are obtained.

  On the other hand, the tape-shaped optical recording medium of Comparative Example 1 is not provided with an antistatic layer, and the reflective layer constitutes the outermost layer, so that the surface roughness is too smooth and the friction coefficient is from the beginning. The friction coefficient is further increased by sliding. Moreover, although the antistatic layer is provided in the tape-shaped optical recording medium of Comparative Example 2, since the surface electrical resistance is too high, dust tends to adhere. On the other hand, the tape-shaped optical recording medium of Comparative Example 3 has a low friction coefficient because the surface roughness of the antistatic layer is rough, but the polymer substrate on the side opposite to the side where the recording layer is provided with the unevenness of the antistatic layer. It is easy to be transferred to the surface. In the tape-shaped optical recording medium of Comparative Example 4, since a large amount of small particle size carbon black is added in the antistatic layer, the surface electrical resistance is too low and the surface roughness becomes rough. Furthermore, the tape-like optical recording medium of Comparative Example 5 is provided with an antistatic layer, but its surface roughness is too smooth, so the friction coefficient is high from the beginning, and the friction coefficient further increases by sliding. For this reason, dropout increases in any of the tape-shaped optical recording media of the comparative examples.

It is sectional drawing which shows typically an example of the tape-shaped optical recording medium which concerns on embodiment of this invention. It is a schematic diagram which shows the state of recording / reproducing of the tape-shaped optical recording medium which concerns on embodiment of this invention. It is a schematic block diagram which shows the recording / reproducing test machine used for evaluation in the Example. It is a schematic block diagram which shows the friction coefficient measuring machine used for evaluation in the Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tape-like optical recording medium 2 Polymer substrate 3 Protective layer 4 Recording layer 5 Reflective layer 6 Antistatic layer

Claims (1)

A tape-like optical recording medium in which information is recorded and reproduced by irradiating a recording layer with a laser beam through a polymer substrate, comprising an optical recording material on one main surface of the polymer substrate. It has a recording layer, a reflective layer made of a metal or a metal alloy, and an antistatic layer in which carbon black is dispersed in a resin in this order, and the antistatic layer has a center line average surface roughness of 3.0 to A tape-shaped optical recording medium having a surface electric resistance of 1 × 10 ⁴ to 1 × 10 ⁸ Ω / sq at 15.0 nm.

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