JPH0690780B2 - Leader tape for magnetic tape - Google Patents

Description

TECHNICAL FIELD The present invention relates to a leader tape for magnetic tape, and in particular,
The present invention relates to a leader tape suitable for magnetic tapes such as audio cassettes and video cassettes.

(Prior Art) Usually, leader tapes are attached to both ends of the magnetic tape. However, this leader tape has recently been sparked between the head and the magnetic tape to prevent winding disorder, and the magnetic tape manufacturing process. In order to remove dust due to static electricity generated therein, antistatic treatment or coating with an abrasive for cleaning the magnetic head is performed. In addition, there is also one in which a magnetic tape grade (recording time, type of magnetic material, etc.) is printed on the antistatic treatment or the abrasive coating layer. Further, the leader tape is required to have a visible light transmissivity in order to be compatible with a tape deck having a built-in auto-reverse function.

(Problems to be solved by the invention) However, the resin used in various conventional coating agents as described above, when a cleaning abrasive or an antistatic agent is added thereto, has an adhesive property with a base film. And the abrasion resistance is poor, and the abrasive, antistatic agent and resin drop off sharply when coming into contact with or sliding on the magnetic head, which makes it impossible to exert a sufficient cleaning effect and antistatic effect for a long time. It also causes dropouts during recording and playback. In addition, there is a problem such as lack of transparency when used for auto-reverse.

Also, one end of the leader tape is fitted with the hub,
Due to the low friction coefficient of the leader tape, there is an accident in which the mating is lost.

The present inventor, as a result of intensive research to solve the above-mentioned drawbacks of the prior art, a leader tape of a magnetic tape, an antistatic mat surface layer of a specific configuration on a transparent substrate film, The present invention has been completed by finding out that the problem can be solved by providing a printing layer on it.

(Means for Solving Problems) That is, according to the present invention, an abrasive-containing antistatic mat surface having any one of the following constitutions (a) to (c) is provided on at least one surface of a transparent base film. A leader tape for magnetic tape, comprising a layer, and a printed layer having a polyurethane resin as a binder provided in a pattern on the surface of the mat surface layer.

(A) A binder resin layer containing an antistatic-treated abrasive.

(B) A binder resin layer containing an antistatic agent and an abrasive.

(C) A binder resin layer containing an abrasive and an antistatic layer provided thereon.

Next, the present invention will be described in more detail. First, the structure of the leader tape for magnetic tape of the present invention will be described first, and FIGS. 1 and 2 schematically illustrating one embodiment of the leader tape of the present invention will be described. It will be described with reference to FIG.

FIG. 1 shows a leader tape 10 for magnetic tape according to the present invention.
FIG. 2 schematically shows a cross section of one embodiment, and FIG. 2 schematically shows a cross section of another embodiment of the magnetic tape leader tape 10 of the present invention.

As is apparent from FIG. 1, in one embodiment of the magnetic tape leader tape 10 of the present invention, a mat surface layer 2 is formed on at least one surface of a base film 1 and printing is performed on the mat surface layer. Form layer 3.

In another embodiment shown in FIG. 2, the matte surface layer 2 is provided on at least one surface of the base film 1, the antistatic layer 4 is provided thereon, and the printing layer 3 is further provided thereon.

In the first embodiment, the matte surface layer 2 may be a binder resin layer containing an antistatic-treated abrasive, or a binder resin layer containing an antistatic agent and an abrasive.

The printing layer 3 in each of the above embodiments does not cover the entire surface of the matte surface layer 3 but is formed in a pattern and displays the grade and the like of the magnetic tape. Such a printing layer 3 may have a one-layer structure as shown in FIG. 1 or a two-layer structure as shown in FIG.

The present invention has solved the above-mentioned various problems of the conventional leader tape for magnetic tape by the above-mentioned configuration.

Next, the present invention will be described in more detail by explaining the materials and forming method required for constituting the leader tape for magnetic tape of the present invention.

Base film 1 for leader tape for magnetic tape of the present invention
As the base film for a leader tape for a magnetic tape, which is conventionally known, any one can be used as long as it is transparent. Specifically, the thickness is about 12 to 50 μm, and the width is about 3 to. Any of a 20 mm stretched polypropylene film, a stretched polyethylene film, a polycarbonate film, a polyethylene terephthalate film, a polyacetate film and the like can be used.

It is desirable that these substrate films are transparent so as to correspond to a tape deck having a built-in auto-reverse function.

The matte surface layer 2 comprising a binder resin, an abrasive and an antistatic agent, which is the first feature of the magnetic tape leader tape of the present invention, will be described below. As the binder resin used in the present invention, there are conventionally known binder resins. Can be used, for example, polyvinyl chloride resin, vinyl chloride-vinyl acetate copolymer resin, vinyl chloride vinyl acetate-vinyl alcohol copolymer resin,
Polyvinyl butyral resin, vinylidene chloride-acrylonitrile copolymer resin, acrylonitrile-butyl acrylate-2-hydroxymethacrylate copolymer resin, vinyl resin such as hydroxy-modified acrylic resin, acrylic resin, polyester resin, polyamide resin Examples thereof include resins, rubber resins such as acrylonitrile-butadiene copolymer resins, nitrocellulose resins, acetylcellulose resins, polyurethane resins, phenoxy resins, epoxy resins, and mixtures thereof.

Among these binder resins, acrylic polyol-based resin obtained by introducing a hydroxyl group into acrylic resin, vinyl chloride-vinyl acetate copolymer-based resin, polyurethane resin or a mixture thereof, particularly acrylic polyol-based resin and vinyl chloride-vinyl acetate-based resin. Mixture with polymer resin (preferred mixing ratio is 1: 0.1 to 1.5 for the former: the latter)
However, it is particularly suitable for the purpose of the present invention because it has excellent adhesion to the substrate film and good abrasion resistance.

Further, in the binder resin as described above used in the present invention,
By optionally blending a crosslinking agent, it is possible to further improve the adhesion to the base film and the abrasion resistance. The cross-linking agent used for this purpose can be any conventionally known cross-linking agent suitable for each binder resin,
Particularly preferred are polyisocyanates such as tolylene diisocyanate, xylylene diisocyanate and hexamethylene diisocyanate, or 2 of these.
It is a polyisocyanate compound of a monomer or higher.

The abrasive used for the matte surface layer of the leader tape of the present invention has a magnetic head cleaning action, and is, for example, iron oxide, tungsten carbide, silicone carbide, diamond, boron nitride, chromium oxide, aluminum oxide. , An inorganic filler such as goethite, tin oxide, zirconia, boron carbide, titanium oxide, silicon oxide, talc, clay, calcium carbonate, or a ceramic treatment thereof, which may be used alone or as a mixture. Of these, the most preferable one for the purpose of the present invention is surface-treated calcined alumina, which has particularly high hardness and excellent abrasion resistance.

These abrasives may be of any conventionally known shape, but those preferred in the present invention have an average particle size of about 0.5 to 5 μm, and those of less than 0.5 μm are incorporated into the binder resin. Dispersion is poor, and the cleaning performance of the magnetic head is poor. On the other hand, when it exceeds 5 μm, the cleaning property of the magnetic head is good, but the surface roughness of the mat surface layer becomes too large and the abrasive may drop off, which is not preferable.

The amount of such an abrasive used is generally about 5 to 50 parts by weight per 100 parts by weight of the binder resin. If the amount is less than 5 parts by weight, the surface of the matte surface layer becomes too smooth, and It is not preferable because the cleaning property becomes insufficient, and when the amount exceeds 50 parts by weight, the transparency of the obtained leader tape becomes insufficient and the leader tape becomes unsuitable for the auto reverse device.

The antistatic agent used in the present invention is a conventionally known one, for example, a cationic antistatic agent such as a quaternary ammonium salt compound or an imidazoline compound, an alkylsulfuric acid ester compound, an alkylarylsulfonic acid compound, Anionic antistatic agents such as alkyl phosphate ester-based compounds, amphoteric antistatic agents such as betaine-based compounds, sorbitan-based compounds, nonionic antistatic agents such as ester-based compounds, and acrylic ammonium-based compounds having polar groups, Any silane-based polymer antistatic agent or the like can be used. Particularly preferred in the present invention are cationic antistatic agents.

Such an antistatic agent may be attached to or adsorbed on the above-mentioned abrasive before use, or may be simply added to the coating agent for forming the mat surface layer. On a minute basis, it is suitable to use in a ratio of about 0.5 to 20 parts by weight per 100 parts by weight of the binder resin.
If the amount used is less than 0.5 parts by weight, a sufficient antistatic effect is not achieved, while if it exceeds 20 parts by weight, bleeding out to the surface of the mat surface layer is severe, and the resulting leader tape is blocked, It is not preferable because its abrasion resistance is reduced.

In order to form a matte surface layer on at least one side of a substrate film from the above materials for preparing the leader tape for magnetic tape of the present invention, one of the methods is to use the above materials as a suitable organic material. A solvent, that is, an organic solvent capable of dissolving the binder resin and the antistatic agent, the above-mentioned abrasive (or antistatic-treated abrasive), the binder resin and the antistatic agent in the use ratio as described above. It is a method in which the coating agent is added and sufficiently dissolved and dispersed to prepare a coding agent, and the coating agent is applied to at least one surface of the substrate film and dried. In such a method, the solid content of the coating agent to be used is preferably adjusted to about 5 to 30% by weight, and if it is less than about 5% by weight, a matte surface layer having a sufficient thickness cannot be formed. weight%
If it exceeds, the viscosity of the coating agent becomes too high and the workability is deteriorated, which is not preferable.

As a method for coating the base material film with the code agent, a conventionally known method, for example, a roll coating method such as a three-reverse roll or a four-reverse roll, a coating method by printing such as gravure printing, flexo printing, or the like is arbitrarily used. The thickness of the mat surface layer which can be formed is about 0.5 to 10 [mu] m, particularly 2 to 5 [mu] m when dry, which is suitable for the purpose of the present invention.

As another method, a matte-bearing mat surface layer is formed with the above-described coating agent that does not substantially contain an antistatic agent or contains a small amount thereof, and then an antistatic layer is formed on the surface with the antistatic agent. There is a way to do it. In such a method, it is preferable to dissolve or disperse the antistatic agent as described above in water or a suitable organic solvent, and apply and dry by the coating method as described above. The layer formed by such a method May be formed on the matte surface layer as described above, or may be formed on the back surface thereof. It is preferable to use such a separate coating method because it is possible to impart excellent antistatic properties to the leader tape with a small amount of the antistatic agent used, and there is no fear of lowering the abrasion resistance of the leader tape. The amount of the antistatic agent used is preferably about 0.01 to ² g / m ² so that a sufficient antistatic effect can be imparted.

As described above, the antistatic mat surface layer 2 is formed on at least one surface of the substrate film 1. In the present invention, the mat formed as described above is exemplified as shown in FIGS. The printing layer 3 is formed on the surface layer in such an area that the good antistatic property and cleaning property of the mat surface layer are not impaired. The printing layer 3 has the purpose of determining the grade of the magnetic tape, the recording time, and the like, and also has the function of ensuring the fitting between the end of the leader tape and the tape winding hub.

Even in the conventional leader tape, such a printing layer is formed, but the printing layer of the conventional leader tape is
The friction coefficient is low, and as a result, there is a problem that the leader tape is easily displaced at the fitting portion with the hub. The present invention solves such a problem.

As a binder resin of the ink for forming the printing layer 3 for such a purpose, it was found that a polyurethane resin or a mixture of this and another binder resin is suitable.

As the polyurethane resin, the pencil hardness of the coating film is 4H.
It is preferable that it is softer and has a high coefficient of friction on the surface. For example, a relatively high molecular weight, for example, a molecular weight of 1000
The above polyether polyol, or polyester polyol such as polycaprolactone polyol having a molecular weight of about 2000, and non-yellowing polyisocyanate such as aliphatic diisocyanate, NCO / OH is reacted at a ratio of about 0.5 to 0.9. A polyurethane resin in which an isocyanate-terminated polyurethane prepolymer is prepared, and an aliphatic or aromatic dian is added thereto to chain-extend to have a molecular weight of about tens of thousands is preferable. Such a polyurethane resin can be used in the present invention, for example, obtained from Honey Kasei Co., Ltd. under the trade name of Honey ST1600.

That is, by using a polyurethane resin as the binder resin of the ink that forms the printing layer, a printing layer with a high friction coefficient is obtained, and the end portion of the leader tape and the fitting portion of the hub come into close contact with each other and are displaced or separated. The present inventors have found that the end portion of the leader tape can be stably secured in the fitting portion without causing any trouble.

In the present invention, such a printing layer 3 may have a single-layer structure as schematically shown in FIG. 1, but in this case, a polyurethane resin or another binder resin as the binder resin of the printing layer is used. Is preferably used,
Further, as shown schematically in FIG. 2, when the printing layer 3 has a two-layer structure, it is preferable that the upper layer 5 thereof is formed of a polyurethane resin or a mixture of this and another resin.

The other components of the ink used for forming the printing layer 3 and the usage ratio thereof may be conventionally known ones, for example, inorganic pigments such as titanium dioxide, cobalt blue and molybdenum blue, phthalocyanine blue and naphthol red. Organic pigments, other calcium carbonate, talc, alumina,
Various additives such as aluminum powder, graphite and molybdenum disulfide can be optionally used, and the printing method may be a conventionally known one, for example, gravure, offset, gravure offset, silk screen, flexo, etc. The method can be applied. The thickness of the printing layer 3 thus formed is not particularly limited, but for the purpose of the present invention, the total thickness is about 1 to 10 μm, and when the two-layer structure is adopted, the upper layer is about 1 to 5 μm. Is preferred.

(Operation / Effect) According to the present invention as described above, the leader tape of the present invention has excellent antistatic properties and also has excellent abrasion resistance and cleaning property of the mat surface layer by having the above-mentioned constitution. Also, because it is transparent, it is an excellent leader tape for magnetic tape that can also be used for auto-reverse. Further, since the printed layer of the leader tape of the present invention has a high friction property, the leader tape can be secured extremely stably without being disengaged from the fitting portion of the hub during use.

Hereinafter, the present invention will be described in more detail with reference to specific examples. In addition, in the text, "%" or "%" is based on weight.

Example 1 Acrylic polyol (Thermolac U230, manufactured by Soken Chemical Industry Co., Ltd.)
T) and vinyl chloride-vinyl acetate copolymer (VAGH manufactured by Union Carbide Co., Ltd.) 15 parts in 1000 parts of a mixed binder resin, 20 parts of calcined alumina having an average particle size of 1 μm (Fujimi abrasive, # 8000), electrification Polyurethane terephthalate film with a thickness of 25 μm by applying a coating agent (Coating agent for leader tape (B) manufactured by The Inktech Co., Ltd., manufactured by The Inktech Co., Ltd.) by adding 5 parts of the inhibitor Arcard T-50 (Lion Aguzo) by a triple roll method (Toyobo Co., Ltd., E5100) was coated on one side with a dry thickness of 3 to 4 μm. On top of this,
Ink with acrylic resin and naphthol red pigment as vehicle by direct gravure method and ink with polyurethane resin (Honey Kasei, Honey ST1600) and titanium dioxide pigment (SCM Chemicals, RCL472) as vehicle (The Inktech) , LAX (white) was used to print in a pattern, and this was cut into 3.81 mm width to obtain an audio leader tape.

The leader tape thus obtained was loaded into a tape cassette together with a magnetic tape, and even after a 1,000-fold playback-rewind test was performed on the cassette deck, the coating agent did not fall off, the magnetic head had good cleaning properties, and antistatic There was no hindrance to the performance and the auto-reverse function, and the fitting force with the hub was good.

Example 2 100 parts of the same binder resin as in Example 1 was used, and the average particle size was 1 μm.
10 parts of m-calcined alumina (Fujimi Abrasives, # 8000) and 5 parts of micro silica having a particle size of 3 μm (Fuji Silysia Chemical, trade name Sicilia 320) were added,
Polycarbonate film with a thickness of 30 μm (manufactured by Teijin Kasei,
(Panlite) on one side by the three-roll reverse roll method,
When dried, it is coated to a thickness of 4 to 5 μm.
On top of this, add antistatic agent Staticide Concentrate (Analytical Chemical Laboratories) with isopropanol.
It was diluted 100 times and coated by the direct gravure method. The same two color inks as in Example 1 were gravure-printed on this pattern in a pattern form and then slit to a width of 3.81 mm to obtain a leader tape of the present invention.

The obtained leader tape of the present invention has a surface resistivity of 10 ⁹ Ωc.
At m, the total light transmittance was 65%, which did not affect the auto-reverse function. Also, the same reproduction-rewind as in Example 1.
Even after 1000 round trips, the abrasion resistance was good and the cleaning effect was sufficient. Also, the fitting force with the hub was sufficient, and no accidents such as the leader tape falling off occurred.

[Brief description of drawings]

1 and 2 schematically show the cross section of the leader tape for magnetic tape of the present invention. 1 ... Substrate film 2 ... Matt surface layer 3 ... Printing layer 4 ... Antistatic layer 5 ... Upper layer 10 ... Leader tape

Claims (1)

[Claims] 1. An abrasive-containing antistatic mat surface layer having any one of the following constitutions (a) to (c) is provided on at least one surface of a transparent substrate film, and the surface of the mat surface layer is provided. A leader tape for magnetic tape, comprising a pattern of a printed layer using a polyurethane resin as a binder. (A) A binder resin layer containing an antistatic-treated abrasive. (B) A binder resin layer containing an antistatic agent and an abrasive. (C) A binder resin layer containing an abrasive and an antistatic layer provided thereon.