JPS6243882A - Transparent sheet material for reel type cassette tape - Google Patents

Abstract

PURPOSE:To hold excellent antistatic performance for a long period by providing a slip layer made of a transparent radiant ray curing resin layer including an antistatic agent to at least one face of a transparent base sheet material. CONSTITUTION:The slip layer 2a incorporated with an antistatic agent is formed to at lest one face of the base sheet material 1. The slit layer is made of a radiant ray curing composition including a pre-polymer having at least one ethylenically unsaturated bond in molecules, or olygomer and a monomer as essential components. As to the base sheet material, for instance, a material such as a polyethylenetelephthalate, a polyvinylchloride, a polycarbonate or a polystylene is used, and as the antistatic agent, various surface active agent type antistatic agent such as cationic antistatic agent, anionic antistatic agent or nonionic antistatic agent is used.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a transparent sheet material for reel-type cassette tapes, and relates to a reel-type cassette tape with excellent transparency, permanent antistatic properties, and excellent slip properties. □The purpose is to provide transparent sheet materials for tapes.

(Prior Art) Conventionally, a slip sheet has been provided between the cassette half of a cassette tape and the tape in order to prevent the tape and reel of a cassette tape from being electrostatically charged and to ensure smooth rotation of the tape and reel. . However, since the slip sheet is fixed in half, and the tape rotates while contacting the slip sheet, the tape tends to wind irregularly, causing problems in running performance. Therefore, a reel-type cassette tape was devised in which the reel was sandwiched between transparent notebooks and the entire reel could rotate freely. FIG. 5 shows an example of a reel type cassette tape, and 4 in the figure is a reel type □cassette tape. The ends of the cassette tape 4 are fixed to a pair of hubs 10.10, and the other ends of a wound cleaning leader tape 11.11 are connected by a magnetic tape 12 to a pair of glue bars 5,5.
A total of four metal flanges 7 sandwiched between two transparent sheets 6 on both sides of each reel 5, 5 are attached to each hub 10.
．． The hub 10.10 is further fitted into a pair of transparent cassette halves 8, 8, and each cassette half 8.8 is fixed with screws 9.

In this way, the reel type cassette tape 4 has reel 5,
Since the rotation of tape 5 contacts only the edges of heps 10 and 10 in the center, the rotational torque is lower than that of conventional cassette tapes, and stable running performance can be obtained. The material used to form the transparent sheet used in this reel type cassette tape must be transparent so that the rotating state of the reel can be observed from the outside of the cassette no. It is preferable to use a material that can prevent the adhesion of stiffness, remove static electricity generated during tape running, and maintain its f[ability even after long-term single use.

Conventionally, sheet materials of this type and those in which an antistatic agent or lubricant was applied to the surface of a transparent resin sheet were used. Proposed.

(Problems to be Solved by the Invention) However, in such conventional sheet materials, the antistatic agent and lubricant tend to fall off, resulting in a decrease in antistatic properties and lubricating properties. There are problems in that the inhibitor and lubricant adhere to the tape and the cassette half, making it difficult to run the tape smoothly and spoiling its appearance.

(Means for Solving the Problems) The present invention has been made by focusing on such conventional problems, and is a reel type that has excellent transparency and antistatic properties and can maintain excellent performance over a long period of time. The purpose of the present invention is to provide a transparent sheet material for cassette tapes.

That is, the present invention is characterized in that it consists of a transparent pace sheet material and a slip layer provided on at least one surface of the base sheet material, and that the slip layer is a transparent radiation-cured resin layer containing an antistatic agent. This is a transparent sheet material for reel type cassette tapes.

Next, to explain the present invention in more detail, the main feature of the present invention is that a transparent radiation-cured resin layer is used as a resin layer containing an antistatic agent and a lubricant when forming a transparent sheet material, Because of these characteristics, it was possible to provide a transparent sheet material for reel type cassette tapes that has excellent transparency and abrasion resistance and can maintain sufficient antistatic properties and slip properties even after being used for a period of K.

As the base sheet material used to construct the transparent sheet material of the present invention as described above, any conventionally known base sheet material can be used as is as long as it is transparent, such as polyethylene terephthalate, polybutylene terephthalate, ethylene, etc. Examples include -vinyl acetate copolymer, saponified product of ethylene-vinyl acetate copolymer, polyvinyl alcohol, nylon, polypropylene, polyethylene, polyvinyl chloride, polycarbonate, polystyrene, cellophane, and double acid-resistant cellulose. These base sheet materials preferably have a thickness of 30 to 150 μm.

As the antistatic agent used in the present invention, any conventionally known antistatic agent can be used, such as quaternary ammonium salts, pyridinium salts, and various types having cationic groups such as primary to tertiary amino groups. Cationic antistatic agents, anionic antistatic agents with anionic groups such as sulfonate bases, sulfate ester bases, phosphate ester bases, phosphonates, amphoteric antistatic agents such as amino acid bases, amino sulfuric acid: n-ster bases, etc. , various surfactant type antistatic agents such as nonionic antistatic agents such as amino alcohol type, glycerin type, polyethylene glycol type, etc., and polymer type antistatic agents made by increasing the molecular weight of the above antistatic agents. In addition, monomers and oligomers that have a tertiary amino group or a quaternary ammonium group and can be polymerized by radiation,
For example, polymerizable antistatic agents such as N,N-dialkylaminoalkyl (meth)acrylate monomers and quaternized products thereof (r) can also be used.

In particular, when such polymerizable antistatic IL agents are used, these antistatic agents are integrated with the resin layer to be formed, so that long-term stable antistatic properties can be achieved.

There is no particular restriction on the amount of the antistatic agent as described below, but it is generally preferred that the half-life of static electricity of the obtained transparent sheet material be 60 seconds or less.

As the lubricant used as necessary in the present invention, any conventionally known lubricant can be used, but examples include silicone resin, fluorine resin, and specifically silicone oil for paint addition: KP-3'01 (Shin-Etsu Chemical System), anti-blocking fluororesin Nylbrone IjI)-100 (manufactured by Daikin Industries), and the like are useful.

Such a lubricant should be present in the slip layer to form a slip layer of about 0.01 to 2.0
It is preferable to use it in a proportion accounting for 0% by weight; if the amount used is less than 0.1% by weight, sufficient surface smoothness will not be achieved, and even if it exceeds 20% by weight, no further surface smoothness effect will be achieved. Not only is it uneconomical because no improvement in the lubricant is observed, but the lubricant bleeds to the surface of the tape, which reduces the transparency and antistatic properties of the slip sheet, and also causes the lubricant to migrate to the magnetic tape. This is not preferable because it causes problems such as contaminating the magnetic tape and magnetic head.

The radiation-cured slip layer used in the present invention and which mainly characterizes the present invention is a compound that can be polymerized and cured by conventionally known radiation, such as electron beams or ultraviolet rays, to form a strong film. It is formed from a curable composition whose main components are a prepolymer or oligomer having at least one ethylenically unsaturated bond therein, and a hexamer.

Such prepolymers or oligomers include
For example, unsaturated polyesters, polyester acrylate, Evoquin acrylate, urethane acrylate,
Polyether acrylate, polyol acrylate 1
．． Various acrylates such as melamine acrylate, polyester methacrylate, Evoquin methacrylate,
Examples include one or more types of methacrylates such as urethane methacrylate, polyether methacrylate, polyol methacrylate, and melamine methacrylate.

In addition, examples of heptamers having an ethylenically unsaturated bond in the molecule include styrene monomers such as styrene and α-methylstyrene; methyl acrylate, acrylic acid-
Acrylic acid esters such as 2-ethylhexynyl, methquinethyl acrylate, butquinethyl acrylate, butyl acrylate, methquinbutyl acrylate, phenyl acrylate; methyl methacrylate, ethyl methacrylate,
Propyl methacrylate, methacrylate ethyl methacrylate,
Ethquinmethyl methacrylate, phenyl methacrylate,
Methacrylic acid esters such as lauryl methacrylate; Unsaturated carboxylic acid amides such as acrylamide and methacrylamide: (N,N-dimethylamino)ethyl methacrylate, (N,N-dibenzylamino)ethyl methacrylate, methacrylic acid ( N.

Substituted amino alcohol esters of unsaturated acids such as N-dimethylamino)methyl and (N,N dimethylamino)propyl methacrylate; ethylene glycol diacrylate, propylene glycol diacrylate, neopentyl glycol diacrylate, 1,6-hexane Polyfunctional compounds such as thiol real acrylate, diethylene glycol real acrylate, triethylene glycol diacrylate, dipropylene glycol diacrylate, ethylene glycol dimethacrylate, propylene glycol dimethacrylate, diethylene glycol dimethacrylate, and/or two or more compounds in the molecule. Examples include mixtures of polythiol compounds having a thiol group, such as trimethylolpropane trithioglycolate, trimethylolpropane trithiopropionate, pentaerythritol tetrathioglycolate, and the like.

There is no particular restriction on the composition ratio of the mixture in the resin composition, and they can be mixed arbitrarily and used,
In order to provide a suitable coating for ordinary coatings, it is preferable that the amount of the prepolymer or oligomer be 5% by weight or more and the amount of the monomer and/or polythiol be 95% by weight or less.

The following components are the main components of the radiation-curable composition used in the present invention, and organic solvents for viscosity adjustment and materials that can be used in the slip layer to be formed are included, as long as they do not interfere with the transparency of the slip layer to be formed. It is possible to optionally include various compatible non-reactive polymers to adjust flexibility and hardness, various fillers that do not impair transparency, or polymerization inhibitors to improve storage stability. Of course.

Such a radiation-curable coating composition can be cured by any radiation, but for example, when electron beams or gamma rays are used as the radiation, the radiation dose is preferably in the range of 1 to 20 Mrad. be.

In addition, when ultraviolet rays are used as the radiation, sensitizers such as benzophenones such as benzophenone and Michler's ketone, benzoins such as benzoin and benzoin alkyl ether, and monogenated acetophenone are added to the coating composition. It is preferable to appropriately incorporate a compound that generates free radicals when exposed to ultraviolet rays, such as Piacetyl and Piacetyl.

The transparent sheet material for reel type cassette tapes of the present invention is formed from the above-mentioned materials. Preferred embodiments of the transparent sheet material of the present invention will be specifically described with reference to the accompanying drawings. 2 and 2 schematically show a cross-section of a transparent slipsheet material of a preferred embodiment of the present invention, and FIG. 3 schematically shows a cross-section of a transparent slipsheet material of another preferred embodiment. [1] Figure 4 schematically shows a cross-section of yet another preferred embodiment of transparent slip sheet material.

The embodiment shown in FIG. 1 has a slip layer 2 containing an antistatic agent on at least one side of the base sheet material 1.
It is formed by a.

The embodiment shown in FIG. 2 is one in which a slip layer 2b containing both an antistatic agent and a lubricant is formed on at least one surface of the base sheet material 1, and the embodiment shown in FIG. In this case, the slip layer formed on at least one side of the paste material 1 has a two-layer structure, the first layer 2a of which is a radiation-cured resin layer containing an antistatic agent, and the second layer 2C on top of which is a radiation-cured resin layer containing a lubricant. This layer 2C may be formed as a radiation-cured resin layer containing a lubricant.

Another embodiment shown in FIG. 4 is one in which the transparent notebook material of the above embodiment is further embossed.

The method of forming the transparent sheet material for the reel type cassette tape of the embodiment shown in FIGS. 1 and 2 may be a known method. For example, in the case of FIG. The above-mentioned radiation-curable coating composition is mixed with the above-mentioned radiation-curable coating composition to form a slip layer-forming paint, and this paint is coated by a coated jig method such as a roll coating method, a gravure coach ink method, a screen coating method, a fountain coating method, etc. After coating at least one side of said base sheet material and then optionally drying the solvent,
It is obtained by curing by the above-mentioned curing method to form a slip layer.

The thickness of the slip layer formed in this way is such that the solid content coating amount is 0.1 to 49/rr? It is preferable that the thickness be such that the thickness is approximately the same.

In addition, in order to form the transparent sheet material of the embodiment illustrated in FIG. A coating composition containing the antistatic agent is prepared separately, first coating and curing the coating composition containing the antistatic agent on at least one side of the base sheet material as described above, and then coating the surface of this antistatic agent layer on the surface of the antistatic agent layer. This can also be obtained by forming a slip layer.

In such an embodiment, the antistatic agent layer a preferably has a thickness of about 0.1 to 47 mm solids, and the lubricant layer has a solids coating of about 0.1 to 4 mm. ~2 Si'
/ m' thickness is preferred.

Although in the above embodiments the slip layer is provided on one side of the base sheet material, the present invention is not limited to these embodiments; for example, although not shown, the slip layer is provided on one side of the base sheet material. It may be provided on both sides, or
Any structure may be used, such as providing a two-layer slip layer on one surface and providing an intercharge agent layer on the other surface.

The embodiment shown in FIG. 4 is an embodiment in which the transparent sheet material for reel type cassette tape of the present invention as shown in FIGS. 1 to 3 is embossed, and such embossing is conventionally known. It can be applied to the container using an embossing roll or the like.

In this embodiment, both sides of the sheet material are embossed, but when forming the slip layer, glass beads or resin beads of an appropriate size that do not impair transparency are added to the coating solution. By forming the slip layer, it is also possible to perform embossing only on the slip layer. By applying such embossing, the contact area between the slip sheet and the magnetic tape or reel is reduced, further reducing friction when the magnetic tape runs,
Static electricity generation due to friction can be reduced.

(Operation/Effect) According to the present invention as described above, the base sheet material constituting the transparent sheet material for reel type cassette tape of the present invention is transparent, and the slip layer formed on at least one surface thereof is also transparent. Therefore, the entire sheet is transparent.

Therefore, it is useful as a sheet for reel-type cassette tapes whose cassette leaves are transparent.

In addition, the slip layer of the transparent sheet material for reel type cassette tapes of the present invention is formed of a radiation-cured resin layer containing an antistatic agent and/or a lubricant, and this radiation-cured resin layer is a general air-drying resin layer. Also, unlike a resin layer made of thermosetting paint, it is a very tough and wear-resistant resin layer, so the antistatic agent and/or lubricant contained therein will prevent the tape or reel from bonding. Since it does not fall off from the resin layer upon contact, the sheet can maintain excellent antistatic properties and surface smoothness for a long period of time.

In particular, when using a difunctional or higher functional monomer, oligomer, or prepolymer as the radiation-curable resin in the present invention, the radiation-curable resin layer formed is formed from a cured resin with a network structure with a high crosslink density. , the above effects are further improved.

In addition, by employing a polymerizable antistatic agent having a tertiary amine or quaternary ammonium group that can be copolymerized with radiation-curable monomers, oligomers, or prepolymers, these antistatic agents can be used as antistatic agents. Since the antistatic agent is integrated with the radiation-curable resin that forms the slip layer, the antistatic agent does not bleed out or fall off during use, and exhibits even better antistatic properties that are stable over a long period of time. It is something.

Next, the present invention will be explained in more detail with reference to Examples. In the text, parts or parts are based on weight unless otherwise specified.

Example 1 5T-3600 (antistatic agent: manufactured by Mitsubishi 411 Kafine Co., Ltd.) 5 () parts Trimethylolpropane triacrylate 50 parts KP-
301 (Silicone oil: Shin-Etsu Chemical Co., Ltd.) 1 part isopropyl alcohol 50 parts methanol
50 parts The coating liquid having the above composition was applied to a gravure plate having a plate depth of 40 μm, and a plate having a thickness of 5 mm was treated with corona discharge.
0μm polyester film with solids coating amount of 0
．． 39/ni", dry the solvent,
An electron beam accelerated to 175 kV in a nitrogen gas atmosphere is
Mrad irradiation and curing to form a slip layer;
A transparent sheet material for a reel type cassette tape of the present invention was obtained.

The electrostatic half-life of the resulting transparent base sheet material was 30 seconds or less.

Here, the electrostatic half-life is calculated as follows: 1.
The sample was rotated at 0.000 rpm, a voltage of 5 kV was applied, and a charge was applied to the sample for 30 seconds by corona discharge, and then the charged voltage of the sample was measured in an atmosphere of 25° C. and 50% RJI.

The measuring machine is a Mod from Kawaguchi Electric Works.
An el SP-423 electrostatic paper analyzer was used.

Next, the above notebook material is cut into a predetermined size and shape and interposed between the magnetic tape and the cassette half.
When used as a transparent notebook material and subjected to a durability test of 400 replays and rewinds, it exhibited excellent antistatic properties and did not cause problems such as dust adhesion to the magnetic tape or irregular winding of the tape.

Example 2 The same transparent notebook material as in Example 1 was embossed on both sides using a heated embossing roll, and then cut into a predetermined size and shape.

A durability test was conducted under the same conditions as in Example 1 using a transparent sheet for reel type cassette tape.
The tape had good transparency and excellent surface smoothness, and no dust was attached to the tape or the tape was wound irregularly.

Example 3 The following composition was placed in a reaction container that could be heated and stirred,
The mixture was refluxed for 10 hours to obtain a polymer.

Methyl methacrylate) 200 parts dimethylaminoethyl acrylate) 91012-Hydroquine ethyl methacrylate) 26 ('1 part α,
α'-azobisinbutyronitrile 5 parts Ethyl acetate 4,100 parts Next, 1 part by weight of benzoquinone was added to stop the reaction, and 640 parts of
Parts of 2-human [1 quinethyl methacrylate and 2.4-
)/leen diisonanate (1 mole to 1 mole adduct) was added, and 50 parts of dibutyltin silaurylate was added, and the mixture was reacted at 80° C. for 5 hours while blowing dry air.

Next, 1,000 parts of methyl ethyl ketone, 450 parts of allyl chloride, and methyl alcohol! 1.200 parts were added and reacted at 80'C for 4 hours.

After the reaction solution was cooled to room temperature, 200 parts of an ultraviolet sensitizer (Irgacure 184, manufactured by Ciba Geigy) was added to obtain an ultraviolet curable coated T material.

This was applied to a corona discharge treated polyester film (thickness: 38 μm) using a gravure coating method, with a solid content of 19
/ m”, dry the solvent and run under 10(1) of an ultraviolet lamp with an output of 80 kW / cyn under a nitrogen gas atmosphere at a speed of 10 m / mi.
A transparent resin layer was formed by curing the resin layer.

Next, on top of this resin layer, an anti-blocking agent, Lublon LD-100 (manufactured by Daikin Industries) was diluted with toluene as a lubricant, and the dry coating amount was reduced to 0 by roll coating.
．． The transparent sheet material for reel-type cassette tapes of the present invention was obtained by coating the film at a coating thickness of 59/m'' and removing the solvent to form a lubricant layer.

The electrostatic half-life of this transparent basenote material was less than 60 seconds.

In addition, after processing both sides of the above slip notebook material using a heated embossing roll, it was cut into a predetermined size and shape, and used as a transparent notebook material for reel type cassette tape, and was subjected to the same durability test as in Example 1. When tested, it was found that the tape had good transparency, excellent surface smoothness, and no dust adhesion to the tape or irregular winding of the tape.

[Brief explanation of drawings]

1 and 2 schematically illustrate a cross-section of a transparent slipnote material of a preferred embodiment of the present invention, and FIG. 3 illustrates a cross-section of a transparent slipnote material of another preferred embodiment. and FIG. 4 shows yet another preferred embodiment of a transparent slip notebook material 2; a slip layer 2a; an antistatic agent layer 2b; a layer 2C containing an antistatic agent and a lubricant;
Lubricant layer 3; Embossed transparent notebook material 4;
Reel type cassette tape 5; reel 6; transparent notebook 7; metal flange 8; cassette half 9; screw In; /, pull 11; cleaning leader tape 12; magnetic tape

Claims (4)

[Claims] (1) Consisting of a transparent base sheet material and a slip layer provided on at least one surface of the base sheet material,
A transparent sheet material for a reel type cassette tape, wherein the slip layer is a transparent radiation-cured resin layer containing an antistatic agent. (2) The transparent sheet material for a reel type cassette tape according to claim (1), wherein the slip layer contains an antistatic agent and a lubricant. (3) The reel type cassette according to claim (1), wherein the slip layer has a two-layer structure, the first layer in contact with the base sheet material contains an antistatic agent, and the second layer comprises a lubricant. Transparent sheet material for tape. (4) The transparent sheet material for a reel type cassette tape according to claim (1), wherein at least one surface is embossed.