JPH063676B2 - Sliding sheet for cassette tape - Google Patents

Description

TECHNICAL FIELD The present invention relates to a cassette tape slip sheet used between a magnetic tape and a cassette case in an audio cassette tape or a video cassette tape.

<Prior Art> For audio cassette tapes and video cassette tapes, the magnetic tape and the cassette case are used to reduce the friction between the inner wall surface of the cassette case and the end surface of the tape when the magnetic tape is running and to prevent the charging. A slippery sheet is arranged between the inner wall surfaces.

Conventionally, as a slippery sheet, a polytetrafluoroethylene sheet or the like having a small friction coefficient and excellent thermal stability has been used. However, this sheet is expensive, and static electricity is locally generated due to friction with the reel and the tape, which deteriorates the running property of the reel and the tape, is too flexible and has a weak waist, and the periphery of the sheet is bent. There is a drawback in that the work of mounting the cartridge in the cartridge is troublesome because it deviates from a predetermined position. Also known is a sheet based on paper, which has been treated with silicone to provide lubricity, but this sheet has poor water resistance, and changes in dimensions due to moisture absorption, causing curling and tarmi, and causing slippage. It has a drawback that the property is deteriorated.

<Problems to be Solved by the Invention> The present invention solves the above-mentioned drawbacks and provides a slip sheet for a cassette tape, which can provide excellent running stability and durability of a magnetic tape.

<Means for Solving the Problems> The present invention relates to a polyester-based, polyurethane-based, or acrylic-based support having at least one group of a hydroxyl group, a carboxyl group, an amino group, and an epoxy group in the molecule on at least one surface of a support. A slip sheet for a cassette tape, which is provided with a surface layer composed of a resin and a silyl isocyanate compound.

The silyl isocyanate compound used in the present invention,
Si (NCO) ₄ having a Si-NCO bond in the molecule and the following general formula
It refers to a series of compounds represented by (1) and (2), and further includes polycondensation products of these compounds.

General _{formula: R n Si (NCO) 4} -n ... (1) (RO) n Si (NCO) 4-n ... (2) ( wherein, n represents 3 an integer, R represents an alkyl group, an aryl group, It represents an alkenyl group.) Among these silyl isocyanate compounds, those containing an alkyl group in the molecule are particularly preferable.

The polyester-based, polyurethane-based, or acrylic-based resin having at least one group selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group, and an epoxy group used in the present invention means those functional groups of a polymer molecule. It is a homopolymer or copolymer resin having a main chain, a side chain, or a molecular end. That is, a glass transition point of 60 ° C. containing acrylamide, N-methylol acrylamide, diacetone acrylamide, dimethylaminoethyl (meth) acrylate, glycidyl (meth) acrylate, (meth) acrylic acid, itaconic acid, maleic acid and the like as a copolymerization component. The above acrylic resin, polyester resin,
A polyurethane resin is used in the present invention in terms of adhesion to a support and heat resistance.

The surface layer in the present invention is composed of the resin and the silyl isocyanate compound as described above, and good surface slipperiness can be obtained by the silyl isocyanate compound.
The specific resin as described above is used in order to fix the silyl isocyanate compound and to have the function of binding the surface layer to the support and to obtain good durability. That is, a hydroxyl group, a carboxyl group, an amino group, an epoxy group and the like existing in the resin molecule react with the isocyanate group of the silylisocyanate compound to fix the silylisocyanate compound on the surface layer. The mixing ratio of the silylisocyanate compound and the resin in the surface layer is 9: 1 to 1: 9 by weight, and particularly 8:
2 to 4: 6 is preferable. The surface layer in the present invention is
In addition to the above-mentioned resin composed of the specific resin and silyl isocyanate compound, those containing other components as required are also included. For example, for the purpose of improving blocking resistance, fine particles of silica, clay, talc, calcium carbonate, calcium sulfate, barium sulfate, aluminum silicate, synthetic zeolite, alumina, zinc oxide, lithopone, satin white, various resin fine powders, etc. It is also possible to add.

The surface layer as described above is a coating material prepared by uniformly dispersing or dissolving the material for forming the surface layer in a suitable solvent,
A method such as roll coating, blade coating, spray coating, air knife coating, rod coating, or the like, in which coating and drying is performed on a support, or a mixture of the above materials for forming the surface layer is uniformly mixed. It can be formed by a method of providing it on a support by a hot melt coating method, a laminate coating method, or the like. Surface layer thickness is 0.1 ~
About 2 μm is suitable.

Examples of the support used in the present invention include thermoplastic resin films such as polyethylene terephthalate, polyvinyl chloride, diacetate, triacetate, acrylic polymers, cellophane, celluloid, and polycarbonate. Among them, polyethylene terephthalate film has strength and cost. It is effective and preferable in terms of. The thickness of the film is generally 5 to 100 μm, preferably 10 to 50.
It is about μm. As the film, a transparent film, a milky white film, a colored film, or the like can be appropriately selected depending on the application.

As described above, the cassette tape slip sheet of the present invention has a surface layer provided on at least one side of a support. However, it is possible to use the slide sheet for front and back without distinction. The surface layer may be provided on both sides of the support. Also. Since the surface layer is made of resin, antistatic treatment is preferably performed because the surface resistivity is high and frictional charging is likely to occur depending on the type and composition of the material used. As a method of antistatic treatment, an antistatic film containing an antistatic agent as a support is used. The antistatic agent may be contained in the surface layer, and an antistatic layer may be provided between the support and the surface layer and / or on the surface of the support opposite to the surface layer. You can Examples of the antistatic agent used here include surfactant-based agents such as cation-based and anion-based agents, acrylic polymer-based agents, and polysiloxane-based agents. To provide an antistatic layer, the above antistatic agent may be added by adding a binder if necessary to prepare a coating composition, which is then applied and dried on a support. In order to obtain a sufficient antistatic effect, it is preferable that the surface specific resistance under the environment of 20 ° C. and 65% RH is 1.0 × 10 ¹² Ω / □ or less.

<Examples> Next, the present invention will be described in detail with reference to Examples. In addition, all the parts showing the composition represent parts by weight.

Example 1 A polyethylene terephthalate film (Teijin Tetron film S type, thickness: 50 μm, manufactured by Teijin Ltd.) was used as a support, and a coating composition having the following composition was applied to one surface and dried to provide an antistatic layer having a thickness of 1 μm. .

Next, a coating material having the following composition was applied onto the antistatic layer and dried to form a surface layer having a thickness of 0.5 μm, to prepare a slip sheet of the present invention.

Example 2 Except that the coating composition for the surface layer having the following composition was used,
The slippery sheet of the present invention was produced in exactly the same manner as in Example 1.

Example 3 except that the following composition was used as the surface layer coating material:
The slippery sheet of the present invention was produced in exactly the same manner as in Example 1.

Example 4 Except that the coating composition for the surface layer having the following composition was used,
The slippery sheet of the present invention was produced in exactly the same manner as in Example 1.

Example 5 After providing an antistatic layer on both sides of the support in Example 1, a coating material having the following composition is applied on the antistatic layer on one side of the support and dried to form a surface layer having a thickness of 0.5 μm. To produce the slip sheet of the present invention.

Example 6 Except that the following composition was used as the surface layer coating material,
A slip sheet of the present invention was produced in exactly the same manner as in Example 5.

Example 7 In Example 1, after providing an antistatic layer on one surface of the support, a coating material having the following composition was applied to the other surface of the support.
After drying, a surface layer having a thickness of 0.5 μm was provided to prepare a slip sheet of the present invention.

Comparative Example 1 Except that the surface layer coating material having the following composition was used,
A slip sheet for comparison was prepared in exactly the same manner as in Example 1.

Comparative Example 2 Except that the surface layer coating material having the following composition was used,
A slip sheet for comparison was prepared in exactly the same manner as in Example 1.

Comparative Example 3 Except that the surface layer coating material having the following composition was used,
A slip sheet for comparison was prepared in exactly the same manner as in Example 5.

Comparative Example 4 Except that the surface layer coating material having the following composition was used,
The slippery sheet of the present invention was produced in exactly the same manner as in Example 1.

The above-described slip sheets of Examples 1 to 7 and Comparative Examples 1 to 4 were processed into a predetermined form and incorporated into a commercially available audio cassette tape (90-minute recording type). This cassette tape was fast forwarded and rewound 200 times with a cassette recorder to examine the running property and durability of the tape.

As a result, as shown in Table-1, it was confirmed that the slippery sheet of the present invention had excellent properties. The evaluation method is as follows.

1) Runnability: The level of generation of frictional noise / running sound during fast-forwarding / rewinding of the tape was low, and the tape was running well.

2) Durability: After repeating fast-forwarding and rewinding the tape 200 times, good results were obtained without stretching at the end of the tape, and wavy ones with stretching at the end of the tape. It was set to x.

3) Dynamic friction coefficient; TAPPI Paper Pulp Test Method No.3
According to the method of 0-79, the surface layer surface of the slip sheet and the untreated PET film surface were combined and measured with a load of 75 g.

<Effects of the Invention> Since the cassette tape slippery sheet of the present invention has good surface slipperiness, it is possible to obtain good running stability and durability of the magnetic tape with less generation of noise due to friction and chargeability. It is what is done.

Claims (1)

[Claims] 1. At least one of a hydroxyl group, a carboxyl group, an amino group and an epoxy group on at least one surface of a support.
A slip sheet for a cassette tape, comprising a surface layer composed of a polyester, polyurethane or acrylic resin having one group in the molecule and a silyl isocyanate compound.