JPS60231988A - Tape guide of cassette - Google Patents

Abstract

PURPOSE:To attain use of thermosetting resins for materials of a tape guide by forming the tape guide from a thermosetting resin binder including inorganic fillers. CONSTITUTION:Setting materials having a glass transition point of 100 deg.C or above are used for a thermosetting resin in order to ensure a heat resistance, and normally an epoxy resin is utilized. Inorganic fillers are added to the epoxy resin, so that a heat transfer coefficient of a tape guide can be 10X10<-4>cal/cm, deg,sec or above. The addition is 60-75wt% on the basis of total composites, because it would be difficult to satisfy requirements for said heat transfer coefficient in case of below 60wt%, while in case of beyond 75wt% the mechanical strength would be insufficient.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in tape guides for cassettes.

As shown in the figure, a cassette tape used in a magnetic recording/reproducing device has a cassette case/r, 1, two tape guides 2a, 2b, two tape guide posts 3a, 3b, a take-up rule 4a and The configuration includes a feed reel 4b,
The purpose of the tape guide is to keep the position of the magnetic tape constant and to ensure safe and smooth transfer of the magnetic tape to the magnetic recording/reproducing device.

Conventionally, this tape guide usually has a surface roughness of 0.5.
Hard chromium-plated stainless steel with a PM or less is used, but resin is being considered to reduce costs.
Tape guide pins made of polyacetal or polysulfone resins have been developed.

However, these resin tape guides have low thermal conductivity and are difficult to efficiently dissipate the heat generated by friction with the magnetic tape, resulting in significant heat generation.
There is concern that thermal stress may deform the tape guide or adversely affect the magnetic tape.

The tape guide for cassettes according to the present invention has a structure that allows the tape guide to be made of resin without the above-mentioned problems, and is a thermosetting resin molded material containing 60 to 75% by weight of an inorganic filler based on the total composition. It is characterized by being molded from.

In the present invention, the thermosetting resin used is a resin whose cured product has a glass transition point of 100°C or higher in order to ensure heat resistance against the heat generated by friction, and epoxy resin is usually used. Phenol resin, polyester resin, diallyl phthalate resin, etc. can also be used.

In the present invention, the reason why the inorganic filler is added is to increase the thermal conductivity of the tape guide to 10 x 10 can/d.
This is to make it greater than or equal to eg and sea. The reason why the amount added is set at 60 to 75% by weight based on the total composition is that if it is less than 60% by weight, it will be difficult to satisfy the above requirements for thermal conductivity, whereas if it is more than 75% by weight, the mechanical strength will be insufficient. Because it will be sufficient.

High hardness inorganic fillers, such as silica powder, alumina,
It is preferable to use nickel powder or the like. The particle size of the inorganic filler is preferably 0.1 to 40 μm in consideration of low friction properties (surface smoothness) of the tape guide.

In order to ensure low friction properties of the tape guide, a part of the inorganic filler is a low friction inorganic filler C with good sliding properties. Powder, silicon carbide powder, etc. can also be used, and in this case, the ratio (weight ratio) of high hardness inorganic filler/slidable inorganic filler is preferably 5/1 to 5/2.

Instead of using the above-mentioned sliding inorganic filler, it is also possible to use a resin powder with a low coefficient of friction (having a melting point higher than the heating curing temperature of the above-mentioned thermosetting resin), such as tetrafluoroethylene resin powder; in this case, The amount of resin powder added is 1 based on the total composition.
~5 weight range is appropriate; below 1 weight range, no effective reduction in the coefficient of friction can be expected, and above 5 weight range, the thermal conductivity is Cl0XIOcal/4. deg, see) is difficult to maintain.

In order to prevent the generation of static electricity due to friction between the tape guide and the electromagnetic tape, the surface insulation resistance of the tape guide should be set to 1.
The resistance may be set to 0 to 10 Ω, and therefore, nickel powder, molybdenum disulfide, carbon powder, etc. may be used as the inorganic filler.

Examples of the present invention will be described below.

Example 1 An epoxy resin composition (epoxy resin: Epicor 1001, curing agent: diaminodiphenylmethane), a mold release agent and silica powder C (high hardness inorganic filler) were mixed in the proportions shown in Table 1. Roll kneading is performed at 80°C, and the resulting molding material is passed through a tape guide (outer diameter: 6±0.05 ttt
m, inner diameter = 4.8 ± 0.05 mm, height: 16 ± 0.0
It was molded into a cylindrical body (No. 5) and heat-cured at 150 tC. .

Example 2 Example 2 was the same as Example 1 except that nickel powder was used instead of silica powder.

Examples 3 to 5 As shown in Table 1, high hardness inorganic fillers (silica powder, alumina powder) and low friction inorganic fillers (carbon fiber powder, molybdenum disulfide, silicon carbide powder) were used as inorganic fillers. Both were used, and the rest was the same as in Example 1.

Example 6 As shown in Table 1, silica powder was used as the inorganic filler, tetrafluoroethylene powder was added to reduce the coefficient of friction, and the other conditions were the same as in Example 1.

The thermal conductivity of each of these example products and the conventional product (polyacetal resin tape guide) was measured, and the results were as shown in Table 1.

Further, when the magnetic tape was run and the friction coefficient was measured under a pulling load of 100 g, the results were as shown in Table 1.

As mentioned above, in the tape guide for cassette according to the present invention, even if it is made of resin, it is blended with an inorganic filler and has a high thermal conductivity of < L (l0XIOca
II/3. deg, see) and the coefficient of friction can be made sufficiently low (0.3 or less), so that frictional heat generation can be effectively prevented, and the disadvantage (frictional heat generation) of conventional resin tape guides can be eliminated.

Furthermore, Table 1 also shows the measurement results of the surface insulation resistance.The use of a conductive filler as the inorganic filler is also advantageous in preventing the generation of static electricity.

[Brief explanation of the drawing]

In Figure 0, which is an explanatory diagram showing a cassette tape, 2 a + 2 b is a tape guide for the cassette.

Claims (3)

[Claims] (1) A tape guide for a cassette, characterized in that it is molded from a thermosetting resin molding material containing 60 to 75% by weight of an inorganic filler based on the total composition. (2) The tape guide for a cassette according to claim 1, wherein the entire amount of the inorganic filler is a high hardness inorganic filler. (3) The tape guide for a cassette according to claim 1, wherein the inorganic filler comprises a high-hardness inorganic filler and a low-friction inorganic filler.