JPH02192086A - Magnetic tape cassette case - Google Patents

Abstract

PURPOSE:To enhance dimension accuracy and dimension stability by including a coupling agent in a composite material composed of resin and inorganic filter. CONSTITUTION:In a magnetic tape cassette molded by the composite material including the resin and inorganic filler, the coupling agent is included in the composite material. As the using ratio of the resin, inorganic filler and coupling agent, the inorganic filler is 5-200 weight part and coupling agent is 0.1-10 weight part to the 100 weight part of the resin. When the coupling agent is less than this ratio, wettability between the resin and inorganic filler is made low and the dimension stability is lacked. When the coupling agent is too much, the adhesive power of the resin is lowered and a characteristic such as tensile strength is lowered. Thus, the dimension accuracy is enhanced and the dimension stability is made satisfactory even when the magnetic tape cassette case is used at a high temperature such as 40 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic tape cassette case with improved dimensional accuracy and dimensional stability.

[Conventional technology]

Magnetic tape cassettes can store audio tapes, video tapes, etc. and can be used as is for recording and playback, but the case generally consists of a lower case and an upper case molded from a single plastic material. Composed of combinations. As such plastic materials, polystyrene resin, acrylic resin, and polypropylene resin are used in the case of audio tape cassettes, and ABS resin is widely used in the case of video cassettes.

In recent years, metal magnetic powder has been used as a magnetic recording material, making it easier to record in the short wavelength range. The demands have become stricter.

In response to these demands, conventionally used cases made of single resin molded bodies such as polystyrene resin and ABS resin suffer from deformation and dimensional stability when the operating temperature range exceeds 40°C. was lacking.

In order to improve such dimensional stability, composite materials are used in which the resin is filled with an inorganic filler such as calcium carbonate.

[Problem to be solved by the invention]

However, because the affinity between resin and inorganic filler is poor, so-called low wettability, even if the inorganic filler is mechanically mixed and dispersed in the resin, it is difficult to disperse into the resin and cannot be uniformly dispersed. The fluidity is poor, the material of the molded body is uneven, and the dimensional accuracy and dimensional stability of the case are still insufficient.

An object of the present invention is to provide a magnetic tape cassette case with excellent dimensional accuracy and dimensional stability obtained from these composite materials by improving the wettability of the inorganic filler to the resin.

[Means to solve the problem]

In order to solve the above problems, the present invention provides a magnetic tape cassette molded from a composite material containing a resin and an inorganic filler, characterized in that the composite material contains a coupling agent. It is something to do. At this time, the composite material consists of 100 parts by weight of resin, 5 to 200 parts by weight of inorganic filler, and 0.1 to 1 of coupling agent.
It is also preferable to contain 0.060 parts by weight.

As the coupling agent used in the present invention, one or more of a silane coupling agent, a titanium coupling agent, and an aluminum coupling agent are used. Specifically, the following can be mentioned.

Silane coupling agent methyltrimethoxysilane, T-aminopropyltriethoxysilane, N-(β-aminoethyl)γ-aminopropyltrimethoxysilane, T-glycidoxypropyltrimethoxysilane, γmercaptopropyltrimethoxysilane, Examples include hexamethyldisilazane.

Titanium coupling agents include isopropyl trioctanoyl titanate, isobrobyl dimeccryl isostearoyl titanate, isopropyl tri(dioctyl phosphate) titanate, isopropyl tri(N-aminoethylaminoethyl) titanate, and the like.

Aluminum coupling agents include aluminum triisopropylate, ethyl acetoacetate aluminum diisopropylate, silminilamtris (acetylacetonate), cyclic aluminum oxide isopropylate, and the like.

Further, as the resin used in the present invention, IN or two or more kinds of resins such as polystyrene resin, acrylic resin, polypropylene resin, and ABS resin are used.

In addition, the inorganic fillers used in the present invention include CaCO3, TiO2, 5i02, ZnO, Fe2O
3, AI203, CrO2, Pt1504, Cu
O, etc., and one or more of these may be used. The average particle size of these inorganic fillers is 0.1 to 10.
0 μm is preferable. Incidentally, the particle size can be measured using a light transmission type particle size distribution meter.

The ratio of the resin, inorganic filler, and coupling agent used is 5 to 2 parts by weight of the inorganic filler per 100 parts by weight of the resin.
00 parts by weight, and 0.1 to 10 parts by weight of the cambling agent. If the amount of the coupling agent is less than this, the wettability between the resin and the inorganic filler will be low, resulting in a lack of dimensional stability. On the other hand, if the amount is too large, the adhesive force between resins will be reduced, and physical properties such as tensile strength will be reduced.

Other additives such as colorants and lubricants can also be used in the composite material used in the present invention. A so-called masterbatch, which is a coloring agent mixed with a resin in advance, can also be used.

To manufacture the magnetic tape cassette case of the present invention, the coupling agent may be blended with either or both of the resin and the inorganic filler, and then all the components may be blended, or these three components may be blended simultaneously. It's okay. At this time, it is preferable to blend the coupling agent in the form of a solution dissolved in an organic solvent such as toluene, since the coupling agent can be blended uniformly. The thus obtained blend of all components is melt-mixed and then molded, for example, by injection molding.

[Effect]

The parent wood group of the coupling agent is adsorbed to the surface of the inorganic filler,
Since the hydrophobic group faces the resin side, the resin and the inorganic filler are mixed with the coupling agent, and it is thought that the wettability of the inorganic filler to the resin is improved. It is thought that when the wettability is improved in this way, the fluidity during molding is improved and the material quality of the molded product becomes uniform.

〔Example〕

Example I GP-PS 70
Part (vitreous polystyrene, trade name Denka Styrol M)
T-2 (manufactured by Denki Kagaku Kogyo ■, used as a base material) Hr-PS 30
(High-impact polystyrene, trade name Denka Styrol, formerly S-1, used as impact resistance material) SBR1
0 parts (styrene-butadiene rubber, used as an earthquake-proofing material) Calcium carbonate 100 parts (average particle size 2.0, cam (particle size distribution 0.5-4.0)
cam)) Silane coupling agent
1 part (alkyl-based methyltrimethoxysilane) MB
5 parts (masterbatch consisting of carbon and resin (20:80)) The above mixture was melt-mixed using a mixer, and this mixture was molded using an injection molding machine to form a compact cassette half (Filsops model) shown in Fig. 1. A unilateral case) was obtained. We manufactured these and used a three-dimensional measuring machine (XYZA) for each.
X) (manufactured by Tokyo Seimitsu Co., Ltd.) to measure the horizontal and vertical dimensions shown in FIG. 1 (number of samples n = 100), and the results are shown in the table. In addition, 100.40±0.03 in the table is the average 100.4
0m, lower limit (100,40-0,03) tm, upper limit (
100,40+0.03) tm. The same applies to the vertical dimension.

Comparative Example 1 A cassette half was prepared in the same manner as in Example 1 except that the silane cuff pulling agent was not used, and the results of the same measurements are shown in Table 1.

Example 2 A cassette half was prepared in the same manner as in Example 1 except that 10.0 parts of the silane cuff pulling agent was used instead of 1 part, and the results of the same measurements are shown in Table 2.

Example 3 A cassette half was prepared in the same manner as in Example 1 except that an amino coupling agent was used instead of the alkyl coupling agent, and the results of the same measurements are shown in Table 2.

Example 4 A cassette half was prepared in the same manner as in Example 1 except that a titanium coupling agent was used instead of the silane coupling agent, and the results of the same measurements are shown in Table 2.

Example 5 A cassette half was prepared in the same manner as in Example 1 except that an aluminum coupling agent was used instead of the silane cuff pulling agent, and the results of the same measurements are shown in Table 2.

Table 2 From the above results, it can be seen that the variations in horizontal and vertical dimensions are small in all of the examples, but the variations in the comparative examples are several times larger.

〔Effect of the invention〕

According to the present invention, since a composite material of a resin containing a coupling agent and an inorganic filler is used as a molding material for a cassette case, flow is improved in the molding process, and a homogeneous molded cassette case can be obtained. This makes it possible to provide a cassette case with good dimensional accuracy and good dimensional stability even when used at high temperatures such as 40°C, and which can record in the short wavelength range like magnetic tape using metal magnetic powder. We can provide the optimal cassette case for each case.

[Brief explanation of the drawing]

1st The figure is a perspective view of the magnetic tape cassette case. January 20, 1999

Claims (2)

[Claims] (1) A magnetic tape cassette case molded from a composite material containing a resin and an inorganic filler, characterized in that the composite material contains a coupling agent. (2) Composite material includes 100 parts by weight of resin and 5 to 5 parts by weight of inorganic filler.
2. The magnetic tape cassette case according to claim 1, wherein the magnetic tape cassette case contains 200 parts by weight and 0.1 to 10.0 parts by weight of a coupling agent.