JPS6144440B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to casings for audio equipment, such as speaker cabinets, record player housings, and cassette recorder cases with portable radios. Conventionally, plastics have been mainly used for the housings of small and simple speaker systems, record players, portable radios, etc., but housings made of plastics or fiber-reinforced plastics are easy to mold. However, because it is lightweight, it is prone to resonance and is susceptible to external vibrations. This is because no one with a sufficiently large internal loss was found. Furthermore, in speaker cabinets for high-speed phones and record player housings, attempts were made to suppress unnecessary resonance by increasing internal loss by using wood-based materials. However, in the case of wood-based materials, there was a problem in that assembly processing was time-consuming. Metal casings are also used in car stereos and small high-fidelity stereos. The problem with this metal housing is that, like plastic, it has low internal loss. In view of this problem, the present inventors have proposed speaker cabinets and player housings made of a material obtained by mixing and kneading graphite powder into plastic. This material, which is a mixture of plastics and graphite powder, is lightweight, has high elasticity, and has a high internal loss. however,
This material has problems with temperature resistance, and although it is suitable for indoor audio equipment, there is a risk of deformation when it is exposed to high temperatures due to direct sunlight in midsummer, such as in car stereos. Ta. The present invention was made in view of such conventional problems, and an object of the present invention is to provide a housing for audio equipment that is lightweight, has high elasticity, high internal loss characteristics, and also has excellent temperature resistance characteristics. do. The present invention will be explained in detail below. The present invention is characterized by post-chlorinated vinyl chloride alone or a mixture of post-chlorinated vinyl chloride and polymethyl methacrylate, and if necessary, nitrile butadiene rubber (NBR), butyl rubber (IIR) in addition to these synthetic resins.
The casing for audio equipment is made of a mixture of a mixed material containing a rubber material such as styrene butadiene rubber (SBR) and flaky graphite powder. Furthermore, the present invention is characterized by a housing for an audio device, which is formed from the above-mentioned kneaded material and further includes flaky graphite powder oriented along the surface. When discussing heat resistance at the temperature at which the elastic modulus is halved, post-chlorinated vinyl chloride has a heat resistance that is 10 to 20°C higher than that of vinyl chloride resin, and polymethyl methacrylate (PMMA) has a heat resistance that is 10°C higher than that of vinyl chloride resin. It's nearby and expensive. Therefore, these synthetic resins have better heat resistance than molding materials based on vinyl chloride resins. Rubber-based materials contribute to improving internal loss due to their softness. The flaky graphite powder contributes to an improvement in the elastic modulus that cannot be expected from a resin alone, and especially when its orientation is aligned in one direction, the elastic modulus is significantly improved. The flaky graphite powder preferably has an average particle size of about 20 μm or less, particularly 5 μm or less. Further, if the blending ratio of graphite powder and resin is in the range of 10 to 90 Wt% of graphite powder and 90 to 10 Wt% of resin, it is expected that the graphite powder will improve the elastic modulus without impairing the moldability. It hardly causes embrittlement of the molded product, but especially graphite powder 50~75Wt%, resin 50~
At 25 Wt%, the properties are significantly improved.
PMMA is widely used as a processing aid for post-chlorinated vinyl chloride, but the blending ratio of the two can be arbitrarily determined and can be changed depending on the shape and properties of the intended molded product. The rubber material is added as needed in the range of 2 to 50 Wt% to the resin, and if it is added about 10 Wt%, the facultability E is about 20
% decrease, but the internal loss tan δ is improved by about 1.5 to 2 times. When manufacturing audio equipment casings, we first use post-chlorinated vinyl chloride alone or a mixed resin material of post-chlorinated vinyl chloride and polymethyl methacrylate, and if necessary, a resin material with rubber-based materials added thereto. 1 and flaky graphite powder 2 are mixed, and if necessary, a plasticizer or stabilizer is added and mixed, and the mixture is heated to 130°C, which is the softening and melting temperature of the resin material, using a kneader or roll as shown in Figure 1. Knead while heating at ~180°C. This kneaded material 3 is used as it is for molding casings such as speaker cabinets, player housings, radio cassette cases, etc. by appropriate molding methods such as compression molding, injection molding, and press molding. For example, taking compression molding as an example, as shown in Figure 2, material 3 is put into a mold 4 corresponding to the shape of the intended housing, and then mold 5 is fitted with mold 4 and heated. The material 3 is made to flow to every corner within the molds 4 and 5 by applying pressure, and then the molds 4 and 5 are cooled. Next, the mold 4.5 is opened and the molded product 6 is taken out from inside. Figures 3a, b, and c show speaker cabinets 7 and 7 molded by the above method, respectively.
Player housing 8, radio cassette case 9
shows. In the above-mentioned kneaded material 3, since the graphite powder 2 is not oriented in one direction within the resin material 1, the elastic modulus E is 1/2 to 1/3 of that when it is oriented, but the high internal loss is unchanged. First, it is used for molding casings for audio equipment, which only need to have sufficient damping characteristics against vibrations. The kneaded material 3 is rolled many times with rolls to improve its elastic modulus and is formed into a sheet as shown in FIG. 4. By forming the graphite powder into a sheet by roll rolling, the graphite powder 2 is oriented along the band surface of the sheet material 10, and its elastic modulus is increased to 2 to 3 times that of the unoriented one. This sheet material 10 is stacked one sheet or an appropriate number of sheets as shown in FIG. 5 as needed, and is formed into a desired audio equipment casing by a molding method such as vacuum forming, pressure forming, press forming, etc. under heating. . If the housing is a speaker cabinet, the front plate 11a, upper plate 11b, and
A suitable method is to mold the side plate 11c and the bottom plate 11d separately and assemble them, or to simultaneously mold them into the shape shown in Figure 3a by hot press molding plates of the required thickness. There is. Also, where the case is the player housing, there is a third
Either one plate material is press-formed into the shape shown in Figure b and simultaneously formed into one piece, or a plate material 12 obtained by laminating sheet materials 10 to the required height as shown in Figure 7 is used. This can be obtained by drilling necessary holes 12a and 12b for incorporating the device into this. Furthermore, if the housing is a radio cassette case, it is suitable to obtain it by press molding into the shape shown in FIG. 3c. The present invention will now be explained based on examples. [Example 1] Post-chlorinated vinyl chloride 100 parts by weight Flake graphite powder 200 〃 Lead steering acid (stabilizer) 5 〃 DOP (plasticizer) 10 〃 [Example 2] Post-chlorinated vinyl chloride 100 parts by weight Polymethyl Methacrylate 5 Scale graphite powder 150 Lead stearate 2 DOP 10 [Example 3] Post-chlorinated vinyl chloride 100 parts by weight IIR 10 Scale graphite powder 200 Lead stearate 2 DOP 10 [ Example 4] Post-chlorinated vinyl chloride 100 parts by weight polymethyl methacrylate 5 〃 IIR 10 〃 Flake graphite powder 150 〃 Lead stearate 2 〃 DOP 10 〃 [Comparative example] Vinyl chloride resin 100 parts by weight Flake graphite powder 200 〃 Stearic acid Lead 5 〃 DOP 10 〃 Each powder is heated in a kneader at 150 to 160℃ with the above blending ratio.
The mixture was kneaded under heating to obtain a kneaded product. In addition, in order to obtain a blend of graphite, the above-mentioned kneaded material was passed through rollers many times to obtain a sheet material. The physical properties of these materials are shown in the table below.

【table】

[Table] Next, various audio equipment casings were molded using the materials of the above examples. That is, a speaker cabinet, a player housing, and a radio cassette case were manufactured by press molding using the materials of each example, with and without oriented graphite powder. Each of the audio equipment casings obtained above has a material composition mainly composed of synthetic resin and graphite powder, so it has a low density and is lightweight. In the case of the one with added material, it was larger due to its softness. Furthermore, the oriented graphite powder has high elasticity and rigidity, and therefore can be constructed with high internal loss while maintaining strength. Furthermore, we measured the heat resistance of each of the above casings and found that it was approximately 120℃.
No deformation occurred even under heating.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of the kneaded material used for molding the audio equipment casing of the invention, FIG. 2 is a process diagram showing an example of molding the audio equipment casing of the invention, and FIGS.
b and c are perspective views of a speaker cabinet, a player housing, and a radio cassette case, respectively, according to an embodiment of the present invention, and FIG. 5 is a perspective view of a plate obtained by laminating the same sheet materials, FIG. 6 is an exploded perspective view of a speaker cabinet according to an embodiment of the present invention, and FIG. 7 is a perspective view of a speaker cabinet according to an embodiment of the present invention. FIG. 2 is a perspective view of a player housing according to an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Resin material, 2... Scale-like graphite powder, 3... Kneading material, 7... Speaker cabinet, 8... Player housing, 9... Radio cassette case, 10...
sheet material.

Claims (1)

[Scope of Claims] 1. A casing for an audio device formed of a kneaded material whose main components are post-chlorinated vinyl chloride and flaky graphite powder. 2. A housing for audio equipment, characterized in that it is formed of a kneaded material containing post-chlorinated vinyl chloride and flaky graphite powder as a main component, and the flaky graphite powder is oriented along the surface. 3. A casing for an audio device made of a kneaded material whose main components are post-chlorinated vinyl chloride, polymethyl methacrylate, and scaly black powder. 4. A casing for audio equipment formed of a kneaded material containing post-chlorinated vinyl chloride, polymethyl methacrylate, and flaky graphite powder as main components, and characterized in that the flaky graphite powder is oriented along the surface. . 5. A housing for audio equipment formed of a kneaded material containing post-chlorinated vinyl chloride, a rubber material, and flaky graphite powder as main components. 6. A casing for audio equipment formed of a kneaded material mainly composed of post-chlorinated vinyl chloride, a rubber material, and flaky graphite powder, and characterized in that the flaky graphite powder is oriented along the surface. . 7. A housing for audio equipment formed of a kneaded material whose main components are post-chlorinated vinyl chloride, polymethyl methacrylate, a rubber material, and flaky graphite powder. 8. An acoustic device formed of a kneaded material mainly composed of post-chlorinated vinyl chloride, polymethyl methacrylate, a rubber material, and flaky graphite powder, and characterized in that the flaky graphite powder is oriented along the surface. Equipment housing.