JP2549866B2 - Support member for diaphragm for electroacoustic transducer - Google Patents

Description

TECHNICAL FIELD The present invention relates to an improvement of a support member such as an edge or a damper for elastically supporting a diaphragm for an electroacoustic transducer.

[Prior Art] This type of support member will be described, for example, for a speaker diaphragm edge. After a cotton cloth or the like is impregnated with a thermosetting resin, a viscoelastic material such as rubber is coated to form a predetermined edge shape. Edge of coated cloth heat-molded on urethane foamed urethane edge formed by heat-molding urethane foam sheet into a predetermined edge shape was often used.

[Problems to be Solved by the Invention] The above-mentioned conventional edge has various unsatisfactory points. For example, the linearity of the input-displacement characteristic is not good because the elasticity of the material itself is insufficient. Further, since the coating amount of the viscoelastic material is limited due to the increase in weight due to the coating layer, the internal loss cannot be substantially obtained, and the damping effect of the high frequency resonance is poor, and it is difficult to obtain a flat frequency characteristic. I have a problem.

Further, the stretchability of the edge is better than that of the above-mentioned edge, but it has the same problem as the edge with insufficient internal loss, and further, the light resistance is poor and the physical properties are significantly deteriorated by light, especially ultraviolet rays. There was a problem.

[Means for Solving the Problem] The present invention relates to a thermoplastic resin having a two-layer structure in which a supporting member of a diaphragm for an electroacoustic transducer has a two-layer structure in which a polypropylene resin microdomain layer is dispersed in an ethylene-propylene-diene-methylene linkage rubber matrix. It is composed of an olefin elastomer.

[Operation] An electroacoustic transducer that can ideally support the diaphragm because of the sufficient internal loss due to the above-mentioned support member, the good light resistance and the good heat resistance, the frequency characteristics are good, and the secular change is small. Could be provided.

[Examples] Hereinafter, the present invention will be described with reference to Examples.

Thermoplastic olefin elastomer (Monsanto USA)
201-80) was extruded into a sheet having a thickness of 0.3 mm, and the sheet was further vacuum formed on the roll edge.

The thermoplastic olefin elastomer used in this example will be described below. This thermoplastic olefin elastomer (201-80, manufactured by Monsanto, USA) is a soft segment of a low glass transition point component that exhibits rubber elasticity, ethylene-propylene-. Diene-methylene linkage rubber (the structural formula is shown below) And a polypropylene resin that is a hard segment of a high glass transition point component that flows at high temperature but prevents plastic deformation at normal temperature (the structural formula is shown below) Are mainly used as raw materials, and these are melt-kneaded to completely cross-link the ethylene-propylene-diene-methylene linkage rubber.

The macrostructure of the thermoplastic olefin elastomer of this example has a two-layer structure in which microdomains (fine constraint layers) of polypropylene resin are dispersed in an ethylene-propylene-diene-methylene linkage rubber matrix, and the soft segment The fine ethylene-propylene-diene-methylene linkage rubber particles of the component are completely crosslinked and the spaces between them are restrained by the polypropylene resin, so that they have high internal loss, rubber elasticity, and excellent light resistance and heat resistance.

Next, as a comparative example, urethane foam (thickness: 6 mm) was formed in the same shape to obtain a roll edge.

[Effect of the Invention] When the internal loss of each edge was measured by the vibration lead method, the value was 0.21 for the comparative example edge, whereas it was 0.21 for the comparative example edge.

In addition, when the irradiation time required for the tensile strength value to decrease by 10% was measured in a light deterioration test using a xenon fade meter (black panel temperature 60 ° C, humidity 90% RH), it was 200 hours in the comparative example. On the other hand, it was 600 hours in the example.

Therefore, if the edge of the embodiment of the present invention is adopted, the internal loss is large, so that the peak of high frequency resonance is alleviated and a flatter frequency characteristic is obtained.

Furthermore, the light resistance was improved, and as a result, the deterioration of properties due to aging was reduced.

Claims (1)

(57) [Claims] 1. A support member for elastically supporting a diaphragm for an electroacoustic transducer, the support member having a two-layer structure in which microdomain layers of polypropylene resin are dispersed in an ethylene-propylene-diene-methylene linkage rubber matrix. A support member for a diaphragm for an electroacoustic transducer, which is formed of a plastic olefin elastomer.