JP3145546B2 - Edge for speaker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an edge for a loudspeaker, and more particularly to an edge for a loudspeaker capable of sufficiently exhibiting responsiveness and vibration absorbing characteristics and shortening a manufacturing time.

[0002]

2. Description of the Related Art In a so-called cone type speaker, an annular edge formed of a rubber elastic body is fixed to a peripheral portion of the cone. This speaker edge is required to be able to radiate the vibration of the vibrator as a sound wave with high responsiveness. Furthermore, the speaker edge can exhibit a sufficient vibration damping function so that the previous vibration does not affect the next transmitted vibration in a state where the vibration of the vibrator is continuously transmitted to the edge. thing,
That is, a large loss coefficient is required.

[0003] However, in order to satisfy the high response, the material needs to have a property close to a rigid body.
Conversely, to increase the loss factor, the material must have sufficient viscosity. In other words, the material of the edge for the speaker needs to be provided with two contradictory performances.
There is a problem that the performance of the other cannot be sufficiently ensured.

Conventionally, there has been a speaker edge using a rubber elastic body. For example, a speaker edge formed by molding a rubber material containing butyl rubber as a main component is known (see, for example, Japanese Patent Laid-Open Publication No. HEI 9-157556). 52-1722
No. 7). However, when a speaker edge is formed from a rubber elastic body, a vulcanization step is indispensable in order to promote a reaction or to maintain a predetermined shape as an edge. In the vulcanization process, it is necessary to mix various compounding agents such as vulcanizing agents and vulcanization accelerators under highly accurate compounding conditions, and to perform heating and pressing for a long time in a vulcanizing device. In addition, there is a problem that time and economic disadvantages are inevitable, and the work environment is polluted. In addition, Japanese Utility Model Application Laid-Open No. 54-108029 discloses
Is obtained by copolymerizing polystyrene and polyolefin.
Made of an elastomer of ABA type copolymer
A peaker edge is disclosed. This prior art includes:
Polybutadiene or polyisop as polyolefin
Is described, but this elastomer
The peaker edge has a lower loss factor (ta) than the prior art.
n-δ) is excellent .

[0005]

SUMMARY OF THE INVENTION Therefore, an object of the present invention, the prior art
It is an object of the present invention to provide a speaker edge having excellent accuracy which can exhibit higher responsiveness and higher vibration absorption characteristics than that of a speaker, and which can be formed in a reduced work process.

[0006]

Means for Solving the Problems The present invention has been proposed to achieve the above object, and has the following structure. That is, according to the present invention, a segment capable of imparting a function as a viscous body,
Ethylene-acetic acid is added to a thermoplastic elastomer which is a block copolymer with a segment capable of imparting a function close to a rigid body.
Vinyl copolymer or polybutene, butyl rubber and rubber
Eras selected from the group consisting of tylene-butadiene rubber
An edge for a speaker characterized by being molded from a composition containing a tomer is provided.

[0007]

Technical characteristics of the DETAILED DESCRIPTION OF THE INVENTION The present invention, speaker edge, not the rubber elastic body vulcanization process essential for expression of the physical properties, the vulcanization process is unnecessary thermoplastic elastomers, further ethylene -Vinyl acetate copolymer or polybutene
In that the thermoplastic elastomer has a segment capable of exhibiting a function as a viscous body (hereinafter referred to as a soft segment) and a function close to a rigid body. It consists of a block copolymer with a segment that can be exhibited (hereinafter referred to as a hard segment).

Namely, speaker edges, by having a soft segment, it is possible to exhibit a sufficient viscosity, and so can exhibit also a function close to a rigid body by having a hard segment, this error
Mixing Tylene-vinyl acetate copolymer or polybutene
Edge for a speaker of the present invention molded from the composition
It has both the characteristic of sufficiently attenuating vibration and the characteristic of transmitting vibration better than the conventional technology .

In the present invention, the segment capable of imparting a function as a viscous body means a segment belonging to at least one of the following categories.
The degree to which a segment can freely rotate around its bond (hereinafter referred to as the degree of freedom of rotation) is high, and the interaction between molecules is low.

In the present invention, the segment capable of imparting a function close to a rigid body means a segment belonging to at least one of the following categories. It has a low degree of freedom of rotation, a large steric hindrance, a side chain with a somewhat long chain length, and a terminal end with a large atomic radius such as halogen. In the present invention, the term “segment” refers to a unit that forms a part of the block copolymer and has common characteristics.

Examples of the hard segment include polystyrene and polyvinyl chloride, and polystyrene is particularly preferred. Examples of the soft segment include vinyl polyisoprene, polyisoprene, and the like, with vinyl polyisoprene being particularly preferred. Further, the thermoplastic elastomer in the present invention means a polymer substance which exhibits melting and softening upon heating and exhibits plasticity and exhibits rubber elasticity at around normal temperature.

The polymer of the present invention may contain known additives such as a foaming agent, a crosslinking agent, a filler, and a softener. Silicone can be used as a foaming agent, DCP (dicumyl peroxide) can be used as a crosslinking agent, mica can be used as a filler, and DOP (dioctyl phthalate) can be used as a softener.

[0013]

(1) According to the present invention, high responsiveness and high vibration absorption characteristics can be exhibited, and a vulcanizing step is not required. Edge can be provided. (2) Further, in the present invention, the speaker edge is formed of a thermoplastic elastomer instead of rubber.
Since the molding material can be supplied as pellets, an almost unmanned molding process in which a working robot is arranged can be realized. Therefore, the productivity of the speaker edge can be improved, and the manufacturing cost can be reduced.

[0014]

The present invention will be described below by way of examples. Comparative Example 1 A triblock copolymer composed of polystyrene and vinyl-polyisoprene having a styrene content of 20% and a vinyl bond content of 55% was injection-molded under the conditions of a cylinder temperature of 220 ° C. and a mold temperature of 40 ° C. An edge for a speaker, which is a copolymer, was obtained. Table 1 shows the loss coefficients of the obtained speaker edges.

EXAMPLE 1 5 parts by weight of azodicarbonamide (blowing agent) and 85 parts by weight of a block copolymer having the same composition as in Comparative Example 1 were used.
0.8 parts by weight of a CP (crosslinking agent), 110 parts by weight of calcium carbonate, 1 part by weight of stearic acid, and 15 parts by weight of an EVA resin were mixed. This mixture was kneaded with a roll at a temperature of 115 ° C. to obtain a batch.
Press molding was performed at 70 ° C. for 10 minutes to form a foam. Next, the foam was sliced into a predetermined thickness and punched into a predetermined shape by a press to obtain a speaker edge. Table 1 shows the loss coefficient of the speaker edge.

Example 2 30 parts by weight of polybutene was mixed with 100 parts by weight of a block copolymer having the same composition as in Comparative Example 1, and the mixture was kneaded at a barrel temperature of 200 ° C. using a twin-screw extruder. Then
Pellets were obtained with a pulverizer, and the pellets were injection-molded under the conditions of a cylinder temperature of 220 ° C. and a mold temperature of 40 ° C. to obtain a speaker edge. Table 1 shows the loss coefficient of this edge. In addition, in Example 3, polybutene is added to the block copolymer, but an elastomer such as butyl rubber or styrene-butadiene rubber may be added instead to obtain desired temperature characteristics. The addition amount depends on the required temperature characteristics, but is preferably 50 phr or less.

Comparative Example 2 50 parts by weight of carbon, 10 parts by weight of a softener, and 1 part by weight of sulfur were kneaded with 100 parts by weight of styrene-butadiene rubber by a roll, and the mixture was vulcanized at 170 ° C. for 10 minutes by a press. Thus, a speaker edge was obtained. Table 1 shows the loss coefficients of the obtained speaker edges.

[0018]

[Table 1] As shown in Table 1 above, the loss of Example 1 and Example 2
The coefficients are all larger than the loss coefficients of Comparative Examples 1 and 2 , and it is clear that they are excellent as speaker edges. In addition, the value of each column of the loss coefficient in Table 1 has shown the value in 25 degreeC.

[Brief description of the drawings]

FIG. 1 is a diagram showing a frequency characteristic curve of a speaker in which a speaker edge according to the present invention is used, where symbol A indicates the frequency characteristic of the edge according to the present invention, and symbol B indicates the frequency characteristic of the conventional edge. Is shown.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H04R 7/20 C08L 53/00

Claims (2)

(57) [Claims] 1. A thermoplastic elastomer, which is a block copolymer of a segment (soft segment) capable of exhibiting a function as a viscous material and a segment (hard segment) capable of exhibiting a function close to a rigid body, is provided with ethylene-acetic acid. Bi
Nyl copolymer or polybutene, butyl rubber and stainless steel
Elast selected from the group consisting of len-butadiene rubber
An edge for a speaker, which is molded from a composition containing a polymer. 2. The loudspeaker edge according to claim 1, wherein the thermoplastic elastomer is a block copolymer whose soft segment is made of vinyl-polyisoprene and whose hard segment is made of polystyrene.