JP2009065477A - Damping material for speaker edge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a damping material for a speaker edge which has extremely large internal loss and is excellent in durability, and the speaker edge. <P>SOLUTION: The damping material for the speaker edge contains a component (A) which is the triblock copolymer of polystyrene polyisobutene-polystyrene and a component (B) which is polyolefine, and the speaker edge is obtained by molding the damping material for the speaker edge. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a speaker edge damping material and a speaker edge having a very large internal loss and high durability.

  The speaker diaphragm is supported by speaker edges. Such a speaker edge is required to have a high internal loss so as to be able to absorb excessive vibration of the diaphragm. As a material therefor, an ethylene-acrylate copolymer rubber (see Patent Document 1) has been used so far. ), Polyurethane foams (for example, see Patent Document 2), thermoplastic elastomers mainly composed of a mixture of a styrenic thermoplastic elastomer and polypropylene (for example, see Patent Document 3), and the like have been developed. Further, as a vibration isolator, for example, a vibration isolator having a low hardness and excellent durability, which contains a polystyrene-polybutadiene-polystyrene triblock copolymer, polypropylene, and paraffinic oil (for example, patents) is known. Reference 4).

Japanese Patent Laid-Open No. 08-275288 Japanese Patent Laid-Open No. 08-033095 JP 2004-269756 A JP 2000-169826 A

  However, the material described in Patent Document 1 has a problem that it lacks flexibility. The material described in Patent Document 2 is a foam, and the foam usually has a large dimensional change at the time of sound output compared to other materials, so that it has poor durability and cannot withstand long-term use as a speaker edge. is there. In the material described in Patent Document 3, the internal loss (Tan δ) at 25 ° C. is 0.09 to 0.29, and although it has a good internal loss depending on the blending conditions, it cannot be said to be an extremely excellent value. There is room for improvement. Moreover, although patent document 4 describes the material excellent as a vibration isolator, there is no description about an internal loss at all. Then, when the present inventors prepared several types of samples containing the compounding ingredients described in Patent Document 4 and measured their internal losses (see Comparative Examples 1 to 5 in the present specification), good internal losses were obtained. However, it was not an extremely excellent value, and it was found that there was room for further improvement.

  As a result of intensive studies on the vibration damping material for speaker edge, the present inventors have paid attention to the above problems, and as a result, a speaker containing component (A) polystyrene-polyisobutene-polystyrene triblock copolymer and component (B) polyolefin. The edge damping material has been found to have a very large internal loss and excellent durability, and the present invention has been completed.

That is, the present invention
[1] A vibration damping material for speaker edge, comprising: component (A) polystyrene-polyisobutene-polystyrene triblock copolymer (hereinafter abbreviated as SIBS) and component (B) polyolefin;
[2] The vibration damping material for speaker edge according to [1], wherein the content of the component (B) is 5 to 50 parts by mass with respect to 100 parts by mass of the component (A),
[3] The vibration damping material for speaker edge according to [1] or [2], further comprising component (C) polybutene,
[4] The vibration damping material for speaker edge according to [3], wherein the content of the component (C) is 70 parts by mass or less with respect to 100 parts by mass of the component (A).
[5] The vibration damping material for speaker edge according to any one of [1] to [4], wherein the component (B) polyolefin is polypropylene,
[6] A speaker edge obtained by molding the vibration damping material for a speaker edge according to [1] to [5],
Is to provide.

  According to the present invention, it is possible to obtain a speaker edge damping material having a very large internal loss and excellent durability. For example, a speaker edge for a speaker that needs to output a large volume constantly is provided. Can be provided. When a speaker made using such a speaker edge is used, distortion of sound can be sufficiently suppressed, and even at a large volume, a good sound quality can be provided over a long period of time compared to a conventional speaker edge.

  The vibration damping material for speaker edge of the present invention contains component (A) SIBS and component (B) polyolefin.

First, the component (A) will be described.
Although there is no restriction | limiting in particular as SIBS, Preferably the content rate of a polystyrene block is 10-70 mass%, More preferably, it is 20-40 mass%. Moreover, although there is no restriction | limiting in particular in a weight average molecular weight, It is preferable that it is 40000-120,000, and it is more preferable that it is 60000-100,000. There is no restriction | limiting in particular about the manufacturing method of this SIBS, A conventionally well-known method can be used. SIBS is commercially available. For example, “SIBSTAR (registered trademark) 073T” (manufactured by Kaneka Corporation, weight average molecular weight 70000, polystyrene block content 30%), “SIBSTAR (registered trademark) 103T” (manufactured by Kaneka Corporation). , Weight average molecular weight 100,000, polystyrene block content 30%), etc., and these may be used. The weight average molecular weight was determined by gel permeation chromatography [GPC: Tosoh HLC-8020, column: Tosoh GMH-XL (two in series), detector: differential refractometer (RI)]. As a reference, it is a value obtained in terms of polystyrene of each polymer, and the same applies hereinafter.

The component (B) polyolefin used in the present invention is a homopolymer or copolymer excluding polybutene, such as polyethylene, polypropylene, ethylene / propylene copolymer, propylene / 4-methyl-1-pentene copolymer, And poly (4-methyl-1-pentene). Among these, from the viewpoint of workability and heat resistance, the melt flow rate (hereinafter abbreviated as MFR) measured according to JIS K7210 [190 ° C., 21.18N (2.16 kgf)] is 0.1 to 100 g. It is preferable to use a polyolefin that is / 10 minutes, and it is more preferable to use a polyolefin that is 0.5 to 50 g / 10 minutes. Moreover, it is preferable that it is a polypropylene. Polyolefins are commercially available. For example, “NOVATEC (registered trademark) BC05B” (trade name, component; polypropylene, manufactured by Nippon Polypro Co., Ltd.), “Prime Polypro H-700” (trade name, component: polypropylene, Co., Ltd.) Prime polymer), “M1600” (trade name, component; polypropylene, manufactured by Sun Allomer Co., Ltd.), etc., and these may be used.
Content of a component (B) polyolefin is 5-50 mass parts with respect to 100 mass parts of component (A), and it is preferable that it is 5-20 mass parts from a viewpoint of workability.

  Polystyrene can be used in combination with the component (B) polyolefin for the purpose of improving processability and heat resistance. As the polystyrene, those obtained by a known production method can be used, and the polystyrene may be produced by any one of a radical polymerization method and an ionic polymerization method. The weight average molecular weight of the polystyrene is preferably 5,000 to 500,000, more preferably 10,000 to 200,000, and the molecular weight distribution is preferably 5 or less. Examples of the polystyrene include polystyrene, a styrene-butadiene block copolymer having a styrene unit content of 60% by mass or more, rubber-reinforced polystyrene, poly α-methylstyrene, polypt-butylstyrene, and the like. 1 type may be used independently and 2 or more types may be used together. When using polystyrene together, it is preferable that polyolefin / polystyrene = 95/5 to 85/15 (mass ratio).

In producing the speaker edge of the present invention, the component (C) polybutene can be contained in addition to the components (A) and (B). The component (C) polybutene is not particularly limited, and may be n-butene or isobutene, or may be an isobutene / n-butene copolymer based on isobutene. The weight average molecular weight of a component (C) polybutene becomes like this. Preferably it is 300-3000, More preferably, it is 900-2000. There is no restriction | limiting in particular in the manufacturing method of this component (C) polybutene, A well-known manufacturing method can be utilized, You may manufacture by any method of a radical polymerization method or an ionic polymerization method. The component (C) is commercially available, for example, “Nisseki Polybutene HV-300” (trade name, component; copolymer of isobutene and n-butene mainly composed of isobutene, manufactured by Nippon Oil Corporation, Weight average molecular weight 1400), “Nisseki Polybutene HV-100” (trade name, manufactured by Nippon Oil Corporation, weight average molecular weight 980), “Nisseki Polybutene HV-1900” (trade name, manufactured by Nippon Oil Corporation) Weight average molecular weight 2900), etc., and these may be used. Among these, it is preferable to use “Nisseki Polybutene HV-300” from the viewpoint of processability and safety during processing.
By including such a component (C), the plasticity of the vibration damping material for speaker edge is increased and the internal loss is improved. When the component (C) is contained, the content is not particularly limited, but is preferably 70 parts by mass or less, more preferably 15 to 35 parts by mass with respect to 100 parts by mass of the component (A). .

In addition to the components (A) to (C), other additives may be added to the speaker edge damping material of the present invention as long as the object of the present invention is not impaired. Examples of such additives include ceramic, carbon black, amber, senna, kaolin, nickel titanium yellow, cobalt blue, plamaster gray, quinophthalone, diketopyrrolopyrrole, quinacridone, dioxazine, phthalocyanine blue, and phthalocyanine green. Flame retardant: Anti-aging agent: Antistatic agent: Antibacterial agent: Antioxidant: Inorganic hollow fillers such as talc, silica, calcium carbonate, magnesium carbonate, aluminum hydroxide, barium sulfate, glass fiber, glass powder, glass balloon, ceramic powder Inorganic fillers such as mica, organic fillers such as cork powder, wood powder and graphite: Release agents such as stearic acid: Light stabilizers: Tackifiers such as rosin derivatives (tackfire): “Rheostomer® ) B Adhesive elastomers such as (trade name, manufactured by Riken Technos Co., Ltd.): PW380 (trade name, manufactured by Idemitsu Kosan Co., Ltd.), “Lucanto (registered trademark) HC-180” (trade name, manufactured by Mitsui Chemicals, Inc.) Plant oils such as paraffinic oil, naphthenic oil, silicone oil, aromatic oil, castor oil, cottonseed oil, linseed oil, rapeseed oil, soybean oil, palm oil, palm oil, peanut oil, wax, pine oil, olive oil And processing aids such as ester plasticizers. When the additive is added, the amount used is preferably 20 parts by mass or less, and more preferably 5 parts by mass or less with respect to 100 parts by mass of the component (A).
In addition, it is preferable that the vibration damping material for speaker edge of the present invention does not contain a crosslinking agent so as not to deteriorate the acoustic characteristics of the speaker edge.

  Thus, the vibration damping material for speaker edge of the present invention can be obtained by mixing component (A) SIBS and component (B) polyolefin, and optionally component (C) polybutene and the above additives. Although there is no particular limitation on the mixing method, for example, by using a single-screw kneader, a twin-screw kneader, a Banbury mixer, a Brabender, a kneader, a high shear mixer, preferably by melt-kneading at 100 to 300 ° C, A vibration damping material for speaker edge can be obtained.

  The speaker edge damping material obtained as described above can be formed into a sheet shape by a known method, for example, a T-die extruder, and then the speaker edge can be produced by secondary molding using a heating mold. . Moreover, a speaker edge can also be directly manufactured by injection molding instead of extrusion molding.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.

<Examples 1-5, Comparative Examples 1-5>
Each component is mixed in advance with the formulation shown in Table 1 (unit: parts by mass), and then a twin-screw kneader (manufactured by Toshiba Machine Co., Ltd., TEM58BS type, screw full length / cylinder diameter = 62.5, kneading zone for the screw full length) (Length ratio = 62%) and kneaded at 180 ° C., and cut with a cutter while extruding into a strand shape, to obtain a pellet-shaped vibration damping material for speaker edge. The breaking strength and internal loss (Tanδ) of the obtained speaker edge damping material were measured as follows and are shown in Table 1.

(1) Breaking strength Based on JIS K6251: 2004, the tensile stress at the time of cutting the dumbbell-shaped No. 3 sample at 23 ° C. was defined as the breaking strength (MPa).
(2) Internal loss (Tanδ)
A sheet having a length of 40 mm, a width of 5 mm, and a thickness of 2 mm was prepared and used as a sample. For this sample, a viscoelastic spectrometer “RDAIII” (manufactured by Rheometric Scientific F.E.) was used, the distance between chucks was 10 mm, the dynamic strain was 1%, the frequency was 60 Hz, and the measurement temperature was −30 to 100 ° C. Under the measurement conditions, dynamic viscoelasticity measurement was performed, and the internal loss (loss tangent) at the temperatures shown in Table 1 was measured.

^{* 1} : Kaneka Corporation, weight average molecular weight 70000,
Polystyrene block content 30%
^{* 2} : Kuraray Co., Ltd., triblock copolymer consisting of polystyrene-hydrogenated butadiene / isoprene copolymer-polystyrene, weight average molecular weight of about 300,000, polystyrene block content of 30%
^{* 3} : manufactured by Asahi Kasei Chemicals Corporation, triblock copolymer made of polystyrene-hydrogenated polybutadiene-polystyrene, weight average molecular weight 60000, polystyrene block content 30%
^{* 4} : MFR50 (g / 10 min), manufactured by Nippon Polypro Co., Ltd.
^{* 5} : MFR30 (g / 10 min), manufactured by Sun Allomer Co., Ltd.
^{* 6} : Made by Prime Polymer Co., Ltd.
^{* 7} : Component: copolymer of isobutene and n-butene mainly composed of isobutene,
Weight average molecular weight 1400, manufactured by Nippon Oil Corporation
^{* 8} : Asahi Kasei Chemicals Corporation
^{* 9} : Paraffinic oil, molecular weight 750, manufactured by Idemitsu Kosan Co., Ltd.
^{* 10} : Paraffinic oil, molecular weight 1500, manufactured by Mitsui Chemicals, Inc.
^{* 11} : SH200-100cs (trade name), manufactured by Toray Dow Corning Co., Ltd.
^{* 12} : Made by Cytec Japan
^{* 13} : Ciba Specialty Chemicals Co., Ltd.
^{* 14} : Dainippon Ink & Chemicals, Inc.

  As shown in Table 1, in Comparative Examples 1-5, it turns out that all have low fracture strength and are insufficient in durability. It can also be seen that although the internal loss is good, it is not remarkably excellent. On the other hand, in Examples 1-5, it turns out that internal loss is very high, and also fracture strength is large compared with Comparative Examples 1-5, and it is excellent in durability.

  The speaker edge damping material of the present invention has a very large internal loss and is excellent in durability. For example, a speaker edge for a speaker that is used in a concert or the like and needs to output a large volume constantly. Is available as

Claims (6)

  A vibration damping material for a speaker edge, comprising a component (A) a polystyrene-polyisobutene-polystyrene triblock copolymer and a component (B) a polyolefin.   The damping material for speaker edges according to claim 1, wherein the content of the component (B) is 5 to 50 parts by mass with respect to 100 parts by mass of the component (A).   Furthermore, the damping material for speaker edges of Claim 1 or 2 containing a component (C) polybutene.   The vibration damping material for speaker edge according to claim 3, wherein the content of the component (C) is 70 parts by mass or less with respect to 100 parts by mass of the component (A).   The vibration damping material for speaker edge according to any one of claims 1 to 4, wherein the component (B) polyolefin is polypropylene.   The speaker edge obtained by shape | molding the damping material for speaker edges of Claims 1-5.