JP2731260B2 - Multilayer speaker diaphragm - Google Patents

Description

The present invention relates to a speaker diaphragm represented by a speaker cone or the like.

[Conventional technology]

Conventionally, as a material for the speaker cone, paper or a polyolefin-based polymer film and a material in which an inorganic material is mixed therein have been used in many cases.
57-154994, JP-A-62-205127, JP-A-62
As seen in JP-149296, JP-A-62-101281, liquid crystal films have begun to be used.

[Problems to be solved by the invention]

However, speaker cones using paper or a polyolefin-based polymer film have the advantage of high internal loss tanδ and low price, but paper and polyolefin have specific elastic modulus E / ρ (E is elastic modulus, ρ is density ), The balance of performance as a speaker cone is insufficient. For this reason, inorganic materials for paper and polyolefin,
In particular, a method of increasing the specific elastic modulus by mixing mica and carbon fiber has been carried out, but the amount of inorganic material mixed is limited, and at present the specific elastic modulus is not sufficiently satisfactory. is there. Further, polyolefin is disadvantageous in terms of heat resistance and is not suitable for car stereos or high-output speakers.
In the case of a speaker diaphragm using a liquid crystal polymer, although a high specific elastic modulus, internal loss, and heat resistance can be obtained, the liquid crystal polymer is expensive, and has a highly anisotropic and heterogeneous structure. A satisfactory speaker cone cannot be obtained.

The present invention has been made in order to solve such a problem, and an object of the present invention is to obtain a speaker diaphragm having both high heat resistance and an appropriate specific elastic modulus, internal loss, and economy.

[Means for solving the problem]

That is, the present invention relates to polyethylene terephthalate 10
A layer of a resin composition in which (a) 5 to 50 parts by weight of an inorganic compound having an average particle size of 50 μ or less and (b) 0.5 to 10 parts by weight of an inorganic compound or polyolefin having an average particle size of 10 μ or less with respect to 0 part by weight. And a sheet in which a layer of a polyester resin other than polyethylene terephthalate is disposed in an intermediate layer between the layer and a layer of a thermoplastic polyester elastomer.

As the polyethylene terephthalate used in the present invention, in addition to terephthalic acid or an alkyl ester derivative of terephthalic acid and ethylene glycol, isophthalic acid, naphthalenedicarboxylic acid, diphenyl ether dicarboxylic acid, diphenyl metadicarboxylic acid, diphenyl sulfone are used as copolymerization components. Dicarboxylic acid, p-
(2-hydroxyethoxy) benzoic acid, 5-sodium sulfoisophthalic acid, adipic acid, azelaic acid, sebacic acid, dodecane-1,12-dicarboxylic acid, tetradecane-1,14-dicarboxylic acid, hexadecane-1,16-dicarboxylic acid Acids, octadecane-1,18-dicarboxylic acid, dicarboxylic acid components such as 6-ethyl-hexadecane-1,16-dicarboxylic acid, propylene glycol, diethylene glycol,
A glycol component such as polyalkylene glycol such as butylene glycol, pentyl glycol, neopentyl glycol, hexamethylene glycol, polyethylene glycol and polytetramethylene glycol may be contained, and 80% by mole or more of the repeating unit constituting ethylene component is ethylene. It is made of terephthalate.

The inorganic compound used as the component (A) of the present invention includes:
Depending on the particle size and shape, the sheet surface smoothener, reinforcing agent,
The effect as an anisotropic moderator of mechanical properties and a crystal nucleating agent is different. When the average particle size exceeds about 50μ, the effect is reduced, so that an inorganic compound having an average particle size of 50μ or less is generally useful.

Specific examples of the inorganic compound having an average particle size of 50μ or less include carbon black, silica, calcium carbonate, synthetic silicic acid and silicate, zinc white, halocytoclay, kaolin, basic magnesium carbonate, mica, talc, quartz powder, Wollastonite, dolomite powder, titanium oxide, barium sulfate, calcium sulfate, alumina and the like,
One or more of these inorganic compounds can be used. Among them, talc, mica and wollastonite are particularly effective in the present invention.

Examples of the inorganic compound having an average particle size of 10 μm or less used as the component (b) of the present invention include talc, calcium carbonate, wollastonite and the like, and talc is particularly effective in the present invention. (B) As components,
Instead of the above, polyolefins are also very effective,
There is an advantage that not only the crystallization is promoted but also the impact resistance is improved. As the polyolefin, polyethylene such as low-density polyethylene (LDPE), high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE), polypropylene (pp), and modified polyolefins such as maleic anhydride graft-modified thereof can be used. .

It is also possible to use an inorganic compound having an average particle size of 10 μm or less in combination with a polyolefin.

About the mixing ratio of each component in the resin composition of the present invention,
If the component (a), that is, the inorganic compound having an average particle size of 50 μm or less, is less than 5 parts by weight based on 100 parts by weight of the polyester component, it may be used as a surface smoothing agent for a sheet, an anisotropic agent for mechanical properties, or a reinforcing material. The effect is insufficient, and conversely, if it is more than 50 parts by weight, the mechanical properties are significantly deteriorated.
Therefore, the compounding amount of the component (a) is 10% of the polyester component.
0 to 5 parts by weight, preferably 10 to 3 parts by weight.
0 parts by weight.

The component (b), that is, thermoplastic polyester 100
If the amount of the inorganic compound or polyolefin having an average particle size of 10 μm or less with respect to parts by weight does not reach 0.5 parts by weight, the increase in crystallinity is slow, and the problem of economical processing occurs. On the other hand, the rate of increase in crystallinity is saturated even if blended in excess of 10 parts by weight, and the mechanical properties start to decrease, so the average particle size blended with respect to 100 parts by weight of the thermoplastic polyester is 10 μ or less. The amount of the inorganic compound or polyolefin is 0.5 to 10 parts by weight, preferably 1 to 5 parts by weight.

The resin composition of the present invention may further contain additives such as a heat stabilizer, an oxidation stabilizer, a light stabilizer, a lubricant, a pigment, a flame retardant, and a plasticizer, if necessary.

As the thermoplastic polyester elastomer used in the present invention, the hard segment is an aromatic polyester,
A polyester-polyether type elastomer whose soft segment is composed of an aliphatic polyether, and a polyester-polyester type elastomer whose hard segment is composed of an aromatic polyester and whose soft segment is composed of an aliphatic polyester can be used.

Examples of the polyester resin used in the present invention include polybutylene terephthalate, 1,4-cyclohexanemethylene terephthalate, polyarylate mainly composed of bisphenol A and polycarbonate, parahydroxybenzoic acid and 2,6 naphthalenedicarboxylic acid. And a copolymer resin composition containing 40% or more thereof.

In the present invention, the weight ratio of the polyethylene terephthalate resin to the thermoplastic polyester elastomer and the polyester resin is from 40 to 94: 3 to 30: 3 to 30, preferably from 60 to 90: 5 to 20: 5 to 20. Further, as a method for producing a multilayer sheet in the present invention, a method of coextruding three components using a multilayer die and forming a film is more advantageous in terms of production cost and the like, but it can also be produced by a method such as extrusion lamination.

〔Example〕

Next, the present invention will be specifically described with reference to examples. In the following examples, parts show parts by weight.

Example 1 A pellet made by melting and kneading 30 parts of mica having an average particle diameter of 40 μm and 3 parts of LLDPE (LX529, Mitsubishi Yuka Co., Ltd.) with 100 parts of polyethylene terephthalate resin having an intrinsic viscosity of 1.0 using a twin screw extruder, and polyester Extrude a thermoplastic elastomer (Dai-Pont Toray Dutyre Co., Ltd., Hytrel 4047) and a liquid crystal polyester (Unitika Co., Ltd., Rodrun LC-5000) using three dedicated extruders from a multilayer die,
PET resin composition (125μ) / Liquid crystal polyester (10μ) /
Elastomer (30μ) / Liquid crystal polyester (10μ) / PET
A 300 μm thick sheet having a five-layer configuration of the resin composition (125 μm) was produced. The obtained sheet is formed into a vacuum / pressurized air (plug assist) molding machine (Asano Laboratory Co., Ltd., FLPD-141-WH-2)
At 0, the sheet was preheated to 140 ° C and the speaker diaphragm was formed at a metal temperature of 170 ° C and a cycle time of 6 seconds / time. As shown in Table 2, the formability was good, the heat resistance was high, and the specific elastic modulus was high. In addition, the internal loss was appropriate and a good speaker diaphragm was obtained.

Example 2 100 parts of PET resin was prepared by melting and kneading 30 parts of mica having an average particle diameter of 40 μm and 3 parts of maleic anhydride graft-modified LLDPE (Mitsubishi Yuka Co., Ltd. Modic M-200F) with a twin screw extruder. Pellets and polyester elastomer (Toray
Extruder 3 for each of DuPont's Hytrel 6377) and Polyarylate (Unitika U-6000)
Extruded from a multilayer die using a table, and the PET resin composition (250
μ) / polyarylate (20μ) / elastomer (30μ)
The three-layer sheet was manufactured and the speaker diaphragm was formed in the same manner as in Example 1. As shown in Table 2, the formability was good, the heat resistance was high, and the specific elastic modulus and internal loss were appropriate. Thus, a good speaker diaphragm was obtained.

Comparative Examples 1 to 4 Speaker diaphragms were formed from single-layer sheets as shown in Table 1 in the same manner as in the examples. Table 2 shows the physical properties of the speaker diaphragm.

[Effect of the Invention] The multilayer speaker diaphragm of the present invention is polypropylene,
Superior in heat resistance and dimensional stability compared to polymers such as polyethylene, nylon 6, polystyrene, etc.By combining multiple layers, it has excellent specific modulus and internal loss that cannot be obtained with conventional single-layer sheets. In addition, it is possible to adopt a mass-production method of producing sheets by a co-extrusion molding method. Also, by vacuum pressure forming
The molding can be performed in a short cycle time, and the economic effect is great.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-281598 (JP, A) JP-A-56-6596 (JP, A) JP-A-54-151022 (JP, A) 105526 (JP, A) JP-A-58-188999 (JP, A) JP-A-59-61295 (JP, A)

Claims (1)

(57) [Claims] (1) To 100 parts by weight of polyethylene terephthalate, (a) 5 to 50 parts by weight of an inorganic compound having an average particle diameter of 50 μ or less, and (b) 0.5 to 10 parts by weight of an inorganic compound or polyolefin having an average particle diameter of 10 μ or less. A multilayer speaker diaphragm comprising a sheet in which a layer of a polyester resin other than polyethylene terephthalate is disposed in an intermediate layer between a layer of a compounded resin composition and a layer of a thermoplastic polyester elastomer.