JPH03107300A - Multilayer speaker diaphragm - Google Patents

Abstract

PURPOSE:To obtain a speaker diaphragm compatible with economical efficiency by constituting it of a sheet in which the layer of polyester resin excepting polyethylene terephthalate is arranged as an intermediate layer to the layer of thermoplastic polyester elastomer. CONSTITUTION:The diaphragm is constituted of the sheet made by arranging the layer of polyester excepting polyethylene terephthalate as the intermediate layer between the layer of resin composition matter in which 5 to 50 weight parts of inorganic compound smaller than average grain size 50mu end 0.5 to 10 weight parts of the inorganic compound or polyolefine smaller than average grain size 10mu are mixed to 100 weight parts of polyethylene terephthalate and the layer of thermoplastic polyester elastomer. Thus, the speaker diaphragm, which is good in formability, high in heat resistance, and appropriate and favorable in specific elastic modulus and internal loss, can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a speaker diaphragm represented by a speaker cone or the like.

[Conventional technology]

Conventionally, paper or polyolefin polymer films and materials mixed with inorganic materials have often been used as materials for speaker cones.
7-154994, JP-A-62-205127, JP-A-62-149296, JP-A-62-
Liquid crystal films are also beginning to be used, as seen in Japanese Patent No. 101281 and the like.

[Problem to be solved by the invention]

However, speaker cones using paper or polyolefin polymer film have the advantage of high internal loss tan δ and low price; ), the performance as a speaker cone is insufficiently balanced. For this reason, inorganic materials are used in paper and polyolefin.
In particular, methods have been used to increase the specific elastic modulus by mixing mica and carbon fiber, but there is a limit to the amount of inorganic materials that can be mixed, and the current situation is that a fully satisfactory specific elastic modulus has not been achieved. be. Additionally, polyolefin is disadvantageous in terms of heat resistance, making it unsuitable for car stereos and high-output speakers.

In addition, in the case of speaker diaphragms using liquid crystal polymers, although high specific elastic modulus, internal loss, and heat resistance can be obtained, liquid crystal polymers are expensive, have high anisotropy, and have a non-uniform structure. A fully satisfactory speaker cone cannot be obtained.

The present invention has been made to solve these problems, and aims to provide a speaker diaphragm that has high heat resistance, appropriate specific modulus, internal loss, and economical efficiency.

[Means to solve the problem]

That is, the present invention provides polyethylene terephthalate 10
A resin composition containing (a) 5 to 50 parts by weight of an inorganic compound with an average particle size of 50 μ or less, and (b) 0.5 to 10 parts by weight of an inorganic compound or polyolefin with an average particle size of 10 μ or less per 0 parts by weight. This is a multilayer speaker diaphragm made of a sheet in which a layer of a polyester resin other than polyethylene terephthalate is arranged as an intermediate layer between a layer of a polyester resin and a layer of a thermoplastic polyester elastomer.

The polyethylene terephthalate used in the present invention includes starting materials such as terephthalic acid or an alkyl ester derivative of terephthalic acid, and ethylene glycol, as well as isophthalic acid, naphthalene dicarboxylic acid,
diphenyl ether dicarboxylic acid, diphenyl metadicarboxylic acid, diphenyl sulfone 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, dicarboxylic acid components such as octadecane-1,18-dicarboxylic acid, 6-ethyl-hexadecane-1,16-dicarboxylic acid, propylene glycol, diethylene glycol, butylene glycol, pentyl glycol, neopentyl glycol, hexamethylene glycol, polyethylene It may contain a glycol component such as polyalkylene glycol such as glycol or polytetramethylene glycol, and 80 mol% or more of the repeating units constituting this are composed of ethylene terephthalate.

The inorganic compound used as component (a) of the present invention has different effects as a smoothing agent for the sheet surface, a reinforcing material, an anisotropic relaxant of mechanical properties, and a crystal nucleating agent depending on its particle size and shape. Generally, inorganic compounds with an average particle size of 50 microns or less are useful, since the effect diminishes when the average particle size exceeds about 50 microns.

Specific examples of inorganic compounds with an average particle size of 50μ or less include carbon black, silica, calcium carbonate, synthetic silicic acid and silicate, zinc white, hallosite clay, kaolin, basic magnesium carbonate, mica, talc, quartz powder, Examples include wollastonite, dolomite powder, titanium oxide, barium sulfate, calcium sulfate, alumina, etc.
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 diameter of 1Oμ or less used as component (0) of the present invention include talc, calcium carbonate, and wollastonite, but talc is particularly effective in the present invention.

As component (0), polyolefin is also very effective instead of the above, and it not only promotes crystallization but also
This has the advantage of improved impact resistance.

As polyolefin, low density polyethylene (LDP
E), polyethylenes such as high-density polyethylene (HDPH) and linear low-density polyethylene (LLDPE), polypropylene (PP), and modified polyolefins such as maleic anhydride graft modification thereof can be used.

It is also possible to use an inorganic compound with an average particle diameter of 10μ or less and a polyolefin in combination.

Regarding the blending ratio of each component in the resin composition of the present invention, component (a), that is, an inorganic compound with an average particle size of 50 μm or less, is less than 5 parts by weight per 100 parts by weight of the polyester component, and is used as a surface smoothing agent for the sheet. However, it is insufficiently effective as an anisotropic relaxant and reinforcing agent for mechanical properties, and conversely, if it is added in an amount exceeding 50 parts by weight, mechanical properties are significantly deteriorated.

Therefore, the blending amount of component (a) is 1 polyester component.
The amount is 5 to 50 parts by weight, preferably 10 to 30 parts by weight.

In addition, component (0), that is, thermoplastic polyester 100
If the amount of inorganic compound or polyolefin with an average particle size of 10μ or less is less than 0.5 parts by weight, the increase in crystallinity will be slow (and the economical problem of molding). On the other hand, even if the amount exceeds 10 parts by weight, the rate of increase in crystallinity is saturated and the mechanical properties begin to deteriorate. The amount of the inorganic compound or polyolefin with a size of 10 microns or less is 0.5 to 10 parts by weight, preferably 1 to 5 parts by weight.

In addition, the resin composition in the present invention may further contain a heat stabilizer, an oxidation stabilizer, a light stabilizer, a lubricant, a pigment, a flame retardant,
Additives such as plasticizers may be added.

The thermoplastic polyester elastomer used in the present invention includes a polyester-polyester type elastomer in which the hard segment is an aromatic polyester and the soft segment is an aliphatic polyether, and the hard segment is an aromatic polyester and the soft segment is an aliphatic polyester. Polyester-polyester type elastomers can be used.

The polyester resins used in the present invention include polybutylene terephthalate, 1,4-cyclohexane methylene terephthalate, polyarylates and polycarbonates whose main raw materials are bisphael A, and polyhydroxybenzoic acid, 2,6 naphthalene dicarboxylic acid, etc., whose main raw materials are polyester resins. It is possible to use fully aromatic and semi-aromatic liquid crystalline polyesters, etc., and copolymer resin compositions containing 40% or more thereof.

Further, the weight ratio of the polyethylene terephthalate resin to the thermoplastic polyester elastomer and the polyester resin in the present invention is 40 to 94:3 to 30:3 to
30, preferably 60-90:5-20:5-20. Furthermore, as a method for manufacturing the multilayer sheet in the present invention, a method of coextruding components using a multilayer die to form a film is more advantageous in terms of manufacturing cost, but it can also be manufactured by methods such as extrusion lamination.

〔Example〕

Next, the present invention will be specifically explained using examples. In the following examples, parts indicate parts by weight.

Example 1 Polyethylene terephthalate resin 10 with an intrinsic viscosity of 1.0
0 parts, 30 parts of mica with an average particle size of 40μ, and LLDPE
(Mitsubishi Yuka LX529) Pellets made by melt-kneading 3 parts using a twin-screw presser and polyester thermoplastic elastomer (Toshi/DuPont Hytrel 4047)
and liquid crystal polyester (Unitika Rodran LC-
5000) was extruded from a multilayer die using three dedicated extruders, respectively, to obtain PIET resin composition (125μ)/liquid crystal polyester (10μ)/elastomer (30μ)/liquid crystal polyester (10μ)/PET resin composition (125μ).
A 300μ thick sheet of 5 layers was produced. The obtained sheet is passed through a vacuum/pressure (plug assist) molding machine (
Asano Laboratory ■, FLPD-1414-H-20, 14
When the sheet was preheated to 0°C and a speaker diaphragm was formed at a metal temperature of 170°C and a cycle time of 6 seconds/time,
As shown in Table 2, a speaker diaphragm with good moldability, high heat resistance, appropriate specific modulus of elasticity, and appropriate internal loss was obtained.

Example 2 Pellets were prepared by melting and kneading 100 parts of PIiT resin, 30 parts of mica with an average particle size of 40 μm, and 3 parts of maleic anhydride graft modified LLDPIE (Mitsubishi Yuka Modified 200F) using a twin-screw presser; Polyester elastomer (Toshi DuPont Hytrel 6377) and polyarylate (Unitika U-6000) were extruded through a multilayer die using three dedicated extruders, and PE
T resin composition (250μ) / polyarylate (20μ)
A sheet with a three-layer structure of /elastomer (30μ) was manufactured and a speaker diaphragm was molded in the same manner as in Example 1. As shown in Table 2, it had good moldability, high heat resistance, and a specific modulus of elasticity. A good speaker diaphragm with appropriate internal loss was obtained.

Comparative Examples 1 to 4 Speaker diaphragms were made 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 has superior heat resistance and dimensional stability compared to polymers such as polypropylene, polyethylene, nylon 6, and polystyrene. It has excellent specific elastic modulus and internal loss, and it has become possible to mass-produce sheets by coextrusion molding. In addition, vacuum-pressure molding and the like enable molding in a short cycle time, which has great economic effects.

Claims (1)

[Claims] For 100 parts by weight of polyethylene terephthalate, (
b) 5 to 50 parts by weight of an inorganic compound with an average particle size of 50 μm or less,
(b) A layer of polyester resin other than polyethylene terephthalate in the intermediate layer between a layer of a resin composition containing 0.5 to 10 parts by weight of an inorganic compound or polyolefin with an average particle size of 10 μ or less and a layer of thermoplastic polyester elastomer. A multilayer speaker diaphragm characterized in that it is composed of sheets arranged with.