JPS60162400A - Production of heatproof voice coil - Google Patents

Abstract

PURPOSE:To make a coil with excellent heatproof characteristic, sufficiently resistant to a high input/output reproduction by bonding and heating hardening by heating while applying a polarity non-aqueous solvent to a self fusible insulation wire applying/baking an adhesive paint on the insulating material. CONSTITUTION:A heatproof adhesive paint is uniformly applied on a polyamide glass cloth of 0.07mm. thickness by a bar coder to obtain a 0.015mm. thickness film, which is dried in a thermostatic oven holding in temperature of 120 deg.C for 5min to obtain a voice coil paper pipe. Then polyamide insulating paint is applied/ baked on a copper wire of 0.13mm. in diameter to obtain a 0.145mm. diameter insulating conductor, on which a heatproof adhesive paint is applied/baked to be a 0.155mm. diameter self fusible enamel copper wire. Then this copper wire is wound on the voice coil paper pipe to obtain a heat proof voice coil.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a voice coil with excellent side heating properties.

In recent years, audio equipment such as stereos has become increasingly high-output.

As high performance is increasingly required, the voice coils used in these devices also need to have vibration resistance and excellent heat breakdown resistance. In other words, there is a demand for a voice coil in which the coil support paper tube and the wire wound on its surface are firmly integrated.
Conventionally existing products have not yet achieved sufficiently satisfactory mechanical and thermal properties.

Voice coils are usually made by tightly wrapping self-adhesive enameled wire on a paper tube supporting the coil while coating it with an alcohol-based solvent, and then heating and drying it to fuse and integrate the wires and the paper tube and wire ring. It can be obtained by .

In this case, mechanical and thermal destruction of the coil most often occurs first at the bonding interface between the paper tube and the wire ring, and then at the adhesive interface between the wires. The main reasons for this are: (1) The paper tube and the wire have different coefficients of thermal expansion, which causes distortion between them. (2) Vibration may cause misalignment between the paper tube and the wire ring. In the worst case scenario, the coil will fall off and lose its function as a voice coil.

The present invention has been made in consideration of the above-mentioned matters. Therefore, a thermosetting resin adhesive coating of a specific material and composition is applied in a semi-cured state on the surface of a coil supporting paper tube in advance, and then the above-mentioned Self-bonding insulated wires with adhesive paint coated and baked through an insulating film are tightly wound while applying a polar non-aqueous solvent that dissolves the resin, and then heat treated to fuse the paper tube and wire ring. The main idea is to integrate the parts, and thereby improve the heat-resistant adhesive strength as shown in Figure 9. The details will be explained below.

The voice coil support paper tube is made of fully aromatic polyamide-based synthetic paper (Nomex paper), which is heat resistant, shows little dimensional change during heat treatment, and does not deteriorate even when exposed to high temperatures for long periods of time, and polyimide-impregnated glass nonwoven fabric. , nonwoven fabrics made of wholly aromatic polyamide fibers and glass fibers, synthetic papers made of wholly aromatic polyamide fibers and various ceramic short fibers, and various metal foils can be used, and although not limited to, polyimide-impregnated glass nonwoven fabrics are particularly effectively used. . In the case of a voice coil in which a self-bonding insulated wire is tightly wound directly on the surface of a heat-resistant paper tube, various experimental results show that the adhesion between the paper tube and the coil was insufficient. A thermosetting resin adhesive paint made by dissolving an aromatic polyamide resin or a mixture of a fully aromatic polyamide resin and a bismaleimide/triazine resin in a polar non-aqueous solvent that can dissolve these resins is applied to the surface of the paper tube in a semi-cured state. to form a uniform adhesive film with solvent reactivation. As a specific example of the fully aromatic polyamide resin used in this process, a fully aromatic polyamide resin obtained by a dehydrochlorination reaction between isophthalic acid dichloride and m-phenylenediamine is effective.

Bismaleimide/triazine resin is a thermosetting heat-resistant type having a triazine ring obtained by reacting a triazine resin monomer obtained by reacting bisphenol A with chlorocyan or a triazine resin oligomer obtained by increasing the molecular weight of this monomer with bismaleimide. Examples of the resin include BT resin (trade name, Mitsubishi Gas Chemical Co., Ltd.). An example of a polar non-aqueous solvent that can dissolve these resins is dimethylformamide.

N-methylpyridone and the like can be used.

On the surface of the voice coil support paper tube, on which the thermosetting resin adhesive paint of the specific material and composition is applied in a semi-cured state, the self-bonding insulated wire is made by applying the adhesive paint on the insulated conductor and baking it. It is tightly rolled while applying a polar non-aqueous solvent. Due to the presence of the polar non-aqueous solvent, the adhesive film of the self-bonding insulated wire is activated and exhibits adhesive properties. The wound voice coil is then heated and dried to harden the adhesive paint and firmly fuse and integrate the wires and the paper tube and wire ring.

Examples of the present invention will be described below.

Synthesis Example Synthesis of fully aromatic polyamide resin (poly m-7 enylene iso-7 talamide) A 200mg flask was equipped with a stirrer, a thermometer, and a dropping funnel, and 32.4i (0,5
mol), sodium hydroxide A 24. Of (0,6
mol) in 750 d of water. While thoroughly stirring the aqueous solution of
(o, 51 smol) of cyclohexanone 500-
dropwise within 5 minutes and stir vigorously for 10 minutes. After 1 hour of continued stirring, the polymer suspension was poured into a large amount of acetone, and the polymer was filtered off using a glass filter. The polymer is washed repeatedly with acetic hot water and dried. The obtained poly-m-7 enylene isophthalic, amide resin is 7°? The intrinsic viscosity in 96-thiosulfuric acid is 0.8-1.0 P.
/dl. This resin 70f was mixed with N-methyl-2
-Pyrrolidone 630? to prepare a solution with a concentration of 10%.

Using the fully aromatic polyamide resin obtained in the production synthesis example of a heat-resistant voice coil, or using a mixture of this and a bismaleimide-triazine resin,
A heat-resistant adhesive paint having the composition shown in Table 1 was prepared by dissolving it in N-methyl-2-pyrrolidone, which is a polar non-aqueous solvent. The bismaleimide-triazine resin is commercially available BT
-2112 (trade name of Mitsubishi Gas Chemical Co., Ltd.) was used.

Table 1: Apply the above heat-resistant adhesive paint evenly on a polyimide glass cloth with a thickness of 0.07 m to a coating thickness of 0.015 m, and dry for 5 minutes in a thermostatic oven at 120 °C. There are three types of voice coil paper tubes A, B (1) and B (2).
) was manufactured.

Next, polyamide-imide insulating paint was applied to a copper wire with a conductor diameter of 0.13 m so that the finished outer diameter was 0.145 BI, and then the above heat-resistant adhesive paint was applied on top of the insulated conductor, which was baked so that the finished outer diameter was 0.145 BI.
．． Three types of self-bonding enamelled copper wires a, b(1) and b(2) were manufactured by coating and baking to give a thickness of 155wII. The self-bonding enamelled copper wire is then wound around the voice coil paper tube in the combinations shown in Table 2 to produce a heat-resistant voice coil according to the present invention. The voice coil paper tube has a width of 2
It was cut into a rectangular shape with 5 words and a length of 76 m, and was mounted in a cylindrical shape on a winding jig with the side coated with adhesive paint facing outward. A self-bonding enamelled copper wire was wound on the surface thereof in two layers with 106 turns aligned while applying dimethylformamide. After the winding was completed, the winding jig was preheated in a drying oven at 120°C for 15 minutes, and then cured by heating in a drying oven at 230°C for 15 minutes to obtain a heat-resistant voice coil.

Table 2: In order to evaluate the heat resistance and structural characteristics of the obtained voice coil, 200 W of power was applied to the voice coil for 60 seconds (coil temperature rise approximately 500 to 350°C), and the surface condition of the wire after deterioration was determined. The state in which the wire rings peeled off from the paper tube and fell off, and the adhesive strength between the wires were measured. 5 Measurements of adhesive strength were performed as follows. The manufactured voice coil with a diameter of 25'Im was fitted into a cylindrical measuring jig with bearings embedded on both sides, one end of the winding was fixed to one end of the strain meter, and the measuring jig was further moved 50cb down. The adhesive force between wires is the first of the windings.
The adhesive strength between the first layer and the paper tube was measured using a tensile tester.The adhesive strength between the wire ring and the paper tube was measured using a tensile tester.

The test results are shown in Table-5. Note that the adhesive force value indicates the average of the measured values.

Table 3: Comparative examples include alcohol-soluble polyamide resin mixed with bismaleimide and epoxy resin as curing components for adhesive paint applied to paper tubes and adhesive paint for self-adhesive enamelled copper wire. This is a characteristic of a voice coil using a paint mainly composed of cresol and dissolved in a solvent.

As is clear from the test results, the voice coil obtained by the method of the present invention has significantly superior heat resistance characteristics compared to conventional products, and when incorporated into a speaker, it can withstand high input and high output playback. We can provide highly reliable products.

Applicant Tokyo Special Electric Wire Co., Ltd. Representative Tsugio Kogure

Claims (1)

[Claims] A wholly aromatic polyamide resin or a mixture of a wholly aromatic polyamide resin and a bismaleimide/triazine resin is dissolved in a polar nonaqueous solvent that can dissolve these resins, and a thermosetting resin adhesive coating is applied to the coil supporting paper tube in advance. The surface is coated in a semi-cured state, and on top of that, the self-bonding insulated wire, which has been coated and baked on an insulated conductor with the above adhesive paint, is tightly wound while applying the above polar non-aqueous solvent, and then heated and cured. A method for manufacturing a heat-resistant voice coil characterized by: