JPS60210098A - Manufacture of heat resistant voice coil - Google Patents

Abstract

PURPOSE:To improve heat resistant adhesiveness by forming a heat resistant electric insulation coating layer on a surface of a coil support paper tube and by heating an auto-adhesionable insulation electric wire after a specific adhesive coating is applied and said wire is closely wound. CONSTITUTION:An electric insulation coating material such as polyimide having a heat resistant grade superior to H-type is uniformly coated and baked on a surface of a heat resistant support paper tube. On the coating material, a thermosetting resin adhesive coating material obtained by dissolving a mixture of an aromatic polyamide resin in a polar nonaqueous solvent is applied in the semi- hardened state, and a homogeneous adhesive coating with the solvent reactivity is formed, on which the auto-adhesionable insulation electric wire coated and baked on insulation conductor with an adhesive paint is closely wound, while a polar nonaqueous solvent is applied. By heating and drying the wound voice coil, the adhesive paint is hardened, a space between a line, the paper tube and a line ring are securely fused and unified.

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.

High performance is increasingly required, and the voice coils used for this need to have vibration resistance and excellent thermal 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 still have mechanical and thermal weaknesses and have not been able to provide sufficiently satisfactory characteristics.

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. You can especially get it.

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) Misalignment occurs between the paper tube and the wire ring due to vibration. 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, and consists of forming a heat-resistant electrical insulating film layer on the surface of the coil supporting paper tube in advance, and applying a thermosetting resin adhesive coating of a specific material and composition on the top layer in a semi-cured state. On top of that, a self-bonding insulated wire with the adhesive paint applied and baked through the insulation film is tightly wound while applying a polar non-aqueous solvent that dissolves the resin, and then heat treated. The main idea is to fuse and integrate the paper tube and the wire ring, thereby improving the heat-resistant adhesive strength.

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 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 wire ring is not sufficient. Electrical insulating paint made of polyimide, polyamideimide, polyesterimide, etc. with a heat resistance grade of class H or above is uniformly applied and baked on the surface of the paper tube in advance, and the upper layer is made of wholly aromatic polyamide resin, polyamideimide resin, or wholly aromatic polyamide resin. Alternatively, a thermosetting resin adhesive paint made by dissolving a mixture of polyamide-imide resin and bismaleimide/triazine resin in a polar non-aqueous solvent that can dissolve these resins is applied in a semi-cured state to create a uniform adhesive with solvent reactivation. Allow a film to form. As a specific example of the fully aromatic polyamide resin used here, a fully aromatic polyamide resin obtained by a dehydrochloric acid reaction between isophthalic acid dichloride and m-phenylenediamine is effective.

Further, specific examples of polyamide-imide resins include polyamide-imide resins obtained by a dehydration condensation reaction of trimellitic acid anhydride and diaminodiphenyl ether,
AI polymer (trade name of Amoco, USA) or HI4
oo (trade name of Hitachi Chemical Co., Ltd.) is optimal.

Bismaleimide triazine resin is bisphenol A
Triazine 81 is a triazine resin obtained by reacting chlorocyan with chlorocyan, or triazine 81, which is obtained by increasing the molecular weight of triazine 81. A thermosetting heat-resistant resin having a triazine ring obtained by further reacting a fatty oligomer with bismaleimide, such as BT resin ( Mitsubishi Gas Chemical Co., Ltd. (product name). Dimethylformamide, N-methylpyrrolidone, and the like can be used as polar nonaqueous solvents that can dissolve these resins.

In this way, a heat-resistant electrical insulating film layer is formed on the surface of the coil supporting paper tube, and a thermosetting resin adhesive coating of a specific material and composition is applied to the upper layer in a semi-cured state. A self-bonding insulated wire obtained by coating and baking the above-mentioned polar non-aqueous solvent onto an insulated conductor is tightly wound while applying the 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-phenylene isophthalamide) A 2000 m flask was equipped with a stirrer, a thermometer, and a dropping funnel, and 52.4 f (0,
3 mol), sodium hydroxide z4. oi (0.6m
ol) is dissolved in water 750a. While thoroughly stirring this aqueous solution, isophthalic acid chloride 63.97 (
Cyclohexanone 600d containing 0,315 mol) was added dropwise within 5 minutes and stirred 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. Wash the polymer repeatedly with acetone and hot water and dry. The resulting poly-m-7 enylene isophthalamide resin has a weight of 70p and an intrinsic viscosity of 0.8-1.96% in sulfuric acid. o li
'/dl. This resin 70? , N-methyl-
It was dissolved in 2-pyrrolidone 6501 to prepare a solution with a concentration of 10%.

Manufacture of heat-resistant voice coil 1. Glass fiber cloth with a thickness of 0.070111 mm and surface treated with synthetic resin (dimensions: 300 m + 1 x 30! it)
Using a percoder, a commercially available polyimide resin paint, Toshi Nice (trade name, Toshisha Co., Ltd.) was applied to a film thickness of 0.01511 mm.
111, and heated to 15 in a thermostatic oven at 120°C.
After pre-drying for a minute, it was cured by heating in a constant temperature bath at 230°C for 15 minutes to form a strong insulating film. Next, the fully aromatic polyamide resin adhesive paint obtained in the synthesis example was applied and baked in a semi-cured state on the upper layer to form an adhesive film with a coating thickness of 0.010 mm, thereby producing a voice coil paper tube.

On the other hand, polyamide-imide insulating paint was coated and baked on a copper wire with a diameter of 0.15111 so that the finished outer diameter was 0.145tiB, and then the fully aromatic polyamide resin obtained in the synthesis example and the commercially available N-
Adhesive paint dissolved in methyl-2-pyrrolidone has a maximum finished outer diameter of 0.15! The mixture was coated and baked to obtain a heat-resistant self-bonding insulated wire.

The voice coil paper tube has a width of 25t111. After cutting it into a rectangular shape with a length of 76 cranes, it was mounted in a cylindrical shape on a winding jig with the adhesive coating surface facing outward, and the heat-resistant self-bonding insulated wire was heated twice while applying dimethylformamide to its surface. The layer had 106 turns of aligned winding. And the winding jig! M1
Pre-dry in a constant temperature bath at 20°C for 15 minutes, then dry at 23°C.
The voice coil according to the present invention was manufactured by heating and curing in a constant temperature bath at 0°C for 15 minutes.

2 Nomex with a thickness of 0.0701 m as a thin leaf base material (
Example 1 except that the voice coil paper tube was made of a non-woven fabric (non-woven fabric) and polyamide-imide resin was used as the adhesive coating. A voice coil according to the present invention was manufactured under the same conditions as described above.

3. Thickness 0.0701 as a thin leaf base material! A commercially available polyamide-imide resin paint, AI-polymer (trade name of Amo coo, USA), was used as a heat-resistant insulating material for the lower layer, and fully aromatic polyamide resin and bismaleimide were used as adhesive paints. A voice coil according to the present invention was manufactured under the same conditions as in Example t, except that the voice coil paper tube was made of a mixture with triazine resin.

4. Voice coil paper tube using AI-Polymer (trade name of Amoco, USA), a commercially available polyamide-imide resin paint, as the base heat-resistant insulating paint, and a mixture of polyamide-imide resin and bismaleimide-triazine resin as the adhesive paint. Other than that, the same as in Example 1. A voice coil according to the present invention was manufactured under the same conditions as described above.

In order to evaluate the heat-resistant adhesive strength of the voice coils of Examples 1 to 4, a power of 200 W was applied to the voice coils for 60 seconds (
The adhesive force between the paper tube and the wire ring was measured before and after heat deterioration (coil rise temperature of about 350 to 400°C). Adhesive force was measured as follows. 1. Insert the fabricated 25-diameter voice coil into a cylindrical measuring jig with bearings embedded on both sides, fix one end of the winding to one end of the strain meter, and set the measuring jig at a speed of 30 crri/M. The adhesive strength between the first layer of the winding wire and the paper tube was measured using a tensile tester.

The test results are shown in the table below. Note that the numerical values indicate the average of the measured values.

Heat-resistant adhesive strength of voice coil The comparative examples shown are alcohol-soluble polyamide resin with bismaleimide resin and epoxy resin as curing components for adhesive paint applied to paper tubes and adhesive paint for self-bonding enamelled copper wire. These are the characteristics of a voice coil using a paint made by dissolving a mixture of the following: in a solvent mainly composed of cresol. Reference examples are Examples 1 to 4.
These are the characteristics of voice coils without an underlying layer of heat-resistant insulating paint, that is, those with adhesive paint applied directly to the surface of the paper tube.

As is clear from the test results, the voice coil obtained using the method of the present invention has significantly superior heat resistance characteristics compared to conventional products, and when incorporated into a speaker, it can also be used for high input and high output reproduction. We can provide products that are durable and reliable.

゛・Nino′

Claims (1)

[Claims] A heat-resistant electrical insulation film layer is formed in advance on the surface of the coil supporting paper tube, and the upper layer is a wholly aromatic polyamide resin, a polyamideimide resin, or a mixture of a wholly aromatic polyamide resin or a polyamideimide resin and a bismaleimide/triazine resin. A thermosetting resin adhesive paint dissolved in a polar non-aqueous solvent capable of dissolving these resins is applied in a semi-cured state, and then an adhesive paint mainly composed of the above thermosetting resin is applied onto the insulated conductor. A method for manufacturing a heat-resistant voice coil, which comprises tightly winding a self-bonding insulated wire coated and baked on the surface of the wire while applying the polar non-aqueous solvent, and then heating and hardening the wire.