JPH03209999A - Manufacture of diaphragm for loudspeaker - Google Patents

Abstract

PURPOSE:To manufacture a diaphragm having a satisfactory frequency characteristic by using a high polymer paint obtained by dispersing a thermal expandable microcapsule consisting of a vinylidene chloride copolymer, etc., in a solvent in which a paste material of a polyester urethane resin, etc., is melted, for cone paper for the diaphragm of a loudspeaker. CONSTITUTION:For instance, vinylidene chloride foaming particles having the particle diameter of 10-20mum are added by 20weight%, in this case, to a water polyester compound urethane resin solution, stirred enough and applied to the part of a thermal expandable capsule forming part 1b on cone paper 1a for a diaphragm, and heated and dried. In such a way, in the thermal expandable microcapsule forming part 1b, a foaming body having 0.25g/cm<3> specific gravity is obtained. In this case, when specific gravity of a solid portion in the urethane resin solution is set to 1.18g/cm<3>, the foaming body having capacity of five folds is obtained. Also, with regard to the junction to the cone paper 1a for a diaphragm, as well, extremely high adhesive strength is obtained. In such a way, the diaphragm for a loudspeaker whose frequency characteristic is satisfactory is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION 2. The present invention relates to a method of manufacturing a speaker diaphragm mainly used for speakers incorporated in audio equipment.

Conventional technology In the past, the common method for improving the frequency characteristics of speakers was to attach a material with high mechanical loss, such as a rubber foam sheet, to the surface of a paper cone for a diaphragm using adhesive. Ta.

Problems to be Solved by the Invention However, in the conventional method of manufacturing a speaker diaphragm, a rubber foam sheet is cut into the required shape and dimensions as shown in FIG. The speaker diaphragm was completed by applying adhesive to the sheet, pasting the foam sheet onto the cone paper for the diaphragm, and drying it under pressure. Since the foam sheet 4 is cut into ring-shaped members 4a, a loss portion 4b is generated in the material.Also, after the cone paper for the diaphragm is pasted together, the ring-shaped rubber foam sheet 1 is cut before the adhesive dries. -4 A had to be dried while applying pressure with a jig or the like to prevent it from peeling off, which caused the problem that it was expensive, including the loss of material 4 b.

The present invention is intended to solve these problems, and aims to provide a method for manufacturing a speaker diaphragm that is inexpensive and has excellent acoustic characteristics.

Means for Solving the Problems In order to solve the above problems, the present invention provides thermally expandable microcapsules made of vinylidene chloride copolymer shell walls dissolved in an aqueous solvent with a glue made of polyester urethane resin or the like. Alternatively, create a polymer paint by dispersing it in an organic solvent, apply this polymer paint to the cone paper for a diaphragm, and heat and dry it to form a foam on a part of the upper surface of the cone paper for the diaphragm. This method is used to obtain a speaker diaphragm.

Effect: Therefore, according to the present invention, it is possible to manufacture a speaker diaphragm with excellent split resonance control characteristics through a relatively simple process, and since material loss is low, the speaker diaphragm can be provided at a low cost.

Embodiment FIGS. 1a and 1b show the structure of a speaker diaphragm obtained according to an embodiment of the present invention, in which 1a is a cone paper for the diaphragm, and 1b is a thermally expandable microcapsule forming part.

Next, the manufacturing method will be explained. Foamed vinylidene chloride particles having a particle size of 10 to 2 μm were added at 20% by weight to an aqueous polyester urethane resin solution (containing 45% solids) and stirred thoroughly to form a cone paper for diaphragm as shown in the figure. By coating the heat-expandable capsule-forming part 1b on the heat-expandable microcapsule-forming part 1a and heating and drying it, a foam having a specific gravity of 0.2 is g /cd in the heat-expandable microcapsule-forming part 1b is obtained. Since the specific gravity of the solid content in the urethane resin solution is 1.1 ag/cd, this means that a foam having six times the volume was obtained. Furthermore, extremely high adhesive strength was obtained when bonding to the diaphragm cone paper 1a. FIG. 2 shows the frequency characteristics of a 16-cone speaker equipped with a speaker diaphragm manufactured according to this embodiment.

In the 5-dimensional diagram, 2a is the thickness o when foamed to 5 times its volume.
, frequency characteristics of a speaker diaphragm using a 6 mm conventional polyester urethane foam bonded to a diaphragm cone paper using a rubber adhesive; This is the frequency characteristic of a loudspeaker diaphragm having a thermally expandable microcapsule formation portion with a thickness of 0.5 mtN. As is clear from the figure, according to the present invention, despite being an inexpensive manufacturing method, it is possible to obtain excellent frequency characteristics comparable to those of speakers manufactured using conventional methods.

FIG. 3 shows a comparison of the manufacturing method of the present invention.
A foam and a resin solution are mixed, this is applied to a cone paper for a diaphragm, and this is heated and foamed to obtain a diaphragm for a speaker. It can be seen that there is no loss and the manufacturing process can be reduced by one step.

In addition, in my opinion, the above aqueous polyester urethane resin solution contains benzene, toluene, xylene, isopropanol, butanol, ethylene glycol-61, n-hexane, cyclohexane, and turpentine.

1 of organic solvents such as perchlorethylene and styrene
The same effect can be obtained by using a resin solution in which a polyester-based urethane resin is dissolved as a glue in a seed or a mixed solution of two or more types.

Effects of the Invention As is clear from the above examples, the present invention disperses thermally expandable microcapsules made of vinylidene chloride copolymer etc. in an aqueous or organic solvent in which a sizing agent such as polyester urethane resin is dissolved. A speaker diaphragm with excellent frequency characteristics can be obtained by applying the prepared polymer paint to a cone paper for a speaker diaphragm and heating and drying it.

[Brief explanation of drawings]

FIGS. 1a and 1b are a plan view and a sectional view of a speaker diaphragm manufactured by a manufacturing method according to an embodiment of the present invention, and FIG. 2 is a speaker equipped with the same speaker diaphragm and a conventional speaker. Figure 3 is a process diagram showing the manufacturing method of the present invention, Figure 4 is a process diagram showing the manufacturing method, and Figure 5 is a process diagram showing the manufacturing method of the present invention. It is a top view showing the process of cutting out a ring shape from a rubber foam sheet. 1a... Cone paper for diaphragm, 1b...
Thermally expandable microcapsule forming part.

Claims (1)

[Claims] (1) Create a polymer paint by dispersing thermally expandable microcapsules made of a vinylidene chloride copolymer shell wall in an aqueous or organic solvent in which a glue material such as a polyester-based urethane resin is dissolved; A method for producing a diaphragm for a speaker, in which a foam is formed on a part of the upper surface of the cone paper for a diaphragm by applying this polymer paint to a cone paper for a diaphragm and drying it by heating. (2) The speaker according to claim 1, wherein the organic solvent is one or more of solvents such as benzene, toluene, xylene, isopropanol, butanol, ethylene glycol, n-hexane, cyclohexane, turpentine, perchlorethylene, and styrene. Manufacturing method of diaphragm for use.