JPH0392099A - Diaphragm for speaker - Google Patents

Abstract

PURPOSE:To obtain a diaphragm for speaker with excellent moisture proof, high specific modulus and high external appearance quality by coating an implegnated agent formed with mica powder subject to titanium oxide processing mixed into a acrylic resin onto a diaphragm main body, drying and heating the agent. CONSTITUTION:To a diaphragm main body 1 paper-made of a pulp such as NUKP and formed, an implegnating agent 2 is implegnated, which is formed by adding natural mica whose surface is coated with titanium oxide with coating rate of 15-40% and whose granular size is 30-200mu into an acrylic resin whose viscosity is nearly 90cps whose solids content is nearly 8% in the weight ratio of 20%. Then the implegnating agent 2 is formed to the entire face of the diaphragm main body 1 by heating at nearly 50 deg.C for 10 minutes. Thus, since the implegnating agent 2 of the acrylic resin is applied to the entire face of the diaphragm main body 1, the specific modulus and the tensile strength at wet and swollen state are improved. Moreover, since the mica has a higher elastic modulus than that of pulp, the specific modulus is improved by putting mica powder into the diaphragm main body to improve the specific modulus and the frequency characteristic with a flat characteristic extended to a high frequency is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a diaphragm for sub-spaces used in various types of audio equipment.

Conventional technology Conventional speaker diaphragms include pulp cones made from pulp material (1) (2) and molded using a hot press, and resin cones molded from resin materials such as polypropylene. Aluminum,
There were metal cones made from metals such as titanium.

Problems to be Solved by the Invention Bulb cones are widely used because they are cheap and lightweight, but they have problems such as low rigidity and sensitivity to humidity. Although resin cones are excellent in productivity and quality variation, they have problems such as poor adhesion, low specific elastic modulus E/ρ, and inability to freely change sound quality. Metal cones were expensive and heavy, and like resin cones, the sound quality could not be changed freely.

The present invention aims to eliminate the above-mentioned conventional drawbacks and provide a speaker diaphragm that has excellent moisture resistance, a high specific modulus of elasticity, and a high quality appearance.

Means for Solving the Problems In order to solve the above problems, the present description describes an impregnating agent in which titanium oxide or titanium oxide and mica powder treated with iron oxide is mixed into a NCO cross-linked acrylic resin material. A speaker diaphragm is constructed by coating the plate body and heating and drying it.

Function: With the above structure, the acrylic resin impregnating agent is applied to the entire diaphragm body, so that the specific elastic modulus and the tensile strength when wet are significantly improved. In addition, since mica powder has a higher elastic modulus than bulp, the specific modulus of elasticity can be improved by putting mica powder into the diaphragm body. Furthermore, the mica powder has been surface-treated, and by layering it inside the pulp diaphragm body, a product with the luster of real stock and the luster of metal can be obtained.

EXAMPLE Hereinafter, a speaker diaphragm according to an example of the present invention will be described with reference to the drawings.

FIG. 1 shows a cone-shaped diaphragm main body made by paper-making pulp fibers, and the diaphragm main body 1 is formed by paper-making pulp such as NUKP. The diaphragm body 1 is coated with titanium oxide with a coverage of 15 to 40%, and natural mica in the form of mica powder with a particle size of 30 to 200 μ is placed in an acrylic resin with a viscosity of about 90 cps and a solid content of about 8%. The diaphragm body 1 was impregnated with an impregnating agent 2 added at a ratio of 20%, and dried by heating at about 50° C. for 10 minutes to form an impregnating agent layer 2 on the entire surface of the diaphragm body 1.

The physical properties of this loudspeaker diaphragm are as follows: The product of the present invention has a higher specific modulus of elasticity and higher tensile strength than the conventional bulb cone. Furthermore, there is little deterioration in strength even when wet. FIG. 2 shows the sound pressure frequency characteristics of a speaker using this speaker diaphragm and a speaker using a conventional pulp diaphragm. Since the product of the present invention has high rigidity, it has a flat frequency characteristic that extends to higher frequencies.

In addition, in the above example, mica powder whose surface was treated with titanium oxide with a coverage of 15 to 40% was shown.
A coating rate of 2 is added to titanium oxide as a treatment agent for mica powder.
Similar effects can be obtained using ~20% iron oxide.

Effects of the Invention Since the speaker diaphragm of the present invention is constructed as described above, it has a high specific modulus of elasticity and excellent moisture resistance, and can also have pearl luster or metallic luster, resulting in a high appearance quality. It is a product of high industrial value that can be manufactured using

[Brief explanation of drawings]

FIG. 1 is a half-sectional view of a speaker diaphragm of the present invention, and FIG. 2 is a sound pressure frequency characteristic diagram of a conventional speaker diaphragm and a speaker using the speaker diaphragm of the present invention. 1... diaphragm body, 2... impregnating agent.

Claims (2)

[Claims] (1) An impregnating agent in which mica powder with a particle size of 30 to 200μ, whose surface has been treated with titanium oxide with a coverage rate of 15 to 40%, is mixed into a -NCO crosslinked acrylic resin agent is used to form a cone by making pulp material into paper. A speaker diaphragm that is impregnated into a diaphragm body that is molded into a diaphragm body. (2) The speaker diaphragm according to claim 1, wherein iron oxide with a coverage of 2 to 20% is further used in addition to the titanium oxide as a treatment agent for mica powder.