JPS6150498A - Center cap for speaker - Google Patents

Abstract

PURPOSE:To obtain a cap having light and sufficient fire-resistant for a center cap by impregnating solution of salt of a water soluble or alcohol soluble cyanamide derivative into a made paper material, after drying, heating, pressuring and molding to a prescribed shape. CONSTITUTION:The center cap 15 for a speaker is manufactured. First, the material in which NBKP is beaten and adjusted to a beating degree 20 deg.SR is prepared. After that, it is dispersed, becomes suspension and paper is made by a prescribed shaped paper making net. At this time, as raw material, after paper making, the materials are made dry. After that, a paper material which is obtained by phospholic acid di-guanidine solution (alcohol solution is also preferable.) with prescribed density is impregnated, an adhering quantity of phosphoric acid di-guanidine solution is adhered to paper materials up to 3%-15%, preferably, 7%-8%. Again, drying is executed. After that, the material is molded into a prescribed shape.

Description

[Detailed description of the invention] Technical field The present invention relates to a center cap for a speaker.

Generally speaking, the center cap for a speaker needs to be lightweight, have high rigidity, and have a moderate amount of internal loss, just like the diaphragm.In particular, paper center caps are easy to work with. It is widely used in speakers.

FIG. 1 is a cross-sectional view of a cone-shaped speaker. Magnet 1 is attached to upper plate 2 and lower plate 3
The center ball 4 is placed on the lower plate 3, and a magnetic circuit is constituted by these. A voice coil bobbin 11 having a voice coil 6 wound thereon is coupled to the diaphragm 5 at the opening end of the concave portion, and a filler 4-
t/tub 15 is placed.

The opening edge of the diaphragm 5 is supported together with a gasket 10 via an edge 9 at the tip of a frame 8 fixed to the upper plate 2, and the opening edge of the recess of the diaphragm 5 is supported by a damper fixed to the frame 8. 7 and voice coil 6 bobbin 1
1.

Various attempts have been made to make the diaphragm of a speaker flame retardant because the voice coil of the speaker generates heat due to excessive input, and the diaphragm is used in a location exposed to high temperatures, such as a television cabinet. Conventionally, however, center cap materials have been made of paper coated and impregnated with resin or paper mixed with flame-retardant fibers, and in either case, the center cap itself has the disadvantage of being heavy.

Furthermore, since paper, which is a flammable material, is used, it is difficult to make the speaker flame-retardant and reduce the weight of the vibrating part at the same time. Therefore, it can be said that flame retardant measures for the center cab were insufficient for the speaker as a whole.

Conventional flame retardants for speaker center caps include:
1111L There are boron compounds, halogen compounds, phosphoric acid compounds, etc. Boric acid and boron-based compounds are highly hygroscopic and significantly deteriorate the moisture resistance of products. Halogen-based compounds themselves are weak in imparting flame retardancy to paper and cannot be effective unless attached in large quantities; therefore, the use of these flame retardants makes the center cap heavy. Phosphoric acid compounds have a flame retardant effect on paper, but their decomposition temperature is low, and for example, center cap molding usually takes 2
It will be difficult to maintain the shape unless it is carried out at temperatures above 00°C, but this molding temperature and the decomposition temperature of the phosphoric acid flame retardant are almost the same. area, making its use difficult. Another problem with halogen flame retardants is that they generate toxic gas when ignited.

To 11 11 An object of the present invention is to provide a center cap for a speaker that is lightweight and has sufficient flame retardancy.

The center cap for a speaker of the present invention is characterized by impregnating paper stock with a solution of a salt of a water-soluble or alcohol-soluble cyanamide derivative, drying it, and then heating and pressurizing it to form it into a predetermined shape.

The present invention will be explained below based on tables.

In the present invention, cyanamide, which is a compound with a high decomposition temperature, is used, and other derivatives such as atomic groups having IL elements are used to achieve a synergistic effect of flame retardation and reduce adhesion. In (a), good flame retardancy is imparted to the speaker center cap.

Cyanamide is represented by NC-NH2'r-ara, and its derivatives include, for example, guanidine of the following formula.

HNC(NH2)2 When used in the form of a salt of HNC(NH2)2 and phosphoric acid, for example, a salt of 1-guanidine phosphate, 2-guanidine phosphate, or 1-sulfuric acid, the decomposition temperature is high and the reaction between phosphorus and nitrogen or sulfur is high. Due to the synergistic effect, good flame retardancy can be obtained with a small amount of adhesion. Furthermore, cyanamide has low hygroscopicity and exhibits a flame retardant effect even with a small amount of adhesion, so the speaker center cap according to the present invention has excellent moisture resistance.

In addition, the salt of guanidine sulfamate is JISK-01
According to the acute toxicity of Japanese medaka based on the factory wastewater test method of 02, the survival rate after 24 hours at 7000 ppm was 10.
0%, and in a similar test for the salt of guanidine phosphate, the survival rate after 24 hours was 25001) l) m and 100%.
%Met. These flame retardants have no problem with their acute toxicity, and since the flame retardant effect is due to the dehydration effect of phosphoric acid or sulfamic acid, no harmful gas is generated when ignited.

Application example 1 Manufactures center caps for speakers.

First, NBKP is beaten and adjusted to a beating degree of 20 degrees SR. Thereafter, it is dispersed in a papermaking tank to form a suspension, and paper is made using a papermaking net of a desired shape. At this time, 71% of raw materials were used in the proportions shown in Table 1. After making the paper, it is dried. Thereafter, the obtained paper stock is soaked in an aqueous diguanidine phosphate solution (alcoholic solution may be used) at a predetermined temperature to reduce the adhesion amount of diguanidine phosphate to 3% to 15%, preferably 7%.
~8% is deposited on the paper stock. Let dry again. Thereafter, it is molded into a predetermined shape.

Table 1 N'BKP' 20 degrees SR 100% Urea-based cleaning agent 3% direct dye
4% fixative
1.5% Application Example 2 Paper stock is made and dried using the same raw material composition as in Application Example 1. Thereafter, the methylol melanin resin is applied to the paper stock by impregnation. Thereafter, it is molded into a predetermined shape. At this time, the diguanidine phosphate and the methylol melanin resin can be made into the same aqueous solution or alcohol solution.

The flame retardancy of the cyanamide derivative in the present invention is determined by the amount of the cyanamide derivative attached to the paper, and is not greatly affected by the concentration of the aqueous impregnating solution. That is, the amount of adhesion can be adjusted by impregnating paper and squeezing it with a roll or the like.

The flame retardance of the speaker center caps obtained in Application Examples 1 and 2 was equivalent to UL94V-0.

The formula of the cyanamide derivative used in the above application example is as follows.

1-guanidine phosphate HNC(NH2)2 H3POa 2-guanidine phosphate (HNC(NH2))2 H3PO4 guanidine sulfamate HNC(NH2)H8○3NH2 The flame retardant treatment in the present invention is not limited to paper but can also be applied to other natural fibers. It can also be applied to woven and non-woven fabrics made of chemical fibers.

In particular, the flame retardant treatment according to the present invention is also effective for paper stocks made by mixing non-flammable or flame-retardant fibers such as metal fibers, carbon fibers, glass fibers, synthetic fibers, etc. One thing has been confirmed.

For example, it can be applied to diaphragms such as wood valves.

However, in the case of a diaphragm made of paper, pulp, etc., water-soluble fI
(7)e! 11 e m &);S L, °'”0
601°65 ““ There is 1. Therefore, in this case, add 711! sizing agent in advance! ! 1 is required. Further, it is also possible to impregnate and apply a flame retardant and then heat and pressurize it using a mold or the like.

The molding of Leno filter paper according to the present invention can be used not only for the center cap of a speaker, but also, for example, for a diaphragm using paper.

Effect: The speaker center cap of the present invention thus obtained is made of paper or the like, so it is rigid and has a moderate internal loss, making it suitable as a center cap. . It also has excellent flame retardancy equivalent to UL94v-0.

Furthermore, since cyanamide derivatives absorb little moisture, the resulting flame-retardant hint V-tube does not deform due to moisture absorption and can maintain the shape of the center cap in a stable state. A stable, lightweight center cap that does not affect frequency characteristics can be obtained.

As mentioned above, since it has excellent flame retardancy, the risk of ignition is greatly reduced compared to conventional speakers even if the speaker is placed in a highly humid area near the power source of a television/radio or the like.

Please note that guanidine phosphate and guanidine sulfamate are non-toxic and their use is harmless to the human body.
No special ventilation equipment is required for its manufacture.

[Brief explanation of the drawing]

The drawing is a partial cross-sectional view of a cone-shaped speaker. Explanation of symbols for main parts 1... Magnet 2... Upper plate 3... Lower plate 4... Center pole

Claims (3)

[Claims] (1) A center cap for a speaker, characterized in that a paper stock is impregnated with a solution of a salt of a water-soluble or alcohol-soluble cyanamide derivative, dried, and then heated and pressurized to form a predetermined shape. (2) The center cap for a speaker according to claim 1, wherein the solution of the water-soluble or alcohol-soluble cyanamide derivative salt contains a thermosetting resin. (3) For a speaker according to any one of claims 1 or 2, wherein the paper stock contains metal fibers, carbon fibers, glass fibers, or synthetic fibers. center cap.