JPS62150995A - Diaphragm for speaker - Google Patents

Abstract

PURPOSE:To obtain a diaphragm having high rigidity and suitable degree of internal loss which is highly fire-resistant, humidity-resistance, and weather- resistance by adding to the diaphragm made of wood pulp a halogen-contg. condensed phosphate soluble to an organic solvent, a sulfo-acid derivative having amido radical, and a thermoplastic resin. CONSTITUTION:The wood pulp, as an essential component, is made paper to form a desired shape. And to the resulting diaphragm, a halogen-contg. condensed phosphate soluble to the organic solvent, the sulfo-acid phosphate derivative having amido radical, and a thermoplastic resin are added. As a result, the diaphragm for speaker that is excellent in humidity-resistance and fire- resistance can be obtained. The halogen-contg. condensed phosphate soluble to the organic solvent has far lower hygroscopic property in comparison with ordinary phosphate.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vibrating body such as a diaphragm or a center cap used in an electrodynamic speaker.

■JU MARUKI An electrodynamic speaker as shown in the sectional view of FIG. 6 has been known for some time. A magnetic circuit is constituted by an annular magnet 2 held between an annular yoke 1, and a cylindrical voice coil bobbin 3 around which a voice coil 3a is wound is disposed at the center of the magnetic circuit. The voice coil bobbin 3 is bonded to the center of the cone-shaped diaphragm 4. The voice coil bobbin 3 is held by a frame 7 via a damper 6.

The outer periphery of the vibrating body 4 is held by a frame 7 via an edge 5. A center cap 8 is fitted in the center of the vibrating body 4, and a packing 9 is attached to the outer periphery of the edge 5.

The diaphragm 4 and center cap 8 are known as speaker moving bodies, and are made of paper material.

These vibrating bodies mainly made of wood pulp have a small mass, a relatively high Young's modulus, and a moderate internal loss.
It has other advantages such as being able to easily make paper even with complicated shapes, but it has the disadvantage of being flammable and vulnerable to fire.

Therefore, the voice coil may generate heat due to excessive input, causing the voice coil bobbin and the vibrating body to catch fire. Also, the vibrating body may catch fire when used in a place where there is a risk of being exposed to high temperatures, such as a television cabinet. , the vibrating body must be flame retardant.

From this point of view, inorganic asbestos has traditionally been used as a material for vibrating bodies. However, since this has a large quality m, the efficiency of the speaker deteriorates, and it cannot be said to be a desirable imaging device in terms of sound quality.

What about flame retardant treatment agents for wood pulp? I acid, Ill element,
Examples include halogenated hydrocarbons and phosphoric acid compounds.

Boric acid and boron have this effect through heat absorption and melt coating, but
It has the drawback of being highly hygroscopic and significantly reducing the strength of the wood pulp substrate. Further, phosphoric acid compounds such as ammonium phosphate have a flame retardant effect due to dehydration and carbonization, but they also have the disadvantage of being hygroscopic and reducing the strength of the wood pulp substrate. In either case, the weight of the vibrating body increases in the atmosphere due to the moisture absorption f1, making the frequency characteristics of the speaker unstable.

On the other hand, examples of halogenated hydrocarbons include hexabromobenzene and decabromodiphenyl oxide.
Although they are not hygroscopic, they are difficult to dissolve in organic solvents, and the flame retardant effect of halogens is not effective against cellulose, so the flame retardant effect cannot be achieved unless a large amount is attached.

SUMMARY OF THE INVENTION An object of the present invention is to provide a flame-retardant moving body with excellent moisture resistance.

The vibrating body for a speaker of the present invention includes a base material made from wood pulp fibers as the main raw material, and a base material 11 attached to the base fibers.
a flame retardant interposed between t4, and the flame retardant is a mixture of an organic solvent-soluble halogen-containing condensed phosphoric acid ester, an organic solvent-soluble phosphonic acid derivative having an amide group, and an organic solvent-soluble thermoplastic resin. shall be.

Circle-1-1 The present invention involves forming a paper into a desired shape mainly from wood pulp, and adding halogen-containing condensed nisdel phosphate soluble in organic solvents and amide phosphate soluble in organic solvents to the resulting speaker vibrating body. By combining a phosphonic acid derivative having a group with a thermoplastic resin soluble in an organic solvent, a vibrating body for a speaker with good moisture resistance and flame retardance can be obtained.

The halogen-containing synthetic phosphate ester soluble in organic solvents is represented by the following structural formula.

In the formula, R1 represents an alkyl group or a phenyl group, X represents a halogen atom, and n represents an integer. The ester absorbs much less moisture than normal phosphoric acid. In other words, the hygroscopicity of phosphoric acid is the parent tree of oxygen atoms! 1. However, the alkyl group or phenyl group bonded to the ester is hydrophobic, so overall, due to these effects,
Halogen-containing condensed phosphoric acid ester absorbs less moisture than phosphoric acid.

Since the halogen-containing condensed phosphoric acid ester has an alkyl group or a phenyl group, its molecular weight is large. Therefore, in order to obtain a desired flame retardancy by using only a halogen-containing condensed phosphoric acid ester, it is necessary to increase the amount of the halogen-containing condensed phosphoric acid ester attached to the wood pulp substrate. The flame retardant rank is
It is usually determined by the amount of attached atoms that contribute to flame retardancy. Atoms that contribute to the flame retardancy of the halogen-containing integrated phosphoric acid ester are phosphorus P and halogens, such as Cj and Br.

Therefore, in the present invention, a phosphonic acid derivative having an amide group, which is also soluble in organic solvents, is used in combination with a halogen-containing condensed phosphoric acid ester to reduce the overall amount of flame retardant attached to the base fiber. It is.

Phosphonic acid derivatives soluble in organic solvents are represented by the following structural formula.

In the formula, R2, R3 and R4 represent an alkyl group or a phenyl group, and m and n represent integers. Although this derivative has excellent flammability due to the synergistic effect of phosphorus P and nitrogen N, it is more hygroscopic than ammonium phosphate because the amide group is hydrophilic. absorbs less moisture.

Halogen-containing condensed Nisder phosphate and amide 2. If the phosphonic acid derivative with t is
It is possible to obtain a product with less fil and good flame retardancy.

However, the phosphonic acid derivatives with an amide group,
Most halogen-containing condensed phosphoric acid esters are liquid at room temperature, whereas they can be obtained as solid at room temperature.
Its molecular weight is small and it cannot provide the so-called strength of resin. Therefore, simply adding these to a speaker vibrating body mainly made of wood pulp will not provide the rigidity required for the vibrating body.

The present invention is characterized in that a thermoplastic resin soluble in an organic solvent is simultaneously added to these components, thereby imparting the necessary rigidity to the vibrating body for a speaker.

Thermosetting resins are thought to be more advantageous in terms of heat resistance and flame retardancy than resins that are soluble in organic solvents; however, when using melamine-based or urea-based resins, This requires a step of adhering it and a step of curing it, which is disadvantageous in terms of cost. Furthermore, for example, when using a phenolic or epoxy resin, heat of 200° C. or higher is required to cure the resin. On the other hand, in the case of a halogen-containing condensed phosphoric acid ester or a phosphonic acid derivative having an amide group, the dehydration carbonization start temperature and thermal decomposition temperature are close to 200°C. Therefore, when a phenol-based or epoxy-based resin, a gen-condensed phosphoric acid ester, and a phosphonic acid derivative having an amide group are used, the vibrating body for a speaker is not physically stable.

Therefore, 1. In order to use a thermoplastic resin, it must satisfy the heat resistance and weather resistance required for, for example, a vibrating body for a speaker, and be compatible with the above-mentioned flame retardant. If they are not compatible with each other, each impregnation treatment step can be performed separately, but this is disadvantageous in terms of cost.

Thermoplastic resins soluble in organic solvents in the present invention include, for example, acrylic resins such as methyl methacrylate and esters thereof, acid 1'ltulose, and cellulose acetyl butylene 1 to Yuki no lerulose derivatives. , or a mixture thereof.

Figure 1 shows the halogen-containing synthetic phosphoric acid ester (curve A in the figure), the phosphonic acid derivative having an amide group (curve B in the figure), and the ammonium phosphate (curve C in the figure) according to the present invention. The adhesion l (wt%) when attached to the vibrating body base material and the water content (wt%) showing the effect
This is a graph showing the relationship between However, the test conditions are
45℃.

This is the moisture content immediately after being left at 95% RH for 48 hours.

According to FIG. 1, it can be seen that the water content in the case of only the halogen-containing condensed phosphoric acid ester used in the present invention (curve A) is lower than the water content of the base material (wood pulp), which is 11.5%.

Furthermore, it can be seen that in the case of only the phosphonic acid derivative having an amide group (curve B), the water content is higher than that of the base material, but it is smaller than that in the case of only ammonium phosphate (curve C>).

When classifying flame retardance into combustible items, self-extinguishing items that burn for a few seconds but quickly disappear, and items that do not ignite at all without raising a flame, the relationship with the amount of adhesion is 1
It will look like a table.

Table 1 The conversion ratio of the halogen-containing synthetic phosphorus 1li9 ester (A> and the phosphonic acid derivative (B) having an amide group) in the present invention is △:B-4 to 6:0.5□”1. A good ratio is good, preferably A:B-5:1.The relationship between Ij and moisture content when this mixture is attached to a substrate is as shown by the curve in Figure 1. The original value of the base material is almost maintained.Furthermore, the flame retardance is as shown in Table 2.

As the thermoplastic resin, for example, Medyl methacrylate 1~
When applying this to the vibrating body, the relationship between the amount of adhesion and the stiffness is as shown in the graph in Figure 2, and the relationship between the (=I deposit and internal loss) is as shown in the graph in Figure 3. It can be seen that there is a close relationship between the amount of adhesion, stiffness, and internal loss.

As can be seen from FIGS. 2 and 3, there is an appropriate range for the amount of resin deposited, and in the present invention, the amount of resin deposited is 3 to 7%.
is good, preferably about 5%. In the present invention, the mixing ratio of the halogen-containing condensed phosphate ester, the phosphonic acid derivative having an amide group, and the thermoplastic resin is as follows: halogen-containing condensed phosphate ester:Bosphone M having an amide group (
In4F body: thermoplastic resin -5:1:2 is good, and the amount of adhesion to the wall H is good to be 18% to 20%.

An embodiment of the present invention will be described based on FIG. 4.

First, in the beating step S1, NBKP (softwood bleached kraft pulp) is sufficiently swollen.
Beat it with The concentration at this time is about 3.0%, and the freeness is 15 degrees SR in terms of Schopper Rigler freeness. still,
Synthetic IE 11 and glass string may be mixed into the bulb.

Next, after beating, predetermined dyeing is performed as a dyeing step S2,
Get raw materials.

Next, as an adjustment step S3, various adjusting agents are added to this raw material 1 and diluted to about 0.05% to prepare a pulp suspension.

Next, as a papermaking process S4, the prepared pulp suspension is made into paper using a wire mesh having a predetermined shape.

Next, as a drying step S5, a predetermined 5°! 180 with a shaped mold
It is dried by heating and pressurizing at a temperature of .degree. C. to 200.degree. C. to obtain a predetermined vibrating body base material.

Next, as a flame retardant treatment liquid preparation step S6, solutions as shown in Table 3 are prepared.

Next, the base material is soaked in the treatment solution obtained in the impregnation step S7.
Soak for minutes to saturate.

Next, in a drying step S8, the base material is dried in hot air at 90° C. to 100° C., and in an outer and inner shape cutting step S9, the outer and inner circumferences are cut to obtain a vibrating body.

The vibrating body of this example obtained by the flame retardant treatment was M
I exposed it to a gas flame for 10 seconds and it was a bll. Even if I exposed it to a gas flame for 10 seconds again, it did not ignite. It was V in the rank of Ul-1 = 9/I.
-I am annoyed by the performance equivalent to O.

Next, Table 4 shows the physical properties of this example. Examples ■ and ■ shown here are the results of each vibrating body of this example obtained by the prefectural association in which the pressure during heating and pressurization was changed to 2 Kg/ci and 5 Kg/cM in the drying process Pi+, S5. Comparative Examples (2) and (2) are the physical properties of the base materials of the vibrating bodies of Examples (2) and (2) before the pyrolysis treatment. Comparing the results before and after the treatment, all examples have a higher rounding rate than Comparative Example J.

Table 4 and FIG. 5 show the frequency characteristics of the present example (2) and comparative example (2) after assembly into the speakers, respectively, as curves X and Y, respectively. It can be seen from the figure that the vibrating body subjected to the flame retardant treatment according to the present invention has almost the same performance as the vibrating body base material before the treatment.

In the present invention, high rigidity is achieved by adding an organic solvent-soluble halogen-containing condensed phosphoric acid ester, a phosphonic acid derivative having an amide group, and a thermal 11 plastic resin to a vibrating body made of wood pulp. In addition to providing a vibrating body for a speaker with moderate internal loss, it is possible to obtain a vibrating body for a speaker that is flame retardant and has excellent moisture resistance and weather resistance.

The present invention applies not only to a vibrating body for a speaker and a center 1ψ tube, but also to paper parts mainly made of cellulose, such as gaskets and voice coil bobbin paper.

It can also be applied to wrapping paper for voice coils, etc. It can also be applied to edges and dampers made of cotton cloth or the like.

Although impregnation treatment is the main feature of the present invention, spraying, brushing, etc. can also be performed, and the present invention is not limited to the impregnation method. If a method such as spraying is used, it can be applied to speaker boxes mainly made of wood, for example.

[Brief explanation of drawings]

Figure 1 is a graph showing the relationship between the adhesion amount and moisture content when the treatment liquid is applied to the substrate, and Figure 2 is the A7 rate of the substrate when the treatment liquid is applied to the base material. Figure 3 is a graph showing the relationship between the coating amount and the internal loss of the substrate when the treatment liquid is attached to the substrate.
The figure is a diagram explaining the manufacturing process for obtaining the vibrating body of the present invention, FIG. FIG. 2 is a cross-sectional view of an electrodynamic speaker. Explanation of symbols of main parts 1... Annular yoke 2... Annular magnet 3a... Voice coil 3... Cylindrical voice coil bobbin 4...
・Cone type photographing plate 5... Etch 6... Damper 7... Frame 8... Center cap 9... Packing = 18-

Claims (2)

[Claims] (1) Consists of a base material made from wood pulp fibers as the main raw material and a flame retardant attached to the base fibers and interposed between the base fibers, the flame retardant being an organic solvent-soluble halogen-containing condensed phosphoric acid A vibration damper for a speaker, characterized in that it is a mixture of an organic solvent-soluble phosphonic acid derivative having an ester or amide group and an organic solvent-soluble thermoplastic resin. (2) The vibrating body for a speaker according to claim 1, wherein the base material includes one or more types of fiber materials selected from synthetic fibers, glass fibers, and carbon fibers.