JPH09294298A - Forming method for speaker material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the simple forming method for a speaker material in which adhesives or the like is not required, the manufacture process is reduced, mass-production is attained and the manufacture cost is reduced. SOLUTION: In a metallic die 1, a viscous rubber admixture (X) is located to an outer circumferential part of a speaker diaphragm 2, the die is fastened in this state and the viscous rubber admixture (X) is cured and foamed and compressed in the metallic die 1 to integrally form an edge 3 made of a viscoelastic rubber foamed body (Y) being a cured forming body of the viscous rubber admixture (X) at the outer circumferential part of the speaker diaphragm 2. The viscous rubber admixture (X) includes following components (A)-(D); (A) is a rubber, (B) is a softner, (C) is an organic foaming agent, (D) is a curing agent. Furthermore, (Y) is a viscoelastic foaming body whose tensile strength is set in a range of 0.1-100kg/cm<2> and whose specific gravity is set in a range of 0.07-1.2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for molding a speaker member in which an edge is integrally formed on the outer peripheral edge of a speaker diaphragm.

[0002]

2. Description of the Related Art In order to improve acoustic characteristics, an edge formed on an outer peripheral edge of a speaker diaphragm is used to suppress vibration of the speaker diaphragm and to prevent abnormal vibration such as resonance of the edge itself. In addition, various characteristics have been demanded that have an internal loss necessary to sufficiently dampen the extra vibration of the speaker diaphragm. Conventionally, in order to meet the above demands, for example, various edges made of the following materials have been developed. That is, a fiber type in which a thermosetting resin is impregnated into a woven or nonwoven fabric of natural fibers or synthetic fibers, formed by hot pressing, and applied with a dumping agent (attenuating agent). Urethane foam foamed foam is impregnated with bituminous material, urethane compression type molded and finished by hot pressing, rubber type molded and finished with a prescribed molding die using a rubber compound containing a vulcanizing agent, etc. can give.

[0003]

However, when forming the above-mentioned edge on the outer peripheral edge of the speaker diaphragm,
It has the following drawbacks. That is, the speaker diaphragm and the edge are separately molded, a primer (undercoating agent) or an adhesive is applied to each molded product, these are bonded through the adhesive, and finally the adhesive is dried. A process is needed. Therefore, the number of manufacturing processes increases and the work becomes complicated, and it takes time to manufacture, which makes mass production difficult.
There is a problem that the manufacturing cost rises.

The present invention has been made in view of the above circumstances and does not require an adhesive or the like, and the manufacturing process is shortened.
An object of the present invention is to provide a simple method for molding a speaker member, which can be mass-produced and can reduce the manufacturing cost.

[0005]

In order to achieve the above object, a method for molding a speaker member according to the present invention is such that a viscous rubber admixture (X) shown below is formed on the outer peripheral edge of a speaker diaphragm in a mold. Position, and after clamping the mold in that state, the viscous rubber mixture (X) is vulcanized and foamed and compressed by the mold, so that the viscous rubber mixture is added to the outer peripheral edge portion of the speaker diaphragm. The edge made of the following viscoelastic foam (Y) which is a vulcanized foam of (X) is integrally formed. (X) A viscous rubber mixture containing the following components (A) to (D). (A) Rubber. (B) a softener. (C) an organic foaming agent. (D) a vulcanizing agent. (Y) A viscoelastic foam having a tensile strength of 0.1 to 100 kg / cm ² and a specific gravity of 0.07 to 1.2.

That is, according to the method for molding a speaker member of the present invention, the viscous rubber mixture (X) is positioned on the outer peripheral edge of the speaker diaphragm in the mold, and the mold is clamped in that state, and then It is carried out by vulcanizing and foaming the viscous rubber mixture (X) and compressing it with the mold. Therefore, the viscous rubber mixture (X) melted by heat is compressed by the mold and flows on the speaker diaphragm, and the viscous rubber mixture (( The edge made of the viscoelastic foam (Y) which is the vulcanized foam of (X) can be integrally formed. Therefore, there is no need for conventional adhesives,
Since the manufacturing process is shortened and mass production is possible, the manufacturing cost can be significantly reduced.

As the viscoelastic foam (Y) used in the present invention, a viscous rubber mixture (X) containing the components (A) to (D) is used, which has a specific tensile strength and a specific strength. It is obtained by vulcanizing and foaming with a specific gravity. For this reason,
The foamed matrix forming the edge is formed by an integrated structure of the rubber component (A component) and the softening agent component (B component), and the foamed matrix has high strength,
Moreover, it is also a flexible elastic body. Furthermore, there is little change in physical properties due to the influence of environmental conditions such as the outside air temperature. Since the viscoelastic foam (Y) made of the viscous rubber mixture (X) is a rubber type, it is a foam and therefore has a small specific gravity and is lightweight. From these facts, excellent acoustic characteristics can be exhibited by using the viscoelastic foam (Y).

[0008]

Next, an embodiment of the present invention will be described in detail.

The viscous rubber mixture (X) used in the method for molding a speaker member of the present invention comprises rubber (component A),
A softening agent (component B), an organic foaming agent (component C), and a vulcanizing agent (component D), which are obtained by vulcanizing and foaming this special viscous rubber admixture (X). By
A viscoelastic foam (Y) is obtained.

The rubber (component A) is styrene-
Representative examples are synthetic rubbers such as butadiene rubber (SBR), nitrile-butadiene rubber (NBR), and ethylene-propylene-terpolymer rubber (EPT). Further, in addition to the above synthetic rubber, isoprene rubber (IR), chloroprene rubber (CR), isobutylene-
Examples thereof include synthetic rubbers such as isoprene rubber (IIR), ethylene-propylene rubber (EPR), and silicone rubber. These may be used alone or in combination of two or more. It is particularly preferable to use SBR from the viewpoint of moldability. Further, when two or more kinds are used together, NBR and EPT are used in combination from the viewpoint of durability such as weather resistance.

The softening agent (B
Component) includes plasticizers having a molecular weight of 300 to 500, such as dioctyl phthalate and dibutyl phthalate, and high molecular weight plasticizers having a molecular weight of 1,000 to 8,000, such as polyester plasticizers, and lubricating oils such as spindle oil, machine oil, and cylinder oil. Oils, process oils such as paraffin-based process oils and naphthene-based process oils, petroleum softeners such as paraffins such as liquid paraffin and vaseline, coal tar softeners such as coal tar and coal tar pitch, castor oil, Examples include aliphatic softeners such as cottonseed oil, waxes such as beeswax and lanolin, liquid or solid resins at ordinary temperature, and liquid rubbers such as polybutene. These are used singly or in combination of two or more in view of compatibility with each rubber. It is particularly preferable to use, for example, a naphthene-based process oil when SBR rubber is used. Further, when NBR rubber and EPT rubber are used in combination, paraffinic process oil and dioctyl phthalate (DOP) are used from the viewpoint of compatibility. The mixing ratio of the softener (component B) is preferably set in the range of 3 to 110 parts, more preferably 5 parts by weight, per 100 parts by weight of rubber (component A) (hereinafter abbreviated as "part"). ~ 80 parts, particularly preferably 20
~ 60 parts. That is, if the blending ratio of the softening agent is less than 3 parts, the flexibility is poor, and conversely, if it exceeds 110 parts, bleeding tends to occur on the surface.

As the organic foaming agent (component C) used together with the above components A and B, N, N'-dinitrosopentamethylenetetramine, N, N'-dimethyl-
Examples thereof include nitroso compounds such as N, N'-dinitrosoterephthalamide, azo compounds such as azodicarbosamide, azobisisobutylnitrile, and diazoaminobenzene, and sulfonyl hydrazide compounds such as benzenesulfonyl hydrazide and toluenesulfonyl hydrazide. Also,
Other known foaming agents such as p-toluenesulfonyl azide, 4,4'-diphenylsulfonyl azide, and 4,4'-oxybisbenzososulfonyl hydrazide are also included. These may be used alone or in combination of two or more. It is particularly preferable to use, for example, azodicarbosoamide, from the viewpoint of heating increase and gas generation amount due to temperature. Further, when two or more kinds are used in combination, for example, azodicarbosamide and 4,4'-oxybisbenzososulfonyl hydrazide are used in combination from the viewpoint of adjusting the foaming decomposition temperature. Then, the organic foaming agent (C
The compounding ratio of (component) is preferably set in the range of 0.1 to 35 parts, more preferably 1 to 30 parts, and particularly preferably 5 to 20 parts, relative to 100 parts of rubber (component A). That is, if the compounding ratio of the organic foaming agent is less than 0.1 part, the foaming becomes insufficient, and conversely, if it exceeds 35 parts, outgassing tends to occur.

As the vulcanizing agent (D component) used together with the above components A to C, sulfur, sulfur compounds such as sulfur chloride and sulfur dichloride, oximes such as p-quinonedioxime, hexadiamine carbamate and ethylenediamine carbamate. And other carbamates, selenium, litharge, etc. These may be used alone or in combination of two or more. It is particularly preferable to use, for example, sulfur from the viewpoint of rapid vulcanization by molding. Further, when two or more kinds are used in combination, a combination of sulfur and p-quinonedioxime is used. The mixing ratio of the vulcanizing agent (D component) is preferably set in the range of 0.01 to 10 parts, more preferably 1 to 3 parts, per 100 parts of rubber (A component). That is, if the compounding ratio of the vulcanizing agent is less than 0.01 part, the vulcanization becomes insufficient, and conversely, if it exceeds 10 parts, the rubber elasticity tends to be strong.

The viscous rubber admixture (X) used in the present invention contains, in addition to the components A to D, other additives as required, such as fillers, rubber reinforcing agents and vulcanization accelerators. A vulcanization accelerating aid, a UV absorber, an antiaging agent, a foaming aid and the like can be appropriately added.

Examples of the filler include inorganic fillers such as calcium carbonate, talc, clay, asbestos, pumice powder, glass fiber, mica, silica and hollow beads.
Organic fillers such as recycled rubber, shellac, wood flour, cork powder and the like can also be used. These may be used alone or in combination of two or more. In particular, for these fillers, those having uniform viscosity and good dispersibility are preferable in order to carry out molding and foaming evenly. From the viewpoint of reducing the weight of the speaker member, it is preferable to use talc or silica, for example.

Examples of the rubber reinforcing agent include carbon black such as channel black and furnace black, and silicas. These may be used alone or in combination of two or more.

Examples of the vulcanization accelerator include guanidine compounds such as diphenylguanidine and triphenylguanidine, thiazole compounds such as 2-mercaptobenzothiazole and dibenzothiazole disulfide, thiourea compounds such as thiocarbanilide and diethylthiourea, and tetramethyl. Examples thereof include thiuram compounds such as thiuram monosulfide and tetramethylthiuram disulfide, and dithiocarbamate compounds such as zinc dimethyldithiocarbamate and sodium dimethyldithiocarbamate. These may be used alone or in combination of two or more.

Examples of the vulcanization accelerator aid include metal oxides such as zinc white and magnesium oxide, fatty acids such as stearic acid and oleic acid and their derivatives, cyclohexylamines and dicyclohexylamines. These may be used alone or in combination of two or more.

Examples of the ultraviolet absorber include benzophenone compounds and benzotriazole compounds.

Examples of the antioxidants include phenol compounds, amine ketone compounds, and aromatic amine compounds.

Examples of the foaming aid include salicylic acid and urea.

The blending ratio of the above-mentioned other additives is such that the filler is 10 to 200 relative to 100 parts of the rubber (component A).
Parts, rubber reinforcing agent is 10 to 100 parts, vulcanization accelerator is 0.1
-20 parts, vulcanization accelerator 0.1-10 parts, ultraviolet absorber 0.1-10 parts, antioxidant 0.1-10 parts, foaming aid 0.1-30 parts It is preferable to set each.

The above viscous rubber mixture (X) used in the present invention is produced, for example, as follows. That is, it is produced by appropriately blending and kneading the above A to D components and other additives as necessary. The viscous rubber mixture (X) thus produced has a Mooney viscosity [ML _{(1 + 4)} 100 ° C.] set in the range of 1 to 30. It is preferable for producing the body (Y), and the Mooney viscosity is particularly preferably 2 to 15.

In the blending of the viscous rubber mixture (X), the preferred blending combination is SBR type rubber as the component A, naphthene type process oil as the component B, and C component as the component C from the viewpoint of molding vulcanization foaming in a short time. A combination of azodicarbososide and sulfur as the D component. Further, in addition to the above essential components A to D, other additives such as zinc white and stearic acid, talc as a filler, carbon black as a reinforcing agent, tetramethylthiuram disulfide as a vulcanization accelerator, and foaming. It is particularly preferable to use urea as an agent, 2,4-bis [(octylthio) methyl] -o-cresol as an antiaging agent, and a hydroxyphenylbenzotriazole derivative as an ultraviolet absorber. With such a combination of combinations, it is possible to obtain a molded vulcanized foam having a Mooney viscosity of 2 to 15 that is excellent.

Next, the method for molding the speaker member of the present invention will be specifically described with reference to the drawings. That is, first, the viscous rubber mixture (X) is formed into a sheet (thickness 1 to 10 mm) or film (thickness 0.1 to 0.1 mm).
1 mm). Then, as shown in FIG. 1, in a molding die 1 having a predetermined shape prepared in advance, a speaker diaphragm 2 such as cone paper and the above-mentioned viscous rubber mixture so as to be located at an outer peripheral edge portion of the speaker diaphragm 2. The object (X) is loaded and the mold is clamped. Then, the viscous rubber mixture (X) is
It is vulcanized and foamed by setting appropriate heating and pressurizing conditions, and is compressed in the direction of the arrow by the mold 1. Therefore, the viscous rubber admixture (X) that has been melted by heat
However, since it is compressed by the mold 1 and flows on the speaker diaphragm 2, as shown in FIG. 2, the rubber component of the viscous rubber admixture (X) is softened on the outer peripheral portion of the speaker diaphragm 2. Viscoelastic foam (Y) having a structure in which agent components are integrated
The edge 3 can be integrally formed. Alternatively, the viscous rubber admixture (X) may be punched into a sheet shape or a film shape, and then placed in a molding die 1 having a predetermined shape and vulcanized and foamed by the same method as described above, or The viscous rubber admixture (X) may be put into the molding die 1 having a predetermined shape as it is, and vulcanized and foamed by the same method as described above.

The viscous rubber mixture (X) is positioned in advance on the outer peripheral edge of the speaker diaphragm, and in this state, it is loaded into the mold and clamped, and vulcanized in the same manner as above. It may be foamed.

The above heating and pressurizing conditions are appropriately set depending on the type and blending ratio of each component constituting the viscous rubber mixture (X), and for example, the temperature is 80 to 250 ° C., the pressure is 1 to 10 kg / cm. it is preferable to set ² in such a heat capacity of 0.02 to 30 minutes. Particularly preferably,
At a temperature of 150 to 200 ° C. and a pressure of 4 to 6 kg / cm ² ,
The heat capacity is set to 5 to 10 minutes.

In the heat-foaming of the viscous rubber mixture (X), it is preferable that the foaming ratio after foaming is 1.05 to 30 times in view of the capacity of the molding die. , More preferably 1.1 to 15 times, and particularly preferably 1.5 to 7 times. It is preferable from the standpoint of the characteristics (acoustic characteristics, etc.) of the speaker member that the molding die is filled with the viscous rubber mixture (X) and heated to achieve such an expansion ratio.

Further, in the obtained viscoelastic foam (Y), the composition of the viscous rubber admixture (X), which is the forming material, and the foaming vulcanization conditions by heating and pressing are appropriately set,
The material loss coefficient is preferably set to 0.001 or more, and particularly preferably 0.01 or more. By setting the material loss coefficient in such a range, the acoustic characteristics are remarkably improved, and a speaker member that transmits the vibration of the speaker with high sensitivity can be obtained.

The material loss coefficient is defined as follows. Material loss coefficient (tan δ) = (E ₂ ) / (E ₁ ) E ₁ : storage elastic modulus E ₂ : loss elastic modulus

The viscoelastic foam (Y) thus obtained is
The tensile strength should be set to 0.1-100 kg / cm ² . Particularly preferably 5 to 20 kg / cm
² That is, if the tensile strength is less than 0.1 kg / cm ² , the strength may be insufficient and tear may occur.
If it exceeds 100 kg / cm ² , the strength is too strong and vibration does not occur. Further, the viscoelastic foam (Y) used in the present invention must have a specific gravity in the range of 0.07 to 1.2. Particularly preferably, it is 0.3 to 0.8. That is, when the specific gravity is less than 0.07, the high sound pressure causes breakage, and when the specific gravity exceeds 1.2, the speaker member becomes too heavy and the edge does not vibrate smoothly with respect to the sound pressure.

Next, examples will be described together with comparative examples.

[0033]

Examples 1 to 9, Comparative Examples 1 and 2 Tables 1 and 2 below
The viscous rubber admixture was prepared by blending the components shown in Table 1 in the proportions shown in the same table. Then, this viscous rubber mixture was molded into a sheet having a thickness of 2 mm. Then, the sheet-shaped viscous rubber mixture and the speaker diaphragm were put into the above-mentioned molding die and clamped. Next, the viscous rubber mixture is foamed and vulcanized under a heating condition of 200 ° C. for 1 minute and compressed by the mold, and the viscoelasticity of the viscous rubber mixture is applied to the outer peripheral edge of the speaker diaphragm. An edge made of body foam was integrally formed. As the speaker diaphragm, cone paper (tan δ = 0.04) having a specific gravity of 0.65 was used.

[0034]

[Table 1]

[0035]

[Table 2]

The physical properties [tensile strength, specific gravity, foaming ratio, and material loss coefficient] of the edges of the thus-obtained example products and comparative product were measured according to the following methods. The results are shown in Tables 3 and 4 below.

[Tensile Strength] The tensile strength was measured according to the JIS K 6301 rubber tensile strength test method.

[Specific gravity] The specific gravity was measured according to JIS K6767.

[Expansion Ratio] It was calculated by the back calculation method from the specific gravity.

[Material Loss Coefficient] It was measured by a method using a dynamic viscoelasticity measuring device (frequency 1 Hz). The measurement was performed by incorporating the integrally molded product of the speaker diaphragm (cone paper) and the edge obtained above into a speaker.

[0041]

[Table 3]

[0042]

[Table 4]

Then, the integrally molded product of the speaker diaphragm (cone paper) and the edge (specific gravity 0.4) obtained in the above (Example 1 product) was incorporated into a speaker, and a loss coefficient ta was obtained.
The acoustic characteristics at nδ = 0.50 were measured. In addition, the acoustic characteristics in the case of using the product of Comparative Example 1 instead of the product of Example 1 were measured. The results are also shown in FIG. In the figure,
A curve X shows the acoustic characteristics of the speaker using the example 1 product, and a curve Y shows the acoustic characteristics of the speaker using the comparative example 1 product. The measurement of the above-mentioned acoustic characteristics for each frequency was performed based on a sound pressure response. As a result, there is less distortion in the high frequency range due to the weight reduction due to foaming and the characteristics of rubber elasticity,
Good acoustic characteristics were obtained even in the low frequency range. As a result of performing the measurement in the same manner in the other examples, almost the same, that is, good acoustic characteristics were obtained. On the other hand, it is clear from FIG. 3 that the product of Comparative Example 1 is a rubber solid that does not foam, has a large specific gravity, and has a larger strain than the product of the Example. The other comparative products have small expansion ratios and show characteristics close to solid.

As described above, the products of the respective examples, which are the edges having a small specific gravity obtained by vulcanizing and foaming with the rubber component as the base, are lightened and are superior in acoustic characteristics to the conventional edges. I understand. Furthermore, the products of the examples are hardly affected by the outside air temperature, and the sound quality and the like do not deteriorate. Then, as a result of subjecting each example product to an accelerated weather resistance test (500 hours) with a sunshine weather meter and a deterioration test of the edge material by immersion in warm water (168 hours), there was almost no change, and the weather resistance and water resistance were almost unchanged. It turns out to be excellent.

[0045]

As described above, according to the method of molding the speaker member of the present invention, the viscous rubber mixture (X) is positioned on the outer peripheral edge portion of the speaker diaphragm in the mold, and the mold is maintained in that state. After tightening, the viscous rubber admixture (X) is vulcanized and foamed and compressed by the mold. Therefore, the viscous rubber mixture (X) melted by heat is compressed by the mold and flows on the speaker diaphragm, and the viscous rubber mixture (( The edge made of the viscoelastic foam (Y) which is the vulcanized foam of (X) can be integrally formed. Therefore, according to the present invention, a conventional adhesive or the like is not required, the manufacturing process is shortened, and mass production is possible, so that the manufacturing cost can be significantly reduced.

As the viscoelastic foam (Y) used in the present invention, the viscous rubber mixture (X) containing the above components (A) to (D) is used, which has a specific tensile strength and a specific tensile strength. It is obtained by vulcanizing and foaming with a specific gravity. For this reason,
The foamed matrix forming the edge is formed by an integrated structure of the rubber component (A component) and the softening agent component (B component), and the foamed matrix has high strength,
Moreover, it is also a flexible elastic body. Furthermore, there is little change in physical properties due to the influence of environmental conditions such as the outside air temperature. Since the viscoelastic foam (Y) made of the viscous rubber mixture (X) is a rubber type, it is a foam and therefore has a small specific gravity and is lightweight. From these facts, excellent acoustic characteristics can be exhibited by using the viscoelastic foam (Y).

[Brief description of drawings]

FIG. 1 is an explanatory view showing an example of a method for molding a speaker member of the present invention.

FIG. 2 is an explanatory view showing an example of a method for molding the speaker member of the present invention.

FIG. 3 is a curve diagram showing acoustic characteristics of a speaker produced by incorporating an integrally molded product (a product of Example 1 and a product of Comparative Example 1) of a speaker diaphragm (cone paper) and an edge.

[Explanation of symbols]

 1 mold 2 speaker diaphragm 3 edge made of viscoelastic foam (Y)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location B29L 31:38

Claims (1)

[Claims] 1. A viscous rubber admixture (X) described below is positioned in an outer peripheral portion of a speaker diaphragm in a mold, and the mold is clamped in that state, and then the viscous rubber admixture (X) is vulcanized. By foaming and compressing with the mold, an edge made of the following viscoelastic foam (Y), which is a vulcanized foam of the viscous rubber mixture (X), is formed on the outer peripheral edge of the speaker diaphragm. A method for molding a speaker member, characterized by being integrally formed. (X) A viscous rubber mixture containing the following components (A) to (D). (A) Rubber. (B) a softener. (C) an organic foaming agent. (D) a vulcanizing agent. (Y) A viscoelastic foam having a tensile strength of 0.1 to 100 kg / cm ² and a specific gravity of 0.07 to 1.2.