KR20130036433A - Speaker diaphragm - Google Patents

Abstract

PURPOSE: A speaker diaphragm and a manufacturing method thereof are provided to satisfy a high elasticity and a high internal loss rate. CONSTITUTION: A speaker diaphragm is a part of a web(30) formed from electro-spinning fibers, and includes a web internal layer(31) maintaining a fibrous shape and a heat transformation layer(32) thermally deformed and formed in one side of the web internal layer. The web internal layer has an internal loss rate higher than the web heat transformation layer, and the web heat transformation layer has an elastic rate higher than the web internal layer.

Description

Speaker diaphragm {SPEAKER DIAPHRAGM}

The present disclosure relates generally to a speaker diaphragm and a method for manufacturing the same, and more particularly, to a speaker diaphragm and a method for manufacturing the same using a web or microfiber web manufactured by an electrospinning process or the like. The electrospinning process here should be understood as a broad electrospinning process including a meltblow-spinning process, a force-spinning process, and a blowing system and a high electric field system added to these processes. do. Meltblowing is a process for producing fibers by blowing high-temperature, high-pressure air into a conventional melt spinning process in which the raw polymer is heat-melted and extruded from the spinning nozzle into air to cool to form fibers. The force-spinning process is a method of preparing fibers by dropping a polymer solution onto a spinning spinning nozzle (spin coating) and ejecting the polymer out using centrifugal force. The main components of this system are spinneret, collector, environmental control room, control system, motor and brake. Multiple spinnerets are continuously supplied with polymer in the cavity, and the solution or melt is ejected through the orifice by centrifugal force to become nanofibers. Both solutions and molten phase materials have the advantage of being usable.

Herein, the background art relating to the present disclosure is provided, and these are not necessarily meant to be known arts.

FIG. 1 is a view showing a speaker diaphragm disclosed in Japanese Patent Application Laid-Open No. S62-289098, wherein a voice coil bobbin 100 and a voice coil 200 are provided, and a speaker diaphragm 300 is provided at one end of the voice coil bobbin 100. ) Is provided. In the selection of the loudspeaker diaphragm 300 material, three factors that most influence the frequency characteristics of the loudspeaker are important. These three factors would be: (1) high modulus of elasticity, (2) large internal loss (high damping), and (3) small density. Although it is ideal to use a lightweight, high modulus and internal loss material for loudspeaker diaphragms, these requirements are in opposition. Since the elastic modulus and the internal loss rate have opposite properties, a high elastic modulus has a relatively low internal loss rate, thereby limiting low tone reproduction, and a high internal loss rate tends to reduce the elasticity rate and degrade sound reproduction. In view of this, the speaker diaphragm 300 has a three-layer structure in which a polyimide sheet having a large internal loss ratio is used as a core material and a polyamide sheet having a high elastic modulus is attached to both surfaces. On the other hand, there is also a method for producing a speaker diaphragm using a single body such as a carbon sheet (carbon sheet). However, the speaker diaphragm thus obtained is not suitable for mass production due to the low internal loss effect and insufficient sound quality of the speaker as well as the complicated manufacturing process.

This will be described later in the Specification for Implementation of the Invention.

SUMMARY OF THE INVENTION Herein, a general summary of the present disclosure is provided, which should not be construed as limiting the scope of the present disclosure. of its features).

According to one aspect of the present disclosure, there is provided an according to one aspect of the present disclosure, comprising: a speaker diaphragm comprising: a web inner layer that retains fibrous shape as part of a web formed from electro-spinning fibers; And a web inner layer formed on at least one side of the web inner layer, wherein the web inner layer has a higher heat loss rate than the web inner layer, and the web inner layer has a higher modulus of elasticity than the inner layer of the web. A speaker diaphragm is provided.

This will be described later in the Specification for Implementation of the Invention.

1 is a view showing a speaker diaphragm shown in Japanese Patent Laid-Open No. S62-289098,
2 is a view illustrating an example of a speaker diaphragm according to the present disclosure;
3 is a view showing an example of an electrospinning apparatus that can be used in the present disclosure,
4 is a view illustrating an example of a method of manufacturing a speaker diaphragm according to the present disclosure;
5 is a table showing physical properties before calendering in Examples 1 to 4;
6 is a table showing physical properties after the calendar work of Examples 1 to 4;
7 is a SEM photograph before thermocompression bonding of the fibrous web as in Example 1,
8 is a SEM photograph after thermocompression bonding of the fibrous web as in Example 1,
9 is a SEM photograph after thermocompression bonding of a fibrous web as in Example 3. FIG.

The present disclosure will now be described in detail with reference to the accompanying drawing (s).

2 is a view showing an example of a speaker diaphragm according to the present disclosure, wherein the speaker diaphragm 13 is a web formed from electrospinning fibers, and the web inner layer 31 retaining a fibrous shape. And a web heat-deformation layer 32 thermally deformed on the film or on both sides thereof. The porous film is made of electrospun fiber to increase the internal loss rate through the web inner layer 31, reduce the weight, and heat-deform the outer surface to form a web heat deformation layer 32 having high elastic modulus. The speaker diaphragm 13 can be easily manufactured without forming a multilayer.

3 is a view showing an example of an electrospinning apparatus that can be used in the present disclosure, the electrospinning apparatus 40 is a supply unit 110 and a supply unit 110 for supplying a polymer material for the fiber raw material in the molten state, Spinning unit 120 having a plurality of spinning nozzles 122 for discharging the polymer solution supplied from the form of charged filaments or fibers, and accumulating the filaments radiated from the spinning unit 120 to a predetermined thickness The collector 130 disposed to be spaced apart from the radiation nozzles 122 by a predetermined distance, the control unit 140 installed on at least both sides of the radiation unit 120, and the control unit 140 and the collector 130 to surround the filament stream. Air conditioner unit 160 for injecting air into the space between the induction unit 150 and the radiation unit 120 and the collector 130, and evaporating the solvent in the space to the outside. . The supply unit 110 is a storage container 112 for storing a solution in which a polymer material as a fiber raw material is dissolved, and a pump 114 for pressurizing and supplying the solution stored in the storage container 112 to the spinning unit 120. ) And a distributor 116 and a delivery tube 118 for dispensing the solution to the respective nozzles. The spinning unit 120 performs a function of spinning in the direction of the collector 130 in the form of fine filaments in a state in which the fiber raw material solution supplied from the supply unit 110 is charged. The spinning unit 120 includes at least one spinning nozzle pack 126 in which a plurality of spinning nozzles 122 are disposed. The number of spinning nozzles 122 constituting the spinning nozzle pack 126 or the number of spinning nozzle packs 126 constituting the spinning unit 120 takes into account the size, thickness, and production speed of the web to be manufactured. Is determined. When several polymer materials are to be spun, a separate spin nozzle pack may be provided. The collector 130 may be grounded to have a potential difference with respect to a voltage applied to the radiation unit 120, or may be applied with a negative voltage. The collector 130 is for accumulating the charged filaments discharged from the spinning unit 120, and may be configured to continuously move in a conveyor belt manner through a transfer means such as a roller 132, for example. The control unit 140 is for preventing a case in which the filament stream radiated from each of the spinning nozzles 122 rebounds from each other and spreads out from the path, and the control unit 140 includes at least a portion of the spinning nozzle pack 126. It is provided on both sides of the longitudinal direction. Induction unit 150 is applied with a voltage of the same polarity as the control unit 140. The induction unit 150 is installed around the elongated charged filament stream to guide the traveling direction of the stream. Induction unit 150 is provided in the form of a conductor plate or a conductor rod. The induction unit 150 is charged with the same polarity as the charged filament to induce the filament to be integrated in a limited area of the upper surface of the collector 130. The air conditioning unit 160 is to volatilize the solvent dissolved in the charged filament in the space between the spinning unit 120 and the collector 130 to exhaust it to the outside, for example, to absorb the solvent such as a suction fan and an exhaust fan. , Exhaust means and a plurality of air inlet slots 162. The positive voltage is excited by the output voltage of the high voltage unit 170. The high voltage unit 170 outputs a DC voltage in the range of 10 kV to 120 kV. When the raw material solution stored in the supply unit 110 is quantitatively supplied to the spinning unit 120 through the pump 114 and the distributor 116, the energization portion inside each spinning nozzle pack 126 of the spinning unit 120 is provided. The solution is charged. Subsequently, the charged solution is discharged toward the collector 130 in the form of fine filaments while passing through the capillary tube of the spinning nozzle 122. Here, the filaments are radiated while being stretched to a nanoscale diameter by a strong electric field formed between the collector 130 and the charged filaments. In this spinning process, due to the repulsive force between the filaments, the stream to be spread out of the traveling path to the outside is returned to the original position by the control unit 140 to maintain the correct traveling path. On the other hand, the induction unit 150 is installed above the collector 130 to surround the discharged stream, so that the stream which is about to go out of the path by the induction unit 150 is guided to the limited integration region on the collector 130. The filaments induced as described above are integrated on the collector belt 130 in the form of a conveyor belt or a rotating drum, or are integrated on the upper surface of the breathable support material 182 transported by the roller 180 to be made of nanofibers. It is made of a porous film on the web. An example of such an electrospinning apparatus is shown in US Patent No. 7,351,052.

The fibers or filaments constituting the integrated porous membrane on the web are preferably 0.05 to 10 탆 in diameter, and more preferably 0.05 to 5 탆. If the fiber diameter is too large, the specific surface area is reduced compared to the weight, and thus the internal loss characteristic of the speaker diaphragm is difficult to be maximized, and the specific gravity is too large to exhibit the light weight characteristics. The thickness of the porous membrane on the web is suitably between 5 and 300 μm, more preferably between 10 and 200 μm. The acoustic properties vary greatly depending on the polymer film characteristics, molding conditions, the degree of multilayering of the composite layer, and the shape of the speaker diaphragm. The thickness of the web is set in consideration of the total thickness of the composite speaker diaphragm to be finally manufactured. If the speaker diaphragm is too thick, the vibration efficiency decreases. If the speaker diaphragm is too thin, the strength of the speaker diaphragm is weakened, so that the wave diaphragm vibrates due to the parallax between the edge of the speaker diaphragm and the internal vibration without giving ripped or even vibration as a whole. The raw material of a fiber is not specifically limited. Any organic material, inorganic material or a mixture thereof can be used which can be formed into the fiber of the diameter. For example, polyacrylic resins such as poly methylmethacrylate (PMMA), polystyrene (PS), polyacrylic acid (PAA), and polyacrylonitrile (PAN), poly Polyvinyl resins such as polyvinyl chloride (PVC), polyvinyl alcohol (PVA), polyvinyl acetate (PVAc), polyethylene terephthalate (PET), polytrimethylene Polyester resin series such as terephthalate (Polytrimethylene Terephthalate (PTT)), polybutylene terephthalate (PBT), nylon (Nylon), polycarbonate, polyethylene oxide (PEO), polyurethane ( Polyurethane, PU), Polyvinylidene fluoride (PVdF), Polyvinylidene fluoride-hexafluoro propylene copolymer [poly (vinylidene fluoride) -co- (hexafluoropropylene), P (VDF-HFP)], polyvinylidene fluoride-chlorotrifluoroethylene copolymer [poly (vinylidene fluoride) -co- (chlorotrifluoroethylene), P (VDF- CTFE)], poly tetrafluoro ethylene-co-hexafluoro propyrene-co-vinylidene fluoride (THV), polyether ether ketone, polyphenylene Oxides (Poly phenylene oxide, PPO), poly phenylene sulfone (PPS), poly sulfone (PS), poly ethsulfone (PES), polyimide (PI), Substances such as polyimide (PEI), polyamide imide (PAI), polybenzimidazole (PBI), polybenzoxazole (PBO), poly aramid (Poly aramide) Suitable. It is also possible to produce a web obtained by mixing these materials and spinning them in a solution blended with two or more components, or a web obtained by spinning each component independently and simultaneously. When thermo-compression molding by mixing and spinning a binder material to increase the bonding force between the fiber strands inside the web to reinforce the strength of the web, the web is thermocompressed at high pressure and temperature, resulting in morphological deformation and generally increasing mechanical strength and specific gravity. Tends to. At this time, in order to maximize the strength of the fiber, at least one of the components of the web is made of a material having high mechanical strength, and at least one of the components is formed of a material that can maintain the adhesiveness and act as a binder, and then mix them in an appropriate ratio. After thermocompression, the physical properties can be maximized. The binder material is not particularly limited, but may be mechanically and thermally resistant to the working environment. The binder material may vary depending on the environment used, but acrylic resins, urethane resins, PVDF, and PVA are preferred. In the calendering process and the compression molding process, it should not be decomposed or altered to the environment where heat and pressure are applied.

4 is a view showing an example of a method for manufacturing a speaker diaphragm according to the present disclosure, by heat-pressing a web 30 made from electrospun fibers using a calender roll 50, When the web inner layer 31 maintains a fibrous shape, both outer surfaces thereof are thermally deformed to form a film or a web thermally deformable layer 32 close to the film. Through this, it is also possible to use itself as a speaker diaphragm, it is also possible to further polymerize the polymer film as needed to use as a speaker diaphragm. Calendaring can increase the mechanical strength of the web. In this process, it is necessary to maintain the fibrous living conditions in order to maintain high internal loss characteristics and light weight of the web. To do this, the surface of the web melts the fibrous phase with heat and pressure in calendering to form a film, and the inside of the web adjusts heat and pressure to form the fibrous alive. Nevertheless, the internal binder fiber phases melt to enclose the matrix fiber strands and change to be connected continuously, thereby greatly improving the overall mechanical properties. In order to control the change through the calendering work, it is preferable to form the material of the calender roll with a metal which is well heat-transferd and the surface fibers of the web are melted so that the film is formed smoothly. The final shape of the speaker diaphragm 13 is the final shape of the speaker diaphragm 13, and even in the molding process, heat and pressure are applied within a mold for a predetermined time, and a calendar effect is observed. There may be a problem of forming non-uniform properties even if film formation is formed as a whole or if some fibrous forms including the surface are alive. The pressurization and temperature conditions of the calender roll 50 depend on the type of raw materials used, but the linear pressure ranges from 1 to 200 Kgf / cm and the temperature from 30 to 200 ° C. Do. If the pressure and temperature are too low, the surface will not exhibit thermally deformed filming or will only be formed locally, which will be non-uniform and the rise in web strength will not be high. If the pressure and the temperature are too high, the heat deformation of the web proceeds not only to the surface but also to the inner fiber, resulting in film formation as the specific gravity is increased or the voids between the fibers disappear and the internal loss effect is weakened, and thus the advantages of the diaphragm disappear.

Web manufacturing

Example 1

15 g of polyimide was added to 85 g of dimethylacetamide to prepare a polymer spinning solution (12%). The prepared solution was made of fiber using an electrospinning apparatus. A 30 KV voltage was applied while feeding 6 ml solution per hour. The distance between the collector and the spinneret tip was 20 cm. The prepared web was press-molded using the temperature 70 degreeC and the pressure 60 kgf / cm calender roll.

[Example 2]

15 g of polyacrylonitrile was dissolved in 85 g of dimethylacetamide to prepare a polymer spinning solution (15%). The prepared solution was made of fiber using an electrospinning apparatus. A 30 KV voltage was applied while feeding 6 ml solution per hour. The distance between the collector and the spinneret tip was 20 cm. The prepared web was press-molded using the temperature 70 degreeC and the pressure 60 kgf / cm calender roll.

[Example 3]

A 15% acrylic solution was prepared by adding a mixed solvent of 42.5 g of ethyl acetate and 42.5 g of MEK (methyl ethyl ketone) to 15 g of acrylic resin. 15 g of polyimide was added to 85 g of dimethylacetamide to prepare a polymer spinning solution (12%). Fibers were prepared by electrospinning the prepared solutions using an electrospinning apparatus. A 30 KV voltage was applied while feeding 6 ml solution per hour. The distance between the collector and the spinneret tip was 20 cm. The prepared web was press-molded using the temperature 70 degreeC and the pressure 60 kgf / cm calender roll.

Example 4

A 15% acrylic solution was prepared by adding a mixed solvent of 42.5 g of ethyl acetate and 42.5 g of MEK (methyl ethyl ketone) to 15 g of acrylic resin. 15 g of polyacrylonitrile was dissolved in 85 g of dimethylacetamide to prepare a polymer spinning solution (15%). The prepared solution was made of fiber using an electrospinning apparatus. A 30 KV voltage was applied while feeding 6 ml solution per hour. The distance between the collector and the spinneret tip was 20 cm. The prepared web was press-molded using the temperature 70 degreeC and the pressure 60 kgf / cm calender roll.

FIG. 5 is a table showing physical properties before calendering in Examples 1 to 4, and FIG. 6 is a table showing physical properties after calendering in Examples 1 to 4, and the calendering is performed at a temperature of 70 ° C. and a pressure of 60 Kgf /. At cm. After calendering, it can be seen that both elastic modulus and tensile strength are improved. Long tensile strength. When using high sound pressure, the diaphragm is torn or does not give a uniform vibration as a whole, and the vibration of the diaphragm edge and the inside of the diaphragm is formed to generate wave waves, and the speaker diaphragm according to the present disclosure can solve such a problem. Able to know.

7 is a SEM photograph before thermocompression bonding of the fibrous web as in Example 1. FIG. It can be seen that a plurality of pores are formed.

FIG. 8 is an SEM photograph after thermocompression bonding of the fibrous web as in Example 1, and it can be confirmed that film formation is performed by thermal deformation of the fiber phase on the surface after thermocompression bonding.

9 is a SEM photograph after thermocompression bonding of the fibrous web as in Example 3, and it can be confirmed that the fibrous surface of the surface is thermally deformed after thermocompression and film formation has been progressed. This is because the melting point of the acrylic used together for many reasons is low, so that the heat deformation progresses and serves as a binder to fill the empty space of the surface.

Various embodiments of the present disclosure will be described below.

(1) The speaker diaphragm, wherein the web deformation layer is made of the same material as the web inner layer, and the pores are blocked and pressed by thermal deformation, so that the web deformation layer has fewer pores than the web inner layer. It can be seen that the film deforming layer is relative in relation to the web inner layer. However, the entire web should be thermally deformed to be usable in the speaker diaphragm, and as shown in FIG. 6, it is preferable to have elastic modulus of 10,000 kgf / cm ² or more and tensile strength of 100 kgf / cm ² or more.

(2) The speaker diaphragm, characterized in that the final thickness of the web is determined through a 10 to 90% thermal strain from a web having a thickness of 10 to 200 µm.

(3) The speaker diaphragm, wherein the web includes a binder for increasing the bonding force of the fibers and facilitating the formation of the web heat deformation layer.

According to one speaker diaphragm and a manufacturing method thereof according to the present disclosure, it is possible to satisfy a high elastic modulus and a high internal loss rate required for the speaker diaphragm.

According to another speaker diaphragm and a manufacturing method thereof according to the present disclosure, it is possible to satisfy the high elastic modulus and high internal loss rate required for the speaker diaphragm through a single material.

According to another speaker diaphragm and a method of manufacturing the same according to the present disclosure, it is possible to facilitate the overall tensile strength of the speaker diaphragm and film formation of the web heat deformation layer using the electrospun binder.

Web: 30 Web Inner Layer: 31 Web Heat Strain: 32

Claims (11)

In speaker diaphragm,
A portion of a web formed from electrospinning fibers, the web inner layer comprising a fibrous shape; And,
It is formed on at least one side of the web inner layer, and includes a heat-deformed web heat deformation layer,
The web inner layer has a higher internal loss rate than the web thermal layer, and the web thermal layer has a higher modulus of elasticity than the web inner layer. The method according to claim 1,
The web deformation layer is made of the same material as the web inner layer, and the pores are blocked and pressed by the thermal deformation, the speaker diaphragm, characterized in that it has fewer pores than the web inner layer. The method according to claim 1,
The final thickness of the web is a speaker diaphragm, characterized in that it is determined through a 10 to 90% thermal deformation from a web having a thickness of 10 ~ 200㎛. The method according to claim 2,
The web is a speaker diaphragm, characterized in that it comprises a binder to increase the bonding force of the fibers, and facilitate the formation of the web heat deformation layer. The method according to claim 1,
Speaker diaphragm, characterized in that the diameter of the fibers 0.05 ~ 10㎛. The method according to claim 1,
The web is a speaker diaphragm, characterized in that it comprises a binder to increase the bonding force of the fibers, and facilitate the formation of the web heat deformation layer. The method of claim 6,
And a web comprising a binder that is electrospun with the fibers. The method according to claim 1,
A fiber made of at least one of polyacrylic resin, polyvinyl resin and polyester resin. The method according to claim 1,
Fibers are made of polymethylmethacrylate (PMMA), polystyrene (PS), polyacrylic acid (PAA), polyacrylonitrile (PAN), polyvinyl chloride (PVC) ), Polyvinyl alcohol (PVA), polyvinyl acetate (PVAc), polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polybutylene terephthalate Polybutylne terephthalate (PBT), nylon, polycarbonate, polyethylene oxide (PEO), polyurethane (PU), polyvinylidene fluoride (PVdF), polyvinylidene Fluoride-hexafluoropropylene copolymers [poly (vinylidene fluoride) -co- (hexafluoropropylene), P (VDF-HFP)], polyvinylidene fluoride-chloro Trifluoroethylene copolymer [poly (vinylidene fluoride) -co- (chlorotrifluoroethylene), P (VDF-CTFE)], polytetrafluoroethylenehexafluoropropylenevinylidene fluoride copolymer (poly tetrafluoro ethylene-co-hexafluoro propyrene- co-vinylidene fluoride (THV), polyether ether ketone, poly phenylene oxide (PPO), poly phenylene sulfone (PPS), poly sulfone (Poly sulfone, PS ), Poly ehter sulfone (PES), Polyimide (PI), Polyimide (PEI), Polyamide imide (PAI), Polybenzimidazole, PBI ), Polybenzoxazole (Polybenzoxazole, PBO), a speaker diaphragm, characterized in that at least one selected from the group consisting of poly aramide (Poly aramide). The method of claim 7,
The binder is a diaphragm of at least one of an acrylic resin, urethane resin, polyvinylidene fluoride (Polyvinylidene fluoride, PVdF), and polyvinyl alcohol (Polyvinyl alcohol, PVA). The method according to claim 1,
The web deformation layer is made of the same material as the web inner layer, and the pores are blocked and pressed by thermal deformation, and thus have less pores than the web inner layer.
The final thickness of the web is determined through a 10 to 90% thermal strain from a web having a thickness of 10 to 200 μm,
And the web includes an electrospun binder that enhances the bond strength of the fibers and facilitates the formation of a web heat deflection layer.

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